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2016年
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第 1 条,共 261 条
标题: Simulation of the effects of coated material SEY property on output electron energy distribution and gain of microchannel plates
作者: Chen, L (Chen, Lin); Wang, XC (Wang, Xingchao); Tian, JS (Tian, Jinshou); Liu, CL (Liu, Chunliang); Liu, HL (Liu, Hulin); Chen, P (Chen, Ping); Wei, YL (Wei, Yonglin); Sai, XF (Sai, Xiaofeng); Sun, JN (Sun, Jianning); Si, SG (Si, Shuguang); Wang, X (Wang, Xing); Lu, Y (Lu, Yu); Tian, LP (Tian, Liping); Hui, DD (Hui, Dandan); Guo, LH (Guo, Lehui)
来源出版物: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 卷: 840 页: 133-138 DOI: 10.1016/j.nima.2016.10.014 出版年: DEC 21 2016
摘要: To obtain a high spatial resolution of a image intensifier based on microchannel plate (MCP), the long tail in the exit energy distribution of the output electrons (EDOE) is undesirable. The existing solution is increasing the penetration depth of the MCP output electrode, which will result in a serious gain reduction. Coating the MCP output electrode with efficient secondary electron yield (SEX) materials is supposed to be an effective approach to suppress the unfavorable tail component in the EDOE without negative effects on the gain. In our work, a three-dimensional MCP single channel model is developed in CST STUDIO SLTITE to systematically investigate the dependences of the EDOE and the gain on the SEY property of the coated material, bawd on the Finite Integral Technique and Monte Carlo method. The results show that besides the high SEY of the coated material, the low incident energy corresponding to the peak SEY is another essential element affecting the electron yield in the final stage of multiplication and suppressing the output energy spread.
入藏号: WOS:000390825800018
ISSN: 0168-9002
eISSN: 1872-9576
第 2 条,共 261 条
标题: Two-Photon Laser Scanning Stereomicroscopy for Fast Volumetric Imaging
作者: Yang, YL (Yang, Yanlong); Yao, BL (Yao, Baoli); Lei, M (Lei, Ming); Dan, D (Dan, Dan); Li, RZ (Li, Runze); Van Horn, M (Van Horn, Mark); Chen, X (Chen, Xun); Li, Y (Li, Yang); Ye, T (Ye, Tong)
来源出版物: PLOS ONE 卷: 11 期: 12 文献号: e0168885 DOI: 10.1371/journal.pone.0168885 出版年: DEC 20 2016
摘要: Bessel beams have been successfully used in two-photon laser scanning fluorescence microscopy to extend the depth of field (EDF), which makes it possible to observe fast events volumetrically. However, the depth information is lost due to integration of fluorescence signals along the propagation direction. We describe the design and implementation of two-photon lasers scanning stereomicroscopy, which allows viewing dynamic processes in three-dimensional (3D) space stereoscopically in real-time with shutter glasses at the speed of 1.4 volumes per second. The depth information can be appreciated by human visual system or be recovered with correspondence algorithms for some cases.
入藏号: WOS:000392842900083
PubMed ID: 27997624
ISSN: 1932-6203
第 3 条,共 261 条
标题: Toward solving the Steiner travelling salesman problem on urban road maps using the branch decomposition of graphs
作者: Xia, YJ (Xia, Yingjie); Zhu, MZ (Zhu, Mingzhe); Gu, QP (Gu, Qianping); Zhang, LM (Zhang, Luming); Li, XL (Li, Xuelong)
来源出版物: INFORMATION SCIENCES 卷: 374 页: 164-178 DOI: 10.1016/j.ins.2016.09.043 出版年: DEC 20 2016
摘要: The Steiner travelling salesman problem (STSP) is an important issue in intelligent transportation systems and has various practical applications, such as travelling and parcel delivery. In this study, we consider the STSP in real-world road maps, i.e., given a road map with a set of service points or intersections, selection of the representative vertices of a graph G to determine a closed route so a vehicle can visit each service point at least once with the minimum cost. It has been theoretically proved that the STSP and its ancestor, travelling salesman problem, are NP-hard. However, it has been empirically demonstrated that they can be solved efficiently on planar graphs with small branchwidths. Therefore, we propose a branch decomposition-based extraction algorithm for the STSP in planar graphs. Our algorithm can solve the STSP in a planar graph G with a time complexity of 2(O(bw(G))) n(O(1)), where bw(G) is the branchwidth of G. In the case of planar graphs with a small branchwidth, our algorithm performs efficiently. We evaluated our algorithm by applying it to real-world urban road maps, which demonstrated the suitability of our method for real-world applications. (C) 2016 Elsevier Inc. All rights reserved.
入藏号: WOS:000386645800011
ISSN: 0020-0255
eISSN: 1872-6291
第 4 条,共 261 条
标题: Ultrafast destructuring of laser-irradiated tungsten: Thermal or nonthermal process
作者: Zhang, H (Zhang, H.); Li, C (Li, C.); Bevillon, E (Bevillon, E.); Cheng, G (Cheng, G.); Colombier, JP (Colombier, J. P.); Stoian, R (Stoian, R.)
来源出版物: PHYSICAL REVIEW B 卷: 94 期: 22 文献号: 224103 DOI: 10.1103/PhysRevB.94.224103 出版年: DEC 16 2016
摘要: The time needed for metals to respond structurally to electronic excitation is usually considered to be set by picosecond-long electron-phonon coupling, hence limiting the rapid achievement of structural phase changes. Via time-resolved ellipsometry, we show that fs laser excitation of tungsten determines unexpectedly fast optical and structural transformations, almost on the time scale of the laser pulse, with sub-ps destructuring of matter. If at low energies, below the damage threshold, Fermi redistribution within the d-band pseudogap populates localized states that screen ions, in ablative ranges, at electronic energies above 4 eV, a charge deficit appears on bonding orbitals generating bond-softening and ionic repulsion in spite of the metallic environment. Along pressure gradients, this rapidly destabilizes the structure. Sub-ps ablation occurs, challenging thermally driven scenarios of phonon activation. First-principles and hydrodynamic models show that ablation interrelates nonclassical charge distortions, electronic stress, and classical electron-phonon dynamics, with the coexistence of thermal and nonthermal effects on scales believed to be prohibitive for the former.
入藏号: WOS:000390251300002
作者识别号:
作者        ResearcherID 号        ORCID 号
Colombier, Jean-Philippe         B-8884-2012         0000-0001-8462-7019
ISSN: 2469-9950
eISSN: 2469-9969
第 5 条,共 261 条
标题: Modeling the encoding structure and spatial resolution of photon counting imagers with Vernier anode readout
作者: Yang, H (Yang, Hao); Zhao, BS (Zhao, Baosheng); Yan, QR (Yan, Qiurong); Liu, YA (Liu, Yong'an)
来源出版物: CHINESE OPTICS LETTERS 卷: 14 期: 12 文献号: 121102 DOI: 10.3788/COL201614.121102 出版年: DEC 10 2016
摘要: We present the spatial resolution estimation methods for a photon counting system with a Vernier anode. A limiting resolution model is provided according to discussions of surface encoding structure and quantized noise. The limiting resolution of a Vernier anode is revealed to be significantly higher than that of a microchannel plate. The relationship between the actual spatial resolution and equivalent noise charge of a detector is established by noise analysis and photon position reconstruction. The theoretical results are demonstrated to be in good agreement with the experimental results for a 1.2 mm pitch Vernier anode.
入藏号: WOS:000391128900015
ISSN: 1671-7694
第 6 条,共 261 条
标题: A target detection method for hyperspectral image based on mixture noise model
作者: Zheng, XT (Zheng, Xiangtao); Yuan, Y (Yuan, Yuan); Lu, XQ (Lu, Xiaoqiang)
来源出版物: NEUROCOMPUTING 卷: 216 页: 331-341 DOI: 10.1016/j.neucom.2016.08.015 出版年: DEC 5 2016
摘要: Subpixel hyperspectral detection is a kind of method which tries to locate targets in a hyperspectral image when the spectrum of the targets is given. Due to its subpixel nature, targets are often smaller than one pixel, which increases the difficulty of detection. Many algorithms have been proposed to tackle this problem, most of which model the noise in all spatial points of hyperspectral image by multivariate normal distribution. However, this model alone may not be an appropriate description of the noise distribution in hyperspectral image. After carefully studying the distribution of hyperspectral image, it is concluded that the gradient of noise also obeys normal distribution. In this paper two detectors are proposed: mixture gradient structured detector (MGSD) and mixture gradient unstructured detector (MGUD). These detectors are based on a new model which takes advantage of the distribution of the gradient of the noise. This makes the detectors more accordant with the practical situation. To evaluate the performance of the proposed detectors, three different data sets, including one synthesized data set and two real-world data sets, are used in the experiments. Results show that the proposed detectors have better performance than current subpixel detectors. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000388777400031
ISSN: 0925-2312
eISSN: 1872-8286
第 7 条,共 261 条
标题: Demonstration of a stable and uniform single-wavelength erbium-doped fiber laser based on microfiber knot resonator
作者: Xu, YP (Xu, Yiping); Ren, LY (Ren, Liyong); Ma, CJ (Ma, Chengju); Kong, XD (Kong, Xudong); Ren, KL (Ren, Kaili)
来源出版物: OPTICAL ENGINEERING 卷: 55 期: 12 文献号: 126111 DOI: 10.1117/1.OE.55.12.126111 出版年: DEC 2016
摘要: We propose and demonstrate an application of microfiber knot resonator (MKR) in the generation of a stable and uniform single-wavelength erbium-doped fiber laser (EDFL). An MKR was fabricated using a microfiber a few micrometers in diameter. By embedding the MKR to the ring cavity of the EDFL, a laser with a wavelength of 1558.818 nm and a 3-dB linewidth of 0.0149 nm is demonstrated. The side mode suppression ratio of the laser is about 30 dB, and the maximum power fluctuation is about 0.85 dB. The results demonstrate that the MKR can be employed as a high-performance comb filter to realize a stable and uniform fiber laser. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000396372900073
作者识别号:
作者        ResearcherID 号        ORCID 号
Ren, Liyong         F-5518-2014         0000-0002-7547-7511
ISSN: 0091-3286
eISSN: 1560-2303
第 8 条,共 261 条
标题: Graphene-induced unique polarization tuning properties of excessively tilted fiber grating
作者: Jiang, BQ (Jiang, Biqiang); Yin, GL (Yin, Guolu); Zhou, KM (Zhou, Kaiming); Wang, CL (Wang, Changle); Gan, XT (Gan, Xuetao); Zhao, JL (Zhao, Jianlin); Zhang, L (Zhang, Lin)
来源出版物: OPTICS LETTERS 卷: 41 期: 23 页: 5450-5453 DOI: 10.1364/OL.41.005450 出版年: DEC 1 2016
摘要: By exploiting the polarization-sensitive coupling effect of graphene with the optical mode, we investigate the polarization modulation properties of a hybrid waveguide of graphene-integrated excessively tilted fiber grating (Ex-TFG). The theoretical analysis and experimental results demonstrate that the real and imaginary parts of complex refractive index of few-layer graphene exhibit different effects on transverse electric (TE) and transverse magnetic (TM) claddingmodes of the Ex-TFG, enabling stronger absorption in the TE mode and more wavelength shift in the TM mode. Furthermore, the surrounding refractive index can modulate the complex optical constant of graphene and then the polarization properties of the hybrid waveguide, such as resonant wavelength and peak intensity. Therefore, the unique polarization tuning property induced by the integration of the graphene layer with Ex-TFG may endow potential applications in all-in-one fiber modulators, fiber lasers, and biochemical sensors. (C) 2016 Optical Society of America
入藏号: WOS:000389654000009
PubMed ID: 27906210
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhou, Kaiming         E-5903-2011         0000-0002-6011-1912
Yin, Guolu         D-3664-2014         0000-0002-8004-4198
ISSN: 0146-9592
eISSN: 1539-4794
第 9 条,共 261 条
标题: Hyperspectral Image Classification via Multitask Joint Sparse Representation and Stepwise MRF Optimization
作者: Yuan, Y (Yuan, Yuan); Lin, JZ (Lin, Jianzhe); Wang, Q (Wang, Qi)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 12 页: 2966-2977 DOI: 10.1109/TCYB.2015.2484324 出版年: DEC 2016
摘要: Hyperspectral image (HSI) classification is a crucial issue in remote sensing. Accurate classification benefits a large number of applications such as land use analysis and marine resource utilization. But high data correlation brings difficulty to reliable classification, especially for HSI with abundant spectral information. Furthermore, the traditional methods often fail to well consider the spatial coherency of HSI that also limits the classification performance. To address these inherent obstacles, a novel spectral-spatial classification scheme is proposed in this paper. The proposed method mainly focuses on multitask joint sparse representation (MJSR) and a stepwise Markov random filed framework, which are claimed to be two main contributions in this procedure. First, the MJSR not only reduces the spectral redundancy, but also retains necessary correlation in spectral field during classification. Second, the stepwise optimization further explores the spatial correlation that significantly enhances the classification accuracy and robustness. As far as several universal quality evaluation indexes are concerned, the experimental results on Indian Pines and Pavia University demonstrate the superiority of our method compared with the state-of-the-art competitors.
入藏号: WOS:000388923100023
PubMed ID: 26485729
ISSN: 2168-2267
eISSN: 2168-2275
第 10 条,共 261 条
标题: Hyperspectral Anomaly Detection by Graph Pixel Selection
作者: Yuan, Y (Yuan, Yuan); Ma, DD (Ma, Dandan); Wang, Q (Wang, Qi)
来源出版物: IEEE Transactions on Cybernetics 卷: 46 期: 12 页: 3123-3134 DOI: 10.1109/TCYB.2015.2497711 出版年: DEC 2016
摘要: Hyperspectral anomaly detection (AD) is an important problem in remote sensing field. It can make full use of the spectral differences to discover certain potential interesting regions without any target priors. Traditional Mahalanobis-distance-based anomaly detectors assume the background spectrum distribution conforms to a Gaussian distribution. However, this and other similar distributions may not be satisfied for the real hyperspectral images. Moreover, the background statistics are susceptible to contamination of anomaly targets which will lead to a high false-positive rate. To address these intrinsic problems, this paper proposes a novel AD method based on the graph theory. We first construct a vertex- and edge-weighted graph and then utilize a pixel selection process to locate the anomaly targets. Two contributions are claimed in this paper: 1) no background distributions are required which makes the method more adaptive and 2) both the vertex and edge weights are considered which enables a more accurate detection performance and better robustness to noise. Intensive experiments on the simulated and real hyperspectral images demonstrate that the proposed method outperforms other benchmark competitors. In addition, the robustness of the proposed method has been validated by using various window sizes. This experimental result also demonstrates the valuable characteristic of less computational complexity and less parameter tuning for real applications.
入藏号: WOS:000388923100035
PubMed ID: 26600560
作者识别号:
作者        ResearcherID 号        ORCID 号
Wang, Qi                  0000-0002-7028-4956
ISSN: 2168-2267
eISSN: 2168-2275
第 11 条,共 261 条
标题: Weakly Supervised Multilabel Clustering and its Applications in Computer Vision
作者: Xia, YJ (Xia, Yingjie); Nie, LQ (Nie, Liqiang); Zhang, LM (Zhang, Luming); Yang, Y (Yang, Yi); Hong, RC (Hong, Richang); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 12 页: 3220-3232 DOI: 10.1109/TCYB.2015.2501385 出版年: DEC 2016
摘要: Clustering is a useful statistical tool in computer vision and machine learning. It is generally accepted that introducing supervised information brings remarkable performance improvement to clustering. However, assigning accurate labels is expensive when the amount of training data is huge. Existing supervised clustering methods handle this problem by transferring the bag-level labels into the instance-level descriptors. However, the assumption that each bag has a single label limits the application scope seriously. In this paper, we propose weakly supervised multilabel clustering, which allows assigning multiple labels to a bag. Based on this, the instance-level descriptors can be clustered with the guidance of bag-level labels. The key technique is a weakly supervised random forest that infers the model parameters. Thereby, a deterministic annealing strategy is developed to optimize the nonconvex objective function. The proposed algorithm is efficient in both the training and the testing stages. We apply it to three popular computer vision tasks: 1) image clustering; 2) semantic image segmentation; and 3) multiple objects localization. Impressive performance on the state-of-the-art image data sets is achieved in our experiments.
入藏号: WOS:000388923100043
作者识别号:
作者        ResearcherID 号        ORCID 号
Yang, Yi         B-9273-2017         0000-0001-5528-0546
ISSN: 2168-2267
eISSN: 2168-2275
第 12 条,共 261 条
标题: Similarity Constraints-Based Structured Output Regression Machine: An Approach to Image Super-Resolution
作者: Deng, C (Deng, Cheng); Xu, J (Xu, Jie); Zhang, KB (Zhang, Kaibing); Tao, DC (Tao, Dacheng); Gao, XB (Gao, Xinbo); Li, XL (Li, Xuelong)
来源出版物: IEEE Transactions on Neural Networks and Learning Systems 卷: 27 期: 12 页: 2472-2485 DOI: 10.1109/TNNLS.2015.2468069 出版年: DEC 2016
摘要: For regression-based single-image super-resolution (SR) problem, the key is to establish a mapping relation between high-resolution (HR) and low-resolution (LR) image patches for obtaining a visually pleasing quality image. Most existing approaches typically solve it by dividing the model into several single-output regression problems, which obviously ignores the circumstance that a pixel within an HR patch affects other spatially adjacent pixels during the training process, and thus tends to generate serious ringing artifacts in resultant HR image as well as increase computational burden. To alleviate these problems, we propose to use structured output regression machine (SORM) to simultaneously model the inherent spatial relations between the HR and LR patches, which is propitious to preserve sharp edges. In addition, to further improve the quality of reconstructed HR images, a nonlocal (NL) self-similarity prior in natural images is introduced to formulate as a regularization term to further enhance the SORM-based SR results. To offer a computation-effective SORM method, we use a relative small nonsupport vector samples to establish the accurate regression model and an accelerating algorithm for NL self-similarity calculation. Extensive SR experiments on various images indicate that the proposed method can achieve more promising performance than the other state-of-the-art SR methods in terms of both visual quality and computational cost.
入藏号: WOS:000388919600002
PubMed ID: 26357410
ISSN: 2162-237X
eISSN: 2162-2388
第 13 条,共 261 条
标题: Scalable Linear Visual Feature Learning via Online Parallel Nonnegative Matrix Factorization
作者: Zhao, XY (Zhao, Xueyi); Li, X (Li, Xi); Zhang, ZF (Zhang, Zhongfei); Shen, CH (Shen, Chunhua); Zhuang, YT (Zhuang, Yueting); Gao, LX (Gao, Lixin); Li, XL (Li, Xuelong)
来源出版物: IEEE Transactions on Neural Networks and Learning Systems 卷: 27 期: 12 页: 2628-2642 DOI: 10.1109/TNNLS.2015.2499273 出版年: DEC 2016
摘要: Visual feature learning, which aims to construct an effective feature representation for visual data, has a wide range of applications in computer vision. It is often posed as a problem of nonnegative matrix factorization (NMF), which constructs a linear representation for the data. Although NMF is typically parallelized for efficiency, traditional parallelization methods suffer from either an expensive computation or a high runtime memory usage. To alleviate this problem, we propose a parallel NMF method called alternating least square block decomposition (ALSD), which efficiently solves a set of conditionally independent optimization subproblems based on a highly parallelized fine-grained grid-based blockwise matrix decomposition. By assigning each block optimization subproblem to an individual computing node, ALSD can be effectively implemented in a MapReduce-based Hadoop framework. In order to cope with dynamically varying visual data, we further present an incremental version of ALSD, which is able to incrementally update the NMF solution with a low computational cost. Experimental results demonstrate the efficiency and scalability of the proposed methods as well as their applications to image clustering and image retrieval.
入藏号: WOS:000388919600014
PubMed ID: 26625429
作者识别号:
作者        ResearcherID 号        ORCID 号
Li, Xi         L-1234-2013         
ISSN: 2162-237X
eISSN: 2162-2388
第 14 条,共 261 条
标题: 126W fiber laser at 1018nm and its application in tandem pumped fiber amplifier
作者: Yang, HN (Yang, Hening); Zhao, W (Zhao, Wei); Si, JH (Si, Jinhai); Zhao, BY (Zhao, Baoyin); Zhu, YG (Zhu, Yonggang)
来源出版物: JOURNAL OF OPTICS 卷: 18 期: 12 文献号: 125801 DOI: 10.1088/2040-8978/18/12/125801 出版年: DEC 2016
摘要: We report on a 126W fiber laser operating at 1018 nm with an optical efficiency of 75%. The optimal length for such a fiber laser is theoretically analyzed using steady-state rate equations including amplified spontaneous emission. Excellent agreement on the maximum output power is achieved between the numerical result and the experimental counterpart. Furthermore, a monolithic tandem pumped fiber amplifier is established by using conventional 30/250 mu m double clad ytterbium-doped fiber, and 185W output power with 85% optical efficiency is realized.
入藏号: WOS:000388839000001
ISSN: 2040-8978
eISSN: 2040-8986
第 15 条,共 261 条
标题: Online fabrication scheme of helical long-period fiber grating for liquid-level sensing
作者: Ren, KL (Ren, Kaili); Ren, LY (Ren, Liyong); Liang, J (Liang, Jian); Kong, XD (Kong, Xudong); Ju, HJ (Ju, Haijuan); Xu, YP (Xu, Yiping); Wu, ZX (Wu, Zhaoxin)
来源出版物: APPLIED OPTICS 卷: 55 期: 34 页: 9675-9679 DOI: 10.1364/AO.55.009675 出版年: DEC 1 2016
摘要: We present a novel online fabrication scheme of helical long-period fiber gratings (H-LPFGs) by directly twisting a standard single-mode fiber (SMF) in a microheater. This is done by taking advantage of the inherent core-cladding eccentricity in SMF. We adopt a fiber optic rotary joint to eliminate the accompanying twisting spiral for real-time spectral monitoring and a stepping mechanical system to accurately control the twisting length in fabrication. As a consequence, low-cost and high-quality H-LPFGs can be readily fabricated. Meanwhile, by using this kind of H-LPFG, we design a simple and low-cost wavelength-interrogated liquid-level sensor with a high sensitivity of 0.1 nm/mm. (C) 2016 Optical Society of America
入藏号: WOS:000388938200031
PubMed ID: 27958456
会议名称: Biennial Conference on Applied Optics on Advanced Infrared Technology and Applications (AITA)
会议日期: SEP 29-OCT 02, 2015
会议地点: Pisa, ITALY
作者识别号:
作者        ResearcherID 号        ORCID 号
Ren, Liyong         F-5518-2014         0000-0002-7547-7511
ISSN: 1559-128X
eISSN: 2155-3165
第 16 条,共 261 条
标题: Pedestrian Detection Inspired by Appearance Constancy and Shape Symmetry
作者: Cao, JL (Cao, Jiale); Pang, YW (Pang, Yanwei); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 12 页: 5538-5551 DOI: 10.1109/TIP.2016.2609807 出版年: DEC 2016
摘要: Most state-of-the-art methods in pedestrian detection are unable to achieve a good trade-off between accuracy and efficiency. For example, ACF has a fast speed but a relatively low detection rate, while checkerboards have a high detection rate but a slow speed. Inspired by some simple inherent attributes of pedestrians (i.e., appearance constancy and shape symmetry), we propose two new types of non-neighboring features: side-inner difference features (SIDF) and symmetrical similarity features (SSFs). SIDF can characterize the difference between the background and pedestrian and the difference between the pedestrian contour and its inner part. SSF can capture the symmetrical similarity of pedestrian shape. However, it is difficult for neighboring features to have such above characterization abilities. Finally, we propose to combine both non-neighboring features and neighboring features for pedestrian detection. It is found that non-neighboring features can further decrease the log-average miss rate by 4.44%. The relationship between our proposed method and some state-of-the-art methods is also given. Experimental results on INRIA, Caltech, and KITTI data sets demonstrate the effectiveness and efficiency of the proposed method. Compared with the state-of-the-art methods without using CNN, our method achieves the best detection performance on Caltech, outperforming the second best method (i.e., checkerboards) by 2.27%. Using the new annotations of Caltech, it can achieve 11.87% miss rate, which outperforms other methods.
入藏号: WOS:000388205100003
PubMed ID: 27654480
ISSN: 1057-7149
eISSN: 1941-0042
第 17 条,共 261 条
标题: Wavelength tunable CW red laser generated based on an intracavity-SFG composite cavity
作者: Zhang, ZN (Zhang, Z. N.); Bai, Y (Bai, Y.); Lei, GZ (Lei, G. Z.); Bai, B (Bai, B.); Sun, YX (Sun, Y. X.); Hu, MX (Hu, M. X.); Wang, C (Wang, C.); Bai, JT (Bai, J. T.)
来源出版物: LASER PHYSICS LETTERS 卷: 13 期: 12 文献号: 125402 DOI: 10.1088/1612-2011/13/12/125402 出版年: DEC 2016
摘要: We report a wavelength-tunable watt-level continuous wave (CW) red laser that uses a composite cavity based on an intracavity sum-frequency generation (SFG). The composite cavity is composed of a LD side-pumped Nd: GdVO4 p-polarized 1062.9 nm resonant cavity and a resonant optical parametric oscillator (SRO) of s-polarized signal light using a periodically poled crystal MgO:PPLN. Based on the temperature tuning from 30 degrees C to 200 degrees C, the CW red laser beams are obtained in a tunable waveband from 634.4 nm to 649.1 nm, corresponding to a tunable output waveband from 3278.0 nm to 2940.2 nm of the mid-infrared idler lights. The maximum CW output power of the red laser at 634.4 nm and the idler light at 3278.0 nm reach 3.03 W and 4.13 W under 30 degrees C, respectively.
入藏号: WOS:000387909000001
ISSN: 1612-2011
eISSN: 1612-202X
第 18 条,共 261 条
标题: A robust haze-removal scheme in polarimetric dehazing imaging based on automatic identification of sky region
作者: Zhang, WF (Zhang, Wenfei); Liang, J (Liang, Jian); Ju, HJ (Ju, Haijuan); Ren, LY (Ren, Liyong); Qu, ES (Qu, Enshi); Wu, ZX (Wu, Zhaoxin)
来源出版物: OPTICS AND LASER TECHNOLOGY 卷: 86 页: 145-151 DOI: 10.1016/j.optlastec.2016.07.015 出版年: DEC 2016
摘要: Quality enhancement of images acquired in hazy conditions is a significant research area in civil and military applications. The polarimetric dehazing methods have been exploited to dehaze hazy images and have proven to be effective in enhancing their quality. In this paper, by combining the polarimetric imaging technique and the dark channel prior technique, a robust haze-removal scheme is presented for the first time. On the one hand, the polarimetric imaging technique has advantages in recovering detailed information well, especially in dense hazy conditions; on the other hand, the dark channel prior technique provides a much more precise and convenient way to estimate the airlight radiance through extracting the sky region automatically. The experiments verify the practicability and effectiveness of the proposed dehazing scheme in quality enhancement of hazy images. Furthermore, comparison study demonstrates that the proposed scheme is superior to some sophisticated methods in terms of the visibility and contrast. We believe this scheme is beneficial in the image dehazing applications, especially for real-time applications. (C) 2016 Elsevier Ltd. All rights reserved.
入藏号: WOS:000382340900019
作者识别号:
作者        ResearcherID 号        ORCID 号
Ren, Liyong         F-5518-2014         0000-0002-7547-7511
ISSN: 0030-3992
eISSN: 1879-2545
第 19 条,共 261 条
标题: Super-Resolution Imaging at Mid-Infrared Waveband in Graphene-nanocavity formed on meta-surface
作者: Yang, JZ (Yang, Jingzhong); Wang, TS (Wang, Taisheng); Chen, ZL (Chen, Zuolong); Hu, BL (Hu, Bingliang); Yu, WX (Yu, Weixing)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 37898 DOI: 10.1038/srep37898 出版年: NOV 29 2016
摘要: Plasmonic structured illumination microscopy (PSIM) is one of the promising wide filed optical imaging methods, which takes advantage of the surface plasmons to break the optical diffraction limit and thus to achieve a super-resolution optical image. To further improve the imaging resolution of PSIM, we propose in this work a so called graphene nanocavity on meta-surface structure (GNMS) to excite graphene surface plasmons with a deep sub-wavelength at mid-infrared waveband. It is found that surface plasmonic interference pattern with a period of around 52 nm can be achieved in graphene nanocavity formed on structured meta-surface for a 7 mu m wavelength incident light. Moreover, the periodic plasmonic interference pattern can be tuned by simply changing the nanostructures fabricated on meta-surface for different application purposes. At last, the proposed GNMS structure is applied for super-resolution imaging in PSIM and it is found that an imaging resolution of 26 nm can be achieved, which is nearly 100 folds higher than that can be achieved by conventional epi-fluorescence microscopy. In comparison with visible waveband, mid-infrared is more gently and safe to biological cells and thus this work opens the new possibility for optical super-resolution imaging at mid-infrared waveband for biological research field.
入藏号: WOS:000389001900001
PubMed ID: 27897207
作者识别号:
作者        ResearcherID 号        ORCID 号
Yu, Weixing         G-3658-2012         0000-0002-3216-526X
ISSN: 2045-2322
第 20 条,共 261 条
标题: Accelerating incoherent hollow beams beyond the paraxial regime
作者: Yang, YL (Yang, Yanlong); Yan, SH (Yan, Shaohui); Yu, XH (Yu, Xianghua); Li, MM (Li, Manman); Yao, BL (Yao, Baoli)
来源出版物: OPTICS EXPRESS 卷: 24 期: 24 页: 27683-27690 DOI: 10.1364/OE.24.027683 出版年: NOV 28 2016
摘要: We propose a non-paraxial hollow accelerating beam, which is formed by incoherently superposing two well-designed coherent accelerating beams. Very interestingly, this incoherent superposition does not hamper the acceleration dynamics pertaining to the coherent ones, but results in a hollow intensity pattern in the cross section transverse to the circular accelerating trajectory. By a simple optimization, this hollow cross section pattern can be effectively extended to an angle close to 90 degrees. The magnitude and the phase of the angular spectrum of the beam are given followed by a suggested scheme to generate the beam in practice. Such highly self-bending hollow beams may find applications in some fields such as optical manipulation. (C) 2016 Optical Society of America
入藏号: WOS:000389468200058
PubMed ID: 27906337
ISSN: 1094-4087
第 21 条,共 261 条
标题: Optimization of the 3-inch photomultiplier tube for the neutrino detection
作者: Guo, LH (Guo Le-Hui); Tian, JS (Tian Jin-Shou); Lu, Y (Lu Yu); Li, HW (Li Hong-Wei)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 22 文献号: 228501 DOI: 10.7498/aps.65.228501 出版年: NOV 20 2016
摘要: Photomultiplier tubes (PMTs) widely used in neutrino detectors are critical to reconstructing the direction of the neutrino accurately. Large photocathode coverage, compact design and good time properties for single-photoelectron light are essential performances to meet the requirements for the next generation detectors. Therefore, a novel digital optical module housing 31 3-inch. diameter PMTs is developed. In order to maximize the effective photocathode area and improve the time performance, a modified PMT with a larger photocathode area and 10 dynodes is optimized with the aid of the CST Particle Studio in this paper. Based on the Monte Carlo method and finite integration theory, the main characteristics of the modified PMT, such as uniformity, collection efficiency, gain and transit-time spread, are investigated. As the earlier stages of the PMT contribute the greatest weight to the total transit time spread, the transit time spread of single-photoelectron from photocathode to the first dynode (TTSCD1) is discussed mainly in this paper. The influences of the dynodes position on collection efficiency and TTSCD1 are analyzed. The voltage ratio scheme is also optimized slightly to obtain better collection efficiency and minimum TTSCD1. By tracing the trajectories of secondary electrons from the first to the second dynode stage, dynodes are optimized for improving timing performance and secondary electrons collection efficiency. Direct collection efficiency of secondary electrons from the first dynode to the second is improved from 56.38% to 61.01%. The effective photocathode diameter of the modified PMT is increased from traditional 72 mm to 77.5 mm and the effective area of photocathode is increased by 30.87% compared with the traditional one. What is more, the length of the new PMT is reduced to 103 mm so that the available space of the multi-PMT digital optical module is increased by 63.09% compared with the traditional one containing the high-voltage power supplies, front-end and readout electronics, refrigerating equipment, etc. The simulation results show that the mean collection efficiency of the modified PMT is similar to 96.40% with the supply voltage of 1000 V and it changes little by changing the supply voltage from 900 V to 1300 V. The mean transit time spread from photocathode to the first dynode is similar to 1 ns which is better than the transit time spread of the traditional model. And the gain can reach above 10 6 with a supply voltage of above 1100 V.
入藏号: WOS:000389598500031
ISSN: 1000-3290
第 22 条,共 261 条
标题: Mode Splitter Without Changing the Mode Order in SOI Waveguide
作者: Liao, JW (Liao, Jianwen); Zhang, LX (Zhang, Lingxuan); Liu, ML (Liu, Mulong); Wang, LR (Wang, Leiran); Wang, WQ (Wang, Weiqiang); Wang, GX (Wang, Guoxi); Ruan, C (Ruan, Chi); Zhao, W (Zhao, Wei); Zhang, WF (Zhang, Wenfu)
来源出版物: IEEE PHOTONICS TECHNOLOGY LETTERS 卷: 28 期: 22 页: 2597-2600 DOI: 10.1109/LPT.2016.2606496 出版年: NOV 15 2016
摘要: We proposed a mode splitter based on directional coupler (DC), which is capable of splitting the TE0 and TE1 modes without changing the mode order. It is found that high coupling efficiency (higher than -1 dB), low mode crosstalk (less than -16 dB), wide bandwidth (similar to 100 nm), and large fabrication tolerance (+/- 10 nm) can be obtained by a 24.4 mu m coupling length DC structure, which is composed of a strip and a slot silicon waveguide. This design represents a first step toward mode splitter without changing the mode order, which can find important potential applications, such as optical isolation and mode division multiplexing (MDM), in large-scale photonic integrated circuits (PICs).
入藏号: WOS:000388107000031
ISSN: 1041-1135
eISSN: 1941-0174
第 23 条,共 261 条
标题: Investigations on the photoluminescence of the iron and cobalt doped fluoride-containing phosphate-based glasses and its defects-related nature
作者: He, QL (He, Quanlong); Wang, PF (Wang, Pengfei); Lu, M (Lu, Min); Peng, B (Peng, Bo)
来源出版物: JOURNAL OF ALLOYS AND COMPOUNDS 卷: 685 页: 153-158 DOI: 10.1016/j.jallcom.2016.05.253 出版年: NOV 15 2016
摘要: The influence of doping iron and cobalt ions on the formation of defects in the fluoride-containing phosphate-based glasses was studied comprehensively by means of analyzing the absorption and photoluminescence (PL) spectra as well as the electron spin resonance (ESR) spectra. The absorption and ESR spectra show that the defects, including phosphate-related oxygen hole center (POHC), oxygen-related hole centers (OHC), Fe3+, Co2+, PO3-EC, PO4-EC and fluorine-related non-paramagnetic color (FD) centers were formed during the glass preparation process. In addition, the analysis on the PL and absorption as well as excitation (PLE) spectra indicate that PO4-EC and OHC defects which have large absorption in the UV region result in the emission band peaking at 780 nm under the excitation at 351 nm for the cobalt doped (2 omega absorptive) glass. Addition of small quantities of iron causes the effectively intense absorption towards the 1 omega wavelength (1053 nm) due to the presence of Fe2+, but also a distinctively observed red-shift of the UV absorption edge was dominated by the charge-transfer transition of the existence of Fe3+. The experimental results demonstrate that Fe3+ suppress the formation of FD defects in the glasses, while promotes the formation of POHC defects. Besides, introduction of Co2+ inhibits the formation of POHC and PO4-EC defects, and Fe2+ promotes forming of POHC defects. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000382222300023
ISSN: 0925-8388
eISSN: 1873-4669
第 24 条,共 261 条
标题: Yb-doped large-mode-area aluminosilicate laser fibre fabricated by chelate precursor doping technique
作者: Peng, K (Peng, Kun); Wang, Z (Wang, Zhen); Zhan, H (Zhan, Huan); Ni, L (Ni, Li); Gao, C (Gao, Cong); Wang, XL (Wang, Xiaolong); Wang, YY (Wang, Yuying); Wang, JJ (Wang, Jianjun); Jing, F (Jing, Feng); Lin, AX (Lin, Aoxiang)
来源出版物: ELECTRONICS LETTERS 卷: 52 期: 23 页: 1942-U42 DOI: 10.1049/el.2016.3350 出版年: NOV 10 2016
摘要: A modified chelate precursor doping technique using high-purity materials and accurate gas flow control system is proposed to fabricate an efficient ytterbium-doped large-mode-area silica fibre for laser development. This technique enables to make homogeneous large-core preform with symmetrical shape, relatively low numerical aperture of approximate to 0.06 and large-core size of over 4 mm. Homemade preform was drawn into standard fibre for testing and fully characterised by electron probe microanalysis and time-of-flight secondary ion mass spectrometry. On the basis of two-stage master oscillator power amplifier system, 1 kW laser output with slope efficiency of 81.0% was realised at approximate to 1064 nm.
入藏号: WOS:000387576200025
ISSN: 0013-5194
eISSN: 1350-911X
第 25 条,共 261 条
标题: Pulse noise-hidden image reconstruction and visualization via stochastic resonance
作者: Sun, QB (Sun, Qibing); Liu, HJ (Liu, Hongjun); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu); Han, J (Han, Jing)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 36678 DOI: 10.1038/srep36678 出版年: NOV 8 2016
摘要: We investigate the nanosecond pulse noise-hidden image reconstruction and visualization using stochastic resonance implemented by modulation instability. In particular, this dynamical stochastic resonance holds with coupling between the pulse incoherent noise and pulse coherent signal, and provides a substantial enhancement of the signal-to-noise ratio and cross-correlation. This means that the pulse noise-hidden image can be effectively reconstructed with high visibility and fidelity via stochastic resonance at appropriate system parameters. Such a simple and convenient method has potential applications in image processing under noisy environment.
入藏号: WOS:000387324000001
PubMed ID: 27824152
ISSN: 2045-2322
第 26 条,共 261 条
标题: Action recognition by joint learning
作者: Yuan, Y (Yuan, Yuan); Qi, L (Qi, Lei); Lu, XQ (Lu, Xiaoqiang)
来源出版物: IMAGE AND VISION COMPUTING 卷: 55 特刊: SI 页: 77-85 DOI: 10.1016/j.imavis.2016.04.001 子辑: 2 出版年: NOV 2016
摘要: Due to the promising applications including video surveillance, video annotation, and interaction gaming, human action recognition from videos has attracted much research interest. Although various works have been proposed for human action recognition, there still exist many challenges such as illumination condition, viewpoint, camera motion and cluttered background. Extracting discriminative representation is one of the main ways to handle these challenges. In this paper, we propose a novel action recognition method that simultaneously learns middle-level representation and classifier by jointly training a multinomial logistic regression (MLR) model and a discriminative dictionary. In the proposed method, sparse code of low-level representation, conducting as latent variables of MLR, can capture the structure of low-level feature and thus is more discriminate. Meanwhile, the training of dictionary and MLR model are integrated into one objective function for considering the information of categories. By optimizing this objective function, we can learn a discriminative dictionary modulated by MLR and a MLR model driven by sparse coding. The proposed method is evaluated on YouTube action dataset and HMDB51 dataset. Experimental results demonstrate that our method is comparable with mainstream methods. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000389164300005
ISSN: 0262-8856
eISSN: 1872-8138
第 27 条,共 261 条
标题: Influence of Driving Frequency on the Argon Dielectric Barrier Discharge Excited by Gaussian Voltage at Atmospheric Pressure
作者: Xu, YG (Xu, Yonggang); Jiang, WM (Jiang, Weiman); Tang, J (Tang, Jie); Zhu, S (Zhu, Sha); Wang, YS (Wang, Yishan); Li, YF (Li, Yongfang); Zhao, W (Zhao, Wei); Duan, YX (Duan, Yixiang)
来源出版物: IEEE TRANSACTIONS ON PLASMA SCIENCE 卷: 44 期: 11 特刊: SI 页: 2553-2563 DOI: 10.1109/TPS.2016.2572733 子辑: 1 出版年: NOV 2016
摘要: A 1-D self-consistent fluid model was employed to investigate the effect of driving frequency on the discharge characters of a dielectric barrier discharge at atmospheric pressure in argon excited by a periodic Gaussian voltage. The simulation results indicate that there are two discharge modes: 1) Townsend and 2) glow modes in the multipulse discharge and different transitions between them during the discharge take place with the increase in driving frequency. When the driving frequency is 1 kHz, there is a tendency of transition from the Townsend mode through glow and finally back to the Townsend one during the positive half-circle of applied Gaussian voltage. However, the discharge in the half-circle can all along operate in the glow mode with the higher driving frequency. Moreover, when the driving frequency is sufficiently high, there are also distinct fluctuations of spatial performance of the charge densities in the positive column during the glow discharge. This is caused by the fact that a lot of charged particles created in the gas gap have not enough time to drift and diffuse to the dielectric barriers, and then these particles are preserved in the local discharge gap at such a high frequency. A comparison of the spatial and temporal evolutions of the electron density at different driving frequencies indicates that the increase in the driving frequency can enhance the plasma chemistry and also expand its volume.
入藏号: WOS:000388793800006
会议名称: 1st Sino-German Symposium on Atmospheric Pressure Gas Discharges and Plasma Applications
会议日期: OCT 11-17, 2015
会议地点: Sino German Sci Ctr, Beijing, PEOPLES R CHINA
会议赞助商 : German Res Fdn, Sino german Ctr, Nat Sci Fdn China
会议主办方: Sino German Sci Ctr
ISSN: 0093-3813
eISSN: 1939-9375
第 28 条,共 261 条
标题: Interference data correction methods for lunar observation with a large-aperture static imaging spectrometer
作者: Zhang, G (Zhang, Geng); Wang, S (Wang, Shuang); Li, LB (Li, Libo); Hu, XQ (Hu, Xiuqing); Hu, BL (Hu, Bingliang)
来源出版物: APPLIED OPTICS 卷: 55 期: 31 页: 8770-8778 DOI: 10.1364/AO.55.008770 出版年: NOV 1 2016
摘要: The lunar spectrum has been used in radiometric calibration and sensor stability monitoring for spaceborne optical sensors. A ground-based large-aperture static image spectrometer (LASIS) can be used to acquire the lunar spectral image for lunar radiance model improvement when the moon orbits over its viewing field. The lunar orbiting behavior is not consistent with the desired scanning speed and direction of LASIS. To correctly extract interferograms from the obtained data, a translation correction method based on image correlation is proposed. This method registers the frames to a reference frame to reduce accumulative errors. Furthermore, we propose a circle-matching-based approach to achieve even higher accuracy during observation of the full moon. To demonstrate the effectiveness of our approaches, experiments are run on true lunar observation data. The results show that the proposed approaches outperform the state-of-the-art methods. (C) 2016 Optical Society of America
入藏号: WOS:000387101100027
PubMed ID: 27828274
ISSN: 1559-128X
eISSN: 2155-3165
第 29 条,共 261 条
标题: Transmission volume phase holographic gratings in photo-thermo-refractive glass written with femtosecond laser Bessel beams
作者: Zhang, YJ (Zhang, Y. J.); Zhang, GD (Zhang, G. D.); Chen, CL (Chen, C. L.); Stoian, R (Stoian, R.); Cheng, GH (Cheng, G. H.)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 6 期: 11 页: 3491-3499 DOI: 10.1364/OME.6.003491 出版年: NOV 1 2016
摘要: Transmission volume phase holographic gratings were fabricated in bulk photo-thermo- refractive glass using zero-order femtosecond laser Bessel beams and subsequent thermal treatment. Microstructures composed of nano-sized crystals were observed in the exposed regions. The concentration of nano-crystals depended on the writing power, but the size of the nano-crystals was found to be quasi power-independent. Low writing power led to sparse nano-crystals, while optimized writing power achieved dense nano-crystals distribution and high refractive index change. Effects of the gratings thickness, writing laser power and thermal treatment on the diffraction efficiency were investigated. A maximum diffraction efficiency of 94.73% was achieved (at 532 nm testing wavelength) with 1 mm grating thickness at period of 5 mu m. (C) 2016 Optical Society of America
入藏号: WOS:000387562700014
ISSN: 2159-3930
第 30 条,共 261 条
标题: KW-level low photodarkening Yb/Ce codoped aluminosilicate fiber fabricated by the chelate gas phase deposition technique
作者: Zhang, LH (Zhang, Lihua); Li, G (Li, Gang); Li, WN (Li, Weinan); Gao, Q (Gao, Qi); Li, Z (Li, Zhe); Zhao, W (Zhao, Wei); Zhao, BY (Zhao, Baoyin); Hou, CQ (Hou, Chaoqi)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 6 期: 11 页: 3558-3564 DOI: 10.1364/OME.6.003558 出版年: NOV 1 2016
摘要: A Yb/Ce codoped aluminosilicate fiber was successfully fabricated by the chelate gas phase deposition technique. Using the homemade fiber as the amplifier stage in a master oscillator power amplifier configuration laser setup, a near single mode laser output (M-2 = 1.55) with an output power of 1026 W and slope efficiency of 84.8% is obtained. In the 100 hour photodarkening experiment, the entire reduced power is less than 14 W, and the ratio, compared to the initial 1026 W output power, is less than 1.4%. The investigation of optical properties indicates that Yb/Ce codoped aluminosilicate fiber fabricated by the chelate gas phase deposition technique shows homogenous distribution, appropriate absorption coefficient, low background attenuation, high optical-to-optical efficiency and a rather low photodarkening loss, making it a promising candidate as an active fiber for a reliable and efficient fiber laser in high-power applications. (C) 2016 Optical Society of America
入藏号: WOS:000387562700021
ISSN: 2159-3930
第 31 条,共 261 条
标题: Multiple Representations-Based Face Sketch-Photo Synthesis
作者: Peng, CL (Peng, Chunlei); Gao, XB (Gao, Xinbo); Wang, NN (Wang, Nannan); Tao, DC (Tao, Dacheng); Li, XL (Li, Xuelong); Li, J (Li, Jie)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 27 期: 11 页: 2201-2215 DOI: 10.1109/TNNLS.2015.2464681 出版年: NOV 2016
摘要: Face sketch-photo synthesis plays an important role in law enforcement and digital entertainment. Most of the existing methods only use pixel intensities as the feature. Since face images can be described using features from multiple aspects, this paper presents a novel multiple representations-based face sketch-photo-synthesis method that adaptively combines multiple representations to represent an image patch. In particular, it combines multiple features from face images processed using multiple filters and deploys Markov networks to exploit the interacting relationships between the neighboring image patches. The proposed framework could be solved using an alternating optimization strategy and it normally converges in only five outer iterations in the experiments. Our experimental results on the Chinese University of Hong Kong (CUHK) face sketch database, celebrity photos, CUHK Face Sketch FERET Database, IIIT-D Viewed Sketch Database, and forensic sketches demonstrate the effectiveness of our method for face sketch-photo synthesis. In addition, cross-database and database-dependent style-synthesis evaluations demonstrate the generalizability of this novel method and suggest promising solutions for face identification in forensic science.
入藏号: WOS:000386940300005
PubMed ID: 26357409
ISSN: 2162-237X
eISSN: 2162-2388
第 32 条,共 261 条
标题: Optically bound colloidal lattices in evanescent optical fields
作者: Han, X (Han, Xiang); Luo, H (Luo, Hui); Xiao, GZ (Xiao, Guangzong); Jones, PH (Jones, Philip H.)
来源出版物: OPTICS LETTERS 卷: 41 期: 21 页: 4935-4938 DOI: 10.1364/OL.41.004935 出版年: NOV 1 2016
摘要: In this Letter, we demonstrate the formation of a stable two-dimensional lattice of colloidal particles in the interference pattern formed by four evanescent optical fields at a dielectric interface. The microspheres are observed to form a two-dimensional square lattice with lattice vectors inclined relative to the beam propagation directions. We use digital video microscopy and particle tracking to measure the Brownian motion of particles bound in the lattice, and use this to characterize fluctuations in the local ordering of particles using the bond orientational order parameter, the probability distribution of which is shown to be a chi-squared distribution. An explanation for the form of this distribution is presented in terms of fluctuations of the modes of a ring of particles connected by springs. (C) 2016 Optical Society of America
入藏号: WOS:000386925800022
PubMed ID: 27805654
ISSN: 0146-9592
eISSN: 1539-4794
第 33 条,共 261 条
标题: Block Principal Component Analysis With Nongreedy l(1)-Norm Maximization
作者: Li, BN (Li, Bing Nan); Yu, Q (Yu, Qiang); Wang, R (Wang, Rong); Xiang, K (Xiang, Kui); Wang, M (Wang, Meng); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 11 页: 2543-2547 DOI: 10.1109/TCYB.2015.2479645 出版年: NOV 2016
摘要: Block principal component analysis with l(1)-norm (BPCA-L1) has demonstrated its effectiveness in a lot of visual classification and data mining tasks. However, the greedy strategy for solving the l(1)-norm maximization problem is prone to being struck in local solutions. In this paper, we propose a BPCA with nongreedy l(1)-norm maximization, which obtains better solutions than BPCA-L1 with all the projection directions optimized simultaneously. Other than BPCA-L1, the new algorithm has been evaluated against some popular principal component analysis (PCA) algorithms including PCA-L1 and 2-D PCA-L1 on a variety of benchmark data sets. The results demonstrate the effectiveness of the proposed method.
入藏号: WOS:000386227000013
PubMed ID: 26469852
作者识别号:
作者        ResearcherID 号        ORCID 号
LI, Bing Nan         E-7575-2010         0000-0002-4777-5773
ISSN: 2168-2267
eISSN: 2168-2275
第 34 条,共 261 条
标题: Simulation of the electron collection efficiency of a PMT based on the MCP coated with high secondary yield material
作者: Chen, L (Chen, Lin); Tian, JS (Tian, Jinshou); Zhao, TC (Zhao, Tianchi); Liu, CL (Liu, Chunliang); Liu, HL (Liu, Hulin); Wei, YL (Wei, Yonglin); Sai, XF (Sai, Xiaofeng); Chen, P (Chen, Ping); Wang, X (Wang, Xing); Lu, Y (Lu, Yu); Hui, DD (Hui, Dandan)
来源出版物: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 卷: 835 页: 94-98 DOI: 10.1016/j.nima.2016.08.034 出版年: NOV 1 2016
摘要: Owning to the serious loss of photoelectrons striking at the input electrode of traditional microchannel plate (MCP), photoelectron collection efficiency (CE) of photomultiplier tubes based on MCP (MCP-PMTs) fluctuates around the MCP open area fraction and cannot make a breakthrough. Depositing a thin film of high secondary electron yield material on the MCP is proposed as an effective approach to improve the CE. The available simulation and experimental data to validate it, however, is sparse. In our work, a three-dimensional small area MCP model is developed in CST Studio Suite to evaluate the collection efficiencies of PMTs based on the traditional MCP and the coated one, respectively. Results predict that CE of the PMT based on the coated MCP has a significant increase and a better uniformity, which is expected to reach 100%. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000386057800010
ISSN: 0168-9002
eISSN: 1872-9576
第 35 条,共 261 条
标题: Unsupervised 3D Local Feature Learning by Circle Convolutional Restricted Boltzmann Machine
作者: Han, ZZ (Han, Zhizhong); Liu, ZB (Liu, Zhenbao); Han, JW (Han, Junwei); Vong, CM (Vong, Chi-Man); Bu, SH (Bu, Shuhui); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 11 页: 5331-5344 DOI: 10.1109/TIP.2016.2605920 出版年: NOV 2016
摘要: Extracting local features from 3D shapes is an important and challenging task that usually requires carefully designed 3D shape descriptors. However, these descriptors are hand-crafted and require intensive human intervention with prior knowledge. To tackle this issue, we propose a novel deep learning model, namely circle convolutional restricted Boltzmann machine (CCRBM), for unsupervised 3D local feature learning. CCRBM is specially designed to learn from raw 3D representations. It effectively overcomes obstacles such as irregular vertex topology, orientation ambiguity on the 3D surface, and rigid or slightly non-rigid transformation invariance in the hierarchical learning of 3D data that cannot be resolved by the existing deep learning models. Specifically, by introducing the novel circle convolution, CCRBM holds a novel ring-like multi-layer structure to learn 3D local features in a structure preserving manner. Circle convolution convolves across 3D local regions via rotating a novel circular sector convolution window in a consistent circular direction. In the process of circle convolution, extra points are sampled in each 3D local region and projected onto the tangent plane of the center of the region. In this way, the projection distances in each sector window are employed to constitute a novel local raw 3D representation called projection distance distribution (PDD). In addition, to eliminate the initial location ambiguity of a sector window, the Fourier transform modulus is used to transform the PDD into the Fourier domain, which is then conveyed to CCRBM. Experiments using the learned local features are conducted on three aspects: global shape retrieval, partial shape retrieval, and shape correspondence. The experimental results show that the learned local features outperform other state-of-the-art 3D shape descriptors.
入藏号: WOS:000385380500001
ISSN: 1057-7149
eISSN: 1941-0042
第 36 条,共 261 条
标题: Watts-level super-compact narrow-linewidth Tm-doped silica all-fiber laser near 1707 nm with fiber Bragg gratings
作者: Xiao, XS (Xiao, X. S.); Guo, HT (Guo, H. T.); Lu, M (Lu, M.); Yan, ZJ (Yan, Z. J.); Wang, HS (Wang, H. S.); Wang, YS (Wang, Y. S.); Xu, YT (Xu, Y. T.); Gao, CX (Gao, C. X.); Cui, XX (Cui, X. X.); Guo, Q (Guo, Q.); Peng, B (Peng, B.)
来源出版物: LASER PHYSICS 卷: 26 期: 11 文献号: 115103 DOI: 10.1088/1054-660X/26/11/115103 出版年: NOV 2016
摘要: Watts-level ultra-short wavelength operation of a Tm-doped all fiber laser was developed by using a 1550 nm Er-doped fiber laser pump source and a pair of fiber Bragg gratings (FBGs). The laser yielded 1.28 W of continuous-wave output at 1707.01 nm with a narrow linewidth of similar to 44 pm by means of a 20 cm Tm-doped fiber. The dependencies of the slope efficiencies and pump threshold of the Tm-doped fiber laser versus the length of active fiber and reflectivity of the output mirror (FBG) were investigated in detail, in which the maximum average slope efficiency was 36.1%. There is no doubt that this all fiber laser will be a perfect pump source for mid-IR laser output.
入藏号: WOS:000385686900001
ISSN: 1054-660X
eISSN: 1555-6611
第 37 条,共 261 条
标题: A discriminative representation for human action recognition
作者: Yuan, Y (Yuan, Yuan); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang)
来源出版物: PATTERN RECOGNITION 卷: 59 特刊: SI 页: 88-97 DOI: 10.1016/j.patcog.2016.02.022 出版年: NOV 2016
摘要: Action recognition has been standing as an active research topic over the past years. Many efforts have been made and many methods have been proposed. However, there are still some challenges such as illumination condition, viewpoint, camera motion and cluttered background. In order to tackle these challenges, a discriminative representation is proposed by discovering key information of the input data. This task can be addressed by improvements of two major components: parameterized representation and discriminative classifier. The representation is parameterized with hidden variables and can be learned from training data. And the classifier can be trained to recognize actions based on the proposed representation. The contributions of this paper are as follows: (1) a novel probabilistic representation is utilized to capture the relative significant information of low level features; (2) a novel framework is proposed by combining the parameterized representation and discriminative classifier; (3) an alternating strategy is favorable to improve the performance of action recognition by updating the representation and the classifier alternatively. Experimental results on five well-known datasets demonstrate that the proposed method significantly improves the performance in action recognition. (C) 2016 Elsevier Ltd. All rights reserved.
入藏号: WOS:000383007800009
ISSN: 0031-3203
eISSN: 1873-5142
第 38 条,共 261 条
标题: Detection of Co-salient Objects by Looking Deep and Wide
作者: Zhang, DW (Zhang, Dingwen); Han, JW (Han, Junwei); Li, C (Li, Chao); Wang, JD (Wang, Jingdong); Li, XL (Li, Xuelong)
来源出版物: INTERNATIONAL JOURNAL OF COMPUTER VISION 卷: 120 期: 2 页: 215-232 DOI: 10.1007/s11263-016-0907-4 出版年: NOV 2016
摘要: In this paper, we propose a unified co-salient object detection framework by introducing two novel insights: (1) looking deep to transfer higher-level representations by using the convolutional neural network with additional adaptive layers could better reflect the sematic properties of the co-salient objects; (2) looking wide to take advantage of the visually similar neighbors from other image groups could effectively suppress the influence of the common background regions. The wide and deep information are explored for the object proposal windows extracted in each image. The window-level co-saliency scores are calculated by integrating the intra-image contrast, the intra-group consistency, and the inter-group separability via a principled Bayesian formulation and are then converted to the superpixel-level co-saliency maps through a foreground region agreement strategy. Comprehensive experiments on two existing and one newly established datasets have demonstrated the consistent performance gain of the proposed approach.
入藏号: WOS:000382092900006
作者识别号:
作者        ResearcherID 号        ORCID 号
zhang, dingwen         S-9447-2017         0000-0001-8369-8886
ISSN: 0920-5691
eISSN: 1573-1405
第 39 条,共 261 条
标题: Growth of SiC nanowires by low pressure chemical vapor infiltration using different catalysts
作者: Men, J (Men, Jing); Liu, YS (Liu, Yongsheng); Luo, R (Luo, Rong); Li, WN (Li, Weinan); Cheng, LF (Cheng, Laifei); Zhang, LT (Zhang, Litong)
来源出版物: JOURNAL OF THE EUROPEAN CERAMIC SOCIETY 卷: 36 期: 15 特刊: SI 页: 3615-3625 DOI: 10.1016/j.jeurceramsoc.2016.04.004 出版年: NOV 2016
摘要: SiC nanowires were synthesized by LPCVI using different catalysts, and the influences of input gas ratio (alpha) and catalysts were investigated. The average diameter firstly decreased and then increased with increasing alpha. Under Ni-based catalysis, SiC nanowires were long and thin, and increased with increasing concentration; under Fe-based catalysis, they were short and thick, and the influence of concentration could be neglected. The growth of SiC nanowires was controlled by vapor-liquid-solid (VLS) growth mechanism and the liquid-solid interface between nanowire and metal droplet was the growth plane. At same concentration, the diameter grown under Ni-based catalyst decreased with decreasing diameter of catalyst droplet, while under Fe-based catalyst, the diameters were not affected by catalyst droplet because of the high concentration. SiC nanowires were synthesized in 2D C/SiC composites and could enhance the mechanical properties effectively because of energy consuming from the fracture, pulled up and debond of SiC nanowires. (C) 2016 Elsevier Ltd. All rights reserved.
入藏号: WOS:000381951200009
会议名称: 1st Sino-German Symposium on Preparation and Application of Ultra-High Temperature Ceramic Matrix Composites
会议日期: JUL 26-31, 2015
会议地点: Darmstadt, GERMANY
会议赞助商 : Tech Univ Darmstadt, Sino German Ctr Res Promot
ISSN: 0955-2219
eISSN: 1873-619X
第 40 条,共 261 条
标题: Optical waveguides in magneto-optical glasses fabricated by proton implantation
作者: Liu, CX (Liu, Chun-Xiao); Li, YW (Li, Yu-Wen); Zheng, RL (Zheng, Rui-Lin); Fu, LL (Fu, Li-Li); Zhang, LL (Zhang, Liao-Lin); Guo, HT (Guo, Hai-Tao); Zhou, ZG (Zhou, Zhi-Guang); Li, WN (Li, Wei-Nan); Lin, SB (Lin, She-Bao); Wei, W (Wei, Wei)
来源出版物: OPTICS AND LASER TECHNOLOGY 卷: 85 页: 55-59 DOI: 10.1016/j.optlastec.2016.05.008 出版年: NOV 2016
摘要: Planar waveguides in magneto-optical glasses (Tb3+-doped aluminum borosilicate glasses) have been produced by a 550-keV proton implantation at a dose of 4.0 x 10(16) ions/cm(2) for the first time to our knowledge. After annealing at 260 degrees C for 1.0 h, the dark-mode spectra and near-field intensity distributions are measured by the prism-coupling and end-face coupling methods. The damage profile, refractive index distribution and light propagation mode of the planar waveguide are numerically calculated by SRIM 2010, RCM and FD-BPM, respectively. The effects of implantation on the structural and optical properties are investigated by Raman and absorption spectra. It suggests that the proton-implanted Tb3+-doped aluminum borosilicate glass waveguide is a good candidate for a waveguide isolator in optical fiber communication and all-optical communication. (C) 2016 Elsevier Ltd. All rights reserved.
入藏号: WOS:000380597200009
ISSN: 0030-3992
eISSN: 1879-2545
第 41 条,共 261 条
标题: Discrete bisoliton fiber laser
作者: Liu, XM (Liu, X. M.); Han, XX (Han, X. X.); Yao, XK (Yao, X. K.)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 34414 DOI: 10.1038/srep34414 出版年: OCT 21 2016
摘要: Dissipative solitons, which result from the intricate balance between dispersion and nonlinearity as well as gain and loss, are of the fundamental scientific interest and numerous important applications. Here, we report a fiber laser that generates bisoliton - two consecutive dissipative solitons that preserve a fixed separation between them. Deviations from this separation result in its restoration. It is also found that these bisolitons have multiple discrete equilibrium distances with the quantized separations, as is confirmed by the theoretical analysis and the experimental observations. The main feature of our laser is the anomalous dispersion that is increased by an order of magnitude in comparison to previous studies. Then the spectral filtering effect plays a significant role in pulse-shaping. The proposed laser has the potential applications in optical communications and high-resolution optics for coding and transmission of information in higher-level modulation formats.
入藏号: WOS:000385821900001
PubMed ID: 27767075
ISSN: 2045-2322
第 42 条,共 261 条
标题: Dispersion engineering of a As2Se3-based strip/slot hybrid waveguide for mid-infrared broadband wavelength conversion
作者: Hui, ZQ (Hui, Zhanqiang); Zhang, LX (Zhang, Lingxuan); Wang, LR (Wang, Leiran); Zhang, WF (Zhang, Wenfu)
来源出版物: MODERN PHYSICS LETTERS B 卷: 30 期: 28 文献号: 1650336 DOI: 10.1142/S021798491650336X 出版年: OCT 20 2016
摘要: An arsenic tri-selenide-based strip/slot hybrid waveguide with a single horizontal silica slot is proposed to achieve an extremely low and flat dispersion with three zero dispersion wavelengths. By adjusting the geometrical structural parameters of the hybrid waveguide, dispersion tailoring is fully obtained. The flat group velocity dispersion varying between +/- 0.08 ps(2)/(m) is obtained over a 1253 nm bandwidth. The parameters of effective area, nonlinear coefficient, and third-order dispersion are all investigated. Moreover, a compact on-chip all-optical wavelength converter is designed based on degenerate four-wave mixing in this waveguide. The dependencies of conversion efficiency and conversion bandwidth on the pump wavelength are discussed. The impact of pump power and signal power on the conversion efficiency is also investigated. The results show that a maximal conversion efficiency of 0.46 dB, and a 3-dB conversion bandwidth of 830 nm in the mid-infrared is achieved.
入藏号: WOS:000386671500005
ISSN: 0217-9849
eISSN: 1793-6640
第 43 条,共 261 条
标题: Slow light and fast light in microfiber double-knot resonator with a parallel structure
作者: Xu, YP (Xu, Yiping); Ren, LY (Ren, Liyong); Ma, CJ (Ma, Chengju); Kong, XD (Kong, Xudong); Ren, KL (Ren, Kaili)
来源出版物: APPLIED OPTICS 卷: 55 期: 30 页: 8612-8617 DOI: 10.1364/AO.55.008612 出版年: OCT 20 2016
摘要: Based on the theoretical model of a microfiber double-knot resonator with a parallel structure, numerical simulations on the transmission spectrum, the phase, and the group time delay of the resonator as a function of wavelengths are given. We find that with this kind of resonator both slow light and fast light can be obtained at different resonant wavelengths. Experimentally, such a kind of microfiber resonator was fabricated successfully. The transmission spectrum of the fabricated resonator is well consistent with the theoretical simulation. A slow-light delay of about 38 ps and a fast-light advance of about 40 ps are demonstrated at different wavelengths, which might benefit the resonator to the applications in data delay lines, optical buffers, and optical memories. (C) 2016 Optical Society of America
入藏号: WOS:000385717100032
PubMed ID: 27828144
作者识别号:
作者        ResearcherID 号        ORCID 号
Ren, Liyong         F-5518-2014         0000-0002-7547-7511
ISSN: 1559-128X
eISSN: 2155-3165
第 44 条,共 261 条
标题: Polarimetric dehazing method for visibility improvement based on visible and infrared image fusion
作者: Liang, J (Liang, Jian); Zhang, WF (Zhang, Wenfei); Ren, LY (Ren, Liyong); Ju, HJ (Ju, Haijuan); Qu, ES (Qu, Enshi)
来源出版物: APPLIED OPTICS 卷: 55 期: 29 页: 8221-8226 DOI: 10.1364/AO.55.008221 出版年: OCT 10 2016
摘要: Polarimetric dehazing methods have proven effective in enhancing the quality of chromatic hazy images. Considering that the infrared radiance has a better capacity for traveling through the haze, in this paper we propose a polarimetric dehazing method based on visible and infrared image fusion to improve the visibility of hazy images, especially for dense haze conditions. Experimental results demonstrate that the visibility of hazy images can be effectively enhanced, and the color information can be finely maintained. The visibility of dehazed images can be promoted at least 100%. This kind of dehazing method can be used widely in many dehazing applications. (C) 2016 Optical Society of America
入藏号: WOS:000385715900013
PubMed ID: 27828066
作者识别号:
作者        ResearcherID 号        ORCID 号
Ren, Liyong         F-5518-2014         0000-0002-7547-7511
ISSN: 1559-128X
eISSN: 2155-3165
第 45 条,共 261 条
标题: Projective robust nonnegative factorization
作者: Lu, YW (Lu, Yuwu); Lai, ZH (Lai, Zhihui); Xu, Y (Xu, Yong); You, J (You, Jane); Li, XL (Li, Xuelong); Yuan, C (Yuan, Chun)
来源出版物: INFORMATION SCIENCES 卷: 364 页: 16-32 DOI: 10.1016/j.ins.2016.05.001 出版年: OCT 10 2016
摘要: Nonnegative matrix factorization (NMF) has been successfully used in many fields as a low-dimensional representation method. Projective nonnegative matrix factorization (PNMF) is a variant of NMF that was proposed to learn a subspace for feature extraction. However, both original NMF and PNMF are sensitive to noise and are unsuitable for feature extraction if data is grossly corrupted. In order to improve the robustness of NMF, a framework named Projective Robust Nonnegative Factorization (PRNF) is proposed in this paper for robust image feature extraction and classification. Since learned projections can weaken noise disturbances, PRNF is more suitable for classification and feature extraction. In order to preserve the geometrical structure of original data, PRNF introduces a graph regularization term which encodes geometrical structure. In the PRNF framework, three algorithms are proposed that add a sparsity constraint on the noise matrix based on L-1/2 norm, L-1 norm, and L-2,L-1 norm, respectively. Robustness and classification performance of the three proposed algorithms are verified with experiments on four face image databases and results are compared with state-of-the-art robust NMF-based algorithms. Experimental results demonstrate the robustness and effectiveness of the algorithms for image classification and feature extraction. (C) 2016 Elsevier Inc. All rights reserved.
入藏号: WOS:000378969400002
作者识别号:
作者        ResearcherID 号        ORCID 号
You, Jane                  0000-0002-8181-4836
ISSN: 0020-0255
eISSN: 1872-6291
第 46 条,共 261 条
标题: Hierarchical learning of large-margin metrics for large-scale image classification
作者: Lei, H (Lei, Hao); Mei, KZ (Mei, Kuizhi); Xin, JM (Xin, Jingmin); Dong, PX (Dong, Peixiang); Fan, JP (Fan, Jianping)
来源出版物: NEUROCOMPUTING 卷: 208 特刊: SI 页: 46-58 DOI: 10.1016/j.neucom.2016.01.100 出版年: OCT 5 2016
摘要: Large-scale image classification is a challenging task and has recently attracted active research interests. In this paper, a new algorithm is developed to achieve more effective implementation of large-scale image classification by hierarchical learning of large-margin metrics (HLMMs). A hierarchical visual tree is seamlessly integrated with metric learning to learn a set of node-specific/category-specific large margin metrics. First, a hierarchical visual tree is learned to characterize the inter-category visual correlations effectively and organize large numbers of image categories in a coarse-to-fine fashion. Second, a new algorithm is developed to support hierarchical learning of large-margin metrics by training nearest class mean (NCM) classifiers over our hierarchical visual tree. In addition, we also consider dimensionality reduction as a regularizer for high-dimensional data in our large-margin metric learning. Two top down approaches are developed for supporting hierarchical learning of large-margin metrics. We focus on learning more discriminative metrics for NCM node classifiers to identify the visually similar sub nodes (visually similar image categories) under the same parent node over our hierarchical visual tree. A mini-batch stochastic gradient descend method is used to optimize our HLMMs learning algorithm. The experimental results on ImageNet Large Scale Visual Recognition Challenge 2010 dataset (ILSVRC2010) have demonstrated that our HLMMs learning algorithm is very promising for supporting large-scale image classification. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000382794300005
ISSN: 0925-2312
eISSN: 1872-8286
第 47 条,共 261 条
标题: 50 mu J Femtosecond Laser System Based on Strictly All-Fiber CPA Structure
作者: Li, F (Li, Feng); Yang, Z (Yang, Zhi); Zhao, W (Zhao, Wei); Li, QL (Li, Qianglong); Zhang, X (Zhang, Xin); Yang, XJ (Yang, Xiaojun); Zhang, W (Zhang, Wei); Wang, YS (Wang, Yishan)
来源出版物: IEEE PHOTONICS JOURNAL 卷: 8 期: 5 文献号: 1504206 DOI: 10.1109/JPHOT.2016.2614600 出版年: OCT 2016
摘要: We demonstrate a strictly all-polarization maintaining, all-fiber chirped pulse amplification of ultrashort pulses. Pulses with the duration of 933 fs and energy as high as 50 mu J are achieved at 200 kHz repetition rate in a compact size. The variations of the spectra and pulse widths as functions of the amplified output power have also been presented. To our best knowledge, this is the highest energy extracted from the strictly all-fiber chirped pulse amplification system. The environmentally stable femtosecond laser source will find various applications in practice.
入藏号: WOS:000401156100001
作者识别号:
作者        ResearcherID 号        ORCID 号
Feng, Li                  0000-0003-0846-7273
ISSN: 1943-0655
eISSN: 1943-0647
第 48 条,共 261 条
标题: Speckle phase retrieval and transmission matrix obtaining of turbid media
作者: Zhou, LB (Zhou, Libin); Zhuang, B (Zhuang, Bin); Sun, H (Sun, Hao); He, ZQ (He, Zhengquan); Hu, ML (Hu, Manli); Qiao, XG (Qiao, Xueguang)
来源出版物: OPTIK 卷: 127 期: 20 页: 9911-9916 DOI: 10.1016/j.ijleo.2016.07.091 出版年: OCT 2016
摘要: Previous research has demonstrated that distorted images caused by turbid media can be reconstructed by turbid lens imaging (TLI) method. In this way, it's critical to accurately obtain the transmission matrix (TM) of turbid media. In this letter, we propose an improved method which is still based on Hilbert transform to get the transmission matrices, but it will use four images for each transmission matrix element to eliminate the influence of speckle intensity variation. In addition, a Hanning window filter is introduced to reduce the white Gaussian noise of original images to improve the result of TLI method. (C) 2016 Elsevier GmbH. All rights reserved.
入藏号: WOS:000394632900091
ISSN: 0030-4026
第 49 条,共 261 条
标题: Bandwidth-tunable dissipative soliton and noise-like pulse in a. normal dispersion fiber laser with a. dual-scale saturable absorber
作者: Cui, YD (Cui, Yudong)
来源出版物: JOURNAL OF OPTICS 卷: 18 期: 10 文献号: 105503 DOI: 10.1088/2040-8978/18/10/105503 出版年: OCT 2016
摘要: A bandwidth-tunable dissipative soliton (DS) and noise-like pulse are demonstrated in an all-fiber normal dispersion fiber laser by employing a novel spectral filtering scheme. The mode locker is fabricated with a mixture composite that. combines the merits of graphene and carbon nanotubes. At a. pump power of 39 mW, a. DS with knife edges is generated at 1565 nm. One of the steep edges is induced by. gain spectral filtering and another is cut by a chirped fiber Bragg grating (CFBG). With higher pump power, the. noise-like pulse operation displays an asymmetric spectral profile, confirming the novel combined spectral filtering. When the CFBG is stretched mechanically, the bandwidth of the. DS and noise-like pulse can be tuned. The bandwidth-tunable mode-locked fiber laser has numerous potential applications, such as pulse shaping, as an. amplifier and in. optical nonlinear. investigations.
入藏号: WOS:000389843900001
ISSN: 2040-8978
eISSN: 2040-8986
第 50 条,共 261 条
标题: Photonics generation of frequency-shift keying radio-frequency signal using nonlinear polarization rotation in a highly nonlinear fiber
作者: Wang, X (Wang, Xin); Li, W (Li, Wei); Li, M (Li, Ming); Zhu, NH (Zhu, Ning Hua)
来源出版物: OPTICAL ENGINEERING 卷: 55 期: 10 文献号: 106118 DOI: 10.1117/1.OE.55.10.106118 出版年: OCT 2016
摘要: We experimentally demonstrate an all-optical approach for generating frequency-shift keying (FSK) radio-frequency (RF) signal based on nonlinear polarization rotation (NPR) in a highly nonlinear fiber (HNLF). A continuous wave probe beam is polarization-rotated by an optical amplitude-shift keying control beam via NPR in the HNLF. After removing the undesired control beam by a tunable optical filter, the polarization-rotated probe beam is converted to an intensity-modulated optical signal using a polarizer. By carefully adjusting the polarization controller before the polarizer and the optical power of the control beam, FSK RF signals are generated after photodetection. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000388233400047
ISSN: 0091-3286
eISSN: 1560-2303

 

第 51 条,共 261 条
标题: Pressure sensor based on the Sagnac effect and fiber loop ringdown spectroscopy
作者: Yang, SL (Yang, Songlin); Ruan, C (Ruan, Chi); Wang, YT (Wang, Yuntao)
来源出版物: OPTICAL ENGINEERING 卷: 55 期: 10 文献号: 107101 DOI: 10.1117/1.OE.55.10.107101 出版年: OCT 2016
摘要: A fiber-optic sensing scheme of measuring pressure is described here. The high reflective mirror in a laser cavity is replaced by a Sagnac loop in this scheme. The method combining the Sagnac effect with fiber loop ringdown technology fully embodies the advantages of both. The working principle is discussed in detail, and the whole sensing performance is demonstrated by applying sensing force to the sensor area. The sensing force can be obtained by measuring the ringdown time. The pressure measurement range of this device is 40 to 350 N. The detection sensitivity 0.4 ns/N can be realized in this system. The experimental curve reveals a close relationship between the sensing strain and the ringdown time. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000388233400057
ISSN: 0091-3286
eISSN: 1560-2303
第 52 条,共 261 条
标题: Waveguide Fabrication in Yb3+ Doped Phosphate Glass by 50 kHz Repetition Rate Ultrafast Laser
作者: Liu, X (Liu, Xin); Bai, J (Bai, Jing); Zhao, W (Zhao, Wei); Cheng, GH (Cheng, Guanghua)
来源出版物: JOURNAL OF LASER MICRO NANOENGINEERING 卷: 11 期: 3 页: 321-325 DOI: 10.2961/jlmn.2016.03.0007 出版年: OCT 2016
摘要: Waveguide (trace guiding type) inscription condition inside Yb3+ doped phosphate bulk glass was investigated under irradiating of 50 kHz repetition rate volume ultrafast lasers. We processed single trace and multi-core ones inside the bulk material, the captured near field mode pattern confirmed that both structures perform good guiding properties. Beam shaping technique was adopted during fabrication of the single trace in order to obtain a relative symmetric waveguide cross section. Waveguide lasing was achieved in the single line trace with a linear cavity configuration. The maximum laser output of 11 mW was obtained under mono-directional of 980 nm space light pumping, with similar to 2% corresponding slope efficiency. Guiding mode could be manipulated in the Expanded-core waveguide (ECW) by extra design freedom in the structure parameter, and ECW generally support larger effective mode area light transporting.
入藏号: WOS:000386652700007
ISSN: 1880-0688
第 53 条,共 261 条
标题: Initial Cumulative Effects in Femtosecond Pulsed Laser-induced Periodic Surface Structures on Bulk Metallic Glasses
作者: Li, C (Li, Chen); Zhang, H (Zhang, Hao); Cheng, GH (Cheng, Guanghua); Faure, N (Faure, Nicolas); Jamon, D (Jamon, Damien); Colombier, JP (Colombier, Jean-Philippe); Stoian, R (Stoian, Razvan)
来源出版物: JOURNAL OF LASER MICRO NANOENGINEERING 卷: 11 期: 3 页: 357-365 DOI: 10.2961/jlmn.2016.03.0014 出版年: OCT 2016
摘要: We investigate initial cumulative irradiation effects leading to variable surface topographies and nanoscale roughness, and triggering eventually the formation of laser-induced periodic surface structures (LIPSS) on Zr-based bulk metallic glasses (Zr41.2Ti13.8Cu12.5Ni10Be25.5 (at%)). We discuss interconnected aspects related to electronic excitation and optical transients, potential variations in the cartography of thermally-driven chemical modifications and topographical features assisting the surface coupling of the electromagnetic field. The transient optical properties of Zr-based BMG surfaces upon ultrafast irradiation, measured by a two-angle time-resolved single-pump doubleprobe ellipsometry method, show a remarkable constancy up to the point of optical damage and rapid gas-phase transition beyond. In intermediate and low exposure conditions, in the vicinity of the damage domain, multi-pulse incubation effects determine the appearance of nanoscale surface structures. The aspects discussed here involve primarily the progression of nanoscale structuring with an increasing number of fs laser pulses starting from a rough surface and evolving towards ordered corrugation. We emphasize the role of initial roughness in determining light coupling and the generation of regular stationary patterns of scattered light, localized energy absorption and spatially-variant ablation or modulated temperature-driven factors for surface relief. From a material perspective, energy dispersive X-ray spectrometry (EDX) analysis shows potential selective vaporization of light elements, leading to gradual compositional changes and proving a spatially-modulated temperature pattern. A formation scenario is proposed involving interference between the incident laser and scattered light potentially mediated by localized surface plasmons. Finitedifference time-domain (FDTD) simulations are applied to validate the mechanism, showing that LIPSS appear intrinsically related to the surface superposition of electromagnetic waves.
入藏号: WOS:000386652700014
作者识别号:
作者        ResearcherID 号        ORCID 号
Colombier, Jean-Philippe         B-8884-2012         0000-0001-8462-7019
ISSN: 1880-0688
第 54 条,共 261 条
标题: A Widely Tunable Photonic-Assisted Microwave Notch Filter with High Linearity Using a Dual-Parallel Mach-Zehnder Modulator
作者: Wang, X (Wang, Xin); Deng, Y (Deng, Ye); Wang, WT (Wang, Wen-Ting); Yuan, HQ (Yuan, Hai-Qing); Bai, JH (Bai, Jin-Hua); Liu, Y (Liu, Yu)
来源出版物: CHINESE PHYSICS LETTERS 卷: 33 期: 10 文献号: 104202 DOI: 10.1088/0256-307X/33/10/104202 出版年: OCT 2016
摘要: A widely tunable microwave photonic (MWP) notch filter with high linearity based on a dual-parallel Mach-Zehnder modulator (DPMZM) is proposed and experimentally demonstrated. The motivation of this work lies in the fact that the MWP notch filter previously reported has nonlinear distortions generally induced by the nonlinear property of electro-optic devices. In this scheme, even-order modulated sidebands at the DPMZM output are effectively suppressed by properly adjusting bias voltages of the DPMZM, which are the dominant factor to induce the nonlinear distortions into the MWP notch filter. The proposed scheme is theoretically analyzed and experimentally verified.
入藏号: WOS:000386125200015
ISSN: 0256-307X
eISSN: 1741-3540
第 55 条,共 261 条
标题: Space debris detection in optical image sequences
作者: Xi, JB (Xi, Jiangbo); Wen, DS (Wen, Desheng); Ersoy, OK (Ersoy, Okan K.); Yi, HW (Yi, Hongwei); Yao, DL (Yao, Dalei); Song, ZX (Song, Zongxi); Xi, SB (Xi, Shaobo)
来源出版物: APPLIED OPTICS 卷: 55 期: 28 页: 7929-7940 DOI: 10.1364/AO.55.007929 出版年: OCT 1 2016
摘要: We present a high-accuracy, low false-alarmrate, and low computational-cost methodology for removing stars and noise and detecting space debris with low signal-to-noise ratio (SNR) in optical image sequences. First, time-index filtering and bright star intensity enhancement are implemented to remove stars and noise effectively. Then, a multistage quasi-hypothesis-testing method is proposed to detect the pieces of space debris with continuous and discontinuous trajectories. For this purpose, a time-index image is defined and generated. Experimental results show that the proposed method can detect space debris effectively without any false alarms. When the SNR is higher than or equal to 1.5, the detection probability can reach 100%, and when the SNR is as low as 1.3, 1.2, and 1, it can still achieve 99%, 97%, and 85% detection probabilities, respectively. Additionally, two large sets of image sequences are tested to show that the proposed method performs stably and effectively. (C) 2016 Optical Society of America
入藏号: WOS:000385715100026
PubMed ID: 27828028
ISSN: 1559-128X
eISSN: 2155-3165
第 56 条,共 261 条
标题: Classifying Discriminative Features for Blur Detection
作者: Pang, YW (Pang, Yanwei); Zhu, HL (Zhu, Hailong); Li, XY (Li, Xinyu); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 10 页: 2220-2227 DOI: 10.1109/TCYB.2015.2472478 出版年: OCT 2016
摘要: Blur detection in a single image is challenging especially when the blur is spatially-varying. Developing discriminative blur features is an open problem. In this paper, we propose a new kernel-specific feature vector consisting of the information of a blur kernel and the information of an image patch. Specifically, the kernel specific-feature is composed of the multiplication of the variance of filtered kernel and the variance of filtered patch gradients. The feature origins from a blur-classification theorem and its discrimination can also be intuitively explained. To make the kernel-specific features useful for real applications, we build a pool of kernels consisting of motion-blur kernels, defocus-blur (out-of-focus) kernels, and their combinations. By extracting such features followed by the classifiers, the proposed algorithm outperforms the state-of-the-art blur detection method. Experimental results on public databases demonstrate the effectiveness of the proposed method.
入藏号: WOS:000384265600012
PubMed ID: 26357417
ISSN: 2168-2267
eISSN: 2168-2275
第 57 条,共 261 条
标题: Untitled
作者: Pei, J (Pei, Jian); Akoglu, L (Akoglu, Leman); Lee, H (Lee, Hongrae); Levandoski, J (Levandoski, Justin); Li, XL (Li, Xuelong); Meo, R (Meo, Rosa); Ordonez, C (Ordonez, Carlos); Phillips, J (Phillips, Jeff); Poblete, B (Poblete, Barbara); Candan, KS (Candan, K. Selcuk); Wang, M (Wang, Meng); Wen, JR (Wen, Ji-Rong); Xiong, L (Xiong, Li); Zhang, WJ (Zhang, Wenjie)
来源出版物: IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 卷: 28 期: 10 页: 2535-2537 DOI: 10.1109/TKDE.2016.2592658 出版年: OCT 1 2016
入藏号: WOS:000384236300001
作者识别号:
作者        ResearcherID 号        ORCID 号
Poblete, Barbara         G-3562-2016         
ISSN: 1041-4347
eISSN: 1558-2191
第 58 条,共 261 条
标题: Stable all-fiber Er-doped Q-switched laser with a WS2/fluorine mica (FM) saturable absorber
作者: Li, L (Li, Lu); Wang, ZF (Wang, ZhenFu); Wang, YG (Wang, Yonggang); Wang, X (Wang, Xi); Yang, GW (Yang, Guowen); Jiang, SZ (Jiang, Shouzhen)
来源出版物: LASER PHYSICS 卷: 26 期: 10 文献号: 105101 DOI: 10.1088/1054-660X/26/10/105101 出版年: OCT 2016
摘要: This paper presents a stable all-fiber Q-switched Er-doped fiber (EDF) laser with WS2/fluorine mica (FM) as the saturable absorber (SA). The SA device is obtained by depositing WS2 nanosheet layers onto a 20 mu m thick one-layer FM substrate using a thermal decomposition method. The modulation depth (MD) of the SA is 8.22% and the non-saturable loss (NL) is 16.38%. By inserting the SA into the EDF laser cavity, stable Q-switched operation is achieved with a central wavelength of 1567 nm. The repetition rate can be tuned from 20.98 kHz to 33.74 kHz and the pulse duration can be adjusted from 8.3 mu s to 6.98 mu s by increasing the pump power. The maximum output power and the maximum pulse energy are measured to be 2.07 mW and 61.4 nJ, respectively. The experimental results evidently show that the WS2/FM can be regarded as a high-performance SA for fiber lasers.
入藏号: WOS:000384179800001
ISSN: 1054-660X
eISSN: 1555-6611
第 59 条,共 261 条
标题: Polyfurfuryl alcohol spheres template synthesis of 3D porous graphene for high-performance supercapacitor application
作者: Ma, CL (Ma, Cunliang); Peng, L (Peng, Li); Feng, YF (Feng, Yafei); Shen, JX (Shen, Jiaxin); Xiao, ZQ (Xiao, Zhuangqing); Cai, KY (Cai, Kaiyu); Yu, YH (Yu, Youhai); Min, Y (Min, Yong); Epstein, AJ (Epstein, Arthur J.)
来源出版物: SYNTHETIC METALS 卷: 220 页: 227-235 DOI: 10.1016/j.synthmet.2016.06.008 出版年: OCT 2016
摘要: In this work, a 3D porous graphene (3DrGO) was prepared by a hydrothermal assembly process of graphene oxide (GO) using polyfurfuryl alcohol (PFA) spheres as the template followed by thermal reduction. The introduction of PFA spheres can effectively enlarge the interspace between graphene sheets and suppresses their re-stacking in the thermal treatment. The 3DrGO was further composted with PANI nanowire. The structure and the property of 3DrGO and 3DrGO/PANI composite have been characterized by transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, cyclic voltammetry, galvanostatic charge discharge test and electrochemical impedance spectroscopy. Electrochemical test reveals that the 3DrGO has good capacitance performance of 104 F/g at current charge-discharge current density of 1A/g and the capacitance performance increase to 530 F/g after further composed with PANI nanowire. Both 3DrGO and 3DrGO/PANI show excellent capacity retention rates of 95% and 88%, respectively, after 1000 cycles. All these impressive results demonstrate that the material obtained by this approach is greatly promising for application in high-performance supercapacitors. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000383811300029
作者识别号:
作者        ResearcherID 号        ORCID 号
Yu, Youhai                  0000-0002-6321-5100
ISSN: 0379-6779
第 60 条,共 261 条
标题: Effects of fluorine on the properties of Yb/Ce co-doped aluminosilicate preforms prepared by MCVD with organic chelate precursor doping technique
作者: Li, WN (Li, Weinan); Luo, R (Luo, Rong); Li, C (Li, Chao); Gao, S (Gao, Song); Chang, C (Chang, Chang); Hou, CQ (Hou, Chaoqi); Zhao, BY (Zhao, Baoyin)
来源出版物: JOURNAL OF NON-CRYSTALLINE SOLIDS 卷: 449 页: 119-124 DOI: 10.1016/j.jnoncrysol.2016.07.016 出版年: OCT 1 2016
摘要: Co-doped Yb/Ce aluminosilicate fiber preforms with less than 1 We% fluorine were prepared by MCVD with organic chelate precursor doping technique at 1400 degrees C. Fluorine content characterized by electron probe microanalysis decreased with increasing SiF4 flow and flow ratio of SiF4/SiCl4. Under maximum SiF4 flow the concentrations of Yb2O3 and CeO2 in the perform core were only as much as 17% and 25% under minimum SiF4 flow, respectively, but smaller refractive index change was only shown in fiber core. The reason was that the reaction of SiF4 with Al2O3,Yb2O3,CeO2 were intensified with increasing flow ratio of SiF4/SiCl4 and then resulted in producing more exhaust gas such as AlF3, YbF3 and CeF4. Raman spectra of core glasses with <0.5 Wt% fluorine present different Raman shifts from F doped silica glass with 1-3.3 Wt% fluorine: 945 cm(-1) of Si-F stretching bond was not observed, and with growth of fluorine content antisymmetric stretching vibrations of Si-O-Si linkages split from an envelope of 1188 cm(-1) into two peaks or three peaks shifted higher frequency. At the same time, Boson peak near 125 cm(-1) shifted to lower frequency. They were attributed to some minor changes of glass's network structure due to introducing lower fluorine into core glasses. On base of bonding energymeasured by X-ray photoelectric spectroscopy, the plane graph describing the complex bonding distribution with F in core was supplied to in order to illustrate network structure change. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000383298000017
ISSN: 0022-3093
eISSN: 1873-4812
第 61 条,共 261 条
标题: Video parsing via spatiotemporally analysis with images
作者: Li, XL (Li, Xuelong); Mou, LC (Mou, Lichao); Lu, XQ (Lu, Xiaoqiang)
来源出版物: MULTIMEDIA TOOLS AND APPLICATIONS 卷: 75 期: 19 页: 11961-11976 DOI: 10.1007/s11042-015-2735-x 出版年: OCT 2016
摘要: Effective parsing of video through the spatial and temporal domains is vital to many computer vision problems because it is helpful to automatically label objects in video instead of manual fashion, which is tedious. Some literatures propose to parse the semantic information on individual 2D images or individual video frames, however, these approaches only take use of the spatial information, ignore the temporal continuity information and fail to consider the relevance of frames. On the other hand, some approaches which only consider the spatial information attempt to propagate labels in the temporal domain for parsing the semantic information of the whole video, yet the non-injective and non-surjective natures can cause the black hole effect. In this paper, inspirited by some annotated image datasets (e.g., Stanford Background Dataset, LabelMe, and SIFT-FLOW), we propose to transfer or propagate such labels from images to videos. The proposed approach consists of three main stages: I) the posterior category probability density function (PDF) is learned by an algorithm which combines frame relevance and label propagation from images. II) the prior contextual constraint PDF on the map of pixel categories through whole video is learned by the Markov Random Fields (MRF). III) finally, based on both learned PDFs, the final parsing results are yielded up to the maximum a posterior (MAP) process which is computed via a very efficient graph-cut based integer optimization algorithm. The experiments show that the black hole effect can be effectively handled by the proposed approach.
入藏号: WOS:000382678200021
ISSN: 1380-7501
eISSN: 1573-7721
第 62 条,共 261 条
标题: A numerical algorithm to evaluate the transient response for a synchronous scanning streak camera using a time-domain Baum Liu Tesche equation
作者: Pei, CQ (Pei, Chengquan); Tian, JS (Tian, Jinshou); Wu, SL (Wu, Shengli); He, JA (He, Jiai); Liu, Z (Liu, Zhen)
来源出版物: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 卷: 832 页: 8-14 DOI: 10.1016/j.nima.2016.06.061 出版年: OCT 1 2016
摘要: The transient response is of great influence on the electromagnetic compatibility of synchronous scanning streak cameras (SSSCs). In this paper we propose a numerical method to evaluate the transient response of the scanning deflection plate (SDP). First, we created a simplified circuit model for the SDP used in an SSSC, and then derived the Baum-Liu-Tesche (BLT) equation in the frequency domain. From the frequency-domain BLT equation, its transient counterpart was derived. These parameters, together with the transient-BLT equation, were used to compute the transient load voltage and load current, and then a novel numerical method to fulfill the continuity equation was used. Several numerical simulations were conducted to verify this proposed method. The computed results were then compared with transient responses obtained by a frequency-domain/fast Fourier transform (FFT) method, and the accordance was excellent for highly conducting cables. The benefit of deriving the BLT equation in the time domain is that it may be used with slight modifications to calculate the transient response and the error can be controlled by a computer program. The result showed that the transient voltage was up to 1000 V and the transient current was approximately 10 A, so some protective measures should be taken to improve the electromagnetic compatibility. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000382256400002
ISSN: 0168-9002
eISSN: 1872-9576
第 63 条,共 261 条
标题: Local structure learning in high resolution remote sensing image retrieval
作者: Du, ZX (Du, Zhongxiang); Li, XL (Li, Xuelong); Lu, XQ (Lu, Xiaoqiang)
来源出版物: NEUROCOMPUTING 卷: 207 页: 813-822 DOI: 10.1016/j.neucom.2016.05.061 出版年: SEP 26 2016
摘要: High resolution remote sensing image captured by the satellites or the aircraft is of great help for military and civilian applications. In recent years, with an increasing amount of high-resolution remote sensing images, it becomes more and more urgent to find a way to retrieve them. In this case, a few methods based on the statistical-information of the local features are proposed, which have achieved good performances. However, most of the methods do not take the topological structure of the features into account. In this paper, we propose a new method to represent these images, by taking the structural information into consideration. The main contributions of this paper include: (1) mapping the features into a manifold space by a Lipschitz smooth function to enhance the representation ability of the features; (2) training an anchor set with several regularization constrains to get the intrinsic manifold structure. In the experiments, the method is applied to two challenging remote sensing image datasets: UC Merced land use dataset and Sydney dataset. Compared to the state-of-the-art approaches, the proposed method can achieve a more robust and commendable performance. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000382794500077
ISSN: 0925-2312
eISSN: 1872-8286
第 64 条,共 261 条
标题: Rough gold films as broadband absorbers for plasmonic enhancement of TiO2 photocurrent over 400-800 nm
作者: Tan, FR (Tan, Furui); Li, TH (Li, Tenghao); Wang, N (Wang, Ning); Lai, SK (Lai, Sin Ki); Tsoi, CC (Tsoi, Chi Chung); Yu, WX (Yu, Weixing); Zhang, XM (Zhang, Xuming)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 33049 DOI: 10.1038/srep33049 出版年: SEP 9 2016
摘要: Recent years have witnessed an increasing interest in highly-efficient absorbers of visible light for the conversion of solar energy into electrochemical energy. This study presents a TiO2-Au bilayer that consists of a rough Au film under a TiO2 film, which aims to enhance the photocurrent of TiO2 over the whole visible region and may be the first attempt to use rough Au films to sensitize TiO2. Experiments show that the bilayer structure gives the optimal optical and photoelectrochemical performance when the TiO2 layer is 30 nm thick and the Au film is 100 nm, measuring the absorption 80-90% over 400-800 nm and the photocurrent intensity of 15 mu A.cm(-2), much better than those of the TiO2-AuNP hybrid (i.e., Au nanoparticle covered by the TiO2 film) and the bare TiO2 film. The superior properties of the TiO2-Au bilayer can be attributed to the rough Au film as the plasmonic visible-light sensitizer and the photoactive TiO2 film as the electron accepter. As the Au film is fully covered by the TiO2 film, the TiO2-Au bilayer avoids the photocorrosion and leakage of Au materials and is expected to be stable for long-term operation, making it an excellent photoelectrode for the conversion of solar energy into electrochemical energy in the applications of water splitting, photocatalysis and photosynthesis.
入藏号: WOS:000382728000001
PubMed ID: 27608836
作者识别号:
作者        ResearcherID 号        ORCID 号
Yu, Weixing         G-3658-2012         0000-0002-3216-526X
Zhang, Xuming                  0000-0002-9326-5547
ISSN: 2045-2322
第 65 条,共 261 条
标题: Spinning and orbiting motion of particles in vortex beams with circular or radial polarizations
作者: Li, MM (Li, Manman); Yan, SH (Yan, Shaohui); Yao, BL (Yao, Baoli); Liang, YS (Liang, Yansheng); Zhang, P (Zhang, Peng)
来源出版物: OPTICS EXPRESS 卷: 24 期: 18 页: 20604-20612 DOI: 10.1364/OE.24.020604 出版年: SEP 5 2016
摘要: Focusing fields of optical vortex (OV) beams with circular or radial polarizations carry both spin angular momentum (SAM) and orbital angular momentum (OAM), and can realize non-axial spinning and orbiting motion of absorptive particles. Using the T-matrix method, we evaluate the optical forces and torques exerted on micro-sized particles induced by the OV beams. Numerical results demonstrate that the particle is trapped on the circle of intensity maxima, and experiences a transverse spin torque along azimuthal direction, a longitudinal spin torque, and an orbital torque, respectively. The direction of spinning motion is not only related to the sign of topological charge of the OV beam, but also to the polarization state. However, the topological charge controls the direction of orbiting motion individually. Optically induced rotations of particles with varying sizes and absorptivity are investigated in OV beams with different topological charges and polarization states. These results may be exploited in practical optical manipulation, especially for optically induced rotations of micro-particles. (C) 2016 Optical Society of America
入藏号: WOS:000386091300067
PubMed ID: 27607664
ISSN: 1094-4087
第 66 条,共 261 条
标题: SERF: A Simple, Effective, Robust, and Fast Image Super-Resolver From Cascaded Linear Regression
作者: Hu, YT (Hu, Yanting); Wang, NN (Wang, Nannan); Tao, DC (Tao, Dacheng); Gao, XB (Gao, Xinbo); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 9 页: 4091-4102 DOI: 10.1109/TIP.2016.2580942 出版年: SEP 2016
摘要: Example learning-based image super-resolution techniques estimate a high-resolution image from a low-resolution input image by relying on high-and low-resolution image pairs. An important issue for these techniques is how to model the relationship between high-and low-resolution image patches: most existing complex models either generalize hard to diverse natural images or require a lot of time for model training, while simple models have limited representation capability. In this paper, we propose a simple, effective, robust, and fast (SERF) image superresolver for image super-resolution. The proposed super-resolver is based on a series of linear least squares functions, namely, cascaded linear regression. It has few parameters to control the model and is thus able to robustly adapt to different image data sets and experimental settings. The linear least square functions lead to closed form solutions and therefore achieve computationally efficient implementations. To effectively decrease these gaps, we group image patches into clusters via k-means algorithm and learn a linear regressor for each cluster at each iteration. The cascaded learning process gradually decreases the gap of highfrequency detail between the estimated high-resolution image patch and the ground truth image patch and simultaneously obtains the linear regression parameters. Experimental results show that the proposed method achieves superior performance with lower time consumption than the state-of-the-art methods.
入藏号: WOS:000397743400001
PubMed ID: 27323364
ISSN: 1057-7149
eISSN: 1941-0042
第 67 条,共 261 条
标题: Relay Selection for Wireless Communications against Eavesdropping: A Security-Reliability Trade-off Perspective
作者: Zou, YL (Zou, Yulong); Zhu, J (Zhu, Jia); Li, XL (Li, Xuelong); Hanzo, L (Hanzo, Lajos)
来源出版物: IEEE NETWORK 卷: 30 期: 5 页: 74-79 出版年: SEP-OCT 2016
摘要: This article examines secrecy coding aided wireless communications from a source to a destination in the presence of an eavesdropper from an SRT perspective. Explicitly, security is quantified in terms of the intercept probability experienced at the eavesdropper, while the outage probability encountered at the destination is used to measure transmission reliability. We characterize the SRT of conventional direct transmission from the source to the destination and show that if the outage probability is increased, the intercept probability decreases, and vice versa. We first demonstrate that the employment of relay nodes for assisting source-destination transmission is capable of defending against eavesdropping, followed by quantifying the benefits of SRS as well as MRS schemes. More specifically, in the SRS scheme, only the single "best" relay is selected for forwarding the source signal to the destination, whereas the MRS scheme allows multiple relays to participate in this process. It is illustrated that both the SRS and MRS schemes achieve a better SRT than conventional direct transmission, especially upon increasing the number of relays. Numerical results also show that, as expected, MRS outperforms SRS in terms of its SRT. Additionally, we present some open challenges and future directions for wireless relay aided physical-layer security.
入藏号: WOS:000389893300012
作者识别号:
作者        ResearcherID 号        ORCID 号
Hanzo, Lajos                  0000-0002-2636-5214
ISSN: 0890-8044
eISSN: 1558-156X
第 68 条,共 261 条
标题: Two side liquid-cooled and passively Q-switched disk oscillator with nanosheets in flowing CCl4
作者: Nie, RZ (Nie, Rongzhi); She, JB (She, Jiangbo); Li, DD (Li, Dongdong); Li, FL (Li, Fuli); Peng, B (Peng, Bo)
来源出版物: APPLIED PHYSICS B-LASERS AND OPTICS 卷: 122 期: 9 文献号: 241 DOI: 10.1007/s00340-016-6519-4 出版年: SEP 2016
摘要: A passively Q-switched and two side liquid-cooled Nd:YAG disk oscillator is demonstrated, which is operated at a pump pulse width of 300 mu s and a pump repetition rate of 10 Hz. The coolant flows over the two large surfaces of the disk and will be passed through by laser beam, so it can also serve as a saturable absorber. For the unmodulated laser, the pure CCl4 was employed as coolant and a plane output mirror of 15 % transmission was employed. The maximum output energy of 795 mJ is realized corresponding to the optical-optical efficiency of 27.4 % and the slope efficiency of 30 %; for the graphene Q-switched laser, the CCl4 with graphene nanosheets was employed as coolant and a plane output mirror of 40 % transmission was employed. The maximum output energy of 376 mJ is realized corresponding to the optical-optical efficiency of 13 % and the slope efficiency of 18 %. The maximum average Q-switching repetition rate is 385 kHz, and the minimum average pulse width is 116 ns; for the MoS2 Q-switched laser, the CCl4 with MoS2 nanosheets was employed as coolant and a plane output mirror of 30 % transmission was employed. The maximum output energy of 486 mJ is realized corresponding to the optical-optical efficiency of 17 % and the slope efficiency of 22 %. The maximum average Q-switching repetition rate is 470 kHz, and the minimum average pulse width is 137 ns.
入藏号: WOS:000383609500011
ISSN: 0946-2171
eISSN: 1432-0649
第 69 条,共 261 条
标题: Image recombination transform algorithm for superresolution structured illumination microscopy
作者: Zhou, X (Zhou, Xing); Lei, M (Lei, Ming); Dan, D (Dan, Dan); Yao, BL (Yao, Baoli); Yang, YL (Yang, Yanlong); Qian, J (Qian, Jia); Chen, GD (Chen, Guangde); Bianco, PR (Bianco, Piero R.)
来源出版物: JOURNAL OF BIOMEDICAL OPTICS 卷: 21 期: 9 文献号: 096009 DOI: 10.1117/1.JBO.21.9.096009 出版年: SEP 2016
摘要: Structured illumination microscopy (SIM) is an attractive choice for fast superresolution imaging. The generation of structured illumination patterns made by interference of laser beams is broadly employed to obtain high modulation depth of patterns, while the polarizations of the laser beams must be elaborately controlled to guarantee the high contrast of interference intensity, which brings a more complex configuration for the polarization control. The emerging pattern projection strategy is much more compact, but the modulation depth of patterns is deteriorated by the optical transfer function of the optical system, especially in high spatial frequency near the diffraction limit. Therefore, the traditional superresolution reconstruction algorithm for interference-based SIM will suffer from many artifacts in the case of projection-based SIM that possesses a low modulation depth. Here, we propose an alternative reconstruction algorithm based on image recombination transform, which provides an alternative solution to address this problem even in a weak modulation depth. We demonstrated the effectiveness of this algorithm in the multicolor superresolution imaging of bovine pulmonary arterial endothelial cells in our developed projection-based SIM system, which applies a computer controlled digital micromirror device for fast fringe generation and multicolor light-emitting diodes for illumination. The merit of the system incorporated with the proposed algorithm allows for a low excitation intensity fluorescence imaging even less than 1 W/cm(2), which is beneficial for the long-term, in vivo superresolved imaging of live cells and tissues. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License.
入藏号: WOS:000388212700040
PubMed ID: 27653935
ISSN: 1083-3668
eISSN: 1560-2281
第 70 条,共 261 条
标题: Improvement of CO2 capture performance of calcium-based absorbent modified with palygorskite
作者: Shan, LY (Shan, Liyuan); Li, H (Li, Hui); Meng, BL (Meng, Binglu); Yu, YH (Yu, Youhai); Min, YG (Min, Yonggang)
来源出版物: CHINESE JOURNAL OF CHEMICAL ENGINEERING 卷: 24 期: 9 页: 1283-1289 DOI: 10.1016/j.cjche.2016.05.021 出版年: SEP 2016
摘要: Limestone can be used for CO2 capture and sequestration (CCS) in flue gas effectively. However, its CCS capability will dramatically decline after several cycles due to the surface "sintering". In this work, the limestone was modified with palygorskite to reduce sintering phenomenon between the absorbent particles during the CCS process and the carbonation rate of the limestone can be enhanced effectively. Palygorskite is a natural mineral with nano-fibrous structure which can reduce the mutual contact of limestone particles during the CCS process. The results were detected by TGA, SEM, MIP, FTIR and particle size analyzer respectively. The best CO2 capture performance of modified absorbent was 13.11% improvement with only 5 wt% palygorskite added during the CCS process after 15 cycles compared with natural absorbent. It was found that excellent microscopic structures of absorbent modified with palygorskite was created, and the surface sintering was postponed leading to CO2 capture performance enhanced under the same conditions. (C) 2016 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.
入藏号: WOS:000387583600021
ISSN: 1004-9541
eISSN: 2210-321X
第 71 条,共 261 条
标题: Ultrafast optical beam deflection in a pump probe configuration
作者: Liang, LL (Liang, Lingliang); Tian, JS (Tian, Jinshou); Wang, T (Wang, Tao); Wu, SL (Wu, Shengli); Li, FL (Li, Fuli); Wang, JF (Wang, Junfeng); Gao, GL (Gao, Guilong)
来源出版物: CHINESE PHYSICS B 卷: 25 期: 9 文献号: 090602 DOI: 10.1088/1674-1056/25/9/090602 出版年: SEP 2016
摘要: Propagation of a signal beam in an AlGaAs/GaAs waveguide multiple-prism light deflector is theoretically investigated by solving the scalar Helmholtz equation to obtain the dependences of the temporal and spatial resolvable characteristics of the ultrafast deflector on the material dispersion of GaAs including group velocity dispersion and angular dispersion, interface reflection, and interface scattering of multiple-prism deflector. Furthermore, we experimentally confirm that, in this ultrafast beam deflection device, the deflecting angle of the signal light beam is linear with the pump fluence and the temporal resolution of the ultrafast deflection is 10 ps. Our results show that the improvement of the temporal and spatial resolvable performances is possible by properly choosing the structural parameters and enhancing the quality of the device.
入藏号: WOS:000384226500016
ISSN: 1674-1056
eISSN: 1741-4199
第 72 条,共 261 条
标题: Motion Blur Detection With an Indicator Function for Surveillance Machines
作者: Pang, YW (Pang, Yanwei); Zhu, HL (Zhu, Hailong); Li, XL (Li, Xuelong); Pan, J (Pan, Jing)
来源出版物: IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 卷: 63 期: 9 页: 5592-5601 DOI: 10.1109/TIE.2016.2564938 出版年: SEP 2016
摘要: Motion is an important clue for industrial inspection, video surveillance, and service machines to localize and recognize products and objects. Because blur co-occurs with motion, it is desirable for developing efficient and robust motion blur detection algorithm. However, existing algorithms are inefficient for detecting spatially varying motion blur. To deal with the problem, this paper presents a theorem, according to which, motion blur can be efficiently detected and segmented. According to the theorem, the proposed algorithm requires a simple filtering operation and variance computation. Classification as either blurred or unblurred pixel can be done by substituting the variance into the proposed simple formula and checking the sign of the resulting value. Moreover, a geometric interpretation and two extensions of the algorithm are given. Importantly, based on the geometric interpretation of the indicator function, we develop a one-class classifier, which is more effective than the indicator function and has comparable computational cost of the indicator function. Experimental results on detecting motion-blurred cars, motorcycles, bicycles, bags, and persons demonstrate that the proposed algorithm is very efficient without loss of effectiveness.
入藏号: WOS:000384641600029
ISSN: 0278-0046
eISSN: 1557-9948
第 73 条,共 261 条
标题: 3D object hiding using three-dimensional ptychography
作者: Zhang, J (Zhang, Jun); Wang, ZB (Wang, Zhibo); Li, T (Li, Tuo); Pan, A (Pan, An); Wang, YL (Wang, Yali); Shi, YS (Shi, Yishi)
来源出版物: JOURNAL OF OPTICS 卷: 18 期: 9 文献号: 095701 DOI: 10.1088/2040-8978/18/9/095701 出版年: SEP 2016
摘要: We present a novel technique for 3D object hiding by applying three-dimensional ptychography. Compared with 3D information hiding based on holography, the proposed ptychography-based hiding technique is easier to implement, because the reference beam and high-precision interferometric optical setup are not required. The acquisition of the 3D object and the ptychographic encoding process are performed optically. Owing to the introduction of probe keys, the security of the ptychography-based hiding system is significantly enhanced. A series of experiments and simulations demonstrate the feasibility and imperceptibility of the proposed method.
入藏号: WOS:000384148200001
ISSN: 2040-8978
eISSN: 2040-8986
第 74 条,共 261 条
标题: A Novel Spatial-Spectral Sparse Representation for Hyperspectral Image Classification Based on Neighborhood Segmentation
作者: Wang, CL (Wang Cai-ling); Wang, HW (Wang Hong-wei); Hu, BL (Hu Bing-liang); Wen, J (Wen Jia); Xu, J (Xu Jun); Li, XJ (Li Xiang-juan)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 36 期: 9 页: 2919-2924 DOI: 10.3964/j.issn.1000-0593(2016)09-2919-06 出版年: SEP 2016
摘要: Traditional hyperspectral image classification algorithms focus on spectral' information application, however, with the increase of spatial resolution of hyperspectral remote sensing images, hyperspectral imaging presents clustering properties on spatial domain for the same category. It is critical for hyperspectral image classification algorithms to use spatial information in order to improve the classification accuracy. However, the marginal differences of different categories display more obviously. If it is introduced directly into the spatial-spectral sparse representation for image classification without the selection of neighborhood pixels, the classification error and the computation time will increase. This paper presents a spatial-spectral joint sparse representation classification algorithm based on neighborhood segmentation. The algorithm calculates the similarity with spectral angel in order to choose proper neighborhood pixel into spatial-spectral joint sparse representation model. With simultaneous subspace pursuit and simultaneous orthogonal matching pursuit to solve the model, the classification is determined by computing the minimum reconstruction error between testing samples and training pixels. Two typical hyperspectral images from AVIRIS and ROSIS are chosen for simulation experiment and results display that the classification accuracy of two images both improves as neighborhood segmentation threshold increasing. It concludes that neighborhood segmentation is necessary for joint sparse representation classification.
入藏号: WOS:000383306800036
ISSN: 1000-0593
第 75 条,共 261 条
标题: Refractometer probe based on a reflective carbon nanotube-modified microfiber Bragg grating
作者: Jiang, BQ (Jiang, Biqiang); Xue, M (Xue, Meng); Zhao, CY (Zhao, Chenyang); Mao, D (Mao, Dong); Zhou, KM (Zhou, Kaiming); Zhang, L (Zhang, Lin); Zhao, JL (Zhao, Jianlin)
来源出版物: APPLIED OPTICS 卷: 55 期: 25 页: 7037-7041 DOI: 10.1364/AO.55.007037 出版年: SEP 2016
摘要: A carbon nanotube (CNT)-modified microfiber Bragg grating (MFBG) is proposed to measure the refractive index with a strong enhancement of the sensitivity in the low refractive index region. The introduction of the CNT layer influences the evanescent field of the MFBG and causes modification of the reflection spectrum. With the increase of the surrounding refractive index (SRI), we observe significant attenuation to the peak of the Bragg resonance, while its wavelength remains almost unchanged. Our detailed experimental results disclose that the CNT-MFBG demonstrates strong sensitivity in the low refractive index range of 1.333-1.435, with peak intensity up to -53.4 dBm/refractive index unit, which is 15-folds higher than that of the uncoated MFBG. Therefore, taking advantage of the CNT-induced evanescent field enhancement, the reflective MFBG probe presents strong sensing capability in biochemical fields. (C) 2016 Optical Society of America
入藏号: WOS:000383994600033
PubMed ID: 27607280
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhou, Kaiming         E-5903-2011         0000-0002-6011-1912
Mao, 8731629         G-5113-2014         0000-0002-5744-6316
ISSN: 1559-128X
eISSN: 2155-3165
第 76 条,共 261 条
标题: A parallel primal-dual splitting method for image restoration
作者: He, C (He, Chuan); Hu, CH (Hu, Changhua); Li, XL (Li, Xuelong); Zhang, W (Zhang, Wei)
来源出版物: INFORMATION SCIENCES 卷: 358 页: 73-91 DOI: 10.1016/j.ins.2016.04.004 出版年: SEP 1 2016
摘要: We develop a parallel primal-dual splitting method to solve large-scale image restoration problems, which involve the sum of several linear-operator-coupled nonsmooth but proximable terms. With the proposed method, the objective function is decomposed into pieces that can be processed individually. No inverse operator is involved in our method and the highly parallel structure makes it preferable in distributed computation. The convergence is proven and the convergence rate is analyzed. Besides, its equivalence to the relaxed parallel linearized alternating direction method of multipliers (PLADMM) is addressed. Applications to image restoration problems with compound l(1)-regularizer and comparisons with state-of-the-art methods are detailed to show the superiority of the proposed method. (C) 2016 Elsevier Inc. All rights reserved.
入藏号: WOS:000377322500006
ISSN: 0020-0255
eISSN: 1872-6291
第 77 条,共 261 条
标题: High-power, high-efficiency 808 nm laser diode array
作者: Wang, ZF (Wang Zhen-Fu); Yang, GW (Yang Guo-Wen); Wu, JY (Wu Jian-Yao); Song, KC (Song Ke-Chang); Li, XS (Li Xiu-Shan); Song, YF (Song Yun-Fei)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 16 文献号: 164203 DOI: 10.7498/aps.65.164203 出版年: AUG 20 2016
摘要: High-power, high-efficiency 808 nm laser diode arrays for pumping solid-state lasers have been widely used in industrial, scientific, medical and biological applications. The tendency of development of 808 nm laser diode pumping with high power, high efficiency and long lifetime is well-known. Diode-pumped solid-state system with high-efficiency laser diode array has many advantages such as compact volume, lower weight and energy saving. Currently, commercial 808 nm diode laser arrays with lower power conversion efficiency of about 50%-55%, due to the optical absorption losses for GaAs-based epitaxial materials, have been reported.
In order to reduce series resistance and thermal resistance, heavily doped p-type waveguide and cladding layers are employed. However, the absorption loss on the free carriers in heavily doped p-type layers is dominant, leading to a lower power conversion efficiency. In order to achieve a high efficiency, the following requirements must be considered: improving the internal quantum efficiency by reducing the carrier leakage and increasing the electron injection efficiency; minimizing the voltage drop by optimizing the operating voltage; reducing the series resistance and thermal resistance of device; minimizing the internal loss including free-carrier absorption loss and scattering loss by designing optimized waveguide and cladding structure.
In this paper, optimizing the epitaxial structure and fabricating technologies are demonstrated to achieve the high efficiency and high power. The asymmetric broad waveguide epitaxial structure with lower absorption loss in p-type waveguide and cladding layer is designed in order to achieve the above goals. The high-efficiency epitaxial structure is optimized including the thickness, doping and composition for each layer structure. The strained quantum well diode laser with lower transparency current and higher differential is of benefit to achieving the high power. A novel asymmetric broad waveguide structure is designed by optimizing the waveguide thickness and component of p-waveguide so as to reduce carrier absorption loss, the optical absorption loss in this epitaxial structure is achieved to be as low as 0.63 cm(-1).
The wafer is grown by metalorganic chemical vapor deposition on an n-GaAs substrate. The optimized growth conditions and substrates orientation are extensively studied to improve the crystal quality and reduce the internal loss and defects. The wafer is processed using standard procedures. For the fabricated 1-cm laser diode array mounted on P-side down on copper microchannel cooled heatsink, the device shows an output power of 150 W under an operating current of 135 A with an emitting wavelength of 809 nm, an operating voltage of 1.76 V, a slope efficiency of as high as 1.25 W/A, and maximum power conversion efficiency of as high as 65.5%, which is the highest level of 808 nm diode laser array with an output power of 150 W.
入藏号: WOS:000384764500012
ISSN: 1000-3290
第 78 条,共 261 条
标题: Optimization of the electron collection efficiency of a large area MCP-PMT for the JUNO experiment
作者: Chen, L (Chen, Lin); Tian, JS (Tian, Jinshou); Liu, CL (Liu, Chunliang); Wang, YF (Wang, Yifang); Zhao, TC (Zhao, Tianchi); Liu, HL (Liu, Hulin); Wei, YL (Wei, Yonglin); Sai, XF (Sai, Xiaofeng); Chen, P (Chen, Ping); Wang, X (Wang, Xing); Lu, Y (Lu, Yu); Hui, DD (Hui, Dandan); Guo, LH (Guo, Lehui); Liu, SL (Liu, Shulin); Qian, S (Qian, Sen); Xia, JK (Xia, Jingkai); Yan, BJ (Yan, Baojun); Zhu, N (Zhu, Na); Sun, JN (Sun, Jianning); Si, SG (Si, Shuguang); Li, D (Li, Dong); Wang, XC (Wang, Xingchao); Huang, GR (Huang, Guorui); Qi, M (Qi, Ming)
来源出版物: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 卷: 827 页: 124-130 DOI: 10.1016/j.nima.2016.04.100 出版年: AUG 11 2016
摘要: A novel large-area (20-inch) photomultiplier tube based on microchannel plate (MCP-PMTs) is proposed for the Jiangmen Underground Neutrino Observatory (JUNO) experiment. Its photoelectron collection efficiency C-e is limited by the MCP open area fraction (A(open)). This efficiency is studied as a function of the angular (theta), energy (E) distributions of electrons in the input charge cloud and the potential difference (U) between the PMT photocathode and the MCP input surface, considering secondary electron emission from the MCP input electrode. In CST Studio Suite, Finite Integral Technique and Monte Carlo method are combined to investigate the dependence of C-e on theta, E and U. Results predict that C-e can exceed A(open), and are applied to optimize the structure and operational parameters of the 20-inch MCP-PMT prototype. C-e of the optimized MCP-PMT is expected to reach 81.2%. Finally, the reduction of the penetration depth of the MCP input electrode layer and the deposition of a high secondary electron yield material on the MCP are proposed to further optimize C-e. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000376888900017
ISSN: 0168-9002
eISSN: 1872-9576
第 79 条,共 261 条
标题: Extracting signal via stochastic resonance in the semiconductor optical amplifier
作者: Zhao, WL (Zhao, Wulong); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu); Han, J (Han, Jing); Sun, H (Sun, Heng)
来源出版物: CHINESE OPTICS LETTERS 卷: 14 期: 8 文献号: 081901 DOI: 10.3788/COL201614.081901 出版年: AUG 10 2016
摘要: The stochastic resonance based on optical bistability in the semiconductor optical amplifier is numerically investigated to extract a weak pulse signal buried in noise. The output property of optical bistability under different system parameters is analyzed, which determines the performance of the stochastic resonance. Through optimizing these parameters, the noise-hidden signal is extracted via stochastic resonance, in which the maximum cross-correlation gain higher than nine is obtained. This provides a novel technology for detecting a weak optical signal in various signal processing fields.
入藏号: WOS:000382513100019
ISSN: 1671-7694
第 80 条,共 261 条
标题: Optical Bloch oscillations and Zener tunneling of Airy beams in ionic-type photonic lattices
作者: Xiao, FJ (Xiao, Fajun); Zhu, WR (Zhu, Weiren); Shang, WY (Shang, Wuyun); Wang, MR (Wang, Meirong); Zhang, P (Zhang, Peng); Liu, S (Liu, Sheng); Premaratne, M (Premaratne, Malin); Zhao, JL (Zhao, Jianlin)
来源出版物: OPTICS EXPRESS 卷: 24 期: 16 页: 18332-18339 DOI: 10.1364/OE.24.018344 出版年: AUG 8 2016
摘要: We report on the existence of optical Bloch oscillations (OBOs) and Zener tunneling (ZT) of Airy beams in ionic-type photonic lattices with a refractive index ramp. Different from their counterparts in uniform lattices, Airy beams undergoing OBOs show an alternatively switched concave and convex trajectory as well as a periodical revival of input beam profiles. Moreover, the ionic-type photonic lattice established in photorefractive crystal exhibits a reconfigurable lattice structure, which provides a flexible way to tune the amplitude and period of the OBOs. Remarkably, it is demonstrated that the band gap of the lattice can be readily controlled by rotating the lattice inducing beam, which forces the ZT rate to follow two significant different decay curves amidst decreasing index gradient. Our results open up new possibilities for all-optical switching, routing and manipulation of Airy beams. (C) 2016 Optical Society of America
入藏号: WOS:000384716000072
PubMed ID: 27505796
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhu, Weiren         E-7749-2011         
Zhu, Weiren                  0000-0002-6568-738X
Premaratne, Malin                  0000-0002-2419-4431
ISSN: 1094-4087
第 81 条,共 261 条
标题: Temporal distortion analysis of the streak tube
作者: Hui, DD (Hui Dan-Dan); Tian, JS (Tian Jin-Shou); Lu, Y (Lu Yu); Wang, JF (Wang Jun-Feng); Wen, WL (Wen Wen-Long); Liang, LL (Liang Ling-Liang); Chen, L (Chen Lin)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 15 文献号: 158502 DOI: 10.7498/aps.65.158502 出版年: AUG 5 2016
摘要: Streak cameras applied to inertial confinement fusion research and flashless imaging lidar require large working areas. However, the larger the working area, the bigger the temporal distortion is. And the temporal distortion has a great influence on the detecting precision of the streak camera, resulting in an image distortion on the screen. Yet previous streak camera design work emphasized shorter time resolution and higher special resolution with paying less attention to the temporal distortion extent. Key factors that may affect the temporal distortion are thoroughly analyzed in this paper. We calculate the electric field of a small-size streak tube with the aid of the Computer Simulation Technology Particle Studio software which is a three-dimensional electromagnetic simulation software based on finite integration technology. Axial electric field distributions at different distances to the axis of the small-size streak tube are displayed. The electron trajectories launched from different points on photocathode of the streak tube are tracked through interpolating pre-calculated electromagnetic field to the particle position. It is known that curved photocathode can reduce the temporal distortion, so we calculate the temporal distortions of streak tubes whose radii of curvature of the photocathode are 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, and 55 mm respectively to ascertain how the curvature influences the temporal distortion. The results show that the temporal distortion is mainly produced in the photocathode-to-deflector region, and it is negligible in the equipotential region. Also, bigger radius of curvature of the photocathode leads to a positive temporal distortion, and smaller one leads to a negative temporal distortion. And the absolute value of the temporal distortion increases with the increase of the slit length. The small-size streak tube whose radius of curvature of the photocathode is 40 mm owns the smallest temporal distortion. We also calculate the temporal distortions of electrons launched from the different positions of the photocathode with different initial energies, and the initial energy has little influence on the temporal distortion. To sum up, the dominating factor that produces the temporal distortion is the curvature of the photocathode. The slit image under a ramp sweeping voltage on screen is curved due to the temporal distortion. And the bigger the temporal distortion, the greater the curvature of the slit image is. Besides, a linear relation between the temporal distortion and deflection of the slit image is displayed. The spatial resolutions of the streak tubes with the radii of curvature of the photocathode 30 mm, 40 mm, 50 mm are calculated respectively. And the small-size streak tube whose radius of curvature of the photocathode is 30 mm has the highest spatial resolution. The radius of curvature of the streak tube photocathode should be carefully selected according to actual requirements for the streak camera. Through the analysis we provide a significant guidance for streak tube design.
入藏号: WOS:000384762400032
ISSN: 1000-3290
第 82 条,共 261 条
标题: Optical design of infrared diffractive telescope
作者: Wang, H (Wang Hao); Kang, FZ (Kang Fu-Zeng); Zhao, W (Zhao Wei); Xie, YJ (Xie Yong-Jun)
来源出版物: JOURNAL OF INFRARED AND MILLIMETER WAVES 卷: 35 期: 4 页: 425-429 DOI: 10.11972/j.issn.1001-9014.2016.04.008 出版年: AUG 2016
摘要: A design example of diffractive telescope is presented and the aperture of objective is 3 meters. The operating wavelength of the system is 7. 7 similar to 10. 3 pm and spectral bandwidth vertical bar Delta lambda/lambda vertical bar is about 1/3. It is shown that the system approximately attains diffraction limit. We developed a small scale diffractive telescope and its' image quality was perfect.
入藏号: WOS:000386195600008
ISSN: 1001-9014
第 83 条,共 261 条
标题: High-peak-power sub-nanosecond intracavity KTiOPO4 optical parametric oscillator pumped by a dual-loss modulated laser with acousto-optic modulator and single-walled carbon nanotube
作者: Qiao, JP (Qiao, Junpeng); Zhao, SZ (Zhao, Shengzhi); Yang, KJ (Yang, Kejian); Zhao, J (Zhao, Jia); Li, GQ (Li, Guiqiu); Li, DC (Li, Dechun); Li, T (Li, Tao); Qiao, WC (Qiao, Wenchao); Lu, JR (Lu, Jianren); Wang, YG (Wang, Yonggang); Chu, HW (Chu, Hongwei); Luan, C (Luan, Chao)
来源出版物: APPLIED PHYSICS EXPRESS 卷: 9 期: 8 文献号: 082701 DOI: 10.7567/APEX.9.082701 出版年: AUG 2016
摘要: A high-peak-power low-repetition-rate sub-nanosecond intracavity KTiOPO4 (KTP) optical parametric oscillator (OPO) pumped by a doubly Q-switched and mode-locked (QML) YVO4/Nd: YVO4 laser with an acousto-optic modulator (AOM) and a single-walled carbon nanotube saturable absorber (SWCNT-SA) has been demonstrated. A maximum output power of 373mW at a signal wavelength of 1570nm was obtained. The smallest pulse width, highest pulse energy, and greatest peak power of mode-locking pulses were estimated to be 119 ps, 124 mu J, and 1.04 MW, respectively, under a maximum incident pump power of 8.3W and an AOM repetition rate of 2 kHz. This OPO operation paves a simple way to produce eye-safe laser sources at 1570nm with low repetition rates, small pulse widths, and high peak powers. (C) 2016 The Japan Society of Applied Physics
入藏号: WOS:000383983200018
ISSN: 1882-0778
eISSN: 1882-0786
第 84 条,共 261 条
标题: Polarization-insensitive tunable multiple electromagnetically induced transparencies analogue in terahertz graphene metamaterial
作者: Chen, X (Chen, Xu); Fan, WH (Fan, Wenhui)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 6 期: 8 页: 2607-2615 DOI: 10.1364/OME.6.002607 出版年: AUG 1 2016
摘要: A graphene-based metamaterial structure composed of multilayer graphene/dielectric stacking configuration is proposed, which achieves multiple analogue of electromagnetically induced transparencies (EIT) effect at terahertz frequencies. Using the phase-coupling scheme, a theoretical model is established to study the EIT-like effect of the proposed structure, and the theoretical calculations coincide well with the numerical simulated results. By varying the Fermi energy level of the graphene, the EIT-like windows can be dynamically tuned in a wide range of terahertz spectra. Particularly, since the symmetry of the structure, the EIT-like effect is polarization-insensitive and can be performed very well in a large incident angles, nearly 80 degrees for both transverse electric and transverse magnetic waves. The proposed structure has potential applications in tunable terahertz chip-integrated optical devices, especially for dynamic multi-band filters, sensors, modulators and nonlinear devices. (C) 2016 Optical Society of America
入藏号: WOS:000382006900016
ISSN: 2159-3930
第 85 条,共 261 条
标题: Effect of the gradient constant temperature on the electrochemical capacitance of cotton stalk-based activated carbon
作者: Li, WL (Li, Wenlong); Wumaier, T (Wumaier, Tuerdi); Chen, MD (Chen, Mingde); Zhang, J (Zhang, Ji); Liu, H (Liu, Huan); Yang, LQ (Yang, LiQing); Wang, HJ (Wang, Haojing)
来源出版物: JOURNAL OF SOLID STATE ELECTROCHEMISTRY 卷: 20 期: 8 页: 2315-2321 DOI: 10.1007/s10008-016-3235-2 出版年: AUG 2016
摘要: The cost-effective activated carbon based from waste cotton stalks by the KOH activation method is investigated as the electrode material in supercapacitor for the first time. Activation temperature control is one of the most important factors affecting the surface area and pore structure of activated carbon, and it influences the capacitive performance of activated carbon based from cotton stalk. The optimized conditions are as follows: cotton stalk base charcoals and activating agent with a mass ration of 1:4, at an activation temperature of 600, 700, and 800A degrees C for 1, 1, and 2 h, respectively. With these experimental conditions, the activated carbon presents excellent electrochemical characteristics. The specific capacitance of the prepared activated carbon was as high as 180 F g(-1)at 2 A g(-1) in 1.0 mol center dot L-1 Et4NBF4/AN electrolyte and the specific capacitance without obvious attenuation after 2000 cycles. So, it is reasonable to believe that the activated carbons from cotton stalks by the KOH gradient constant temperature activation method might be one of the innovative carbon electrode materials for supercapacitor.
入藏号: WOS:000380120600024
ISSN: 1432-8488
eISSN: 1433-0768
第 86 条,共 261 条
标题: Robust Semi-Supervised Subspace Clustering via Non-Negative Low-Rank Representation
作者: Fang, XZ (Fang, Xiaozhao); Xu, Y (Xu, Yong); Li, XL (Li, Xuelong); Lai, ZH (Lai, Zhihui); Wong, WK (Wong, Wai Keung)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 8 页: 1828-1838 DOI: 10.1109/TCYB.2015.2454521 出版年: AUG 2016
摘要: Low-rank representation (LRR) has been successfully applied in exploring the subspace structures of data. However, in previous LRR-based semi-supervised subspace clustering methods, the label information is not used to guide the affinity matrix construction so that the affinity matrix cannot deliver strong discriminant information. Moreover, these methods cannot guarantee an overall optimum since the affinity matrix construction and subspace clustering are often independent steps. In this paper, we propose a robust semi-supervised subspace clustering method based on non-negative LRR (NNLRR) to address these problems. By combining the LRR framework and the Gaussian fields and harmonic functions method in a single optimization problem, the supervision information is explicitly incorporated to guide the affinity matrix construction and the affinity matrix construction and subspace clustering are accomplished in one step to guarantee the overall optimum. The affinity matrix is obtained by seeking a non-negative low-rank matrix that represents each sample as a linear combination of others. We also explicitly impose the sparse constraint on the affinity matrix such that the affinity matrix obtained by NNLRR is non-negative low-rank and sparse. We introduce an efficient linearized alternating direction method with adaptive penalty to solve the corresponding optimization problem. Extensive experimental results demonstrate that NNLRR is effective in semi-supervised subspace clustering and robust to different types of noise than other state-of-the-art methods.
入藏号: WOS:000379984500011
作者识别号:
作者        ResearcherID 号        ORCID 号
Wong, Wai Keung                  0000-0002-5214-7114
ISSN: 2168-2267
eISSN: 2168-2275
第 87 条,共 261 条
标题: Low-Rank Preserving Projections
作者: Lu, YW (Lu, Yuwu); Lai, ZH (Lai, Zhihui); Xu, Y (Xu, Yong); Li, XL (Li, Xuelong); Zhang, D (Zhang, David); Yuan, C (Yuan, Chun)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 8 页: 1900-1913 DOI: 10.1109/TCYB.2015.2457611 出版年: AUG 2016
摘要: As one of the most popular dimensionality reduction techniques, locality preserving projections (LPP) has been widely used in computer vision and pattern recognition. However, in practical applications, data is always corrupted by noises. For the corrupted data, samples from the same class may not be distributed in the nearest area, thus LPP may lose its effectiveness. In this paper, it is assumed that data is grossly corrupted and the noise matrix is sparse. Based on these assumptions, we propose a novel dimensionality reduction method, named low-rank preserving projections (LRPP) for image classification. LRPP learns a low-rank weight matrix by projecting the data on a low-dimensional subspace. We use the L-21 norm as a sparse constraint on the noise matrix and the nuclear norm as a low-rank constraint on the weight matrix. LRPP keeps the global structure of the data during the dimensionality reduction procedure and the learned low rank weight matrix can reduce the disturbance of noises in the data. LRPP can learn a robust subspace from the corrupted data. To verify the performance of LRPP in image dimensionality reduction and classification, we compare LRPP with the state-of-the-art dimensionality reduction methods. The experimental results show the effectiveness and the feasibility of the proposed method with encouraging results.
入藏号: WOS:000379984500017
PubMed ID: 26277014
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhang, David         O-9396-2016         0000-0002-5027-5286
ISSN: 2168-2267
eISSN: 2168-2275
第 88 条,共 261 条
标题: Single-walled carbon nanotube saturable absorber for a diode-pumped passively mode-locked Nd,Y:SrF2 laser
作者: Li, C (Li, Chun); Cai, W (Cai, Wei); Liu, J (Liu, Jie); Su, LB (Su, Liangbi); Jiang, DP (Jiang, Dapeng); Ma, FK (Ma, Fengkai); Zhang, Q (Zhang, Qian); Xu, J (Xu, Jun); Wang, YG (Wang, Yonggang)
来源出版物: OPTICS COMMUNICATIONS 卷: 372 页: 76-79 DOI: 10.1016/j.optcom.2016.04.012 出版年: AUG 1 2016
摘要: A reflective single-walled carbon nanotube as saturable absorber has been firstly adopted to a passively mode-locked Nd,Y:SrF2 crystal. Without any dispersion compensation, the stably mode-locked laser delivers pulses with pulse width as short as 1.7 ps, repetition rate of 107.8 MHz and center wavelength of 1056 nm. The oscillator produces maximum average output power of 319 mW corresponding with a high slope efficiency of 20.2%. The single pulse energy and the peak power are 2.96 nJ and 1.74 kW, respectively. The experimental results show that single-walled carbon nanotube is an excellent saturable absorber for mode-locked lasers. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000375424000011
ISSN: 0030-4018
eISSN: 1873-0310
第 89 条,共 261 条
标题: Congested scene classification via efficient unsupervised feature learning and density estimation
作者: Yuan, Y (Yuan, Yuan); Wan, J (Wan, Jia); Wang, Q (Wang, Qi)
来源出版物: PATTERN RECOGNITION 卷: 56 页: 159-169 DOI: 10.1016/j.patcog.2016.03.020 出版年: AUG 2016
摘要: An unsupervised learning algorithm with density information considered is proposed for congested scene classification. Though many works have been proposed to address general scene classification during the past years, congested scene classification is not adequately studied yet. In this paper, an efficient unsupervised feature learning approach with density information encoded is proposed to solve this problem. Based on spherical k-means, a feature selection process is proposed to eliminate the learned noisy features. Then, local density information which better reflects the crowdedness of a scene is encoded by a novel feature pooling strategy. The proposed method is evaluated on the assembled congested scene data set and UIUC-sports data set, and intensive comparative experiments justify the effectiveness of the proposed approach. (C) 2016 Elsevier Ltd. All rights reserved.
入藏号: WOS:000375360900013
ISSN: 0031-3203
eISSN: 1873-5142
第 90 条,共 261 条
标题: Optimization effect of annealing treatment on oxygen-implanted Nd:CNGG waveguides
作者: Liu, CX (Liu, Chun-Xiao); Fu, LL (Fu, Li-Li); Cheng, LL (Cheng, Liang-Liang); Zhu, XF (Zhu, Xu-Feng); Lin, SB (Lin, She-Bao); Zheng, RL (Zheng, Rui-Lin); Zhou, ZG (Zhou, Zhi-Guang); Guo, HT (Guo, Hai-Tao); Li, WN (Li, Wei-Nan); Wei, W (Wei, Wei)
来源出版物: MODERN PHYSICS LETTERS B 卷: 30 期: 20 文献号: 1650261 DOI: 10.1142/S0217984916502614 出版年: JUL 30 2016
摘要: Neodymium-doped calcium niobium gallium garnet (Nd:CNGG) waveguide operated at 632.8 nm is demonstrated by the 3.0-MeV oxygen-ion implantation with a fluence of 6.0 x 10(14) ions/cm(2). The annealing treatment at 300 degrees C for 45 min is carried out to optimize the waveguide quality. The dark-mode spectra are measured by the m-line technique. The refractive index profiles are calculated from the effective refractive indices of the waveguide modes. The near-field intensity distributions are simulated based on the reconstructed refractive index profiles. The annealing treatment process could effectively remove unwanted defects and optimize the waveguide quality. The optical properties of the annealed waveguide are better than that of the as-implanted waveguide.
入藏号: WOS:000382850000011
ISSN: 0217-9849
eISSN: 1793-6640
第 91 条,共 261 条
标题: MoS2-clad microfibre laser delivering conventional, dispersion-managed and dissipative solitons
作者: Cui, YD (Cui, Yudong); Lu, FF (Lu, Feifei); Liu, XM (Liu, Xueming)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 30524 DOI: 10.1038/srep30524 出版年: JUL 26 2016
摘要: Molybdenum disulfide (MoS2), whose monolayer possesses a direct band gap, displays promising applications in optoelectronics, photonics, and lasers. Recent researches have demonstrated that MoS2 has not only a significant broadband saturable absorption performance, but also a higher optical nonlinear response than graphene. However, MoS2 shows much lower optical damage threshold owing to the poorer thermal conductivity and mechanical property. Here, we exploit a MoS2-clad microfibre (MCM) as the saturable absorber (SA) for the generation of ultrashort pulses under different dispersion conditions. The improved evanescent field interaction scheme can overcome the laser-induced thermal damage, as well as take full advantage of the strong nonlinear effect of MoS2. With the MCM SA, conventional, dispersion-managed, and dissipative solitons are generated around 1600 nm in Er-doped fibre lasers with anomalous, near-zero, and normal cavity dispersions, respectively. Our work paves the way for applications of 2D layered materials in photonics, especially in laser sources.
入藏号: WOS:000384420700001
PubMed ID: 27456468
ISSN: 2045-2322
第 92 条,共 261 条
标题: 34-fs, all-fiber all-polarization-maintaining single-mode pulse nonlinear amplifier
作者: Yu, J (Yu, Jia); Feng, Y (Feng, Ye); Cai, YJ (Cai, Yajun); Li, XH (Li, Xiaohui); Hu, XH (Hu, Xiaohong); Zhang, W (Zhang, Wei); Duan, LN (Duan, Lina); Yang, Z (Yang, Zhi); Wang, YS (Wang, Yishan); Liu, YS (Liu, Yuanshan); Zhao, W (Zhao, Wei)
来源出版物: OPTICS EXPRESS 卷: 24 期: 15 页: 16630-16637 DOI: 10.1364/OE.24.016630 出版年: JUL 25 2016
摘要: We present an all-fiber all-polarization-maintaining (PM) single mode (SM) fiber pulse nonlinear amplification system. The seed laser with a repetition rate of 200 MHz is amplified by two-section erbium-doped PM gain fibers with different peak-absorption rate. The amplified pulse duration can be compressed into 34-fs with 320-mW output power, which corresponds to 1.6-nJ pulse energy and approximate 23.5-kW peak power. In addition, the amplified and compressed pulse is further coupled into the high nonlinear fiber and an octave-spanning supercontinuum generation can be obtained. To the best of our knowledge, it is the highest peak power and the shortest pulse duration obtained in the field of all-fiber all-PM SM pulse-amplification systems. (C) 2016 Optical Society of America
入藏号: WOS:000384715800043
PubMed ID: 27464117
作者识别号:
作者        ResearcherID 号        ORCID 号
Jia, Yu         F-2165-2017         0000-0003-1737-7667
Li, Xiaohui         J-9580-2012         0000-0002-5600-3820
ISSN: 1094-4087
第 93 条,共 261 条
标题: Characteristics of the orbital rotation in dual-beam fiber-optic trap with transverse offset
作者: Chen, XL (Chen, Xinlin); Xiao, GZ (Xiao, Guangzong); Yang, KY (Yang, Kaiyong); Xiong, W (Xiong, Wei); Luo, H (Luo, Hui)
来源出版物: OPTICS EXPRESS 卷: 24 期: 15 页: 16952-16960 DOI: 10.1364/OE.24.016961 出版年: JUL 25 2016
摘要: The orbital rotation is an important type of motion of trapped particles apart from translation and spin rotation. It could be realized by introducing a transverse offset to the dual-beam fiber-optic trap. The characteristics (e.g. rotation perimeter and frequency) of the orbital rotation have been analyzed in this article. We demonstrate the influences of offset distance, beam waist separation distance, light power, and radius of the microsphere by both experimental and numerical work. The experiment results, i.e. orbital rotation perimeter and frequency as functions of these parameters, are consistent with the theoretical model in the present work. The orbital rotation amplitude and frequency could be exactly controlled by varying these parameters. This controllable orbital rotation can be easily applied to the area where microfluidic mixing is required. (C) 2016 Optical Society of America
入藏号: WOS:000384715800073
PubMed ID: 27464147
ISSN: 1094-4087
第 94 条,共 261 条
标题: Spatiotemporal soliton solution to generalized nonlinear Schrodinger equation with a parabolic potential in Kerr media
作者: Kong, YC (Kong, Youchao)
来源出版物: OPTICS COMMUNICATIONS 卷: 371 页: 27-33 DOI: 10.1016/j.optcom.2016.03.004 出版年: JUL 15 2016
摘要: A class of new spatiotemporal solitary solution to nonlinear Schrodinger equation with a parabolic potential is investigated analytically and numerically using the F-expansion method and homogeneous balance principle. The propagation characteristics of soliton wave solutions are analyzed with/without spatial-temporal chirp. It is noteworthy that, by calculating spatial and temporal second-order intensity moment, several novel features of optical beam propagations are obtained, such as stable, oscillating, decaying and blowing up. Additionally, controllability of these solutions with the modulation depth of the parabolic potential is demonstrated. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000375423300005
ISSN: 0030-4018
eISSN: 1873-0310
第 95 条,共 261 条
标题: The R&D of the 20 in. MCP-PMTs for JUNO
作者: Chang, YP (Chang, Yaping); Huang, GR (Huang, Guorui); Heng, YK (Heng, Yuekun); Li, D (Li, Dong); Liu, HL (Liu, Huilin); Liu, SL (Liu, Shulin); Li, WH (Li, Weihua); Ning, Z (Ning, Zhe); Qi, M (Qi, Ming); Qian, S (Qian, Sen); Sun, JN (Sun, Jianning); Si, SG (Si, Shuguang); Tian, JS (Tian, Jinshou); Wang, XC (Wang, Xingchao); Wang, X (Wang, Xing); Wang, YF (Wang, Yifang); Wei, YL (Wei, Yonglin); Wang, WW (Wang, Wenwen); Xia, JK (Xia, Jingkai); Xin, LW (Xin, Liwei); Zhao, TC (Zhao, Tianchi)
团体作者: MCP-PMT Workgrp
来源出版物: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 卷: 824 页: 143-144 DOI: 10.1016/j.nima.2015.10.106 出版年: JUL 11 2016
摘要: A new concept of large area photomultiplier based on MCPs was conceived for JUNO by the scientists in IHEP, and with the collaborative work of the MCP-PMT collaboration in China, 8 in. and 20 in. prototypes were produced. Test results show that this type of MCP-PMT can have good SPE performance as the traditional dynode type PMTs. (C) 2015 Elsevier B.V. All rights reserved.
入藏号: WOS:000375408700050
ISSN: 0168-9002
eISSN: 1872-9576
第 96 条,共 261 条
标题: Joint Content Replication and Request Routing for Social Video Distribution Over Cloud CDN: A Community Clustering Method
作者: Hu, H (Hu, Han); Wen, YG (Wen, Yonggang); Chua, TS (Chua, Tat-Seng); Huang, J (Huang, Jian); Zhu, WW (Zhu, Wenwu); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 卷: 26 期: 7 页: 1320-1333 DOI: 10.1109/TCSVT.2015.2455712 出版年: JUL 2016
摘要: The increasing popularity of online social networks (OSNs) has been transforming the dissemination pattern of social video contents. We can utilize the social information propagation pattern to improve the efficiency of social video distribution. In this paper, motivated by the social community classification, we present a social video replication and user request dispatching mechanism in the cloud content delivery network architecture to reduce the system operational cost, while guaranteeing the averaged service latency. Specifically, we first present a community classification method that clusters social users with social relationships, close geolocations, and similar video watching interests into various communities. Then, we conduct a large-scale measurement on a real OSN system to study the diversities of social video propagation and the effectiveness of our communities on smoothing the diversity. Finally, we propose the community-based video replication and request dispatching strategy and formulate it as a constrained optimization problem. Based on a stochastic optimization framework, we derive an online solution and rigorously prove the optimality. We evaluate our algorithm on a real trace under realistic settings and demonstrate that our algorithm can reduce the monetary cost by 30% against traditional approaches with the same service latency.
入藏号: WOS:000384075100010
作者识别号:
作者        ResearcherID 号        ORCID 号
Wen, Yonggang         B-8848-2011         
ISSN: 1051-8215
eISSN: 1558-2205
第 97 条,共 261 条
标题: DSets-DBSCAN: A Parameter-Free Clustering Algorithm
作者: Hou, J (Hou, Jian); Gao, HJ (Gao, Huijun); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 7 DOI: 10.1109/TIP.2016.2559803 出版年: JUL 2016
摘要: Clustering image pixels is an important image segmentation technique. While a large amount of clustering algorithms have been published and some of them generate impressive clustering results, their performance often depends heavily on user-specified parameters. This may be a problem in the practical tasks of data clustering and image segmentation. In order to remove the dependence of clustering results on user-specified parameters, we investigate the characteristics of existing clustering algorithms and present a parameter-free algorithm based on the DSets (dominant sets) and DBSCAN (Density-Based Spatial Clustering of Applications with Noise) algorithms. First, we apply histogram equalization to the pairwise similarity matrix of input data and make DSets clustering results independent of user-specified parameters. Then, we extend the clusters from DSets with DBSCAN, where the input parameters are determined based on the clusters from DSets automatically. By merging the merits of DSets and DBSCAN, our algorithm is able to generate the clusters of arbitrary shapes without any parameter input. In both the data clustering and image segmentation experiments, our parameter-free algorithm performs better than or comparably with other algorithms with careful parameter tuning.
入藏号: WOS:000384521200001
PubMed ID: 28113183
ISSN: 1057-7149
eISSN: 1941-0042
第 98 条,共 261 条
标题: The influence of thermal and free carrier dispersion effects on all-optical wavelength conversion in a silicon racetrack-shaped microring resonator
作者: Wang, ZL (Wang, Zhaolu); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Huang, N (Huang, Nan); Li, SP (Li, Shaopeng); Han, J (Han, Jing)
来源出版物: LASER PHYSICS 卷: 26 期: 7 文献号: 075403 DOI: 10.1088/1054-660X/26/7/075403 出版年: JUL 2016
摘要: We experimentally demonstrate ultra-low pump power wavelength conversion based on four-wave mixing in a silicon racetrack-shaped microring resonator. When the pump and signal are located at the resonance wavelengths, wavelength conversion with a pump power of only 1 mW can be realized in this microring resonator because of the resonant enhancement of the device. However, saturation of the conversion efficiency occurs because of the shift of the resonance peak, which is caused by the change of the effective refractive index induced by a combination of thermal and free carrier dispersion effects, and it is demonstrated that the thermal effect is the leading-order factor for the change of the refractive index. The maximum conversion efficiency of -21 dB is obtained when the pump power is less than 12 mW. This ultra-low-power on-chip wavelength convertor based on a silicon microring resonator can find important potential applications in highly integrated optical circuits for all-optical signal processing.
入藏号: WOS:000384175900014
ISSN: 1054-660X
eISSN: 1555-6611
第 99 条,共 261 条
标题: Infrared small target and background separation via column-wise weighted robust principal component analysis
作者: Dai, YM (Dai, Yimian); Wu, YQ (Wu, Yiquan); Song, Y (Song, Yu)
来源出版物: INFRARED PHYSICS & TECHNOLOGY 卷: 77 页: 421-430 DOI: 10.1016/j.infrared.2016.06.021 出版年: JUL 2016
摘要: When facing extremely complex infrared background, due to the defect of 11 norm based sparsity measure, the state-of-the-art infrared patch-image (IPI) model would be in a dilemma where either the dim targets are over-shrinked in the separation or the strong cloud edges remains in the target image. In order to suppress the strong edges while preserving the dim targets, a weighted infrared patch image (WIPI) model is proposed, incorporating structural prior information into the process of infrared small target and background separation. Instead of adopting a global weight, we allocate adaptive weight to each column of the target patch-image according to its patch structure. Then the proposed WIPI model is converted to a column-wise weighted robust principal component analysis (CWRPCA) problem. In addition, a target unlikelihood coefficient is designed based on the steering kernel, serving as the adaptive weight for each column. Finally, in order to solve the CWPRCA problem, a solution algorithm is developed based on Alternating Direction Method (ADM). Detailed experiment results demonstrate that the proposed method has a significant improvement over the other nine classical or state-of-the-art methods in terms of subjective visual quality, quantitative evaluation indexes and convergence rate. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000381532900053
ISSN: 1350-4495
eISSN: 1879-0275
第 100 条,共 261 条
标题: Optical properties of K9 glass waveguides fabricated by using carbon-ion implantation
作者: Liu, CX (Liu, Chun-Xiao); Wei, W (Wei, Wei); Fu, LL (Fu, Li-Li); Zhu, XF (Zhu, Xu-Feng); Guo, HT (Guo, Hai-Tao); Li, WN (Li, Wei-Nan); Lin, SB (Lin, She-Bao)
来源出版物: JOURNAL OF THE KOREAN PHYSICAL SOCIETY 卷: 69 期: 2 页: 169-173 DOI: 10.3938/jkps.69.169 出版年: JUL 2016
摘要: K9 glass is a material with promising properties that make it attractive for optical devices. Ion implantation is a powerful technique to form waveguides with controllable depth and refractive index profile. In this work, optical planar waveguide structures were fabricated in K9 glasses by using 6.0-MeV C3+-ion implantation with a fluence of 1.0 x 10(15) ions/cm(2). The effective refractive indices of the guided modes were measured by using a prism-coupling system. The refractive index change in the ion-irradiated region was simulated by using the intensity calculation method. The modal intensity profile of the waveguide was calculated and measured by using the finite difference beam propagation method and the end-face coupling technique, respectively. The transmission spectra before and after the implantation showed that the main absorption band was not influenced by the low fluence dopants. The optical properties of the carbon-implanted K9 glass waveguides show promise for use as integrated photonic devices.
入藏号: WOS:000380262000009
ISSN: 0374-4884
eISSN: 1976-8524
第 101 条,共 261 条
标题: Frequency comb generation in the green using silicon nitride microresonators
作者: Wang, LR (Wang, Leiran); Chang, L (Chang, Lin); Volet, N (Volet, Nicolas); Pfeiffer, MHP (Pfeiffer, Martin H. P.); Zervas, M (Zervas, Michael); Guo, HR (Guo, Hairun); Kippenberg, TJ (Kippenberg, Tobias J.); Bowers, JE (Bowers, John E.)
来源出版物: LASER & PHOTONICS REVIEWS 卷: 10 期: 4 页: 631-638 DOI: 10.1002/lpor.201600006 出版年: JUL 2016
摘要: Optical frequency combs enable precision measurements in fundamental physics and have been applied to a growing number of applications, such as molecular spectroscopy, LIDAR and atmospheric trace-gas sensing. In recent years, the generation of frequency combs has been demonstrated in integrated microresonators. Extending their spectral range to the visible is generally hindered by strong normal material dispersion and scattering losses. In this paper, we report the first realization of a green-light frequency comb in integrated high-Q silicon nitride (SiN) ring microresonators. Third-order optical non-linearities are utilized to convert a near-infrared Kerr frequency comb to a broadband green light comb. The 1-THz frequency spacing infrared comb covers up to 2/3 of an octave, from 144 to 226 THz (or 1327-2082 nm), and the simultaneously generated green-light comb is centered around 570-580 THz (or 517-526 nm), with comb lines emitted down to 517 THz (or 580 nm) and up to 597 THz (or 502 nm). The green comb power is estimated to be as high as -9.1 dBm in the bus waveguide, with an on-chip conversion efficiency of -34 dB. The proposed approach substantiates the feasibility of on-chip optical frequency comb generation expanding to the green spectral region or even shorter wavelengths.
入藏号: WOS:000379958800008
作者识别号:
作者        ResearcherID 号        ORCID 号
Guo, Hairun         J-6259-2012         0000-0002-9913-2817
ISSN: 1863-8880
eISSN: 1863-8899
第 102 条,共 261 条
标题: Research on Broadband Spectral Imaging Spectrometer Based on CDP
作者: Zhang, ZF (Zhang Zhou-feng); Hu, BL (Hu Bing-liang); Yin, QY (Yin Qin-ye); Gao, XH (Gao Xiao-hui)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 36 期: 7 页: 2284-2286 DOI: 10.3964/j.issn.1000-0593(2016)07-2284-03 出版年: JUL 2016
摘要: In order to satisfy the application requirements of real-time spectral imaging for moving targets, we design a static, snapshot imaging spectrometer based on a CDP(crossed dispersion prism). The spectral imaging principle is studied, and an optical system of broadband spectral imaging spectrometer is designed according to this principle. Imaging spectrometer consists of a CDP, an imaging lens and a detector, with +/-2 degrees field of view, spectral coverage from 0.6 to 5.0 mu m, The results show that this instrument has a better ability to detect spectral from 0.6 to 5.0 mu m while the average spectral resolution is 20 nm. The technology for dynamic target real-time spectral imaging provides a new technical way. It has a great potential for detecting, locating and identifying unknown energetic events in real-time.
入藏号: WOS:000379990300053
ISSN: 1000-0593
第 103 条,共 261 条
标题: Lung Nodules Detection in CT Images Using Gestalt-Based Algorithm
作者: Qiu, S (Qiu Shi); Wen, DS (Wen Desheng); Cui, Y (Cui Ying); Feng, J (Feng Jun)
来源出版物: CHINESE JOURNAL OF ELECTRONICS 卷: 25 期: 4 页: 711-718 DOI: 10.1049/cje.2016.07.009 出版年: JUL 2016
摘要: To overcome low accuracy and high false positive of existing computer-aided lung nodules detection. We propose a novel lung nodule detection scheme based on the Gestalt visual cognition theory. The proposed scheme involves two parts which simulate human eyes cognition features such as simplicity, integrity and classification. Firstly, lung region was segmented from lung Computed tomography (CT) sequences. Then local three-dimensional information was integrated into the Maximum intensity projection (MIP) images from axial, coronal and sagittal profiles. In this way, lung nodules and vascular are strengthened and discriminated based on pathologic image characteristics of lung nodules. The experimental database includes fifty-three high resolution CT images contained lung nodules, which had been confirmed by biopsy. The experimental results show that, the accuracy rate of the proposed algorithm achieves 91.29%. The proposed framework improves performance and computation speed for computer aided nodules detection.
入藏号: WOS:000379796700018
ISSN: 1022-4653
eISSN: 2075-5597
第 104 条,共 261 条
标题: Angle Compensation and Asymmetry Effect of Light Diffracted by Millimeter Liquid Surface Slosh Wave
作者: Miao, Y (Miao, Yang); Wu, C (Wu, Can); Wang, N (Wang, Ning); You, JQ (You, Jia-Qi)
来源出版物: CHINESE PHYSICS LETTERS 卷: 33 期: 7 文献号: 074206 DOI: 10.1088/0256-307X/33/7/074206 出版年: JUL 2016
摘要: The angle compensation method is adopted to detect sloshing waves by laser diffraction, in the case that the wavelength of the sloshing waves is much greater than that of the incident light. The clear diffraction pattern is observed to be of asymmetry, involving orders, position and interval of the diffraction spots that are discovered during the light grazing incidence. It is found that the larger the angle of incidence is, the more obvious the asymmetry is. The higher the negative diffraction orders are, the smaller the intervals between spots are. On the contrary, in the positive region, the higher the diffraction orders are, the larger the spot intervals are. The positive interval is larger than that of the same negative diffraction order. If the incident angle reaches 1.558 rad in the experiment, all positive diffraction orders completely vanish. Based on the mechanism of phase modulation and with the Fourier transform method, the relations between the incident angle and position, interval spaces, and orders of diffraction spots are derived theoretically. The theoretical calculations are compared with the experimental data, and the comparison shows that the theoretical calculations are in good agreement with the experimental measurement.
入藏号: WOS:000379260700022
ISSN: 0256-307X
eISSN: 1741-3540
第 105 条,共 261 条
标题: High-Order Energies for Stereo Segmentation
作者: Peng, JT (Peng, Jianteng); Shen, JB (Shen, Jianbing); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 7 页: 1616-1627 DOI: 10.1109/TCYB.2015.2453091 出版年: JUL 2016
摘要: In this paper, we propose a novel segmentation approach for stereo images using the high-order energy optimization, which utilizes the disparity maps and statistical information of stereo images to enrich the high-order potential functions. To the best of our knowledge, our approach is the first one to formulate the problem of stereo segmentation as a high-order energy optimization problem, which simultaneously segments the foreground objects in left and right images using the proposed high-order potential function. A new method for designing the penalty function in our high-order term is proposed by the corresponding pixels and their neighboring pixels between left and right images. The relationships of stereo correspondence by disparity maps are further employed to enhance the connections between the left and right stereo images. Experimental results demonstrate that the proposed approach can effectively improve the performance of two kinds of stereo segmentation, including the automatic saliency-aware stereocut and the interactive stereo segmentation with user scribbles.
入藏号: WOS:000379757900011
ISSN: 2168-2267
eISSN: 2168-2275
第 106 条,共 261 条
标题: Optical waveguides in Er3+/Yb3+-codoped silicate glasses fabricated by proton implantation
作者: Liu, CX (Liu, Chun-Xiao); Fu, LL (Fu, Li-Li); Zhu, XF (Zhu, Xu-Feng); Guo, HT (Guo, Hai-Tao); Li, WN (Li, Wei-Nan); Lin, SB (Lin, She-Bao); Wei, W (Wei, Wei)
来源出版物: JAPANESE JOURNAL OF APPLIED PHYSICS 卷: 55 期: 7 文献号: 072601 DOI: 10.7567/JJAP.55.072601 出版年: JUL 2016
摘要: In this work, a planar waveguide was fabricated by proton implantation in Er3+/Yb3+-codoped silicate glasses with energies of (500 + 550) keV and fluences of (1 + 2) x 10(16) ions/cm(2). The end-face coupling method was employed to determine whether the light could be confined in the waveguide or not. The prism coupling technique was applied to measure the guided mode spectrum and the intensity calculation method was used to construct the refractive index profile. With the profile, a near-field intensity distribution was calculated by the finite difference beam propagation method. The obtained results may be helpful in developing integrated optical devices. (C) 2016 The Japan Society of Applied Physics
入藏号: WOS:000379384600016
ISSN: 0021-4922
eISSN: 1347-4065
第 107 条,共 261 条
标题: Optical trapping force and torque on spheroidal Rayleigh particles with arbitrary spatial orientations
作者: Li, MM (Li, Manman); Yan, SH (Yan, Shaohui); Yao, BL (Yao, Baoli); Liang, YS (Liang, Yansheng); Han, GX (Han, Guoxia); Zhang, P (Zhang, Peng)
来源出版物: JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 卷: 33 期: 7 页: 1341-1347 DOI: 10.1364/JOSAA.33.001341 出版年: JUL 1 2016
摘要: We investigate the spatial orientation dependence of optical trapping forces and intrinsic torques exerted on spheroidal Rayleigh particles under irradiation of highly focused linearly and circularly polarized beams. It is revealed that the maximal trapping forces and torques strongly depend on the orientation of the spheroid, and the spheroidal particle is driven to be stably trapped at the beam focus with its major axis perpendicular to the optical axis. For a linearly polarized trapping beam, the optical torque is always perpendicular to the plane containing the major axis and the polarization direction of the incident beam. Therefore, the spheroid tends to rotate its major axis along with the polarization direction. However, for a circularly polarized trapping beam, the optical torque is always perpendicular to the plane containing the major axis and the optical axis. What is different from the linear polarization case is that the spheroid tends to have the major axis parallel to the projection of the major axis in the transverse plane. The optical torque in the circular polarization case is half of that in the linear polarization case. These optical trapping properties may be exploited in practical optical manipulation, especially for the nonspherical particle's trapping. (C) 2016 Optical Society of America
入藏号: WOS:000379753000021
PubMed ID: 27409691
ISSN: 1084-7529
eISSN: 1520-8532
第 108 条,共 261 条
标题: Spatiotemporal Statistics for Video Quality Assessment
作者: Li, XL (Li, Xuelong); Guo, Q (Guo, Qun); Lu, XQ (Lu, Xiaoqiang)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 7 页: 3329-3342 DOI: 10.1109/TIP.2016.2568752 出版年: JUL 2016
摘要: It is an important task to design models for universal no-reference video quality assessment (NR-VQA) in multiple video processing and computer vision applications. However, most existing NR-VQA metrics are designed for specific distortion types, which are not often aware in practical applications. A further deficiency is that the spatial and temporal information of videos is hardly considered simultaneously. In this paper, we propose a new NR-VQA metric based on the spatiotemporal natural video statistics in 3D discrete cosine transform (3D-DCT) domain. In the proposed method, a set of features are first extracted based on the statistical analysis of 3D-DCT coefficients to characterize the spatiotemporal statistics of videos in different views. These features are used to predict the perceived video quality via the efficient linear support vector regression model afterward. The contributions of this paper are: 1) we explore the spatiotemporal statistics of videos in the 3D-DCT domain that has the inherent spatiotemporal encoding advantage over other widely used 2D transformations; 2) we extract a small set of simple but effective statistical features for video visual quality prediction; and 3) the proposed method is universal for multiple types of distortions and robust to different databases. The proposed method is tested on four widely used video databases. Extensive experimental results demonstrate that the proposed method is competitive with the state-of-art NR-VQA metrics and the top-performing full-reference VQA and reduced-reference VQA metrics.
入藏号: WOS:000377371700004
ISSN: 1057-7149
eISSN: 1941-0042
第 109 条,共 261 条
标题: Optofluidic UV-Vis spectrophotometer for online monitoring of photocatalytic reactions
作者: Wang, N (Wang, Ning); Tan, FR (Tan, Furui); Zhao, Y (Zhao, Yu); Tsoi, CC (Tsoi, Chi Chung); Fan, XD (Fan, Xudong); Yu, WX (Yu, Weixing); Zhang, XM (Zhang, Xuming)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 28928 DOI: 10.1038/srep28928 出版年: JUN 29 2016
摘要: On-chip integration of optical detection units into the microfluidic systems for online monitoring is highly desirable for many applications and is also well in line with the spirit of optofluidics technology-fusion of optics and microfluidics for advanced functionalities. This paper reports the construction of a UV-Vis spectrophotometer on a microreactor, and demonstrates the online monitoring of the photocatalytic degradations of methylene blue and methyl orange under different flow rates and different pH values by detecting the intensity change and/or the peak shift. The integrated device consists of a TiO2-coated glass substrate, a PDMS micro-sized reaction chamber and two flow cells. By comparing with the results of commercial equipment, we have found that the measuring range and the sensitivity are acceptable, especially when the transmittance is in the range of 0.01-0.9. This integrated optofluidic device can significantly cut down the test time and the sample volume, and would provide a versatile platform for real-time characterization of photochemical performance. Moreover, its online monitoring capability may enable to access the usually hidden information in biochemical reactions like intermediate products, time-dependent processes and reaction kinetics.
入藏号: WOS:000378946100001
PubMed ID: 27352840
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhao, Yu         F-5602-2013         0000-0002-6184-2530
Yu, Weixing         G-3658-2012         0000-0002-3216-526X
Zhang, Xuming                  0000-0002-9326-5547
ISSN: 2045-2322
第 110 条,共 261 条
标题: Wireless and sensorless 3D ultrasound imaging
作者: Gao, HT (Gao, Haitao); Huang, QH (Huang, Qinghua); Xu, XM (Xu, Xiangmin); Li, XL (Li, Xuelong)
来源出版物: NEUROCOMPUTING 卷: 195 特刊: SI 页: 159-171 DOI: 10.1016/j.neucom.2015.08.109 出版年: JUN 26 2016
摘要: The past decade has witnessed great advances in three-dimensional (3-D) medical ultrasound (US) imaging instrumentation. An increasing demand for portable 3-D US equipment is one of the main trends upcoming in the market. In this study, we developed a low cost, portable, sensorless and wireless 3-D US imaging system. A laptop US scanner with a conventional linear probe and a convex probe was used to acquire 2-D US B-scans. A client program was developed and run on the US scanner for capturing the pictures of screen during a freehand scanning without a positional sensor, and then the JPEG compression was applied to the pictures for reducing the image data size. The image data was sent to a remote workstation in real-time through Wi-Fi connection. A neural network model was used to recognize the characters (e.g. imaging depth and probe model information) displayed on the screen of the US scanner. The server on the remote workstation communicated with the US scanner, received raw image data, and finally reconstructed 3-D US images. The positions of the B-scans were obtained by estimating the spacings of B-scan image sequence, which was learned by measuring adaptive speckle decorrelation curves in mechanically collected B-scan frames. The performance of the proposed system has been demonstrated through experiments conducted on a US resolution phantom in vitro as well as human tissues in vivo. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000376711800022
ISSN: 0925-2312
eISSN: 1872-8286
第 111 条,共 261 条
标题: Dual-pump Kerr Micro-cavity Optical Frequency Comb with varying FSR spacing
作者: Wang, WQ (Wang, Weiqiang); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Pasquazi, A (Pasquazi, Alessia); Wang, YS (Wang, Yishan); Wang, LR (Wang, Leiran); Zhang, WF (Zhang, Wenfu); Wang, L (Wang, Lei); Hu, XH (Hu, Xiaohong); Wang, GX (Wang, Guoxi); Hu, H (Hu, Hui); Su, YL (Su, Yulong); Li, FT (Li, Feitao); Liu, YS (Liu, Yuanshan); Zhao, W (Zhao, Wei)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 28501 DOI: 10.1038/srep28501 出版年: JUN 24 2016
摘要: In this paper, we demonstrate a novel dual-pump approach to generate robust optical frequency comb with varying free spectral range (FSR) spacing in a CMOS-compatible high-Q micro-ring resonator (MRR). The frequency spacing of the comb can be tuned by an integer number FSR of the MRR freely in our dual-pump scheme. The dual pumps are self-oscillated in the laser cavity loop and their wavelengths can be tuned flexibly by programming the tunable filter embedded in the cavity. By tuning the pump wavelength, broadband OFC with the bandwidth of >180 nm and the frequency-spacing varying from 6 to 46-fold FSRs is realized at a low pump power. This approach could find potential and practical applications in many areas, such as optical metrology, optical communication, and signal processing systems, for its excellent flexibility and robustness.
入藏号: WOS:000378727900001
PubMed ID: 27338250
作者识别号:
作者        ResearcherID 号        ORCID 号
CHU, Sai Tak                  0000-0001-8263-8507
Pasquazi, Alessia                  0000-0003-3330-584X
ISSN: 2045-2322
第 112 条,共 261 条
标题: Incoherent ptychography in Fresnel domain with simultaneous multi-wavelength illumination
作者: Pan, A (Pan An); Wang, D (Wang Dong); Shi, YS (Shi Yi-Shi); Yao, BL (Yao Bao-Li); Ma, Z (Ma Zhen); Han, Y (Han Yang)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 12 文献号: 124201 DOI: 10.7498/aps.65.124201 出版年: JUN 20 2016
摘要: Single wavelength illumination is used in the traditional ptychography. Even though using multi-wavelength to improve image quality, it takes the scheme of illuminating in turn due to the requirement of coherence. So far, the addition of incoherent modes has been regarded as a nuisance in diffractive imaging. Here we propose a scheme of incoherent ptychography and an algorithm of information multiplexing that uses the multi-wavelength illumination simultaneously, which are demonstrated in experiment and simulation. Compared with the scheme of traditional ptychography, it can recover not only the object well, but also the spectral response of the object, probes of complex value and spectral weight of each wavelength respectively. This method obtains much information about the object and owns the multichannel and multispectral merits. Meanwhile, by means of color image coding, this method can retrieve true color images and enhance the image quality. The proposed algorithm has strong robustness. Besides, we also investigate how many modes can be recovered by this method. The work may open up possibilities for information multiplexing in ptychography and multispectral microscopy imaging over various applications.
入藏号: WOS:000380364500010
ISSN: 1000-3290
第 113 条,共 261 条
标题: A parallel alternating direction method with application to compound l(1)-regularized imaging inverse problems
作者: He, C (He, Chuan); Hu, CH (Hu, Changhua); Li, XL (Li, Xuelong); Yang, XG (Yang, Xiaogang); Zhang, W (Zhang, Wei)
来源出版物: INFORMATION SCIENCES 卷: 348 页: 179-197 DOI: 10.1016/j.ins.2016.01.087 出版年: JUN 20 2016
摘要: We derive a parallel alternating direction method of multipliers (PADMM) and apply it to compound l(1)-regularized imaging inverse problems. The proposed method is capable of locating the saddle point of large-scale convex minimization problems with the sum of several nonsmooth but proximable terms. Using an operator splitting strategy, the objective is decomposed into subproblems that are conveniently, individually and simultaneously solved. With the assistance of the Moreau decomposition, our method excludes auxiliary variables that exist in the ADMM and possesses a compacter structure. Thus, the proposed method is preferable in distributed computation. The convergence proof and convergence rate analysis are presented. Application to both image restoration and image compressed sensing demonstrates the effectiveness and efficiency of the proposed method. (C) 2016 Elsevier Inc. All rights reserved.
入藏号: WOS:000373869400012
ISSN: 0020-0255
eISSN: 1872-6291
第 114 条,共 261 条
标题: New Water Vapor Barrier Film Based on Lamellar Aliphatic-Monoamine-Bridged Polysilsesquioxane
作者: Zhang, C (Zhang, Cong); Zhang, C (Zhang, Ce); Ding, RM (Ding, Ruimin); Cui, XM (Cui, Xinmin); Wang, J (Wang, Jing); Zhang, QH (Zhang, Qinghua); Xu, Y (Xu, Yao)
来源出版物: ACS APPLIED MATERIALS & INTERFACES 卷: 8 期: 23 页: 14766-14775 DOI: 10.1021/acsami.6b00878 出版年: JUN 15 2016
摘要: Siloxane-based hybrid lamellar materials with ordered nanostructure units paralleling to the substrate have been widely used for water vapor barrier. However, it is very difficult to control the orientation of the lamellar units at molecular level. In this Research Article, a new lamellar bridged polysilsesquioxane (BPSQ) film, whose voids between lamellae were filled by pendant alkyl chains in the organic bridge, was prepared via the stoichiometric reaction between 3-glycidoxypropyltrimethoxysilane and aliphatic monoamine at 60 degrees C without catalyst. Experimental evidence obtained from FT-IR, MS, NMR, and GIXRD techniques suggested that the as-prepared BPSQ films were constructed by lamellar units with disordered orientation. Nonetheless, they possessed satisfactory water vapor barrier performance for potassium dihydrogen phosphate (KDP) and deuterated potassium dihydrogen phosphate (DKDP) optical crystals, and the water vapor transmission rate through BPSQ film with thickness of 25 mu m was as low as 20.3 g.m(-2) d(-1). Those results proved that filling the voids between molecular lamellae with alkyl chains greatly weakened the effect of lamellar unit orientation on the vapor barrier property of BPSQ film.
入藏号: WOS:000378195000058
PubMed ID: 27224032
ISSN: 1944-8244
第 115 条,共 261 条
标题: Visualization of the 3D structures of small organisms via LED-SIM
作者: Ruan, YY (Ruan, Yongying); Dan, D (Dan, Dan); Zhang, MN (Zhang, Mengna); Bai, M (Bai, Ming); Lei, M (Lei, Ming); Yao, BL (Yao, Baoli); Yang, XK (Yang, Xingke)
来源出版物: FRONTIERS IN ZOOLOGY 卷: 13 文献号: 26 DOI: 10.1186/s12983-016-0158-9 出版年: JUN 14 2016
摘要: Background: Innovative new techniques that aid in the visualization of microscopic anatomical structures have improved our understanding of organismal biology significantly. It is often challenging to observe internal 3D structures, despite the use of techniques such as confocal laser scanning microscopy (CLSM), micro-computed tomography (Micro-CT), magnetic resonance imaging (MRI), focused ion beam scanning electron microscopy (FIB-SEM) and others. In the current paper, we assess LED-SIM (DMD-based LED-illumination structured illumination microscopy), which facilitates the acquisition of nano-and micro-3D structures of small organisms in a high-resolution format (500 nm in the XY-plane and 930 nm along the Z-axis).
Results: We compare other microstructural imaging techniques (involving conventional optical microscopy, CLSM and Micro-CT) with LED-SIM to assess the quality (e.g. resolution, penetration depth, etc.) of LED-SIM images, as well as to document the potential short-comings of LED-SIM. Based on these results we present an optimized set of protocols to ensure that LED-SIM arthropod and nematode samples with different cuticles or textures are prepared for analysis in an optimal manner. Six arthropod and nematode specimens were tested and shown to be suitable for LED-SIM imaging, which was found to yield high resolution 3D images.
Conclusions: Although LED-SIM still must be thoroughly tested before it is widely accepted and the Z-axis resolution still requires improvement, this technique offers distinct high quality 3D images. LED-SIM can be highly effective and may provide high quality 3D images for zoological studies following the guidelines of sample preparation presented in the current paper.
入藏号: WOS:000379681100001
PubMed ID: 27303437
ISSN: 1742-9994
第 116 条,共 261 条
标题: Analysis and calibration of precision for point source transmittance system
作者: Li, ZH (Li Zhao-Hui); Zhao, JK (Zhao Jian-Ke); Xu, L (Xu Liang); Liu, F (Liu Feng); Guo, Y (Guo Yi); Liu, K (Liu Kai); Zhao, Q (Zhao Qing)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 11 文献号: 114206 DOI: 10.7498/aps.65.114206 出版年: JUN 5 2016
摘要: Owing to space optical system working for a long time outside the field of view, where there is strong background radiation, and the fact that the point source transmittance (PST) is an important evaluation indicator for stray light suppression of this optical system, the development of stray light equipment for testing PST has received more and more attention. Though the development of PST testing system has been extensively studied, none of them elaborate on the calibration of the PST testing system. Besides, most of the PST testing systems are at a laboratory research stage, and the calibration of neither testing stability nor accuracy is recognized. Therefore, on the basis of the PST testing system established, one calibration lens is designed to calibrate the PST testing system. By comparing the measured PST values of the calibration lens with the analyzed values, the PST testing system can be evaluated. The calibration lens model is built to analyze PST values at different off-axis angles by using the ray tracing software Tracepro. We consider the accuracy of modeling, and on the basis of simplifying the structure design, we measure bidirectional reflectance distribution function values of the painted surface of the calibration lens, and then estimate values of lens surface from Harvey-Shack model and PSD theory by taking these property data into the model of simulation. Ultimately PST analyzed values of calibration lens can be obtained. Finally, by comparing the measured values of calibration lens, which are tested by using PST testing system, with the analyzed values, the calibration of the PST testing system is completed. In the PST testing process of calibration lens, by analyzing the data at different off-axis angles, the accuracy of repeated measurements and threshold of PST testing system can be obtained. At the same time, testing errors caused by the stability of light source, detector linearity, air scattering and structure of double cylindrical chamber are analyzed through the testing data. The data show that when double cylindrical chamber clean class is ISO 7, the PST threshold of this equipment is 10(8), and the accuracy of repeated measurements is 7.9%. Taking into account the detection capability, the PST threshold of this equipment is 10(-10) when environmental condition is better than ISO 6.
入藏号: WOS:000380364300019
ISSN: 1000-3290
第 117 条,共 261 条
标题: Analysis of the redundancy of Fourier telescopy transmitter array and its redundancy-strehl ratio-target texture distribution characteristic
作者: Zhang, Y (Zhang Yu); Luo, XJ (Luo Xiu-Juan); Cao, B (Cao Bei); Chen, ML (Chen Ming-Lai); Liu, H (Liu Hui); Xia, AL (Xia Ai-Li); Lan, FY (Lan Fu-Yang)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 11 文献号: 114201 DOI: 10.7498/aps.65.114201 出版年: JUN 5 2016
摘要: The Fourier telescopy is a kind of active illumination imaging with high resolution by using multi-interfering fringes generated by the multi-beams from the large transmitter arrays. According to the imaging principle, the beams from one laser source are split and each beam is applied with a different tiny frequency shift so that the interfering fringes may moving across the target. The configuration of the beams changes so that they would generate fringes in different spatial frequencies and different directions. Recently, most of researches focused on the factors such as the baseline scale and data sampling efficiency that may affect the imaging quality. However, there are other two factors, i.e., the configuration of the transmitter and its redundancy, which need studying. In Fourier telescopy, if the direction and spatial frequency of the fringe patterns that are generated by the change of different baseline configurations match each other, the target surface information would be a crucial factor that affects the image quality.
In the first part of this article, the practicability of zero redundancy of baseline is analyzed. The results show that the baseline cannot have zero redundancy due to the iteration algorithm. Then the minimum redundancy is analyzed and the minimum redundancy line is proposed. By using the Strehl ratio as the merit of the imaging quality, the concept of redundancy-strehl ratio-target texture distribution (RST) and calculation method are proposed. This method integrates the transmitter redundancy, target detail information and image quality together. The distribution of RST value on the frequency plane is compared with the minimum redundancy line. If the RST point is located on the horizontal side compared with the line, the target detail information on this baseline is mainly in the horizontal direction. On the other hand, if the RST point is located on the longitude side, the target information is mainly in the longitude direction. Therefore this new proposed method reveals the relationship between target spatial information and the baseline configuration. In this article T-shaped transmitter array is adopted, and the Fourier components are mainly distributed on the rectangle plane. According to this relationship and calculated RST value, the working transmitter may continuously rectify its scale and shifting patterns so that the spatial frequencies and directions of fringes may match the target Fourier components in time. In this article, three simulated images and two real images are tested by the proposed method, and the results show that the RST values and the distributions well reveale the relationship between the detailed information and the baseline configurations.
Now the Fourier telescopy follows the procedure from laboratory setup to the real system research. Considering the convenience and cost of project realization, this method is helpful for analyzing the real system of the transmitter configuration and enhancing working efficiency.
入藏号: WOS:000380364300014
ISSN: 1000-3290
第 118 条,共 261 条
标题: Wideband slow-light propagation with no distortion in a nanofiber-plane-grating composite waveguide
作者: Ma, CJ (Ma, Chengju); Ren, LY (Ren, Liyong); Guo, WG (Guo, Wenge); Fu, HW (Fu, Haiwei); Xu, YP (Xu, Yiping); Liu, YG (Liu, Yinggang); Zhang, XZ (Zhang, Xiaozhen)
来源出版物: OPTICAL ENGINEERING 卷: 55 期: 6 文献号: 066120 DOI: 10.1117/1.OE.55.6.066120 出版年: JUN 2016
摘要: A nanofiber-plane-grating composite slow-light waveguide to achieve wideband slowlight propagation with no distortion is proposed. The waveguide is formed by embedding a tapered nanofiber into a V-groove on a plane-grating surface. By optimizing the waveguide structural parameters, a slow-light effect with bandwidth of about 1453 GHz is obtained. Based on finite-difference time-domain (FDTD) method, we analyze the waveguide's optical properties and slow-light characteristics. Simulation results show that a picosecond optical pulse propagating in the slow-light waveguide can be delayed for about 980 fs and without distortion. The group velocity of the optical pulse can be reduced to about 0.3c (c is the speed of light in vacuum). This study will provide important theoretical basis and innovative ideas for the development of new-type slow-light elements. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000383253900046
作者识别号:
作者        ResearcherID 号        ORCID 号
Ren, Liyong         F-5518-2014         0000-0002-7547-7511
ISSN: 0091-3286
eISSN: 1560-2303
第 119 条,共 261 条
标题: Atom Decomposition with Adaptive Basis Selection Strategy for Matrix Completion
作者: Hu, Y (Hu, Yao); Zhao, C (Zhao, Chen); Cai, D (Cai, Deng); He, XF (He, Xiaofei); Li, XL (Li, Xuelong)
来源出版物: ACM TRANSACTIONS ON MULTIMEDIA COMPUTING COMMUNICATIONS AND APPLICATIONS 卷: 12 期: 3 文献号: 43 DOI: 10.1145/2903716 出版年: JUN 2016
摘要: Estimating missing entries in matrices has attracted much attention due to its wide range of applications like image inpainting and video denoising, which are usually considered as low-rank matrix completion problems theoretically. It is common to consider nuclear norm as a surrogate of the rank operator since it is the tightest convex lower bound of the rank operator under certain conditions. However, most approaches based on nuclear norm minimization involve a number of singular value decomposition (SVD) operations. Given a matrix X is an element of R-mxn, the time complexity of the SVD operation is O(mn(2)), which brings prohibitive computational burden on large-scale matrices, limiting the further usage of these methods in real applications. Motivated by this observation, a series of atom-decomposition-based matrix completion methods have been studied. The key to these methods is to reconstruct the target matrix by pursuit methods in a greedy way, which only involves the computation of the top SVD and has great advantages in efficiency compared with the SVD-based matrix completion methods. However, due to gradually serious accumulation errors, atom-decomposition-based methods usually result in unsatisfactory reconstruction accuracy. In this article, we propose a new efficient and scalable atom decomposition algorithm for matrix completion called Adaptive Basis Selection Strategy (ABSS). Different from traditional greedy atom decomposition methods, a two-phase strategy is conducted to generate the basis separately via different strategies according to their different nature. At first, we globally prune the basis space to eliminate the unimportant basis as much as possible and locate the probable subspace containing the most informative basis. Then, another group of basis spaces are learned to improve the recovery accuracy based on local information. In this way, our proposed algorithm breaks through the accuracy bottleneck of traditional atom-decomposition-based matrix completion methods; meanwhile, it reserves the innate efficiency advantages over SVD-based matrix completion methods. We empirically evaluate the proposed algorithm ABSS on real visual image data and large-scale recommendation datasets. Results have shown that ABSS has much better reconstruction accuracy with comparable cost to atom-decomposition-based methods. At the same time, it outperforms the state-of-the-art SVD-based matrix completion algorithms by similar or better reconstruction accuracy with enormous advantages on efficiency.
入藏号: WOS:000379425400009
ISSN: 1551-6857
eISSN: 1551-6865
第 120 条,共 261 条
标题: Semantic Photo Retargeting Under Noisy Image Labels
作者: Zhang, LM (Zhang, Luming); Li, XL (Li, Xuelong); Nie, LQ (Nie, Liqiang); Yan, Y (Yan, Yan); Zimmermann, R (Zimmermann, Roger)
来源出版物: ACM TRANSACTIONS ON MULTIMEDIA COMPUTING COMMUNICATIONS AND APPLICATIONS 卷: 12 期: 3 文献号: 37 DOI: 10.1145/2886775 出版年: JUN 2016
摘要: With the popularity of mobile devices, photo retargeting has become a useful technique that adapts a high-resolution photo onto a low-resolution screen. Conventional approaches are limited in two aspects. The first factor is the de-emphasized role of semantic content that is many times more important than low-level features in photo aesthetics. Second is the importance of image spatial modeling: toward a semantically reasonable retargeted photo, the spatial distribution of objects within an image should be accurately learned. To solve these two problems, we propose a new semantically aware photo retargeting that shrinks a photo according to region semantics. The key technique is a mechanism transferring semantics of noisy image labels (inaccurate labels predicted by a learner like an SVM) into different image regions. In particular, we first project the local aesthetic features (graphlets in this work) onto a semantic space, wherein image labels are selectively encoded according to their noise level. Then, a category-sharing model is proposed to robustly discover the semantics of each image region. The model is motivated by the observation that the semantic distribution of graphlets from images tagged by a common label remains stable in the presence of noisy labels. Thereafter, a spatial pyramid is constructed to hierarchically encode the spatial layout of graphlet semantics. Based on this, a probabilistic model is proposed to enforce the spatial layout of a retargeted photo to be maximally similar to those from the training photos. Experimental results show that (1) noisy image labels predicted by different learners can improve the retargeting performance, according to both qualitative and quantitative analysis, and (2) the category-sharing model stays stable even when 32.36% of image labels are incorrectly predicted.
入藏号: WOS:000379425400003
作者识别号:
作者        ResearcherID 号        ORCID 号
Zimmermann, Roger                  0000-0002-7410-2590
ISSN: 1551-6857
eISSN: 1551-6865
第 121 条,共 261 条
标题: High-speed, high-voltage pulse generation using avalanche transistor
作者: Gou, YS (Gou Yong-sheng); Liu, BY (Liu Bai-yu); Bai, YL (Bai Yong-lin); Qin, JJ (Qin Jun-jun); Bai, XH (Bai Xiao-hong); Wang, B (Wang Bo); Zhu, BL (Zhu Bing-li); Sun, CD (Sun Chuan-dong)
来源出版物: REVIEW OF SCIENTIFIC INSTRUMENTS 卷: 87 期: 5 文献号: 054708 DOI: 10.1063/1.4948727 出版年: JUN 2016
摘要: In this work, the conduction mechanism of avalanche transistors was demonstrated and the operation condition for generating high-speed pulse using avalanche transistors was illustrated. Based on the above analysis, a high-speed and high-voltage pulse (HHP) generating circuit using avalanche transistors was designed, and its working principle and process were studied. To improve the speed of the output pulse, an approach of reducing the rise time of the leading edge is proposed. Methods for selecting avalanche transistor and reducing the parasitic inductance and capacitance of printed circuit board (PCB) were demonstrated. With these instructions, a PCB with a tapered transmission line was carefully designed and manufactured. Output pulse with amplitude of 2 kV and rise time of about 200 ps was realized with this PCB mounted with avalanche transistors FMMT417, indicating the effectiveness of the HHP generating circuit design. Published by AIP Publishing.
入藏号: WOS:000379187600087
ISSN: 0034-6748
eISSN: 1089-7623
第 122 条,共 261 条
标题: Multifrequency sources of quantum correlated photon pairs on-chip: a path toward integrated Quantum Frequency Combs
作者: Caspani, L (Caspani, Lucia); Reimer, C (Reimer, Christian); Kues, M (Kues, Michael); Roztocki, P (Roztocki, Piotr); Clerici, M (Clerici, Matteo); Wetzel, B (Wetzel, Benjamin); Jestin, Y (Jestin, Yoann); Ferrera, M (Ferrera, Marcello); Peccianti, M (Peccianti, Marco); Pasquazi, A (Pasquazi, Alessia); Razzari, L (Razzari, Luca); Little, BE (Little, Brent E.); Chu, ST (Chu, Sai T.); Moss, DJ (Moss, David J.); Morandotti, R (Morandotti, Roberto)
来源出版物: NANOPHOTONICS 卷: 5 期: 2 特刊: SI 页: 351-362 DOI: 10.1515/nanoph-2016-0029 出版年: JUN 2016
摘要: Recent developments in quantum photonics have initiated the process of bringing photonic-quantum-based systems out-of-the-lab and into real-world applications. As an example, devices to enable the exchange of a cryptographic key secured by the laws of quantum mechanics are already commercially available. In order to further boost this process, the next step is to transfer the results achieved by means of bulky and expensive setups into miniaturized and affordable devices. Integrated quantum photonics is exactly addressing this issue. In this paper, we briefly review the most recent advancements in the generation of quantum states of light on-chip. In particular, we focus on optical microcavities, as they can offer a solution to the problem of low efficiency that is characteristic of the materials typically used in integrated platforms. In addition, we show that specifically designed microcavities can also offer further advantages, such as compatibility with telecom standards (for exploiting existing fibre networks) and quantum memories (necessary to extend the communication distance), as well as giving a longitudinal multimode character for larger information transfer and processing. This last property (i.e., the increased dimensionality of the photon quantum state) is achieved through the ability to generate multiple photon pairs on a frequency comb, corresponding to the microcavity resonances. Further achievements include the possibility of fully exploiting the polarization degree of freedom, even for integrated devices. These results pave the way for the generation of integrated quantum frequency combs that, in turn, may find important applications toward the realization of a compact quantum-computing platform.
入藏号: WOS:000378602900010
作者识别号:
作者        ResearcherID 号        ORCID 号
Clerici, Matteo         F-6416-2010         0000-0002-9100-8539
Peccianti, Marco         F-7127-2011         0000-0001-8894-496X
Ferrera, Marcello                  0000-0003-4479-5127
Pasquazi, Alessia                  0000-0003-3330-584X
CHU, Sai Tak                  0000-0001-8263-8507
moss, david                  0000-0001-5195-1744
Caspani, Lucia                  0000-0003-2711-0448
ISSN: 2192-8606
eISSN: 2192-8614
第 123 条,共 261 条
标题: Highly efficient spectrally encoded imaging using a 45 degrees tilted fiber grating
作者: Wang, GQ (Wang, Guoqing); Wang, C (Wang, Chao); Yan, ZJ (Yan, Zhijun); Zhang, L (Zhang, Lin)
来源出版物: OPTICS LETTERS 卷: 41 期: 11 页: 2398-2401 DOI: 10.1364/OL.41.002398 出版年: JUN 1 2016
摘要: A novel highly efficient, fiber-compatible spectrally encoded imaging (SEI) system using a 45 degrees tilted fiber grating (TFG) is proposed and experimentally demonstrated for the first time, to the best of our knowledge. The TFG serves as an in-fiber lateral diffraction element, eliminating the need for bulky and lossy free-space diffraction gratings in conventional SEI systems. Under proper polarization control, due to the strong tilted reflection, the 45 degrees TFG offers a diffraction efficiency as high as 93.5%. Our new design significantly reduces the volume of the SEI system and improves energy efficiency and system stability. As a proof-of-principle experiment, spectrally encoded imaging of a customer-designed sample (9.6 mm x 3.0 mm) using the TFG-based system is demonstrated. The lateral resolution of the SEI system is measured to be 42 mu m in our experiment. (C) 2016 Optical Society of America
入藏号: WOS:000377466000002
PubMed ID: 27244373
作者识别号:
作者        ResearcherID 号        ORCID 号
Wang, Chao         F-9805-2010         0000-0002-0454-8079
ISSN: 0146-9592
eISSN: 1539-4794
第 124 条,共 261 条
标题: DISC: Deep Image Saliency Computing via Progressive Representation Learning
作者: Chen, TS (Chen, Tianshui); Lin, L (Lin, Liang); Liu, LB (Liu, Lingbo); Luo, XN (Luo, Xiaonan); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 27 期: 6 页: 1135-1149 DOI: 10.1109/TNNLS.2015.2506664 出版年: JUN 2016
摘要: Salient object detection increasingly receives attention as an important component or step in several pattern recognition and image processing tasks. Although a variety of powerful saliency models have been intensively proposed, they usually involve heavy feature (or model) engineering based on priors (or assumptions) about the properties of objects and backgrounds. Inspired by the effectiveness of recently developed feature learning, we provide a novel deep image saliency computing (DISC) framework for fine-grained image saliency computing. In particular, we model the image saliency from both the coarse- and fine-level observations, and utilize the deep convolutional neural network (CNN) to learn the saliency representation in a progressive manner. In particular, our saliency model is built upon two stacked CNNs. The first CNN generates a coarse-level saliency map by taking the overall image as the input, roughly identifying saliency regions in the global context. Furthermore, we integrate superpixel-based local context information in the first CNN to refine the coarse-level saliency map. Guided by the coarse saliency map, the second CNN focuses on the local context to produce fine-grained and accurate saliency map while preserving object details. For a testing image, the two CNNs collaboratively conduct the saliency computing in one shot. Our DISC framework is capable of uniformly highlighting the objects of interest from complex background while preserving well object details. Extensive experiments on several standard benchmarks suggest that DISC outperforms other state-of-the-art methods and it also generalizes well across data sets without additional training. The executable version of DISC is available online: http://vision.sysu.edu.cn/projects/DISC.
入藏号: WOS:000377113300003
PubMed ID: 26742147
ISSN: 2162-237X
eISSN: 2162-2388
第 125 条,共 261 条
标题: Spatiochromatic Context Modeling for Color Saliency Analysis
作者: Zhang, J (Zhang, Jun); Wang, M (Wang, Meng); Zhang, SP (Zhang, Shengping); Li, XL (Li, Xuelong); Wu, XD (Wu, Xindong)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 27 期: 6 页: 1177-1189 DOI: 10.1109/TNNLS.2015.2464316 出版年: JUN 2016
摘要: Visual saliency is one of the most noteworthy perceptual abilities of human vision. Recent progress in cognitive psychology suggests that: 1) visual saliency analysis is mainly completed by the bottom-up mechanism consisting of feedforward low-level processing in primary visual cortex (area V1) and 2) color interacts with spatial cues and is influenced by the neighborhood context, and thus it plays an important role in a visual saliency analysis. From a computational perspective, the most existing saliency modeling approaches exploit multiple independent visual cues, irrespective of their interactions (or are not computed explicitly), and ignore contextual influences induced by neighboring colors. In addition, the use of color is often underestimated in the visual saliency analysis. In this paper, we propose a simple yet effective color saliency model that considers color as the only visual cue and mimics the color processing in V1. Our approach uses region-/boundary-defined color features with spatiochromatic filtering by considering local color-orientation interactions, therefore captures homogeneous color elements, subtle textures within the object and the overall salient object from the color image. To account for color contextual influences, we present a divisive normalization method for chromatic stimuli through the pooling of contrary/complementary color units. We further define a color perceptual metric over the entire scene to produce saliency maps for color regions and color boundaries individually. These maps are finally globally integrated into a one single saliency map. The final saliency map is produced by Gaussian blurring for robustness. We evaluate the proposed method on both synthetic stimuli and several benchmark saliency data sets from the visual saliency analysis to salient object detection. The experimental results demonstrate that the use of color as a unique visual cue achieves competitive results on par with or better than 12 state-of-the-art approaches.
入藏号: WOS:000377113300006
PubMed ID: 26316225
ISSN: 2162-237X
eISSN: 2162-2388
第 126 条,共 261 条
标题: Salient Band Selection for Hyperspectral Image Classification via Manifold Ranking
作者: Wang, Q (Wang, Qi); Lin, JZ (Lin, Jianzhe); Yuan, Y (Yuan, Yuan)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 27 期: 6 页: 1279-1289 DOI: 10.1109/TNNLS.2015.2477537 出版年: JUN 2016
摘要: Saliency detection has been a hot topic in recent years, and many efforts have been devoted in this area. Unfortunately, the results of saliency detection can hardly be utilized in general applications. The primary reason, we think, is unspecific definition of salient objects, which makes that the previously published methods cannot extend to practical applications. To solve this problem, we claim that saliency should be defined in a context and the salient band selection in hyperspectral image (HSI) is introduced as an example. Unfortunately, the traditional salient band selection methods suffer from the problem of inappropriate measurement of band difference. To tackle this problem, we propose to eliminate the drawbacks of traditional salient band selection methods by manifold ranking. It puts the band vectors in the more accurate manifold space and treats the saliency problem from a novel ranking perspective, which is considered to be the main contributions of this paper. To justify the effectiveness of the proposed method, experiments are conducted on three HSIs, and our method is compared with the six existing competitors. Results show that the proposed method is very effective and can achieve the best performance among the competitors.
入藏号: WOS:000377113300014
PubMed ID: 27008675
作者识别号:
作者        ResearcherID 号        ORCID 号
Wang, Qi                  0000-0002-7028-4956
ISSN: 2162-237X
eISSN: 2162-2388
第 127 条,共 261 条
标题: Special Section on Learning in Non-(geo) metric Spaces
作者: Pelillo, M (Pelillo, Marcello); Hancock, ER (Hancock, Edwin R.); Li, XL (Li, Xuelong); Murino, V (Murino, Vittorio)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 27 期: 6 页: 1290-1293 DOI: 10.1109/TNNLS.2016.2522770 出版年: JUN 2016
入藏号: WOS:000377113300015
作者识别号:
作者        ResearcherID 号        ORCID 号
Hancock, Edwin         C-6071-2008         0000-0003-4496-2028
ISSN: 2162-237X
eISSN: 2162-2388
第 128 条,共 261 条
标题: Ensemble Manifold Rank Preserving for Acceleration-Based Human Activity Recognition
作者: Tao, DP (Tao, Dapeng); Jin, LW (Jin, Lianwen); Yuan, Y (Yuan, Yuan); Xue, Y (Xue, Yang)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 27 期: 6 页: 1392-1404 DOI: 10.1109/TNNLS.2014.2357794 出版年: JUN 2016
摘要: With the rapid development of mobile devices and pervasive computing technologies, acceleration-based human activity recognition, a difficult yet essential problem in mobile apps, has received intensive attention recently. Different acceleration signals for representing different activities or even a same activity have different attributes, which causes troubles in normalizing the signals. We thus cannot directly compare these signals with each other, because they are embedded in a nonmetric space. Therefore, we present a nonmetric scheme that retains discriminative and robust frequency domain information by developing a novel ensemble manifold rank preserving (EMRP) algorithm. EMRP simultaneously considers three aspects: 1) it encodes the local geometry using the ranking order information of intraclass samples distributed on local patches; 2) it keeps the discriminative information by maximizing the margin between samples of different classes; and 3) it finds the optimal linear combination of the alignment matrices to approximate the intrinsic manifold lied in the data. Experiments are conducted on the South China University of Technology naturalistic 3-D acceleration-based activity dataset and the naturalistic mobile-devices based human activity dataset to demonstrate the robustness and effectiveness of the new nonmetric scheme for acceleration-based human activity recognition.
入藏号: WOS:000377113300024
PubMed ID: 25265635
ISSN: 2162-237X
eISSN: 2162-2388
第 129 条,共 261 条
标题: Effect of energy density and feeding speed on micro-holes drilling in SiC/SiC composites by picosecond laser
作者: Liu, YS (Liu, Yongsheng); Wang, J (Wang, Jing); Li, WN (Li, Weinan); Wang, CH (Wang, Chunhui); Zhang, Q (Zhang, Qing); Yang, XJ (Yang, Xiaojun); Cheng, LF (Cheng, Laifei)
来源出版物: INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY 卷: 84 期: 9-12 页: 1917-1925 DOI: 10.1007/s00170-015-7844-1 出版年: JUN 2016
摘要: Picosecond laser machining is an important modern technology for materials with high hardness. In this paper, micro-holes with several hundred micrometer diameter were drilled in SiC/SiC composite using picosecond laser, and the quality of the micro-holes under different machining parameters was investigated in detail. The results indicated that energy density and feeding speed had remarkable effect on the micro-hole quality. The roundness of the micro-holes on the laser entry side was rarely affected by energy density and feeding speed. However, the roundness of the micro-holes on the laser exit side and micro-hole diameters along processing direction were quite sensitive to the energy density and feeding speed. Feeding speed had little influence on the quality of drilling holes, except for more debris on the entry side with 11.2 mu m/s feeding speed.
入藏号: WOS:000376462600013
ISSN: 0268-3768
eISSN: 1433-3015
第 130 条,共 261 条
标题: Incrementally Detecting Moving Objects in Video with Sparsity and Connectivity
作者: Pan, J (Pan, Jing); Li, XL (Li, Xiaoli); Li, XL (Li, Xuelong); Pang, YW (Pang, Yanwei)
来源出版物: COGNITIVE COMPUTATION 卷: 8 期: 3 页: 420-428 DOI: 10.1007/s12559-015-9373-5 出版年: JUN 2016
摘要: Moving object detection is crucial for cognitive vision-based robot tasks. However, due to noise, dynamic background, variations in illumination, and high frame rate, it is a challenging task to robustly and efficiently detect moving objects in video using the clue of motion. State-of-the-art batch-based methods view a sequence of images as a whole and then model the background and foreground together with the constraints of foreground sparsity and connectivity (smoothness) in a unified framework. But the efficiency of the batch-based methods is very low. State-of-the-art incremental methods model the background by a subspace whose bases are updated frame by frame. However, such incremental methods do not make full use of the foreground sparsity and connectivity. In this paper, we develop an incremental method for detecting moving objects in video. Compared to existing methods, the proposed method not only incrementally models the subspace for background reconstruction but also takes into account the sparsity and connectivity of the foreground. The optimization of the model is very efficient. Experimental results on nine public videos demonstrate that the proposed method is much efficient than the state-of-the-art batch methods and has higher F1-score than the state-of-the-art incremental methods.
入藏号: WOS:000376284900003
ISSN: 1866-9956
eISSN: 1866-9964
第 131 条,共 261 条
标题: Material research on the InGaAs-emitting-layer VECSEL grown on GaAs substrate (vol 42, pg 283, 2016)
作者: Lin, T (Lin, Tao); Sun, RJ (Sun, Ruijuan); Sun, H (Sun, Hang); Guo, EM (Guo, Enmin); Duan, YP (Duan, Yupeng); Lin, N (Lin, Nan); Ma, XY (Ma, Xiaoyu); Wang, YG (Wang, Yonggang)
来源出版物: MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING 卷: 47 页: 86-86 DOI: 10.1016/j.mssp.2016.03.030 出版年: JUN 1 2016
入藏号: WOS:000375042200014
ISSN: 1369-8001
eISSN: 1873-4081
第 132 条,共 261 条
标题: Optical waveform monitoring based on a free-running mode-locked femtosecond fibre laser and four-wave mixing in a highly nonlinear fibre
作者: Liu, Y (Liu, Y.); Zhang, JG (Zhang, J. -G.); Tang, D (Tang, D.)
来源出版物: OPTO-ELECTRONICS REVIEW 卷: 24 期: 2 页: 62-74 DOI: 10.1515/oere-2016-0010 出版年: JUN 2016
摘要: Optical sampling based on ultrafast optical nonlinearities is a useful technique to monitor the waveforms of ultrashort optical pulses. In this paper, we present a new implementation of optical waveform sampling systems by employing our newly constructed free-running mode-locked fibre laser with a tunable repetition rate and a low timing jitter, an all-optical waveform sampler with a highly nonlinear fibre (HNLF), and our developed computer algorithm for optical waveform display and measurement, respectively. Using a femtosecond fibre laser to generate the highly stable optical sampling pulses and exploiting the four-wave mixing effect in a 100m-long HNLF, we successfully demonstrate the all-optical waveform sampling of a 10GHz optical clock pulse sequence with a pulse width of 1.8 ps and a 80Gbit/s optical data signal, respectively. The experimental results show that waveforms of the tested optical pulse signals are accurately reproduced with a pulse width of 2.0 ps. This corresponds to a temporal resolution of 0.87 ps for optical waveform measurement. Moreover, the optical eye diagram of a 10Gbit/s optical data signal with a 1.8 ps pulse width is also accurately measured by employing our developed optical sampling system.
入藏号: WOS:000375182400003
ISSN: 1230-3402
eISSN: 1896-3757
第 133 条,共 261 条
标题: [INVITED] Ultrafast laser photoinscription of large-mode-area waveguiding structures in bulk dielectrics
作者: Stoian, R (Stoian, R.); D'Amico, C (D'Amico, C.); Bhuyan, MK (Bhuyan, M. K.); Cheng, G (Cheng, G.)
来源出版物: OPTICS AND LASER TECHNOLOGY 卷: 80 页: 98-103 DOI: 10.1016/j.optlastec.2015.11.025 出版年: JUN 2016
摘要: Ultrafast laser photoinscription and laser-based refractive index engineering develop towards a unique way for three-dimensional optical design inside bulk materials for the conception of embedded photonic applications. The specific optical functions for the light guiding elements, notably their single mode characteristics and the accessible spectral domains, depend on the achieved refractive index contrast in the material transparency window and on the characteristic dimensions of the optical modification. We give here an overview of several laser processing options, developed to increase the effective index area and contrast using pulse engineering methods in space and time, and optical design involving focal shaping, tubular concepts, evanescently coupled waveguide arrays, or structured waveguides. (C) 2015 Elsevier Ltd. All rights reserved.
入藏号: WOS:000371102200014
ISSN: 0030-3992
eISSN: 1879-2545
第 134 条,共 261 条
标题: Scattering effects and high-spatial-frequency nanostructures on ultrafast laser irradiated surfaces of zirconium metallic alloys with nano-scaled topographies
作者: Li, C (Li, Chen); Cheng, GH (Cheng, Guanghua); Sedao, X (Sedao, Xxx); Zhang, W (Zhang, Wei); Zhang, H (Zhang, Hao); Faure, N (Faure, Nicolas); Jamon, D (Jamon, Damien); Colombier, JP (Colombier, Jean-Philippe); Stoian, R (Stoian, Razvan)
来源出版物: OPTICS EXPRESS 卷: 24 期: 11 页: 1558-1568 DOI: 10.1364/OE.24.011558 出版年: MAY 30 2016
摘要: The origin of high-spatial-frequency laser-induced periodic surface structures (HSFL) driven by incident ultrafast laser fields, with their ability to achieve structure resolutions below lambda/2, is often obscured by the overlap with regular ripples patterns at quasi-wavelength periodicities. We experimentally demonstrate here employing defined surface topographies that these structures are intrinsically related to surface roughness in the nano-scale domain. Using Zr-based bulk metallic glass (Zr-BMG) and its crystalline alloy (Zr-CA) counterpart formed by thermal annealing from its glassy precursor, we prepared surfaces showing either smooth appearances on thermoplastic BMG or high-density nano-protuberances from randomly distributed embedded nano-crystallites with average sizes below 200 nm on the recrystallized alloy. Upon ultrashort pulse irradiation employing linearly polarized 50 fs, 800 nm laser pulses, the surfaces show a range of nanoscale organized features. The change of topology was then followed under multiple pulse irradiation at fluences around and below the single pulse threshold. While the former material (Zr-BMG) shows a specific high quality arrangement of standard ripples around the laser wavelength, the latter (Zr-CA) demonstrates strong predisposition to form high spatial frequency rippled structures (HSFL). We discuss electromagnetic scenarios assisting their formation based on near-field interaction between particles and field-enhancement leading to structure linear growth. Finite-difference-time-domain simulations outline individual and collective effects of nanoparticles on electromagnetic energy modulation and the feedback processes in the formation of HSFL structures with correlation to regular ripples (LSFL). (C) 2016 Optical Society of America
入藏号: WOS:000377467800025
PubMed ID: 27410083
作者识别号:
作者        ResearcherID 号        ORCID 号
Colombier, Jean-Philippe         B-8884-2012         0000-0001-8462-7019
ISSN: 1094-4087
第 135 条,共 261 条
标题: Theoretical and experimental analysis of excessively tilted fiber gratings
作者: Yan, ZJ (Yan, Zhijun); Wang, HS (Wang, Hushan); Wang, CL (Wang, Changle); Sun, ZY (Sun, Zhongyuan); Yin, GL (Yin, Guolu); Zhou, KM (Zhou, Kaiming); Wang, YS (Wang, Yishan); Zhao, W (Zhao, Wei); Zhang, L (Zhang, Lin)
来源出版物: OPTICS EXPRESS 卷: 24 期: 11 页: 2107-2115 DOI: 10.1364/OE.24.012107 出版年: MAY 30 2016
摘要: We have theoretically and experimentally investigated the dual-peak feature of tilted fiber gratings with excessively tilted structure (named as Ex-TFGs). We have explained the dual-peak feature by solving eigenvalue equations for TM0m and TE0m of a circular waveguide, in which the TE (transverse electric) and TM (transverse magnetic) core modes are coupled into TE and TM cladding modes, respectively. Meanwhile, in the experiment, we have verified that one of the dual peaks at the shorter wavelength is due to the TM mode coupling whereas the other one at the longer wavelength arises from TE mode coupling when a linearly polarized light launched into the Ex-TFG. We have also investigated the peak separation of TE and TM cladding mode for different surrounding medium refractive indexes (SRI), revealed that the dual peaks separation is decreasing as increasing of SRI, which agrees very well with the theoretical analysis results. (C) 2016 Optical Society of America
入藏号: WOS:000377467800073
PubMed ID: 27410131
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhou, Kaiming         E-5903-2011         0000-0002-6011-1912
Yin, Guolu         D-3664-2014         0000-0002-8004-4198
ISSN: 1094-4087
第 136 条,共 261 条
标题: Watt-level passively Q-switched heavily Er3+-doped ZBLAN fiber laser with a semiconductor saturable absorber mirror
作者: Shen, YL (Shen, Yanlong); Wang, YS (Wang, Yishan); Luan, KP (Luan, Kunpeng); Huang, K (Huang, Ke); Tao, MM (Tao, Mengmeng); Chen, HW (Chen, Hongwei); Yi, AP (Yi, Aiping); Feng, GB (Feng, Guobin); Si, JH (Si, Jinhai)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 26659 DOI: 10.1038/srep26659 出版年: MAY 26 2016
摘要: A diode-cladding pumped mid-infrared passively Q-switched Er3+-doped ZBLAN fiber laser with an average output power of watt-level based on a semiconductor saturable absorber mirror (SESAM) is demonstrated. Stable pulse train was produced at a slope efficiency of 17.8% with respect to launched pump power. The maximum average power of 1.01 W at a repetition rate of 146.3 kHz was achieved with a corresponding pulse energy of 6.9 mu J, from which the maximum peak power was calculated to be 21.9 W. To the best of our knowledge, the average power and the peak power are the highest in 3 mu m region passively Q-switched fiber lasers. The influence of gain fiber length on the operation regime of the fiber laser has been investigated in detail.
入藏号: WOS:000376584900001
PubMed ID: 27225029
ISSN: 2045-2322
第 137 条,共 261 条
标题: Thin film wavelength converters for photonic integrated circuits
作者: Chang, L (Chang, Lin); Li, YF (Li, Yifei); Volet, N (Volet, Nicolas); Wang, LR (Wang, Leiran); Peters, J (Peters, Jon); Bowers, JE (Bowers, John E.)
来源出版物: OPTICA 卷: 3 期: 5 页: 531-535 DOI: 10.1364/OPTICA.3.000531 出版年: MAY 20 2016
摘要: Quasi-phase-matched (QPM) wavelength converters are highly desirable for emerging nonlinear optics applications in photonic integrated circuits, but available waveguide and quasi-phase-matching technologies have so far constrained their realization. In this work, we present a periodically poled lithium niobate (LN) waveguide on a silicon nitride-thin film LN platform. It contains a submicrometer waveguide core for enhancing nonlinear interactions that is more than one order of magnitude smaller than those of previous QPM waveguides. Periodic poling was applied directly to the thin film LN for quasi-phase-matching by a new surface poling technology. We demonstrated 160% W-1.cm(-2) normalized efficiency for second harmonic generation at 1530 nm with ultralow propagation loss (0.3 dB/cm) in the telecom band. This highly efficient and compact wavelength converter has the potential for straightforward integration with various photonic platforms, e.g., on-chip microsystems such as optical communication networks, quantum storage, and optical frequency referencing. (C) 2016 Optical Society of America
入藏号: WOS:000376395400012
ISSN: 2334-2536
第 138 条,共 261 条
标题: Effects of Laser Repetition Rate and Fluence on Micromachining of TiC Ceramic
作者: Zhang, Y (Zhang, Ying); Wang, YQ (Wang, Yuqian); Zhang, JZ (Zhang, Junzhan); Liu, YS (Liu, Yongsheng); Yang, XJ (Yang, Xiaojun); Li, WN (Li, Weinan)
来源出版物: MATERIALS AND MANUFACTURING PROCESSES 卷: 31 期: 7 页: 832-837 DOI: 10.1080/10426914.2015.1037916 出版年: MAY 18 2016
摘要: Micromachining of titanium carbide (TiC) ceramic is very difficult because of its high hardness and brittleness. Femtosecond pulsed laser was employed to process circular rings on the surface of TiC ceramic. The interaction area between femtosecond laser pulses and TiC at different laser repetition rates and fluences was studied. Morphology and composition of irradiated area were analyzed by scanning electron microscope, energy dispersive spectroscopy, and Raman spectrum. The results indicated that the radius of outer circle was close to the intended radius. Laser fluence had obvious effects on the radius and width of circular rings, compared to laser repetition rate. The width of circular rings increased rapidly with increasing laser fluence from 2.55x10(-2) to 1.27x10(-1)J/mm(2), and then stabilized at around 40 mu m when laser fluence was above 7.64x10(-1)J/mm(2). The surface of circular rings was characterized by ripples at the lower laser fluence. With increasing laser fluence, four kinds of typical morphology were observed, including ripples, cauliflower-like particles, ball-like particles, and deposited oxide layer. Ball-like particles contained high concentration of titanium, which came from melt ball splashing from ablation area. The others came from the different oxidation stages occurred on the surface of TiC sample.
入藏号: WOS:000372033900002
ISSN: 1042-6914
eISSN: 1532-2475
第 139 条,共 261 条
标题: Graphene-clad microfibre saturable absorber for ultrafast fibre lasers
作者: Liu, XM (Liu, X. M.); Yang, HR (Yang, H. R.); Cui, YD (Cui, Y. D.); Chen, GW (Chen, G. W.); Yang, Y (Yang, Y.); Wu, XQ (Wu, X. Q.); Yao, XK (Yao, X. K.); Han, DD (Han, D. D.); Han, XX (Han, X. X.); Zeng, C (Zeng, C.); Guo, J (Guo, J.); Li, WL (Li, W. L.); Cheng, G (Cheng, G.); Tong, LM (Tong, L. M.)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 26024 DOI: 10.1038/srep26024 出版年: MAY 16 2016
摘要: Graphene, whose absorbance is approximately independent of wavelength, allows broadband light-matter interactions with ultrafast responses. The interband optical absorption of graphene can be saturated readily under strong excitation, thereby enabling scientists to exploit the photonic properties of graphene to realize ultrafast lasers. The evanescent field interaction scheme of the propagating light with graphene covered on a D-shaped fibre or microfibre has been employed extensively because of the nonblocking configuration. Obviously, most of the fibre surface is unused in these techniques. Here, we exploit a graphene-clad microfibre (GCM) saturable absorber in a mode-locked fibre laser for the generation of ultrafast pulses. The proposed all-surface technique can guarantee a higher efficiency of light-graphene interactions than the aforementioned techniques. Our GCM-based saturable absorber can generate ultrafast optical pulses within 1.5 mu m. This saturable absorber is compatible with current fibre lasers and has many merits such as low saturation intensities, ultrafast recovery times, and wide wavelength ranges. The proposed saturable absorber will pave the way for graphene-based wideband photonics.
入藏号: WOS:000375923900002
PubMed ID: 27181419
ISSN: 2045-2322
第 140 条,共 261 条
标题: Passively Q-switched nd:YAG laser via a WS2 saturable absorber
作者: Wang, X (Wang, Xi); Wang, YG (Wang, Yonggang); Duan, LN (Duan, Lina); Li, L (Li, Lu); Sun, H (Sun, Hang)
来源出版物: OPTICS COMMUNICATIONS 卷: 367 页: 234-238 DOI: 10.1016/j.optcom.2016.01.066 出版年: MAY 15 2016
摘要: In this work, we report a passively Q-switched Nd:YAG laser at 1064 nm by using WS2 solution as the saturable absorber (SA). The WS2 solution with different concentrations (0.25, 0.5, and 1 mg/ml) were fabricated by the liquid-phase-exfoliated method and injected into quartz cells. Such liquid absorbers have the virtues of adjustable optical absorption, high heat dissipation and non-contact damage. By inserting those WS2 solutions in the laser cavity, stable Q-switched laser operations were obtained. The corresponding pulse duration as short as 922 ns was obtained. The result shows that the WS2 material can be act as absorber for solid-state lasers. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000370127300035
ISSN: 0030-4018
eISSN: 1873-0310
第 141 条,共 261 条
标题: Cooled Dyson long-wave infrared push-broom imaging spectrometer by re-imaging
作者: Sun, JY (Sun, Jiayin); Liu, Y (Liu, Ying); Jiang, Y (Jiang, Yang); Li, C (Li, Chun); Sun, Q (Sun, Qiang); Hu, XR (Hu, Xinrong)
来源出版物: OPTICS COMMUNICATIONS 卷: 367 页: 274-278 DOI: 10.1016/j.optcom.2016.01.067 出版年: MAY 15 2016
摘要: A cooled long-wave infrared push-broom imaging spectrometer with an F-number of 2 was designed based on the Dyson configuration. A three-mirror off-axis aspherical optical system that provided excellent slit-shaped images was selected as the fore telescope objective. The re-imaging method was applied to obtain a cold stop efficiency of 100%, and the corrector lens in traditional Dyson imaging spectrometers was replaced with re-imaging lenses to correct spherical aberrations. The designed imaging spectrometer provided a spectral resolution of 25 nm at a range of 8-12 mu m and possessed a relatively small volume. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000370127300042
ISSN: 0030-4018
eISSN: 1873-0310
第 142 条,共 261 条
标题: High-Quality Hollow Closed-Pore Silica Antireflection Coatings Based on Styrene-Acrylate Emulsion @ Organic-Inorganic Silica Precursor
作者: Guo, ZL (Guo, Zhaolong); Zhao, HX (Zhao, Haixin); Zhao, W (Zhao, Wei); Wang, T (Wang, Tao); Kong, DP (Kong, Depeng); Chen, TJ (Chen, Taojing); Zhang, XY (Zhang, Xiaoyan)
来源出版物: ACS APPLIED MATERIALS & INTERFACES 卷: 8 期: 18 页: 11796-11805 DOI: 10.1021/acsami.6b02192 出版年: MAY 11 2016
摘要: Making use of a facile and low-cost way for the preparation of a hierarchically organized novel hollow closed pore silica antireflective coating (CHAR) with tailored optical properties and a mechanical reliability is of great interest in the field of solar photovoltaic technology. The process mainly contains two aspects: (1) a styrene acrylate emulsion @ organic inorganic silica precursor (SA@OISP) core/shell hierarchical nanostructure, consisting of a sacrificial styrene acrylate (SA) primary template, was fabricated using a sol-gel method; (2) the self-assembly of the nanostructures leads to SA@ OISP nanospheres forming the high-quality hollow closed-pore silica antireflection coating (CHAR) by a dip-coating process and a subsequent calcination treatment. The resulting SA@OISP nanospheres have a mean diameter of 65.2 nm and contained a SA soft core with a mean diameter of approximately 54.8 nm and an organic inorganic silica precursor (OISP) shell with a thickness of approximately 6-10 nm. Furthermore, the prepared CHAR film exhibited a high transmittance and good ruggedness. An average transmittance (T-AV) of 97.64% was obtained, and the value is close to the ideal single-layered antireflection coating (98.09%) over a broad range of wavelengths (from 380 to 1100 nm). The CHAR film showed a stable T-AV, with attenuation values of less than 0.8% and 0.43% after the abrasion test and the damp heat test, respectively. The conversion efficiency of the CHAR coating cover solar modules tends to be increased by 3.75%. The promising results obtained in this study suggest that the CHAR film was considered as an essential component of the solar module and were expected to provide additional solar energy harvest under extreme outdoor climates.
入藏号: WOS:000375521000069
PubMed ID: 27104837
ISSN: 1944-8244
第 143 条,共 261 条
标题: Deblurring for spatial and temporal varying motion with optical computing
作者: Xiao, X (Xiao, Xiao); Xue, DF (Xue, Dongfeng); Hui, Z (Hui, Zhao)
来源出版物: OPTICAL ENGINEERING 卷: 55 期: 5 文献号: 053103 DOI: 10.1117/1.OE.55.5.053103 出版年: MAY 2016
摘要: A way to estimate and remove spatially and temporally varying motion blur is proposed, which is based on an optical computing system. The translation and rotation motion can be independently estimated from the joint transform correlator (JTC) system without iterative optimization. The inspiration comes from the fact that the JTC system is immune to rotation motion in a Cartesian coordinate system. The work scheme of the JTC system is designed to keep switching between the Cartesian coordinate system and polar coordinate system in different time intervals with the ping-pang handover. In the ping interval, the JTC system works in the Cartesian coordinate system to obtain a translation motion vector with optical computing speed. In the pang interval, the JTC system works in the polar coordinate system. The rotation motion is transformed to the translation motion through coordinate transformation. Then the rotation motion vector can also be obtained from JTC instantaneously. To deal with continuous spatially variant motion blur, submotion vectors based on the projective motion path blur model are proposed. The submotion vectors model is more effective and accurate at modeling spatially variant motion blur than conventional methods. The simulation and real experiment results demonstrate its overall effectiveness. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000377588800003
作者识别号:
作者        ResearcherID 号        ORCID 号
Xue, Dongfeng         E-5881-2011         0000-0002-0748-0962
ISSN: 0091-3286
eISSN: 1560-2303
第 144 条,共 261 条
标题: In Situ Surface Assembly Derived Ultralow Refractive Index MgF2-SiO2 Hybrid Film for Tri-Layer Broadband Antireflective Coating
作者: Cui, XM (Cui, Xinmin); Ding, RM (Ding, Ruimin); Wang, MC (Wang, Mengchao); Zhang, C (Zhang, Cong); Zhang, C (Zhang, Ce); Zhang, J (Zhang, Jing); Xu, Y (Xu, Yao)
来源出版物: ADVANCED OPTICAL MATERIALS 卷: 4 期: 5 页: 722-730 DOI: 10.1002/adom.201500595 出版年: MAY 2016
摘要: For the broadband antireflective (AR) coating working in specific wavelengths, the precise control over refractive index and film thickness of each layer is critical to guarantee the peak position locating at the targeted wavelengths. In this paper, a simple sol-gel procedure without post-treatment is used to prepare MgF2-SiO2 hybrid coating with tunable refractive index for the fabrication of tri-layer tri-wavelength broadband AR coating. The MgF2-SiO2 coating with ultralow refractive index of 1.12 is realized through in situ surface assembly of negatively charged silanol groups on vesicle-like MgF2 particles to obtain porous crosslinking structure. The electrostatic attraction between the negatively charged silanol groups and positively charged MgF2 colloidal particles plays a key role. Furthermore, the MgF2-SiO2 coating with a wide range of refractive index between 1.20 and 1.44 is achieved by adjusting the addition amount of acid-catalyzed silica sol into the vesicle-like MgF2 sol. According to the theoretical design, a tri-layer broadband AR coating with refractive index model of 1.12/1.26/1.36 is prepared, which can enhance the transmittance of quartz substrate to near 100% simultaneously at 351, 527, and 1053 nm.
入藏号: WOS:000377598900013
ISSN: 2195-1071
第 145 条,共 261 条
标题: Implementation of dispersion-free slow acoustic wave propagation and phase engineering with helical-structured metamaterials
作者: Zhu, XF (Zhu, Xuefeng); Li, K (Li, Kun); Zhang, P (Zhang, Peng); Zhu, J (Zhu, Jie); Zhang, JT (Zhang, Jintao); Tian, C (Tian, Chao); Liu, SC (Liu, Shengchun)
来源出版物: NATURE COMMUNICATIONS 卷: 7 文献号: 11731 DOI: 10.1038/ncomms11731 出版年: MAY 2016
摘要: The ability to slow down wave propagation in materials has attracted significant research interest. A successful solution will give rise to manageable enhanced wave-matter interaction, freewheeling phase engineering and spatial compression of wave signals. The existing methods are typically associated with constructing dispersive materials or structures with local resonators, thus resulting in unavoidable distortion of waveforms. Here we show that, with helical-structured acoustic metamaterials, it is now possible to implement dispersion-free sound deceleration. The helical-structured metamaterials present a non-dispersive high effective refractive index that is tunable through adjusting the helicity of structures, while the wavefront revolution plays a dominant role in reducing the group velocity. Finally, we numerically and experimentally demonstrate that the helical-structured metamaterials with designed inhomogeneous unit cells can turn a normally incident plane wave into a self-accelerating beam on the prescribed parabolic trajectory. The helical-structured metamaterials will have profound impact to applications in explorations of slow wave physics.
入藏号: WOS:000376206500001
PubMed ID: 27198887
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhu, Jie                  0000-0002-2547-7775
ISSN: 2041-1723
第 146 条,共 261 条
标题: Pixel-to-Model Distance for Robust Background Reconstruction
作者: Yang, L (Yang, Lu); Cheng, H (Cheng, Hong); Su, JN (Su, Jianan); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 卷: 26 期: 5 页: 903-916 DOI: 10.1109/TCSVT.2015.2424052 出版年: MAY 2016
摘要: Background information is crucial for many video surveillance applications such as object detection and scene understanding. In this paper, we present a novel pixel-to-model (P2M) paradigm for background modeling and restoration in surveillance scenes. In particular, the proposed approach models the background with a set of context features for each pixel, which are compressively sensed from local patches. We determine whether a pixel belongs to the background according to the minimum P2M distance, which measures the similarity between the pixel and its background model in the space of compressive local descriptors. The pixel feature descriptors of the background model are properly updated with respect to the minimum P2M distance. Meanwhile, the neighboring background model will be renewed according to the maximum P2M distance to handle ghost holes. The P2M distance plays an important role of background reliability in the 3-D spatial-temporal domain of surveillance videos, leading to the robust background model and recovered background videos. We applied the proposed P2M distance for foreground detection and background restoration on synthetic and real-world surveillance videos. Experimental results show that the proposed P2M approach outperforms the state-of-the-art approaches both in indoor and outdoor surveillance scenes.
入藏号: WOS:000375707500009
ISSN: 1051-8215
eISSN: 1558-2205
第 147 条,共 261 条
标题: Superpixel Optimization Using Higher Order Energy
作者: Peng, JT (Peng, Jianteng); Shen, JB (Shen, Jianbing); Yao, A (Yao, Angela); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 卷: 26 期: 5 页: 917-927 DOI: 10.1109/TCSVT.2015.2430631 出版年: MAY 2016
摘要: A novel superpixel extraction algorithm using a higher order energy optimization framework is proposed in this paper. We first adopt the k-means clustering technique to quickly get an initial superpixel result. Then a higher order energy function is employed to optimize and refine these initial superpixels. We use a more general higher order energy function that includes a first-order data term, a second-order smoothness term, and a higher order term. The presegments are employed to provide the prior information of sufficient edges and segment regions for our higher order energy term. According to the texture measurement in different local regions, our algorithm adaptively computes the proper ratios of different energy terms to obtain a better superpixel performance. The experimental results demonstrate that our method using the higher order energy generates better results with well-aligned boundaries and homogeneous effects than the existing superpixel algorithms.
入藏号: WOS:000375707500010
ISSN: 1051-8215
eISSN: 1558-2205
第 148 条,共 261 条
标题: Video Supervoxels Using Partially Absorbing Random Walks
作者: Liang, YL (Liang, Yuling); Shen, JB (Shen, Jianbing); Dong, XP (Dong, Xingping); Sun, HQ (Sun, Hanqiu); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 卷: 26 期: 5 页: 928-938 DOI: 10.1109/TCSVT.2015.2406232 出版年: MAY 2016
摘要: Supervoxels have been widely used as a preprocessing step to exploit object boundaries to improve the performance of video processing tasks. However, most of the traditional supervoxel algorithms do not perform well in regions with complex textures or weak boundaries. These methods may generate supervoxels with overlapping boundaries. In this paper, we present the novel video supervoxel generation algorithm using partially absorbing random walks to get more accurate supervoxels in these regions. Our spatial-temporal framework is introduced by making full use of the appearance and motion cues, which effectively exploits the temporal consistency in video sequence. Moreover, we build a novel Laplacian optimization structure using two adjacent frames to make our approach more efficient. Experimental results demonstrated that our method achieved better performance than the state-of-the-art supervoxel algorithms.
入藏号: WOS:000375707500011
ISSN: 1051-8215
eISSN: 1558-2205
第 149 条,共 261 条
标题: Influence of longitudinal argon flow on DC glow discharge at atmospheric pressure
作者: Zhu, S (Zhu, Sha); Jiang, WM (Jiang, Weiman); Tang, J (Tang, Jie); Xu, YG (Xu, Yonggang); Wang, YS (Wang, Yishan); Zhao, W (Zhao, Wei); Duan, YX (Duan, Yixiang)
来源出版物: JAPANESE JOURNAL OF APPLIED PHYSICS 卷: 55 期: 5 文献号: 056202 DOI: 10.7567/JJAP.55.056202 出版年: MAY 2016
摘要: A one-dimensional self-consistent fluid model was employed to investigate the influence of longitudinal argon flow on the DC glow discharge at atmospheric pressure. It is found that the charges exhibit distinct dynamic behaviors at different argon flow velocities, accompanied by a considerable change in the discharge structure. The positive argon flow allows for the reduction of charge densities in the positive column and negative glow regions, and even leads to the disappearance of negative glow. The negative argon flow gives rise to the enhancement of charge densities in the positive column and negative glow regions. These observations are attributed to the fact that the gas flow convection influences the transport of charges through different manners by comparing the argon flow velocity with the ion drift velocity. The findings are important for improving the chemical activity and work efficiency of the plasma source by controlling the gas flow in practical applications. (C) 2016 The Japan Society of Applied Physics
入藏号: WOS:000374506700022
ISSN: 0021-4922
eISSN: 1347-4065
第 150 条,共 261 条
标题: Thermal tunability of photonic bandgaps in liquid crystal filled polymer photonic crystal fiber
作者: Wang, DD (Wang, Doudou); Chen, GX (Chen, Guoxiang); Wang, LL (Wang, Lili)
来源出版物: OPTICAL FIBER TECHNOLOGY 卷: 29 页: 95-99 DOI: 10.1016/j.yofte.2016.04.004 出版年: MAY 2016
摘要: A highly tunable bandgap-guiding polymer photonic crystal fiber is designed by infiltrating the cladding air holes with liquid crystal 5CB. Structural parameter dependence and thermal tunability of the photonic bandgaps, mode properties and confinement losses of the designed fiber are investigated. Bandgaps red shift as the temperature goes up. Average thermal tuning sensitivity of 30.9 nm/degrees C and 20.6 nm/degrees C is achieved around room temperature for the first and second photonic bandgap, respectively. Our results provide theoretical references for applications of polymer photonic crystal fiber in sensing and tunable fiber-optic devices. (C) 2016 Elsevier Inc. All rights reserved.
入藏号: WOS:000375860700014
ISSN: 1068-5200
eISSN: 1095-9912

第 151 条,共 261 条
标题: Dual-wavelength synchronous mode-locked Yb:LSO laser using a double-walled carbon nanotube saturable absorber
作者: Feng, C (Feng, Chao); Hou, W (Hou, Wei); Yang, JM (Yang, Jimin); Liu, J (Liu, Jie); Zheng, LH (Zheng, Lihe); Su, LB (Su, Liangbi); Xu, J (Xu, Jun); Wang, YG (Wang, Yonggang)
来源出版物: APPLIED OPTICS 卷: 55 期: 13 页: 3639-3644 DOI: 10.1364/AO.55.003639 出版年: MAY 1 2016
摘要: A dual-wavelength, passively mode-locked Yb:LSO laser was demonstrated using a double-walled carbon nanotube as a saturable absorber. The maximum average output power of the laser was 1.34 W at the incident pump power of 9.94 W. The two central wavelengths were 1057 and 1058 nm. The corresponding pulse duration of the autocorrelation interference pattern was about 15 ps, while the beat pulse repetition rate was 0.17 THz and the width of one beat pulse about 2 ps. When the incident pump power was above 10.25 W, a multiwavelength mode-locked oscillation phenomenon was observed. After employing a pair of SF10 prisms, a 1058.7 nm single-wavelength mode-locked laser was obtained with a pulse width of 7 ps. (C) 2016 Optical Society of America
入藏号: WOS:000375154900039
PubMed ID: 27140382
ISSN: 1559-128X
eISSN: 2155-3165
第 152 条,共 261 条
标题: Systematic experimental study on a highly efficient terahertz source based on two-color laser-induced air plasma
作者: Xie, J (Xie, Jun); Fan, WH (Fan, Wen-Hui); Chen, X (Chen, Xu)
来源出版物: LASER PHYSICS 卷: 26 期: 5 文献号: 055002 DOI: 10.1088/1054-660X/26/5/055002 出版年: MAY 2016
摘要: In this paper, highly efficient terahertz radiation generated by two-color femtosecond laser-induced air plasma is reported. A number of variables that can obviously influence terahertz generation and detection have been investigated systematically. The dependence on experimental parameters, including pulse energy, the rotation angle of beta-barium boron oxide (BBO) crystal, the distance between BBO crystal and laser-induced plasma, focal length, chopper frequency, and detection angle are presented, and the optimal values of these parameters have also been obtained experimentally. Finally, a highly efficient terahertz source has been achieved and can be utilized to carry out further investigation on terahertz sensing, spectroscopy, and imaging.
入藏号: WOS:000375178700002
ISSN: 1054-660X
eISSN: 1555-6611
第 153 条,共 261 条
标题: Perspective of monochromatic gamma-ray line detection with the High Energy cosmic-Radiation Detection (HERD) facility onboard China's space station
作者: Huang, XY (Huang, Xiaoyuan); Lamperstorfer, AS (Lamperstorfer, Anna S.); Tsai, YLS (Tsai, Yue-Lin Sming); Xu, M (Xu, Ming); Yuan, Q (Yuan, Qiang); Chang, J (Chang, Jin); Dong, YW (Dong, Yong-Wei); Hu, BL (Hu, Bing-Liang); Lu, JG (Lu, Jun-Guang); Wang, L (Wang, Le); Wu, BB (Wu, Bo-Bing); Zhang, SN (Zhang, Shuang-Nan)
来源出版物: ASTROPARTICLE PHYSICS 卷: 78 页: 35-42 DOI: 10.1016/j.astropartphys.2016.02.003 出版年: MAY 2016
摘要: HERD is the High Energy cosmic-Radiation Detection instrument proposed to operate onboard China's space station in the 2020s. It is designed to detect energetic cosmic ray nuclei, leptons and photons with a high energy resolution (similar to 1% for electrons and photons and 20% for nuclei) and a large geometry factor (>3 m(2) sr for electrons and diffuse photons and > [2]m(2) sr for nuclei). In this work we discuss the capability of HERD to detect monochromatic gamma-ray lines, based on simulations of the detector performance. It is shown that HERD will be one of the most sensitive instruments for monochromatic gamma-ray searches at energies between similar to 10 to a few hundred GeV. Above hundreds of GeV, Cherenkov telescopes will be more sensitive due to their large effective area. As a specific example, we show that a good portion of the parameter space of a supersymmetric dark matter model can be probed with HERD. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000374612500003
作者识别号:
作者        ResearcherID 号        ORCID 号
Tsai, Yue-Lin Sming                  0000-0002-7275-8561
ISSN: 0927-6505
eISSN: 1873-2852
第 154 条,共 261 条
标题: Tunable terahertz generation via a cascaded optical parametric device
作者: Huang, N (Huang, Nan); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Wang, ZL (Wang, Zhaolu); Li, SP (Li, Shaopeng); Han, J (Han, Jing)
来源出版物: LASER PHYSICS LETTERS 卷: 13 期: 5 文献号: 055802 DOI: 10.1088/1612-2011/13/5/055802 出版年: MAY 2016
摘要: A compact cascaded optical parametric device generating a coherent pulse terahertz (THz) wave is demonstrated. The terahertz parametric oscillator (TPO) and the difference frequency generation (DFG) are designed for cascaded operation use with two outputs producing tunable THz wavelengths. From the first optical parametric device, a TPO with a MgO: LiNbO3 crystal pumped by a Q switch laser of 1.064 mu m, 1.8 mJ idler pulse and 5.5 mJ residual pump pulse is obtained. Both of the two beams are employed as the pump and signal beams in the second optical parametric device DFG with a GaSe crystal. More than 0.6 mu J and about 2.1 ns THz pulse at 183 mu m is achieved from the DFG. A tunable THz source in the range 104-226 mu m via tuning the external phase matching (PM) angles of the TPO and the DFG flexibly under room temperature is obtained. The observed tunable THz wavelengths from the DFG are the same as those from the TPO.
入藏号: WOS:000375179300019
ISSN: 1612-2011
eISSN: 1612-202X
第 155 条,共 261 条
标题: A-Optimal Projection for Image Representation
作者: He, XF (He, Xiaofei); Zhang, CY (Zhang, Chiyuan); Zhang, LJ (Zhang, Lijun); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 卷: 38 期: 5 页: 1009-1015 DOI: 10.1109/TPAMI.2015.2439252 出版年: MAY 2016
摘要: We consider the problem of image representation from the perspective of statistical design. Recent studies have shown that images are possibly sampled from a low dimensional manifold despite of the fact that the ambient space is usually very high dimensional. Learning low dimensional image representations is crucial for many image processing tasks such as recognition and retrieval. Most of the existing approaches for learning low dimensional representations, such as principal component analysis (PCA) and locality preserving projections (LPP), aim at discovering the geometrical or discriminant structures in the data. In this paper, we take a different perspective from statistical experimental design, and propose a novel dimensionality reduction algorithm called A-Optimal Projection (AOP). AOP is based on a linear regression model. Specifically, AOP finds the optimal basis functions so that the expected prediction error of the regression model can be minimized if the new representations are used for training the model. Experimental results suggest that the proposed approach provides a better representation and achieves higher accuracy in image retrieval.
入藏号: WOS:000374164700013
ISSN: 0162-8828
eISSN: 1939-3539
第 156 条,共 261 条
标题: Aging Face Recognition: A Hierarchical Learning Model Based on Local Patterns Selection
作者: Li, ZF (Li, Zhifeng); Gong, DH (Gong, Dihong); Li, XL (Li, Xuelong); Tao, DC (Tao, Dacheng)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 5 页: 2146-2154 DOI: 10.1109/TIP.2016.2535284 出版年: MAY 2016
摘要: Aging face recognition refers to matching the same person's faces across different ages, e.g., matching a person's older face to his (or her) younger one, which has many important practical applications, such as finding missing children. The major challenge of this task is that facial appearance is subject to significant change during the aging process. In this paper, we propose to solve the problem with a hierarchical model based on two-level learning. At the first level, effective features are learned from low-level microstructures, based on our new feature descriptor called local pattern selection (LPS). The proposed LPS descriptor greedily selects low-level discriminant patterns in a way, such that intra-user dissimilarity is minimized. At the second level, higher level visual information is further refined based on the output from the first level. To evaluate the performance of our new method, we conduct extensive experiments on the MORPH data set (the largest face aging data set available in the public domain), which show a significant improvement in accuracy over the state-of-the-art methods.
入藏号: WOS:000373131000014
PubMed ID: 26930681
ISSN: 1057-7149
eISSN: 1941-0042
第 157 条,共 261 条
标题: Analysis of dual-end-pumped Nd3+-doped index-crossover gain guided-index antiguided fiber laser
作者: Shen, X (Shen, Xiao); Wei, W (Wei, Wei); Zou, H (Zou, Hui); Zhang, LL (Zhang, Liaolin)
来源出版物: OPTICS COMMUNICATIONS 卷: 366 页: 205-209 DOI: 10.1016/j.optcom.2015.12.063 出版年: MAY 1 2016
摘要: A dual-end pumped Nd3+-doped index-crossover gain guided-index antiguided (IGG-IAG) fiber laser is analyzed in theory. Pump light propagation and output laser characteristics are both explored by solving the related rate equations. Simulation results show that pump power confined in the IGG-IAG fiber core is larger and more uniform than that of the gain-guided and index-antiguided(GG-IAG) fiber, and the optimum fiber length and the output power of the IGG-IAG fiber laser are both larger than that of GG-IAG fiber laser. The relationship between threshold pump power and doped concentration, fiber length, fiber radius is researched respectively. The analysis results give out a method for the optimal design of the IGG-IAG fiber laser. (C) 2015 Elsevier B.V. All rights reserved.
入藏号: WOS:000369368700034
ISSN: 0030-4018
eISSN: 1873-0310
第 158 条,共 261 条
标题: Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers
作者: Li, XH (Li, Xiaohui); Wu, K (Wu, Kan); Sun, ZP (Sun, Zhipei); Meng, B (Meng, Bo); Wang, YG (Wang, Yonggang); Wang, YS (Wang, Yishan); Yu, XC (Yu, Xuechao); Yu, X (Yu, Xia); Zhang, Y (Zhang, Ying); Shum, PP (Shum, Perry Ping); Wang, QJ (Wang, Qi Jie)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 25266 DOI: 10.1038/srep25266 出版年: APR 29 2016
摘要: Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wallpaper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers.
入藏号: WOS:000375113400003
PubMed ID: 27126900
作者识别号:
作者        ResearcherID 号        ORCID 号
Wang, Qi Jie         E-6987-2010         
Shum , Ping         A-5091-2011         0000-0003-1391-4736
Sun, Zhipei         G-2442-2013         
Li, Xiaohui         J-9580-2012         0000-0002-5600-3820
ISSN: 2045-2322
第 159 条,共 261 条
标题: All-optical control of microfiber resonator by graphene's photothermal effect
作者: Wang, YD (Wang, Yadong); Gan, XT (Gan, Xuetao); Zhao, CY (Zhao, Chenyang); Fang, L (Fang, Liang); Mao, D (Mao, Dong); Xu, YP (Xu, Yiping); Zhang, FL (Zhang, Fanlu); Xi, TL (Xi, Teli); Ren, LY (Ren, Liyong); Zhao, JL (Zhao, Jianlin)
来源出版物: APPLIED PHYSICS LETTERS 卷: 108 期: 17 文献号: 171905 DOI: 10.1063/1.4947577 出版年: APR 25 2016
摘要: We demonstrate an efficient all-optical control of microfiber resonator assisted by graphene's photothermal effect. Wrapping graphene onto a microfiber resonator, the light-graphene interaction can be strongly enhanced via the resonantly circulating light, which enables a significant modulation of the resonance with a resonant wavelength shift rate of 71 pm/mW when pumped by a 1540 nm laser. The optically controlled resonator enables the implementation of low threshold optical bistability and switching with an extinction ratio exceeding 13 dB. The thin and compact structure promises a fast response speed of the control, with a rise (fall) time of 294.7 mu s (212.2 mu s) following the 10%-90% rule. The proposed device, with the advantages of compact structure, all-optical control, and low power acquirement, offers great potential in the miniaturization of active in-fiber photonic devices. Published by AIP Publishing.
入藏号: WOS:000375846600018
作者识别号:
作者        ResearcherID 号        ORCID 号
Mao, 8731629         G-5113-2014         0000-0002-5744-6316
mao, maodong         K-6333-2016         
Ren, Liyong         F-5518-2014         0000-0002-7547-7511
ISSN: 0003-6951
eISSN: 1077-3118
第 160 条,共 261 条
标题: Study on the methods of calibrating spectral line position of interference imaging spectrometer
作者: Wei, YT (Wei Yu-Tong); Liu, SK (Liu Shang-Kuo); Yan, TY (Yan Ting-Yu); Li, QW (Li Qi-Wei)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 8 文献号: 080601 DOI: 10.7498/aps.65.080601 出版年: APR 20 2016
摘要: The principle of interference imaging spectrometer is presented. According to the drift of recovery spectral line position, two representative methods of calibrating the laboratory spectral line position are proposed, and the calibration results and their comparative analyses are given. One method of calibration is to correct the principle, which embarks from parameter selection of interference imaging spectrometer and the analysis of the reason why the spectral line position is drifted. Aiming at the problem that the position of spectral line changes with row, the correction scheme is given to improve the accuracy of spectral line position. For four given laser wavelengths, which are 543.5 nm, 594.1 nm, 612 nm, and 632.8 nm, the root-mean-square (RMS) error of spectral line position is reduced from 28.3914 to 5.5371 after calibration. For the interferometer system which has no dispersion, the accuracy of calibration is better than the dispersion system, and can be the same at all detected wavelengths. In this article, the calibration accuracy of long wave is better than that of short wave, which is dependent on the selection of the initial correction wavelength. This method achieves a kind of universality for interference imaging spectrometer and its calibration parameters provide a convenient way to analyze the instrument indexes. Another calibration method is data processing. It makes up the deficiencies of the method mentioned above: a large number of data are needed and the effect of calibration at short wave is not good enough. The RMS error of spectral line position is reduced to 0.9178, which proves that the calibration has a really high precision. This method is simple and can correct all the detected wavelengths and spectral lines by using two united formula. Though this method is not applicable for all the interference imaging spectrometers, the idea that makes hard things simple is deserving of our attention. We can use it in many other fields. The essence of the method is to change a variable quantity into a slowly varying quantity by algorithms, and then establish the relationship between the slowly varying quantity and the standard value. This idea can always make a substantial increase in efficiency of calibration and has a satisfied accuracy. Each of the two methods has advantages and disadvantages: which method we choose to use is dependent on the effect we want to achieve, and it is better to make their combination. This study provides a theoretical and practical guidance for study, design, modulation, experiment and engineering of interference imaging spectrometers.
入藏号: WOS:000380363400006
ISSN: 1000-3290
第 161 条,共 261 条
标题: Reduction of phase noise to amplitude noise conversion in silicon waveguide-based phase-sensitive amplification
作者: Ma, YH (Ma, Yonghua); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu)
来源出版物: APPLIED OPTICS 卷: 55 期: 12 页: 3140-3144 DOI: 10.1364/AO.55.003140 出版年: APR 20 2016
摘要: We use a vector phase sensitive amplification (PSA) scheme, which can eliminate the inherent phase noise (PN) to amplitude noise (AN) conversion in a conventional PSA process. A dispersion-engineered silicon strip waveguide is used to investigate the vector PSA scheme at the telecom wavelengths. The phase-dependent gain and phase-to-phase transfer functions as well as constellation diagram at different signal polarization states (SPSs) are numerically analyzed. It is found that the PN to AN conversion is completely suppressed when the SPS is identical to one of the pump polarization states. Moreover, the binary phase shift keying signal is regenerated by the proposed vector PSA scheme, and the error vector magnitude is calculated to assess the regeneration capacity. Our results have potential application in all-optical signal processing. (C) 2016 Optical Society of America
入藏号: WOS:000374388600035
PubMed ID: 27140079
ISSN: 1559-128X
eISSN: 2155-3165
第 162 条,共 261 条
标题: Numerical analysis of pulse signal restoration by stochastic resonance in a buckled microcavity
作者: Sun, H (Sun, Heng); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu); Han, J (Han, Jing)
来源出版物: APPLIED OPTICS 卷: 55 期: 12 页: 3351-3355 DOI: 10.1364/AO.55.003351 出版年: APR 20 2016
摘要: A novel scheme is proposed to restore weak pulse signals immersed in noise by stochastic resonance based on photothermal-effect-induced optical bistability in a buckled dome microcavity. The bistable properties of the dome microcavity are analyzed with different initial detuning wavelengths and effective cavity lengths, and bistable transmission can be obtained for input powers in submilliwatt range. A theoretical model is derived to interpret the nonlinear process of pulse signal recovery through double-well potential theory. The cross-correlation coefficient between output signals and pure input pulses is calculated to quantitatively analyze the influence of noise intensity on stochastic resonance. A cross-correlation gain of 7 is obtained, and the noise-hidden signal can be recovered effectively though the buckled dome microcavity with negligible distortion. The simulation results show the potential of using this structure to restore low-level or noise-hidden pulse signals in all-optical integrated systems. (C) 2016 Optical Society of America
入藏号: WOS:000374388600066
PubMed ID: 27140110
ISSN: 1559-128X
eISSN: 2155-3165
第 163 条,共 261 条
标题: Numerical analysis of the surface-conduction electron-emitter with a new configuration
作者: Shen, ZH (Shen, Zhihua); Wang, X (Wang, Xiao); Wu, SL (Wu, Shengli); Tian, JS (Tian, Jinshou)
来源出版物: MODERN PHYSICS LETTERS B 卷: 30 期: 10 文献号: 1650137 DOI: 10.1142/S0217984916501372 出版年: APR 20 2016
摘要: A new kind of surface -conduction electron -emitter (SCE) with a triangular dielectric layer under the conductive film is proposed. The influences of the vertex angle (theta) of the triangular dielectric layer and the anode voltage (U-a) on the electron emission efficiency and the focusing capability have been investigated with the finite integration technique (FIT). The numerical simulation results show that SCE with a small vertex angle guarantees higher electron emission efficiency even with a low anode voltage. But the focusing capability of the electron emitter will get worse when the theta or U-a becomes too small. Take both the electron emission efficiency and focusing capability into consideration, the structure with a vertex angle (theta) between 60 degrees-100 degrees and the anode voltage of 1500 V is suggested.
入藏号: WOS:000374854600012
ISSN: 0217-9849
eISSN: 1793-6640
第 164 条,共 261 条
标题: Lab-on-fiber electrophoretic trace mixture separating and detecting an optofluidic device based on a microstructured optical fiber
作者: Yang, XH (Yang, Xinghua); Guo, XH (Guo, Xiaohui); Li, S (Li, Song); Kong, DP (Kong, Depeng); Liu, ZH (Liu, Zhihai); Yang, J (Yang, Jun); Yuan, LB (Yuan, Libo)
来源出版物: OPTICS LETTERS 卷: 41 期: 8 页: 1873-1876 DOI: 10.1364/OL.41.001873 出版年: APR 15 2016
摘要: We report an in-fiber integrated electrophoretic trace mixture separating and detecting an optofluidic optical fiber sensor based on a specially designed optical fiber. In this design, rapid in situ separation and simultaneous detection of mixed analytes can be realized under electro-osmotic flow in the microstructured optical fiber. To visually display the in-fiber separating and detecting process, two common fluorescent indicators are adopted as the optofluidic analytes in the optical fiber. Results show that a trace amount of the mixture (0.15 mu L) can be completely separated within 3.5 min under a high voltage of 5 kV. Simultaneously, the distributed information of the separated analytes in the optical fiber can be clearly obtained by scanning along the optical fiber using a 355 nm laser. The emission from the analytes can be efficiently coupled into the inner core and guides to the remote end of the optical fiber. In addition, the thin cladding around the inner core in the optical fiber can prevent the fluorescent cross talk between the analytes in this design. Compared to previous optical fiber optofluidic devices, this device first realizes simultaneously separating treatment and the detection of the mixed samples in an optical fiber. Significantly, such an in-fiber integrated separating and detecting optofluidic device can find wide applications in various analysis fields involves mixed samples, such as biology, chemistry, and environment. (C) 2016 Optical Society of America
入藏号: WOS:000374391900047
PubMed ID: 27082367
作者识别号:
作者        ResearcherID 号        ORCID 号
Yang, jun         G-4446-2014         0000-0002-6805-4289
ISSN: 0146-9592
eISSN: 1539-4794
第 165 条,共 261 条
标题: PH-dependent morphology and its effect on the optical properties of LaF3:Nd nanocrystals
作者: Cui, XX (Cui, Xiaoxia); Guo, HT (Guo, Haitao); Wei, W (Wei, Wei); Hou, CQ (Hou, Chaoqi); Gao, F (Gao, Fei); Peng, B (Peng, Bo)
来源出版物: MATERIALS CHEMISTRY AND PHYSICS 卷: 173 页: 132-138 DOI: 10.1016/j.matchemphys.2016.01.048 出版年: APR 15 2016
摘要: Nd3+-doped LaF3 nanocrystals with different morphologies have been produced via solvothermal method at various pH values (1-6). Their morphologies and optical properties were characterized by TEM, fluorescence spectra and decay curves. A possible formation mechanism including burst-nucleation and growth process was proposed. The results reveal that when the pH increases from 1 to 2 to 4-6, the nanocrystals' mean size reduces slightly and the morphologies transform from the hollow sphere to the packed hexagon. The fluorescence lifetime and quantum efficiency achieved maximum for the samples synthesized at pH = 2. These nanocrystals with small size (<30 nm) and bright photoluminescence are promising phosphors in the applications of biological, optical amplifiers and liquid laser fields. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000372676500016
ISSN: 0254-0584
eISSN: 1879-3312
第 166 条,共 261 条
标题: Speed up deep neural network based pedestrian detection by sharing features across multi-scale models
作者: Jiang, XH (Jiang, Xiaoheng); Pang, YW (Pang, Yanwei); Li, XL (Li, Xuelong); Pan, J (Pan, Jing)
来源出版物: NEUROCOMPUTING 卷: 185 页: 163-170 DOI: 10.1016/j.neucom.2015.12.042 出版年: APR 12 2016
摘要: Deep neural networks (DNNs) have now demonstrated state-of-the-art detection performance on pedestrian datasets. However, because of their high computational complexity, detection efficiency is still a frustrating problem even with the help of Graphics Processing Units (GPUs). To improve detection efficiency, this paper proposes to share features across a group of DNNs that correspond to pedestrian models of different sizes. By sharing features, the computational burden for extracting features from an image pyramid can be significantly reduced. Simultaneously, we can detect pedestrians of several different scales on one single layer of an image pyramid. Furthermore, the improvement of detection efficiency is achieved with negligible loss of detection accuracy. Experimental results demonstrate the robustness and efficiency of the proposed algorithm. (C) 2015 The Authors. Published by Elsevier B.V.
入藏号: WOS:000374363900017
ISSN: 0925-2312
eISSN: 1872-8286
第 167 条,共 261 条
标题: Experimental demonstration of 3D accelerating beam arrays
作者: Yu, XH (Yu, Xianghua); Li, RZ (Li, Runze); Yan, SH (Yan, Shaohui); Yao, BL (Yao, Baoli); Gao, P (Gao, Peng); Han, GX (Han, Guoxia); Lei, M (Lei, Ming)
来源出版物: APPLIED OPTICS 卷: 55 期: 11 页: 3090-3095 DOI: 10.1364/AO.55.003090 出版年: APR 10 2016
摘要: Accelerating beams have attracted much attention in the frontiers of optical physics and technology owing to their unique propagation dynamics of nondiffracting, self-healing, and freely accelerating along curved trajectories. Such behaviors essentially arise from the particular phase factor occurring in their spatial frequency spectrum, e.g., the cubic phase associated to the spectrum of Airy beam. In this paper, we theoretically and experimentally demonstrate a sort of accelerating beam arrays, which are composed of spatially separated accelerating beams. By superimposing kinoforms of multifocal patterns into the spatial frequency spectrum of accelerating beams, different types of beam arrays, e.g., Airy beam arrays and two-main-lobe accelerating beam arrays, are generated and measured by scanning a reflection mirror near the focal region along the optical axis. The 3D intensity patterns reconstructed from the experimental data present good agreement with the theoretical counterparts. The combination of accelerating beams with optical beam arrays proposed here may find potential applications in various fields such as optical microscopes, optical micromachining, optical trapping, and so on. (C) 2016 Optical Society of America
入藏号: WOS:000373617000038
PubMed ID: 27139879
ISSN: 1559-128X
eISSN: 2155-3165
第 168 条,共 261 条
标题: Dynamics analysis of microsphere in a dual-beam fiber-optic trap with transverse offset
作者: Chen, XL (Chen, Xinlin); Xiao, GZ (Xiao, Guangzong); Luo, H (Luo, Hui); Xiong, W (Xiong, Wei); Yang, KY (Yang, Kaiyong)
来源出版物: OPTICS EXPRESS 卷: 24 期: 7 页: 7575-7584 DOI: 10.1364/OE.24.007575 出版年: APR 4 2016
摘要: A comprehensive dynamics analysis of microsphere has been presented in a dual-beam fiber-optic trap with transverse offset. As the offset distance between two counterpropagating beams increases, the motion type of the microsphere starts with capture, then spiral motion, then orbital rotation, and ends with escape. We analyze the transformation process and mechanism of the four motion types based on ray optics approximation. Dynamic simulations show that the existence of critical offset distances at which different motion types transform. The result is an important step toward explaining physical phenomena in a dual-beam fiberoptic trap with transverse offset, and is generally applicable to achieving controllable motions of microspheres in integrated systems, such as microfluidic systems and lab-on-a-chip systems. (C) 2016 Optical Society of America
入藏号: WOS:000373469100069
PubMed ID: 27137046
ISSN: 1094-4087
第 169 条,共 261 条
标题: Near Infrared Quantum Cutting of Tb3+-Yb3+ Co-Doped CeF3 Nanophosphors
作者: Sun, X (Sun Xiao); Hu, XY (Hu Xiao-Yun); Hou, WQ (Hou Wen-Qian); Fan, J (Fan Jun); Miao, H (Miao Hui); Zhan, SC (Zhan Su-Chang)
来源出版物: JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 卷: 16 期: 4 页: 3577-3582 DOI: 10.1166/jnn.2016.11880 出版年: APR 2016
摘要: In this paper, Tb3+-Yb3+ Co-doped CeF3 nanophosphors were synthesized using the microwave-assisted heating hydrothermal method (M-H). The excitation and emission spectra of the samples at room temperature show that the samples absorb ultraviolet light from 250 nm to 280 nm, and emit light at 300 nm. This corresponds to the transitions from D-5 to F-4 of Ce3+, 480 nm, 540 nm, 583 nm, 620 nm which correspond to the transitions from D-5(4) to F-7(6),(5,4,3) of Tb3+, 973 nm which corresponds to the transitions from F-2(5/2)-F-2(7/2) of Yb3+. In the emission spectra, it is clear that the emission intensity of Ce3+ and Tb3+ decreases, and Yb3+ increases with increasing Yb3+. This suggests that energy transfer from Ce3+ to Yb3+, and Ce3+ to Tb3+ to Yb3+ may occur. In the near infrared emission area, it is noted that a distinct emission centered at 973 nm was observed under 260 nm excitation. This is due to transitions among the different Stark levels of F-2(J(J=5/2, 7/2)) Yb3+ ions. This also suggests an energy transfer from Ce3+ ions to Tb3+ and then to Yb3+. The energy transfers from Tb3+-Yb3+ Co-doped CeF3 nanophosphors, which lead to intense NIR emissions at 900-1050 nm, match the energy of Si band gaps of Si-based solar cells. Therefore, these kinds of materials are promising candidates for applications that require modifying if solar spectrums and enhancement of conversion efficiency of Si-based solar cells.
入藏号: WOS:000386122700072
PubMed ID: 27451668
作者识别号:
作者        ResearcherID 号        ORCID 号
Fan, Jun         I-9469-2017         
ISSN: 1533-4880
eISSN: 1533-4899
第 170 条,共 261 条
标题: Aging behavior of large area MCP-PMT
作者: Wang, WW (Wang, Wen-Wen); Qian, S (Qian, Sen); Qi, M (Qi, Ming); Xia, JK (Xia, Jing-Kai); Cheng, YP (Cheng, Ya-Ping); Ning, Z (Ning, Zhe); Heng, YK (Heng, Yue-Kun); Liu, SL (Liu, Shu-Lin); Si, SG (Si, Shu-Guang); Sun, JN (Sun, Jian-Ning); Li, D (Li, Dong); Wang, XC (Wang, Xing-Chao); Huang, GR (Huang, Guo-Rui); Tian, JS (Tian, Jing-Shou); Wei, YL (Wei, Yong-Lin); Liu, HL (Liu, Hu-Lin); Li, WH (Li, Wei-Hua); Wang, X (Wang, Xing); Xin, LW (Xin, Li-Wei)
来源出版物: NUCLEAR SCIENCE AND TECHNIQUES 卷: 27 期: 2 文献号: 38 DOI: 10.1007/s41365-016-0046-1 出版年: APR 2016
摘要: The Institute of High Energy Physics, Chinese Academy of Sciences have designed a new type of photomultiplier tube (PMT) based on microchannel plates (MCPs) with large area photocathode, known as large area microchannel plate photomultiplier tube (MCP-PMT). The aging characteristics of the large area MCP-PMTs are different from dynode PMTs and small proximity-focus MCP-PMT. In this work, a prototype large area MCP-PMT was aged by operating with nearly 1000 photoelectrons per pulse for 3 months, and aging process of the MCP-PMT was discussed based on the aging curve.
入藏号: WOS:000376333000021
ISSN: 1001-8042
eISSN: 2210-3147
第 171 条,共 261 条
标题: Generation of cylindrical vector beams based on common-path interferometer with a vortex phase plate
作者: Liang, YS (Liang, Yansheng); Yan, SH (Yan, Shaohui); Yao, BL (Yao, Baoli); Lei, M (Lei, Ming); Min, JW (Min, Junwei); Yu, XH (Yu, Xianghua)
来源出版物: OPTICAL ENGINEERING 卷: 55 期: 4 文献号: 046117 DOI: 10.1117/1.OE.55.4.046117 出版年: APR 2016
摘要: Cylindrical vector (CV) beams have found increasing applications in physics, biology, and chemistry. To generate CV beams, interferometric technique is popularly adopted due to its flexibility. However, most interferometric configurations for the generation of CV beams are faced with system instability arising from external disturbance, limiting their practical applications. A common-path interferometer for the generation of radially and azimuthally polarized beams is proposed to improve the system stability. The optical configuration consists of a vortex phase plate acting to tailor the phase profile and a cube nonpolarizing beamsplitter to split the input beam into two components with mirror-like spiral phase distribution. The generated CV beams show a high quality in polarization and exhibit a better stability of beam profile than those obtained by noncommon-path interferometric configurations. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000375950900037
ISSN: 0091-3286
eISSN: 1560-2303
第 172 条,共 261 条
标题: Compressed sensing sparse reconstruction for coherent field imaging
作者: Cao, B (Cao, Bei); Luo, XJ (Luo, Xiu-Juan); Zhang, Y (Zhang, Yu); Liu, H (Liu, Hui); Chen, ML (Chen, Ming-Lai)
来源出版物: CHINESE PHYSICS B 卷: 25 期: 4 文献号: 040701 DOI: 10.1088/1674-1056/25/4/040701 出版年: APR 2016
摘要: Return signal processing and reconstruction plays a pivotal role in coherent field imaging, having a significant influence on the quality of the reconstructed image. To reduce the required samples and accelerate the sampling process, we propose a genuine sparse reconstruction scheme based on compressed sensing theory. By analyzing the sparsity of the received signal in the Fourier spectrum domain, we accomplish an effective random projection and then reconstruct the return signal from as little as 10% of traditional samples, finally acquiring the target image precisely. The results of the numerical simulations and practical experiments verify the correctness of the proposed method, providing an efficient processing approach for imaging fast-moving targets in the future.
入藏号: WOS:000375662600012
ISSN: 1674-1056
eISSN: 1741-4199
第 173 条,共 261 条
标题: Planar waveguides in neodymium-doped calcium niobium gallium garnet crystals produced by proton implantation
作者: Liu, CX (Liu, Chun-Xiao); Chen, M (Chen, Meng); Fu, LL (Fu, Li-Li); Zheng, RL (Zheng, Rui-Lin); Guo, HT (Guo, Hai-Tao); Zhou, ZG (Zhou, Zhi-Guang); Li, WN (Li, Wei-Nan); Lin, SB (Lin, She-Bao); Wei, W (Wei, Wei)
来源出版物: CHINESE PHYSICS B 卷: 25 期: 4 文献号: 044211 DOI: 10.1088/1674-1056/25/4/044211 出版年: APR 2016
摘要: In this work, the fabrication and optical properties of a planar waveguide in a neodymium-doped calcium niobium gallium garnet (Nd:CNGG) crystal are reported. The waveguide is produced by proton (H+) implantation at 480 keV and a fluence of 1.0 x 10(17) ions/cm(2). The prism-coupling measurement is performed to obtain the dark mode of the waveguide at a wavelength of 632.8 nm. The reflectivity calculation method (RCM) is used to reconstruct the refractive index profile. The finite- difference beam propagation method (FD-BPM) is employed to calculate the guided mode profile of the waveguide. The stopping and range of ions in matter 2010 (SRIM 2010) code is used to simulate the damage profile induced by the ion implantation. The experimental and theoretical results indicate that the waveguide can confine the light propagation.
入藏号: WOS:000375662600029
ISSN: 1674-1056
eISSN: 1741-4199
第 174 条,共 261 条
标题: Experiment Research and Analysis of Spectral Prediction on Soil Leaking Oil Content
作者: Yu, L (Yu Lu); Liu, XB (Liu Xue-bin); Liu, GZ (Liu Gui-zhong); Feng, YT (Feng Yu-tao); Wang, S (Wang Shuang); Yu, T (Yu Tao)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 36 期: 4 页: 1116-1120 DOI: 10.3964/j.issn.1000-0593(2016)04-1116-05 出版年: APR 2016
摘要: The spectral analysis method was applied experimentally to extract the spectral indices, measure and analyze the spectral characteristics and their difference of the mixture which are composed in soil in Central Shaanxi Plain and the diesel and motor oil respectively, aiming to provide solutions to practical difficulties in detecting, analyzing the spectral characteristics and difference between the soil leaking with equal content diesel and motor oil and predicting the leaking content of diesel in the soil. The spectral response curves of the soil leaking with different oil respectively and the soil leaking with diesel with different content were collected. Then the spectral prediction model for the leaking content of diesel in the soil was built based on the reflectance characteristics. The coefficient of the detection (R-2) was introduced to evaluate the stability of the built model, and the parameter root mean squared error (RMSE) was introduced to estimate the precision and the predictability of the model built in this work. It is demonstrated that : (1) The reflectance of soil leaking with diesel is less than that of the equal content motor oil. And there is a double absorption trough of the reflectance curve of both soil leaking with diesel and motor oil at 1 740 and 2 328 nm. The spectral absorption indices and absorption depth of the soil leaking with diesel keep less than the equal content motor oil. (2) The built spectral prediction model for the leaking content of diesel in the soil demonstrates good stability with the coefficient of determination at R-2 = 0. 854, and performs favorable predictability (Root-Mean-Square Error, RMSE=0.016), which can benefit the effective prediction and quick estimation methods of the leaking content of diesel in the soil, enrich and progress the experimental method and theoretical research work of spectral prediction on soil leaking oil content and promote the application of remote sensing in safety production and environmental protection.
入藏号: WOS:000374625000039
ISSN: 1000-0593
第 175 条,共 261 条
标题: A New Spectral-Spatial Algorithm Method for Hyperspectral Image Target Detection
作者: Wang, CL (Wang Cai-ling); Wang, HW (Wang Hong-wei); Hu, BL (Hu Bing-liang); Wen, J (Wen Jia); Xu, J (Xu Jun); Li, XJ (Li Xiang-juan)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 36 期: 4 页: 1163-1169 DOI: 10.3964/j.issn.1000-0593(2016)04-1163-07 出版年: APR 2016
摘要: With high-resolution spatial information and continuous spectrum information, hyperspectral remote sensing image has a unique advantage in the field of target detection. Traditional hyperspectral remote sensing image target detection methods emphasis on using spectral information to determine deterministic algorithm and statistical algorithms. Deterministic algorithms find the target by calculating the distance between the target spectrum and detected spectrum however, they are unable to detect sub-pixel target and are easily affected by noise. Statistical methods which calculate background statistical characteristics to detect abnormal point as target. It can detect subpixel target targets and small targets better thanbig size target,. With the spatial resolution increasing, subpixel target detection target has gradually grown to a single pixel and multi-pixel target. At this point, hyperspectral image usually has large homogeneous regions where the neighboring pixels wihin the regions consist of the same type of materials and have a similar spectral characteristics, therefore, the spatial information should be needed to incorporate into the algorithm for targe detection. This paper proposes an algorithm for hyperspectral target detection combined spectrum characteristics and spatial characteristics. The algorithm is based on traditional target detection operator and combined neighborhood clustering statistics. Firstly, the algorithm uses target detection operator to divided hyperspectral image into a potential target region and background region. Then, it calculates the centroid of the potential target area. Finally, as the centroid for neighborhood clustering center to dust data in order to exclud background from potential target area, through iterative calculation to obtain the final results of the target detection. The traditional statistics algorithms defines the total image as background area in order to extract background statistics features, and the algorithm propsed devided the total image into background part and potential target part, which cut off the target interference for background statistics feature extraction. Compared with CEM operators and ACE operators, the algorithm proposed outperforms than traditional operators in big target detection.
入藏号: WOS:000374625000047
ISSN: 1000-0593
第 176 条,共 261 条
标题: Analysis of the influence of nanofissure morphology on the performance of surface-conduction electron emitters
作者: Shen, ZH (Shen, Zhihua); Wang, X (Wang, Xiao); Wu, SL (Wu, Shengli); Tian, JS (Tian, JinShou)
来源出版物: JOURNAL OF MICROMECHANICS AND MICROENGINEERING 卷: 26 期: 4 文献号: 045011 DOI: 10.1088/0960-1317/26/4/045011 出版年: APR 2016
摘要: A simulation model was built to numerically investigate the electron emission property of a new surface-conduction electron emitter (SCE) with a raised emitter structure. The model calculated the electric field distribution, the electron emission characteristics, and the electron trajectories, which were useful for analyzing and understanding the microscopic mechanism of the electron emissions of the new SCE structure. It was found that the new structure increased the probability of electrons being collected by the anode which led to an increase of the anode current despite of the decrease of field emission current. This study benefits the advanced design of emitter structures in nanoscale technology for new types of electron sources.
入藏号: WOS:000375230900011
ISSN: 0960-1317
eISSN: 1361-6439
第 177 条,共 261 条
标题: Mutual Component Analysis for Heterogeneous Face Recognition
作者: Li, ZF (Li, Zhifeng); Gong, DH (Gong, Dihong); Li, Q (Li, Qiang); Tao, DC (Tao, Dacheng); Li, XL (Li, Xuelong)
来源出版物: ACM TRANSACTIONS ON INTELLIGENT SYSTEMS AND TECHNOLOGY 卷: 7 期: 3 特刊: SI 文献号: 28 DOI: 10.1145/2807705 出版年: APR 2016
摘要: Heterogeneous face recognition, also known as cross-modality face recognition or intermodality face recognition, refers to matching two face images from alternative image modalities. Since face images from different image modalities of the same person are associated with the same face object, there should be mutual components that reflect those intrinsic face characteristics that are invariant to the image modalities. Motivated by this rationality, we propose a novel approach called Mutual Component Analysis (MCA) to infer the mutual components for robust heterogeneous face recognition. In the MCA approach, a generative model is first proposed to model the process of generating face images in different modalities, and then an Expectation Maximization (EM) algorithm is designed to iteratively learn the model parameters. The learned generative model is able to infer the mutual components (which we call the hidden factor, where hidden means the factor is unreachable and invisible, and can only be inferred from observations) that are associated with the person's identity, thus enabling fast and effective matching for cross-modality face recognition. To enhance recognition performance, we propose an MCA-based multiclassifier framework using multiple local features. Experimental results show that our new approach significantly outperforms the state-of-the-art results on two typical application scenarios: sketch-to-photo and infrared-to-visible face recognition.
入藏号: WOS:000373911200003
ISSN: 2157-6904
eISSN: 2157-6912
第 178 条,共 261 条
标题: Fundamental-frequency-absorbed oxyfluoride glass in a high-power laser
作者: Hou, CQ (Hou, Chaoqi); Li, WN (Li, Weinan); Wang, PF (Wang, Pengfei); Lu, M (Lu, Min); Peng, B (Peng, Bo); Guo, HT (Guo, Haitao); Gao, F (Gao, Fei); Cui, XX (Cui, Xiaoxia)
来源出版物: APPLIED OPTICS 卷: 55 期: 10 页: 2649-2652 DOI: 10.1364/AO.55.002649 出版年: APR 1 2016
摘要: A high-power third-harmonic laser faces challenges in the filtering remnant unconverted fundamental frequency, which is from the frequency converting crystal. In this work, a novel fundamental-frequency-absorbed oxyfluoride glass has been prepared, which provides a possible option to solve the problem. By being doped with Fe2+ ion, the glass shows strong absorption property at 1053 nm, and the glass's transmittances at 351 and 1053 nm are stable with changing the laser power or increasing the irradiation times under high-power laser irradiation. Meanwhile, the laser-induced damage threshold of the glass is 12.5 J/cm(2) at 351 nm, which is two times higher than that of fused silica whose threshold is 6.2 J/cm(2) in the same testing condition. The glass also exhibits a higher laser-induced damage threshold as well as 36.6 J/cm(2) at its absorption wavelength of 1053 nm. The results indicate that this glass is promising as a color-separation optic, thus allowing a novel design for the final optics assembly in an inertial confinement fusion laser system. (C) 2016 Optical Society of America
入藏号: WOS:000373400800025
PubMed ID: 27139668
ISSN: 1559-128X
eISSN: 2155-3165
第 179 条,共 261 条
标题: Ytterbium-doped double-cladding fiber with 3.5 kW output power, fabricated by chelate gas phase deposition technique
作者: Hou, CQ (Hou, Chaoqi); Zhu, YG (Zhu, Yonggang); Zheng, JK (Zheng, Jinkun); Li, G (Li, Gang); Li, C (Li, Chao); Gao, S (Gao, Song); Gao, Q (Gao, Qi); Zhang, LH (Zhang, Lihua); Chang, C (Chang, Chang); Zhao, W (Zhao, Wei); Li, WN (Li, Weinan); Zhao, BY (Zhao, Baoyin)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 6 期: 4 页: 979-985 DOI: 10.1364/OME.6.000979 出版年: APR 1 2016
摘要: A ytterbium-doped double-cladding fiber was successfully fabricated by a chelate gas phase deposited technique. The measurement results of dopant concentration distribution and refractive index of preform indicate that radial and longitudinal homogeneity could be controlled perfectly with this technique. The absorption coefficients of fiber are 0.39 dB/m at 915nm and 1.02 dB/m at 976nm respectively. Using this fiber as the laser amplifier stage, 3592W output power at 1080nm with 72.5% slope efficiency was obtained with end-pump technique, which is close to the test results of Nufern commercial fiber. The results demonstrate that the chelate gas phase deposition technique is a relatively promising technique for high quality gain fiber fabrication. (C) 2016 Optical Society of America
入藏号: WOS:000373599200002
ISSN: 2159-3930
第 180 条,共 261 条
标题: Efficient and Robust Learning for Sustainable and Reacquisition-Enabled Hand Tracking
作者: Aziz, MAA (Aziz, Muhammad Ali Abdul); Niu, JW (Niu, Jianwei); Zhao, XK (Zhao, Xiaoke); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 4 页: 945-958 DOI: 10.1109/TCYB.2015.2418275 出版年: APR 2016
摘要: The use of machine learning approaches for long-term hand tracking poses some major challenges such as attaining robustness to inconsistencies in lighting, scale and object appearances, background clutter, and total object occlusion/disappearance. To address these issues in this paper, we present a robust machine learning approach based on enhanced particle filter trackers. The inherent drawbacks associated with the particle filter approach, i.e., sample degeneration and sample impoverishment, are minimized by infusing the particle filter with the mean shift approach. Moreover, to instill our tracker with reacquisition ability, we propose a rotation invariant and efficient detection framework named beta histograms of oriented gradients. Our robust appearance model operates on the red, green, blue color histogram and our newly proposed rotation invariant noise compensated local binary patterns descriptor, which is a noise compensated, rotation invariant version of the local binary patterns descriptor. Through our experiments, we demonstrate that our proposed hand tracker performs favorably against state-of-the-art algorithms on numerous challenging video sequences of hand postures, and overcomes the largely unsolved problem of redetecting hands after they vanish and reappear into the frame.
入藏号: WOS:000372791200007
ISSN: 2168-2267
eISSN: 2168-2275
第 181 条,共 261 条
标题: Relevance and irrelevance graph based marginal Fisher analysis for image search reranking
作者: Ji, Z (Ji, Zhong); Pang, YW (Pang, Yanwei); Yuan, Y (Yuan, Yuan); Pan, J (Pan, Jing)
来源出版物: SIGNAL PROCESSING 卷: 121 页: 139-152 DOI: 10.1016/j.sigpro.2015.11.010 出版年: APR 2016
摘要: Learning-to-rank techniques have shown promising results in the domain of image ranking recently, where dimensionality reduction is a critical step to overcome the "curse of dimensionality". However, conventional dimensionality reduction approaches cannot guarantee the satisfying performance because the important ranking information is ignored. This paper presents a novel "Ranking Dimensionality Reduction" scheme specifically designed for learning-to-rank based image ranking, which aims at not only discovering the intrinsic structure of data but also keeping the ordinal information. Within this scheme, a new dimensionality reduction algorithm called Relevance Marginal Fisher Analysis (RMFA) is proposed. RMFA models the proposed pairwise constraints of relevance-link and irrelevance-link into the relevance graph and the irrelevance graph, and applies the graphs to build the objective function with the idea of Marginal Fisher Analysis (MFA). Further, a semi-supervised RMFA algorithm called Semi-RMFA is developed to offer a more general solution for the real-world application. Extensive experiments are carried on two popular, real-world image search reranking datasets. The promising results demonstrate the robustness and effectiveness of the proposed scheme and methods. (C) 2015 Elsevier B.V. All rights reserved.
入藏号: WOS:000369193600012
ISSN: 0165-1684
eISSN: 1879-2677
第 182 条,共 261 条
标题: Gradient Permittivity Meta-Structure model for Wide-field Super-resolution imaging with a sub-45 nm resolution
作者: Cao, S (Cao, Shun); Wang, TS (Wang, Taisheng); Xu, WB (Xu, Wenbin); Liu, H (Liu, Hua); Zhang, HX (Zhang, Hongxin); Hu, BL (Hu, Bingliang); Yu, WX (Yu, Weixing)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 23460 DOI: 10.1038/srep23460 出版年: MAR 21 2016
摘要: A gradient permittivity meta-structure (GPMS) model and its application in super-resolution imaging were proposed and discussed in this work. The proposed GPMS consists of alternate metallic and dielectric films with a gradient permittivity which can support surface plasmons (SPs) standing wave interference patterns with a super resolution. By employing the rigorous numerical FDTD simulation method, the GPMS was carefully simulated to find that the period of the SPs interference pattern is only 84 nm for a 532 nm incident light. Furthermore, the potential application of the GPMS for wide-field super-resolution imaging was also discussed and the simulation results show that an imaging resolution of sub-45 nm can be achieved based on the plasmonic structure illumination microscopic method, which means a 5.3-fold improvement on resolution has been achieved in comparison with conventional epifluorescence microscopy. Moreover, besides the super-resolution imaging application, the proposed GPMS model can also be applied for nanolithography and other areas where super resolution patterns are needed.
入藏号: WOS:000372447200001
PubMed ID: 26996323
作者识别号:
作者        ResearcherID 号        ORCID 号
Yu, Weixing         G-3658-2012         0000-0002-3216-526X
Cao, Shun                  0000-0002-9841-2411
ISSN: 2045-2322
第 183 条,共 261 条
标题: Preparation and characterization of self-cleaning and anti-reflection ZnO-SiO2 nanometric films
作者: Guo, ZL (Guo Zhao-Long); Zhao, HX (Zhao Hai-Xin); Zhao, W (Zhao Wei)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 6 文献号: 064206 DOI: 10.7498/aps.65.064206 出版年: MAR 20 2016
摘要: Unlike the general anti-reflection and self-cleaning film such as SiO2 and TiO2-SiO2, the ZnO-SiO2 nanometric film used as a substrate of excellent transparency in visible region and effective photo-catalytic self-cleaning under UV illumination is seldom studied in the application as a substrate; however, it has a lot of advantages including high transmittance and low refractivity. In this paper, a self-cleaning and anti-reflection ZnO-SiO2 nanometric film is successfully fabricated by using a sol-gel dip-coating method. The morphology, crystal structure, surface microstructure and light transmittance of the obtained products are characterized by techniques such as TEM, SAD, XRD, SEM, DTA and UV-vis. Photo-catalytic degradation of the methylene blue (MB) in aqueous solution is used as probe reaction to evaluate the photo-catalytic activity of ZnO-SiO2 nanometric film. The TEM images reveal that the as-prepared ZnO nanoparticles are spherical grains with diameters of 12-20 nm, the average grain diameter is about 14.51 nm. ZnO nanoparticles obtained are of hexagonal wurtzite structure revealed by XRD pattern and there exist no other diffraction peaks. Furthermore, the SAD results show that ZnO microstructurs have good crystallinity. In addition, the ZnO grain size is about 14.41 nm by using the Scherrer formula calculation, which is consistent with the TEM results by the Gauss simulation. The UV-vis spectra reveal that the ultraviolet characteristic absorption peak of ZnO-SiO2 composite films is located at 368 nm and 375 nm after annealing at different temperatures such as 300 degrees C and 450 degrees C, corresponding to the band gaps of 3.37 eV and 3.31 eV, respectively. It is highly consistent with that obtained from pure ZnO nanoparticles. Increasing the annealing temperature results in a lower refractive index and the increases of the porosity in of the ZnO-SiO2 composite films. It has a uniformly refractive index value about 1.23-1.25 and a high porosity value about 50.3%-54.7% when the annealing temperature is 450 degrees C. Experimental results show that the ZnO-SiO 2 composite film can enhance the light transmittance of the quartz substrate, due to its lower reflective index and higher porosity. Compared with the quartz substrate, the average optical transmission rate of the quartz glass coated with ZnO-SiO 2 composite films is increased by about 4.17% at 400-800 nm, which favors greatly anti-reflection characteristics in a wide spectrum range. Meanwhile, the ZnO-SiO2 composite films are found to be efficient for photo-catalytically degradation of methylene blue dye under UV illumination, which favors greatly the self-cleaning function.
入藏号: WOS:000380354000020
ISSN: 1000-3290
第 184 条,共 261 条
标题: Generation of multiphoton entangled quantum states by means of integrated frequency combs
作者: Reimer, C (Reimer, Christian); Kues, M (Kues, Michael); Roztocki, P (Roztocki, Piotr); Wetzel, B (Wetzel, Benjamin); Grazioso, F (Grazioso, Fabio); Little, BE (Little, Brent E.); Chu, ST (Chu, Sai T.); Johnston, T (Johnston, Tudor); Bromberg, Y (Bromberg, Yaron); Caspani, L (Caspani, Lucia); Moss, DJ (Moss, David J.); Morandotti, R (Morandotti, Roberto)
来源出版物: SCIENCE 卷: 351 期: 6278 页: 1176-1180 DOI: 10.1126/science.aad8532 出版年: MAR 11 2016
摘要: Complex optical photon states with entanglement shared among several modes are critical to improving our fundamental understanding of quantum mechanics and have applications for quantum information processing, imaging, and microscopy. We demonstrate that optical integrated Kerr frequency combs can be used to generate several bi- and multiphoton entangled qubits, with direct applications for quantum communication and computation. Our method is compatible with contemporary fiber and quantum memory infrastructures and with chip-scale semiconductor technology, enabling compact, low-cost, and scalable implementations. The exploitation of integrated Kerr frequency combs, with their ability to generate multiple, customizable, and complex quantum states, can provide a scalable, practical, and compact platform for quantum technologies.
入藏号: WOS:000386158400040
PubMed ID: 26965623
作者识别号:
作者        ResearcherID 号        ORCID 号
CHU, Sai Tak                  0000-0001-8263-8507
Caspani, Lucia                  0000-0003-2711-0448
Wetzel, Benjamin                  0000-0002-2691-0307
moss, david                  0000-0001-5195-1744
ISSN: 0036-8075
eISSN: 1095-9203
第 185 条,共 261 条
标题: Theoretical analysis of the electromagnetic field inside an anomalous-dispersion microresonator under synthetical pump
作者: Xu, X (Xu, Xin); Hu, XH (Hu, Xiaohong); Feng, Y (Feng, Ye); Liu, YS (Liu, Yuanshan); Zhang, W (Zhang, Wei); Yang, Z (Yang, Zhi); Zhao, W (Zhao, Wei); Wang, YS (Wang, Yishan)
来源出版物: CHINESE PHYSICS B 卷: 25 期: 3 文献号: 034208 DOI: 10.1088/1674-1056/25/3/034208 出版年: MAR 2016
摘要: We study the spatiotemporal evolution of the electromagnetic field inside a microresonator showing an anomalous dispersion at the pump wavelength by using the normalized Lugiato-Lefever equation. Unlike the traditional single continuous wave (CW) pumping, an additional pump source consisting of periodical pulse train with variable repetition rate is adopted. The influences of the microresonator properties and the pump parameters on the field evolution and the electromagnetic field profile are analyzed. The simulation results indicate that, in the anomalous dispersion regime, both increases of the input pulse amplitude and the repetition frequency can result in the field profiles consisting of multiple peaks. A series of equidistant pulses can also be obtained by increasing the CW pump power. In addition, we find that a large physical detuning between the pump laser carrier and the cavity resonance frequency also causes the splitting of the inside field.
入藏号: WOS:000375647400028
ISSN: 1674-1056
eISSN: 1741-4199
第 186 条,共 261 条
标题: Measuring Collectiveness via Refined Topological Similarity
作者: Li, XL (Li, Xuelong); Chen, ML (Chen, Mulin); Wang, Q (Wang, Qi)
来源出版物: ACM TRANSACTIONS ON MULTIMEDIA COMPUTING COMMUNICATIONS AND APPLICATIONS 卷: 12 期: 2 文献号: 34 DOI: 10.1145/2854000 出版年: MAR 2016
摘要: Crowd system has motivated a surge of interests in many areas of multimedia, as it contains plenty of information about crowd scenes. In crowd systems, individuals tend to exhibit collective behaviors, and the motion of all those individuals is called collective motion. As a comprehensive descriptor of collective motion, collectiveness has been proposed to reflect the degree of individuals moving as an entirety. Nevertheless, existing works mostly have limitations to correctly find the individuals of a crowd system and precisely capture the various relationships between individuals, both of which are essential to measure collectiveness. In this article, we propose a collectiveness-measuring method that is capable of quantifying collectiveness accurately. Our main contributions are threefold: (1) we compute relatively accurate collectiveness by making the tracked feature points represent the individuals more precisely with a point selection strategy; (2) we jointly investigate the spatial-temporal information of individuals and utilize it to characterize the topological relationship between individuals by manifold learning; (3) we propose a stability descriptor to deal with the irregular individuals, which influence the calculation of collectiveness. Intensive experiments on the simulated and real world datasets demonstrate that the proposed method is able to compute relatively accurate collectiveness and keep high consistency with human perception.
入藏号: WOS:000373906200008
ISSN: 1551-6857
eISSN: 1551-6865
第 187 条,共 261 条
标题: Research on an Equal Wavelength Spectrum Reconstruction Method of Interference Imaging Spectrometer
作者: Xie, PY (Xie Pei-yue); Yang, JF (Yang Jian-feng); Xue, B (Xue Bin); Lu, J (Lu Juan); He, YH (He Ying-hong); Li, T (Li Ting); Ma, XL (Ma Xiao-long)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 36 期: 3 页: 848-852 DOI: 10.3964/j.issn.1000-0593(2016)03-0848-05 出版年: MAR 2016
摘要: Interference imaging spectrometer is one of the most important equipments of Chang'E 1 satellite, which is applied to analysis the material composition and its distribution of the surface on the moon. At present, the spectral resolution of level 2B scientific data obtained by existing methods is 325 cm(-1). If we use the description way of wavelength resolution, various spectrum is different; the first band is 7.6 nm, the last band is 29 nm, which introduces two questions: (1) the spectral resolution description way mismatch with the way of ground spectral library used for calibration and comparison; (2) The signal-to-noise ratio of the spectra in the shortwave band is low due to the signal entering narrow band is little. This paper discussed the relationship between wavelength resolution and cut-off function based on the reconstruction model of CE-1 interference imaging spectrometer. It proposed an adjustable cut-off function changing with wavelength or wavelength resolution, while selected the appropriate Sinc function as apodization to realize the reconstruction of arbitrary specified wavelength resolution in the band coverage. Then we used this method to CE-1 on orbit OB data to get a spectral image of 29 nm wavelength resolution. Finally, by using the signal-to-noise ratio, principal component analysis and unsupervised classification method on the reconstruction results with 2 grade science data from ground application system for comparison, the results showed that: signal-to-noise ratio of the shortwave band increased about 4 times, and the average increased about 2.4 times, the classification based on the spectrum was consistent, and the quality of the data was greatly improved. So, EWSR method has the advantages that: (1) in the case of keeping spectral information steadiness, it can improve the signal-to-noise ratio of shortwave band spectrum though sacrificed part of spectral resolution; (2) it can achieve the spectral data reconstruction which can set arbitrary band position or specify any wavelength resolution within the band range.
入藏号: WOS:000372478000045
作者识别号:
作者        ResearcherID 号        ORCID 号
kiaie, fatemeh         I-6083-2016         
kiaie, robabeh         I-2157-2016         
ISSN: 1000-0593
第 188 条,共 261 条
标题: Dual-Clustering-Based Hyperspectral Band Selection by Contextual Analysis
作者: Yuan, Y (Yuan, Yuan); Lin, JZ (Lin, Jianzhe); Wang, Q (Wang, Qi)
来源出版物: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 卷: 54 期: 3 页: 1431-1445 DOI: 10.1109/TGRS.2015.2480866 出版年: MAR 2016
摘要: Hyperspectral image (HSI) involves vast quantities of information that can help with the image analysis. However, this information has sometimes been proved to be redundant, considering specific applications such as HSI classification and anomaly detection. To address this problem, hyperspectral band selection is viewed as an effective dimensionality reduction method that can remove the redundant components of HSI. Various HSI band selection methods have been proposed recently, and the clustering-based method is a traditional one. This agglomerative method has been considered simple and straightforward, while the performance is generally inferior to the state of the art. To tackle the inherent drawbacks of the clustering-based band selection method, a new framework concerning on dual clustering is proposed in this paper. The main contribution can be concluded as follows: 1) a novel descriptor that reveals the context of HSI efficiently; 2) a dual clustering method that includes the contextual information in the clustering process; 3) a new strategy that selects the cluster representatives jointly considering the mutual effects of each cluster. Experimental results on three real-world HSIs verify the noticeable accuracy of the proposed method, with regard to the HSI classification application. The main comparison has been conducted among several recent clustering-based band selection methods and constraint-based band selection methods, demonstrating the superiority of the technique that we present.
入藏号: WOS:000372369400016
ISSN: 0196-2892
eISSN: 1558-0644
第 189 条,共 261 条
标题: Image Categorization by Learning a Propagated Graphlet Path
作者: Zhang, LM (Zhang, Luming); Hong, RC (Hong, Richang); Gao, Y (Gao, Yue); Ji, RR (Ji, Rongrong); Dai, QH (Dai, Qionghai); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 27 期: 3 页: 674-685 DOI: 10.1109/TNNLS.2015.2444417 出版年: MAR 2016
摘要: Spatial pyramid matching is a standard architecture for categorical image retrieval. However, its performance is largely limited by the prespecified rectangular spatial regions when pooling local descriptors. In this paper, we propose to learn object-shaped and directional receptive fields for image categorization. In particular, different objects in an image are seamlessly constructed by superpixels, while the direction captures human gaze shifting path. By generating a number of superpixels in each image, we construct graphlets to describe different objects. They function as the object-shaped receptive fields for image comparison. Due to the huge number of graphlets in an image, a saliency-guided graphlet selection algorithm is proposed. A manifold embedding algorithm encodes graphlets with the semantics of training image tags. Then, we derive a manifold propagation to calculate the postembedding graphlets by leveraging visual saliency maps. The sequentially propagated graphlets constitute a path that mimics human gaze shifting. Finally, we use the learned graphlet path as receptive fields for local image descriptor pooling. The local descriptors from similar receptive fields of pairwise images more significantly contribute to the final image kernel. Thorough experiments demonstrate the advantage of our approach.
入藏号: WOS:000372022900014
PubMed ID: 26625422
ISSN: 2162-237X
eISSN: 2162-2388
第 190 条,共 261 条
标题: An Orthogonal Method for Measurement Matrix Optimization
作者: Pan, JF (Pan, Jinfeng); Qiu, YH (Qiu, Yuehong)
来源出版物: CIRCUITS SYSTEMS AND SIGNAL PROCESSING 卷: 35 期: 3 页: 837-849 DOI: 10.1007/s00034-015-0107-4 出版年: MAR 2016
摘要: Compressive sensing theory states that signals can be sampled at a much smaller rate than that required by the Nyquist sampling theorem, because the sampling of a signal in the former is performed as a relatively small number of its linear measurements. Thus, the design of a measurement matrix is important in compressive sensing framework. A random measurement matrix optimization method is proposed in this study based on the incoherence principle of compressive sensing, which requires the mutual coherence of information operator to be small. The columns with mutual coherence are orthogonalized iteratively to decrease the mutual coherence of the information operator. The orthogonalization is realized by replacing the columns with the orthogonal matrix of their QR factorization. An information operator with smaller mutual coherence is acquired after the optimization, leading to an improved measurement matrix in terms of its relationship with the information operator. Results of several experiments show that the improved measurement matrix can reduce its mutual coherence with dictionaries compared with the random measurement matrix. The signal reconstruction error also decreases when the optimized measurement matrix is utilized.
入藏号: WOS:000370819100006
ISSN: 0278-081X
eISSN: 1531-5878
第 191 条,共 261 条
标题: Compact Structure Hashing via Sparse and Similarity Preserving Embedding
作者: Ye, RZ (Ye, Renzhen); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 3 页: 718-729 DOI: 10.1109/TCYB.2015.2414299 出版年: MAR 2016
摘要: Over the past few years, fast approximate nearest neighbor (ANN) search is desirable or essential, e.g., in huge databases, and therefore many hashing-based ANN techniques have been presented to return the nearest neighbors of a given query from huge databases. Hashing-based ANN techniques have become popular due to its low memory cost and good computational complexity. Recently, most of hashing methods have realized the importance of the relationship of the data and exploited the different structure of data to improve retrieval performance. However, a limitation of the aforementioned methods is that the sparse reconstructive relationship of the data is neglected. In this case, few methods can find the discriminating power and own the local properties of the data for learning compact and effective hash codes. To take this crucial issue into account, this paper proposes a method named special structure-based hashing (SSBH). SSBH can preserve the underlying geometric information among the data, and exploit the prior information that there exists sparse reconstructive relationship of the data, for learning compact and effective hash codes. Upon extensive experimental results, SSBH is demonstrated to be more robust and more effective than state-of-the-art hashing methods.
入藏号: WOS:000370963500012
PubMed ID: 25910267
ISSN: 2168-2267
eISSN: 2168-2275
第 192 条,共 261 条
标题: Principal Component 2-D Long Short-Term Memory for Font Recognition on Single Chinese Characters
作者: Tao, DP (Tao, Dapeng); Lin, X (Lin, Xu); Jin, LW (Jin, Lianwen); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 3 页: 756-765 DOI: 10.1109/TCYB.2015.2414920 出版年: MAR 2016
摘要: Chinese character font recognition (CCFR) has received increasing attention as the intelligent applications based on optical character recognition becomes popular. However, traditional CCFR systems do not handle noisy data effectively. By analyzing in detail the basic strokes of Chinese characters, we propose that font recognition on a single Chinese character is a sequence classification problem, which can be effectively solved by recurrent neural networks. For robust CCFR, we integrate a principal component convolution layer with the 2-D long short-term memory (2DLSTM) and develop principal component 2DLSTM (PC-2DLSTM) algorithm. PC-2DLSTM considers two aspects: 1) the principal component layer convolution operation helps remove the noise and get a rational and complete font information and 2) simultaneously, 2DLSTM deals with the long-range contextual processing along scan directions that can contribute to capture the contrast between character trajectory and background. Experiments using the frequently used CCFR dataset suggest the effectiveness of PC-2DLSTM compared with other state-of-the-art font recognition methods.
入藏号: WOS:000370963500015
PubMed ID: 25838536
ISSN: 2168-2267
eISSN: 2168-2275
第 193 条,共 261 条
标题: Hydrothermal synthesis of MoS2 nanosheets films: Microstructure and formation mechanism research
作者: Miao, H (Miao, Hui); Hu, XY (Hu, Xiaoyun); Sun, Q (Sun, Qian); Hao, YY (Hao, Yuanyuan); Wu, H (Wu, Hao); Zhang, DK (Zhang, Dekai); Bai, JT (Bai, Jintao); Liu, EZ (Liu, Enzhou); Fan, J (Fan, Jun); Hou, X (Hou, Xun)
来源出版物: MATERIALS LETTERS 卷: 166 页: 121-124 DOI: 10.1016/j.matlet.2015.12.010 出版年: MAR 1 2016
摘要: MoS2 nanosheets films were successfully prepared by Ti foil assisted hydrothermal synthesis method (labeled as Ti-MoS2 nanosheets films). The downside and upside of the films showed different novel morphologies with nanosheets arranged regularly and flowerlike microspheres, respectively. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). X-ray diffraction patterns showed that the peaks along (002) planes made a wide shift from 14.2 degrees to 9.4 degrees compared to its standard position located at 14.2 degrees at the beginning of the hydrothermal process, then gradually returned back to its normal position with the hydrothermal treatment time going on. However, time was not the only element to influence the position of the main diffraction peaks, a relatively low hydrothermal treatment temperature could also lead to the diffraction peaks' shift. In addition, TEM images indicated that the nanosheets film with hydrothermal treatment time for 24 h had a good single-crystal structure. Otherwise, the formation mechanism was carefully discussed and a possible formation mechanism was proposed. (C) 2015 Elsevier B.V. All rights reserved.
入藏号: WOS:000369061100032
作者识别号:
作者        ResearcherID 号        ORCID 号
Liu, Enzhou         I-9412-2017         
Fan, Jun         I-9469-2017         
ISSN: 0167-577X
eISSN: 1873-4979
第 194 条,共 261 条
标题: Slow axis collimation lens with variable curvature radius for semiconductor laser bars
作者: Xiong, LL (Xiong, Ling-Ling); Cai, L (Cai, Lei); Zheng, YF (Zheng, Yan-Fang); Liu, H (Liu, Hui); Zhang, P (Zhang, Pu); Nie, ZQ (Nie, Zhi-Qiang); Liu, XS (Liu, Xing-Sheng)
来源出版物: OPTICS AND LASER TECHNOLOGY 卷: 77 页: 1-5 DOI: 10.1016/j.optlastec.2015.08.004 出版年: MAR 2016
摘要: Based on Snell's law and the constant phase in the front of optical field, a design method of the slow axis collimation lens with variable curvature radius is proposed for semiconductor laser bars. Variable radius of the collimator is designed by the transmission angle, and it is demonstrated that the collimator has good beam collimation ability by material with low refractive index. Resorting to the design thought of finite element method, the surface of the collimator has been divided, and it is feasible to be fabricated. This method is applied as an example in collimation of a 976 nm semiconductor laser bar. 6 mrad divergence angle of collimated beam at slow axis is realized by the designed collimation lens with refraction index of 1.51. (C) 2015 Published by Elsevier Ltd.
入藏号: WOS:000366792300001
ISSN: 0030-3992
eISSN: 1879-2545
第 195 条,共 261 条
标题: Effect of different parameters on machining of SiC/SiC composites via pico-second laser
作者: Li, WN (Li, Weinan); Zhang, RH (Zhang, Ruoheng); Liu, YS (Liu, Yongsheng); Wang, CH (Wang, Chunhui); Wang, J (Wang, Jing); Yang, XJ (Yang, Xiaojun); Cheng, LF (Cheng, Laifei)
来源出版物: APPLIED SURFACE SCIENCE 卷: 364 页: 378-387 DOI: 10.1016/j.apsusc.2015.12.089 出版年: FEB 28 2016
摘要: Pico-second laser plays an important role in modern machining technology, especially in machining high hardness materials. In this article, pico-second laser was utilized for irradiation on SiC/SiC composites, and effects of different processing parameters including the machining modes and laser power were discussed in detail. The results indicated that the machining modes and laser power had great effect on machining of SiC/SiC composites. Different types of surface morphology and structure were observed under helical line scanning and single ring line scanning, and the analysis of their formulation was discussed in detail. It was believed that the machining modes would be responsible to the different shapes of machining results at the same parameters. The processing power shall also influence the surface morphology and quality of machining results. In micro-hole drilling process, large amount of debris and fragments were observed within the micro-holes, and XPS analysis showed that there existed Si-O bonds and Si-C bonds, indicating that the oxidation during processing was incomplete. Other surface morphology, such as pores and pits were discussed as well. (C) 2015 Elsevier B.V. All rights reserved.
入藏号: WOS:000369957800050
ISSN: 0169-4332
eISSN: 1873-5584
第 196 条,共 261 条
标题: Noise-hidden signal recovery via stochastic resonance in the SOI waveguide resonator
作者: Sun, H (Sun, Heng); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu); Han, J (Han, Jing); Li, SP (Li, Shaopeng)
来源出版物: JOURNAL OF PHYSICS D-APPLIED PHYSICS 卷: 49 期: 4 文献号: 045107 DOI: 10.1088/0022-3727/49/4/045107 出版年: FEB 3 2016
摘要: We propose a method to recover weak pulse signals buried in noise via stochastic resonance (SR) based on optical bistability induced by the free-carrier dispersion effect in the siliconon- insulator (SOI) waveguide resonator. The bistable system threshold is determined by the resonator parameters including the waveguide length, mirror reflectivity, and the free-carrier lifetime. A signal with different power levels can be detected by changing the free-carrier lifetime using a reverse-biased p-i-n junction embedded in the SOI waveguide. The influence of the system parameters on the SR is quantitatively analyzed by calculating the cross-correlation coefficient between the input and output signals. A cross-correlation gain of 5.6 is obtained by optimizing the system parameters of the SOI waveguide resonator. The results show the potential of using this structure to reconstruct and extract weak signals in all-optical integrated systems.
入藏号: WOS:000368096500017
作者识别号:
作者        ResearcherID 号        ORCID 号
Liu, Hongjun         D-2541-2016         
ISSN: 0022-3727
eISSN: 1361-6463
第 197 条,共 261 条
标题: Detecting Densely Distributed Graph Patterns for Fine-Grained Image Categorization
作者: Zhang, LM (Zhang, Luming); Yang, Y (Yang, Yang); Wang, M (Wang, Meng); Hong, RC (Hong, Richang); Nie, LQ (Nie, Liqiang); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 2 页: 553-565 DOI: 10.1109/TIP.2015.2502147 出版年: FEB 2016
摘要: Fine-grained image categorization is a challenging task aiming at distinguishing objects belonging to the same basic-level category, e.g., leaf or mushroom. It is a useful technique that can be applied for species recognition, face verification, and so on. Most of the existing methods either have difficulties to detect discriminative object components automatically, or suffer from the limited amount of training data in each sub-category. To solve these problems, this paper proposes a new fine-grained image categorization model. The key is a dense graph mining algorithm that hierarchically localizes discriminative object parts in each image. More specifically, to mimic the human hierarchical perception mechanism, a superpixel pyramid is generated for each image. Thereby, graphlets from each layer are constructed to seamlessly capture object components. Intuitively, graphlets representative to each super-/sub-category is densely distributed in their feature space. Thus, a dense graph mining algorithm is developed to discover graphlets representative to each super-/sub-category. Finally, the discovered graphlets from pairwise images are integrated into an image kernel for fine-grained recognition. Theoretically, the learned kernel can generalize several state-of-the-art image kernels. Experiments on nine image sets demonstrate the advantage of our method. Moreover, the discovered graphlets from each sub-category accurately capture those tiny discriminative object components, e.g., bird claws, heads, and bodies.
入藏号: WOS:000383905800005
PubMed ID: 26595921
ISSN: 1057-7149
eISSN: 1941-0042
第 198 条,共 261 条
标题: Surveillance Video Synopsis via Scaling Down Objects
作者: Li, XL (Li, Xuelong); Wang, ZG (Wang, Zhigang); Lu, XQ (Lu, Xiaoqiang)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 2 页: 740-755 DOI: 10.1109/TIP.2015.2507942 出版年: FEB 2016
摘要: Video synopsis is an effective technique to provide a compact representation of the original video by removing spatiotemporal redundancies and by preserving the essential activities. Most current approaches for video synopsis will cause collisions among objects, especially when the video is condensed much. In this paper, we present an approach for video synopsis to reduce the collisions. Our approach first shifts active objects along the time axis to compact the original video. Then, the sizes of the objects are reduced when collisions occur. Meanwhile, the geometric centroids of the objects will be kept unchanged to preserve the location information. Our contributions are threefold. First, an approach is proposed to decrease collisions in the synopsis video through reducing the sizes of the objects. Second, an optimization framework is developed to indicate the optimal time position and the appropriate reduction coefficient for each object. Finally, some metrics are proposed, and several experiments are carried out to evaluate the proposed approach. The experiments have demonstrated that the synopsis video produced by our approach has much fewer collisions while the compression ratio is high.
入藏号: WOS:000383905800019
ISSN: 1057-7149
eISSN: 1941-0042
第 199 条,共 261 条
标题: Discriminative Transfer Subspace Learning via Low-Rank and Sparse Representation
作者: Xu, Y (Xu, Yong); Fang, XZ (Fang, Xiaozhao); Wu, J (Wu, Jian); Li, XL (Li, Xuelong); Zhang, D (Zhang, David)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 2 页: 850-863 DOI: 10.1109/TIP.2015.2510498 出版年: FEB 2016
摘要: In this paper, we address the problem of unsupervised domain transfer learning in which no labels are available in the target domain. We use a transformation matrix to transfer both the source and target data to a common subspace, where each target sample can be represented by a combination of source samples such that the samples from different domains can be well interlaced. In this way, the discrepancy of the source and target domains is reduced. By imposing joint low-rank and sparse constraints on the reconstruction coefficient matrix, the global and local structures of data can be preserved. To enlarge the margins between different classes as much as possible and provide more freedom to diminish the discrepancy, a flexible linear classifier (projection) is obtained by learning a non-negative label relaxation matrix that allows the strict binary label matrix to relax into a slack variable matrix. Our method can avoid a potentially negative transfer by using a sparse matrix to model the noise and, thus, is more robust to different types of noise. We formulate our problem as a constrained low-rankness and sparsity minimization problem and solve it by the inexact augmented Lagrange multiplier method. Extensive experiments on various visual domain adaptation tasks show the superiority of the proposed method over the state-of-the art methods. The MATLAB code of our method will be publicly available at http://www.yongxu.org/lunwen.html.
入藏号: WOS:000383905800028
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhang, David         O-9396-2016         0000-0002-5027-5286
ISSN: 1057-7149
eISSN: 1941-0042
第 200 条,共 261 条
标题: Quasi-All-Fiber High-Efficiency Divided Chirp-Pulse Amplification System Based on Active Controlling
作者: Yu, J (Yu, J.); Feng, Y (Feng, Y.); Duan, LN (Duan, L. N.); Li, XH (Li, X. H.); Hu, XH (Hu, X. H.); Zhang, T (Zhang, T.); Zhang, W (Zhang, W.); Wang, YS (Wang, Y. S.); Yang, Z (Yang, Z.); Zhao, W (Zhao, W.)
来源出版物: IEEE PHOTONICS JOURNAL 卷: 8 期: 1 文献号: 7100409 DOI: 10.1109/JPHOT.2016.2524201 出版年: FEB 2016
摘要: We present a new high-efficiency divided chirp-pulse amplification (DCPA) system based on an actively controlled quasi-all-fiber structure. As a proof-of-principle experiment, a two-channel amplification system composed of single-mode ytterbium doped fiber is constructed. The experimental results show that the degree of linear polarization of similar to 93% is maintained after recombination and the system efficiency is up to similar to 95%. In addition, the beam quality (M-2 factor) is around 1.2. Moreover, the system can operate stably for a long time without performance degradation. Compared with the traditional spatial DCPA, this system exhibits some advantages, such as improved spatial adjustment, high stability, compact size, and low cost. It is demonstrated that this work paves the way to design a quasi-all-fiber high-performance pulsed laser system.
入藏号: WOS:000375479300038
作者识别号:
作者        ResearcherID 号        ORCID 号
Jia, Yu         F-2165-2017         0000-0003-1737-7667
Li, Xiaohui         J-9580-2012         0000-0002-5600-3820
ISSN: 1943-0655
eISSN: 1943-0647

第 201 条,共 261 条
标题: Fuzzy bag of words for social image description
作者: Li, YS (Li, Yanshan); Liu, WM (Liu, Weiming); Huang, QH (Huang, Qinghua); Li, XL (Li, Xuelong)
来源出版物: MULTIMEDIA TOOLS AND APPLICATIONS 卷: 75 期: 3 页: 1371-1390 DOI: 10.1007/s11042-014-2138-4 出版年: FEB 2016
摘要: Rapid growth of social media resources brings huge challenges and opportunities for image description technologies. The performance of image description method directly affects the accuracy of image retrieval, image annotation and image recognition. Bag of Words (BoW) as an efficient approach to describing the images has been attracting more and more attention. However, in traditional BoW, the maps between the words in the codebook and the features extracted from the images are actually ambiguous. As the Fuzzy Sets Theory (FST) is a powerful means for dealing with uncertainty efficiently, we utilize the FST to solve the problem caused by the ambiguity between the features and words. Accordingly, we propose a new type of BoW named as FBoW to describe images based on FST. Firstly, the features are extracted from the images. Secondly, k-means is utilized to learn the codebook. Thirdly, a fuzzy membership function is designed to measure the similarity between the features and words. The optimal parameters of the fuzzy membership function are obtained by using a Genetic Algorithm (GA). The histogram is generated by adding up the fuzzy membership values of each word to describe the images. The experimental results show that the proposed FBoW outperforms traditional BoW for social image description.
入藏号: WOS:000371309600002
作者识别号:
作者        ResearcherID 号        ORCID 号
liu, Weiming                  0000-0003-3700-4307
ISSN: 1380-7501
eISSN: 1573-7721
第 202 条,共 261 条
标题: Optical waveguides fabricated by nitrogen ion implantation in fused silica
作者: Liu, CX (Liu, Chun-Xiao); Fu, LL (Fu, Li-Li); Zheng, RL (Zheng, Rui-Lin); Guo, HT (Guo, Hai-Tao); Zhou, ZG (Zhou, Zhi-Guang); Li, WN (Li, Wei-Nan); Lin, SB (Lin, She-Bao); Wei, W (Wei, Wei)
来源出版物: OPTICAL ENGINEERING 卷: 55 期: 2 文献号: 027105 DOI: 10.1117/1.OE.55.2.027105 出版年: FEB 2016
摘要: We report on the fabrication of waveguides in fused silica using 4.5-MeV nitrogen ion implantation with a fluence of 5.0 x 10(14) ions/cm(2). The prism-coupling method was employed to measure the effective refractive indices of guiding modes at the wavelengths of 632.8 and 1539 nm. The effective refractive indices of the first few modes were higher than that of the substrate. The refractive index profiles at 632.8 and 1539 nm were reconstructed by the reflectivity calculation method. Positive index changes were induced in the waveguide layers. The end-face coupling method was used to measure the near-field light intensity distributions at the wavelength of 632.8 nm and the finite-difference beam propagation method was applied to simulate the guided mode profile at the wavelength of 1539 nm. The waveguide structures emerge as candidates for integrated photonic devices. (C) 2016 Society of Photo- Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000371283600048
ISSN: 0091-3286
eISSN: 1560-2303
第 203 条,共 261 条
标题: A Local Structural Descriptor for Image Matching via Normalized Graph Laplacian Embedding
作者: Tang, J (Tang, Jun); Shao, L (Shao, Ling); Li, XL (Li, Xuelong); Lu, K (Lu, Ke)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 2 特刊: SI 页: 410-420 DOI: 10.1109/TCYB.2015.2402751 出版年: FEB 2016
摘要: This paper investigates graph spectral approaches to the problem of point pattern matching. Specifically, we concentrate on the issue of how to effectively use graph spectral properties to characterize point patterns in the presence of positional jitter and outliers. A novel local spectral descriptor is proposed to represent the attribute domain of feature points. For a point in a given point-set, weight graphs are constructed on its neighboring points and then their normalized Laplacian matrices are computed. According to the known spectral radius of the normalized Laplacian matrix, the distribution of the eigen-values of these normalized Laplacian matrices is summarized as a histogram to form a descriptor. The proposed spectral descriptor is finally combined with the approximate distance order for recovering correspondences between point-sets. Extensive experiments demonstrate the effectiveness of the proposed approach and its superiority to the existing methods.
入藏号: WOS:000370962900008
ISSN: 2168-2267
eISSN: 2168-2275
第 204 条,共 261 条
标题: Block-Row Sparse Multiview Multilabel Learning for Image Classification
作者: Zhu, XF (Zhu, Xiaofeng); Li, XL (Li, Xuelong); Zhang, SC (Zhang, Shichao)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 2 特刊: SI 页: 450-461 DOI: 10.1109/TCYB.2015.2403356 出版年: FEB 2016
摘要: In image analysis, the images are often represented by multiple visual features (also known as multiview features), that aim to better interpret them for achieving remarkable performance of the learning. Since the processes of feature extraction on each view are separated, the multiple visual features of images may include overlap, noise, and redundancy. Thus, learning with all the derived views of the data could decrease the effectiveness. To address this, this paper simultaneously conducts a hierarchical feature selection and a multiview multilabel (MVML) learning for multiview image classification, via embedding a proposed a new block-row regularizer into the MVML framework. The block-row regularizer concatenating a Frobenius norm (F-norm) regularizer and an l(2,1)-norm regularizer is designed to conduct a hierarchical feature selection, in which the F-norm regularizer is used to conduct a high-level feature selection for selecting the informative views (i.e., discarding the uninformative views) and the l(2,1)-norm regularizer is then used to conduct a low-level feature selection on the informative views. The rationale of the use of a block-row regularizer is to avoid the issue of the over-fitting (via the block-row regularizer), to remove redundant views and to preserve the natural group structures of data (via the F-norm regularizer), and to remove noisy features (the l(2,1)-norm regularizer), respectively. We further devise a computationally efficient algorithm to optimize the derived objective function and also theoretically prove the convergence of the proposed optimization method. Finally, the results on real image datasets show that the proposed method outperforms two baseline algorithms and three state-of-the-art algorithms in terms of classification performance.
入藏号: WOS:000370962900011
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhu, Xiaofeng         F-3601-2016         
ISSN: 2168-2267
eISSN: 2168-2275
第 205 条,共 261 条
标题: Two-Stage Learning to Predict Human Eye Fixations via SDAEs
作者: Han, JW (Han, Junwei); Zhang, DW (Zhang, Dingwen); Wen, SF (Wen, Shifeng); Guo, L (Guo, Lei); Liu, TM (Liu, Tianming); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 2 特刊: SI 页: 487-498 DOI: 10.1109/TCYB.2015.2404432 出版年: FEB 2016
摘要: Saliency detection models aiming to quantitatively predict human eye-attended locations in the visual field have been receiving increasing research interest in recent years. Unlike traditional methods that rely on hand-designed features and contrast inference mechanisms, this paper proposes a novel framework to learn saliency detection models from raw image data using deep networks. The proposed framework mainly consists of two learning stages. At the first learning stage, we develop a stacked denoising autoencoder (SDAE) model to learn robust, representative features from raw image data under an unsupervised manner. The second learning stage aims to jointly learn optimal mechanisms to capture the intrinsic mutual patterns as the feature contrast and to integrate them for final saliency prediction. Given the input of pairs of a center patch and its surrounding patches represented by the features learned at the first stage, a SDAE network is trained under the supervision of eye fixation labels, which achieves both contrast inference and contrast integration simultaneously. Experiments on three publically available eye tracking benchmarks and the comparisons with 16 state-of-the-art approaches demonstrate the effectiveness of the proposed framework.
入藏号: WOS:000370962900014
PubMed ID: 25730840
作者识别号:
作者        ResearcherID 号        ORCID 号
zhang, dingwen         S-9447-2017         0000-0001-8369-8886
ISSN: 2168-2267
eISSN: 2168-2275
第 206 条,共 261 条
标题: Large-Scale Aerial Image Categorization Using a Multitask Topological Codebook
作者: Zhang, LM (Zhang, Luming); Wang, M (Wang, Meng); Hong, RC (Hong, Richang); Yin, BC (Yin, Bao-Cai); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 2 特刊: SI 页: 535-545 DOI: 10.1109/TCYB.2015.2408592 出版年: FEB 2016
摘要: Fast and accurately categorizing the millions of aerial images on Google Maps is a useful technique in pattern recognition. Existing methods cannot handle this task successfully due to two reasons: 1) the aerial images' topologies are the key feature to distinguish their categories, but they cannot be effectively encoded by a conventional visual codebook and 2) it is challenging to build a realtime image categorization system, as some geo-aware Apps update over 20 aerial images per second. To solve these problems, we propose an efficient aerial image categorization algorithm. It focuses on learning a discriminative topological codebook of aerial images under a multitask learning framework. The pipeline can be summarized as follows. We first construct a region adjacency graph (RAG) that describes the topology of each aerial image. Naturally, aerial image categorization can be formulated as RAG-to-RAG matching. According to graph theory, RAG-to-RAG matching is conducted by enumeratively comparing all their respective graphlets (i.e., small subgraphs). To alleviate the high time consumption, we propose to learn a codebook containing topologies jointly discriminative to multiple categories. The learned topological codebook guides the extraction of the discriminative graphlets. Finally, these graphlets are integrated into an AdaBoost model for predicting aerial image categories. Experimental results show that our approach is competitive to several existing recognition models. Furthermore, over 24 aerial images are processed per second, demonstrating that our approach is ready for real-world applications.
入藏号: WOS:000370962900018
ISSN: 2168-2267
eISSN: 2168-2275
第 207 条,共 261 条
标题: Passively mode-locked erbium-doped fiber laser via a D-shape-fiber-based MoS2 saturable absorber with a very low nonsaturable loss
作者: Duan, LN (Duan, Li-Na); Su, YL (Su, Yu-Long); Wang, YG (Wang, Yong-Gang); Li, L (Li, Lu); Wang, X (Wang, Xi); Wang, YS (Wang, Yi-Shan)
来源出版物: CHINESE PHYSICS B 卷: 25 期: 2 文献号: 024206 DOI: 10.1088/1674-1056/25/2/024206 出版年: FEB 2016
摘要: We report on the generation of conventional and dissipative solitons in erbium-doped fiber lasers by the evanescent field interaction between the propagating light and a multilayer molybdenum disulfide (MoS2) thin film. The MoS2 film is fabricated by depositing the MoS2 water-ethanol mixture on a D-shape-fiber (DF) repetitively. The measured nonsaturable loss, saturable optical intensity, and the modulation depth of this device are 13.3%, 110 MW/cm(2), and 3.4% respectively. Owing to the very low nonsaturable loss, the laser threshold of conventional soliton is as low as 4.8 mW. The further increase of net cavity dispersion to normal regime, stable dissipation soliton pulse trains with a spectral bandwidth of 11.7 nm and pulse duration of 116 ps are successfully generated. Our experiment demonstrates that the MoS2-DF device can indeed be used as a high performance saturable absorber for further applications in ultrafast photonics.
入藏号: WOS:000370179100028
ISSN: 1674-1056
eISSN: 1741-4199
第 208 条,共 261 条
标题: Preparation method of Ce1-xZrxO2/tourmaline nanocomposite with high far-infrared emissivity and its mechanism
作者: Guo, B (Guo, Bin); Yang, LQ (Yang, Liqing); Li, WL (Li, Wenlong); Wang, HJ (Wang, Haojing); Zhang, H (Zhang, Hong)
来源出版物: APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 卷: 122 期: 2 文献号: 89 DOI: 10.1007/s00339-015-9586-1 出版年: FEB 2016
摘要: Far-infrared functional nanocomposites were prepared by the coprecipitation method using natural tourmaline (XY(3)Z(6)Si(6)O(18)(BO3)(3)V3W, where X is Na+, Ca2+, K+, or vacancy; Y is Mg2+, Fe2+, Mn2+, Al3+, Fe3+, Mn3+, Cr3+, Li+, or Ti4+; Z is Al3+, Mg2+, Cr3+, or V3+; V is O2-, OH-; and W is O2-, OH-, or F-) powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that Ce-Zr can further enhance the far-infrared emission properties of tourmaline than Ce alone. Through characterization by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), the mechanism by which Ce(-Zr) acts on the far-infrared emission property of tourmaline was systematically studied. The XPS spectra show that the Fe3+ ratio inside tourmaline powders after heat treatment can be raised by doping Ce and further raised after adding Zr. Moreover, it is showed that Ce3+ is dominant inside the samples, but its dominance is replaced by Ce4+ outside. In addition, XRD results indicate the formation of CeO2 and Ce(1-x)ZrxO(2) crystallites during the heat treatment, and further, TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce-Zr-doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of Fe2+ (0.074 nm in radius) to Fe3+ (0.064 nm in radius) inside the tourmaline caused by Zr enhancing the redox shift between Ce4+ and Ce3+ via improving the oxygen mobility in the Ce-Zr crystal.
入藏号: WOS:000369972400044
ISSN: 0947-8396
eISSN: 1432-0630
第 209 条,共 261 条
标题: Carbon-implanted monomode waveguides in magneto-optical glasses for waveguide isolators
作者: Liu, CX (Liu, Chun-Xiao); Fu, LL (Fu, Li-Li); Zhang, LL (Zhang, Liao-Lin); Guo, HT (Guo, Hai-Tao); Li, WN (Li, Wei-Nan); Lin, SB (Lin, She-Bao); Wei, W (Wei, Wei)
来源出版物: APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 卷: 122 期: 2 文献号: 94 DOI: 10.1007/s00339-016-9631-8 出版年: FEB 2016
摘要: Tb3+-doped aluminum borosilicate glasses are important magneto-optical materials for optical isolators. Optical waveguides are basic components in integrated photonics. By using the ion implantation technique, optical guiding structures can be produced in Tb3+-doped aluminum borosilicate glasses, and miniaturized waveguide isolators can be realized. In this paper, planar waveguides have been fabricated in Tb3+-doped aluminum borosilicate glasses by (6.0 + 5.5) MeV carbon ion implantation at doses of (8.0 + 4.0) 9 10 13 ions/cm(2). The optical properties of optical waveguides are measured by equipments of prism coupling and end-face coupling systems. They are also analyzed by simulation programs of intensity calculation method and beam propagation method. The waveguides with good optical performances suggest potential applications on fabrication of waveguide isolators in Tb3+-doped aluminum borosilicate glasses.
入藏号: WOS:000369972400049
ISSN: 0947-8396
eISSN: 1432-0630
第 210 条,共 261 条
标题: Query-Adaptive Reciprocal Hash Tables for Nearest Neighbor Search
作者: Liu, XL (Liu, Xianglong); Deng, C (Deng, Cheng); Lang, B (Lang, Bo); Tao, DC (Tao, Dacheng); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 2 页: 907-919 DOI: 10.1109/TIP.2015.2505180 出版年: FEB 2016
摘要: Recent years have witnessed the success of binary hashing techniques in approximate nearest neighbor search. In practice, multiple hash tables are usually built using hashing to cover more desired results in the hit buckets of each table. However, rare work studies the unified approach to constructing multiple informative hash tables using any type of hashing algorithms. Meanwhile, for multiple table search, it also lacks of a generic query-adaptive and fine-grained ranking scheme that can alleviate the binary quantization loss suffered in the standard hashing techniques. To solve the above problems, in this paper, we first regard the table construction as a selection problem over a set of candidate hash functions. With the graph representation of the function set, we propose an efficient solution that sequentially applies normalized dominant set to finding the most informative and independent hash functions for each table. To further reduce the redundancy between tables, we explore the reciprocal hash tables in a boosting manner, where the hash function graph is updated with high weights emphasized on the misclassified neighbor pairs of previous hash tables. To refine the ranking of the retrieved buckets within a certain Hamming radius from the query, we propose a query-adaptive bitwise weighting scheme to enable fine-grained bucket ranking in each hash table, exploiting the discriminative power of its hash functions and their complement for nearest neighbor search. Moreover, we integrate such scheme into the multiple table search using a fast, yet reciprocal table lookup algorithm within the adaptive weighted Hamming radius. In this paper, both the construction method and the query-adaptive search method are general and compatible with different types of hashing algorithms using different feature spaces and/or parameter settings. Our extensive experiments on several large-scale benchmarks demonstrate that the proposed techniques can significantly outperform both the naive construction methods and the state-of-the-art hashing algorithms.
入藏号: WOS:000368938400003
ISSN: 1057-7149
eISSN: 1941-0042
第 211 条,共 261 条
标题: Material research on the InGaAs-emitting-layer VECSEL grown on GaAs substrate
作者: Lin, T (Lin, Tao); Sun, RJ (Sun, Ruijuan); Sun, H (Sun, Hang); Guo, EM (Guo, Enmin); Duan, YP (Duan, Yupeng); Lin, N (Lin, Nan); Ma, XY (Ma, Xiaoyu); Wang, YG (Wang, Yonggang)
来源出版物: MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING 卷: 42 页: 283-287 DOI: 10.1016/j.mssp.2015.11.002 子辑: 3 出版年: FEB 2016
摘要: Wafers of InGaAs-emitting-layer vertical external cavity surface emitting semiconductor laser (VECSEL) gain chip and separate active region were grown on semi-insulator GaAs substrates by low pressure metal-organic vapor phase epitaxy (MOVPE). Photoluminescence (PL) wavelength of the active region could be adjusted linearly about 1 nm for increasing 1 sccm H-2 flow rate through TMIn under AsH3 flow rates of 150 sccm. The complicated surface-emitted PL signal of the VECSEL gain chip was strongly modulated by interferences within the multilayer and was interpreted by the aberrance of the quantum wells emission with a profile filtered by a micro-cavity resonance in the longitudinal confinement factor. Material tests of the VECSEL wafer showed the reflectivity of the DBR mirrors was in good agreement with the active region photoluminescence, and the wafer was obtained with high crystal quality. (C) 2015 Elsevier Ltd. All rights reserved.
入藏号: WOS:000367638400002
ISSN: 1369-8001
eISSN: 1873-4081
第 212 条,共 261 条
标题: Gain guided and index alternate-guided fibers designed for large-mode-area and single-mode laser with higher output power and slope efficiency
作者: Shen, X (Shen, Xiao); Wei, W (Wei, Wei)
来源出版物: OPTICS EXPRESS 卷: 24 期: 2 页: 1089-1095 DOI: 10.1364/OE.24.001089 出版年: JAN 25 2016
摘要: A gain guided and index alternate-guided fiber (GGIA-GF) is proposed and numerically demonstrated. The conditions of single mode oscillation are analyzed based on the fiber laser parameters. The output laser power and slope efficiency of the GGIA-GF laser are derived from the improved rate equations. The results show that the output characteristics of the laser based on GGIA-GF can be greatly improved than that of the gain guided and index anti-guided fiber laser through the optimal design of the fiber laser parameters. GGIA-GF would be better applied in the field of large mode area and single mode fiber lasers. (C) 2016 Optical Society of America
入藏号: WOS:000369066300076
PubMed ID: 26832493
ISSN: 1094-4087
第 213 条,共 261 条
标题: Active waveguides by low-fluence carbon implantation in Nd3+-doped fluorophosphate glasses
作者: Liu, CX (Liu, Chun-Xiao); Luo, ZY (Luo, Zhe-Yuan); Li, YW (Li, Yu-Wen); Chen, M (Chen, Meng); Xu, J (Xu, Jun); Fu, LL (Fu, Li-Li); Yu, KH (Yu, Ke-Han); Zheng, RL (Zheng, Rui-Lin); Zhou, ZG (Zhou, Zhi-Guang); Li, WN (Li, Wei-Nan); Guo, HT (Guo, Hai-Tao); Lin, SB (Lin, She-Bao); Wei, W (Wei, Wei)
来源出版物: MODERN PHYSICS LETTERS B 卷: 30 期: 2 文献号: 1550266 DOI: 10.1142/S0217984915502668 出版年: JAN 20 2016
摘要: A planar waveguide in the Nd3+-doped fluorophosphate glass is fabricated by a 6.0 MeV C3+ ion implantation at a low-fluence of 1.0 x 10(14) ions/cm(2). The fluence is close to that in semiconductor industry. The dark mode spectra are recorded by a model 2010 prism coupler. The energy losses during the implantation process and the refractive index profile of the waveguide are simulated by the SRIM 2010 code and the reflectivity calculation method (RCM), respectively. The near-field light intensity profile and the propagation loss of the waveguide are measured by an end-face coupling system. The two-dimensional (2D) modal profile of transverse electric (TE) mode for the fabricated waveguide is calculated by the finite difference beam propagation method (FD-BPM). The results of micro luminescence and optical absorption reveal that the spectroscopic characteristics of the Nd3+-doped fluorophosphate glass are nearly unaffected by the carbon ion implantation process. This work suggests that the carbon-implanted Nd3+-doped fluorophosphate glass waveguide is a promising candidate for integrated active devices.
入藏号: WOS:000371066800001
ISSN: 0217-9849
eISSN: 1793-6640
第 214 条,共 261 条
标题: Influence of absorption on stability of terahertz difference frequency generation
作者: Huang, N (Huang, Nan); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Wang, ZL (Wang, Zhaolu); Li, SP (Li, Shaopeng); Han, J (Han, Jing)
来源出版物: APPLIED OPTICS 卷: 55 期: 3 页: 444-448 DOI: 10.1364/AO.55.000444 出版年: JAN 20 2016
摘要: This work presents numerical studies of the stability feature of terahertz difference frequency generation (THz-DFG) with a ZnGeP2 crystal using two pump wavelengths. We found that the maximum output of a THz wave is located in the unstable output region because of the competitive equilibrium between the absorption and the gain. Furthermore, the output stability is dependent on the pump stability. Different from the results at the pump wavelength of 9.588 mu m, there is neither an appropriate stable output region nor gain saturation region at the pump wavelength of 1.064 mu m for a larger absorption coefficient. This work demonstrates that the stable output region of the THz wave is difficult to obtain when the pump absorption is excessively large in DFG. (C) 2016 Optical Society of America
入藏号: WOS:000369055100028
PubMed ID: 26835915
会议名称: OSA Topical Meeting on Digital Holography and 3D Imaging (DH)
会议日期: MAY, 2015
会议地点: Shanghai, PEOPLES R CHINA
作者识别号:
作者        ResearcherID 号        ORCID 号
Liu, Hongjun         D-2541-2016         
ISSN: 1559-128X
eISSN: 2155-3165
第 215 条,共 261 条
标题: Optical spectrum evolution induced by altering input light wavelength spacing
作者: Wang, MJ (Wang, Minjie); Ma, CW (Ma, Caiwen)
来源出版物: MODERN PHYSICS LETTERS B 卷: 30 期: 1 文献号: 1550259 DOI: 10.1142/S0217984915502590 出版年: JAN 10 2016
摘要: This study explored the optical spectrum evolution process using a pump-modulated light and a continuous-wave probe, launched simultaneously into a 1 km highly nonlinear fiber. A total of 70 optical spectra were obtained by each changing the wavelength spacing (0.4 nm) between the probe and pump lights. Simulation results indicated that wavelength spacing between the two beams caused a cyclical optical spectrum evolution process induced by cross-phase modulation. As input light wavelength spacing increased, the coupling between the two optical fields showed obvious attenuation in each neat, multi-peak cycle.
入藏号: WOS:000369095200006
ISSN: 0217-9849
eISSN: 1793-6640
第 216 条,共 261 条
标题: Optically induced rotation of Rayleigh particles by vortex beams with different states of polarization
作者: Li, MM (Li, Manman); Yan, SH (Yan, Shaohui); Yao, BL (Yao, Baoli); Liang, YS (Liang, Yansheng); Lei, M (Lei, Ming); Yang, YL (Yang, Yanlong)
来源出版物: PHYSICS LETTERS A 卷: 380 期: 1-2 页: 311-315 DOI: 10.1016/j.physleta.2015.08.026 出版年: JAN 8 2016
摘要: Optical vortex beams carry optical orbital angular momentum (OAM) and can induce an orbital motion of trapped particles in optical trapping. We show that the state of polarization (SOP) of vortex beams will affect the details of this optically induced orbital motion to some extent. Numerical results demonstrate that focusing the vortex beams with circular, radial or azimuthal polarizations can induce a uniform orbital motion on a trapped Rayleigh particle, while in the focal field of the vortex beam with linear polarization the particle experiences a non-uniform orbital motion. Among the formers, the vortex beam with circular polarization induces a maximum optical torque on the particle. Furthermore, by varying the topological charge of the vortex beams, the vortex beam with circular polarization gives rise to an optimum torque superior to those given by the other three vortex beams. These facts suggest that the circularly polarized vortex beam is more suitable for rotating particles. (C) 2015 Elsevier B.V. All rights reserved.
入藏号: WOS:000365365300051
ISSN: 0375-9601
eISSN: 1873-2429
第 217 条,共 261 条
标题: Synthesized computational aesthetic evaluation of photos
作者: Wang, WN (Wang, Weining); Cai, D (Cai, Dong); Wang, L (Wang, Li); Huang, QH (Huang, Qinghua); Xu, XM (Xu, Xiangmin); Li, XL (Li, Xuelong)
来源出版物: NEUROCOMPUTING 卷: 172 特刊: SI 页: 244-252 DOI: 10.1016/j.neucom.2014.12.106 出版年: JAN 8 2016
摘要: Assessing aesthetic appeal of images is a highly subjective task which has attracted a lot of interests recently. It is an interdisciplinary subject related to art, psychology, and computer vision. In this paper, we systematically study prior researches of feature extraction in this area, and category them into four groups, low level, rule based, information theory, and visual attention. In each group, the effectiveness and limitations of existing features are examined. Based on the analysis, we propose a comprehensive feature set, which include 16 novel features and 70 well proved features. With this feature set, we build the system under machine learning scheme consisting of an SVM based classifier to estimate if an image is high aesthetic or low aesthetic. The experiments are conducted on public datasets show that our comprehensive feature set outperforms conventional models that concentrate mainly on certain types of features. The combination of our features produces a promising classification accuracy of 82.4% and a good performance comparable to aesthetic rating of human. Finally, we implemented the proposed evaluation system on mobile devices. It can provide real-time feedback to help users capture appealing photos. (C) 2015 Elsevier B.V. All rights reserved.
入藏号: WOS:000364884700025
ISSN: 0925-2312
eISSN: 1872-8286
第 218 条,共 261 条
标题: Evolutionary mechanism of the defects in the fluoride-containing phosphate based glasses induced by gamma radiation
作者: Wang, PF (Wang, Pengfei); He, QL (He, Quanlong); Lu, M (Lu, Min); Li, WN (Li, Weinan); Peng, B (Peng, Bo)
来源出版物: SCIENTIFIC REPORTS 卷: 6 文献号: 18926 DOI: 10.1038/srep18926 出版年: JAN 6 2016
摘要: In the laser driven inertial confinement fusion (ICF) experimental target chamber, like the 3 omega (351 nm) laser irradiation, the irradiation of gamma ray and X-rays, will also cause the formation and increase of various defects in the investigated series of fluoride-containing phosphate based glasses that have potential use in novel high performance color separation optics. The induced defects contribute to the increase of absorption in the UV region, which will make the UV performance of these laser glasses deteriorated. Some of the induced defects can be bleached to some extent through the subsequent thermal treatment process, resulting from the release and capture of the electrons in conduction band. Through the gamma radiation and post-heat treatment experiments, a general model of the evolutionary mechanism of the defects in these fluoride-containing phosphate based glasses was proposed.
入藏号: WOS:000368094000001
PubMed ID: 26732043
ISSN: 2045-2322
第 219 条,共 261 条
标题: Dynamic properties of a small-size streak tube
作者: Hui, DD (Hui Dan-Dan); Tian, JS (Tian Jin-Shou); Wang, JF (Wang Jun-Feng); Lu, Y (Lu Yu); Wen, WL (Wen Wen-Long); Xu, XY (Xu Xiang-Yan)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 1 文献号: 018502 DOI: 10.7498/aps.65.018502 出版年: JAN 5 2016
摘要: Scannerless (flash) lidar system based on streak camera is able to realize three-dimensional (3D) multi-spectral fluorescence imaging and 3D imaging polarimetry. Compared with conventional lidar system, the flash lidar system overcomes image distortions caused by the motion between the target and the sensor platform. Other advantages of the flash lidar system are higher image update rates and the potential for creating a miniaturized lidar system. To meet the requirements for developing this new technology, a super small-sized, large photocathode area and meshless streak tube with spherical cathode and screen is designed with the aid of computer simulation technology (CST) software. The tube with nearly 28 mm wide photocathode work area contains two electrostatic focusing lens, a pair of deflection plates, and a 50 mm diameter output screen. The external dimension of the tube is merely 50 mm x 100 mm. And its electromagnetic fields are calculated in the CST Particle Studio based on the finite integration theory. Some dynamic properties of the tube are analyzed via observing different electron trajectories launched from a number of different points on the cathode. The influences of the deflector position on deflection sensitivity and spatial resolution are analyzed. Increasing the distance between the deflector and the anode pin hole leads to a worse deflection sensitivity but a better spatial resolution. As for the temporal resolution, three electron pulses separated by 30 ps can be well resolved by the streak tube in the dynamic mode. Thus, the dynamic temporal resolution of the streak tube is better than 30 ps. And a 10 lp/mm spatial resolution across the 28 mm long slit on the photocathode can be obtained by estimating modulation transfer functions of the electron trajectories. Temporal distortions at the entire photocathode working area are evaluated, and the data reveal that the larger the photocathode working area, the bigger the temporal distortions are. Also, the temporal distortion is present mainly in the photocathode-to-deflection plates region. In addition, the slit image of the streak tube working in the dynamic mode is simulated and presented. The phenomenon that the slit image is curved due to the temporal distortion is analyzed. Two rectangular electron pulses separated by 50 ps are well resolved by the streak tube. Therefore, the temporal resolution of this small-size steak tube is better than 50 ps with a rectangular slit dimension of 30 mm x 50 mu m on the photocathode, and its electron-optic magnification is 1.2.
入藏号: WOS:000370940200046
ISSN: 1000-3290
第 220 条,共 261 条
标题: X-ray focusing optics and its application in X-ray communication system
作者: Liu, D (Liu Duo); Qiang, PF (Qiang Peng-Fei); Li, LS (Li Lin-Sen); Su, T (Su Tong); Sheng, LZ (Sheng Li-Zhi); Liu, YA (Liu Yong-An); Zhao, BS (Zhao Bao-Sheng)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 1 文献号: 010703 DOI: 10.7498/aps.65.010703 出版年: JAN 5 2016
摘要: X-ray communication, which was first introduced by Keith Gendreau in 2007, is potential to compete with conventional communication methods, such as microware and laser communication, against space surroundings. Researchers have spent much time and effort on the mission making the initial idea into reality in recent years. Eventually, the X-ray communication demonstration system based on the grid-controlled X-ray source and single-photon detection technique can deliver both audio and video information in a 6-meter vacuum tunnel, and the bit-error-rate performance of the communication system is analyzed. But it is difficult to implement applications in industries. The point is to find a way to reduce the signal divergence geometrical attenuation and increase the distance of the communication which can be regarded as an important foundation of future deep-space X-ray communication applications. Therefore, it is urgent to study the X-ray communication system. By using a nested X-ray focusing optics as transmitting and receiving antennas of the communication system, the signal gain and the distance of X-ray communication can be greatly improved. Specifically, the nested X-ray focusing optics is similar to the Wolter type I telescope, which is widely used in the field of X-ray astronomy. The difference between them is that the Wolter type I optics is originally proposed based on a paraboloid mirror and a hyperboloid mirror, but X-ray focusing optics, the simplified Wolter type I optics, provides a single reflection by a conical approximation mirror, and it is more suitable for X-ray communication. In this paper, aiming at the future demand of X-ray communication, the optimization and analysis of the nested X-ray focusing optics are carried out, and the recurrence relations between the layers of mirrors are derived. Reasonable initial structural parameters and structure of the optics are designed. In addition, the theoretical effective collection area is calculated. Feasibility of using the X-ray focusing optics as transmitting and receiving antennas is analyzed, and the theory and structural design of the X-ray focusing optical are discussed. Signal divergence of transmitting antenna, effective area of receiving antenna, the focal spot size, and the signal gain properties are preliminary studied. The results show that the signal divergence is about 3 mrad, and the transmit gain is 23 dB; the effective area of receiving antenna is 5700 mm 2 at 1.5 keV. Moreover, the focal spot diameter and the receive gain are 4.5 mm and 25 dB, respectively, and the total gain of this communication system can reach up to 48 dB.
入藏号: WOS:000370940200005
ISSN: 1000-3290
第 221 条,共 261 条
标题: Experimental study on three-dimensional ptychography for thick sample
作者: Pan, A (Pan An); Zhang, XF (Zhang Xiao-Fei); Wang, B (Wang Bin); Zhao, Q (Zhao Qing); Shi, YS (Shi Yi-Shi)
来源出版物: ACTA PHYSICA SINICA 卷: 65 期: 1 文献号: 014204 DOI: 10.7498/aps.65.014204 出版年: JAN 5 2016
摘要: Ptychography is a new kind of lens-less imaging technology. What restricts the technique is the assumption of a multiplicative interaction between the illuminating coherent beam and the specimen, and the ptychography cannot be applied to samples thicker than a few tens of micrometers in the case of visible-light imaging at micron-scale resolution. In the present work, we split a sample into axial sections, thereby realize three-dimensional ptychographic imaging of thick samples at the millimeter level in a series of computer simulations and optical experiments. Our simulation results reveal that by using single wavelength we cannot achieve good-quality images of thick samples. Thus it is necessary to introduce more wavelengths for illumination. With increasing the number of wavelengths, the imaging quality of three-dimensional thick samples can be enhanced continually. Then we make further study on the relationship between the imaging quality and the magnitude of wavelength in optical experiments by using two groups of samples with different thickness values. The results demonstrate that our experimental results are highly consistent with simulations. For our concrete configuration in this paper, the best results of imaging and separation may be obtained for the case of tri-wavelength. At the same time we make a reasonable explanation for the phenomenon of fold-over in the experiment. Our results are important and meaningful for the practical utilizing of three-dimensional ptychography of thick samples.
入藏号: WOS:000370940200011
ISSN: 1000-3290
第 222 条,共 261 条
标题: Selective Level Set Segmentation Using Fuzzy Region Competition
作者: Li, BN (Li, Bing Nan); Qin, J (Qin, Jing); Wang, R (Wang, Rong); Wang, M (Wang, Meng); Li, XL (Li, Xuelong)
来源出版物: IEEE ACCESS 卷: 4 页: 4777-4788 DOI: 10.1109/ACCESS.2016.2590440 出版年: 2016
摘要: Deformable models and level set methods have been extensively investigated for computerized image segmentation. However, medical image segmentation is yet one of open challenges owing to diversified physiology, pathology, and imaging modalities. Existing level set methods suffer from some inherent drawbacks in face of noise, ambiguity, and inhomogeneity. It is also refractory to control level set segmentation that is dependent on image content and evolutional strategies. In this paper, a new level set formulation is proposed by using fuzzy region competition for selective image segmentation. It is able to detect and track the arbitrary combination of selected objects or image components. To the best of our knowledge, this new formulation should be one of the first proposals in a framework of region competition for selective segmentation. Experiments on both synthetic and real images validate its advantages in selective level set segmentation.
入藏号: WOS:000397826600001
作者识别号:
作者        ResearcherID 号        ORCID 号
LI, Bing Nan         E-7575-2010         0000-0002-4777-5773
ISSN: 2169-3536
第 223 条,共 261 条
标题: Effects of Gamma Radiation and Heat Treatment on the Photoluminescence of the Fluoride-Containing Phosphate-Based Glasses
作者: He, QL (He, Quanlong); Wang, PF (Wang, Pengfei); Lu, M (Lu, Min); Peng, B (Peng, Bo)
来源出版物: ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY 卷: 5 期: 10 页: R192-R197 DOI: 10.1149/2.0041612jss 出版年: 2016
摘要: We demonstrate, for the first time to our knowledge, two different balances around fluorine-related non-paramagnetic color (FD) centers in fluoride containing phosphate based optical filter glasses at low (190 degrees C) and higher (390 degrees C) heat-treatment temperature, respectively. The thermal bleaching experiment results indicate the heat-treatment bleached gamma radiation induced phosphate-related oxygen hole center (POHC) and oxygen-related hole center (OHC) to some extent due to the release and capture of the electrons in the conduction band. Through the gamma radiation and subsequent heat-treatment experiment, as well as the detailed analysis of photoluminescence and excitation spectra, a general model corresponding to the two different balances about the FD defects and the evolutionary mechanism of these existing defects in the fluoride-containing phosphate based glasses was proposed. (C) 2016 The Electrochemical Society. All rights reserved.
入藏号: WOS:000388868500035
ISSN: 2162-8769
第 224 条,共 261 条
标题: The Effects of Femtosecond Laser Processing on the Surface Accuracy of Fibre Laser Clad Sidewalls
作者: Li, R (Li, R.); Yang, XJ (Yang, X-J.); Zhao, W (Zhao, W.); He, B (He, B.); Zhao, HL (Zhao, H-L.); Zhu, WY (Zhu, W-Y.)
来源出版物: LASERS IN ENGINEERING 卷: 35 期: 5-6 页: 239-247 出版年: 2016
摘要: To enhance the surface accuracy of laser metal direct forming pieces, a method applying femtosecond laser to fabricate the cladding sidewalls is proposed in this paper. The effects of laser fluence, scanning speed and scanning strategy on the processing accuracy are studied systematically. The experimental results show that when the laser fluence increases, the roughness of cladding sidewalls also increases. The roughness of the cladding sidewall is decreased firstly and then increased with the increasing scanning speed. When the laser fluence is between 0.12 and 0.34 J/cm(2), the roughness of cladding sidewall is less than 3 mu m. What is more, under single scanning strategy the sidewalls roughness is less than that when back and forth scanning method is used.
入藏号: WOS:000389757300001
ISSN: 0898-1507
eISSN: 1029-029X
第 225 条,共 261 条
标题: Pulse duration tunable fiber CPA system based on thermally dispersion tuning of chirped fiber bragg grating
作者: Zhang, X (Zhang Xin); Yang, Z (Yang Zhi); Li, QL (Li Qianglong); Li, F (Li Feng); Yang, XJ (Yang Xiaojun); Wang, YS (Wang Yishan); Zhao, W (Zhao Wei)
来源出版物: OPTIK 卷: 127 期: 20 页: 8728-8731 DOI: 10.1016/j.ijleo.2016.06.062 出版年: 2016
摘要: A pulse width tunable fiber-based chirp pulse amplification (CPA) system had been built by our newly developed dispersion tuning mechanism. In order to realize dispersion fine tuning, we changed the temperature of chirped fiber Bragg grating (CFBG), which was used as stretcher in CPA system, to change the dispersion compensation level between stretcher and grating pairs compressor. By the help of this method, the minimum pulse width after compression can be obtained by balancing the dispersion of the stretcher and of the compressor. In our experimental fiber CPA system, the minimum pulse duration of 780 fs was recorded by autocorrelator during the CFBG temperature tuning at temperature range of 0 degrees C to 50 degrees C, and the pulse tuning accuracy can reach about 3 fs/degrees C. (C) 2016 Elsevier GmbH. All rights reserved.
入藏号: WOS:000389102500071
ISSN: 0030-4026
第 226 条,共 261 条
标题: Inverse sinusoidal phase mask to extend the depth of field of incoherent imaging systems
作者: Zhou, L (Zhou, Liang); Liu, ZH (Liu, Zhaohui); She, WJ (She, Wenji); Shan, QS (Shan, Qiusha)
来源出版物: OPTIK 卷: 127 期: 20 页: 9105-9110 DOI: 10.1016/j.ijleo.2016.06.131 出版年: 2016
摘要: Wavefront coding is an effective way to extend the depth of field of an incoherent imaging system. With a suitable phase mask, the defocus invariant imaging characteristic of an incoherent imaging system can be achieved. In this paper, an effective way to generate new type of phase mask is proposed. On the basis of the new method, the inverse sinusoidal phase mask is proposed to enrich the family of anti-symmetric phase masks. The performances of inverse sinusoidal phase mask are evaluated by comparisons with cubic, sinusoidal and tangent phase masks. Numerical evaluations demonstrate that the proposed phase mask has superior performance in extending the depth of field and small artifacts in restored images, particularly at large defocus. (C) 2016 Elsevier GmbH. All rights reserved.
入藏号: WOS:000389102500118
ISSN: 0030-4026
第 227 条,共 261 条
标题: Influence of electrode types on the electrohydrodynamic instability patterning process: a comparative study
作者: Liu, MZ (Liu, Minzhe); Li, HF (Li, Hefu); Yu, WX (Yu, Weixing); Wang, TS (Wang, Taisheng); Liu, ZY (Liu, Zhenyu); Desmulliez, MPY (Desmulliez, Marc. P. Y.)
来源出版物: RSC Advances 卷: 6 期: 113 页: 112300-112306 DOI: 10.1039/c6ra05596f 出版年: 2016
摘要: This article studies the effect that different types of patterned electrodes have on the electrohydrodynamic instability patterning (EHDIP) process for the faithful replication of micro-and nanostructures. Two types of patterned electrodes are studied. One is fully conductive, i.e. both pattern and substrate are conductive. The other type has conductive microstructures fabricated on a dielectric substrate. By employing the COMSOL (TM) Multiphysics software package, a rigorous numerical simulation of the EHDIP process has been carried out for both types of electrodes. The simulation results show that both electrodes can realize a faithful replication of the micro-and nanostructures once the variable, Delta E/Delta x, reaches the critical value. Moreover, it is demonstrated that a fully conductive template is preferred if a small polymer film thickness is employed; a partially conductive electrode is preferred for larger film thickness. These results provide guidelines for the better control of the EHDIP process in order to realize the perfect pattern replication of structures for a variety of applications in MEMS or micro/nanofluidics.
入藏号: WOS:000389708700075
作者识别号:
作者        ResearcherID 号        ORCID 号
Liu, Zhenyu         E-9551-2010         
Desmulliez, Marc                  0000-0002-2441-1598
ISSN: 2046-2069
第 228 条,共 261 条
标题: A non-negative low-rank representation for hyperspectral band selection
作者: Feng, YC (Feng, Yachuang); Yuan, Y (Yuan, Yuan); Lu, XQ (Lu, Xiaoqiang)
来源出版物: INTERNATIONAL JOURNAL OF REMOTE SENSING 卷: 37 期: 19 页: 4590-4609 DOI: 10.1080/01431161.2016.1214299 出版年: 2016
摘要: Hyperspectral images are widely used in real applications due to their rich spectral information. However, the large volume brings a lot of inconvenience, such as storage and transmission. Hyperspectral band selection is an important technique to cope with this issue by selecting a few spectral bands to replace the original image. This article proposes a novel band selection algorithm that first estimates the redundancy through analysing relationships among spectral bands. After that, spectral bands are ranked according to their relative importance. Subsequently, in order to remove redundant spectral bands and preserve the original information, a maximal linearly independent subset is constructed as the optimal band combination. Contributions of this article are listed as follows: (1) A new strategy for band selection is proposed to preserve the original information mostly; (2) A non-negative low-rank representation algorithm is developed to discover intrinsic relationships among spectral bands; (3) A smart strategy is put forward to adaptively determine the optimal combination of spectral bands. To verify the effectiveness, experiments have been conducted on both hyperspectral unmixing and classification. For unmixing, the proposed algorithm decreases the average root mean square errors (RMSEs) by 0.05, 0.03, and 0.05 for the Urban, Cuprite, and Indian Pines data sets, respectively. With regard to classification, our algorithm achieves the overall accuracies of 77.07% and 89.19% for the Indian Pines and Pavia University data sets, respectively. These results are close to the performance with original images. Thus, comparative experiments not only illustrate the superiority of the proposed algorithm, but also prove the validity of band selection on hyperspectral image processing.
入藏号: WOS:000383576800005
ISSN: 0143-1161
eISSN: 1366-5901
第 229 条,共 261 条
标题: Deep Learning for Hyperspectral Data Classification through Exponential Momentum Deep Convolution Neural Networks
作者: Yue, Q (Yue, Qi); Ma, CW (Ma, Caiwen)
来源出版物: JOURNAL OF SENSORS 文献号: 3150632 DOI: 10.1155/2016/3150632 出版年: 2016
摘要: Classification is a hot topic in hyperspectral remote sensing community. In the last decades, numerous efforts have been concentrated on the classification problem. Most of the existing studies and research efforts are following the conventional pattern recognition paradigm, which is based on complex handcrafted features. However, it is rarely known which features are important for the problem. In this paper, a new classification skeleton based on deep machine learning is proposed for hyperspectral data. The proposed classification framework, which is composed of exponential momentum deep convolution neural network and support vector machine (SVM), can hierarchically construct high-level spectral-spatial features in an automated way. Experimental results and quantitative validation on widely used datasets showcase the potential of the developed approach for accurate hyperspectral data classification.
入藏号: WOS:000387381100001
ISSN: 1687-725X
eISSN: 1687-7268
第 230 条,共 261 条
标题: High-precision algorithm of surface parameter of parabolic primary mirror for space solar telescope
作者: Xu, GZ (Xu, Guangzhou); Ruan, P (Ruan, Ping); Yang, JF (Yang, Jianfeng); Li, F (Li, Fu); Yan, XT (Yan, Xingtao); Wang, S (Wang, Sen)
来源出版物: OPTIK 卷: 127 期: 22 页: 10687-10696 DOI: 10.1016/j.ijleo.2016.08.066 出版年: 2016
摘要: The parabolic primary mirror (PM) of space solar telescope is sensitive to the serious external loads and surface variation of PM has large influence on the optical performance of the telescope. To evaluate the PM change under the external loads accurately, the high precision algorithm based on the comprehensive surface parameter is presented. The discrete error of finite element discretization of optical surface is concerned for the first time and the elimination of discrete error is discussed as well. The calculation method of surface parameter including rigid body displacement, surface focus and root mean square is researched. Based on the high-precision algorithm, the surface parameter of PM under the isothermal temperature change is calculated and the law curve of surface parameter is also obtained with the change of temperature. The significant simulation result of surface parameter can effectively evaluate the surface change and guide the structure and environmental adaptation design of the PM. (C) 2016 Elsevier GmbH. All rights reserved.
入藏号: WOS:000385596100053
ISSN: 0030-4026
第 231 条,共 261 条
标题: Recent Advances in Cloud Radio Access Networks: System Architectures, Key Techniques, and Open Issues
作者: Peng, MG (Peng, Mugen); Sun, YH (Sun, Yaohua); Li, XL (Li, Xuelong); Mao, ZD (Mao, Zhendong); Wang, CG (Wang, Chonggang)
来源出版物: IEEE COMMUNICATIONS SURVEYS AND TUTORIALS 卷: 18 期: 3 页: 2282-2308 DOI: 10.1109/COMST.2016.2548658 出版年: 2016
摘要: As a promising paradigm to reduce both capital and operating expenditures, the cloud radio access network (C-RAN) has been shown to provide high spectral efficiency and energy efficiency. Motivated by its significant theoretical performance gains and potential advantages, C-RANs have been advocated by both the industry and research community. This paper comprehensively surveys the recent advances of C-RANs, including system architectures, key techniques, and open issues. The system architectures with different functional splits and the corresponding characteristics are comprehensively summarized and discussed. The state-of-the-art key techniques in C-RANs are classified as: the fronthaul compression, large-scale collaborative processing, and channel estimation in the physical layer; and the radio resource allocation and optimization in the upper layer. Additionally, given the extensiveness of the research area, open issues, and challenges are presented to spur future investigations, in which the involvement of edge cache, big data mining, social-aware device-to-device, cognitive radio, software defined network, and physical layer security for C-RANs are discussed, and the progress of testbed development and trial test is introduced as well.
入藏号: WOS:000384887100028
ISSN: 1553-877X
第 232 条,共 261 条
标题: WS2/fluorine mica (FM) saturable absorber for high power optical pulse formation
作者: Li, L (Li, L.); Wang, ZF (Wang, Z. F.); Wang, YG (Wang, Y. G.); Wang, X (Wang, X.); Yang, GW (Yang, G. W.)
来源出版物: OPTIK 卷: 127 期: 21 页: 10223-10227 DOI: 10.1016/j.ijleo.2016.08.040 出版年: 2016
摘要: The report presents the high power mode-locking operation in an anomalous-dispersion fiber laser with a novel WS2 saturable absorber (SA) based on fluorine mica (FM) substrate. Compared to organic host material such as polymer, FM has higher softening temperature, heat dissipation and laser damage threshold. By employing the SA, a stable mode-locked fiber laser is achieved. The duration of the pulse broadens from 2.816 ns to 3.654 ns almost linearly with increasing pump power. The average output power and single pulse energy can increase up to 33.5 mW and 4 nj at the maximum pump power respectively. The results indicate that WS2/FM material is an ideal SA for high power Er-doped fiber (EDF) lasers. (C) 2016 Elsevier GmbH. All rights reserved.
入藏号: WOS:000383522400012
ISSN: 0030-4026
第 233 条,共 261 条
标题: Intra-hour cloud movement detection for solar forecasts based on ground imaging system
作者: Jiang, BT (Jiang, Baotan); Pan, ZB (Pan, Zhibin); Qiu, YH (Qiu, Yuehong); Chen, Z (Chen, Zhi); Yao, DL (Yao, Dalei); Bu, F (Bu, Fan)
来源出版物: OPTIK 卷: 127 期: 19 页: 7803-7808 DOI: 10.1016/j.ijleo.2016.05.126 出版年: 2016
摘要: The penetration of solar energy continues to rise and becomes a central piece of the global energy mix. Thus, considering ways for more efficiently operated power systems to accommodate significant amounts of such a variable resource will be increasingly important. Improvements in solar forecasting methods and techniques will clearly be relevant. In addition to season and irradiation angle, the most important factor of influencing solar energy output is the effect of cloud movement on solar irradiation shadow on solar plate. This paper briefly analyzes the advantages and disadvantages of various moving target algorithms, and compares the typical feature matching algorithm (block motion estimation algorithm) and optical flow algorithm (CLG algorithm) against the collected cloud movement image sequence. The result shows that optical flow algorithm (CLG algorithm) is applied to cloud movement image. The calculation is very fast, with an accuracy above 96%. A comparison with CLG algorithm shows that direction and speed accuracy of block motion estimation algorithm based on hexagonal search pattern is 0.79 and 0.47, respectively. (C) 2016 Elsevier GmbH. All rights reserved.
入藏号: WOS:000380417900050
ISSN: 0030-4026
第 234 条,共 261 条
标题: Regularized Taylor Echo State Networks for Predictive Control of Partially Observed Systems
作者: Xiang, K (Xiang, Kui); Li, BN (Li, Bing Nan); Zhang, LY (Zhang, Liyan); Pang, MY (Pang, Muye); Wang, M (Wang, Meng); Li, XL (Li, Xuelong)
来源出版物: IEEE ACCESS 卷: 4 页: 3300-3309 DOI: 10.1109/ACCESS.2016.2582478 出版年: 2016
摘要: The existing neural networks suffer from partial observation while modeling and controlling dynamic systems. In this paper, a new linearized recurrent neural network, the Taylor expanded echo state network (TESN), is proposed for predictive control of partially observed dynamic systems. Two schemes of regularization, ridge regression and sparse regression, are imposed on TESNs to tackle the issue of ill-conditioned estimation. Furthermore, two estimators, lasso and elastic net, are investigated for sparse regression. Regularized learning is found to improve the estimation consistency of readout coefficients and, at the same time, suppress the accumulation of linearization residues in a prediction horizon. A series of experiments was carried out, and the results verified that regularized learning is contributive to TESNs in predictive control of partially observed dynamic systems.
入藏号: WOS:000380337900002
作者识别号:
作者        ResearcherID 号        ORCID 号
LI, Bing Nan         E-7575-2010         0000-0002-4777-5773
ISSN: 2169-3536
第 235 条,共 261 条
标题: Nonspherical hollow alpha-Fe2O3 structures synthesized by stepwise effect of fluoride and phosphate anions
作者: Wang, CH (Wang, Conghui); Shi, J (Shi, Jing); Cui, XM (Cui, Xinmin); Wang, HX (Wang, Huixiang); Wu, JH (Wu, Jianghong); Zhang, CH (Zhang, Chenghua); Wang, LC (Wang, Liancheng); Lv, BL (Lv, Baoliang); Xu, Y (Xu, Yao)
来源出版物: JOURNAL OF MATERIALS CHEMISTRY A 卷: 4 期: 28 页: 11000-11008 DOI: 10.1039/c6ta03228a 出版年: 2016
摘要: Despite the significant progress in making hollow structures, it is still a challenge to synthesize some specialized hollow structures. In the present work, we obtained a new hollow hematite structure, tube-in-dodecahedron, by using the stepwise influences of fluoride and phosphate anions. Based on condition-dependent experiments, we proposed a "nucleation-aggregation-recrystallition and etching" mechanism, which also directed us to synthesize a series of hematite hollow structures, including hollow dodecahedron and hollow ellipsoid. The concentration of phosphate was found to play a decisive role in the control of these hollow structures. 0.08 mM is the critical point for keeping the top facets of dodecahedral hematite particles while 0.2 mM is the upper limit for keeping the lateral facets. The magnetic properties of these synthesized hollow hematite structures were found to be closely associated with the structures. The synthesized tube-in-dodecahedral hematite particles exhibited excellent photocatalytic reactivity toward organic dyes.
入藏号: WOS:000379473100032
作者识别号:
作者        ResearcherID 号        ORCID 号
Lv, Baoliang         H-2311-2013         0000-0001-8288-6076
wang, liancheng         H-9911-2013         0000-0003-1117-1326
ISSN: 2050-7488
eISSN: 2050-7496
第 236 条,共 261 条
标题: Image dehazing technique based on polarimetric spectral analysis
作者: Xia, P (Xia, Pu); Liu, XB (Liu, Xuebin)
来源出版物: OPTIK 卷: 127 期: 18 页: 7350-7358 DOI: 10.1016/j.ijleo.2016.05.071 出版年: 2016
摘要: Image took under hazy weather suffers from poor contrast and resolution, the haze particles will attenuate the light reflected by the targets and add unwanted scattering light. Based on the fact that the target reflection and scattering light have different polarimetric characteristics, light's power to penetrate the haze particles is linked with wavelength, this paper combines the polarimetric dehazing technique with spectral analysis, firstly proposed the polarimetric spectral dehazing method. A polarimetric spectral imager is used to obtain data under a continuously changing weather circle, the dehazing result is analyzed under five different spectral channels of 451.4 nm, 551.2 nm, 650.9 nm, 750.7 nm and 850.5 nm. The results show that our method can effectively recover the haze degenerated image under visible and infrared channels, the restoration quality of detailed information of the near field and the far-field targets are in varying degrees under different channels. The dehazing process can enhance the image contrast by 1.68-3.64 times under different wavelengths. Two correction factors, which regularity is given for particle use, are introduced to revise an image restoration result. (C) 2016 The Authors. Published by Elsevier GmbH.
入藏号: WOS:000378970700042
ISSN: 0030-4026
第 237 条,共 261 条
标题: Thermochromic VO2 films from ammonium citrato-oxovanadate(IV) with excellent optical and phase transition properties
作者: Zhang, J (Zhang, Jing); Tian, H (Tian, Hong); Hao, L (Hao, Liang); Jin, X (Jin, Xin); Yang, CM (Yang, Chunming); Wang, J (Wang, Jing); Cui, XM (Cui, Xinmin); Wang, CH (Wang, Conghui); Zhang, C (Zhang, Ce); Zhang, C (Zhang, Cong); Xu, Y (Xu, Yao)
来源出版物: JOURNAL OF MATERIALS CHEMISTRY C 卷: 4 期: 23 页: 5281-5288 DOI: 10.1039/c6tc00315j 出版年: 2016
摘要: Thermochromic VO2 film is a potential material for energy-saving windows in future buildings. Considering the difficulty in controlling the valence state and polymorphism during the formation of VO2 (M) film, we propose a facile and safe solution method of fabricating monoclinic (M) VO2 film directly from the newly synthesized ammonium citrato-oxovanadate(IV) compound [(NH4)(4)[V2O2(C6H4O7)(2)]center dot 2H(2)O, denoted as CA-V(IV)], as a vanadium(IV) precursor to stabilize vanadium in the 4+ valence state without utilizing V2O5 as an intermediate or complex post-treatment in vacuum. This new ambient-stable compound CA-V(IV) contains centrosymmetric dinuclear complex anions [{VO(C6H4O7)}(2)](4-), in which the carboxylate groups are coordinated to the V4+ ions in a monodentate fashion and each vanadium atom exhibits distorted octahedral geometry. With a perfect monoclinic phase, the VO2 films possessed excellent thermochromic and visible transmissive properties. Accompanying a change in film thickness from 119 nm to 41 nm, the integral visible transmittance T-vis at 25 degrees C of VO2 films ranged from 38.4% to 70.0%. The maximum visible transmittance (T-max) reached 77.2% for VO2 film with a thickness of 41 nm, which shows that the phase transition of VO2 did not greatly affect the visible transmittance of the film. For the VO2 film with a thickness of 41 nm, of which the visible transmittance modulation (Lambda T-vis = 2.1%) was the largest among the three samples, the solar energy modulation (Delta T-sol) reached 11.3%. Moreover, the transition temperature of our VO2 films was far below that of bulk VO2 (68 degrees C), and the best transition temperature was as low as 50.8 degrees C.
入藏号: WOS:000378273700015
ISSN: 2050-7526
eISSN: 2050-7534
第 238 条,共 261 条
标题: Biomimetic microchannels of planar reactors for optimized photocatalytic efficiency of water purification
作者: Liao, WX (Liao, Wuxia); Wang, N (Wang, Ning); Wang, TS (Wang, Taisheng); Xu, J (Xu, Jia); Han, XD (Han, Xudong); Liu, ZY (Liu, Zhenyu); Zhang, XM (Zhang, Xuming); Yu, WX (Yu, Weixing)
来源出版物: BIOMICROFLUIDICS 卷: 10 期: 1 文献号: 014123 DOI: 10.1063/1.4942947 出版年: JAN 2016
摘要: This paper reports a biomimetic design of microchannels in the planar reactors with the aim to optimize the photocatalytic efficiency of water purification. Inspired from biology, a bifurcated microchannel has been designed based on the Murray's law to connect to the reaction chamber for photocatalytic reaction. The microchannels are designed to have a constant depth of 50 mu m but variable aspect ratios ranging from 0.015 to 0.125. To prove its effectiveness for photocatalytic water purification, the biomimetic planar reactors have been tested and compared with the non-biomimetic ones, showing an improvement of the degradation efficiency by 68%. By employing the finite element method, the flow process of the designed microchannel reactors has been simulated and analyzed. It is found that the biomimetic design owns a larger flow velocity fluctuation than that of the non-biomimetic one, which in turn results in a faster photocatalytic reaction speed. Such a biomimetic design paves the way for the design of more efficient planar reactors and may also find applications in other microfluidic systems that involve the use of microchannels. (c) 2016 AIP Publishing LLC.
入藏号: WOS:000377536500041
PubMed ID: 26958102
会议名称: 5th International Conference on Optofluidics (Optofluidics)
会议日期: JUL 26-29, 2015
会议地点: Taipei, TAIWAN
会议赞助商 : Minist Sci & Technol, Bur Foreign Trade, Natl Taiwan Univ, Academia Sinica, Res Ctr Appl Sci
作者识别号:
作者        ResearcherID 号        ORCID 号
Liu, Zhenyu         E-9551-2010         
Zhang, Xuming                  0000-0002-9326-5547
ISSN: 1932-1058
第 239 条,共 261 条
标题: Segmentation of White Blood Cell from Acute Lymphoblastic Leukemia Images Using Dual-Threshold Method
作者: Li, Y (Li, Yan); Zhu, R (Zhu, Rui); Mi, L (Mi, Lei); Cao, YH (Cao, Yihui); Yao, D (Yao, Di)
来源出版物: COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 文献号: 9514707 DOI: 10.1155/2016/9514707 出版年: 2016
摘要: We propose a dual-threshold method based on a strategic combination of RGB and HSV color space for white blood cell (WBC) segmentation. The proposed method consists of three main parts: preprocessing, threshold segmentation, and postprocessing. In the preprocessing part, we get two images for further processing: one contrast-stretched gray image and one H component image from transformed HSV color space. In the threshold segmentation part, a dual-threshold method is proposed for improving the conventional single-threshold approaches and a golden section search method is used for determining the optimal thresholds. For the postprocessing part, mathematical morphology and median filtering are utilized to denoise and remove incomplete WBCs. The proposed method was tested in segmenting the lymphoblasts on a public Acute Lymphoblastic Leukemia (ALL) image dataset. The results show that the performance of the proposed method is better than single-threshold approach independently performed in RGB and HSV color space and the overall single WBC segmentation accuracy reaches 97.85%, showing a good prospect in subsequent lymphoblast classification and ALL diagnosis.
入藏号: WOS:000377438500001
作者识别号:
作者        ResearcherID 号        ORCID 号
Li, Yan                  0000-0002-4171-4590
ISSN: 1748-670X
eISSN: 1748-6718
第 240 条,共 261 条
标题: Ultra-high Q one-dimensional hybrid PhC-SPP waveguide microcavity with large structure tolerance
作者: Liu, F (Liu, Feng); Zhang, LX (Zhang, Lingxuan); Lu, XY (Lu, Xiaoyuan); Wang, WQ (Wang, Weiqiang); Wang, LR (Wang, Leiran); Wang, GX (Wang, Guoxi); Zhang, WF (Zhang, Wenfu); Zhao, W (Zhao, Wei)
来源出版物: JOURNAL OF MODERN OPTICS 卷: 63 期: 12 页: 1158-1165 DOI: 10.1080/09500340.2015.1130272 出版年: 2016
摘要: A photonic crystal - surface plasmon-polaritons hybrid transverse magnetic mode waveguide based on a one-dimensional optical microcavity is designed to work in the communication band. A Gaussian field distribution in a stepping heterojunction taper is designed by band engineering, and a silica layer compresses the mode field to the subwavelength scale. The designed microcavity possesses a resonant mode with a quality factor of 1609 and a modal volume of 0.01 cubic wavelength. The constant period and the large structure tolerance make it realizable by current processing techniques.
入藏号: WOS:000375151500005
ISSN: 0950-0340
eISSN: 1362-3044
第 241 条,共 261 条
标题: A Method of Removing Reflected Highlight on Images Based on Polarimetric Imaging
作者: Yang, FC (Yang, Fanchao); Tang, XJ (Tang, Xingjia); Hu, BL (Hu, Bingliang); Wei, RY (Wei, Ruyi); Kong, L (Kong, Liang); Li, Y (Li, Yong)
来源出版物: JOURNAL OF SENSORS 文献号: 9537320 DOI: 10.1155/2016/9537320 出版年: 2016
摘要: A method of removing reflected highlight is proposed on polarimetric imaging. Polarization images (0 degrees, 45 degrees, 90 degrees, and 135 degrees) and the reflection angle are required in this reflected light removal algorithm. This method is based on the physical model of reflection and refraction, and no additional image processing algorithm is necessary in this algorithm. Compared to traditional polarization method with single polarizer, restricted observation angle of Brewster is not demanded and multiple reflection areas of different polarization orientations can be removed simultaneously. Experimental results, respectively, demonstrate the features of this reflected light removal algorithm, and it can be considered very suitable in polarization remote sensing.
入藏号: WOS:000375596300001
ISSN: 1687-725X
eISSN: 1687-7268
第 242 条,共 261 条
标题: Multi-channel terahertz wavelength division demultiplexer with defects-coupled photonic crystal waveguide
作者: Li, SP (Li, Shaopeng); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Huang, N (Huang, Nan)
来源出版物: JOURNAL OF MODERN OPTICS 卷: 63 期: 10 页: 955-960 DOI: 10.1080/09500340.2015.1111457 出版年: 2016
摘要: Terahertz (THz) wavelength division demultiplexer based on a compact defects-coupled photonic crystal waveguide is proposed and demonstrated numerically. This device consists of an input waveguide that perpendicularly coupled with a series of defects cavities, each of which captures the resonance frequency from the input waveguide. Coupled-mode theory and finite element method are used to analyze the transmission properties of the structure. It is found that the transmission wavelength centered around 1THz can be adjusted by changing the geometrical parameters of defects cavities, which equals to THz waves generated by optical methods such as difference frequency generation and optical rectification. Applications in this frequency range are urgently needed. Furthermore, the highest transmission efficiency of 0.94 can be achieved when a perfect wavelength-selective mirror is set in the output waveguide.
入藏号: WOS:000373909000006
ISSN: 0950-0340
eISSN: 1362-3044
第 243 条,共 261 条
标题: Broadband antireflective double-layer mesoporous silica coating with strong abrasion-resistance for solar cell glass
作者: Wang, J (Wang, Jing); Yang, CM (Yang, Chunming); Liu, Y (Liu, Yi); Zhang, C (Zhang, Ce); Zhang, C (Zhang, Cong); Wang, MC (Wang, Mengchao); Zhang, J (Zhang, Jing); Cui, XM (Cui, Xinmin); Ding, RM (Ding, Ruimin); Xu, Y (Xu, Yao)
来源出版物: RSC ADVANCES 卷: 6 期: 30 页: 25191-25197 DOI: 10.1039/c6ra02281b 出版年: 2016
摘要: To enhance the efficiency of solar cells, a broadband double-layer antireflective (AR) coating with excellent transmittance and abrasion-resistance, was successfully fabricated using two layer mesoporous silica coatings. Both layers were prepared via a solvent evaporation self-assembly method in which the top- and bottom-layer mesoporous silica coatings used Pluronic F127 and cetyltrimethylammonium bromide (CTAB) as templates, respectively. The grazing incidence small angle X-ray scattering (GISAXS) and the transmission electron microscope (TEM) results indicated that the mesopores in the double-layer AR coating belonged to a Fmmm orthorhombic symmetry structure of the SBA-16 in the top layer and a P-6/mmc 3D-hexagonal structure of the MCM-41 in the bottom layer. The solar-weighted average transmittance (T-PV) of the broadband AR coating is approximately 99.10% on quartz, 98.62% on borosilicate glass, and 98.55% on K9 glass in the solar spectrum range of 300-2400 nm. By introducing broadband AR coating, the overall power conversion efficiency (eta) of the solar cell showed an increase of 1.23% for quartz, 1.31% for borosilicate glass, and 1.37% for K9 glass. Meanwhile, the double-layer AR coating had excellent mechanical stability; the T-PV value of coating after abrasion by CS-10F wearaser only decreased 0.16% on quartz, 0.29% on borosilicate glass and K9 glass. The pencil hardness of the double-layer AR coating was found to be 6H.
入藏号: WOS:000372252700046
ISSN: 2046-2069
第 244 条,共 261 条
标题: SERS activity with tenfold detection limit optimization on a type of nanoporous AAO-based complex multilayer substrate
作者: Sui, CF (Sui, Chaofan); Wang, KG (Wang, Kaige); Wang, S (Wang, Shuang); Ren, JY (Ren, Junying); Bai, XH (Bai, Xiaohong); Bai, JT (Bai, Jintao)
来源出版物: NANOSCALE 卷: 8 期: 11 页: 5920-5927 DOI: 10.1039/c5nr06771e 出版年: 2016
摘要: Most of SERS applications are constricted by heterogeneous hotspots and aggregates of nanostructure, which result in low sensitivity and poor reproducibility of characteristic signals. This work intends to introduce SERS properties of a type of SERS-active substrate, Au-CuCl2-AAO, which is innovatively developed on a porous anodic alumina oxide (AAO) template. Spectral measuring results of Rhodamine 6G (R6G) on this substrate optimized by controlling morphology and gold thickness showed that enhancement factor (2.30 x 10(7)) and detection limit (10(-10) M) were both improved and represented better performance than its template AAO. Homogenous hot spots across the region of interest were achieved by scanning SERS intensity distribution for the band at 1505 cm(-1) in 5 x 5 mu m(2) area. Furthermore, the promising SERS activity of the flower-patterned substrate was theoretically explained through simulation of the electromagnetic field distribution. In addition, this SERS substrate is proposed for applications within the field of chemical and biochemical analyses.
入藏号: WOS:000372245900016
PubMed ID: 26911325
ISSN: 2040-3364
eISSN: 2040-3372
第 245 条,共 261 条
标题: The degree of polarization modeling with different shapes of the satellite
作者: Yao, DL (Yao, Dalei); Wen, DS (Wen, Desheng); Qiu, YH (Qiu, Yuehong); Xi, JB (Xi, Jiangbo); Wen, Y (Wen, Yan); Chen, Z (Chen, Zhi)
来源出版物: OPTIK 卷: 127 期: 4 页: 1860-1866 DOI: 10.1016/j.ijleo.2015.09.172 出版年: 2016
摘要: Polarization is one of the important characteristics of the interaction between light and substance, which relates to the shape and the material of the target. To research the effects of the degree of polarization (DOP) caused by different materials, the polarized bidirectional reflectance distribution function (pBRDF) model has been established by the theory of microfacet But in this model, the scattering effect of polyhedron is ignored. Based on these researches, the DOP model of satellite with different shapes (cuboid, cylinder and sphere) is set up and simulated. The simulating results show that the DOP of satellite relates with the complex refractive index, shape of satellite, incident angle and view angle. It is also proved that the polarization is a reflection of the characteristics of material, shape of satellite, which provides theoretical support for identifying satellite. (C) 2015 Published by Elsevier GmbH.
入藏号: WOS:000370097900055
ISSN: 0030-4026
第 246 条,共 261 条
标题: Optical properties and Judd-Ofelt analysis of a novel europium pentafluoropropionate complex with 2,2 '-bipyridine
作者: Li, DD (Li, Dong-dong); She, JB (She, Jiang-bo); Nie, RZ (Nie, Rong-zhi); Peng, B (Peng, Bo)
来源出版物: OPTIK 卷: 127 期: 4 页: 2059-2061 DOI: 10.1016/j.ijleo.2015.11.130 出版年: 2016
摘要: Europium pentafluoropropionate 2,2'-bipyridine complex, Eu(C2F5COO)(3)center dot bpy (bpy= 2,2'-bipyridine), were synthesized and characterized by elemental analysis, Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectroscopy and thermogravimetric analysis (TA).The excitation spectra of the complex demonstrate that the energy collected by "antenna ligands" was transferred to Eu3+ ions efficiently. The room-temperature PL spectra of the complex is composed of the typical Eu3+ ions red emission, due to transitions between D-5(0) -> F-7(J(J=0 -> 4)). The lifetimes of D-5(0) of Eu3+ in the complex were examined using time-resolved spectroscopic analysis, and the lifetime values of Eu(C2F5COO)(3)center dot bPY were fitting with monoexponential (2585 mu s) curve. The decomposition temperature of the complex was 262 degrees C, which indicates the host complex was quite stable to heat. According to the fluorescence emission spectra, the Judd-Ofelt parameters Omega(2), Omega(4) of the complexes were calculated and the radiative properties were also presented. The D-5(0) radiative lifetime, quantum yield and the stimulated emission cross-section of the complex is excellent, which prove that this complex will be promising material for laser application. (C) 2015 Elsevier GmbH. All rights reserved.
入藏号: WOS:000370097900091
ISSN: 0030-4026
第 247 条,共 261 条
标题: A kind of infrared expand depth of field vision sensor in low-visibility road condition for safety-driving
作者: Wang, HF (Wang, Hui-feng); Wang, GP (Wang, Gui-ping); Wang, XY (Wang, Xiao-yan); Ruan, C (Ruan, Chi); Chen, SQ (Chen, Shi-qin)
来源出版物: SENSOR REVIEW 卷: 36 期: 1 页: 7-13 DOI: 10.1108/SR-04-2015-0055 出版年: 2016
摘要: Purpose - This study aims to consider active vision in low-visibility environments to reveal the factors of optical properties which affect visibility and to explore a method of obtaining different depths of fields by multimode imaging. Bad weather affects the driver's visual range tremendously and thus has a serious impact on transport safety.
Design/methodology/approach - A new mechanism and a core algorithm for obtaining an excellent large field-depth image which can be used to aid safe driving is designed and implemented. In this mechanism, atmospheric extinction principle and field expansion system are researched as the basis, followed by image registration and fusion algorithm for the Infrared Extended Depth of Field (IR-EDOF) sensor.
Findings - The experimental results show that the idea we propose can work well to expand the field depth in a low-visibility road environment as a new aided safety-driving sensor.
Originality/value - The paper presents a new kind of active optical extension, as well as enhanced driving aids, which is an effective solution to the problem of weakening of visual ability. It is a practical engineering sensor scheme for safety driving in low-visibility road environments.
入藏号: WOS:000369521000002
ISSN: 0260-2288
eISSN: 1758-6828
第 248 条,共 261 条
标题: Impact of Light Polarization on the Measurement of Water Particulate Backscattering Coefficient
作者: Liu, J (Liu Jia); Gong, F (Gong Fang); He, XQ (He Xian-qiang); Zhu, QK (Zhu Qian-kun); Huang, HQ (Huang Hai-qing)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 36 期: 1 页: 31-37 DOI: 10.3964/j.issn.1000-0593(2016)01-0031-07 出版年: JAN 2016
摘要: Particulate backscattering coefficient is a main inherent optical properties (IOPs) of water, which is also a determining factor of ocean color and a basic parameter for inversion of satellite ocean color remote sensing. In-situ measurement with optical instruments is currently the main method for obtaining the particulate backscattering coefficient of water. Due to reflection and refraction by the mirrors in the instrument optical path, the emergent light source from the instrument may be partly polarized, thus to impact the measurement accuracy of water backscattering coefficient. At present, the light polarization of measuring instruments and its impact on the measurement accuracy of particulate backscattering coefficient are still poorly known. For this reason, taking a widely used backscattering coefficient measuring instrument HydroScat6 (HS-6) as an example in this paper, the polarization characteristic of the emergent light from the instrument was systematically measured, and further experimental study on the impact of the light polarization on the measurement accuracy of the particulate backscattering coefficient of water was carried out. The results show that the degree of polarization(DOP) of the central wavelength of emergent light ranges from 20% to 30% for all of the six channels of the HS-6, except the 590 nm channel from which the DOP of the emergent light is slightly low (similar to 15%). Therefore, the emergent light from the HS-6 has significant polarization. Light polarization has non-neglectable impact on the measurement of particulate backscattering coefficient, and the impact degree varies with the wave band, linear polarization angle and suspended particulate matter (SPM) concentration. At different SPM concentrations, the mean difference caused by light polarization can reach 15.49%, 11.27%, 12.79%, 14.43%, 13.76%, and 12.46% in six bands, 420, 442, 470, 510, 590, and 670 nm, respectively. Consequently, the impact of light polarization on the measurement of particulate backscattering coefficient with an optical instrument should be taken into account, and the DOP of the emergent light should be reduced as much as possible.
入藏号: WOS:000368043800007
ISSN: 1000-0593
第 249 条,共 261 条
标题: Spectral Multimodal Hashing and Its Application to Multimedia Retrieval
作者: Zhen, Y (Zhen, Yi); Gao, Y (Gao, Yue); Yeung, DY (Yeung, Dit-Yan); Zha, HY (Zha, Hongyuan); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 1 页: 27-38 DOI: 10.1109/TCYB.2015.2392052 出版年: JAN 2016
摘要: In recent years, multimedia retrieval has sparked much research interest in the multimedia, pattern recognition, and data mining communities. Although some attempts have been made along this direction, performing fast multimodal search at very large scale still remains a major challenge in the area. While hashing-based methods have recently achieved promising successes in speeding-up large-scale similarity search, most existing methods are only designed for uni-modal data, making them unsuitable for multimodal multimedia retrieval. In this paper, we propose a new hashing-based method for fast multimodal multimedia retrieval. The method is based on spectral analysis of the correlation matrix of different modalities. We also develop an efficient algorithm that learns some parameters from the data distribution for obtaining the binary codes. We empirically compare our method with some state-of-the-art methods on two real-world multimedia data sets.
入藏号: WOS:000367144300004
PubMed ID: 26208374
ISSN: 2168-2267
eISSN: 2168-2275
第 250 条,共 261 条
标题: Learning Spatio-Temporal Representations for Action Recognition: A Genetic Programming Approach
作者: Liu, L (Liu, Li); Shao, L (Shao, Ling); Li, XL (Li, Xuelong); Lu, K (Lu, Ke)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 1 页: 158-170 DOI: 10.1109/TCYB.2015.2399172 出版年: JAN 2016
摘要: Extracting discriminative and robust features from video sequences is the first and most critical step in human action recognition. In this paper, instead of using handcrafted features, we automatically learn spatio-temporal motion features for action recognition. This is achieved via an evolutionary method, i.e., genetic programming (GP), which evolves the motion feature descriptor on a population of primitive 3D operators (e.g., 3D-Gabor and wavelet). In this way, the scale and shift invariant features can be effectively extracted from both color and optical flow sequences. We intend to learn data adaptive descriptors for different datasets with multiple layers, which makes fully use of the knowledge to mimic the physical structure of the human visual cortex for action recognition and simultaneously reduce the GP searching space to effectively accelerate the convergence of optimal solutions. In our evolutionary architecture, the average cross-validation classification error, which is calculated by an support-vector-machine classifier on the training set, is adopted as the evaluation criterion for the GP fitness function. After the entire evolution procedure finishes, the best-so-far solution selected by GP is regarded as the (near-) optimal action descriptor obtained. The GP-evolving feature extraction method is evaluated on four popular action datasets, namely KTH, HMDB51, UCF YouTube, and Hollywood2. Experimental results show that our method significantly outperforms other types of features, either hand-designed or machine-learned.
入藏号: WOS:000367144300015
PubMed ID: 25700480
ISSN: 2168-2267
eISSN: 2168-2275

第 251 条,共 261 条
标题: Weakly Supervised Human Fixations Prediction
作者: Zhang, LM (Zhang, Luming); Li, XL (Li, Xuelong); Nie, LQ (Nie, Liqiang); Yang, Y (Yang, Yi); Xia, YJ (Xia, Yingjie)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 46 期: 1 页: 258-269 DOI: 10.1109/TCYB.2015.2400821 出版年: JAN 2016
摘要: Automatically predicting human eye fixations is a useful technique that can facilitate many multimedia applications, e.g., image retrieval, action recognition, and photo retargeting. Conventional approaches are frustrated by two drawbacks. First, psychophysical experiments show that an object-level interpretation of scenes influences eye movements significantly. Most of the existing saliency models rely on object detectors, and therefore, only a few prespecified categories can be discovered. Second, the relative displacement of objects influences their saliency remarkably, but current models cannot describe them explicitly. To solve these problems, this paper proposes weakly supervised fixations prediction, which leverages image labels to improve accuracy of human fixations prediction. The proposed model hierarchically discovers objects as well as their spatial configurations. Starting from the raw image pixels, we sample superpixels in an image, thereby seamless object descriptors termed object-level graphlets (oGLs) are generated by random walking on the superpixel mosaic. Then, a manifold embedding algorithm is proposed to encode image labels into oGLs, and the response map of each prespecified object is computed accordingly. On the basis of the object-level response map, we propose spatial-level graphlets (sGLs) to model the relative positions among objects. Afterward, eye tracking data is employed to integrate these sGLs for predicting human eye fixations. Thorough experiment results demonstrate the advantage of the proposed method over the state-of-the-art.
入藏号: WOS:000367144300023
PubMed ID: 26168451
作者识别号:
作者        ResearcherID 号        ORCID 号
Yang, Yi         B-9273-2017         0000-0001-5528-0546
ISSN: 2168-2267
eISSN: 2168-2275
第 252 条,共 261 条
标题: Joint Multilabel Classification With Community-Aware Label Graph Learning
作者: Li, X (Li, Xi); Zhao, XY (Zhao, Xueyi); Zhang, ZF (Zhang, Zhongfei); Wu, F (Wu, Fei); Zhuang, YT (Zhuang, Yueting); Wang, JD (Wang, Jingdong); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 25 期: 1 页: 484-493 DOI: 10.1109/TIP.2015.2503700 出版年: JAN 2016
摘要: As an important and challenging problem in machine learning and computer vision, multilabel classification is typically implemented in a max-margin multilabel learning framework, where the inter-label separability is characterized by the sample-specific classification margins between labels. However, the conventional multilabel classification approaches are usually incapable of effectively exploring the intrinsic inter-label correlations as well as jointly modeling the interactions between inter-label correlations and multilabel classification. To address this issue, we propose a multilabel classification framework based on a joint learning approach called label graph learning (LGL) driven weighted Support Vector Machine (SVM). In principle, the joint learning approach explicitly models the inter-label correlations by LGL, which is jointly optimized with multilabel classification in a unified learning scheme. As a result, the learned label correlation graph well fits the multilabel classification task while effectively reflecting the underlying topological structures among labels. Moreover, the inter-label interactions are also influenced by label-specific sample communities (each community for the samples sharing a common label). Namely, if two labels have similar label-specific sample communities, they are likely to be correlated. Based on this observation, LGL is further regularized by the label Hypergraph Laplacian. Experimental results have demonstrated the effectiveness of our approach over several benchmark data sets.
入藏号: WOS:000367257100004
PubMed ID: 26625416
作者识别号:
作者        ResearcherID 号        ORCID 号
Li, Xi         L-1234-2013         
ISSN: 1057-7149
eISSN: 1941-0042
第 253 条,共 261 条
标题: Shape-Constrained Sparse and Low-Rank Decomposition for Auroral Substorm Detection
作者: Yang, X (Yang, Xi); Gao, XB (Gao, Xinbo); Tao, DC (Tao, Dacheng); Li, XL (Li, Xuelong); Han, B (Han, Bing); Li, J (Li, Jie)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 27 期: 1 页: 32-46 DOI: 10.1109/TNNLS.2015.2411613 出版年: JAN 2016
摘要: An auroral substorm is an important geophysical phenomenon that reflects the interaction between the solar wind and the Earth's magnetosphere. Detecting substorms is of practical significance in order to prevent disruption to communication and global positioning systems. However, existing detection methods can be inaccurate or require time-consuming manual analysis and are therefore impractical for large-scale data sets. In this paper, we propose an automatic auroral substorm detection method based on a shape-constrained sparse and low-rank decomposition (SCSLD) framework. Our method automatically detects real substorm onsets in large-scale aurora sequences, which overcomes the limitations of manual detection. To reduce noise interference inherent in current SLD methods, we introduce a shape constraint to force the noise to be assigned to the low-rank part (stationary background), thus ensuring the accuracy of the sparse part (moving object) and improving the performance. Experiments conducted on aurora sequences in solar cycle 23 (1996-2008) show that the proposed SCSLD method achieves good performance for motion analysis of aurora sequences. Moreover, the obtained results are highly consistent with manual analysis, suggesting that the proposed automatic method is useful and effective in practice.
入藏号: WOS:000367253200004
PubMed ID: 25826810
ISSN: 2162-237X
eISSN: 2162-2388
第 254 条,共 261 条
标题: Study of a symmetrically structured SPR sensor and its dual-wavelength differential method
作者: Yang, HM (Yang, Hai-ma); Ma, CW (Ma, Cai-wen); Wang, JY (Wang, Jian-yu); Liu, J (Liu, Jin); Chen, BX (Chen, Bao-xue)
来源出版物: JOURNAL OF MODERN OPTICS 卷: 63 期: 2 页: 85-91 DOI: 10.1080/09500340.2015.1066455 出版年: 2016
摘要: This study investigates a novel structure for surface plasmon resonance sensing and its dual-wavelength differential method. The surface plasmon wave is excited by a planar waveguide, which is prepared through the ion-exchange method. The distribution of refractive indices is fitted by the Fermi function. The sensing structure is based on a symmetric structure with a metal layer, a measured medium, and another metal layer. The condition for refractive index matching changes with the thicknesses of test samples, thus the test range can be adjusted using this structure. Given two appropriate wavelengths lambda(1) and lambda(2) for detection by the intensity method and an increase in the refractive index, the intensity variety at lambda(1) can be positive, whereas that at lambda(2) can be negative. When the refractive indices are determined based on differential values, sensitivity is improved. Solutions with refractive index values ranging from 1.33 to 1.428 are detected in the experiments using the single-wavelength method and the dual-wavelength differential method. Results show that the differential detection method enhances the adjustability and sensitivity of the SPR sensor in combination with a symmetric structure.
入藏号: WOS:000367159300001
ISSN: 0950-0340
eISSN: 1362-3044
第 255 条,共 261 条
标题: High-sensitivity plasmonic sensor based on perfect absorber with metallic nanoring structures
作者: Lu, XY (Lu, Xiaoyuan); Wan, RG (Wan, Rengang); Liu, F (Liu, Feng); Zhang, TY (Zhang, Tongyi)
来源出版物: JOURNAL OF MODERN OPTICS 卷: 63 期: 2 页: 177-183 DOI: 10.1080/09500340.2015.1066459 出版年: 2016
摘要: We propose a nanoring array structure backed by a metal mirror to achieve perfect infrared absorber with absorption as high as 99.99%. The frequency of the absorption peak strongly depends on the refractive index surrounding the structured surface, while the maximum of absorption remains constant with varying the surrounding refractive index. These features can be used as plasmonic sensor for refractive index measurement. This plasmonic sensor possesses the figure of merit 700. In addition, we investigate the effect of various materials on the performance of the sensor, including SiO2, TiO2, TiN, and Al2O3 dielectric spacer and Au, Ag, Al, and Cu back plate and top structure. Due to the high sensitivity and simple sensing scheme, the sensing strategy can find potential applications in chemical and biosensor applications.
入藏号: WOS:000367159300011
ISSN: 0950-0340
eISSN: 1362-3044
第 256 条,共 261 条
标题: Terahertz narrow-band filter based on rectangle photonic crystal
作者: Lu, YG (Lu, Yangang); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu)
来源出版物: JOURNAL OF MODERN OPTICS 卷: 63 期: 3 页: 224-230 DOI: 10.1080/09500340.2015.1073808 出版年: 2016
摘要: A terahertz filter with a channel drop cavity and a resonant reflection cavity in a two-dimensional photonic crystal is theoretically proposed. The channel drop cavity is used to trap photons at resonant frequency from the bus waveguide through coupling and emit them to a drop waveguide, while the resonant reflection cavity is used to realize wavelength selective reflection feedback in the bus waveguide. The transmission properties of the terahertz filter are simulated using the finite element method. It is found that a peak with the central frequency of 1.12 THz is existed in the transmission spectrum. The full width at half maximum of the passband is only 5 GHz, and the peak drop efficiency is up to 94.8%.
入藏号: WOS:000367162300007
作者识别号:
作者        ResearcherID 号        ORCID 号
Liu, Hongjun         D-2541-2016         
ISSN: 0950-0340
eISSN: 1362-3044
第 257 条,共 261 条
标题: Broadband and efficient wavelength conversion in a slot-width switching silicon-organic hybrid waveguide
作者: Bai, XX (Bai, Xinxin); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu)
来源出版物: JOURNAL OF MODERN OPTICS 卷: 63 期: 3 页: 231-238 DOI: 10.1080/09500340.2015.1073809 出版年: 2016
摘要: We propose a slot-width switching (SWS) silicon-organic hybrid waveguide for broadband and efficient wavelength conversion. By switching the slot width of different lengths, the quasi-phase-matching can be obtained. Compared with width-modulated silicon-on-insulator (SOI) waveguide, the non-linear absorption can be ignored in slot waveguide which is filled with p-toluene sulphonate. Consequently, the conversion efficiency at a particular signal wavelength is improved, and the 3-dB conversion bandwidth is also extended. The numerical simulation results indicate that, for a continuous-wave pump at 1550 nm, a conversion bandwidth of 570 nm and a peak conversion efficiency of 11.32 dB can be realized in a 7.5-mm-long SWS waveguide, which is better than that of width-modulated SOI waveguide.
入藏号: WOS:000367162300008
作者识别号:
作者        ResearcherID 号        ORCID 号
Liu, Hongjun         D-2541-2016         
ISSN: 0950-0340
eISSN: 1362-3044
第 258 条,共 261 条
标题: Impact of evolving surface nanoscale topologies in femtosecond laser structuring of Ni-based superalloy CMSX-4
作者: Li, C (Li, Chen); Cheng, GH (Cheng, Guang-Hua); Colombier, JP (Colombier, Jean-Philippe); Faure, N (Faure, Nicolas); Reynaud, S (Reynaud, Stephanie); Zhang, H (Zhang, Hao); Jamon, D (Jamon, Damien); Stoian, R (Stoian, Razvan)
来源出版物: JOURNAL OF OPTICS 卷: 18 期: 1 文献号: 015402 DOI: 10.1088/2040-8978/18/1/015402 出版年: JAN 2016
摘要: We investigate the role of surface nanoscale topographies in the inhomogeneous coupling of laser radiation to Ni-based superalloy CMSX-4 surfaces and in the formation of laser-induced periodic surface structures. The initial surface arbitrary roughness is already able, upon laser exposure, to induce low-spatial-frequency and high-spatial-frequency structures, actively determining an interference of incoming and scattered fields resulting in spatial energy modulation. A topology variation with the incoming dose via the number of pulses determines a correlated evolution in the regular ripple arrangements. The scattering pattern is severely influenced by the scattering source geometries. Therefore, we equally study experimentally the role of one-dimensional nanoscale grooves in determining polarization-dependent structuring patterns at increasing irradiation dose. Finally, the role of surface nanostructures in generating the surface modulation of deposited energy is analyzed by finite-difference-time-domain simulation. Ripple formation in multi-pulses is a result of the feedback process between light and nanostructures.
入藏号: WOS:000367187000026
作者识别号:
作者        ResearcherID 号        ORCID 号
Colombier, Jean-Philippe         B-8884-2012         0000-0001-8462-7019
ISSN: 2040-8978
eISSN: 2040-8986
第 259 条,共 261 条
标题: Single-beam phase retrieval with partially coherent light illumination
作者: Zhou, ML (Zhou, Meiling); Min, JW (Min, Junwei); Gao, P (Gao, Peng); Liang, YS (Liang, Yansheng); Lei, M (Lei, Ming); Yao, BL (Yao, Baoli)
来源出版物: JOURNAL OF OPTICS 卷: 18 期: 1 文献号: 015701 DOI: 10.1088/2040-8978/18/1/015701 出版年: JAN 2016
摘要: A single-beam phase retrieval method with partially coherent illumination is proposed. By using an obverse and reverse iterative (ORI) algorithm, objects can be reconstructed within less time by recording a sequence of diffraction patterns at different axial planes under partially coherent light illumination. Partially coherent light illumination reduces coherent noise and the number of diffraction patterns needed for reconstruction. Thus, the whole process is fast and has high immunity to external perturbation due to the reference-less configuration. Both simulation and experimental results are presented to demonstrate the feasibility of the proposed approach.
入藏号: WOS:000367187000044
ISSN: 2040-8978
eISSN: 2040-8986
第 260 条,共 261 条
标题: Effective transfer of micron-size graphene to microfibers for photonic applications
作者: Wu, XQ (Wu, Xiaoqin); Yu, SL (Yu, Shaoliang); Yang, HR (Yang, Huiran); Li, WL (Li, Wenlei); Liu, XM (Liu, Xueming); Tong, LM (Tong, Limin)
来源出版物: CARBON 卷: 96 页: 1114-1119 DOI: 10.1016/j.carbon.2015.10.069 出版年: JAN 2016
摘要: We demonstrate an effective approach to transferring micron-size CVD graphene layers onto freestanding microfibers. With micro-manipulation, the coating position and length of the graphene films can be precisely controlled. By coating micrometer-scale (e.g., 20 mu M) graphene films onto microfibers with diameters down to 1 mu m, we can achieve significantly enhanced light-graphene interaction (e.g., a low saturable-absorption threshold of 40 MW/cm(2)) and simultaneously maintain a high transmission (73% in maximum) as well. In addition, we use these microscale CVD graphene-coated microfibers (GCMs) as saturable absorbers for all-optical modulation at 1550-nm wavelength with a modulation depth of 12% and passively mode-locked fiber lasing with pulse duration down to 970 fs. (C) 2015 Elsevier Ltd. All rights reserved.
入藏号: WOS:000366078000131
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhejiang University, Dep. Optical Eng.         G-9022-2011         
ISSN: 0008-6223
eISSN: 1873-3891
第 261 条,共 261 条
标题: Unsupervised Band Selection Based on Evolutionary Multiobjective Optimization for Hyperspectral Images
作者: Gong, MG (Gong, Maoguo); Zhang, MY (Zhang, Mingyang); Yuan, Y (Yuan, Yuan)
来源出版物: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 卷: 54 期: 1 页: 544-557 DOI: 10.1109/TGRS.2015.2461653 出版年: JAN 2016
摘要: Band selection is an important preprocessing step for hyperspectral image processing. Many valid criteria have been proposed for band selection, and these criteria model band selection as a single-objective optimization problem. In this paper, a novel multiobjective model is first built for band selection. In this model, two objective functions with a conflicting relationship are designed. One objective function is set as information entropy to represent the information contained in the selected band subsets, and the other one is set as the number of selected bands. Then, based on this model, a new unsupervised band selection method called multiobjective optimization band selection (MOBS) is proposed. In the MOBS method, these two objective functions are optimized simultaneously by a multiobjective evolutionary algorithm to find the best tradeoff solutions. The proposed method shows two unique characters. It can obtain a series of band subsets with different numbers of bands in a single run to offer more options for decision makers. Moreover, these band subsets with different numbers of bands can communicate with each other and have a coevolutionary relationship, which means that they can be optimized in a cooperative way. Since it is unsupervised, the proposed algorithm is compared with some related and recent unsupervised methods for hyperspectral image band selection to evaluate the quality of the obtained band subsets. Experimental results show that the proposed method can generate a set of band subsets with different numbers of bands in a single run and that these band subsets have a stable good performance on classification for different data sets.
入藏号: WOS:000364833900042
ISSN: 0196-2892
eISSN: 1558-0644

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