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2017年12月
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第 1 条,共 255 条
标题: Generation of Circular Optical Vortex Array
作者: Ma, HX (Ma, Haixiang); Li, XZ (Li, Xinzhong); Tai, YP (Tai, Yuping); Li, HH (Li, Hehe); Wang, JG (Wang, Jingge); Tang, MM (Tang, Miaomiao); Tang, J (Tang, Jie); Wang, YS (Wang, Yishan); Nie, ZG (Nie, Zhaogang)
来源出版物: ANNALEN DER PHYSIK 卷: 529 期: 12 文献号: 1700285 DOI: 10.1002/andp.201700285 出版年: DEC 2017
摘要: We report on a novel optical vortex array named circular optical vortex array, which is generated by the superposition of two concentric perfect optical vortices. The circular optical vortex array has a constant topological charge of +1 or -1, the number and sign of which are determined by the topological charges of the two perfect optical vortices. Moreover, the radius of the circular optical vortex array is easily adjusted by using the cone angle of an axicon. Furthermore, the circular optical vortex array and multiple circular optical vortex array can be rotated by changing the initial phase difference of the perfect optical vortices on demand. This work demonstrates a complex structured optical field, which is of significance for applications such as optical tweezers, micro-particle manipulation, and optical imaging.
入藏号: WOS:000417031900013
ISSN: 0003-3804
eISSN: 1521-3889
第 2 条,共 255 条
标题: Influence of Layup and Curing on the Surface Accuracy in the Manufacturing of Carbon Fiber Reinforced Polymer (CFRP) Composite Space Mirrors
作者: Yang, ZY (Yang, Zhiyong); Zhang, JB (Zhang, Jianbao); Xie, YJ (Xie, Yongjie); Zhang, BM (Zhang, Boming); Sun, BG (Sun, Baogang); Guo, HJ (Guo, Hongjun)
来源出版物: APPLIED COMPOSITE MATERIALS 卷: 24 期: 6 页: 1447-1458 DOI: 10.1007/s10443-017-9595-7 出版年: DEC 2017
摘要: Carbon fiber reinforced polymer, CFRP, composite materials have been used to fabricate space mirror. Usually the composite space mirror can completely replicate the high-precision surface of mould by replication process, but the actual surface accuracy of replicated space mirror is always reduced, still needed further study. We emphatically studied the error caused by layup and curing on the surface accuracy of space mirror through comparative experiments and analyses, the layup and curing influence factors include curing temperature, cooling rate of curing, method of prepreg lay-up, and area weight of fiber. Focusing on the four factors, we analyzed the error influence rule and put forward corresponding control measures to improve the surface figure of space mirror. For comparative analysis, six CFRP composite mirrors were fabricated and surface profile of mirrors were measured. Four guiding control measures were described here. Curing process of composite space mirror is our next focus.
入藏号: WOS:000416529500011
ISSN: 0929-189X
eISSN: 1573-4897
第 3 条,共 255 条
标题: Cascade Learning by Optimally Partitioning
作者: Pang, YW (Pang, Yanwei); Cao, JL (Cao, Jiale); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 47 期: 12 页: 4148-4161 DOI: 10.1109/TCYB.2016.2601438 出版年: DEC 2017
摘要: Cascaded AdaBoost classifier is a well-known efficient object detection algorithm. The cascade structure has many parameters to be determined. Most of existing cascade learning algorithms are designed by assigning detection rate and false positive rate to each stage either dynamically or statically. Their objective functions are not directly related to minimum computation cost. These algorithms are not guaranteed to have optimal solution in the sense of minimizing computation cost. On the assumption that a strong classifier is given, in this paper, we propose an optimal cascade learning algorithm (iCascade) which iteratively partitions the strong classifiers into two parts until predefined number of stages are generated. iCascade searches the optimal partition point r(i) of each stage by directly minimizing the computation cost of the cascade. Theorems are provided to guarantee the existence of the unique optimal solution. Theorems are also given for the proposed efficient algorithm of searching optimal parameters ri. Once a new stage is added, the parameter ri for each stage decreases gradually as iteration proceeds, which we call decreasing phenomenon. Moreover, with the goal of minimizing computation cost, we develop an effective algorithm for setting the optimal threshold of each stage. In addition, we prove in theory why more new weak classifiers in the current stage are required compared to that of the previous stage. Experimental results on face detection and pedestrian detection demonstrate the effectiveness and efficiency of the proposed algorithm.
入藏号: WOS:000415727200012
PubMed ID: 28113530
ISSN: 2168-2267
eISSN: 2168-2275
第 4 条,共 255 条
标题: Constrained Low-Rank Learning Using Least Squares-Based Regularization
作者: Li, P (Li, Ping); Yu, J (Yu, Jun); Wang, M (Wang, Meng); Zhang, LM (Zhang, Luming); Cai, D (Cai, Deng); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 47 期: 12 页: 4250-4262 DOI: 10.1109/TCYB.2016.2623638 出版年: DEC 2017
摘要: Low-rank learning has attracted much attention recently due to its efficacy in a rich variety of real-world tasks, e.g., subspace segmentation and image categorization. Most low-rank methods are incapable of capturing low-dimensional subspace for supervised learning tasks, e.g., classification and regression. This paper aims to learn both the discriminant low-rank representation (LRR) and the robust projecting subspace in a supervised manner. To achieve this goal, we cast the problem into a constrained rank minimization framework by adopting the least squares regularization. Naturally, the data label structure tends to resemble that of the corresponding low-dimensional representation, which is derived from the robust subspace projection of clean data by low-rank learning. Moreover, the low-dimensional representation of original data can be paired with some informative structure by imposing an appropriate constraint, e.g., Laplacian regularizer. Therefore, we propose a novel constrained LRR method. The objective function is formulated as a constrained nuclear norm minimization problem, which can be solved by the inexact augmented Lagrange multiplier algorithm. Extensive experiments on image classification, human pose estimation, and robust face recovery have confirmed the superiority of our method.
入藏号: WOS:000415727200020
PubMed ID: 27849552
作者识别号:
作者        ResearcherID 号        ORCID 号
Li, Ping                  0000-0002-8515-7773
ISSN: 2168-2267
eISSN: 2168-2275
第 5 条,共 255 条
标题: Convex Multiview Semi-Supervised Classification
作者: Nie, FP (Nie, Feiping); Li, J (Li, Jing); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 26 期: 12 页: 5718-5729 DOI: 10.1109/TIP.2017.2746270 出版年: DEC 2017
摘要: In many practical applications, there are a great number of unlabeled samples available, while labeling them is a costly and tedious process. Therefore, how to utilize unlabeled samples to assist digging out potential information about the problem is very important. In this paper, we study a multiclass semi-supervised classification task in the context of multiview data. First, an optimization method named Parametric multiview semi-supervised classification (PMSSC) is proposed, where the built classifier for each individual view is explicitly combined with a weight factor. By analyzing the weakness of it, a new adapted weight learning strategy is further formulated, and we come to the convex multiview semi-supervised classification (CMSSC) method. Comparing with the PMSSC, this method has two significant properties. First, without too much loss in performance, the newly used weight learning technique achieves eliminating a hyperparameter, and thus it becomes more compact in form and practical to use. Second, as its name implies, the CMSSC models a convex problem, which avoids the local-minimum problem. Experimental results on several multiview data sets demonstrate that the proposed methods achieve better performances than recent representative methods and the CMSSC is preferred due to its good traits.
入藏号: WOS:000412433000008
ISSN: 1057-7149
eISSN: 1941-0042
第 6 条,共 255 条
标题: High power, high efficiency continuous-wave 808 nm laser diode arrays
作者: Wang, ZF (Wang, Zhenfu); Li, T (Li, Te); Yang, GW (Yang, Guowen); Song, YF (Song, Yunfei)
来源出版物: OPTICS AND LASER TECHNOLOGY 卷: 97 页: 297-301 DOI: 10.1016/j.optlastec.2017.07.015 出版年: DEC 1 2017
摘要: The continuous-wave 100 W-class 808 nm laser diode arrays with extremely high power conversion efficiency of 68% were reported at the heatsink temperature of 25 degrees C. To the best of our knowledge, this was the highest power conversion efficiency at continuous-wave 106 W 808 nm laser diode array with 50% fill factor so far. An asymmetric broad waveguide epitaxial structure with very low internal optical loss of 0.5 cm(-1) was presented. In order to improve the efficiency, various fill factor devices were studied. The 50 W laser diode array with 30% fill factoir and 1.0 mm cavity length demonstrated power conversion efficiency of 71% at heatsink temperature of 15 degrees C. (C) 2017 Elsevier Ltd. All rights reserved.
入藏号: WOS:000409284800039
ISSN: 0030-3992
eISSN: 1879-2545
第 7 条,共 255 条
标题: MoS2-wrapped microfiber-based multi-wavelength soliton fiber laser
作者: Lu, FF (Lu, Feifei)
来源出版物: MODERN PHYSICS LETTERS B 卷: 31 期: 32 文献号: 1750303 DOI: 10.1142/S0217984917503031 出版年: NOV 20 2017
摘要: The single-, dual- and triple-wavelength passively mode-locked erbium-doped fiber lasers are demonstrated with MoS2 and polarization-dependent isolator (PD-ISO). The saturable absorber is fabricated by wrapping an MoS2 around a microfiber. The intracavity PD-ISO acts as a wavelength-tunable filter with a polarization controller (PC) by adjusting the linear birefringence. Single-wavelength mode-locked fiber laser can self-start with suitable pump power. With appropriate PC state, dual- and triple-wavelength operations can be observed when gains at different wavelengths reach a balance. It is noteworthy that dual-wavelength pulses exhibiting peak and dip sidebands, respectively, are demonstrated in the experiment. The proposed simple and multi-wavelength all-fiber conventional soliton lasers could possess potential applications in numerous fields, such as sensors, THz generations and optical communications.
入藏号: WOS:000415767000010
ISSN: 0217-9849
eISSN: 1793-6640
第 8 条,共 255 条
标题: Ultrafast all-optical imaging technique using low-temperature grown GaAs/AlxGa1-xAs multiple-quantum-well semiconductor
作者: Gao, GL (Gao, Guilong); Tian, JS (Tian, Jinshou); Wang, T (Wang, Tao); He, K (He, Kai); Zhang, CM (Zhang, Chunmin); Zhang, J (Zhang, Jun); Chen, SR (Chen, Shaorong); Jia, H (Jia, Hui); Yuan, FF (Yuan, Fenfang); Liang, LL (Liang, Lingliang); Yan, X (Yan, Xin); Li, SH (Li, Shaohui); Wang, C (Wang, Chao); Yin, F (Yin, Fei)
来源出版物: PHYSICS LETTERS A 卷: 381 期: 41 页: 3594-3598 DOI: 10.1016/j.physleta.2017.08.064 出版年: NOV 5 2017
摘要: We report and experimentally demonstrate an ultrafast all-optical imaging technique capable of single shot ultrafast recording with a picosecond-scale temporal resolution and a micron-order two-dimensional spatial resolution. A GaAs/AlxGa1-xAs multiple-quantum-well (MQW) semiconductor with a picosecond response time, grown using molecular beam epitaxy (MBE) at a low temperature (LT), is used for the first time in ultrafast imaging technology. The semiconductor transforms the signal beam information to the probe beam, the birefringent delay crystal time-serializes the input probe beam, and the beam displacer maps different polarization probe beams onto different detector locations, resulting in two frames with an approximately 9 ps temporal separation and approximately 25 Ipimm spatial resolution in the visible range. (C) 2017 Elsevier B.V. All rights reserved.
入藏号: WOS:000413383400013
ISSN: 0375-9601
eISSN: 1873-2429
第 9 条,共 255 条
标题: Wavelength-tunable passively mode-locked mid-infrared Er3+-doped ZBLAN fiber laser
作者: Shen, YL (Shen, Yanlong); Wang, YS (Wang, Yishan); Chen, HW (Chen, Hongwei); Luan, KP (Luan, Kunpeng); Tao, MM (Tao, Mengmeng); Si, JH (Si, Jinhai)
来源出版物: SCIENTIFIC REPORTS 卷: 7 文献号: 14913 DOI: 10.1038/s41598-017-13089-6 出版年: NOV 2 2017
摘要: A passively mode-locked Er3+-doped ZBLAN fiber laser around 3 mu m with a wide wavelength tuning range is proposed and demonstrated. The laser cavity was comprised of a semiconductor saturable absorber mirror and a blazed grating to provide a wavelength tunable feedback. The central wavelength of the mode-locked fiber laser can be continuously tuned from 2710 to 2820 nm. The pulse train had a maximum average power of higher than 203 mW, a repetition rate of 28.9 MHz and a pulse duration of 6.4 ps, yielding a peak power of exceeding 1.1 kW. To the best of our knowledge, this is the first demonstration of a wavelength-tunable passively mode-locked mid-infrared fiber laser at 3 mu m.
入藏号: WOS:000414261500030
PubMed ID: 29097806
ISSN: 2045-2322
第 10 条,共 255 条
标题: Statistical Hypothesis Detector for Abnormal Event Detection in Crowded Scenes
作者: Yuan, Y (Yuan, Yuan); Feng, YC (Feng, Yachuang); Lu, XQ (Lu, Xiaoqiang)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 47 期: 11 页: 3597-3608 DOI: 10.1109/TCYB.2016.2572609 出版年: NOV 2017
摘要: Abnormal event detection is now a challenging task, especially for crowded scenes. Many existing methods learn a normal event model in the training phase, and events which cannot be well represented are treated as abnormalities. However, they fail to make use of abnormal event patterns, which are elements to comprise abnormal events. Moreover, normal patterns in testing videos may be divergent from training ones, due to the existence of abnormalities. To address these problems, in this paper, an abnormality detector is proposed to detect abnormal events based on a statistical hypothesis test. The proposed detector treats each sample as a combination of a set of event patterns. Due to the unavailability of labeled abnormalities for training, abnormal patterns are adaptively extracted from incoming unlabeled testing samples. Contributions of this paper are listed as follows: 1) we introduce the idea of a statistical hypothesis test into the framework of abnormality detection, and abnormal events are identified as ones containing abnormal event patterns while possessing high abnormality detector scores; 2) due to the complexity of video events, noise seldom follows a simple distribution. For this reason, we approximate the complex noise distribution by employing a mixture of Gaussian. This benefits the modeling of video events and improves abnormality detection accuracies; and 3) because of the existence of abnormalities, there are always some unusually occurring normal events in the testing videos, which differ from the training ones. To represent normal events precisely, an online updating strategy is proposed to cover these cases in the normal event patterns. As a result, false detections are eliminated mostly. Extensive experiments and comparisons with state-of-the-art methods verify the effectiveness of the proposed algorithm.
入藏号: WOS:000413003100010
PubMed ID: 27323389
作者识别号:
作者        ResearcherID 号        ORCID 号
Lu, Xiaoqiang                  0000-0002-7037-5188
ISSN: 2168-2267
eISSN: 2168-2275
第 11 条,共 255 条
标题: Graph Regularized Non-Negative Low-Rank Matrix Factorization for Image Clustering
作者: Li, XL (Li, Xuelong); Cui, GS (Cui, Guosheng); Dong, YS (Dong, Yongsheng)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 47 期: 11 页: 3840-3853 DOI: 10.1109/TCYB.2016.2585355 出版年: NOV 2017
摘要: Non-negative matrix factorization (NMF) has been one of the most popular methods for feature learning in the field of machine learning and computer vision. Most existing works directly apply NMF on high-dimensional image datasets for computing the effective representation of the raw images. However, in fact, the common essential information of a given class of images is hidden in their low rank parts. For obtaining an effective low-rank data representation, we in this paper propose a non-negative low-rank matrix factorization (NLMF) method for image clustering. For the purpose of improving its robustness for the data in a manifold structure, we further propose a graph regularized NLMF by incorporating the manifold structure information into our proposed objective function. Finally, we develop an efficient alternating iterative algorithm to learn the low-dimensional representation of low-rank parts of images for clustering. Alternatively, we also incorporate robust principal component analysis into our proposed scheme. Experimental results on four image datasets reveal that our proposed methods outperform four representative methods.
入藏号: WOS:000413003100029
PubMed ID: 27448379
ISSN: 2168-2267
eISSN: 2168-2275
第 12 条,共 255 条
标题: Nuclear Norm-Based 2DLPP for Image Classification
作者: Lu, YW (Lu, Yuwu); Yuan, C (Yuan, Chun); Lai, ZH (Lai, Zhihui); Li, XL (Li, Xuelong); Wong, WK (Wong, Wai Keung); Zhang, D (Zhang, David)
来源出版物: IEEE TRANSACTIONS ON MULTIMEDIA 卷: 19 期: 11 页: 2391-2403 DOI: 10.1109/TMM.2017.2703130 出版年: NOV 2017
摘要: Two-dimensional locality preserving projections (2DLPP) that use 2D image representation in preserving projection learning can preserve the intrinsic manifold structure and local information of data. However, 2DLPP is based on the Euclidean distance, which is sensitive to noise and outliers in data. In this paper, we propose a novel locality preserving projection method called nuclear norm-based two-dimensional locality preserving projections (NN-2DLPP). First, NN-2DLPP recovers the noisy data matrix through low-rank learning. Second, noise in data is removed and the learned clean data points are projected on a new subspace. Without the disturbance of noise, data points belonging to the same class are kept as close to each other as possible in the new projective subspace. Experimental results on six public image databases with face recognition, object classification, and handwritten digit recognition tasks demonstrated the effectiveness of the proposed method.
入藏号: WOS:000413068200003
ISSN: 1520-9210
eISSN: 1941-0077
第 13 条,共 255 条
标题: Regularized Class-Specific Subspace Classifier
作者: Zhang, R (Zhang, Rui); Nie, FP (Nie, Feiping); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 28 期: 11 页: 2738-2747 DOI: 10.1109/TNNLS.2016.2598744 出版年: NOV 2017
摘要: In this paper, we mainly focus on how to achieve the translated subspace representation for each class, which could simultaneously indicate the distribution of the associated class and the differences from its complementary classes. By virtue of the reconstruction problem, the class-specific subspace classifier (CSSC) problem could be represented as a series of biobjective optimization problems, which minimize and maximize the reconstruction errors of the related class and its complementary classes, respectively. Besides, the regularization term is specifically introduced to ensure the whole system's stability. Accordingly, a regularized class-specific subspace classifier (RCSSC) method can be further proposed based on solving a general quadratic ratio problem. The proposed RCSSC method consistently converges to the global optimal subspace and translation under the variations of the regularization parameter. Furthermore, the proposed RCSSC method could be extended to the unregularized case, which is known as unregularized CSSC (UCSSC) method via orthogonal decomposition technique. As a result, the effectiveness and the superiority of both proposed RCSSC and UCSSC methods can be verified analytically and experimentally.
入藏号: WOS:000413403900023
PubMed ID: 28113607
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhang, Rui         U-4639-2017         0000-0001-9418-0863
Nie, Feiping                  0000-0002-0871-6519
ISSN: 2162-237X
eISSN: 2162-2388
第 14 条,共 255 条
标题: Person Re-identification by Multi-hypergraph Fusion
作者: An, L (An, Le); Chen, XJ (Chen, Xiaojing); Yang, SF (Yang, Songfan); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 28 期: 11 页: 2763-2774 DOI: 10.1109/TNNLS.2016.2602082 出版年: NOV 2017
摘要: Matching people across nonoverlapping cameras, also known as person re-identification, is an important and challenging research topic. Despite its great demand in many crucial applications such as surveillance, person re-identification is still far from being solved. Due to drastic view changes, even the same person may look quite dissimilar in different cameras. Illumination and pose variations further aggravate this discrepancy. To this end, various feature descriptors have been designed for improving the matching accuracy. Since different features encode information from different aspects, in this paper, we propose to effectively leverage multiple off-the-shelf features via multi-hypergraph fusion. A hypergraph captures not only pairwise but also high-order relationships among the subjects being matched. In addition, different from conventional approaches in which the matching is achieved by computing the pairwise distance or similarity between a probe and a gallery subject, the similarities between the probe and all gallery subjects are learned jointly via hypergraph optimization. Experiments on popular data sets demonstrate the effectiveness of the proposed method, and a superior performance is achieved as compared with the most recent state-of-the-arts.
入藏号: WOS:000413403900025
PubMed ID: 28113383
ISSN: 2162-237X
eISSN: 2162-2388
第 15 条,共 255 条
标题: Chemical and spectroscopic investigations of K-H3O-Na jarosite solid solutions applicable for Mars explorations
作者: Cao, FK (Cao, Fengke); Ling, ZC (Ling, Zongcheng); Ni, YH (Ni, Yuheng)
来源出版物: JOURNAL OF RAMAN SPECTROSCOPY 卷: 48 期: 11 特刊: SI 页: 1544-1553 DOI: 10.1002/jrs.5222 出版年: NOV 2017
摘要: Jarosite is the first definitely discovered ferric sulfate mineral on Mars, indicating a highly acidic environment in Martian history. K-H3O and Na-H3O jarosite solid solutions were synthesized under hydrothermal conditions. Phase identifications and chemical compositions were determined by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy. Raman spectra of those two series of jarosite solid solutions show systematic spectral changes with varying alkali content. When chemical ratios of K/(K+H3O), in K-H3O jarosite solid solutions, increase from 0% to 88%, their Raman peaks exhibit systematic shifts: (2)(SO4)(2-) (from 424.7 to 434.3cm(-1)), (4)(SO4)(2-) (from 619.6 to 623.8cm(-1)), (1)(SO4)(2-) (from 1,011.8 to 1,006.1cm(-1)) and, (3)(SO4)(2-) (from 1,165.4 to 1,152.9cm(-1)). Near-infrared and mid-infrared spectra were also collected for the spectral library of Mars remote-sensing studies. The detailed chemical and spectroscopic studies of K-H3O-Na jarosite solid solutions would contribute to their potential discoveries on Mars by future Mars missions (e.g., Mars 2020 and ExoMars). Copyright (c) 2017 John Wiley & Sons, Ltd.
入藏号: WOS:000416235800023
ISSN: 0377-0486
eISSN: 1097-4555
第 16 条,共 255 条
标题: Patch-based topic model for group detection
作者: Chen, ML (Chen, Mulin); Wang, Q (Wang, Qi); Li, XL (Li, Xuelong)
来源出版物: SCIENCE CHINA-INFORMATION SCIENCES 卷: 60 期: 11 文献号: 113101 DOI: 10.1007/s11432-017-9237-1 出版年: NOV 2017
摘要: Pedestrians in crowd scenes tend to connect with each other and form coherent groups. In order to investigate the collective behaviors in crowds, plenty of studies have been conducted on group detection. However, most of the existing methods are limited to discover the underlying semantic priors of individuals. By segmenting the crowd image into patches, this paper proposes the Patch-based Topic Model (PTM) for group detection. The main contributions of this study are threefold: (1) the crowd dynamics are represented by patch-level descriptor, which provides a macroscopic-level representation; (2) the semantic topic label of each patch are inferred by integrating the Latent Dirichlet Allocation (LDA) model and the Markov Random Fields (MRF); (3) the optimal group number is determined automatically with an intro-class distance evaluation criterion. Experimental results on real-world crowd videos demonstrate the superior performance of the proposed method over the state-of-the-arts.
入藏号: WOS:000415021600009
ISSN: 1674-733X
eISSN: 1869-1919
第 17 条,共 255 条
标题: Locality Adaptive Discriminant Analysis for Spectral-Spatial Classification of Hyperspectral Images
作者: Wang, Q (Wang, Qi); Meng, ZT (Meng, Zhaotie); Li, XL (Li, Xuelong)
来源出版物: IEEE GEOSCIENCE AND REMOTE SENSING LETTERS 卷: 14 期: 11 页: 2077-2081 DOI: 10.1109/LGRS.2017.2751559 出版年: NOV 2017
摘要: Linear discriminant analysis (LDA) is a popular technique for supervised dimensionality reduction, but with less concern about a local data structure. This makes LDA inapplicable to many real-world situations, such as hyperspectral image (HSI) classification. In this letter, we propose a novel dimensionality reduction algorithm, locality adaptive discriminant analysis (LADA) for HSI classification. The proposed algorithm aims to learn a representative subspace of data, and focuses on the data points with close relationship in spectral and spatial domains. An intuitive motivation is that data points of the same class have similar spectral feature and the data points among spatial neighborhood are usually associated with the same class. Compared with traditional LDA and its variants, LADA is able to adaptively exploit the local manifold structure of data. Experiments carried out on several real hyperspectral data sets demonstrate the effectiveness of the proposed method.
入藏号: WOS:000413955500040
作者识别号:
作者        ResearcherID 号        ORCID 号
Wang, Qi                  0000-0002-7028-4956
ISSN: 1545-598X
eISSN: 1558-0571
第 18 条,共 255 条
标题: Effects of doping SiO2 on the defect's change in B2O3-containing phosphate based laser glasses used for high energy UV lasers
作者: Sun, MY (Sun, Mengya); Duan, ZJ (Duan, Zhanjun); Wang, PF (Wang, Pengfei); Lu, M (Lu, Min); Peng, B (Peng, Bo)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 7 期: 11 页: 4111-4122 DOI: 10.1364/OME.7.004111 出版年: NOV 1 2017
摘要: The introduction of SiO2 affects the glass's micro-structure and micro-defects as well as the corresponding optical and physical properties of the B2O3-containing multicomponent phosphate glasses. The addition of SiO2 increases the transition temperature and causes shifts of the UV cut-off wavelength (lambda(cut-off)). The changes of lambda(cut-off) are closely related to the PO3-EC and PO4-EC defect centers that are associated with the Q(2) tetrahedral in phosphate chains. The corresponding variations of Q(2) units can also be found in the Raman, XPS, and P-31 MAS-NMR spectra. With increasing the content of SiO2, the ratio of nonbridging oxygen (associated with Q(2) units) is gradually decreased down to a critical level when SiO2/B2O3 ratio is 4/1.5, whereas the ratio of non-bridging oxygen increases when SiO2/B2O3 ratio is larger than 4/1.5, which suggests that the doping SiO2 can influence the concentration of PO3-EC and PO4-EC defects. Those results can be better obtained when the sample is exposed to gamma irradiation. As the SiO2 content increased gradually up to 4/1.5, the concentration of the PO3-EC defects declined, while the concentration of PO4-EC and the POHC defects increased when considering the irradiation dose, indicating that the addition of SiO2 can regulate the structure-related defects in phosphate based glasses. (C) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
入藏号: WOS:000414248700030
ISSN: 2159-3930
第 19 条,共 255 条
标题: Multichannel phase-sensitive amplification in a low-loss CMOS-compatible spiral waveguide
作者: Zhang, YB (Zhang, Yanbing); Reimer, C (Reimer, Christian); Wu, J (Wu, Jenny); Roztocki, P (Roztocki, Piotr); Wetzel, B (Wetzel, Benjamin); Little, BE (Little, Brent E.); Chu, ST (Chu, Sai T.); Moss, DJ (Moss, David J.); Eggleton, BJ (Eggleton, Benjamin J.); Kues, M (Kues, Michael); Morandotti, R (Morandotti, Roberto)
来源出版物: OPTICS LETTERS 卷: 42 期: 21 页: 4391-4394 DOI: 10.1364/OL.42.004391 出版年: NOV 1 2017
摘要: We investigate single-channel and multichannel phase-sensitive amplification (PSA) in a highly nonlinear, CMOS-compatible spiral waveguide with ultralow linear and negligible nonlinear losses. We achieve a net gain of 10.4 dB and an extinction ratio of 24.6 dB for single-channel operation, as well as a 5 dB gain and a 15 dB extinction ratio spanning over a bandwidth of 24 nm for multiple-channel operation. In addition, we derive a simple analytic solution that enables calculating the maximum phase-sensitive gain in any Kerr medium featuring linear and nonlinear losses. These results not only give a clear guideline for designing PSA-based amplifiers but also show that it is possible to implement both optical regeneration and amplification in a single on-chip device. (C) 2017 Optical Society of America
入藏号: WOS:000414097200039
PubMed ID: 29088171
作者识别号:
作者        ResearcherID 号        ORCID 号
moss, david                  0000-0001-5195-1744
CHU, Sai Tak                  0000-0001-8263-8507
ISSN: 0146-9592
eISSN: 1539-4794
第 20 条,共 255 条
标题: Roles of palladium particles in enhancing the electrochemical migration resistance of sintered nano-silver paste as a bonding material
作者: Wang, D (Wang, Di); Mei, YH (Mei, Yun-Hui); Xie, HN (Xie, Haining); Zhang, K (Zhang, Kun); Siow, KS (Siow, Kim S.); Li, X (Li, Xin); Lu, GQ (Lu, Guo-Quan)
来源出版物: MATERIALS LETTERS 卷: 206 页: 1-4 DOI: 10.1016/j.matlet.2017.06.066 出版年: NOV 1 2017
摘要: The inhibition effect and mechanism of adding palladium particles to nano-silver paste on the migration of silver in high temperature is reported. The electrochemical migration (ECM) tests showed that silver migration was significantly delayed by the addition of palladium. The roles of different compositions, e.g., PdO, in enhancing the ECM resistance of silver were studied experimentally. We found Ag-Pd alloy < PdO < PdO (the oxidation process of palladium). The oxidation of palladium to palladium (II) oxides (PdO) suppressed the silver oxides to delay the onset of silver dendrites formation resulting in longer failure lifetime than the pure PdO, Ag-Pd alloy or a simple combination of the two. (C) 2017 Elsevier B.V. All rights reserved.
入藏号: WOS:000407407300001
作者识别号:
作者        ResearcherID 号        ORCID 号
Siow, Kim         A-1408-2008         0000-0003-2519-780X
ISSN: 0167-577X
eISSN: 1873-4979
第 21 条,共 255 条
标题: A generalized power iteration method for solving quadratic problem on the Stiefel manifold
作者: Nie, FP (Nie, Feiping); Zhang, R (Zhang, Rui); Li, XL (Li, Xuelong)
来源出版物: SCIENCE CHINA-INFORMATION SCIENCES 卷: 60 期: 11 文献号: 112101 DOI: 10.1007/s11432-016-9021-9 出版年: NOV 2017
摘要: In this paper, we first propose a novel generalized power iteration (GPI) method to solve the quadratic problem on the Stiefel manifold (QPSM) as min(W)(W)(T)=I Tr(W(T)AW - 2W(T)B) along with the theoretical analysis. Accordingly, its special case known as the orthogonal least square regression (OLSR) is under further investigation. Based on the aforementioned studies, we then majorly focus on solving the unbalanced orthogonal procrustes problem (UOPP). As a result, not only a general convergent algorithm is derived theoretically but the efficiency of the proposed approach is verified empirically as well.
入藏号: WOS:000405777400005
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhang, Rui         U-4639-2017         0000-0001-9418-0863
ISSN: 1674-733X
eISSN: 1869-1919
第 22 条,共 255 条
标题: Wavelength-switchable passively mode-locked fiber laser with mechanically exfoliated molybdenum ditelluride on side-polished fiber
作者: Wang, GM (Wang, Guomei)
来源出版物: OPTICS AND LASER TECHNOLOGY 卷: 96 页: 307-312 DOI: 10.1016/j.optlastec.2017.05.030 出版年: NOV 1 2017
摘要: We experimentally investigated the nonlinear saturable absorption characteristics of molybdenum ditelluride (MoTe2) and demonstrated a wavelength-switchable mode-locked erbium-doped fiber laser (EDFL) by using MoTe2 thin film on side-polished fiber (SPF) as saturable absorber. Here, the MoTe2 thin film was efficiently fabricated via mechanical exfoliation method and transferred onto the SPF with the assistance of polydimethylsiloxane (PDMS). MoTe2-covered SPF (MSPF) exhibits the nonlinear saturable absorption for pulses with different polarization states. Optical solitons with spectral bandwidth of 1.06 (1.31) nm centered at similar to 1559 (similar to 1528) nm and pulse duration of 2.46 (2.04) ps can be obtained from the EDFL by adjusting the polarization controller (PC) properly. The time-bandwidth product (TBP) of the pulses was calculated as 0.322 (0.344). (C) 2017 Elsevier Ltd. All rights reserved.
入藏号: WOS:000405051800043
ISSN: 0030-3992
eISSN: 1879-2545
第 23 条,共 255 条
标题: Frequency-degenerate parametric generation through IFWM effect in nanowaveguides
作者: Liu, ML (Liu, Mulong); Wang, LR (Wang, Leiran); Sun, QB (Sun, Qibing); Wang, WQ (Wang, Weiqiang); Wang, GX (Wang, Guoxi); Li, SQ (Li, Siqi); Zhang, LX (Zhang, Lingxuan); Zhang, WF (Zhang, Wenfu); Hu, XH (Hu, Xiaohong); Gong, YK (Gong, Yongkang); Zhao, W (Zhao, Wei)
来源出版物: MODERN PHYSICS LETTERS B 卷: 31 期: 29 文献号: 1750266 DOI: 10.1142/S0217984917502669 出版年: OCT 20 2017
摘要: We investigate highly efficient frequency-degenerate parametric generation through inverse four-wave-mixing (IFWM) in silicon nanowaveguides, which exhibits distinctly from traditional FWM phenomenon and manifests itself as a unique process producing signal and idler photon pairs with frequencies at the center of two pumps. The influences of dispersion, nonlinear coefficient and frequency detuning on the IFWM process are numerically analyzed in detail. On this basis, the optimal condition for high gain IFWM and the nanowaveguide with high nonlinearity and large normal dispersion are proposed. These results substantiate the feasibility of such frequency-degenerate parametric generation in CMOS-compatible integrated platforms, which could find important potential in signal-processing systems for photonics networks and entangled qubits generation for quantum optics.
入藏号: WOS:000413152400005
ISSN: 0217-9849
eISSN: 1793-6640
第 24 条,共 255 条
标题: Eight-wave mixing parametrical amplification
作者: Liu, Y (Liu, Yang); Li, KK (Li, Kangkang); Liu, YZ (Liu, Yize); Yang, GG (Yang, Gaoguo); Wang, K (Wang, Kun); Zhang, YP (Zhang, Yanpeng)
来源出版物: OPTICS EXPRESS 卷: 25 期: 21 页: 25212-25221 DOI: 10.1364/OE.25.025212 出版年: OCT 16 2017
摘要: We investigate parametrically amplified eight-wave mixing (PA-EWM). The double dressed PA-four-wave mixing (PA-FWM) is the superposition of one PA-FWM process, two different PA-six-wave mixing (PA-SWM) processes (PA-SWM1 and PA-SWM2 with external dressing field 776nm and 795nm, respectively) and one PA-EWM process. When the phases among FWM, SWM1, SWM2 and EWM change from 0 to pi, the double dressed PA-FWM could gradually satisfy the pure enhancement (all 0), partial enhancement and suppression (mixture of 0 and pi), or pure suppression condition (all pi). The outcomes of the investigation can potentially contribute to the development of multi-channel quantum information processing and high dimensional stereoscopic imaging. (C) 2017 Optical Society of America
入藏号: WOS:000413103300034
PubMed ID: 29041191
ISSN: 1094-4087
第 25 条,共 255 条
标题: Temperature-calibrated high-precision refractometer using a tilted fiber Bragg grating
作者: Jiang, BQ (Jiang, Biqiang); Zhou, KM (Zhou, Kaiming); Wang, CL (Wang, Changle); Zhao, YH (Zhao, Yunhe); Zhao, JL (Zhao, Jianlin); Zhang, L (Zhang, Lin)
来源出版物: OPTICS EXPRESS 卷: 25 期: 21 页: 25910-25918 DOI: 10.1364/OE.25.025910 出版年: OCT 16 2017
摘要: We present a refractometer with main-and vernier-scale to measure the refractive index (RI) of liquids with high precision by using the fine spectrum structure of a tilted fiber Bragg grating (TFBG). The absolute RI values are determined by the accurate wavelength of cut-off mode resonances. The main-and vernier-scale are calibrated by measuring large groups of fine spectra at different cut-off mode resonances in a small RI range, and the use of vernier-scale certainly reduces the RI measurement uncertainty resulted from the discrete cladding mode resonances. The performance of the TFBG-based vernier refractometer is experimentally verified by exploring the temperature dependence of RI of anhydrous ethanol in a near infrared region, showing an enhanced accuracy to the order of 10(-4), high repeatability and temperature self-calibration capability. (c) 2017 Optical Society of America
入藏号: WOS:000413103300096
PubMed ID: 29041253
ISSN: 1094-4087
第 26 条,共 255 条
标题: Graphene oxide-COOH as a new saturable absorber for both Q-switching and mode-locking fiber lasers
作者: Zhao, FY (Zhao, Fengyan); Wang, YS (Wang, Yishan); Wang, YG (Wang, Yonggang); Wang, HS (Wang, Hushan); Cai, YJ (Cai, Yajun)
来源出版物: CHINESE OPTICS LETTERS 卷: 15 期: 10 文献号: 101402 DOI: 10.3788/COL201715.101402 出版年: OCT 10 2017
摘要: Graphene oxide carboxylic acid (COOH), a novel two-dimensional (2D) layered material with its unique optical and electronic properties, is discovered to exhibit the saturation of optical absorption under laser illumination. Applying the liquid-phase exfoliation method, we prepare graphene oxide-COOH dispersions with deionized water and fabricate graphene oxide-COOH polyvinyl alcohol polymer composite film. We further obtain stable Q-switching pulse and mode-locked laser operation with a 22.7MHz repetition rate and a 1.5 ps pulse duration by incorporating the graphene oxide-COOH-based saturable absorbers into the all-fiber erbium-doped fiber laser cavity. The experimental results show that the proposed graphene oxide-COOH material can act as an effective absorber for pulsed fiber lasers, which demonstrate potential applications in the area of ultrafast optics.
入藏号: WOS:000412692400017
ISSN: 1671-7694
第 27 条,共 255 条
标题: Structural evolution study of additions of Sb2S3 and CdS into GeS2 chalcogenide glass by Raman spectroscopy
作者: Guo, HT (Guo, Hai-Tao); Zhang, MJ (Zhang, Ming-Jie); Xu, YT (Xu, Yan-Tao); Xiao, XS (Xiao, Xu-Sheng); Yang, ZY (Yang, Zhi-Yong)
来源出版物: CHINESE PHYSICS B 卷: 26 期: 10 文献号: 104208 DOI: 10.1088/1674-1056/26/10/104208 出版年: OCT 2017
摘要: The structures of pseudo-binary GeS2-Sb2S3, GeS2-CdS, Sb2S3-CdS, and pseudo-ternary GeS2-Sb2S3-CdS chalcogenide systems are systematically investigated by Raman spectroscopy. It is shown that a small number of [S3Ge-GeS3] structural units (SUs) and -S-S-/S-8 groups exist simultaneously in GeS2 glass which has a three-dimensional continuous network backbone consisting of cross-linked corner-sharing and edge-sharing [GeS4] tetrahedra. When Sb2S3 is added into GeS2 glass, the network backbone becomes interconnected [GeS4] tetrahedra and [SbS3] pyramids. Moreover, Ge atoms in [S3Ge-GeS3] SUs tend to capture S atoms from Sb2S3, leading to the formation of [S2Sb-SbS2] SUs. When CdS is added into GeS2 glass, [Cd4GeS6] polyhedra are formed, resulting in a strong crystallization tendency. In addition, Ge atoms in [S3Ge-GeS3] SUs tend to capture S atoms from CdS, resulting in the dissolution of Ge-Ge bond. Co-melting of Sb2S3 or CdS with GeS2 reduces the viscosity of the melt and improves the homogeneity of the glass. The GeS2 glass can only dissolve up to 10-mol% CdS without crystallization. In comparison, GeS2-Sb2S3 glasses can dissolve up to 20-mol% CdS, implying that Sb2S3 could delay the construction of [Cd4GeS6] polyhedron and increase the dissolving amount of CdS in the glass.
入藏号: WOS:000412420300002
ISSN: 1674-1056
eISSN: 1741-4199
第 28 条,共 255 条
标题: Nested grazing incidence optics for x ray detection
作者: Li, LS (Li, Lin-Sen); Qiang, PF (Qiang, Peng-Fei); Sheng, LZ (Sheng, Li-Zhi); Liu, YA (Liu, Yong-An); Liu, Z (Liu, Zhe); Liu, D (Liu, Duo); Zhao, BS (Zhao, Bao-Sheng); Zhang, CM (Zhang, Chun-Min)
来源出版物: CHINESE PHYSICS B 卷: 26 期: 10 文献号: 100703 DOI: 10.1088/1674-1056/26/10/100703 出版年: OCT 2017
摘要: Grazing incidence optics (GIO) is the most important compound in an x-ray detection system; it is used to concentrate the x-ray photons from outer space. A nested planar GIO for x-ray concentration is designed and developed by authors in this paper; planar segments are used as the reflection mirror instead of curved segments because of the simple process and low cost. After the complex assembling process with a special metal supporter, a final circle light spot of phi 12 mm was obtained in the visible light testing experiment of GIO; the effective area of 1710.51 mm(2)@ 1 keV and 530 mm2@ 8 keV is obtained in the x-ray testing experiment with the GIO-SDD combination, which is supposed to be a concentrating detector in xray detection systems.
入藏号: WOS:000412331800003
ISSN: 1674-1056
eISSN: 1741-4199
第 29 条,共 255 条
标题: An Efficient Contrast Enhancement Method for Remote Sensing Images
作者: Liu, JH (Liu, Jiahang); Zhou, CH (Zhou, Chenghu); Chen, P (Chen, Peng); Kang, CM (Kang, Chaomeng)
来源出版物: IEEE GEOSCIENCE AND REMOTE SENSING LETTERS 卷: 14 期: 10 页: 1715-1719 DOI: 10.1109/LGRS.2017.2730247 出版年: OCT 2017
摘要: Remote sensing images often suffer low contrast. Although many contrast enhancement methods have been proposed in recent literature, the efficiency and robustness of remote sensing image contrast enhancement is still a challenge. In this letter, a novel self-adaptive histogram compacting transform-based contrast enhancement method for remote sensing images is presented to meet with the requirements of automation, robustness, and efficiency in applications. First, the histogram of an input image is optimized into compact and continuous status with the constraints of the merging cost, the moderate global brightness, and the entropy contribution of gray levels. Then, a local remapping algorithm is proposed to catch more details during the course of gray extending with the linear stretch. Finally, a dual-gamma transform is proposed to enhance the contrast in both bright and black areas. Experimental and comparison results demonstrate that the proposed method yields better results than the state-of-the-art methods and maintains robustness in different cases. It provides an effective approach for remote sensing image automatic contrast enhancement.
入藏号: WOS:000413961200014
ISSN: 1545-598X
eISSN: 1558-0571
第 30 条,共 255 条
标题: Adaptive Multimedia Data Forwarding for Privacy Preservation in Vehicular Ad-Hoc Networks
作者: Xia, YJ (Xia, Yingjie); Chen, WZ (Chen, Wenzhi); Liu, XJ (Liu, Xuejiao); Zhang, LM (Zhang, Luming); Li, XL (Li, Xuelong); Xiang, Y (Xiang, Yang)
来源出版物: IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS 卷: 18 期: 10 页: 2629-2641 DOI: 10.1109/TITS.2017.2653103 出版年: OCT 2017
摘要: Vehicular ad-hoc networks (VANETs) have drawn much attention of researchers. The vehicles in VANETs frequently join and leave the networks, and therefore restructure the network dynamically and automatically. Forwarded messages in vehicular ad-hoc networks are primarily multimedia data, including structured data, plain text, sound, and video, which require access control with efficient privacy preservation. Ciphertext-policy attribute-based encryption (CP-ABE) is adopted to meet the requirements. However, solutions based on traditional CP-ABE suffer from challenges of the limited computational resources on-board units equipped in the vehicles, especially for the complex policies of encryption and decryption. In this paper, we propose a CP-ABE delegation scheme, which allows road side units (RSUs) to perform most of the computation, for the purpose of improving the decryption efficiency of the vehicles. By using decision tree to jointly optimize multiple factors, such as the distance from RSU, the communication and computational cost, the CP-ABE delegation scheme is adaptively activated based on the estimation of various vehicles decryption overhead. Experimental results thoroughly demonstrate that our scheme is effective and efficient for multimedia data forwarding in vehicular ad-hoc networks with privacy preservation.
入藏号: WOS:000412223300005
ISSN: 1524-9050
eISSN: 1558-0016
第 31 条,共 255 条
标题: Characteristics of the spectral lines of immersion gratings
作者: Tang, Q (Tang Qian); Guo, LX (Guo Li-Xin); Zhao, BC (Zhao Bao-Chang)
来源出版物: JOURNAL OF INFRARED AND MILLIMETER WAVES 卷: 36 期: 5 页: 569-574 DOI: 10.11972/j.issn.1001-9014.2017.05.010 出版年: OCT 2017
摘要: Immersion gratings are typically used in the infrared spectral band in which optical materials with high refractive index. Some issues inevitably arise due to their special operating mode. And they are critical to the application of immersion gratings. This study investigated the relations between the lengths of the long- and short-wave of normal gratings. For the features of the relevance of the refractive index with wavelength, the short-wave infrared spectral band (1.5 similar to 2.5 mu m) was taken as an example to analyze the change characteristics of spectral line location and spectral resolution of immersion gratings. Results showed that when immersion gratings were adopted, significant differences were observed in the distribution of spectral lines as compared with normal gratings, and "trapezoidal" spectral lines tilted. For short-wave infrared spectral lines, the inclination of the "trapezoidal" spectral lines became more apparent due to larger changes in the refractive index of the medium. When Littrow conditions were registered with long-wave length (2. 5 mu m), the spectral line tilted toward the short-wave end. When registration was done with short-wave length (1. 5 mu m), the spectral line tilted toward the long-wave end, and the Littrow wavelength drifted away from, the central wavelength. The refractive index had a few changes at the thermal infrared spectral band. The tilt of "trapezoidal" spectral lines was smaller and more similar to that of normal gratings. The spectral resolution of immersion gratings varied due to changes in the refractive index. At the same order, the wavelength increased, and resolution increased; between various orders, the order decreased, and the resolution decreased. Meanwhile, considering that the high-order resolution was larger than the low-order' s, the ratio of the lengths of spectral lines at various orders no longer meet the relation of normal gratings.
入藏号: WOS:000416193300010
ISSN: 1001-9014
第 32 条,共 255 条
标题: Refined-Graph Regularization-Based Nonnegative Matrix Factorization
作者: Li, XL (Li, Xuelong); Cui, GS (Cui, Guosheng); Dong, YS (Dong, Yongsheng)
来源出版物: ACM TRANSACTIONS ON INTELLIGENT SYSTEMS AND TECHNOLOGY 卷: 9 期: 1 文献号: 1 DOI: 10.1145/3090312 出版年: OCT 2017
摘要: Nonnegative matrix factorization (NMF) is one of the most popular data representation methods in the field of computer vision and pattern recognition. High-dimension data are usually assumed to be sampled fromthe submanifold embedded in the original high-dimension space. To preserve the locality geometric structure of the data, k-nearest neighbor (k-NN) graph is often constructed to encode the near-neighbor layout structure. However, k-NN graph is based on Euclidean distance, which is sensitive to noise and outliers. In this article, we propose a refined-graph regularized nonnegative matrix factorization by employing a manifold regularized least-squares regression (MRLSR) method to compute the refined graph. In particular, each sample is represented by the whole dataset regularized with l(2)-norm and Laplacian regularizer. Then a MRLSR graph is constructed based on the representative coefficients of each sample. Moreover, we present two optimization schemes to generate refined-graphs by employing a hard-thresholding technique. We further propose two refined-graph regularized nonnegative matrix factorization methods and use them to perform image clustering. Experimental results on several image datasets reveal that they outperform 11 representative methods.
入藏号: WOS:000414316900001
ISSN: 2157-6904
eISSN: 2157-6912
第 33 条,共 255 条
标题: Multifeature Anisotropic Orthogonal Gaussian Process for Automatic Age Estimation
作者: Li, ZF (Li, Zhifeng); Gong, DH (Gong, Dihong); Zhu, K (Zhu, Kai); Tao, DC (Tao, Dacheng); Li, XL (Li, Xuelong)
来源出版物: ACM TRANSACTIONS ON INTELLIGENT SYSTEMS AND TECHNOLOGY 卷: 9 期: 1 文献号: 2 DOI: 10.1145/3090311 出版年: OCT 2017
摘要: Automatic age estimation is an important yet challenging problem. It has many promising applications in social media. Of the existing age estimation algorithms, the personalized approaches are among the most popular ones. However, most person-specific approaches rely heavily on the availability of training images across different ages for a single subject, which is usually difficult to satisfy in practical application of age estimation. To address this limitation, we first propose a new model called Orthogonal Gaussian Process (OGP), which is not restricted by the number of training samples per person. In addition, without sacrifice of discriminative power, OGP is much more computationally efficient than the standard Gaussian Process. Based on OGP, we then develop an effective age estimation approach, namely anisotropic OGP (A-OGP), to further reduce the estimation error. A-OGP is based on an anisotropic noise level learning scheme that contributes to better age estimation performance. To finally optimize the performance of age estimation, we propose a multifeature A-OGP fusion framework that uses multiple features combined with a random sampling method in the feature space. Extensive experiments on several public domain face aging datasets (FG-NET, MORPH Album1, and MORPH Album 2) are conducted to demonstrate the state-of-the-art estimation accuracy of our new algorithms.
入藏号: WOS:000414316900002
ISSN: 2157-6904
eISSN: 2157-6912
第 34 条,共 255 条
标题: High-energy femtosecond fiber laser system and pulse selection based on high-repetition rate KTiOPO4 Pockels cell
作者: Li, F (Li, Feng); Yang, Z (Yang, Zhi); Lv, ZG (Lv, Zhiguo); Yang, Y (Yang, Yang); Zhu, WQ (Zhu, Wenqi); Jiang, BN (Jiang, Baoning); Li, QL (Li, Qianglong); Yang, XJ (Yang, Xiaojun); Wang, YS (Wang, Yishan); Zhao, W (Zhao, Wei)
来源出版物: OPTICAL ENGINEERING 卷: 56 期: 10 文献号: 106101 DOI: 10.1117/1.OE.56.10.106101 出版年: OCT 2017
摘要: A fiber chirped-pulse amplification system with pulse energy as high as 105 mu J is achieved at 200-kHz repetition rate using the rod-type photonic crystal fiber. The whole system's nonlinearity accumulated in the fiber amplification is effectively suppressed, and the compressed pulse duration of 808 fs is obtained. A 500-kHz high-repetition rate KTiOPO4 Pockels cell is also applied to make the ultrafast laser pulse selection for generating pulse trains with controllable pulse number and pulse splitting without changing the pulse energy. The demonstrated pulse selection and splitting method are useful for processing of different materials and parallel processing. The pulse selection efficiency of the Pockels cell is as high as 96%. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000414251700027
ISSN: 0091-3286
eISSN: 1560-2303
第 35 条,共 255 条
标题: Midinfrared wavelength conversion in hydrogenated amorphous silicon waveguides
作者: Wang, J (Wang, Jiang); Wang, ZL (Wang, Zhaolu); Huang, N (Huang, Nan); Han, J (Han, Jing); Li, YF (Li, Yongfang); Liu, HJ (Liu, Hongjun)
来源出版物: OPTICAL ENGINEERING 卷: 56 期: 10 文献号: 107103 DOI: 10.1117/1.OE.56.10.107103 出版年: OCT 2017
摘要: Midinfrared (MIR) wavelength conversion based on degenerate four-wave mixing is theoretically investigated in hydrogenated amorphous silicon (a-Si:H) waveguides. The broadband phase mismatch is achieved in the normal group-velocity dispersion regime. The conversion bandwidth is extended to 900 nm, and conversion efficiency of up to - 14 dB with a pump power of 70 mW in a 2-mm long a-Si:H rib waveguides is obtained. This low-power on-chip wavelength converter will have potential for application in a wide range of MIR nonlinear optic devices. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000414251700046
ISSN: 0091-3286
eISSN: 1560-2303
第 36 条,共 255 条
标题: Study of Ultraviolet Photon Counting Detector with Delay-Line Anode
作者: Lei, FP (Lei Fan-pu); Zhu, BL (Zhu Bing-li); Bai, XH (Bai Xiao-hong); Qin, JJ (Qin Jun-jun); Xu, P (Xu Peng); Hou, X (Hou Xun)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 37 期: 10 页: 2989-2994 DOI: 10.3964/j.issn.1000-0593(2017)10-2989-06 出版年: OCT 2017
摘要: Delay-line anode detector based on MCP electron multiplier detect the incident photon's location by the arrival time difference of the MCP output charge pulse at each end of delay line. Due to their high spatial resolution and high counting rate, photon counting detectors with delay line anode have been widely used in ultraviolet spectral imaging systems. Operational principle of ultraviolet photon detector based on delay line anode is analyzed, and a novel two-dimensional serpentine delay line anode is designed. Electron cloud output from MCP is collected only by the anode surface. The upper serpentine delay line receives the MCP output charge directly, while the lower serpentine delay line receives the charge using a series of pads and vias. This anode is made of printed circuit board instead of laser etching, which greatly simplifies the fabrication process. Photon counting detector with this type of anode achieves a 92 mu m FWHM resolution. And the image linearity is better than 100 mu m. The results of theory analysis and experiments demonstrated the feasibility of ultraviolet photon imaging system. It provides a theoretical basis and experiments guidance for the development of ultraviolet imaging spectrometers.
入藏号: WOS:000413888200001
ISSN: 1000-0593
第 37 条,共 255 条
标题: Research on Mural Painting Appreciatione Based on Spectral Imaging and Spectral Analysis
作者: Xu, WZ (Xu Wen-zhong); Tang, XJ (Tang Xing-jia); Zhang, G (Zhang Geng); Yang, FC (Yang Fan-chao); Huang, X (Huang Xing); Li, X (Li Xia); Liu, DY (Liu Dai-yun); Zhao, XC (Zhao Xi-Chen)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 37 期: 10 页: 3235-3241 DOI: 10.3964/j.issn.1000-0593(2017)10-3235-07 出版年: OCT 2017
摘要: For the technology requirements of appreciating mural paintings, according to the advantages of spectral imaging and spectral analysis, the usages of spectral imaging in appreciating mural paintings were discussed, which could improve the traditional expert experience identification method by providing more information in the appreciation and assessment. Spectral method is an important scientific analysis method with many characteristics, like non-contact, lossless, scientific, accurate and quantifiable, which can be used to appreciate mural paintings. Firstly, the application was analyzed from different functions. Secondly, the measurements of mural paintings in HAN XIU tomb were processed by spectral analysis, primary component analysis, independent component analysis, relevance judgment and interactive processing, which were for proving the real affection of the theory analysis. At last, based on the experiments, some key technologies were summarized, for example, normalized measurements, analysis of characters of image and spectral data, processer of image and spectral data. The experiment results showed that the spectral imaging and analysis were useful for the recognition of pigment, the extraction of hidden information, the enhancement of weak information, and the classification and recognition of different properties. Meanwhile, some exploratory works can be unfolded, like modified child analysis, repairing of paintings (such as repairing mural paintings in HAN XIU tomb).
入藏号: WOS:000413888200047
ISSN: 1000-0593
第 38 条,共 255 条
标题: A Biologically Inspired Appearance Model for Robust Visual Tracking
作者: Zhang, SP (Zhang, Shengping); Lan, XY (Lan, Xiangyuan); Yao, HX (Yao, Hongxun); Zhou, HY (Zhou, Huiyu); Tao, DC (Tao, Dacheng); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 28 期: 10 页: 2357-2370 DOI: 10.1109/TNNLS.2016.2586194 出版年: OCT 2017
摘要: In this paper, we propose a biologically inspired appearance model for robust visual tracking. Motivated in part by the success of the hierarchical organization of the primary visual cortex (area V1), we establish an architecture consisting of five layers: whitening, rectification, normalization, coding, and pooling. The first three layers stem from the models developed for object recognition. In this paper, our attention focuses on the coding and pooling layers. In particular, we use a discriminative sparse coding method in the coding layer along with spatial pyramid representation in the pooling layer, which makes it easier to distinguish the target to be tracked from its background in the presence of appearance variations. An extensive experimental study shows that the proposed method has higher tracking accuracy than several state-of-the-art trackers.
入藏号: WOS:000411293200012
PubMed ID: 27448375
作者识别号:
作者        ResearcherID 号        ORCID 号
Yan, Yong                  0000-0001-7135-5456
Zhang, Shuai                  0000-0002-9003-2879
ISSN: 2162-237X
eISSN: 2162-2388
第 39 条,共 255 条
标题: Remote Sensing Image Scene Classification: Benchmark and State of the Art
作者: Cheng, G (Cheng, Gong); Han, JW (Han, Junwei); Lu, XQ (Lu, Xiaoqiang)
来源出版物: PROCEEDINGS OF THE IEEE 卷: 105 期: 10 特刊: SI 页: 1865-1883 DOI: 10.1109/JPROC.2017.2675998 出版年: OCT 2017
摘要: Remote sensing image scene classification plays an important role in a wide range of applications and hence has been receiving remarkable attention. During the past years, significant efforts have been made to develop various data sets or present a variety of approaches for scene classification from remote sensing images. However, a systematic review of the literature concerning data sets and methods for scene classification is still lacking. In addition, almost all existing data sets have a number of limitations, including the small scale of scene classes and the image numbers, the lack of image variations and diversity, and the saturation of accuracy. These limitations severely limit the development of new approaches especially deep learning-based methods. This paper first provides a comprehensive review of the recent progress. Then, we propose a large-scale data set, termed "NWPU-RESISC45," which is a publicly available benchmark for REmote Sensing Image Scene Classification (RESISC), created by Northwestern Polytechnical University (NWPU). This data set contains 31 500 images, covering 45 scene classes with 700 images in each class. The proposed NWPU-RESISC45 1) is large-scale on the scene classes and the total image number; 2) holds big variations in translation, spatial resolution, viewpoint, object pose, illumination, background, and occlusion; and 3) has high within-class diversity and between-class similarity. The creation of this data set will enable the community to develop and evaluate various data-driven algorithms. Finally, several representative methods are evaluated using the proposed data set, and the results are reported as a useful baseline for future research.
入藏号: WOS:000411273300004
作者识别号:
作者        ResearcherID 号        ORCID 号
Lu, Xiaoqiang                  0000-0002-7037-5188
ISSN: 0018-9219
eISSN: 1558-2256
第 40 条,共 255 条
标题: On Combining Social Media and Spatial Technology for POI Cognition and Image Localization
作者: Qian, XM (Qian, Xueming); Lu, XQ (Lu, Xiaoqiang); Han, JW (Han, Junwei); Du, B (Du, Bo); Li, XL (Li, Xuelong)
来源出版物: PROCEEDINGS OF THE IEEE 卷: 105 期: 10 特刊: SI 页: 1937-1952 DOI: 10.1109/JPROC.2017.2731600 出版年: OCT 2017
摘要: With fast development of information engineering and social network, people's locations can be conveniently sensed by spatial technology, such as global positioning systems (GPS), base stations, Wi-Fi access points and even from the appearances of the photos they have taken. The social networks and the online shopping platforms have been gathering billions of users, who share a large amount of images taken in places they live in and visit. We can leverage the social networks to express our opinions about the services and places of interest (POIs). The interactions among users, and user and POIs or services generate big social media data, which have rich information for user, location, and service cognition. Many real-time network applications rely heavily on the accurate social users' locations. How to sense the locations from multisource social media data is very important and challenging. Thus, in this paper, we give a systematic review of the works that combine social media and spatial technology for POI cognition and image localization.
入藏号: WOS:000411273300009
ISSN: 0018-9219
eISSN: 1558-2256
第 41 条,共 255 条
标题: Interleaved segment correction achieves higher improvement factors in using genetic algorithm to optimize light focusing through scattering media
作者: Li, RZ (Li, Runze); Peng, T (Peng, Tong); Liang, YS (Liang, Yansheng); Yang, YL (Yang, Yanlong); Yao, BL (Yao, Baoli); Yu, XH (Yu, Xianghua); Min, JW (Min, Junwei); Lei, M (Lei, Ming); Yan, SH (Yan, Shaohui); Zhang, CM (Zhang, Chunmin); Ye, T (Ye, Tong)
来源出版物: JOURNAL OF OPTICS 卷: 19 期: 10 文献号: 105602 DOI: 10.1088/2040-8986/aa84dc 出版年: OCT 2017
摘要: Focusing and imaging through scattering media has been proved possible with high resolution wavefront shaping. A completely scrambled scattering field can be corrected by applying a correction phase mask on a phase only spatial light modulator (SLM) and thereby the focusing quality can be improved. The correction phase is often found by global searching algorithms, among which Genetic Algorithm (GA) stands out for its parallel optimization process and high performance in noisy environment. However, the convergence of GA slows down gradually with the progression of optimization, causing the improvement factor of optimization to reach a plateau eventually. In this report, we propose an interleaved segment correction (ISC) method that can significantly boost the improvement factor with the same number of iterations comparing with the conventional all segment correction method. In the ISC method, all the phase segments are divided into a number of interleaved groups; GA optimization procedures are performed individually and sequentially among each group of segments. The final correction phase mask is formed by applying correction phases of all interleaved groups together on the SLM. The ISC method has been proved significantly useful in practice because of its ability to achieve better improvement factors when noise is present in the system. We have also demonstrated that the imaging quality is improved as better correction phases are found and applied on the SLM. Additionally, the ISC method lowers the demand of dynamic ranges of detection devices. The proposed method holds potential in applications, such as high-resolution imaging in deep tissue.
入藏号: WOS:000410913300001
ISSN: 2040-8978
eISSN: 2040-8986
第 42 条,共 255 条
标题: Particle model for optical noisy image recovery via stochastic resonance
作者: Zhang, YB (Zhang, Yongbin); Liu, HJ (Liu, Hongjun); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu); Han, J (Han, Jing)
来源出版物: APPLIED PHYSICS EXPRESS 卷: 10 期: 10 文献号: 102501 DOI: 10.7567/APEX.10.102501 出版年: OCT 2017
摘要: We propose a particle model for investigating the optical noisy image recovery via stochastic resonance. The light propagating in nonlinear media is regarded as moving particles, which are used for analyzing the nonlinear coupling of signal and noise. Owing to nonlinearity, a signal seeds a potential to reinforce itself at the expense of noise. The applied electric field, noise intensity, and correlation length are important parameters that influence the recovery effects. The noise-hidden image with the signal-to-noise intensity ratio of 1 : 30 is successfully restored and an optimal cross-correlation gain of 6.1 is theoretically obtained. (C) 2017 The Japan Society of Applied Physics
入藏号: WOS:000410636600001
ISSN: 1882-0778
eISSN: 1882-0786
第 43 条,共 255 条
标题: Robust Web Image Annotation via Exploring Multi-Facet and Structural Knowledge
作者: Hu, MQ (Hu, Mengqiu); Yang, Y (Yang, Yang); Shen, FM (Shen, Fumin); Zhang, LM (Zhang, Luming); Shen, HT (Shen, Heng Tao); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 26 期: 10 页: 4871-4884 DOI: 10.1109/TIP.2017.2717185 出版年: OCT 2017
摘要: Driven by the rapid development of Internet and digital technologies, we have witnessed the explosive growth of Web images in recent years. Seeing that labels can reflect the semantic contents of the images, automatic image annotation, which can further facilitate the procedure of image semantic indexing, retrieval, and other image management tasks, has become one of the most crucial research directions in multimedia. Most of the existing annotation methods, heavily rely on well-labeled training data (expensive to collect) and/or single view of visual features (insufficient representative power). In this paper, inspired by the promising advance of feature engineering (e.g., CNN feature and scale-invariant feature transform feature) and inexhaustible image data (associated with noisy and incomplete labels) on the Web, we propose an effective and robust scheme, termed robust multi-view semi-supervised learning (RMSL), for facilitating image annotation task. Specifically, we exploit both labeled images and unlabeled images to uncover the intrinsic data structural information. Meanwhile, to comprehensively describe an individual datum, we take advantage of the correlated and complemental information derived from multiple facets of image data (i.e., multiple views or features). We devise a robust pairwise constraint on outcomes of different views to achieve annotation consistency. Furthermore, we integrate a robust classifier learning component via l(2), p loss, which can provide effective noise identification power during the learning process. Finally, we devise an efficient iterative algorithm to solve the optimization problem in RMSL. We conduct comprehensive experiments on three different data sets, and the results illustrate that our proposed approach is promising for automatic image annotation.
入藏号: WOS:000406329500022
PubMed ID: 28641261
ISSN: 1057-7149
eISSN: 1941-0042
第 44 条,共 255 条
标题: Latent semantic concept regularized model for blind image deconvolution
作者: Ye, RZ (Ye, Renzhen); Li, XL (Li, Xuelong)
来源出版物: NEUROCOMPUTING 卷: 257 页: 206-213 DOI: 10.1016/j.neucom.2016.11.064 出版年: SEP 27 2017
摘要: Blind image deconvolution refers to the recovery of a sharp image when the degradation processing is unknown. Many existing methods have the problem that they are designed to exploit low level image descriptors (e.g. image pixels or image gradient) only, rather than high-level latent semantic concepts, thus there is no guarantee of human visual perception. To address this problem, in this paper, a latent semantic concept regularized (LSCR) method is proposed to reduce the blind deconvolution problem at a semantic level. The proposed method explores the relationship between different image descriptors and exploits sparse measure to favor sharp images over blurry images. And matrix factorization is introduced to learn the latent concepts from the image descriptors. Then, the image prior can be described and constrained by the learned latent semantic concepts of image descriptors using a much more effective convolution matrix. In this case, the blind deconvolution problem can be regularized and the sharp version of the blurry image can be recovered at a new latent semantic level. Furthermore, an iterative algorithm is exploited to derive optimal solution. The proposed model is evaluated on two different datasets, including simulation dataset and real dataset, and state-of-the-art performance is achieved compared with other methods. (C) 2017 Elsevier B.V. All rights reserved.
入藏号: WOS:000404319800022
ISSN: 0925-2312
eISSN: 1872-8286
第 45 条,共 255 条
标题: System calibration method for Fourier ptychographic microscopy
作者: Pan, A (Pan, An); Zhang, Y (Zhang, Yan); Zhao, TY (Zhao, Tianyu); Wang, ZJ (Wang, Zhaojun); Dan, D (Dan, Dan); Lei, M (Lei, Ming); Yao, BL (Yao, Baoli)
来源出版物: JOURNAL OF BIOMEDICAL OPTICS 卷: 22 期: 9 文献号: 096005 DOI: 10.1117/1.JBO.22.9.096005 出版年: SEP 2017
摘要: Fourier ptychographic microscopy (FPM) is a recently proposed computational imaging technique with both high-resolution and wide field of view. In current FPM imaging platforms, systematic error sources come from aberrations, light-emitting diode (LED) intensity fluctuation, parameter imperfections, and noise, all of which may severely corrupt the reconstruction results with similar artifacts. Therefore, it would be unlikely to distinguish the dominating error from these degraded reconstructions without any preknowledge. In addition, systematic error is generally a mixture of various error sources in the real situation, and it cannot be separated due to their mutual restriction and conversion. To this end, we report a system calibration procedure, termed SC-FPM, to calibrate the mixed systematic errors simultaneously from an overall perspective, based on the simulated annealing algorithm, the LED intensity correction method, the nonlinear regression process, and the adaptive step-size strategy, which involves the evaluation of an error metric at each iteration step, followed by the re-estimation of accurate parameters. The performance achieved both in simulations and experiments demonstrates that the proposed method outperforms other state-of-the-art algorithms. The reported system calibration scheme improves the robustness of FPM, relaxes the experiment conditions, and does not require any preknowledge, which makes the FPM more pragmatic. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000413570000029
ISSN: 1083-3668
eISSN: 1560-2281
第 46 条,共 255 条
标题: An improved non-uniformity correction algorithm and its hardware implementation on FPGA
作者: Rong, SH (Rong Shenghui); Zhou, HX (Zhou Huixin); Wen, ZG (Wen Zhigang); Qin, HL (Qin Hanlin); Qian, K (Qian Kun); Cheng, KH (Cheng Kuanhong)
来源出版物: INFRARED PHYSICS & TECHNOLOGY 卷: 85 页: 410-420 DOI: 10.1016/j.infrared.2017.07.007 出版年: SEP 2017
摘要: The Non-uniformity of Infrared Focal Plane Arrays (IRFPA) severely degrades the infrared image quality. An effective non-uniformity correction (NUC) algorithm is necessary for an IRFPA imaging and application system. However traditional scene-based NUC algorithm suffers the image blurring and artificial ghosting. In addition, few effective hardware platforms have been proposed to implement corresponding NUC algorithms. Thus, this paper proposed an improved neural-network based NUC algorithm by the guided image filter and the projection-based motion detection algorithm. First, the guided image filter is utilized to achieve the accurate desired image to decrease the artificial ghosting. Then a projection based moving detection algorithm is utilized to determine whether the correction coefficients should be updated or not. In this way the problem of image blurring can be overcome. At last, an FPGA-based hardware design is introduced to realize the proposed NUC algorithm. A real and a simulated infrared image sequences are utilized to verify the performance of the proposed algorithm. Experimental results indicated that the proposed NUC algorithm can effectively eliminate the fix pattern noise with less image blurring and artificial ghosting. The proposed hardware design takes less logic elements in FPGA and spends less clock cycles to process one frame of image. (C) 2017 Published by Elsevier B.V.
入藏号: WOS:000411546800052
ISSN: 1350-4495
eISSN: 1879-0275
第 47 条,共 255 条
标题: Transmission performance of 90 degrees-bend optical waveguides fabricated in fused silica by femtosecond laser inscription
作者: Lv, J (Lv, Jing); Bai, J (Bai, Jing); Zhou, KM (Zhou, Kaiming); Mei, XS (Mei, Xuesong); Wang, KD (Wang, Kedian); Li, M (Li, Ming); Cheng, GH (Cheng, Guanghua)
来源出版物: OPTICS LETTERS 卷: 42 期: 17 页: 3470-3473 DOI: 10.1364/OL.42.003470 出版年: SEP 1 2017
摘要: The L-shape waveguide was written in fused silica using a femtosecond laser with beam shaping. The guiding structure supports good light turning; 0.88 dB/turn was achieved at the silica-air interface. By using the finite-different time-domain method, the turn loss due to the turning structure and refractive index of the L-shape waveguide has been simulated. The results show that the proposed method has unprecedented flexibility in fabricating a 90 degrees-bend waveguide. (c) 2017 Optical Society of America
入藏号: WOS:000408952100057
PubMed ID: 28957065
ISSN: 0146-9592
eISSN: 1539-4794
第 48 条,共 255 条
标题: Natural healing behavior of gamma radiation induced defects in multicomponent phosphate glasses used for high energy UV lasers
作者: He, QL (He, Quanlong); Xue, YK (Xue, Yaoke); Wang, PF (Wang, Pengfei); Sun, MY (Sun, Mengya); Lu, M (Lu, Min); Peng, B (Peng, Bo)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 7 期: 9 页: 3284-3293 DOI: 10.1364/OME.7.003284 出版年: SEP 1 2017
摘要: Obvious healing behavior of gamma radiation induced defects in multicomponent phosphate glass was observed at room temperature. The recovery of the defects depends on the ratio of H3BO3/SiO2 in the investigated glasses, the total gamma radiation dose, and the time of ageing at room temperature. Meanwhile, the synchronous decreases of PO3-EC and POHC defects contribute to the corresponding recovery of the transmittance change at 385 nm and 525 nm, which could be described by the charge transfer. Besides, a general model of the healing mechanism associated with the release and capture of the electrons between PO3-EC and POHC defects in these phosphate glass was proposed. (C) 2017 Optical Society of America
入藏号: WOS:000408952600022
ISSN: 2159-3930
第 49 条,共 255 条
标题: Remote Sensing Scene Classification by Unsupervised Representation Learning
作者: Lu, XQ (Lu, Xiaoqiang); Zheng, XT (Zheng, Xiangtao); Yuan, Y (Yuan, Yuan)
来源出版物: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 卷: 55 期: 9 页: 5148-5157 DOI: 10.1109/TGRS.2017.2702596 出版年: SEP 2017
摘要: With the rapid development of the satellite sensor technology, high spatial resolution remote sensing (HSR) data have attracted extensive attention in military and civilian applications. In order to make full use of these data, remote sensing scene classification becomes an important and necessary precedent task. In this paper, an unsupervised representation learning method is proposed to investigate deconvolution networks for remote sensing scene classification. First, a shallow weighted deconvolution network is utilized to learn a set of feature maps and filters for each image by minimizing the reconstruction error between the input image and the convolution result. The learned feature maps can capture the abundant edge and texture information of high spatial resolution images, which is definitely important for remote sensing images. After that, the spatial pyramid model (SPM) is used to aggregate features at different scales to maintain the spatial layout of HSR image scene. A discriminative representation for HSR image is obtained by combining the proposed weighted deconvolution model and SPM. Finally, the representation vector is input into a support vector machine to finish classification. We apply our method on two challenging HSR image data sets: the UCMerced data set with 21 scene categories and the Sydney data set with seven land-use categories. All the experimental results achieved by the proposed method outperform most state of the arts, which demonstrates the effectiveness of the proposed method.
入藏号: WOS:000408346600024
作者识别号:
作者        ResearcherID 号        ORCID 号
Lu, Xiaoqiang                  0000-0002-7037-5188
ISSN: 0196-2892
eISSN: 1558-0644
第 50 条,共 255 条
标题: Dimensionality Reduction by Spatial-Spectral Preservation in Selected Bands
作者: Zheng, XT (Zheng, Xiangtao); Yuan, Y (Yuan, Yuan); Lu, XQ (Lu, Xiaoqiang)
来源出版物: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 卷: 55 期: 9 页: 5185-5197 DOI: 10.1109/TGRS.2017.2703598 出版年: SEP 2017
摘要: Dimensionality reduction (DR) has attracted extensive attention since it provides discriminative information of hyperspectral images (HSI) and reduces the computational burden. Though DR has gained rapid development in recent years, it is difficult to achieve higher classification accuracy while preserving the relevant original information of the spectral bands. To relieve this limitation, in this paper, a different DR framework is proposed to perform feature extraction on the selected bands. The proposed method uses determinantal point process to select the representative bands and to preserve the relevant original information of the spectral bands. The performance of classification is further improved by performing multiple Laplacian eigenmaps (LEs) on the selected bands. Different from the traditional LEs, multiple Laplacian matrices in this paper are defined by encoding spatial-spectral proximity on each band. A common low-dimensional representation is generated to capture the joint manifold structure from multiple Laplacian matrices. Experimental results on three real-world HSIs demonstrate that the proposed framework can lead to a significant advancement in HSI classification compared with the state-of-the-art methods.
入藏号: WOS:000408346600027
作者识别号:
作者        ResearcherID 号        ORCID 号
Lu, Xiaoqiang                  0000-0002-7037-5188
ISSN: 0196-2892
eISSN: 1558-0644

第 51 条,共 255 条
标题: Fast polarimetric dehazing method for visibility enhancement in HSI colour space
作者: Zhang, WF (Zhang, Wenfei); Liang, J (Liang, Jian); Ren, LY (Ren, Liyong); Ju, HJ (Ju, Haijuan); Bai, ZF (Bai, Zhaofeng); Wu, ZX (Wu, Zhaoxin)
来源出版物: JOURNAL OF OPTICS 卷: 19 期: 9 文献号: 095606 DOI: 10.1088/2040-8986/aa7f39 出版年: SEP 2017
摘要: Image haze removal has attracted much attention in optics and computer vision fields in recent years due to its wide applications. In particular, the fast and real-time dehazing methods are of significance. In this paper, we propose a fast dehazing method in hue, saturation and intensity colour space based on the polarimetric imaging technique. We implement the polarimetric dehazing method in the intensity channel, and the colour distortion of the image is corrected using the white patch retinex method. This method not only reserves the detailed information restoration capacity, but also improves the efficiency of the polarimetric dehazing method. Comparison studies with state of the art methods demonstrate that the proposed method obtains equal or better quality results and moreover the implementation is much faster. The proposed method is promising in real-time image haze removal and video haze removal applications.
入藏号: WOS:000408250500001
ISSN: 2040-8978
eISSN: 2040-8986
第 52 条,共 255 条
标题: Discrete Nonnegative Spectral Clustering
作者: Yang, Y (Yang, Yang); Shen, FM (Shen, Fumin); Huang, Z (Huang, Zi); Shen, HT (Shen, Heng Tao); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 卷: 29 期: 9 页: 1834-1845 DOI: 10.1109/TKDE.2017.2701825 出版年: SEP 1 2017
摘要: Spectral clustering has been playing a vital role in various research areas. Most traditional spectral clustering algorithms comprise two independent stages (e.g., first learning continuous labels and then rounding the learned labels into discrete ones), which may cause unpredictable deviation of resultant cluster labels from genuine ones, thereby leading to severe information loss and performance degradation. In this work, we study how to achieve discrete clustering as well as reliably generalize to unseen data. We propose a novel spectral clustering scheme which deeply explores cluster label properties, including discreteness, nonnegativity, and discrimination, as well as learns robust out-of-sample prediction functions. Specifically, we explicitly enforce a discrete transformation on the intermediate continuous labels, which leads to a tractable optimization problem with a discrete solution. Besides, we preserve the natural nonnegative characteristic of the clustering labels to enhance the interpretability of the results. Moreover, to further compensate the unreliability of the learned clustering labels, we integrate an adaptive robust module with l(2,p) loss to learn prediction function for grouping unseen data. We also show that the out-of-sample component can inject discriminative knowledge into the learning of cluster labels under certain conditions. Extensive experiments conducted on various data sets have demonstrated the superiority of our proposal as compared to several existing clustering approaches.
入藏号: WOS:000407433900005
ISSN: 1041-4347
eISSN: 1558-2191
第 53 条,共 255 条
标题: Learning Bregman Distance Functions for Structural Learning to Rank
作者: Li, X (Li, Xi); Pi, T (Pi, Te); Zhang, ZF (Zhang, Zhongfei); Zhao, XY (Zhao, Xueyi); Wang, M (Wang, Meng); Li, XL (Li, Xuelong); Yu, PS (Yu, Philip S.)
来源出版物: IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 卷: 29 期: 9 页: 1916-1927 DOI: 10.1109/TKDE.2017.2654250 出版年: SEP 1 2017
摘要: We study content-based learning to rank from the perspective of learning distance functions. Standardly, the two key issues of learning to rank, feature mappings and score functions, are usually modeled separately, and the learning is usually restricted to modeling a linear distance function such as the Mahalanobis distance. However, the modeling of feature mappings and score functions are mutually interacted, and the patterns underlying the data are probably complicated and nonlinear. Thus, as a general nonlinear distance family, the Bregman distance is a suitable distance function for learning to rank, due to its strong generalization ability for distance functions, and its nonlinearity for exploring the general patterns of data distributions. In this paper, we study learning to rank as a structural learning problem, and devise a Bregman distance function to build the ranking model based on structural SVM. To improve the model robustness to outliers, we develop a robust structural learning framework for the ranking model. The proposed model Robust Structural Bregman distance functions Learning to Rank (RSBLR) is a general and unified framework for learning distance functions to rank. The experiments of data ranking on real-world datasets show the superiority of this method to the state-of-the-art literature, as well as its robustness to the noisily labeled outliers.
入藏号: WOS:000407433900011
ISSN: 1041-4347
eISSN: 1558-2191
第 54 条,共 255 条
标题: Modeling Information Diffusion over Social Networks for Temporal Dynamic Prediction
作者: Li, D (Li, Dong); Zhang, SP (Zhang, Shengping); Sun, X (Sun, Xin); Zhou, HY (Zhou, Huiyu); Li, S (Li, Sheng); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 卷: 29 期: 9 页: 1985-1997 DOI: 10.1109/TKDE.2017.2702162 出版年: SEP 1 2017
摘要: Modeling the process of information diffusion is a challenging problem. Although numerous attempts have been made in order to solve this problem, very few studies are actually able to simulate and predict temporal dynamics of the diffusion process. In this paper, we propose a novel information diffusion model, namely GT model, which treats the nodes of a network as intelligent and rational agents and then calculates their corresponding payoffs, given different choices to make strategic decisions. By introducing time-related payoffs based on the diffusion data, the proposed GT model can be used to predict whether or not the user's behaviors will occur in a specific time interval. The user's payoff can be divided into two parts: social payoff from the user's social contacts and preference payoff from the user's idiosyncratic preference. We here exploit the global influence of the user and the social influence between any two users to accurately calculate the social payoff. In addition, we develop a new method of presenting social influence that can fully capture the temporal dynamics of social influence. Experimental results from two different datasets, Sina Weibo and Flickr demonstrate the rationality and effectiveness of the proposed prediction method with different evaluation metrics.
入藏号: WOS:000407433900016
ISSN: 1041-4347
eISSN: 1558-2191
第 55 条,共 255 条
标题: Intrinsic reduction the depolarization loss in electro-optical Q-switched laser using a rectangular KD*P crystal
作者: Yin, XL (Yin, Xingliang); Jiang, MH (Jiang, Menghua); Sun, Z (Sun, Zhe); Hui, YL (Hui, Yongling); Lei, H (Lei, Hong); Li, Q (Li, Qiang)
来源出版物: OPTICS COMMUNICATIONS 卷: 398 页: 107-111 DOI: 10.1016/j.optcom.2017.04.048 出版年: SEP 1 2017
摘要: We presented the first demonstration of a new structure KD*P crystal as electro-optic switch, in which the thermal depolarization loss was intrinsically reduced. The thermally induced birefringence and depolarization of both cylindrical and rectangular crystalline structure were simulated. The higher pulse energy or average power output was achieved in the diode pumped E-O Q-switched laser using a rectangular KD*P crystal. At the repetition rate of 100 Hz, the maximum average output power was 27.2 W at 145 A pump current, corresponding to the pulse energy was 272 mJ with pulse width of 65 ns and the beam quality of M-2=20.4. Comparing the highest average power or corresponding single pulse energy, the laser with the rectangular KD*P crystal was two times of the laser with the traditional cylindrical KD*P crystal.
入藏号: WOS:000401391200017
ISSN: 0030-4018
eISSN: 1873-0310
第 56 条,共 255 条
标题: Formation, element-migration and broadband luminescence in quantum dot-doped glass fibers
作者: Huang, XJ (Huang, Xiongjian); Fang, ZJ (Fang, Zaijin); Peng, ZX (Peng, Zixing); Ma, ZJ (Ma, Zhijun); Guo, HT (Guo, Haitao); Qiu, JR (Qiu, Jianrong); Dong, GP (Dong, Guoping)
来源出版物: OPTICS EXPRESS 卷: 25 期: 17 页: 19691-19700 DOI: 10.1364/OE.25.019691 出版年: AUG 21 2017
摘要: All solid-state PbS quantum dot (QD)-doped glass precursor fibers avoiding crystallization during fiber-drawing process are successfully fabricated by melt-in-tube technique. By subsequent heat treatment schedule, controllable crystallization of PbS QDs can be obtained in the glass precursor fibers, contributing to broad near-infrared emissions from PbS QD-doped glass fibers. Nevertheless, we find that element-migration and volatilization of sulfur simultaneously happen during the whole fiber-drawing process, because of the huge difference between the melting temperature of core glass and the fiber-drawing temperature. Element-migration pathways along the fiber length were revealed. Such PbS QD-doped glass fiber with broadband emissions will be a potential application as gain medium of broadband fiber amplifiers and fiber lasers. (C) 2017 Optical Society of America
入藏号: WOS:000409338000005
PubMed ID: 29041657
ISSN: 1094-4087
第 57 条,共 255 条
标题: High Verdet constants and diamagnetic responses of GeS2-In2S3-PbI2 chalcogenide glasses for integrated optics applications
作者: Xu, YT (Xu, Yantao); Guo, HT (Guo, Haitao); Xiao, XS (Xiao, Xusheng); Wang, PF (Wang, Pengfei); Cui, XX (Cui, Xiaoxia); Lu, M (Lu, Min); Lin, CG (Lin, Changgui); Dai, SX (Dai, Shixun); Peng, B (Peng, Bo)
来源出版物: OPTICS EXPRESS 卷: 25 期: 17 页: 20410-20420 DOI: 10.1364/OE.25.020410 出版年: AUG 21 2017
摘要: Chalcogenide glasses as kind of diamagnetic magneto-optical materials have promising applications in the field of integrated optics and optical communication systems due to their excellent properties, such as easy to be processed into waveguide and temperature independence of the Verdet constants. For clarifying the influence factors following the compositional variation on Faraday effect and finding a glass with a large Verdet constant, novel pseudo-ternary chalcogenide glass system, GeS2 - In2S3 - PbI2, was prepared and investigated. The composition, wavelength and temperature dependences on the Verdet constants were systematically investigated at the wavelengths of 635, 808, 980 and 1319 nm. PbI2 was confirmed to have positive contribution to the Verdet constant and the Becquerel rule was proved to be an effective guidance for predicting the Verdet constant in chalcogenide glasses. The 60GeS(2)center dot 15In(2)S(3)center dot 25PbI(2) glass was found to possess the largest Verdet constant (V = 0.215 min.G(-1).cm(-1), @808nm), which is great larger than that of commercial diamagnetic glasses. These glasses also possess good glass-forming ability and VIS-IR transmittance, therefore be a good candidate for next-generation integrated optical isolator and other magneto-optical devices. (C) 2017 Optical Society of America
入藏号: WOS:000409338000070
PubMed ID: 29041722
作者识别号:
作者        ResearcherID 号        ORCID 号
Lin, Changgui         B-8915-2009         0000-0002-0574-6296
ISSN: 1094-4087
第 58 条,共 255 条
标题: High Temporal and Spatial Resolution Distributed Fiber Bragg Grating Sensors Using Time-Stretch Frequency-Domain Reflectometry
作者: Ahmad, EJ (Ahmad, Eamonn J.); Wang, C (Wang, Chao); Feng, DJ (Feng, Dejun); Yan, ZJ (Yan, Zhijun); Zhang, L (Zhang, Lin)
来源出版物: JOURNAL OF LIGHTWAVE TECHNOLOGY 卷: 35 期: 16 页: 3289-3295 DOI: 10.1109/JLT.2016.2605401 出版年: AUG 15 2017
摘要: A novel interrogation technique for fully distributed linearly chirped fiber Bragg grating (LCFBG) strain sensors with simultaneous high temporal and spatial resolution based on optical time-stretch frequency-domain reflectometry (OTS-FDR) is proposed and experimentally demonstrated. LCFBGs is a promising candidate for fully distributed sensors thanks to its longer grating length and broader reflection bandwidth compared to normal uniform FBGs. In the proposed system, two identical LCFBGs are employed in a Michelson interferometer setup with one grating serving as the reference grating whereas the other serving as the sensing element. Broadband spectral interferogram is formed and the strain information is encoded into the wavelength-dependent free spectral range (FSR). Ultrafast interrogation is achieved based on dispersion-induced time stretch such that the target spectral interferogram is mapped to a temporal interference waveform that can be captured in real-time using a single-pixel photodetector. The distributed strain along the sensing grating can be reconstructed from the instantaneous RF frequency of the captured waveform. High-spatial resolution is also obtained due to high-speed data acquisition. In a proof-of-concept experiment, ultrafast real-time interrogation of fully distributed grating sensors with various strain distributions is experimentally demonstrated. An ultrarapid measurement speed of 50 MHz with a high spatial resolution of 31.5 mu m over a gauge length of 25 mm and a strain resolution of 9.1 mu epsilon have been achieved.
入藏号: WOS:000405372900005
作者识别号:
作者        ResearcherID 号        ORCID 号
Wang, Chao         F-9805-2010         0000-0002-0454-8079
ISSN: 0733-8724
eISSN: 1558-2213
第 59 条,共 255 条
标题: A novel strategy to prepare 2D YBO3: Ce3+-Yb3+ nanosheets with enhanced near-infrared (NIR) emission properties
作者: Miao, H (Miao, Hui); Zhang, GW (Zhang, Guowei); Hu, XY (Hu, Xiaoyun); Liu, EZ (Liu, Enzhou); Bai, JT (Bai, Jintao); Hou, X (Hou, Xun)
来源出版物: JOURNAL OF CONTROLLED RELEASE 卷: 259 页: E49-E49 DOI: 10.1016/j.jconrel.2017.03.121 出版年: AUG 10 2017
入藏号: WOS:000407591400080
会议名称: 4th Symposium on Innovative Polymers for Controlled Delivery (SIPCD)
会议日期: SEP 23-26, 2016
会议地点: Suzhou, PEOPLES R CHINA
ISSN: 0168-3659
eISSN: 1873-4995
第 60 条,共 255 条
标题: Noninvasive blood glucose detection using a miniature wearable Raman spectroscopy system
作者: Zheng, Y (Zheng, Yi); Zhu, XP (Zhu, Xiangping); Wang, Z (Wang, Zhe); Hou, ZY (Hou, Zongyu); Gao, F (Gao, Fei); Nie, RZ (Nie, Rongzhi); Cui, XX (Cui, Xiaoxia); She, JB (She, Jiangbo); Peng, B (Peng, Bo)
来源出版物: CHINESE OPTICS LETTERS 卷: 15 期: 8 文献号: 083001 DOI: 10.3788/COL201715.083001 出版年: AUG 10 2017
摘要: In this Letter, a miniature wearable Raman spectroscopy system is developed. A wearable fiber-optic probe is employed to help the stable and convenient collection of Raman spectra. A nonlinear partial least squares model based on a multivariate dominant factor is employed to predict the glucose level. The mean coefficients of determination are 0.99, 0.893, and 0.844 for the glucose solution, laboratory rats, and human volunteers. The results demonstrate that a miniature wearable Raman spectroscopy system is feasible to achieve the noninvasive detection of human blood glucose and has important clinical application value in disease diagnosis.
入藏号: WOS:000407438600024
作者识别号:
作者        ResearcherID 号        ORCID 号
Wang, Zhe         E-1705-2011         0000-0001-6857-7672
ISSN: 1671-7694
第 61 条,共 255 条
标题: Optical fluxes in coupled PT-symmetric photonic structures
作者: Ge, L (Ge, Li); Makris, KG (Makris, Konstantinos G.); Zhang, LX (Zhang, Lingxuan)
来源出版物: PHYSICAL REVIEW A 卷: 96 期: 2 文献号: 023820 DOI: 10.1103/PhysRevA.96.023820 出版年: AUG 9 2017
摘要: In this work we first examine transverse and longitudinal fluxes in a PT-symmetric photonic dimer using a coupled-mode theory. Several surprising understandings are obtained from this perspective: The longitudinal flux shows that the PT transition in a dimer can be regarded as a classical effect, despite its analogy to PT-symmetric quantum mechanics. The longitudinal flux also indicates that the so-called giant amplification in the PT-symmetric phase is a subexponential behavior and does not outperform a single gain waveguide. The transverse flux, on the other hand, reveals that the apparent power oscillations between the gain and loss waveguides in the PT-symmetric phase can be deceiving in certain cases, where the transverse power transfer is in fact unidirectional. We also show that this power transfer cannot be arbitrarily fast even when the exceptional point is approached. Finally, we go beyond the coupled-mode theory by using the paraxial wave equation and also extend our discussions to a PT diamond and a one-dimensional periodic lattice.
入藏号: WOS:000407262400012
ISSN: 2469-9926
eISSN: 2469-9934
第 62 条,共 255 条
标题: Practical system for the generation of pulsed quantum frequency combs
作者: Roztocki, P (Roztocki, Piotr); Kues, M (Kues, Michael); Reimer, C (Reimer, Christian); Wetzel, B (Wetzel, Benjamin); Sciara, S (Sciara, Stefania); Zhang, YB (Zhang, Yanbing); Cino, A (Cino, Alfonso); Little, BE (Little, Brent E.); Chu, ST (Chu, Sai T.); Moss, DJ (Moss, David J.); Morandotti, R (Morandotti, Roberto)
来源出版物: OPTICS EXPRESS 卷: 25 期: 16 页: 18940-18949 DOI: 10.1364/OE.25.018940 出版年: AUG 7 2017
摘要: The on-chip generation of large and complex optical quantum states will enable low-cost and accessible advances for quantum technologies, such as secure communications and quantum computation. Integrated frequency combs are on-chip light sources with a broad spectrum of evenly-spaced frequency modes, commonly generated by four-wave mixing in optically-excited nonlinear micro-cavities, whose recent use for quantum state generation has provided a solution for scalable and multi-mode quantum light sources. Pulsed quantum frequency combs are of particular interest, since they allow the generation of single-frequency-mode photons, required for scaling state complexity towards, e.g., multi-photon states, and for quantum information applications. However, generation schemes for such pulsed combs have, to date, relied on micro-cavity excitation via lasers external to the sources, being neither versatile nor power-efficient, and impractical for scalable realizations of quantum technologies. Here, we introduce an actively-modulated, nested-cavity configuration that exploits the resonance pass-band characteristic of the micro-cavity to enable a mode-locked and energy-efficient excitation. We demonstrate that the scheme allows the generation of high-purity photons at large coincidence-to-accidental ratios (CAR). Furthermore, by increasing the repetition rate of the excitation field via harmonic mode-locking (i.e. driving the cavity modulation at harmonics of the fundamental repetition rate), we managed to increase the pair production rates (i.e. source efficiency), while maintaining a high CAR and photon purity. Our approach represents a significant step towards the realization of fully on-chip, stable, and versatile sources of pulsed quantum frequency combs, crucial for the development of accessible quantum technologies. (C) 2017 Optical Society of America
入藏号: WOS:000409326900053
PubMed ID: 29041085
作者识别号:
作者        ResearcherID 号        ORCID 号
moss, david                  0000-0001-5195-1744
CHU, Sai Tak                  0000-0001-8263-8507
ISSN: 1094-4087
第 63 条,共 255 条
标题: Recent progress of high-coherence ultrafast electron sources
作者: Luo, D (Luo Duan); Hui, DD (Hui Dan-Dan); Wen, WL (Wen Wen-Long); Liu, R (Liu Rong); Wang, X (Wang Xing); Tian, JS (Tian Jin-Shou)
来源出版物: ACTA PHYSICA SINICA 卷: 66 期: 15 文献号: 152901 DOI: 10.7498/aps.66.152901 出版年: AUG 5 2017
摘要: Microscopic dynamic process of material structure which determines the inherent property of substance takes place on a molecular and atomic scale. Understanding the underlying mechanisms of the various fundamental processes has always been the goal of chemistry, physics, biology and materials science. With Ahmed Zewail's pioneering work in the field of femtoscience, the time-resolved electron diffraction, combining the pump-probe and electron diffraction technique, has become an excellent tool with sufficient temporal precision to directly deliver insights into ultrafast phenomena on an atomic level. Central to this method is the ultrashort electron pulses generated from a metal photocathode.
However, up to now, owing to the initial size, effective temperature, energy dispersion and inherent coulomb repulsion of electron source, the state-of-the-art transverse coherence of conventional planar cathode photoemission source is still insufficient to resolve the complex chemical and biological organic molecules. Hence, in recent years, many efforts have focused on developing high-coherence ultrashort electron sources. The main methods include minimizing the initial beam size, weakening the space charge, reducing the effective temperature, and matching the photon energy of laser with the work function of cathode material.
In this review, we firstly summarize the history and advantages of the electron probe, secondly sketch out the figure of merit of the electron source. And then taking coherence as the main line, we review recent progress in common planar photoemission sources, and discuss the latest development of tip-based electron sources and cold atom electron sources in terms of their generation mechanisms, unique properties and research progress. Finally, the development and future applications of the diffraction technique are prospected. In general, the high-coherence length of photoelectric surface source is often at the expense of the current. The needle source can obtain the highest coherence length, but it is similar to femtosecond single-electron pulse, which must be less than one electron per pulse to eliminate the electron-electron coulomb interaction. Thus, a diffraction pattern can only be formed by accumulating millions of shots. The cold atom electron source, which has a transverse coherence greater than 15 nm and a peak brightness similar to conventional electron source's, is sufficient for some molecular systems in biochemistry. In short, with the improvement of coherence and the emergence of new electron sources, it is possible to reveal complex organic and inorganic structures, especially the dynamic behaviors of protein, and promote the understanding of nanoscale energy transport, solid-liquid and solid-gas interfacial dynamics and chemical reaction and so on. High-coherence electron sources not only serve in the diffraction experiments, but also play a key role in developing ultrafast electron microscopy, coherent diffraction imaging and ptychography.
入藏号: WOS:000410775700007
ISSN: 1000-3290
第 64 条,共 255 条
标题: Overlapping Community Detection for Multimedia Social Networks
作者: Huang, FL (Huang, Faliang); Li, XL (Li, Xuelong); Zhang, SC (Zhang, Shichao); Zhang, JL (Zhang, Jilian); Chen, JH (Chen, Jinhui); Zhai, ZN (Zhai, Zhinian)
来源出版物: IEEE TRANSACTIONS ON MULTIMEDIA 卷: 19 期: 8 页: 1881-1893 DOI: 10.1109/TMM.2017.2692650 出版年: AUG 2017
摘要: Finding overlapping communities from multimedia social networks is an interesting and important problem in data mining and recommender systems. However, extant overlapping community discovery with swarm intelligence often generates overlapping community structures with superfluous small communities. To deal with the problem, in this paper, an efficient algorithm (LEPSO) is proposed for overlapping communities discovery, which is based on line graph theory, ensemble learning, and particle swarm optimization (PSO). Specifically, a discrete PSO, consisting of an encoding scheme with ordered neighbors and a particle updating strategy with ensemble clustering, is devised for improving the optimization ability to search communities hidden in social networks. Then, a postprocessing strategy is presented for merging the finer-grained and suboptimal overlapping communities. Experiments on some real-world and synthetic datasets show that our approach is superior in terms of robustness, effectiveness, and automatically determination of the number of clusters, which can discover overlapping communities that have better quality than those computed by state-of-the-art algorithms for overlapping communities detection.
入藏号: WOS:000411240400016
ISSN: 1520-9210
eISSN: 1941-0077
第 65 条,共 255 条
标题: Effects of doping B2O3 on the defects-state in SiO2-containing phosphate based glasses
作者: He, QL (He, Quanlong); Wang, PF (Wang, Pengfei); Sun, MY (Sun, Mengya); Lu, M (Lu, Min); Peng, B (Peng, Bo)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 7 期: 8 页: 2697-2705 DOI: 10.1364/OME.7.002697 出版年: AUG 1 2017
摘要: The effects of doping B2O3 on the defects and their induced anti-radiation performance change of the multicomponent phosphate glasses were studied in this Work. The introduction of B2O3 reduces the connectivity of phosphate chains and thus increases the concentration of PO3-EC and PO4-EC defects in the phosphate glass network that have large absorption in the high-energy region. Meanwhile, B2O3 can improve the oxidizability of those glasses at the same melting temperature under which Fe ions Will be more easily oxidized to Fe ions. However the addition of B2O3 in terms of H3BO3 as it reaches up to 7.5 wt%, could enhance the gamma radiation resistance of the phosphate glasses, in this case B(2)O(3)3, and enter the phosphate glass network in the form of B5O8 units. The units enhanced the connectivity of the long phosphate chains and thus reduced the concentration of PO3-EC and PO4-EC defects in phosphate glasses. (C) 2017 Optical Society of America
入藏号: WOS:000407384100001
ISSN: 2159-3930
第 66 条,共 255 条
标题: Passively Q-switched Nd:YVO4 laser based on Fe3O4 nanoparticles saturable absorber
作者: Wang, X (Wang, Xi); Wang, YG (Wang, Yonggang); Mao, D (Mao, Dong); Li, L (Li, Lu); Chen, ZD (Chen, Zhendong)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 7 期: 8 页: 2913-2921 DOI: 10.1364/OME.7.002913 出版年: AUG 1 2017
摘要: We report on a passively Q-switched Nd:YVO4 laser at 1064.34 nm by using the ferroferric-oxide (Fe3O4) nanoparticles (FONPs) saturable absorber (SA). It is corroborated that the FONPs SA exhibits a large nonlinear saturable absorption property with the modulation depth of 2.49% at the laser wavelength of 1 mu m. By inserting the novel SA into a V-type Nd: YVO4 laser cavity, we obtain the shortest pulse duration of 53 ns with a repetition rate of 576.4 kHz. The corresponding average output power, single pulse energy, and peak power are 104 mW, 0.18 mu J, and 3.53 W, respectively. To the best of our knowledge, it is the first time to experimentally confirm the application of FONPs in a pulsed Nd: YVO4 solid state laser. The parameters of the pulse width, average output power, and peak power are superior to those in the reported pulsed fiber lasers with FONPs SA so far. (C) 2017 Optical Society of America
入藏号: WOS:000407384100022
ISSN: 2159-3930
第 67 条,共 255 条
标题: Study on the Polarization Spectral Image Dehazing
作者: Xia, P (Xia Pu); Liu, XB (Liu Xue-bin)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 37 期: 8 页: 2331-2338 DOI: 10.3964/j.issn.1000-0593(2017)08-2331-08 出版年: AUG 2017
摘要: Air pollution has a serious effect on the quality of image, and image taking under hazy weather suffers from poor contrast and resolution. It is of great significance to use the polarimetric spectral information for image dehazing and the research of polarization dehazing for spectral data cube. The data used in this paper was pushbroomed under moderate hazy weather, and original Vis-NIR polarimetric data of 380 similar to 1 000 nm was captured, the original polarimetric images at 450, 550, 650, 750, 850 nm and the dehazed images were studied. The results of the research showed that wavelength had a significant effect on the difference of gray value between targets and background, and both the dynamic range of gray value and the smoothness of histogram were improved after the dehazing process. On average, the image contrast of the far-field targets increased by 5 times. The far-field targets at 450 nm had the lowest contrast, and the dehazing process increased the image contrast by 7.13 times which made the undetectable targets detectable. The far-field targets at 850 nm had the highest contrast, and the dehazing process increased the image contrast by 3.86 times. The dynamic range of histogram of the full image increased to 13.5% to 28.6% from 450 to 850 nm, the dynamic range of histogram of the near-field targets are increased to 33.3% to 44.0%. Based on the analyzation of the possible estimation error, two correction factors were proposed to revise the degree of polarization of the airlight and the intensity of the airlight from an object at an infinite distance, the regularity of the two factors were given to guide the image dehazing process under new conditions. The polarimetric information is obtained through the original data by the Stokes parameters, the dehazing process is based on the polarimetric difference between the air light scattered from the haze particles and the direct light reflected from the objects. The polarization spectral dehazing technique not only expands the application area of the imaging spectrometer, but also provides a new idea for image dehazing.
入藏号: WOS:000408520400002
ISSN: 1000-0593
第 68 条,共 255 条
标题: Design of Hyperspectral Polarimetic Imaging System Based on LCTF and LCVR
作者: Yang, FC (Yang Fan-chao); Li, Y (Li Yong); Hu, BL (Hu Bing-liang); Kong, L (Kong Liang); Wei, RY (Wei Ru-yi); Li, HB (Li Hong-bo)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 37 期: 8 页: 2610-2614 DOI: 10.3964/j.issn.1000-0593(2017)08-2610-05 出版年: AUG 2017
摘要: A hyperspectral polarimetic imaging system was proposed based on LCTF and LCVR. The system could break the limit of incomplete polarization acquiring by the conventional single LCTF system and acquire the full Stokes parameters of targets. It used the 4 different groups of phase retardance of LCVRs to build a 4X4 inversion algorithm matrix to calculate the original full polarization information. After calibration of the Retardance-Voltage characters of two LCVRs, the inversion algorithm was verified by laser at 633nm. The measured errors of full Stokes parameters, corresponding calculated degree and angel of linear polarization were analyzed, and the inversion algorithm was proved work well. The results indicated that the hyperspectral polarimetric imaging system could provide reliable hyperspectral and polarization information for remote sensing.
入藏号: WOS:000408520400050
ISSN: 1000-0593
第 69 条,共 255 条
标题: Design of a smooth freeform illumination system for a point light source based on polar-type optimal transport mapping
作者: Mao, XL (Mao, Xianglong); Xu, SB (Xu, Songbo); Hu, XR (Hu, Xinrong); Xie, YJ (Xie, Yongjun)
来源出版物: APPLIED OPTICS 卷: 56 期: 22 页: 6324-6331 DOI: 10.1364/AO.56.006324 出版年: AUG 1 2017
摘要: A design method is proposed to generate smooth freeform illumination optics for a point light source based on the L-2 optimal transport (LOT) mapping. In this method, the LOT mapping between an assumed circular planar source and a prescribed target is first obtained by solving a polar-type LOT problem. Then, the mapping calculated for the circular source is applied for a point light source. Finally, the freeform optical surface is generated by a geometric construction method to realize the ray mapping. As examples, a series of smooth-surface freeform lenses are designed for a point light source to form uniform and complex illumination patterns on rectangular targets. The ray-tracing results show that all the designs achieve excellent performance with the light utilization efficiency eta over 0.87 (Fresnel loss considered) and the relative standard deviation (RSD) of the simulated illumination distribution less than 0.051 simultaneously. (C) 2017 Optical Society of America
入藏号: WOS:000406939100038
PubMed ID: 29047831
ISSN: 1559-128X
eISSN: 2155-3165
第 70 条,共 255 条
标题: Reweighted Infrared Patch-Tensor Model With Both Nonlocal and Local Priors for Single-Frame Small Target Detection
作者: Dai, YM (Dai, Yimian); Wu, YQ (Wu, Yiquan)
来源出版物: IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING 卷: 10 期: 8 页: 3752-3767 DOI: 10.1109/JSTARS.2017.2700023 出版年: AUG 2017
摘要: Many state-of-the-art methods have been proposed for infrared small target detection. They work well on the images with homogeneous backgrounds and high-contrast targets. However, when facing highly heterogeneous backgrounds, they would not perform very well, mainly due to: 1) the existence of strong edges and other interfering components, 2) not utilizing the priors fully. Inspired by this, we propose a novel method to exploit both local and nonlocal priors simultaneously. First, we employ a new infrared patch-tensor (IPT) model to represent the image and preserve its spatial correlations. Exploiting the target sparse prior and background nonlocal self-correlation prior, the target-background separation is modeled as a robust low-rank tensor recovery problem. Moreover, with the help of the structure tensor and reweighted idea, we design an entrywise local-structure-adaptive and sparsity enhancing weight to replace the globally constant weighting parameter. The decomposition could be achieved via the elementwise reweighted higher order robust principal component analysis with an additional convergence condition according to the practical situation of target detection. Extensive experiments demonstrate that our model outperforms the other state-of-the-arts, in particular for the images with very dim targets and heavy clutters.
入藏号: WOS:000407706200028
ISSN: 1939-1404
eISSN: 2151-1535
第 71 条,共 255 条
标题: Ultrafast pulse generation with black phosphorus solution saturable absorber
作者: Li, L (Li, Lu); Wang, YG (Wang, Yonggang); Wang, X (Wang, Xi)
来源出版物: LASER PHYSICS 卷: 27 期: 8 文献号: 085104 DOI: 10.1088/1555-6611/aa7486 出版年: AUG 2017
摘要: The study presents the mode-locked Er-doped fiber (EDF) laser with a black phosphorus (BP) solution saturable absorber (SSA). The saturable absorber (SA) is fabricated based on a D-shaped fiber (DF) embedded in BP nanosheets N-Methylpyrrolidone solution. Such a BP solution method has the virtues of good antioxidant capacity, high heat dissipation and high damage threshold. This kind of SA shows a modulation depth of 7.75% and a nonsaturable loss of 10%. By employing the EDF-BP SSA, a repetition rate of 15.2 MHz mode-locked fiber laser is achieved. The pulse duration is 580 fs and the signal-to-noise ratio is 65 dB. The results indicate that the DF-BP solution can work as a potential SA for ultrafast nonlinear optics.
入藏号: WOS:000406850900001
ISSN: 1054-660X
eISSN: 1555-6611
第 72 条,共 255 条
标题: Nanosecond pulse signals restoration via stochastic resonance in the Fabry-Perot cavity with graphene
作者: Chang, Z (Chang, Zheng); Liu, HJ (Liu, Hongjun); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu); Han, J (Han, Jing)
来源出版物: EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS 卷: 79 期: 2 文献号: 20502 DOI: 10.1051/epjap/2017170145 出版年: AUG 2017
摘要: We investigate a technology for reconstructing nanosecond pulse noise hidden signals via stochastic resonance, which is based on optical bistability in the Fabry-Perot (F-P) cavity with graphene. The bistable properties are analyzed with different initial wavelengths and Fermi energies. The system is tunable and the bistable behavior of the output intensity can be accurately controlled to obtain a cross-correlation gain larger than 10 in a wide range of input signal-to-noise (SNR) ratio from 1:8 to 1:45. Meanwhile, the distortion of the output signal and the pulse tailing caused by the phase delay can be reduced to a negligible level. This work provides a potential method for detecting low-level or hidden pulse signals in various communication fields.
入藏号: WOS:000406057300002
ISSN: 1286-0042
eISSN: 1286-0050
第 73 条,共 255 条
标题: Enhancement of quantum-enhanced LADAR receiver in nonideal phase-sensitive amplification
作者: Zhang, S (Zhang, Shuan); Liu, HJ (Liu, Hongjun); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu); Han, J (Han, Jing)
来源出版物: EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS 卷: 79 期: 2 文献号: 20501 DOI: 10.1051/epjap/2017170113 出版年: AUG 2017
摘要: The phase-sensitive amplification (PSA) with an injected squeezed vacuum field is theoretically investigated in quantum-enhanced laser detection and ranging (LADAR) receiver. The theoretical model of the amplified process is derived to investigate the quantum fluctuations in detail. A new method of mitigating the unflat gain of nonideal PSA is proposed by adjusting the squeezed angle of the squeezed vacuum field. The simulation results indicate that signal-noise ratio (SNR) of system can be efficiently improved and close to the ideal case by this method. This research will provide an important potential in the applications of quantum-enhanced LADAR receiver.
入藏号: WOS:000406057300001
ISSN: 1286-0042
eISSN: 1286-0050
第 74 条,共 255 条
标题: A General Framework for Edited Video and Raw Video Summarization
作者: Li, XL (Li, Xuelong); Zhao, B (Zhao, Bin); Lu, XQ (Lu, Xiaoqiang)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 26 期: 8 页: 3652-3664 DOI: 10.1109/TIP.2017.2695887 出版年: AUG 2017
摘要: In this paper, we build a general summarization framework for both of edited video and raw video summarization. Overall, our work can be divided into three folds. 1) Four models are designed to capture the properties of video summaries, i.e., containing important people and objects (importance), representative to the video content (representativeness), no similar key-shots (diversity), and smoothness of the storyline (storyness). Specifically, these models are applicable to both edited videos and raw videos. 2) A comprehensive score function is built with the weighted combination of the aforementioned four models. Note that the weights of the four models in the score function, denoted as property-weight, are learned in a supervised manner. Besides, the property-weights are learned for edited videos and raw videos, respectively. 3) The training set is constructed with both edited videos and raw videos in order to make up the lack of training data. Particularly, each training video is equipped with a pair of mixing-coefficients, which can reduce the structure mess in the training set caused by the rough mixture. We test our framework on three data sets, including edited videos, short raw videos, and long raw videos. Experimental results have verified the effectiveness of the proposed framework.
入藏号: WOS:000403819200001
PubMed ID: 28436870
作者识别号:
作者        ResearcherID 号        ORCID 号
Lu, Xiaoqiang                  0000-0002-7037-5188
ISSN: 1057-7149
eISSN: 1941-0042
第 75 条,共 255 条
标题: Weakly Supervised Multimodal Kernel for Categorizing Aerial Photographs
作者: Xia, YJ (Xia, Yingjie); Zhang, LM (Zhang, Luming); Liu, ZG (Liu, Zhenguang); Nie, LQ (Nie, Liqiang); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 26 期: 8 页: 3748-3758 DOI: 10.1109/TIP.2016.2639438 出版年: AUG 2017
摘要: Accurately distinguishing aerial photographs from different categories is a promising technique in computer vision. It can facilitate a series of applications, such as video surveillance and vehicle navigation. In this paper, a new image kernel is proposed for effectively recognizing aerial photographs. The key is to encode high-level semantic cues into local image patches in a weakly supervised way, and integrate multimodal visual features using a newly developed hashing algorithm. The flowchart can be elaborated as follows. Given an aerial photo, we first extract a number of graphlets to describe its topological structure. For each graphlet, we utilize color and texture to capture its appearance, and a weakly supervised algorithm to capture its semantics. Thereafter, aerial photo categorization can be naturally formulated as graphlet-to-graphlet matching. As the number of graphlets from each aerial photo is huge, to accelerate matching, we present a hashing algorithm to seamlessly fuze the multiple visual features into binary codes. Finally, an image kernel is calculated by fast matching the binary codes corresponding to each graphlet. And a multi-class SVM is learned for aerial photo categorization. We demonstrate the advantage of our proposed model by comparing it with state-of-the-art image descriptors. Moreover, an in-depth study of the descriptiveness of the hash-based graphlet is presented.
入藏号: WOS:000403819200008
PubMed ID: 28113314
ISSN: 1057-7149
eISSN: 1941-0042
第 76 条,共 255 条
标题: Optofluidic in-fiber interferometer based on hollow optical fiber with two cores
作者: Yuan, TT (Yuan, Tingting); Yang, XH (Yang, Xinghua); Liu, ZH (Liu, Zhihai); Yang, J (Yang, Jun); Li, S (Li, Song); Kong, DP (Kong, Depeng); Qi, XX (Qi, Xiuxiu); Yu, WT (Yu, Wenting); Long, QL (Long, Qunlong); Yuan, LB (Yuan, Libo)
来源出版物: OPTICS EXPRESS 卷: 25 期: 15 页: 18205-18215 DOI: 10.1364/OE.25.018205 出版年: JUL 24 2017
摘要: We demonstrate a novel integrated optical fiber interferometer for in-fiber optofluidic detection. It is composed of a specially designed hollow optical fiber with a micro-channel and two cores. One core on the inner surface of the micro-channel is served as sensing arm and the other core in the annular cladding is served as reference arm. Fusion-and-tapering method is employed to couple light from a single mode fiber to the hollow optical fiber in this device. Sampling is realized by side opening a microhole on the surface of the hollow optical fiber. Under differential pressure between the end of the hollow fiber and the microhole, the liquids can form steady microflows in the micro-channel. Simultaneously, the interference spectrum of the interferometer device shifts with the variation of the concentration of the microfluid in the channel. The optofluidic in-fiber interferometer has a sensitivity of refractive index around 2508 nm/RIU for NaCl. For medicine concentration detection, its sensitivity is 0.076 nm/mmolL(-1) for ascorbic acid. Significantly, this work presents a compact microfluidic in-fiber interferometer with a micro-channel which can be integrated with chip devices without spatial optical coupling and without complex manufacturing procedure of the waveguide on the chips. (C) 2017 Optical Society of America
入藏号: WOS:000408584400123
PubMed ID: 28789310
作者识别号:
作者        ResearcherID 号        ORCID 号
Yang, jun         G-4446-2014         0000-0002-6805-4289
ISSN: 1094-4087
第 77 条,共 255 条
标题: Polarization control methods in structured illumination microscopy
作者: Zhao, TY (Zhao Tian-Yu); Zhou, X (Zhou Xing); Dan, D (Dan Dan); Qian, J (Qian Jia); Wang, ZJ (Wang Zhao-Jun); Lei, M (Lei Ming); Yao, BL (Yao Bao-Li)
来源出版物: ACTA PHYSICA SINICA 卷: 66 期: 14 特刊: SI 文献号: 148704 DOI: 10.7498/aps.66.148704 出版年: JUL 20 2017
摘要: Structured illumination microscopy (SIM) is one of the most promising super-resolution techniques, owing to its advantages of fast imaging speed and weak photo bleaching. The quality of the SIM image is greatly dependent on the contrast of the sinusoidal fringe illumination patterns. Low fringe contrast illumination will seriously affect the super-resolution result and lead to additional artifacts. The generation of fringe patterns with high contrast is the key requirement in hardware for the SIM technique. This can be done by the interference of two laser beams diffracted from the phase gratings addressed on a spatial light modulator. Meanwhile, for maximal interference contrast, precise polarization control to maintain s-polarization for different fringe orientations is critical. In this paper, we review several typical polarization control methods in SIM, and propose a new method by using a zero-order vortex half-wave retarder (VHR). Compared with the other methods, the presented VHR-based polarization control method is very efficient in terms of simple system configuration, ease of use, and high light energy utilization efficiency near to 100%.
入藏号: WOS:000408385100031
ISSN: 1000-3290
第 78 条,共 255 条
标题: Online and Efficient Fabrication of Helical Long-Period Fiber Gratings
作者: Ren, KL (Ren, Kaili); Ren, LY (Ren, Liyong); Liang, J (Liang, Jian); Kong, XD (Kong, Xudong); Ju, HJ (Ju, Haijuan); Wu, ZX (Wu, Zhaoxin)
来源出版物: IEEE PHOTONICS TECHNOLOGY LETTERS 卷: 29 期: 14 页: 1175-1178 DOI: 10.1109/LPT.2017.2711608 出版年: JUL 15 2017
摘要: By taking the advantage of inherent core-cladding eccentricities in standard single-mode fibers, in this letter, we propose and demonstrate an efficient method to fabricate helical long-period fiber gratings (H-LPFGs) by directly twisting fibers. In the fabrication process, we use a double-beam CO2 laser for heating the fiber stably and uniformly, together with an online scheme for monitoring the spectrum. Compared with other fabrication methods reported, the quality of H-LPFGs we fabricated is improved significantly, showing a high extinction ratio of over 30 dB and a low insertion loss of similar to 1 dB. Based on the fact that H-LPFGs with different pitches for specific mode couplings can be fabricated efficiently and controllably, to the best of our knowledge, we actually achieve H-LPFGs with the highest quality up to now, which may find important applications, such as filtering, sensing, and optical vortex generation.
入藏号: WOS:000404274300010
ISSN: 1041-1135
eISSN: 1941-0174
第 79 条,共 255 条
标题: Compact eccentric long period grating with improved sensitivity in low refractive index region
作者: Shen, FC (Shen, Fangcheng); Zhou, KM (Zhou, Kaiming); Gordon, N (Gordon, Neil); Zhang, L (Zhang, Lin); Shu, XW (Shu, Xuewen)
来源出版物: OPTICS EXPRESS 卷: 25 期: 14 页: 15729-15736 DOI: 10.1364/OE.25.015729 出版年: JUL 10 2017
摘要: We demonstrate a compact eccentric long period grating with enhanced sensitivity in low refractive index region. With a period designed at 15 mu m for coupling light to high order cladding modes, the grating is more sensitive to surrounding refractive index in low refractive index region. The intrinsically low coupling coefficients for those high order cladding modes are significantly improved with the eccentric localized inscription induced by the femtosecond laser. The fabricated grating is compact with a length of 4.05 mm, and exhibits an average sensitivity of similar to 505 nm/RIU in low refractive index region (1.3328-1.3544). The proposed principle can also work in other refractive index region with a proper choice of the resonant cladding modes. (C) 2017 Optical Society of America
入藏号: WOS:000407815100011
PubMed ID: 28789085
作者识别号:
作者        ResearcherID 号        ORCID 号
Gordon, Neil T                  0000-0002-1474-9739
ISSN: 1094-4087
第 80 条,共 255 条
标题: Deconvolution of spectral power distribution of high-power laser diode arrays
作者: Zhang, P (Zhang, Pu); Kim, DS (Kim, Dae-Suk); Han, B (Han, Bongtae)
来源出版物: APPLIED OPTICS 卷: 56 期: 20 页: 5590-5598 DOI: 10.1364/00.56.005590 出版年: JUL 10 2017
摘要: A novel method is proposed to predict the spectral power distributions (SPDs) of individual emitters in a high-power laser diode (LD) array. The proposed method deconvolutes the SPD of an LD array by taking into account the thermal cross-talk effect as well as the current competition effect. A complete analytical expression to deconvolute the SPD of an LD array is described. The expression contains four key parameters that are to be measured experimentally: (1) the normalized SPD of the central emitter, (2) the temperature coefficient of wavelength, (3) the current competition constant, and (4) the maximum power of the center emitter. The method is implemented with a commercial water-cooled high-power LD array. The SPD of the LD array predicted from the SPDs of individual emitters are compared with the experimentally measured SPD of the LD array. The results show excellent agreement in both shape and magnitude, which corroborates the validity of the proposed method. (C) 2017 Optical Society of America.
入藏号: WOS:000405353300001
PubMed ID: 29047699
作者识别号:
作者        ResearcherID 号        ORCID 号
Han, Bongtae                  0000-0003-3721-9738
ISSN: 1559-128X
eISSN: 2155-3165
第 81 条,共 255 条
标题: A diffuse plasma jet generated from the preexisting discharge filament at atmospheric pressure
作者: Li, J (Li, Jing); Xu, YG (Xu, Yonggang); Zhang, TY (Zhang, Tongyi); Tang, J (Tang, Jie); Wang, YS (Wang, Yishan); Zhao, W (Zhao, Wei); Duan, YX (Duan, Yixiang)
来源出版物: JOURNAL OF APPLIED PHYSICS 卷: 122 期: 1 文献号: 013301 DOI: 10.1063/1.4989975 出版年: JUL 7 2017
摘要: A diffuse plasma jet was realized by expanding the preexisting argon filamentary discharge into a diffuse one at atmospheric pressure. Examination of emission spectra from the plasma jet shows that the emission intensities of OH and Ar increase with the argon flow near the quartz tube nozzle, while the N-2 emission intensity first increases, then decreases, and finally approximately remains unchanged with the increase in the argon flow of interest. It is also found that with the argon flow set at 0.4 l/min,most of the reactive species are gathered close to the nozzle, the OH and Ar emission intensities decrease quickly after the plasma propagates out of the nozzle, but the N-2 emission is able to propagate over a larger distance. These distinct spectral emission features of OH, N-2, and Ar are attributed to the different generation and quenching mechanisms of their corresponding excited states, i.e., OH(A (2)Sigma(+)), N-2(C (3)Pi(mu)), and Ar(4p)/Ar(4s) in the argon plasma jet. Additionally, the formation of the diffuse plasma jet has been clarified by observing the discharge burning phase and solving the Poisson equation for the electric field distribution in an argon cylindrical dielectric-barrier discharge. The filamentary discharge deposits charged particles onto the dielectric. The positive surface charges in the positive half cycle induce a relatively high field in the local region close to the dielectric. The relatively high field and the high pre-ionization in this local region play a key role in initiating the diffuse positive corona. Published by AIP Publishing.
入藏号: WOS:000405084900008
ISSN: 0021-8979
eISSN: 1089-7550
第 82 条,共 255 条
标题: AID: A Benchmark Data Set for Performance Evaluation of Aerial Scene Classification
作者: Xia, GS (Xia, Gui-Song); Hu, JW (Hu, Jingwen); Hu, F (Hu, Fan); Shi, BG (Shi, Baoguang); Bai, X (Bai, Xiang); Zhong, YF (Zhong, Yanfei); Zhang, LP (Zhang, Liangpei); Lu, XQ (Lu, Xiaoqiang)
来源出版物: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 卷: 55 期: 7 页: 3965-3981 DOI: 10.1109/TGRS.2017.2685945 出版年: JUL 2017
摘要: Aerial scene classification, which aims to automatically label an aerial image with a specific semantic category, is a fundamental problem for understanding high-resolution remote sensing imagery. In recent years, it has become an active task in the remote sensing area, and numerous algorithms have been proposed for this task, including many machine learning and data-driven approaches. However, the existing data sets for aerial scene classification, such as UC-Merced data set and WHU-RS19, contain relatively small sizes, and the results on them are already saturated. This largely limits the development of scene classification algorithms. This paper describes the Aerial Image data set (AID): a large-scale data set for aerial scene classification. The goal of AID is to advance the state of the arts in scene classification of remote sensing images. For creating AID, we collect and annotate more than 10 000 aerial scene images. In addition, a comprehensive review of the existing aerial scene classification techniques as well as recent widely used deep learning methods is given. Finally, we provide a performance analysis of typical aerial scene classification and deep learning approaches on AID, which can be served as the baseline results on this benchmark.
入藏号: WOS:000404300900027
作者识别号:
作者        ResearcherID 号        ORCID 号
Lu, Xiaoqiang                  0000-0002-7037-5188
Xia, Gui-Song                  0000-0001-7660-6090
ISSN: 0196-2892
eISSN: 1558-0644
第 83 条,共 255 条
标题: Improved multiple circular array configuration for sparse aperture optical imaging systems
作者: Liu, AM (Liu, Aimin); Gao, LM (Gao, Limin); Xiao, MS (Xiao, Maosen)
来源出版物: OPTICAL ENGINEERING 卷: 56 期: 7 文献号: 073109 DOI: 10.1117/1.OE.56.7.073109 出版年: JUL 2017
摘要: An improved multiple circular array (MCA) configuration is proposed for sparse aperture (SA) optical imaging systems. Using genetic algorithms, the practical cutoff frequency (PCOF), based on the modulation transfer function for the array, is selected as the fitness function. Moreover, the parameters, such as diameters of aperture sets, spacing between the aperture sets, and relative rotation angles between aperture sets on different concentric circles, are calculated. Improved MCA configurations, with aperture numbers of 6, 9, 12, 10, 15, 11, and 13, are given. Golay arrays, MCAs, a single annular aperture, and improved arrays with the same fill factor are compared. The results show that the improved array has highest PCOF of all the SA arrays, smoother coverage in Fourier space, and better midfrequency contrast than MCAs. Consequently, the improved array is a promising aperture configuration that can approximate a single annular aperture. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000407370200022
ISSN: 0091-3286
eISSN: 1560-2303
第 84 条,共 255 条
标题: Repetition Rate Multiplication Pulsed Laser Source Based on a Microring Resonator
作者: Wang, WQ (Wang, Weiqiang); Zhang, WF (Zhang, Wenfu); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Yang, QH (Yang, Qinghua); Wang, LR (Wang, Leiran); Hu, XH (Hu, Xiaohong); Wang, L (Wang, Lei); Wang, GX (Wang, Guoxi); Wang, YS (Wang, Yishan); Zhao, W (Zhao, Wei)
来源出版物: ACS PHOTONICS 卷: 4 期: 7 页: 1677-1683 DOI: 10.1021/acsphotonics.7b00129 出版年: JUL 2017
摘要: We demonstrate a stable high-Q microring resonator (MRR)-based pulsed laser source with adjustable repetition rate from 49 to 735 GHz, corresponds to repetition rate multiplication of up to 15X the free spectral range (FSR) of the MRR. The repetition rate multiplication is realized by temporal multiplexing multiple pulses in the MRR through simply tuning of the fiber cavity length. Thus, the repetition rate of the pulsed laser source breaks the frequency limitation of the previous dissipative four wave mixing based mode locked lasers whose repetition rate is equal to the FSR of the built in comb filter. This high quality chip-based repetition rate multiplicable pulsed laser source is an effective approach to on-chip ultrahigh speed optical clock frequency multiplication systems.
入藏号: WOS:000406174600015
作者识别号:
作者        ResearcherID 号        ORCID 号
CHU, Sai Tak                  0000-0001-8263-8507
ISSN: 2330-4022
第 85 条,共 255 条
标题: Bifurcated overtones of one-way localized Fabry-Perot resonances in parity-time symmetric optical lattices
作者: Gaafer, FN (Gaafer, Fatma Nafaa); Shen, YX (Shen, Yaxi); Peng, YG (Peng, Yugui); Wu, AM (Wu, Aimin); Zhang, P (Zhang, Peng); Zhu, XF (Zhu, Xuefeng)
来源出版物: CHINESE PHYSICS B 卷: 26 期: 7 文献号: 074218 DOI: 10.1088/1674-1056/26/7/074218 出版年: JUL 2017
摘要: Since the first observation of parity-time (PT) symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, which turns PT-symmetric optics into a hotspot in research. Here, we report on the one-way localized Fabry-Perot (FP) resonance, where a well-designed PT optical resonator may operate at exceptional points with bidirectional transparency but unidirectional field localization. Overtones of such one-way localized FP resonance can be classified into a blue shifted branch and a red shifted branch. Therefore, the fundamental resonant frequency is not the lowest one. We find that the spatial field distributions of the overtones at the same absolute order are almost the same, even though their frequencies are quite different.
入藏号: WOS:000405130100018
ISSN: 1674-1056
eISSN: 1741-4199
第 86 条,共 255 条
标题: Spatiotemporal evolution of continuous-wave field and dark soliton formation in a microcavity with normal dispersion
作者: Hu, XH (Hu, Xiaohong); Zhang, W (Zhang, Wei); Liu, YS (Liu, Yuanshan); Feng, Y (Feng, Ye); Zhang, WF (Zhang, Wenfu); Wang, LR (Wang, Leiran); Wang, YS (Wang, Yishan); Zhao, W (Zhao, Wei)
来源出版物: CHINESE PHYSICS B 卷: 26 期: 7 文献号: 074216 DOI: 10.1088/1674-1056/26/7/074216 出版年: JUL 2017
摘要: Stable dark soliton and dark pulse formation in normally dispersive and red-detuned microcavities are investigated by numerically solving the normalized Lugiato-Lefever equation. The soliton essence is proved by fitting the calculated field intensity profile with the analytical formula of a dark soliton. Meanwhile, we find that a dark soliton can be generated either from the nonlinear evolution of an optical shock wave or narrowing of a locally broad dark pulse with smoother fronts. Explicit analytical expression is obtained to describe the oscillatory fronts of the optical shock wave. Furthermore, from the calculation results, we show that for smaller frequency detunings, e.g., alpha < 3, in addition to the dark soliton formation, a single dark pulse with an oscillatory dip can also arise and propagate stably in the microcavity under proper pump detuning and pump strength combination. The existence region together with various field intensity profiles and the corresponding spectra of single dark pulse are demonstrated.
入藏号: WOS:000405130100016
ISSN: 1674-1056
eISSN: 1741-4199
第 87 条,共 255 条
标题: Magneto-optical effects of Ge-Ga-Sb(In)-S chalcogenide glasses with diamagnetic responses
作者: Chen, G (Chen, Gang); Xu, YT (Xu, Yantao); Guo, HT (Guo, Haitao); Cui, XX (Cui, Xiaoxia); Wang, PF (Wang, Pengfei); Lu, M (Lu, Min); Xiao, XS (Xiao, Xusheng); Guo, Q (Guo, Quan); Peng, B (Peng, Bo)
来源出版物: JOURNAL OF THE AMERICAN CERAMIC SOCIETY 卷: 100 期: 7 页: 2914-2920 DOI: 10.1111/jace.14808 出版年: JUL 2017
摘要: The Faraday effects of Ge-Ga-Sb(In)-S serial chalcogenide glasses were investigated at the wavelengths of 635, 808, 980, and 1319 nm, respectively. The compositional dependences were analyzed and associated influencing factors including the absorption edge, the concentration of Sb3+/In3+ ions, and the wavelength dispersion of refraction index were discussed. 80GeS(2)20Sb(2)S(3) composition glass was found to have the largest Verdet constant (V=0.253, 0.219, 0.149, and 0.065 minG(-1)cm(-1) for wavelengths 635, 808, 980, and 1319 nm, respectively) in these glasses, which is larger than that of commercial diamagnetic glasses (Schott, SF 6, V=0.069 minG(-1)cm(-1)@633 nm, for example). Sb3+ ions with high polarizability possessing s(2)-sp electron jumps involving (S0P1)-S-1-P-1, P-3(0,1,2) transitions are responsible for large Verdet constant, and Becquerel rule is proved to be an effective guidance for estimating the Verdet constant and further optimizing the compositions in chalcogenide glasses.
入藏号: WOS:000404730100017
ISSN: 0002-7820
eISSN: 1551-2916
第 88 条,共 255 条
标题: Nonnegative Discriminant Matrix Factorization
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 CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 卷: 27 期: 7 页: 1392-1405 DOI: 10.1109/TCSVT.2016.2539779 出版年: JUL 2017
摘要: Nonnegative matrix factorization (NMF), which aims at obtaining the nonnegative low-dimensional representation of data, has received wide attention. To obtain more effective nonnegative discriminant bases from the original NMF, in this paper, a novel method called nonnegative discriminant matrix factorization (NDMF) is proposed for image classification. NDMF integrates the nonnegative constraint, orthogonality, and discriminant information in the objective function. NDMF considers the incoherent information of both factors in standard NMF and is proposed to enhance the discriminant ability of the learned base matrix. NDMF projects the low-dimensional representation of the subspace of the base matrix to regularize the NMF for discriminant subspace learning. Based on the Euclidean distance metric and the generalized Kullback-Leibler (KL) divergence, two kinds of iterative algorithms are presented to solve the optimization problem. The between-and within-class scatter matrices are divided into positive and negative parts for the update rules and the proofs of the convergence are also presented. Extensive experimental results demonstrate the effectiveness of the proposed method in comparison with the state-of-the-art discriminant NMF algorithms.
入藏号: WOS:000405039200002
ISSN: 1051-8215
eISSN: 1558-2205
第 89 条,共 255 条
标题: Field-induced lifetime enhancement of photorefractive gratings in a Mn:Fe:KTN crystal
作者: Lu, QN (Lu, Qieni); Li, BH (Li, Bihua); Li, Z (Li, Zhen); Ge, BZ (Ge, Baozhen)
来源出版物: OPTICS LETTERS 卷: 42 期: 13 页: 2407-2410 DOI: 10.1364/OL.42.002407 出版年: JUL 1 2017
摘要: We report the lifetime enhancement of light-induced refractive index grating by applying a bias field during writing. In comparison with the lifetime of about 10 hours of the photorefractive grating prepared without a bias field, the lifetime of the grating with a 4 kV/cm bias field can be prolonged to 7.5 years, which is obtained from the dynamic behavior of grating visualized and monitored with digital holographic microscopy. The higher the bias field is applied, the longer the dark decay time of grating can be achieved. The enhanced lifetime of phase grating is attributed to polar nanoregions oriented by external field. This effect is of great significance for electro-holographic device applications. (C) 2017 Optical Society of America
入藏号: WOS:000404743500002
PubMed ID: 28957245
ISSN: 0146-9592
eISSN: 1539-4794
第 90 条,共 255 条
标题: Double line and tubular depressed cladding waveguides written by femtosecond laser irradiation in PTR glass
作者: Zhang, YJ (Zhang, Y. J.); Zhang, GD (Zhang, G. D.); Bai, J (Bai, J.); Chen, CL (Chen, C. L.); Stoian, R (Stoian, R.); Cheng, GH (Cheng, G. H.)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 7 期: 7 页: 2626-2635 DOI: 10.1364/OME.7.002626 出版年: JUL 1 2017
摘要: Depressed cladding concepts such as double line depressed index and tubular low index cladding waveguide structures were fabricated in bulk photo-thermo-refractive glass using femtosecond laser pulses. Effects of the writing laser power, waveguide geometrical structures and heat treatment on the light guiding properties were investigated. The results show that depressed cladding tubular waveguide design exhibits better guiding performances than double line waveguides in PTR glass. For the tubular cladding waveguide, single and multimode fields can be obtained for a wide processing parameter window. The simulations agree well with the experiment results. Moreover, the normalized frequency can be tuned and the quality of the depressed cladding tubular waveguide can be improved by eliminating uneven stress distribution after heat treatment. (C) 2017 Optical Society of America.
入藏号: WOS:000404735600048
作者识别号:
作者        ResearcherID 号        ORCID 号
Stoian, Razvan                  0000-0003-2107-9515
ISSN: 2159-3930
第 91 条,共 255 条
标题: Adaptive 3D shape context representation for motion trajectory classification
作者: Liu, WH (Liu, Weihua); Li, ZH (Li, Zuhe); Zhang, G (Zhang, Geng); Zhang, Z (Zhang, Zhong)
来源出版物: MULTIMEDIA TOOLS AND APPLICATIONS 卷: 76 期: 14 页: 15413-15434 DOI: 10.1007/s11042-016-3841-0 出版年: JUL 2017
摘要: The measurement of similarity between two motion trajectories is one of the fundamental task for motion analysis, perception and recognition. Previous research focus on 2D trajectory similarity measurement. With the advent of 3D sensors, it is possible to collect large amounts of 3D trajectory data for more precise motion representation. As trajectories in 3D space may often exhibit a similar motion pattern but may differ in location, orientation, scale, and appearance variations, the trajectory descriptor must be invariant to these degrees of freedom. Shape context is one of the rich local shape descriptors can be used to represent the trajectory in 2D space, however, rarely applied in the 3D motion trajectory recognition field. To handle 3D data, in this paper, we first naturally extend the shape context into the spatiotemporal domain by adopting a spherical neighborhood, and named it 3D Shape Context(3DSC). To achieve better global invariant on trajectories classification, the adaptive outer radius of 3DSC for extracting 3D Shape Context feature is proposed. The advantages of our proposed 3D shape context are: (1) It is invariant to motion trajectories translation and scale in the spatiotemporal domain; (2) It contains the whole trajectory points in the 3DSC ball volume, thus can achieve global information representation and is good for solving sub-trajectories problem; (3) It is insensitive to the appearance variations in the identical meaning trajectories, meanwhile, can greatly discriminate the distinct meaning trajectories. In trajectory recognition phase, we consider a feature-to-feature alignment between motion trajectories based on dynamic time warping and then use the one nearest neighbor (1NN) classifier for final accuracy evaluation. We test the performance of proposed 3D SC-DTW on UCI ASL large dataset, Digital hand dataset and the experimental results demonstrate the effectiveness of our method.
入藏号: WOS:000404609900010
ISSN: 1380-7501
eISSN: 1573-7721
第 92 条,共 255 条
标题: Modeling Disease Progression via Multisource Multitask Learners: A Case Study With Alzheimer's Disease
作者: Nie, LQ (Nie, Liqiang); Zhang, LM (Zhang, Luming); Meng, L (Meng, Lei); Song, XM (Song, Xuemeng); Chang, XJ (Chang, Xiaojun); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 28 期: 7 页: 1508-1519 DOI: 10.1109/TNNLS.2016.2520964 出版年: JUL 2017
摘要: Understanding the progression of chronic diseases can empower the sufferers in taking proactive care. To predict the disease status in the future time points, various machine learning approaches have been proposed. However, a few of them jointly consider the dual heterogeneities of chronic disease progression. In particular, the predicting task at each time point has features from multiple sources, and multiple tasks are related to each other in chronological order. To tackle this problem, we propose a novel and unified scheme to coregularize the prior knowledge of source consistency and temporal smoothness. We theoretically prove that our proposed model is a linear model. Before training our model, we adopt the matrix factorization approach to address the data missing problem. Extensive evaluations on real-world Alzheimer's disease data set have demonstrated the effectiveness and efficiency of our model. It is worth mentioning that our model is generally applicable to a rich range of chronic diseases.
入藏号: WOS:000404048300002
PubMed ID: 26929064
ISSN: 2162-237X
eISSN: 2162-2388
第 93 条,共 255 条
标题: Highly Strain and Bending Sensitive Microtapered Long-Period Fiber Gratings
作者: Ren, KL (Ren, Kaili); Ren, LY (Ren, Liyong); Liang, J (Liang, Jian); Kong, XD (Kong, Xudong); Ju, HJ (Ju, Haijuan); Wu, ZX (Wu, Zhaoxin)
来源出版物: IEEE PHOTONICS TECHNOLOGY LETTERS 卷: 29 期: 13 页: 1085-1088 DOI: 10.1109/LPT.2017.2702573 出版年: JUL 1 2017
摘要: A microtapered long-period fiber grating (MTLPFG) is fabricated successfully by periodically tapering a standard single-mode fiber with CO2 laser heating source. This can be done by taking advantage of that the effective index difference between the core mode and the cladding modes is changed periodically during microtapering. High fabrication reproducibility and MTLPFGs quality can be achieved by this CO2 laser-heater-based fabrication scheme. In addition, the strain, bending, and liquid-level sensing characteristics of the MTLPFGs are investigated experimentally. Compared with the conventional long-period fiber gratings, it is found that the strain and bending sensitivities of fabricated MTLPFGs are improved by factors of about 10 and 5, respectively. Considering the simple and flexible fabrication process as well as the high quality and sensitivity of fabricated MTLPFGs, we believe that this may offer a simpler and alternative choice to current filters or sensing applications.
入藏号: WOS:000403822000008
ISSN: 1041-1135
eISSN: 1941-0174
第 94 条,共 255 条
标题: A new compressive sensing video coding framework based on Gaussian mixture model
作者: Li, XW (Li, Xiangwei); Lan, XG (Lan, Xuguang); Yang, M (Yang, Meng); Xue, JR (Xue, Jianru); Zheng, NN (Zheng, Nanning)
来源出版物: SIGNAL PROCESSING-IMAGE COMMUNICATION 卷: 55 页: 66-79 DOI: 10.1016/j.image.2017.03.009 出版年: JUL 2017
摘要: In this paper, we specifically design an efficient compressive sensing video (CSV) coding framework for the CSV system, by considering the distribution characteristics of the CSV frame. To explore the spatial redundancy of the CSV, the CSV frame is first divided into blocks and each block is modeled by a Gaussian mixture model (GMM), and then it is compressed by a product vector quantization. We further explore the temporal redundancy of the CSV by encoding the adjacent CSV frames by the differential pulse code modulation technique and the arithmetic encoding technique. Experiment results show that the proposed CSV coding solution maintains low coding complexity, which is required by the CSV system. Meanwhile, it achieves significant BD-PSNR improvement by about 7.13-11.41 dB (or equivalently 51.23-66.96% bitrate savings) compared with four existing video coding solutions, which also have low computational complexity and suit for the CSV system.
入藏号: WOS:000402351000007
ISSN: 0923-5965
eISSN: 1879-2677
第 95 条,共 255 条
标题: Learning Multilayer Channel Features for Pedestrian Detection
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: 26 期: 7 页: 3210-3220 DOI: 10.1109/TIP.2017.2694224 出版年: JUL 2017
摘要: Pedestrian detection based on the combination of convolutional neural network (CNN) and traditional handcrafted features (i.e., HOG+LUV) has achieved great success. In general, HOG+LUV are used to generate the candidate proposals and then CNN classifies these proposals. Despite its success, there is still room for improvement. For example, CNN classifies these proposals by the fully connected layer features, while proposal scores and the features in the inner-layers of CNN are ignored. In this paper, we propose a unifying framework called multi-layer channel features (MCF) to overcome the drawback. It first integrates HOG+LUV with each layer of CNN into a multi-layer image channels. Based on the multi-layer image channels, a multi-stage cascade AdaBoost is then learned. The weak classifiers in each stage of the multi-stage cascade are learned from the image channels of corresponding layer. Experiments on Caltech data set, INRIA data set, ETH data set, TUD-Brussels data set, and KITTI data set are conducted. With more abundant features, an MCF achieves the state of the art on Caltech pedestrian data set (i.e., 10.40% miss rate). Using new and accurate annotations, an MCF achieves 7.98% miss rate. As many non-pedestrian detection windows can be quickly rejected by the first few stages, it accelerates detection speed by 1.43 times. By eliminating the highly overlapped detection windows with lower scores after the first stage, it is 4.07 times faster than negligible performance loss.
入藏号: WOS:000401297400010
PubMed ID: 28459686
ISSN: 1057-7149
eISSN: 1941-0042
第 96 条,共 255 条
标题: Self-assembled high-performance graphene oxide fibers using ionic liquid as coagulating agent
作者: Zhang, D (Zhang, Dong); Peng, L (Peng, Li); Shi, NE (Shi, Naien); Yu, YH (Yu, Youhai); Min, YG (Min, Yonggang); Epstein, AJ (Epstein, Arthur J.)
来源出版物: JOURNAL OF MATERIALS SCIENCE 卷: 52 期: 13 页: 7698-7708 DOI: 10.1007/s10853-017-1050-5 出版年: JUL 2017
摘要: An efficient strategy for fabricating high-performance GO fibers (GFs) by using ionic liquids as coagulating agent via wet-spinning technique was reported for the first time. The interactions between the functional groups of the GO sheets and the ionic liquids cations could be tuned by choosing ionic liquids cations with designed structure, yielding GFs with varied mechanical properties. No organic solvent or postdrawing processes involved makes this process green and facile.
入藏号: WOS:000399422000007
作者识别号:
作者        ResearcherID 号        ORCID 号
SHI, Naien         B-5049-2011         
ISSN: 0022-2461
eISSN: 1573-4803
第 97 条,共 255 条
标题: Theoretical study on core-mode to radiation-mode coupling in chiral fiber long-period gratings
作者: Ren, KL (Ren, Kaili); Ren, LY (Ren, Liyong); Wang, YL (Wang, Yingli); Lin, X (Lin, Xiao); Liang, J (Liang, Jian); Xu, YP (Xu, Yiping); Ju, HJ (Ju, Haijuan)
来源出版物: OPTICS AND LASER TECHNOLOGY 卷: 92 页: 150-155 DOI: 10.1016/j.opflastec.2017.01.022 出版年: JUL 1 2017
摘要: The chiral fiber long-period gratings (CLPGs) could be fabricated by twisting a high-birefringence (Hi-Bi) fiber. However, when it is immersed into a material whose refractive index (RI) is higher than that of the cladding, there exists a complicated coupling between the core modes and the radiation ones. In this paper, for the first time to our knowledge, we theoretically investigate the mode coupling characteristics in such a CLPG. It is found that, owing to a strong mode transfer from the co-handed core mode to continuous radiation ones under the phase-matching condition, the CLPG can be regarded as a broadband circular polarizer since only the cross handed circularly polarized light is left when a linearly polarized light is injected. Furthermore, the influence of the RI of the surrounding medium on the bandwidth and extinction ratio of this circular polarizer is investigated in detail. As a result, a broadband all-fiber circular polarizer can be constructed. Considering its simple configuration, it might have some potential applications, such as filters, broadband polarizers, and sensors.
入藏号: WOS:000397367300023
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 98 条,共 255 条
标题: Passively harmonic mode-locked fiber laser based on ReS2 saturable absorber
作者: Lu, FF (Lu, Feifei)
来源出版物: MODERN PHYSICS LETTERS B 卷: 31 期: 18 文献号: 1750206 DOI: 10.1142/S0217984917502062 出版年: JUN 30 2017
摘要: We demonstrate the generation of harmonic mode-locking (HML) in an erbium-doped fiber laser with a microfiber-based rhenium disulfide (ReS2) saturable absorber (SA). Taking advantages of both saturable absorption and large third-order nonlinear effect of ReS2, HML pulse with 318.5 MHz repetition rate can be obtained, corresponding to 168th harmonic of fundamental repetition frequency of 1.896 MHz. When the pump power is increased gradually, the pulse interval remains constant, while the output power increases linearly. At the pump power of 450 mW, the output power is similar to 12 mW. The proposed high-repetition-rate pulse lasers would attract considerable attention due to its potential applications in soliton communications and frequency combs.
入藏号: WOS:000404895800009
ISSN: 0217-9849
eISSN: 1793-6640
第 99 条,共 255 条
标题: Li3PO4-added garnet-type Li6.5La3Zr1.5Ta0.5O12 for Li-dendrite suppression
作者: Xu, BY (Xu, Biyi); Li, WL (Li, Wenlong); Duan, HN (Duan, Huanan); Wang, HJ (Wang, Haojing); Guo, YP (Guo, Yiping); Li, H (Li, Hua); Liu, HZ (Liu, Hezhou)
来源出版物: JOURNAL OF POWER SOURCES 卷: 354 页: 68-73 DOI: 10.1016/j.jpowsour.2017.04.026 出版年: JUN 30 2017
摘要: This paper proposes a strategy to stabilize the garnet/Li interface by introducing Li3PO4 as an additive in garnet-type Li6.5La3Zr1.5Ta0.5O12. The Li3PO4-added Li6.5La3Zr1.5Ta0.5O12 electrolyte exhibits a room temperature Li-ion conductivity of 1.4 x 10(-4) S cm(-1), which is less than that of the Li3PO4-free counterparts (4.6 x 10(-4) S cm(-1)). However, the presence of Li3PO4 improves the interfacial compatibility and suppresses Li-dendrite formation during Li-metal plating/stripping. The symmetric Li/garnet/Li cells with Li3PO4-added Li6.3La3Zr1.5Ta0.5O12 have been successfully cycled at a current density of 0.1 mA cm(-2) at 60 degrees C for 60 h; on contrast, the control cells with Li3PO4-free Li6.5La3Zr1.5Ta0.5O12 display noisy potential with large voltage polarization and get short-circuited completely after 33-h cycling under the same operating condition. The outstanding interface stability can be attributed to the in situ reaction of the Li flux with Li3PO4 to form a self-limiting and ion-conducting interphase, Li3P, which is confirmed experimentally. (C) 2017 Elsevier B.V. All rights reserved.
入藏号: WOS:000401686100009
作者识别号:
作者        ResearcherID 号        ORCID 号
Duan, Huanan                  0000-0003-3052-3905
ISSN: 0378-7753
eISSN: 1873-2755
第 100 条,共 255 条
标题: On-chip generation of high-dimensional entangled quantum states and their coherent control
作者: Kues, M (Kues, Michael); Reimer, C (Reimer, Christian); Roztocki, P (Roztocki, Piotr); Cortes, LR (Cortes, Luis Romero); Sciara, S (Sciara, Stefania); Wetzel, B (Wetzel, Benjamin); Zhang, YB (Zhang, Yanbing); Cino, A (Cino, Alfonso); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Moss, DJ (Moss, David J.); Caspani, L (Caspani, Lucia); Azana, J (Azana, Jose); Morandotti, R (Morandotti, Roberto)
来源出版物: NATURE 卷: 546 期: 7660 页: 622-+ DOI: 10.1038/nature22986 出版年: JUN 29 2017
摘要: Optical quantum states based on entangled photons are essential for solving questions in fundamental physics and are at the heart of quantum information science(1). Specifically, the realization of high-dimensional states (D-level quantum systems, that is, qudits, with D > 2) and their control are necessary for fundamental investigations of quantum mechanics(2), for increasing the sensitivity of quantum imaging schemes(3), for improving the robustness and key rate of quantum communication protocols(4), for enabling a richer variety of quantum simulations(5), and for achieving more efficient and error-tolerant quantum computation(6). Integrated photonics has recently become a leading platform for the compact, cost-efficient, and stable generation and processing of non-classical optical states(7). However, so far, integrated entangled quantum sources have been limited to qubits (D = 2)(8-11). Here we demonstrate on-chip generation of entangled qudit states, where the photons are created in a coherent superposition of multiple high-purity frequency modes. In particular, we confirm the realization of a quantum system with at least one hundred dimensions, formed by two entangled qudits with D = 10. Furthermore, using state-of-the-art, yet off-the-shelf telecommunications components, we introduce a coherent manipulation platform with which to control frequency-entangled states, capable of performing deterministic high-dimensional gate operations. We validate this platform by measuring Bell inequality violations and performing quantum state tomography. Our work enables the generation and processing of high-dimensional quantum states in a single spatial mode.
入藏号: WOS:000404332000041
PubMed ID: 28658228
作者识别号:
作者        ResearcherID 号        ORCID 号
CHU, Sai Tak                  0000-0001-8263-8507
Caspani, Lucia                  0000-0003-2711-0448
moss, david                  0000-0001-5195-1744
ISSN: 0028-0836
eISSN: 1476-4687


第 101 条,共 255 条
标题: Embedded nanogratings in bulk fused silica under non-diffractive Bessel ultrafast laser irradiation
作者: Cheng, G (Cheng, G.); Rudenko, A (Rudenko, A.); D'Amico, C (D'Amico, C.); Itina, TE (Itina, T. E.); Colombier, JP (Colombier, J. P.); Stoian, R (Stoian, R.)
来源出版物: APPLIED PHYSICS LETTERS 卷: 110 期: 26 文献号: 261901 DOI: 10.1063/1.4987139 出版年: JUN 26 2017
摘要: We report the formation of embedded nanogratings in bulk fused silica under quasi- stationary field patterns generated by ultrashort laser pulses in nondiffractive modes. The zero- order Bessel beam consists of almost non- propagative light pulses distributed along a narrow micron- sized channel sustained over a large non- diffracting length. Upon multipulse irradiation, a regular pattern of nanoplanes is formed across the channel, spaced at approximately lambda/2n. Applying an electromagnetic scattering model [A. Rudenko et al., Phys. Rev. B 93, 075427 (2016)], we associate the formation of nanogratings with multiple scattering from randomly distributed scattering centers created by laser light. Constructive interference between the scattered wavelets leads to periodic excitation enhancement without requiring explicit synchronism conditions. Permanent material modifications are found whenever the local carrier densities are maximized towards the critical value. Multiple periodicities are predicted, either implicitly related to the coherent electromagnetic interaction or due to periodic field depletion and photon replenishment. Published by AIP Publishing.
入藏号: WOS:000404627700016
作者识别号:
作者        ResearcherID 号        ORCID 号
Colombier, Jean-Philippe         B-8884-2012         0000-0001-8462-7019
ITINA, Tatiana                  0000-0001-7117-8699
ISSN: 0003-6951
eISSN: 1077-3118
第 102 条,共 255 条
标题: Graphene on meta-surface for super-resolution optical imaging with a sub-10 nm resolution
作者: Cao, S (Cao, Shun); Wang, TS (Wang, Taisheng); Sun, Q (Sun, Qiang); Hu, BL (Hu, Bingliang); Levy, U (Levy, Uriel); Yu, WX (Yu, Weixing)
来源出版物: OPTICS EXPRESS 卷: 25 期: 13 页: 14494-14503 DOI: 10.1364/OE.25.014494 出版年: JUN 26 2017
摘要: Nowadays, wide-field of view plasmonic structured illumination method (WFPSIM) has been extensively studied and experimentally demonstrated in biological researches. Normally, noble metal structures are used in traditional WFPSIM to support ultrahigh wave-vector of SPs and an imaging resolution enhancement of 3-4 folds can be achieved. To further improve the imaging resolution of WFPSIM, we hereby propose a widefield optical nanoimaging method based on a hybrid graphene on meta-surface structure (GMS) model. It is found that an ultra-high wave-vector of graphene SPs can be excited by a metallic nanoslits array with localized surface plasmon enhancement. As a result, a standing wave surface plasmons (SW-SPs) interference pattern with a period of 11 nm for a 980 nm incident wavelength can be obtained. The potential application of the GMS for wide-field of view super-resolution imaging is discussed followed by simulation results which show that an imaging resolution of sub-10 nm can be achieved. The demonstrated method paves a new route for wide field optical nanoimaging, with applications e.g. in biological research to study biological processes occurring in cell membrane. (C) 2017 Optical Society of America
入藏号: WOS:000404189800054
PubMed ID: 28789035
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: 1094-4087
第 103 条,共 255 条
标题: In-situ growth amorphous carbon nanotube on silicon particles as lithium-ion battery anode materials
作者: Zhao, TK (Zhao, Tingkai); She, SF (She, Shengfei); Ji, XL (Ji, Xianglin); Jin, WB (Jin, Wenbo); Dang, AL (Dang, Alei); Li, H (Li, Hao); Li, TH (Li, Tiehu); Shang, SM (Shang, Songmin); Zhou, ZF (Zhou, Zhongfu)
来源出版物: JOURNAL OF ALLOYS AND COMPOUNDS 卷: 708 页: 500-507 DOI: 10.1016/j.jallcom.2017.03.019 出版年: JUN 25 2017
摘要: A novel silicon core/amorphous carbon nanotube (ACNT) shell composite that can be used as lithium-ion batteries anode material was in-situ synthesized in the chemical vapor deposition (CVD) growth process. The hypothesized core/shell structure was evidenced by SEM/TEM/XRD, suggesting that the ACNTs composed of carbon clusters with short-range order and long-range disorder were successfully deposited onto the surface of the silicon particles. This Si/ACNT composite delivered a high capacity of 1496 mAh g(-1) at a current density of 100 mA g(-1), and a superior cycling stability with 80% capacity retention after 300 cycles. This observed specific capacity improvement of Si/ACNT composite is likely attributed to the formed three-dimensional conductive networks between silicon particles and interwoven ACNTs in the composite. (c) 2017 Elsevier B.V. All rights reserved.
入藏号: WOS:000400713300067
作者识别号:
作者        ResearcherID 号        ORCID 号
SHANG, Songmin         P-6494-2017         0000-0002-6812-7652
ISSN: 0925-8388
eISSN: 1873-4669
第 104 条,共 255 条
标题: On-Chip Router Elements Based on Silicon Hybrid Plasmonic Waveguide
作者: Ge, ZQ (Ge, Zhiqiang); Zhang, LX (Zhang, Lingxuan); Wang, GX (Wang, Guoxi); Zhang, WF (Zhang, Wenfu); Liu, ML (Liu, Mulong); Li, SQ (Li, Siqi); Wang, LR (Wang, Leiran); Sun, QB (Sun, Qibing); Ren, WZ (Ren, Wenzhen); Si, JH (Si, Jinhai); Zhao, W (Zhao, Wei)
来源出版物: IEEE PHOTONICS TECHNOLOGY LETTERS 卷: 29 期: 12 页: 952-955 DOI: 10.1109/LPT.2017.2695081 出版年: JUN 15 2017
摘要: We have proposed and investigated micro-ring add-drop switch and M-Z interferometric element for on-chip router applications based on silicon hybrid plasmonic waveguide. The proposed silicon hybrid plasmonic waveguide possesses lower propagation loss compared with conventional plasmonic metal-insulator-metal waveguide. By employing this low loss waveguide, it is found that the proposed ring add-drop switch possesses high transmission efficiency (-1 dB), and the extinction ratio can be as high as 30 dB at 1.556 mu m. In addition, the transmission efficiency of drop port for the M-Z interferometric element can be -1.15 dB at 1.55 mu m. The designed elements are essential for the on-chip router in optical interconnect.
入藏号: WOS:000403820400004
ISSN: 1041-1135
eISSN: 1941-0174
第 105 条,共 255 条
标题: Self-weighted spectral clustering, with parameter-free constraint
作者: Zhang, R (Zhang, Rui); Nie, FP (Nie, Feiping); Li, XL (Li, Xuelong)
来源出版物: NEUROCOMPUTING 卷: 241 页: 164-170 DOI: 10.1016/j.neucom.2017.01.085 出版年: JUN 7 2017
摘要: The constrained spectral clustering (or known as the semi-supervised spectral clustering) focuses on enhancing the clustering capability by utilizing the side information. In this paper, a novel constrained spectral clustering method is proposed based on deriving a sparse parameter-free similarity. Different from other works, the proposed method transforms the given pairwise constraints into the intrinsic graph similarity and the penalty graph similarity respectively instead of incorporating them into one single similarity. Besides, the optimal weight can be automatically achieved to balance the graph optimization problems between the intrinsic graph and the penalty graph. Equipped with a general framework of efficiently unraveling the bi-objective optimization, the proposed method could obtain both ratio cut and normalized cut clusterings via updating the weighted Laplacian matrix until convergence. Moreover, the proposed method is equivalent to the spectral clustering, when no side information is provided. Consequently, the effectiveness and the superiority of the proposed method are further verified both analytically and empirically. (C) 2017 Elsevier B.V. All rights reserved.
入藏号: WOS:000398752700016
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhang, Rui         U-4639-2017         0000-0001-9418-0863
ISSN: 0925-2312
eISSN: 1872-8286
第 106 条,共 255 条
标题: Target reconstruction algorithm for four-beam sheared coherent imaging
作者: Lu, CM (Lu Chang-Ming); Chen, ML (Chen Ming-Lai); Luo, XJ (Luo Xiu-Juan); Zhang, Y (Zhang Yu); Liu, H (Liu Hui); Lan, FY (Lan Fu-Yang); Cao, B (Cao Bei)
来源出版物: ACTA PHYSICA SINICA 卷: 66 期: 11 文献号: 114201 DOI: 10.7498/aps.66.114201 出版年: JUN 5 2017
摘要: Sheared-beam imaging, which is a nonconventional coherent laser imaging technique, can be used to better solve the problem of taking pictures with high resolution for remote targets through turbulent medium than conventional optical methods. In the previous research on this technique, a target was illuminated by three coherent laser beams that were laterally arranged at the transmitter plane into an L pattern. In order to obtain a high quality image, a series of time-varying scattered signals is collected to reconstruct speckled images of the same object. To overcome atmospheric turbulence, multiple sets of three-beam laser should be emitted, which increases data acquisition time.
In this paper, aiming at the quasi real-time problem of conventional sheared beam imaging technique, we use four-beam laser with rectangular distribution instead of the traditional L type sheared three-beam laser to illuminate the target. According to this, we propose a target reconstruction algorithm for four-beam sheared coherent imaging to reconstruct four target images simultaneously in one measurement, which can acquire high quality images by reducing the amount of measurement and the speckle noise. Meanwhile, it can greatly reduce the amount of beam switching in multi-group emission and improve the imaging efficiency. Firstly, the principle of the four-beam sheared coherent imaging technique is deduced. Secondly, in the algorithm, the speckle amplitude and phase difference frames can be extracted accurately by searching for the accurate positions of the beat frequency components. Based on the speckle phase difference frames, four sets of wavefront phases can be demodulated by the least squares method, and wavefront amplitude can be obtained by algebraic operation of speckle amplitude. The reconstructed wavefront is used for inverse Fourier transform to yield a two-dimensional image. A series of speckled images is averaged to form an incoherent image. Finally, the validity of the proposed technique is verified by simulations. From the simulation results, the image quality of the proposed method is better than that of the traditional method in the same amount of measurement. Furthermore, on the premise of the same image quality, the data acquisition amount of the proposed method is 2-3 times as large as that of the traditional method. In other words, compared with that of the traditional method, the data acquisition time of the proposed method is reduced at least by half and the algorithm processing time is less. It can be concluded that the proposed imaging technique can not only improve the efficiency of target reconstruction, but also present a better way of imaging the remote moving targets.
入藏号: WOS:000403091100009
ISSN: 1000-3290
第 107 条,共 255 条
标题: Nonresonant background suppression in wide-field coherent anti-Stokes Raman scattering microscopy with transport of intensity equation based phase imaging
作者: Zheng, JJ (Zheng Juan-Juan); Yao, BL (Yao Bao-Li); Shao, XP (Shao Xiao-Peng)
来源出版物: ACTA PHYSICA SINICA 卷: 66 期: 11 文献号: 114206 DOI: 10.7498/aps.66.114206 出版年: JUN 5 2017
摘要: Coherent anti-Stokes Raman scattering (CARS) microscopy is a valuable tool for label-free imaging of biological samples, since it enables providing contrast via vibrational resonances of a specific chemical bond. However, in a conventional CARS image the Raman resonant anti-Stokes radiation is often superimposed by a nonresonant contribution arising from the electronic part of the polarization. The situation becomes worse if a sample is composed of a significant amount of water, where a strong nonresonant background over the whole image is obtained.
To date, various approaches including Epi, polarization sensitive, time-resolved, and CARS phase imaging have been implemented to suppress the undesirable nonresonant background in CARS microscopy. Notably, optical heterodyne based phase imaging schemes are of particular interest due to their intrinsic ability to retrieve Im(chi((3))), which is proportional to the Raman resonant signal. Nevertheless, all the reported phase imaging methods that require an independent reference wave lead to an increase in the setup complexity, thus making the measurement sensitive to external perturbations. In order to simplify the setup, single-beam scheme has also been utilized for vibrational CARS imaging by using wave-front sensors to acquire the phase of the complex anti-Stokes amplitude. However, this method demands highly accurate wave-front sensors.
In this paper we present a reference-less CARS phase imaging technique to suppress nonresonant CARS background based on transport of intensity equation (TIE). Resonant CARS radiation E-CARS(R) can be obtained when the frequency difference between the pump and Stokes beams is tuned to match a molecular vibration frequency (Raman resonant mode). In contrast, the nonresonant background E-CARS(NR) can be obtained when the frequency difference between the pump and Stokes beams does not match a molecular vibration frequency (Raman resonant mode). Considering the fact that there is a phase shift of pi/2 between the resonant and non-resonant CARS field, the phase imaging of both resonant and nonresonant CARS field can provide a background-free image. In implementation, three intensity images of the CARS field under resonant mode are recorded at three neighboring planes by moving the CCD camera along the axial direction. In the meantime, three images of the CARS field under non-resonant mode are also recorded. Considering the fact that the TIE links the intensity distributions in three neighboring planes (through which a beam transverses) with the phase distribution of the field, the phase images of the CARS field under both resonant and nonresonant modes are reconstructed from the recorded intensity images. The phase difference phi(x) between the resonant CARS field and the non-resonant CARS field is calculated. Eventually, the CARS background is efficiently suppressed by using the relation I-CARS(bf) proportional to I-CARS(R center dot) sin(2) phi(x).
Compared with conventional CARS background suppression techniques, the proposed method is robust against environmental disturbance, since it does not require an additional reference beam. Furthermore, the proposed method is easy to incorporate in a conventional CARS configuration. Therefore, the proposed method has the potential to become a versatile technique to image deep tissue with low background signal.
入藏号: WOS:000403091100014
ISSN: 1000-3290
第 108 条,共 255 条
标题: Coherent optical adaptive technique improves the spatial resolution of STED microscopy in thick samples
作者: Yan, W (Yan, Wei); Yang, YL (Yang, Yanlong); Tan, Y (Tan, Yu); Chen, X (Chen, Xun); Li, Y (Li, Yang); Qu, JL (Qu, Junle); Ye, T (Ye, Tong)
来源出版物: PHOTONICS RESEARCH 卷: 5 期: 3 页: 176-181 DOI: 10.1364/PRJ.5.000176 出版年: JUN 1 2017
摘要: Stimulated emission depletion (STED) microscopy is one of far-field optical microscopy techniques that can provide sub-diffraction spatial resolution. The spatial resolution of the STED microscopy is determined by the specially engineered beam profile of the depletion beam and its power. However, the beam profile of the depletion beam may be distorted due to aberrations of optical systems and inhomogeneity of a specimen's optical properties, resulting in a compromised spatial resolution. The situation gets deteriorated when thick samples are imaged. In the worst case, the severe distortion of the depletion beam profile may cause complete loss of the super-resolution effect no matter how much depletion power is applied to specimens. Previously several adaptive optics approaches have been explored to compensate aberrations of systems and specimens. However, it is difficult to correct the complicated high-order optical aberrations of specimens. In this report, we demonstrate that the complicated distorted wavefront from a thick phantom sample can be measured by using the coherent optical adaptive technique. The full correction can effectively maintain and improve spatial resolution in imaging thick samples. (C) 2017 Chinese Laser Press
入藏号: WOS:000405990300006
ISSN: 2327-9125
第 109 条,共 255 条
标题: Numerical simulation and temporal characterization of dual-pumped microring-resonator-based optical frequency combs
作者: Hu, XH (Hu, Xiaohong); Wang, WQ (Wang, Weiqiang); Wang, LR (Wang, Leiran); Zhang, WF (Zhang, Wenfu); Wang, YS (Wang, Yishan); Zhao, W (Zhao, Wei)
来源出版物: PHOTONICS RESEARCH 卷: 5 期: 3 页: 207-211 DOI: 10.1364/PRJ.5.000207 出版年: JUN 1 2017
摘要: Dual-pumped microring-resonator-based optical frequency combs (OFCs) and their temporal characteristics are numerically investigated and experimentally explored. The calculation results obtained by solving the driven and damped nonlinear Schrodinger equation indicate that an ultralow coupled pump power is required to excite the primary comb modes through a non-degenerate four-wave-mixing (FWM) process and, when the pump power is boosted, both the comb mode intensities and spectral bandwidths increase. At low pump powers, the field intensity profile exhibits a cosine variation manner with frequency equal to the separation of the two pumps, while a roll Turing pattern is formed resulting from the increased comb mode intensities and spectral bandwidths at high pump powers. Meanwhile, we found that the power difference between the two pump fields can be transferred to the newly generated comb modes, which are located on both sides of the pump modes, through a cascaded FWM process. Experimentally, the dual-pumped OFCs were realized by coupling two self-oscillating pump fields into a microring resonator. The numerically calculated comb spectrum is verified by generating an OFC with 2.0 THz mode spacing over 160 nm bandwidth. In addition, the formation of a roll Turing pattern at high pump powers is inferred from the measured autocorrelation trace of a 10 free spectral range (FSR) OFC. The experimental observations accord well with the numerical predictions. Due to their large and tunable mode spacing, robustness, and flexibility, the proposed dual-pumped OFCs could find potential applications in a wide range of fields, including arbitrary optical waveform generation, high-capacity optical communications, and signal-processing systems. (C) 2017 Chinese Laser Press
入藏号: WOS:000405990300011
ISSN: 2327-9125
第 110 条,共 255 条
标题: Three-dimensional characterization of tightly focused fields for various polarization incident beams
作者: Cai, YN (Cai, Yanan); Liang, YS (Liang, Yansheng); Lei, M (Lei, Ming); Yan, SH (Yan, Shaohui); Wang, ZJ (Wang, Zhaojun); Yu, XH (Yu, Xianghua); Li, MM (Li, Manman); Dan, D (Dan, Dan); Qian, J (Qian, Jia); Yao, BL (Yao, Baoli)
来源出版物: REVIEW OF SCIENTIFIC INSTRUMENTS 卷: 88 期: 6 文献号: 063106 DOI: 10.1063/1.4989519 出版年: JUN 2017
摘要: Tightly focused vectorial optical beams have found extensive applications in variety of technical fields like single-molecule detection, optical tweezers, and super-resolution optical microscopy. Such applications require an accurate measurement and manipulation of focal optical fields. We have developed a compact instrument (with dimensions of 35 x 35x 30 cm(3)) to rapidly measure the intensity distribution in three dimensions of the focused fields of vectorial beams and any other incident beams. This instrument employs a fluorescent nanoparticle as a probe to scan the focal region to obtain a high spatial resolution of intensity distribution. It integrates a liquid-crystal spatial light modulator to allow for tailoring the point spread function of the optical system, making it a useful tool for multi-purpose and flexible research. The robust applicability of the instrument is verified by measuring the 3D intensity distributions of focal fields of various polarization and wavefront modulated incident beams focused by a high NA (= 1.25) objective lens. The minimal data acquisition time achievable in the experiment is about 8 s for a scanning region of 3.2 x 3.2 x mu m(2) (512 x 512 pixels). The measured results are in good agreement with those predicted by the vectorial diffraction theory. Published by AIP Publishing.
入藏号: WOS:000404641300006
PubMed ID: 28667966
ISSN: 0034-6748
eISSN: 1089-7623
第 111 条,共 255 条
标题: A Method For Achieving Super Resolution Vibrational Sum-Frequency Generation Microscopy By Structured Illumination
作者: Li, YH (Li, Ya-Hui); Chen, DN (Chen, Dan-Ni); Niu, HB (Niu, Han-Ben)
来源出版物: IEEE PHOTONICS JOURNAL 卷: 9 期: 3 文献号: 3900708 DOI: 10.1109/JPHOT.2017.2705124 出版年: JUN 2017
摘要: A scheme was proposed to achieve wide-field vibrational sum-frequency generation (SFG) microscopy with subdiffraction-limited resolution in one dimension. In this approach, samples are illuminated with a structured visible field and a uniform IR field to induce vibrational sum-frequency generation. With five raw images acquired at five different phases of the visible stripe pattern, a super-resolved vibrational SFG (SR-SFG) image with the resolution triple to that of the original can be reconstructed. Theoretical framework describing the coherent image formation and reconstruction scheme for the SR-SFG imaging system was derived and carried out with numerical simulations to investigate its imaging performance. With a typical imaging system, the lateral resolution was improved from 390 nm of the conventional SFG imaging system, to around 130 nm of the SR-SFG imaging system.
入藏号: WOS:000404229700001
ISSN: 1943-0655
eISSN: 1943-0647
第 112 条,共 255 条
标题: Chiral long-period gratings: fabrication, highly sensitive torsion sensing, and tunable single-band filtering
作者: Kong, XD (Kong, Xudong); Ren, KL (Ren, Kaili); Ren, LY (Ren, Liyong); Liang, J (Liang, Jian); Ju, HJ (Ju, Haijuan)
来源出版物: APPLIED OPTICS 卷: 56 期: 16 页: 4702-4707 DOI: 10.1364/AO.56.004702 出版年: JUN 1 2017
摘要: A promising technology for fabricating chiral long-period gratings (CLPGs) is demonstrated using a commercial fusion splicer. The key aspect of this technology is the incorporation of a fully automatic program we designed for the fusion splicer. High-quality CLPGs are successfully fabricated from single-mode fibers, which have very flat surfaces and low insertion loss. We also investigate the tuning characteristics of the transmission spectrum with the mechanical twist rate in CLPGs for torsion sensing application. The torsion sensitivity is improved and the shift in resonance wavelength versus the mechanical twist rate shows an almost perfect linear relationship. In addition, by choosing appropriate fabrication parameters, the fabricated CLPGs can be used as tunable single-band-rejection filters in a broad wavelength range. (C) 2017 Optical Society of America
入藏号: WOS:000402579600020
PubMed ID: 29047605
ISSN: 1559-128X
eISSN: 2155-3165
第 113 条,共 255 条
标题: Robust Joint Graph Sparse Coding for Unsupervised Spectral Feature Selection
作者: Zhu, XF (Zhu, Xiaofeng); Li, XL (Li, Xuelong); Zhang, SC (Zhang, Shichao); Ju, CH (Ju, Chunhua); Wu, XD (Wu, Xindong)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 28 期: 6 页: 1263-1275 DOI: 10.1109/TNNLS.2016.2521602 出版年: JUN 2017
摘要: In this paper, we propose a new unsupervised spectral feature selection model by embedding a graph regularizer into the framework of joint sparse regression for preserving the local structures of data. To do this, we first extract the bases of training data by previous dictionary learning methods and, then, map original data into the basis space to generate their new representations, by proposing a novel joint graph sparse coding (JGSC) model. In JGSC, we first formulate its objective function by simultaneously taking subspace learning and joint sparse regression into account, then, design a new optimization solution to solve the resulting objective function, and further prove the convergence of the proposed solution. Furthermore, we extend JGSC to a robust JGSC (RJGSC) via replacing the least square loss function with a robust loss function, for achieving the same goals and also avoiding the impact of outliers. Finally, experimental results on real data sets showed that both JGSC and RJGSC outperformed the state-of-the-art algorithms in terms of k-nearest neighbor classification performance.
入藏号: WOS:000401982100002
PubMed ID: 26955053
ISSN: 2162-237X
eISSN: 2162-2388
第 114 条,共 255 条
标题: The Recognition of the Point Symbols in the Scanned Topographic Maps
作者: Miao, QG (Miao, Qiguang); Xu, PF (Xu, Pengfei); Li, XL (Li, Xuelong); Song, JF (Song, Jianfeng); Li, WS (Li, Weisheng); Yang, Y (Yang, Yun)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 26 期: 6 页: 2751-2766 DOI: 10.1109/TIP.2016.2613409 出版年: JUN 2017
摘要: It is difficult to separate the point symbols from the scanned topographic maps accurately, which brings challenges for the recognition of the point symbols. In this paper, based on the framework of generalized Hough transform (GHT), we propose a new algorithm, which is named shear line segment GHT (SLS-GHT), to recognize the point symbols directly in the scanned topographic maps. SLS-GHT combines the line segment GHT (LS-GHT) and the shear transformation. On the one hand, LS-GHT is proposed to represent the features of the point symbols more completely. Its R-table has double level indices, the first one is the color information of the point symbols, and the other is the slope of the line segment connected a pair of the skeleton points. On the other hand, the shear transformation is introduced to increase the directional features of the point symbols; it can make up for the directional limitation of LS-GHT indirectly. In this way, the point symbols are detected in a series of the sheared maps by LS-GHT, and the final optimal coordinates of the setpoints are gotten from a series of the recognition results. SLS-GHT detects the point symbols directly in the scanned topographic maps, totally different from the traditional pattern of extraction before recognition. Moreover, several experiments demonstrate that the proposed method allows improved recognition in complex scenes than the existing methods.
入藏号: WOS:000401296100014
ISSN: 1057-7149
eISSN: 1941-0042
第 115 条,共 255 条
标题: Re-Weighted Discriminatively Embedded K-Means for Multi-View Clustering
作者: Xu, JL (Xu, Jinglin); Han, JW (Han, Junwei); Nie, FP (Nie, Feiping); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 26 期: 6 页: 3016-3027 DOI: 10.1109/TIP.2017.2665976 出版年: JUN 2017
摘要: Recent years, more and more multi-view data are widely used in many real-world applications. This kind of data (such as image data) is high dimensional and obtained from different feature extractors, which represents distinct perspectives of the data. How to cluster such data efficiently is a challenge. In this paper, we propose a novel multi-view clustering framework, called re-weighted discriminatively embedded K-means, for this task. The proposed method is a multi-view least-absolute residual model, which induces robustness to efficiently mitigates the influence of outliers and realizes dimension reduction during multi-view clustering. Specifically, the proposed model is an unsupervised optimization scheme, which utilizes iterative re-weighted least squares to solve least-absolute residual and adaptively controls the distribution of multiple weights in a re-weighted manner only based on its own low-dimensional subspaces and a common clustering indicator matrix. Furthermore, theoretical analysis (including optimality and convergence analysis) and the optimization algorithm are also presented. Compared with several state-of-the-art multi-view clustering methods, the proposed method substantially improves the accuracy of the clustering results on widely used benchmark data sets, which demonstrates the superiority of the proposed work.
入藏号: WOS:000401296100033
ISSN: 1057-7149
eISSN: 1941-0042
第 116 条,共 255 条
标题: Multiple Auxiliaries Assisted Airborne Power Line Detection
作者: Shan, HT (Shan, Haotian); Zhang, J (Zhang, Jun); Cao, XB (Cao, Xianbin); Li, XL (Li, Xuelong); Wu, DP (Wu, Dapeng)
来源出版物: IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 卷: 64 期: 6 页: 4810-4819 DOI: 10.1109/TIE.2017.2668994 出版年: JUN 2017
摘要: Airborne power line detection is a key technique to ensure low altitude flight safety. Yet, it is a challenging problem due to the extremely small size of power line targets. Recently, auxiliary assisted detection has shown great potential in improving the power line detection performance. However, in existing methods, the auxiliaries and the contexts between the power lines and the auxiliaries are both manually assigned, thus limits its applicability. In this paper, a novelmultiple auxiliaries assisted power line detection method is proposed. With an optimization based auxiliaries selection and contexts acquisition scheme, the proposed method cannot only decide which auxiliaries should be selected to assist the detection, but also acquire the context information of each kind of auxiliaries, all in an automatic way. Experimental results show that the proposed method surpasses the state-of-the-art power line detection methods, both in terms of detection accuracy and false alarm probability.
入藏号: WOS:000401328500048
ISSN: 0278-0046
eISSN: 1557-9948
第 117 条,共 255 条
标题: Sparse Learning with Stochastic Composite Optimization
作者: Zhang, WZ (Zhang, Weizhong); Zhang, LJ (Zhang, Lijun); Jin, ZM (Jin, Zhongming); Jin, R (Jin, Rong); Cai, D (Cai, Deng); Li, XL (Li, Xuelong); Liang, RH (Liang, Ronghua); He, XF (He, Xiaofei)
来源出版物: IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 卷: 39 期: 6 页: 1223-1236 DOI: 10.1109/TPAMI.2016.2578323 出版年: JUN 2017
摘要: In this paper, we study Stochastic Composite Optimization (SCO) for sparse learning that aims to learn a sparse solution from a composite function. Most of the recent SCO algorithms have already reached the optimal expected convergence rate O(1/lambda T), but they often fail to deliver sparse solutions at the end either due to the limited sparsity regularization during stochastic optimization (SO) or due to the limitation in online-to-batch conversion. Even when the objective function is strongly convex, their high probability bounds can only attain O(root log(1/delta)/T with delta is the failure probability, which is much worse than the expected convergence rate. To address these limitations, we propose a simple yet effective two-phase Stochastic Composite Optimization scheme by adding a novel powerful sparse online-to-batch conversion to the general Stochastic Optimization algorithms. We further develop three concrete algorithms, OptimalSL, LastSL and AverageSL, directly under our scheme to prove the effectiveness of the proposed scheme. Both the theoretical analysis and the experiment results show that our methods can really outperform the existing methods at the ability of sparse learning and at the meantime we can improve the high probability bound to approximately O(log (log (T)/delta)/lambda T).
入藏号: WOS:000401091200013
PubMed ID: 27295652
ISSN: 0162-8828
eISSN: 1939-3539
第 118 条,共 255 条
标题: Ranging method based on linear frequency modulated laser
作者: Guo, N (Guo, Na); Gao, CX (Gao, Cunxiao); Xue, MY (Xue, Mingyuan); Niu, LQ (Niu, Linquan); Zhu, SL (Zhu, Shaolan); Feng, L (Feng, Li); He, HD (He, Haodong); Cao, ZY (Cao, Zongying)
来源出版物: LASER PHYSICS 卷: 27 期: 6 文献号: 065108 DOI: 10.1088/1555-6611/aa6da3 出版年: JUN 2017
摘要: In this paper, we obtain target information about the distance between laser sources and targets based on the linear frequency modulated laser ranging system. We designed a specific experimental scheme for the ranging of linear frequency modulated semiconductor lasers based on heterodyne ranging experiment. Ranging precision can reach micron dimension and range resolution is about 0.002 m within the range of 1-40 m. The ranging method in this paper can apply to laser radars which could be used to capture target information, which is very helpful for tracking, identifying and extracting targets.
入藏号: WOS:000401114300002
ISSN: 1054-660X
eISSN: 1555-6611
第 119 条,共 255 条
标题: 3D thermal analysis of end-pumped Nd3+-doped index-crossover gain guided-index antiguided fiber laser
作者: Zhang, WT (Zhang, Weitao); Shen, X (Shen, Xiao); Liu, JX (Liu, Jiaxi); Wei, W (Wei, Wei)
来源出版物: LASER PHYSICS 卷: 27 期: 6 文献号: 065101 DOI: 10.1088/1555-6611/aa6991 出版年: JUN 2017
摘要: Improved rate equations are established for the new model of index-crossover gain guided-index antiguided (IGG-IAG) fiber, then the pump and signal light power distribution along the IGG-IAG fiber are investigated. Based on the thermal conduction equations, the 3D temperature distributions of a one-end-pumped and dual-end-pumped Nd3+-doped IGG-IAG fiber laser are further analyzed. The simulation results show that many factors have an important influence on fiber temperature. The temperature of the fiber with the dual-end-pump method is obviously lower than that with the one-end-pump method, and the temperature distribution is more uniform. The larger the R value, the lower the fiber temperature, and the smaller the -Delta n, the lower the fiber temperature. Thus proper fiber parameters and pump scheme may help to reduce the fiber temperature.
入藏号: WOS:000399889000001
ISSN: 1054-660X
eISSN: 1555-6611
第 120 条,共 255 条
标题: A Novel PDE-Based Single Image Super-Resolution Reconstruction Method
作者: Zhao, XD (Zhao, Xiaodong); Cao, JZ (Cao, Jianzhong); Zhou, ZF (Zhou, Zuofeng); Huang, JJ (Huang, Jijiang)
来源出版物: INTERNATIONAL JOURNAL OF PATTERN RECOGNITION AND ARTIFICIAL INTELLIGENCE 卷: 31 期: 6 文献号: 1754010 DOI: 10.1142/S0218001417540106 出版年: JUN 2017
摘要: For applications such as remote sensing imaging and medical imaging, high-resolution (HR) images are urgently required. Image Super-Resolution (SR) reconstruction has great application prospects in optical imaging. In this paper, we propose a novel unified Partial Differential Equation (PDE)-based method to single image SR reconstruction. Firstly, two directional diffusion terms calculated by Anisotropic Nonlinear Structure Tensor (ANLST) are constructed, combing information of all channels to prevent singular results, making full use of its directional diffusion feature. Secondly, by introducing multiple orientations estimation using high order matrix-valued tensor instead of gradient, orientations can be estimated more precisely for junctions or corners. As a unique descriptor of orientations, mixed orientation parameter (MOP) is separated into two orientations by finding roots of a second-order polynomial in the nonlinear part. Then, we synthesize a Gradient Vector Flow (GVF) shock filter to balance edge enhancement and de-noising process. Experimental results confirm the validity of the method and show that the method enhances image edges, restores corners or junctions, and suppresses noise robustness, which is competitive with the existing methods.
入藏号: WOS:000399074600005
ISSN: 0218-0014
eISSN: 1793-6381
第 121 条,共 255 条
标题: Photon-limited depth and reflectivity imaging with sparsity regularization
作者: Kang, Y (Kang Yan); Li, LF (Li Lifei); Duan, XJ (Duan Xuejie); Zhang, TY (Zhang Tongyi); Li, DJ (Li Dongjian); Zhao, W (Zhao Wei)
来源出版物: OPTICS COMMUNICATIONS 卷: 392 页: 25-30 DOI: 10.1016/j.optcom.2017.01.032 出版年: JUN 1 2017
摘要: We demonstrate a depth and reflectivity imaging system at low light level based on sparsity regularization method. Depth and reflectivity imaging from the time-correlated single photon counting (TCSPC) measurement in limit of few photon counts are reconstructed through exploiting transform-domain sparsity. Two different sparsity-based penalty function: total variation (TV) penalty and l(1) norm penalty measuring sparsity in the discrete cosine transform(DCT) basis, are applied to the experimental data. The results show that compared with traditional image denoising method, sparsity regularization approach achieves better accuracy with fewer photon measurements. Further more, the performance of TV regularization is proved better than l(1)-DCT. regularization method for photon-limited imaging at first time, especially in the case of depth imaging. Our system is a photon-limited imaging device for a variety of applications, such as target detection, space surveillance, and distance measurement.
入藏号: WOS:000395604500005
ISSN: 0030-4018
eISSN: 1873-0310
第 122 条,共 255 条
标题: Dimensionality reduction method based on a tensor model
作者: Yan, RH (Yan, Ronghua); Peng, JY (Peng, Jinye); Ma, DM (Ma, Dongmei); Wen, DS (Wen, Desheng)
来源出版物: JOURNAL OF APPLIED REMOTE SENSING 卷: 11 文献号: 025011 DOI: 10.1117/1.JRS.11.025011 出版年: MAY 31 2017
摘要: Dimensionality reduction is a preprocessing step for hyperspectral image (HSI) classification. Principal component analysis reduces the spectral dimension and does not utilize the spatial information of an HSI. Both spatial and spectral information are used when an HSI is modeled as a tensor, that is, the noise in the spatial dimension is decreased and the dimension in a spectral dimension is reduced simultaneously. However, this model does not consider factors affecting the spectral signatures of ground objects. This means that further improving classification is very difficult. The authors propose that the spectral signatures of ground objects are the composite result of multiple factors, such as illumination, mixture, atmospheric scattering and radiation, and so on. In addition, these factors are very difficult to distinguish. Therefore, these factors are synthesized as within-class factors. Within-class factors, class factors, and pixels are selected to model a third-order tensor. Experimental results indicate that the classification accuracy of the new method is higher than that of the previous methods. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000402812000001
ISSN: 1931-3195
第 123 条,共 255 条
标题: Localized dark solitons and vortices in defocusing media with spatially inhomogeneous nonlinearity
作者: Zeng, JH (Zeng, Jianhua); Malomed, BA (Malomed, Boris A.)
来源出版物: PHYSICAL REVIEW E 卷: 95 期: 5 文献号: 052214 DOI: 10.1103/PhysRevE.95.052214 出版年: MAY 24 2017
摘要: Recent studies have demonstrated that defocusing cubic nonlinearity with local strength growing from the center to the periphery faster than r(D), in space of dimension D with radial coordinate r, supports a vast variety of robust bright solitons. In the framework of the same model, but with a weaker spatial-growth rate similar to r(alpha) with alpha <= D, we test here the possibility to create stable localized continuous waves (LCWs) in one-dimensional (1D) and 2D geometries, localized dark solitons (LDSs) in one dimension, and localized dark vortices (LDVs) in two dimensions, which are all realized as loosely confined states with a divergent norm. Asymptotic tails of the solutions, which determine the divergence of the norm, are constructed in a universal analytical form by means of the Thomas-Fermi approximation (TFA). Global approximations for the LCWs, LDSs, and LDVs are constructed on the basis of interpolations between analytical approximations available far from (TFA) and close to the center. In particular, the interpolations for the 1D LDS, as well as for the 2D LDVs, are based on a deformed-tanh expression, which is suggested by the usual 1D dark-soliton solution. The analytical interpolations produce very accurate results, in comparison with numerical findings, for the 1D and 2D LCWs, 1D LDSs, and 2D LDVs with vorticity S = 1. In addition to the 1D fundamental LDSs with the single notch and 2D vortices with S = 1, higher-order LDSs with multiple notches are found too, as well as double LDVs, with S = 2. Stability regions for the modes under consideration are identified by means of systematic simulations, the LCWs being completely stable in one and two dimensions, as they are ground states in the corresponding settings. Basic evolution scenarios are identified for those vortices that are unstable. The settings considered in this work may be implemented in nonlinear optics and in Bose-Einstein condensates.
入藏号: WOS:000402019500003
PubMed ID: 28618638
作者识别号:
作者        ResearcherID 号        ORCID 号
Malomed, Boris         F-6812-2017         
ISSN: 2470-0045
eISSN: 2470-0053
第 124 条,共 255 条
标题: Traveling wave deflector design for femtosecond streak camera
作者: Pei, CQ (Pei, Chengquan); Wu, SL (Wu, Shengli); Luo, D (Luo, Duan); Wen, WL (Wen, Wenlong); Xu, JK (Xu, Junkai); Tian, JS (Tian, Jinshou); Zhang, MR (Zhang, Minrui); Chen, P (Chen, Pin); Chen, JZ (Chen, Jianzhong); Liu, R (Liu, Rong)
来源出版物: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 卷: 855 页: 148-153 DOI: 10.1016/j.nima.2017.02.062 出版年: MAY 21 2017
摘要: In this paper, a traveling wave deflection deflector (TWD) with a slow-wave property induced by a microstrip transmission line is proposed for femtosecond streak cameras. The pass width and dispersion properties were simulated. In addition, the dynamic temporal resolution of the femtosecond camera was simulated by CST software. The results showed that with the proposed TWD a femtosecond streak camera can achieve a dynamic temporal resolution of less than 600 fs. Experiments were done to test the femtosecond streak camera, and an 800 fs dynamic temporal resolution was obtained. Guidance is provided for optimizing a femtosecond streak camera to obtain higher temporal resolution.
入藏号: WOS:000399846900019
ISSN: 0168-9002
eISSN: 1872-9576
第 125 条,共 255 条
标题: Efficiency analysis of 808 nm laser diode array under different operating temperatures
作者: Song, YF (Song Yun-Fei); Wang, ZF (Wang Zhen-Fu); Li, T (Li Te); Yang, GW (Yang Guo-Wen)
来源出版物: ACTA PHYSICA SINICA 卷: 66 期: 10 文献号: 104202 DOI: 10.7498/aps.66.104202 出版年: MAY 20 2017
摘要: The 808 nm high-efficiency laser diodes have many advantages, such as high output power, high reliabilities, compact sizes, which are widely used in many areas, such as industry, communication, science, medicine and biology. In order to improve the power conversion efficiencies of 808 nm laser diodes, the following requirements must be considered, such as loss of joule heating, loss by the carrier leakage, spontaneous radiation loss below the threshold current, loss by interface voltage defect, internal losses including free-carrier absorption loss and scattering loss. These losses above are closely related to the operating temperature of laser diode. In this paper, power conversion efficiency analysis is demonstrated from the aspects of the output power, threshold current, slope efficiency, voltage, and series resistance at different temperatures.. This is the first time that the detailed study has been carried out under various temperatures (up to the lowest temperature of -40 degrees C). And the detailed study above can be of benefit to designing the wafer epitaxial structure.
High-power 808 nm laser diode arrays are mounted on conduction cooled heatsinks. And the laser chips have 47 emitters with 50% in fill factor, 100 mu m stripe in width and 1.5 mm in cavity length. The asymmetric broad waveguide epitaxial structure with lower absorption loss in p-type waveguide and cladding layer is designed in order to reduce the internal losses. The device performances are measured under operating temperatures ranging from -40 degrees C to 25 degrees C including the output power, threshold current, slope efficiency, series resistance, voltage, etc. Then the power conversion efficiency of 808 nm laser diode arrays are demonstrated from the output characteristics at different operating temperatures.
With temperature decreasing, the series resistance gradually increases. The loss of joule heating ratio rises from 7.8% to 10.3%. In that case, the high series resistance is the major factor to prevent the efficiency from further improving at a low temperature of -40 degrees C. As temperature decreases from 25 degrees C to -40 degrees C, the carrier leakage ratio is reduced from 16.6% to 3.1%, the carrier leakage is the dominant factor for increasing efficiency, which means that it is necessary to optimize the epitaxial structure in order to reduce the carrier leakage at the room temperature. Comparing the two different work temperatures from -30 degrees C to -40 degrees C, the carrier leakage ratio only changes 0.1%, which implies that the carrier leakage could be ignored under the low temperature. Meanwhile, as temperature decreases from 25 degrees C to -40 degrees C, the power conversion efficiency increases from 56.7% to 66.8%.
入藏号: WOS:000403088000013
ISSN: 1000-3290
第 126 条,共 255 条
标题: Ultrasensitive terahertz metamaterial sensor based on spoof surface plasmon
作者: Chen, X (Chen, Xu); Fan, WH (Fan, Wenhui)
来源出版物: SCIENTIFIC REPORTS 卷: 7 文献号: 2092 DOI: 10.1038/s41598-017-01781-6 出版年: MAY 18 2017
摘要: A planar terahertz metamaterial sensor consisting of a corrugated metal stripe perforated by three rectangular grooves is proposed and investigated numerically. Due to the formation of Fabry-Perot resonance of the spoof surface plasmons mode on the corrugated metal stripe, the extremely sharp resonance in transmission spectrum associated with strong local field enhancement and high quality factor can be realized and exploited for ultrasensitive sensing. Since the intense interaction between electromagnetic waves and analyte materials, the frequency sensitivity of 1.966 THz per refractive index unit and the figure of merit of 19.86 can be achieved. Meanwhile, the film thickness sensitivity of this metamaterial sensor is higher than 52.5 GHz/mu m when the analyte thickness is thinner than 4 mu m. More interestingly, we find that the metal thickness has a great effect on the sensor performance. These findings open up opportunities for planar metamaterial structures to be developed into practical sensors in terahertz regime.
入藏号: WOS:000401526200031
PubMed ID: 28522859
ISSN: 2045-2322
第 127 条,共 255 条
标题: Effect of iodine (I-2) on structural, thermal and optical properties of Ge-Sb-S chalcohalide host glasses and ones doped with Dy
作者: Guo, Q (Guo, Quan); Xu, YT (Xu, Yantao); Guo, HT (Guo, Haitao); Xiao, XS (Xiao, Xusheng); Lin, CG (Lin, Changgui); Cui, XX (Cui, Xiaoxia); Wang, PF (Wang, Pengfei); Gao, F (Gao, Fei); Lu, M (Lu, Min); Peng, B (Peng, Bo)
来源出版物: JOURNAL OF NON-CRYSTALLINE SOLIDS 卷: 464 页: 81-88 DOI: 10.1016/j.jnoncrysol.2017.03.024 出版年: MAY 15 2017
摘要: A serial (100 - x)Ge25Sb10S65-xI (x = 0, 5, 10, 15, 20, 25 and 30 wt%) chalcohalide glasses and ones doped with 0.1 wt% Dy3+ rare-earth ions were synthesized and their structural, thermal and optical properties were systematically studied. It indicates that addition of I-2 into Ge25Sb10S65 glass significantly decreases the connectivity of glass network and average bond energy, and modifies the associated properties. The glass transition temperature and refractive index decrease monotonically, and the density increases almost linearly with the increasing of iodine content in glass. The thermal stability is improved, which has a maximum of Delta T-max = 174 degrees C. While the optical bandgap has a peak value at x = 10 wt. The absorption spectra and mid-infrared fluorescence spectra of Dy3+ rare-earth ions doped glasses were investigated together with the Judd-Ofelt analysis. GeS2 nano-crystals were found in the sample with x >= 15 wt, which is supposed to induce enhancements of mid-infrared fluorescence at 2.95 and 432 mu m. (C) 2017 Elsevier B.V. All rights reserved.
入藏号: WOS:000404205100012
作者识别号:
作者        ResearcherID 号        ORCID 号
Lin, Changgui         B-8915-2009         0000-0002-0574-6296
ISSN: 0022-3093
eISSN: 1873-4812
第 128 条,共 255 条
标题: Study of the interaction between graphene and planar terahertz metamaterial with toroidal dipolar resonance
作者: Chen, X (Chen, Xu); Fan, WH (Fan, Wenhui)
来源出版物: OPTICS LETTERS 卷: 42 期: 10 页: 2034-2037 DOI: 10.1364/OL.42.002034 出版年: MAY 15 2017
摘要: A planar terahertz metamaterial consisting of square split ring resonators is proposed, and the excitation of toroidal dipolar resonance is demonstrated. Moreover, we theoretically investigate the strong interaction between graphene and toroidal dipolar resonance of the metamaterial. By varying its Fermi energy, the simulations show that graphene can actively modulate the transmission amplitude of toroidal dipolar resonance and even switch it off. The interaction of the toroidal dipolar resonance with monolayer graphene further highlights the ultrasensitive sensing characteristic of the planar metamaterial, which can be utilized for other graphene-like two-dimensional materials. These intriguing properties of the proposed metamaterial may have potential applications in terahertz modulators and ultrasensitive sensors. (C) 2017 Optical Society of America
入藏号: WOS:000401424900042
PubMed ID: 28504742
ISSN: 0146-9592
eISSN: 1539-4794
第 129 条,共 255 条
标题: Terahertz spectroscopy and solid-state density functional theory calculations of structural isomers: Nicotinic acid, isonicotinic acid and 2-picolinic acid
作者: Ding, L (Ding, Ling); Fan, WH (Fan, Wen-Hui); Chen, X (Chen, Xu); Chen, ZY (Chen, Ze-You); Song, C (Song, Chao)
来源出版物: MODERN PHYSICS LETTERS B 卷: 31 期: 13 文献号: 1750149 DOI: 10.1142/S0217984917501494 出版年: MAY 10 2017
摘要: We report, for the first time to our knowledge, the terahertz (THz) spectra of isonicotinic acid and 2-picolinic acid. The distinct THz spectral differences among these two isomers and nicotinic acid have also been observed, indicating that the THz vibrational modes are highly sensitive to the structural differences even in similar molecular crystals. Besides, solid-state density functional theory calculations reveal better qualitative agreement with the measured absorption features, which are related to the molecular vibrations of nicotinic acid and isonicotinic acid. As for 2-picolinic acid, the calculation based on the primitive cell reproduces the absorption features at 1.46, 1.82 and 2.46 THz originating from intermolecular vibrations. These results suggest that THz spectra can identify the complex intermolecular interactions even in similar molecular crystals, which shows potential applications in identifying isomers in food and pharmaceutical production.
入藏号: WOS:000401631500007
ISSN: 0217-9849
eISSN: 1793-6640
第 130 条,共 255 条
标题: Numerical investigation of a microfiber-plane-grating composite optical waveguide for gas refractive index sensing
作者: Ma, CJ (Ma, Chengju); Ren, LY (Ren, Liyong); Guo, WE (Guo, Wenge); Fu, HW (Fu, Haiwei); Xu, YP (Xu, Yiping); Liu, YG (Liu, Yinggang); Wen, J (Wen, Jin)
来源出版物: APPLIED OPTICS 卷: 56 期: 14 页: 3984-3988 DOI: 10.1364/AO.56.003984 出版年: MAY 10 2017
摘要: In this paper, we propose a microfiber-plane-grating composite optical waveguide (MPGCOW), which is formed by immobilizing a tapered microfiber on the surface of a plane grating with one defect, for gas refractive index ( RI) sensing. Its optical properties and gas RI sensing properties are investigated by the finite difference time domain method. Results show that the MPGCOW has a photonic stop band and is very sensitive to the ambient gas RI variation. The largest gas RI sensing sensitivity of 486.67 nm/RIU and detection limit of 2 x 10(-6) are obtained by immersing the structure in the mixture gas of N-2 and He with various mixture ratios. (C) 2017 Optical Society of America
入藏号: WOS:000401020800004
PubMed ID: 29047525
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 131 条,共 255 条
标题: Numerical analysis of wide-field optical imaging with a sub-20 nm resolution based on a meta-sandwich structure
作者: Cao, S (Cao, Shun); Wang, TS (Wang, Taisheng); Yang, JZ (Yang, Jingzhong); Hu, BL (Hu, Bingliang); Levy, U (Levy, Uriel); Yu, WX (Yu, Weixing)
来源出版物: SCIENTIFIC REPORTS 卷: 7 文献号: 1328 DOI: 10.1038/s41598-017-01521-w 出版年: MAY 2 2017
摘要: Biological research requires wide-field optical imaging techniques with resolution down to the nanometer scale to study the biological process in a sub-cell or single molecular level. To meet this requirement, wide-field structured illumination method (WFSIM) has been extensively studied. The resolution of WFSIM is determined by the period of the optical interference pattern. However, in traditional WFSIM this period is diffraction limited so that pattern having periodicity smaller than 100 nm cannot be generated and as a result achieving an imaging resolution better than 50 nm is a great challenge. Here, we demonstrate a wide-field optical nanoimaging method based on a meta-sandwich structure (MSS) model. It is found that this structure can support standing wave surface plasmons interference pattern with a period of only 31 nm for 532 nm wavelength incident light. Furthermore, the potential application of the MSS for wide-field super-resolution imaging is discussed and the simulation results show an imaging resolution of sub-20 nm can be achieved. The demonstrated method paves a new route for the improvement of the wide field optical nanoimaging, which can be applied by biological researchers to study biological process conducted in cell membrane, such as mass transportation and others.
入藏号: WOS:000400449700003
PubMed ID: 28465520
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 132 条,共 255 条
标题: Observation of spin and orbital rotation of red blood cell in dual-beam fibre-optic trap with transverse offset
作者: Chen, XL (Chen, Xinlin); Xiao, GZ (Xiao, Guangzong); Han, X (Han, Xiang); Xiong, W (Xiong, Wei); Luo, H (Luo, Hui); Yao, BL (Yao, Baoli)
来源出版物: JOURNAL OF OPTICS 卷: 19 期: 5 文献号: 055612 DOI: 10.1088/2040-8986/aa66c1 出版年: MAY 2017
摘要: The spin and orbital rotation of the red blood cell (RBC) are achieved simultaneously by introducing a transverse offset to the dual-beam fibre-optic trap. The motion type of the captured RBC could be controlled by adjusting the offset distance. When the offset distance is relatively small, the RBC is observed to spin in the trap centre, with the spin frequency increasing linearly with the offset distance. Once the offset distance is above a critical value, the RBC will rotate along an elliptic orbit, together with the spin motion. The orbital rotation frequency and spin frequency both decrease with the increased offset distance. This technique allows mixing and viewing living cells from different perspectives concurrently without exposing them to any mechanical contact, and is generally applicable to biological and medical research.
入藏号: WOS:000413267500001
ISSN: 2040-8978
eISSN: 2040-8986
第 133 条,共 255 条
标题: How to obtain a shortest mode converter based on periodic waveguide with limited index contrast?
作者: Zhang, LX (Zhang, Lingxuan); Zhang, WF (Zhang, Wenfu); Wang, GX (Wang, Guoxi); Hu, YW (Hu, Yaowei); Ge, ZQ (Ge, Zhiqiang); Wang, LR (Wang, Leiran); Sun, QB (Sun, Qibing); Wang, WQ (Wang, Weiqiang); Gong, YK (Gong, Yongkang); Zhao, W (Zhao, Wei)
来源出版物: APPLIED PHYSICS B-LASERS AND OPTICS 卷: 123 期: 5 文献号: 140 DOI: 10.1007/s00340-017-6718-7 出版年: MAY 2017
摘要: Mode converter is one of most significant elements in photonic integrated circuits. It relies on increasing index contrast to shorten its length. However, index contrast is limited for technology. In addition, an overlarge index contrast leads to some disadvantages, such as large scattering loss, reflection loss, and small tolerance for manufacturing. Thus, an approximate scheme to design a mode converter is manipulating the transverse distribution of index to achieve the minimum length when the index contrast is given. We have analytically deduced the theoretical maximum coupled efficiency in periodic waveguide, which determines the minimum coupling length of mode converter. What is more, we have demonstrated how to construct a distribution function of indices in a cross section of waveguide to achieve the minimum length and a case is also given to illustrate the process. Proofs, based on both mathematic derivation and numerical simulation, have been exhibited in the paper.
入藏号: WOS:000402982600002
ISSN: 0946-2171
eISSN: 1432-0649
第 134 条,共 255 条
标题: Coarse-to-Fine Learning for Single-Image Super-Resolution
作者: Zhang, KB (Zhang, Kaibing); Tao, DC (Tao, Dacheng); Gao, XB (Gao, Xinbo); Li, XL (Li, Xuelong); Li, J (Li, Jie)
来源出版物: IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 卷: 28 期: 5 页: 1109-1122 DOI: 10.1109/TNNLS.2015.2511069 出版年: MAY 2017
摘要: This paper develops a coarse-to-fine framework for single-image super-resolution (SR) reconstruction. The coarse-to-fine approach achieves high-quality SR recovery based on the complementary properties of both example learning- and reconstruction-based algorithms: example learning-based SR approaches are useful for generating plausible details from external exemplars but poor at suppressing aliasing artifacts, while reconstruction-based SR methods are propitious for preserving sharp edges yet fail to generate fine details. In the coarse stage of the method, we use a set of simple yet effective mapping functions, learned via correlative neighbor regression of grouped low-resolution (LR) to high-resolution (HR) dictionary atoms, to synthesize an initial SR estimate with particularly low computational cost. In the fine stage, we devise an effective regularization term that seamlessly integrates the properties of local structural regularity, nonlocal self-similarity, and collaborative representation over relevant atoms in a learned HR dictionary, to further improve the visual quality of the initial SR estimation obtained in the coarse stage. The experimental results indicate that our method outperforms other state-of-the-art methods for producing high-quality images despite that both the initial SR estimation and the followed enhancement are cheap to implement.
入藏号: WOS:000401981800008
ISSN: 2162-237X
eISSN: 2162-2388
第 135 条,共 255 条
标题: Collective Representation for Abnormal Event Detection
作者: Ye, RZ (Ye, Renzhen); Li, XL (Li, Xuelong)
来源出版物: JOURNAL OF COMPUTER SCIENCE AND TECHNOLOGY 卷: 32 期: 3 页: 470-479 DOI: 10.1007/s11390-017-1737-8 出版年: MAY 2017
摘要: Abnormal event detection in crowded scenes is a hot topic in computer vision and information retrieval community. In this paper, we study the problems of detecting anomalous behaviors within the video, and propose a robust collective representation with multi-feature descriptors for abnormal event detection. The proposed method represents different features in an identical representation, in which different features of the same topic will show more common properties. Then, we build the intrinsic relation between different feature descriptors and capture concept drift in the video sequence, which can robustly discriminate between abnormal events and normal events. Experimental results on two benchmark datasets and the comparison with the state-of-the-art methods validate the effectiveness of our method.
入藏号: WOS:000401069100006
会议名称: 5th International Conference on Computational Visual Media (CVM)
会议日期: APR 12-14, 2017
会议地点: Nankai Univ, Tianjin, PEOPLES R CHINA
会议主办方: Nankai Univ
ISSN: 1000-9000
eISSN: 1860-4749
第 136 条,共 255 条
标题: Design, fabrication, and optical gain performance of the gain-guided and index-antiguided Nd3+-doped phosphate glass fiber
作者: Shen, X (Shen, Xiao); Zhang, LL (Zhang, Liaolin); Ding, JY (Ding, Jianyong); Wei, W (Wei, Wei)
来源出版物: JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS 卷: 34 期: 5 页: 998-1003 DOI: 10.1364/JOSAB.34.000998 出版年: MAY 1 2017
摘要: Design, fabrication, and optical gain performance of the gain-guided and index-antiguided (GG-IAG) fiber are studied systematically in this work. The main parameters of the GG-IAG fiber, i.e., a,triangle n, g, and eta, are designed by single-mode operation theories, followed by a detailed study of the fabrication of the GG-IAG fiber, including preform design and fabrication, fiber-drawing conditions, and so on. GG-IAG fibers with different core diameters (100-380 mu m) are obtained and their corresponding performance is measured. In order to verify whether the parameters of the fabricated GG-IAG fiber meet the theoretical design, the laser amplifier experiments of the GG-IAG fiber and the fabricated gain-guided and index-guided (GG-IG) fiber are both demonstrated. The experimental results show that the net optical gain coefficient of the GG-IG fiber is the sum of the net optical gain coefficient and the leakage loss coefficient of the GG-IAG fiber, which indicates that the fabricated GG-IAG fiber parameters and performance are consistent with the theoretical design. This work should help further exploration of the GG-IAG fiber. (C) 2017 Optical Society of America
入藏号: WOS:000400495900025
ISSN: 0740-3224
eISSN: 1520-8540
第 137 条,共 255 条
标题: Transverse spinning of particles in highly focused vector vortex beams
作者: Li, MM (Li, Manman); Yan, SH (Yan, Shaohui); Liang, YS (Liang, Yansheng); Zhang, P (Zhang, Peng); Yao, BL (Yao, Baoli)
来源出版物: PHYSICAL REVIEW A 卷: 95 期: 5 文献号: 053802 DOI: 10.1103/PhysRevA.95.053802 出版年: MAY 1 2017
摘要: Transverse spin angular momentum, which appears locally in the structured optical fields, has attracted much attention, owing to its extraordinary properties and potential applications. We show theoretically that, by highly focusing a vector vortex beam with azimuthally varied polarization, it is possible to trap multiple particles simultaneously and manipulate the particles' spin along the azimuthal direction. Both the direction and the magnitude of the spin angular momentum, so the spin torque on the particle, can be varied by changing the state of the input beams. Moreover, the magnitude of the spin torque can be manipulated further by changing the characteristics of the particles. Such results may be exploited in practical optical manipulation, especially for optically induced rotations.
入藏号: WOS:000400650300006
ISSN: 2469-9926
eISSN: 2469-9934
第 138 条,共 255 条
标题: Hyperspectral Image Superresolution by Transfer Learning
作者: Yuan, Y (Yuan, Yuan); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang)
来源出版物: IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING 卷: 10 期: 5 页: 1963-1974 DOI: 10.1109/JSTARS.2017.2655112 子辑: 1 出版年: MAY 2017
摘要: Hyperspectral image superresolution is a highly attractive topic in computer vision and has attracted many researchers' attention. However, nearly all the existing methods assume that multiple observations of the same scene are required with the observed low-resolution hyperspectral image. This limits the application of superresolution. In this paper, we propose a new framework to enhance the resolution of hyperspectral images by exploiting the knowledge from natural images: The relationship between low/high-resolution images is the same as that between low/high-resolution hyperspectral images. In the proposed framework, the mapping between low-and high-resolution images can be learned by deep convolutional neural network and be transferred to hyperspectral image by borrowing the idea of transfer learning. In addition, to study the spectral characteristic between low-and high-resolution hyperspectral image, collaborative nonnegative matrix factorization (CNMF) is proposed to enforce collaborations between the low-and high-resolution hyperspectral images, which encourages the estimated solution to extract the same endmembers with low-resolution hyperspectral image. The experimental results on ground based and remote sensing data suggest that the proposed method achieves comparable performance without requiring any auxiliary images of the same scene.
入藏号: WOS:000399682500024
ISSN: 1939-1404
eISSN: 2151-1535
第 139 条,共 255 条
标题: Photonic Microwave and mm-Wave Mixer for Multichannel Fiber Transmission
作者: Gao, YS (Gao, Yongsheng); Wen, AJ (Wen, Aijun); Zhang, W (Zhang, Wu); Wang, Y (Wang, Yong); Zhang, HX (Zhang, Huixing)
来源出版物: JOURNAL OF LIGHTWAVE TECHNOLOGY 卷: 35 期: 9 页: 1566-1574 DOI: 10.1109/JLT.2017.2652122 出版年: MAY 1 2017
摘要: Photonic microwave and millimeter wave (mm-wave) frequency conversion is a promising technique for future electronic systems due to its large bandwidth, electromagnetic immunity, and compatibility with other optical systems. However, the conversion gain of a photonic mixer is often low and may be further reduced by the fiber dispersion. In this paper, a photonic microwave and mm-wave mixer using an integrated polarization division multiplexing Mach-Zehnder modulator (PDM-MZM) is proposed, which exhibits the merits of high conversion gain, high purity, and compensation of the power fading in multichannel fiber transmission. By suppressing the optical carrier and optimizing the modulation index, the conversion gain and isolation are respectively improved by 27.6 and 55.3 dB in the experiment. After power compensation, high and relatively flat microwave and mm-wave signals from 12 to 45 GHz are obtained after transmission over 25-km fiber. In addition, an up-converted 38-GHz mm-wave signal carrying 100-MSym/s 16-quadrature amplitude modulation (16QAM) vector signal is simultaneously transmitted over four channels with different fiber length (back to back, 4, 25, and 50 km). The power fading in each channel can be independently compensated, and good electrical spectra, constellation diagrams, and receiver sensitivity are obtained.
入藏号: WOS:000399985600012
作者识别号:
作者        ResearcherID 号        ORCID 号
Gao, Yongsheng         I-5174-2017         0000-0002-0388-0096
ISSN: 0733-8724
eISSN: 1558-2213
第 140 条,共 255 条
标题: Heterogeneous Face Recognition: A Common Encoding Feature Discriminant Approach
作者: Gong, DH (Gong, Dihong); Li, ZF (Li, Zhifeng); Huang, WL (Huang, Weilin); Li, XL (Li, Xuelong); Tao, DC (Tao, Dacheng)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 26 期: 5 页: 2079-2089 DOI: 10.1109/TIP.2017.2651380 出版年: MAY 2017
摘要: Heterogeneous face recognition is an important, yet challenging problem in face recognition community. It refers to matching a probe face image to a gallery of face images taken from alternate imaging modality. The major challenge of heterogeneous face recognition lies in the great discrepancies between different image modalities. Conventional face feature descriptors, e.g., local binary patterns, histogram of oriented gradients, and scale-invariant feature transform, are mostly designed in a handcrafted way and thus generally fail to extract the common discriminant information from the heterogeneous face images. In this paper, we propose a new feature descriptor called common encoding model for heterogeneous face recognition, which is able to capture common discriminant information, such that the large modality gap can be significantly reduced at the feature extraction stage. Specifically, we turn a face image into an encoded one with the encoding model learned from the training data, where the difference of the encoded heterogeneous face images of the same person can be minimized. Based on the encoded face images, we further develop a discriminant matching method to infer the hidden identity information of the cross-modality face images for enhanced recognition performance. The effectiveness of the proposed approach is demonstrated (on several public-domain face datasets) in two typical heterogeneous face recognition scenarios: matching NIR faces to VIS faces and matching sketches to photographs.
入藏号: WOS:000399396400001
PubMed ID: 28092545
ISSN: 1057-7149
eISSN: 1941-0042
第 141 条,共 255 条
标题: Learning Discriminative Binary Codes for Large-scale Cross-modal Retrieval
作者: Xu, X (Xu, Xing); Shen, FM (Shen, Fumin); Yang, Y (Yang, Yang); Shen, HT (Shen, Heng Tao); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 26 期: 5 页: 2494-2507 DOI: 10.1109/TIP.2017.2676345 出版年: MAY 2017
摘要: Hashing based methods have attracted considerable attention for efficient cross-modal retrieval on large-scale multimedia data. The core problem of cross-modal hashing is how to learn compact binary codes that construct the underlying correlations between heterogeneous features from different modalities. A majority of recent approaches aim at learning hash functions to preserve the pairwise similarities defined by given class labels. However, these methods fail to explicitly explore the discriminative property of class labels during hash function learning. In addition, they usually discard the discrete constraints imposed on the to-be-learned binary codes, and compromise to solve a relaxed problem with quantization to obtain the approximate binary solution. Therefore, the binary codes generated by these methods are suboptimal and less discriminative to different classes. To overcome these drawbacks, we propose a novel cross-modal hashing method, termed discrete cross-modal hashing (DCH), which directly learns discriminative binary codes while retaining the discrete constraints. Specifically, DCH learns modality-specific hash functions for generating unified binary codes, and these binary codes are viewed as representative features for discriminative classification with class labels. An effective discrete optimization algorithm is developed for DCH to jointly learn the modality-specific hash function and the unified binary codes. Extensive experiments on three benchmark data sets highlight the superiority of DCH under various cross-modal scenarios and show its state-of-the-art performance.
入藏号: WOS:000399396400031
PubMed ID: 28278464
ISSN: 1057-7149
eISSN: 1941-0042
第 142 条,共 255 条
标题: Er-doped mode-locked fiber laser with WS2/fluorine mica (FM) saturable absorber
作者: Li, L (Li, Lu); Wang, YG (Wang, Yonggang); Wang, X (Wang, Xi); Yang, GW (Yang, Guowen); Jiang, SZ (Jiang, Shouzhen); Li, Z (Li, Zhen); Man, BY (Man, Baoyuan); Wang, YS (Wang, Yishan)
来源出版物: OPTICS AND LASER TECHNOLOGY 卷: 90 页: 109-112 DOI: 10.1016/j.optlastec.2016.10.011 出版年: MAY 1 2017
摘要: The report presents conventional soliton 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 composite, FM has higher softening temperature, heat dissipation and laser damage threshold. In this work, the modulation depth (MD) and non-saturable loss (NL) of WS2/FM SA are measured to be 3.1% and 15%, respectively. By employing the SA, a stable conventional soliton mode-locked fiber laser is achieved. The repetition rate is 8.2 MHz and the pulse duration is 830 fs. The fiber laser works in mode locking operation for at least ten days and no damage of the SA is observed. The results indicate that WS2/FM material is an ideal SA for Er-doped fiber (EDF) lasers.
入藏号: WOS:000392778600016
ISSN: 0030-3992
eISSN: 1879-2545
第 143 条,共 255 条
标题: Nonlinear optical response and applications of tin disulfide in the near- and mid-infrared
作者: Yang, HR (Yang, H. R.); Liu, XM (Liu, X. M.)
来源出版物: APPLIED PHYSICS LETTERS 卷: 110 期: 17 文献号: 171106 DOI: 10.1063/1.4982624 出版年: APR 24 2017
摘要: Layered metal dichalcogenides (LMDs) have received considerable attention in optoelectronics and photonics. Tin disulfide (SnS2) as a member of the LMDs has been employed for transistors, energy storage, and photocatalysts. The optical properties of SnS2 in the ultraviolet and visible regions have been widely investigated, while the applications of SnS2 in the near-and mid-infrared regions are still rare. Here, we demonstrate the nonlinear optical response of layered SnS2 that is exploited as a saturable absorber in the near-and mid-infrared regions. The saturable absorption of SnS2 is measured at 1.06 and 1.55 mu m, which illustrates a low saturable intensity. SnS2 covered on a D-shaped fiber is used to initiate the mode-locking operations in erbium-, ytterbium-, and thulium-doped fiber lasers and ultrafast pulses are achieved at 1.03, 1.56, and 1.91 mu m. These results make SnS2 an appealing candidate for broadband applications across the near-and mid-infrared regions. Published by AIP Publishing.
入藏号: WOS:000400380200006
ISSN: 0003-6951
eISSN: 1077-3118
第 144 条,共 255 条
标题: Analysis of the influence of diattenuation on optical imaging system by using the theory of vector plane wave spectrum
作者: Zhang, MR (Zhang Min-Rui); He, ZQ (He Zheng-Quan); Wang, T (Wang Tao); Tian, JS (Tian Jin-Shou)
来源出版物: ACTA PHYSICA SINICA 卷: 66 期: 8 文献号: 084202 DOI: 10.7498/aps.66.084202 出版年: APR 20 2017
摘要: In most of the researches of polarization aberration, the influence of diattenuation is not large enough to affect imaging quality evidently. However, the modulation transfer function decreases when optical elements with complex planar dielectric structures and low transmittance, such as beam-splitter and optical modulator, are introduced into an imaging system. In this paper, a vector optical model in Descartes coordinate system is proposed based on the concept of vector plane wave spectrum (VPWS). The results of calculation show that the VPWS model is consistent with Debye model. Compared with Debye vector diffraction integral, the VPWS method is more suitable to the description of the PA introduced by planar optical device with opaque mask, such as larger surface quantum-confined-stark-effect electroabsorption modulator, which is used to modulate the light collected by optical antenna of time-of-flight (TOF) depth system or modulating-retroreflector free-space-optical communication system. In order to simplify the calculation and obtain the conclusion of the change in imaging quality directly, the formula of optical transfer function is decomposed into three parts (TE component, TM component and the correlation of them) instead of polynomial expansion of pupil function. The influences of diattenuation on MTF is studied globally and locally in a range of cut-off frequency of optical imaging system (2 N A/lambda). Allowance of diattenuation is analysed by numerical calculation, and a mathematical expression is derived. The result shows that the change of diattenuation can be neglected when the spatial frequency v is less than 0.2 N A /lambda, and the range of allowance decreases with the increase of spatial frequency. According to numerical calculation shown in Fig. 7 and the derived formulas (15) and (16), the ratios of reflection/transmission coefficient of s-light and p-light p root D-alpha ff should range respectively from 0.63 to 1.6(0.2 N A /lambda < v < 0.8 N A /lambda) and from 0.9 to 1.11(v > 0 : 8 N A /lambda) when the MTF is required to be not less than 90% of the value in ideal diffraction-limited system. The range of allowance becomes larger gradually with the increase of angle theta(n) between the normal of optical interface n and the optical axis of imaging system <^> z. If a polarization beam splitter is considered, p root D-alpha -> infinity, theta(n) /sin(-1) N A should be greater than 1-3.
入藏号: WOS:000402757400011
ISSN: 1000-3290
第 145 条,共 255 条
标题: Ultrafast all-optical solid-state framing camera with picosecond temporal resolution
作者: Gao, GL (Gao, Guilong); He, K (He, Kai); Tian, JS (Tian, Jinshou); Zhang, CM (Zhang, Chunmin); Zhang, J (Zhang, Jun); Wang, T (Wang, Tao); Chen, SR (Chen, Shaorong); Jia, H (Jia, Hui); Yuan, FF (Yuan, Fenfang); Liang, LL (Liang, Lingliang); Yan, X (Yan, Xin); Li, SH (Li, Shaohui); Wang, C (Wang, Chao); Yin, F (Yin, Fei)
来源出版物: OPTICS EXPRESS 卷: 25 期: 8 页: 8721-8729 DOI: 10.1364/OE.25.008721 出版年: APR 17 2017
摘要: A new ultrafast all-optical solid-state framing camera (UASFC) capable of single-shot ultrafast imaging is proposed and experimentally demonstrated. It is composed of an ultrafast semiconductor chip (USC), an optical time-series system (TSS), and a spatial mapping device (SMD) with an USC to transform signal beam information to the probe beam, a TSS to convert the time axis to wavelength-polarization, and a SMD to map wavelength-polarization image to different spatial positions. In our recent proof-of-principle experiment, better performance than ever of this technique is confirmed by giving six frames with similar to 3 ps temporal resolution and similar to 30 lp/mm spatial resolution. (C) 2017 Optical Society of America
入藏号: WOS:000400665200045
PubMed ID: 28437949
ISSN: 1094-4087
第 146 条,共 255 条
标题: Polarization-based enhancement of ocean color signal for estimating suspended particulate matter: radiative transfer simulations and laboratory measurements
作者: Liu, J (Liu, Jia); He, XQ (He, Xianqiang); Liu, JH (Liu, Jiahang); Bai, Y (Bai, Yan); Wang, DF (Wang, Difeng); Chen, TQ (Chen, Tieqiao); Wang, YH (Wang, Yihao); Zhu, F (Zhu, Feng)
来源出版物: OPTICS EXPRESS 卷: 25 期: 8 页: A323-A337 DOI: 10.1364/OE.25.00A323 出版年: APR 17 2017
摘要: Absorption and scattering by molecules, aerosols and hydrosols, and the reflection and transmission over the sea surface can modify the original polarization state of sunlight. However, water-leaving radiance polarization, containing embedded water constituent information, has largely been neglected. Here, the efficiency of the parallel polarization radiance (PPR) for enhancing ocean color signal of suspended particulate matter is examined via vector radiative transfer simulations and laboratory experiments. The simulation results demonstrate that the PPR has a slightly higher ocean color signal at the top-of-atmosphere as compared with that of the total radiance. Moreover, both the simulations and laboratory measurements reveal that, compared with total radiance, PPR can effectively enhance the normalized ocean color signal for a large range of observation geometries, wavelengths, and suspended particle concentrations. Thus, PPR has great potential for improving the ocean color signal detection from satellite. (C) 2017 Optical Society of America
入藏号: WOS:000400665200010
PubMed ID: 28437919
ISSN: 1094-4087
第 147 条,共 255 条
标题: A novel generation scheme of ultra-short pulse trains with multiple wavelengths
作者: Su, YL (Su, Yulong); Hu, H (Hu, Hui); Feng, H (Feng, Huan); Li, L (Li, Lu); Han, BA (Han, Biao); Wen, Y (Wen, Yu); Wang, YS (Wang, Yishan); Si, JH (Si, Jinhai); Xie, XP (Xie, Xiaoping); Wang, WQ (Wang, Weiqiang)
来源出版物: OPTICS COMMUNICATIONS 卷: 389 页: 176-180 DOI: 10.1016/j.optcom.2016.12.044 出版年: APR 15 2017
摘要: We demonstrate a novel scheme based on active mode locking combined with four-wave mixing (FWM) to generate ultra-short pulse trains at high repetition rate with multiple wavelengths for applications in various fields. The obtained six wavelengths display high uniformity both in temporal and frequency domain. Pulses at each wavelength are mode locked with pulse duration of similar to 44.37 ps, signal-to-noise ratio (SNR) of similar to 47.89 dB, root-mean-square (RMS) timing jitter of similar to 552.7 fs, and the time-bandwidth product of similar to 0.68 at repetition rate of 1 GHz. The experimental results show this scheme has promising usage in optical communications, optical networks, and fiber sensing.
入藏号: WOS:000393012900030
ISSN: 0030-4018
eISSN: 1873-0310
第 148 条,共 255 条
标题: Efficient modulation of orthogonally polarized infrared light using graphene metamaterials
作者: Cui, YD (Cui, Yudong); Zeng, C (Zeng, Chao)
来源出版物: JOURNAL OF APPLIED PHYSICS 卷: 121 期: 14 文献号: 143102 DOI: 10.1063/1.4980029 出版年: APR 14 2017
摘要: We propose an efficient modulation of linearly polarized infrared light using graphene metamaterials (GMMs) by exploiting the phase-coupled plasmon-induced transparency (PIT) mechanism. Because of the phase-coupling effect in GMMs, pronounced PIT peaks can be simultaneously obtained for the orthogonally polarized light through tuning of the Fermi level in graphene. Taking advantage of such polarization-selective PIT spectral responses and precise phase management, a dual-polarization GMM modulator is successfully achieved with ultra-high modulation depths of similar to 32 dB at 10 mu m and similar to 28 dB at 12.45 mu m for the x- and y-polarized light beams, respectively. The underlying principle of the proposal is well explained and verified by using transfer matrix method. The proposed scheme provides new opportunities for developing graphene-integrated high-performance electro-optical modulation, switching, and other optoelectronics applications. Published by AIP Publishing.
入藏号: WOS:000399071900002
ISSN: 0021-8979
eISSN: 1089-7550
第 149 条,共 255 条
标题: A novel ZVS high voltage power supply for micro-channel plate photomultiplier tubes
作者: Pei, CQ (Pei, Chengquan); Tian, JS (Tian, Jinshou); Liu, Z (Liu, Zhen); Qin, H (Qin, Hong); Wu, SL (Wu, Shengli)
来源出版物: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 卷: 851 页: 43-49 DOI: 10.1016/j.nima.2017.01.044 出版年: APR 11 2017
摘要: A novel resonant high voltage power supply (HVPS) with zero voltage switching (ZVS), to reduce the voltage stress on switching devices and improve conversion efficiency, is proposed. The proposed HVPS includes a drive circuit, a transformer, several voltage multiplying circuits, and a regulator circuit. The HVPS contains several secondary windings that can be precisely regulated. The proposed HVPS performed better than the traditional resistor voltage divider, which requires replacing matching resistors resulting in resistor dispersibility in the Micro-Channel Plate (MCP). The equivalent circuit of the proposed HVPS was established and the operational principle analyzed. The entire switching element can achieve ZVS, which was validated by a simulation and experiments. The properties of this HVPS were tested including minimum power loss (240 mW), maximum power loss (1 W) and conversion efficiency (85%). The results of this research are that the proposed HVPS was suitable for driving the micro-channel plate photomultiplier tube (MCP-PMT). It was therefore adopted to test the MCP-PMT, which will be used in Daya Bay reactor neutrino experiment II in China.
入藏号: WOS:000398007800009
ISSN: 0168-9002
eISSN: 1872-9576
第 150 条,共 255 条
标题: A method to measure the modulation transfer function of Bayer filter color camera
作者: Duan, YX (Duan Ya-Xuan); Liu, SK (Liu Shang-Kuo); Chen, YQ (Chen Yong-Quan); Xue, X (Xue Xun); Zhao, JK (Zhao Jian-Ke); Gao, LM (Gao Li-Min)
来源出版物: ACTA PHYSICA SINICA 卷: 66 期: 7 文献号: 074204 DOI: 10.7498/aps.66.074204 出版年: APR 5 2017
摘要: With the development of optoelectronic technologies, color cameras have been widely exploited in space remote sensing, earth observations from space, environmental monitoring, urban construction, and many other fields. Currently, most commercial color cameras use a single charge coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) sensor that has a Bayer color filter array (CFA) on its pixel surface to obtain red (R), green (G), or blue (B) samples. As a way of evaluating imaging quality, modulation transfer function (MTF) can provide a comprehensive and objective metric for camera imaging performance. In the conventional knife-edge method for color camera MTF measurement, a linear uniform sampling of the edge spread function (ESF) must be completed before a fast Fourier transform (FFT) can be applied. As the sampling rate becomes large, the number of pixel points on the line which is parallel to the knife-edge become less. So taking average of the pixel points to obtain ESF can be strongly affected by the noise of sensor. Therefore it is necessary to balance the influences of sampling rate and sensor noise on the MTF measurement, and the recommended sampling rate is 4-6. When the tilt angle of knife-edge has an error, the non-uniform sampling ESF can be obtained by the slanted knife-edge method. This leads to a variation in the results of the camera MTF on a spatial frequency scale and early cut-off. The best MTF results of camera can be obtained by rotating knife-edge, calculating MTF power under different tilt angles of knife-edge, and finding the maximum MTF power. And we propose an algorithm for Bayer filter color camera MTF measurement. The algorithm processing includes extracting R, G, B colors of knife-edge images; projection; differential operation; Hanning window filtration; FFT; correction; weighting combination of R, G, B colors MTF; MTF power calculation; optimal tilt angle of knife-edge estimation. To verify the accuracy of the proposed method, the weighting response factors of R, G, B colors are calibrated and an experimental setup for color camera MTF measurement is established. The knife-edge target is rotated in angle steps of 0.02 degrees, and the MTF results are calculated under different tilt angles of knife-edge within +/- 0.1 degrees. surrounding the estimate position by the proposed algorithm. The maximum differences of MTF results between the proposed method and fringe target method are 0.061 (Nyquist frequency f(c)) and 0.043 (f(c)/2), respectively. The results show that by searching the optimal tilt angle of knife-edge, the effect of non-uniform sampling on MTF result of color camera can be eliminated. Compared with the conventional method, the proposed method is superior for the measurement of the super-sampled MTF of color camera. Meanwhile, this method can also be applied to MTF measurements of radiographic systems, such as X-ray imaging system and other systems.
入藏号: WOS:000402752100011
ISSN: 1000-3290

第 151 条,共 255 条
标题: Non-diffracting optical Bloch oscillations in hexagonal photonic lattices
作者: Liu, S (Liu, Sheng); Rao, BJ (Rao, Bingjie); Wang, MR (Wang, Meirong); Zhang, P (Zhang, Peng); Xiao, FJ (Xiao, Fajun); Gan, XT (Gan, Xuetao); Zhao, JL (Zhao, Jianlin)
来源出版物: OPTICS EXPRESS 卷: 25 期: 7 页: 7475-7482 DOI: 10.1364/OE.25.007475 出版年: APR 3 2017
摘要: Light beams undergoing optical Bloch oscillations (OBOs) in two-dimensional (2D) photonic lattices suffer from severe diffraction along the perpendicular direction to the oscillation plane. In this paper, we propose and demonstrate that such diffraction could be suppressed in hexagonal photonic lattices via sophisticated managements of the discrete diffraction. By positioning the Fourier spectrum of the beam to a special region in the Brillouin zone, the light driven by the OBO experiences normal and anomalous diffractions alternatively, leading to a non-diffracting propagation for a long distance. We show that nondiffracting OBOs can be implemented not only for Gaussian beam but also for other complex 2D beams including self- accelerating Airy beams and vortex beams. Our results provide novel insights into the diffraction or dispersion engineering of waves in periodic structures. (C) 2017 Optical Society of America
入藏号: WOS:000398536000029
PubMed ID: 28380869
ISSN: 1094-4087
第 152 条,共 255 条
标题: Stochastic resonance based on modulation instability in spatiotemporal chaos
作者: Han, J (Han, Jing); Liu, HJ (Liu, Hongjun); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu)
来源出版物: OPTICS EXPRESS 卷: 25 期: 7 页: 8306-8314 DOI: 10.1364/OE.25.008306 出版年: APR 3 2017
摘要: A novel dynamic of stochastic resonance in spatiotemporal chaos is presented, which is based on modulation instability of perturbed partially coherent wave. The noise immunity of chaos can be reinforced through this effect and used to restore the coherent signal information buried in chaotic perturbation. A theoretical model with fluctuations term is derived from the complex Ginzburg-Landau equation via Wigner transform. It shows that through weakening the nonlinear threshold and triggering energy redistribution, the coherent component dominates the instability damped by incoherent component. The spatiotemporal output showing the properties of stochastic resonance may provide a potential application of signal encryption and restoration. (C) 2017 Optical Society of America
入藏号: WOS:000398536000105
PubMed ID: 28380945
ISSN: 1094-4087
第 153 条,共 255 条
标题: High peak power actively Q-switched mid-infrared fiber lasers at 3 mu m
作者: Shen, YL (Shen, Yanlong); Wang, YS (Wang, Yishan); Luan, KP (Luan, Kunpeng); Chen, HW (Chen, Hongwei); Tao, MM (Tao, Mengmeng); Si, JH (Si, Jinhai)
来源出版物: APPLIED PHYSICS B-LASERS AND OPTICS 卷: 123 期: 4 文献号: 105 DOI: 10.1007/s00340-017-6684-0 出版年: APR 2017
摘要: Diode-pumped pulsed Er3+-doped ZBLAN fiber lasers at 2.8 mu m actively Q-switched by using an mechanical Q-switch with feedbacks of a protected gold mirror and a blazing grating were investigated, respectively. A pulse energy of 0.13 mJ and repetition rate of 10 kHz with a pulse width of 127.3 ns at 2.78 mu m was obtained when using a protected gold mirror as the feedback. By replacing the mirror with a blazing grating in Littrow configuration, the wavelength of the Q-switched pulse train was tunable with over 100 nm tuning range from 2.71 to 2.82 mu m and a linewidth of similar to 1.5 nm. A maxinmum pulse energy of up to 0.15 mJ and repetition rate of 10 kHz with a pulse width of 92.6 ns was achieved, yielding the maximum peak power of exceeding 1.6 kW. The pulse energy and peak power, to our knowledge, are the highest ever reported in the mid-infrared Q-switched fiber lasers.
入藏号: WOS:000401569400011
ISSN: 0946-2171
eISSN: 1432-0649
第 154 条,共 255 条
标题: 3 W narrow-linewidth ultra-short wavelength operation near 1707 nm in thulium-doped silica fiber laser with bidirectional pumping
作者: Xiao, XS (Xiao, Xusheng); Guo, HT (Guo, Haitao); Yan, ZJ (Yan, Zhijun); Wang, HS (Wang, Hushan); Xu, YT (Xu, Yantao); Lu, M (Lu, Min); Wang, YS (Wang, Yishan); Peng, B (Peng, Bo)
来源出版物: APPLIED PHYSICS B-LASERS AND OPTICS 卷: 123 期: 4 文献号: 135 DOI: 10.1007/s00340-017-6713-z 出版年: APR 2017
摘要: We have developed an ultra-short wavelength operation of all-fiber Tm-doped laser system, in which the laser system was structured in a FBGs based linear cavity with FBG associated bidirectional pump mechanism at 1550 nm. The laser yielded 3.15 W of continuous-wave output at 1706.75 nm with a narrow-linewidth of similar to 50 pm. A high reflectivity FBG (HR-FBG) at 1550 nm was used to reflect the residual pump light and achieve the bidirectional pump mechanism. The maximum slope efficiency was improved from 23.2% without HR-FBG to 42.1% with HR-FBG at 1550 nm and the lowest pump threshold was reduced from 1.6 to 0.8 W accordingly. In the experiment, we have also investigated the dependencies of the slope efficiencies and pump threshold of the laser versus the length of active fiber and reflectivity of the output mirror (FBG) in detail. It is indisputable that the development of 1.7 mu m silicate fiber lasers with Watt-level output power will open up a number of promising application windows.
入藏号: WOS:000401569400041
ISSN: 0946-2171
eISSN: 1432-0649
第 155 条,共 255 条
标题: Transfer process of LT-GaAs epitaxial films for on-chip terahertz antenna integrated device
作者: Guo, CY (Guo Chun-Yan); Xu, JX (Xu Jian-Xing); Peng, HL (Peng Hong-Ling); Ni, HQ (Ni Hai-Qiao); Wang, T (Wang Tao); Tian, JS (Tian Jin-Shou); Niu, ZC (Niu Zhi-Chuan); Wu, ZX (Wu Zhao-Xin); Zuo, J (Zuo Jian); Zhang, CL (Zhang Cun-Lin)
来源出版物: JOURNAL OF INFRARED AND MILLIMETER WAVES 卷: 36 期: 2 页: 220-+ DOI: 10.11972/j.issn.1001-9014.2017.02.016 出版年: APR 2017
摘要: A process for LT-GaAs used as photoconductive switch in epitaxial layer transfer of on-chip THz antenna integrated device was provided. Hall indicated resistivity of the epitaxial materials gained by MBE was about 10(6)Omega center dot cm. HNO3-NH4OH-H2O-C3H8O7 center dot H2O-H2O2-HCl and wet chemical etching were used to etch epitaxial materials grown by MBE. Gained the structure that 1.5 mu m LT-GaAs bounded with COP after lift-off of SI-GaAs and Al0.9Ga0.1As. AFM SEM and high-power microscope indicated that the structure was flat and smooth after lift-off. RMS = 2.28 nm. EDAX indicated there wasn't Al in this structure. It can be used to make photoconductive switch.
入藏号: WOS:000400884100016
ISSN: 1001-9014
第 156 条,共 255 条
标题: 1.5-MHz repetition rate passively Q-switched Nd: YVO4 laser based on WS2 saturable absorber
作者: Wang, X (Wang, Xi); Li, L (Li, Lu); Li, JP (Li, Jin-Ping); Wang, YG (Wang, Yong-Gang)
来源出版物: CHINESE PHYSICS B 卷: 26 期: 4 文献号: 044203 DOI: 10.1088/1674-1056/26/4/044203 出版年: APR 2017
摘要: A transmission-type tungsten disulfide (WS2) -based saturable absorber (SA) is fabricated and applied to passively Q-switched Nd: YVO4 laser. The WS2 nanosheets are deposited on a quartz substrate by the vertical evaporation method. By inserting the WS2 SA into the plano-concave laser cavity, we achieve 153-ns pulses with an average output power of 1.19W at 1064 nm. To the best of our knowledge, both of them are the best results among those obtained by the Q-switched solid-state lasers with WS2-based absorbers. The repetition rate ranges from 1.176 MHz to 1.578 MHz. As far as we know, it is the first time that MHz level Q-switched pulses have been generated in all solid state lasers based on low-dimensional materials so far.
入藏号: WOS:000400906300003
ISSN: 1674-1056
eISSN: 1741-4199
第 157 条,共 255 条
标题: Fabrication of micro hole array on the surface of CVD ZnS by scanning ultrafast pulse laser for antireflection
作者: Li, YP (Li, Yangping); Zhang, TH (Zhang, Tianhui); Fan, SL (Fan, Siling); Cheng, GH (Cheng, Guanghua)
来源出版物: OPTICAL MATERIALS 卷: 66 页: 356-360 DOI: 10.1016/j.optmat.2017.02.019 出版年: APR 2017
摘要: Chemical vapor deposited (CVD) ZnS is a promising long-wave infrared (8-12 mu m) window material. Yet antireflection is necessary since Fresnel reflection from its surface is high due to the high refractive index of ZnS. Sub-wavelength structured surface of micro hole array was fabricated on CVD ZnS by scanning ultrafast pulse laser ablation. The effects of beam profile, pulse width and beam power on the radius and morphology of the holes were studied. Gaussian beam can cause severe melted-resolidified layers around the hole, yet Bessel beam only resulted in thin ribbon around the hole. The picosecond Bessel laser is more suitable than femtosecond laser for ablating holes on ZnS. The radius of the holes increases with increasing the Bessel beam pulse width and the beam power. But larger power may cause circle grooves around the central holes. Ordered hole array was fabricated on single side of CVD ZnS and antireflection was realized. (C) 2017 Elsevier B.V. All rights reserved.
入藏号: WOS:000400200000056
ISSN: 0925-3467
eISSN: 1873-1252
第 158 条,共 255 条
标题: Preparation and optical properties of TeO2-BaO-ZnO-ZnF2 fluoro-tellurite glass for mid-infrared fiber Raman laser applications
作者: Li, J (Li, Jie); Xiao, XS (Xiao, Xusheng); Gu, SX (Gu, Shaoxuan); Xu, YT (Xu, Yantao); Zhou, ZG (Zhou, Zhiguang); Guo, HT (Guo, Haitao)
来源出版物: OPTICAL MATERIALS 卷: 66 页: 567-572 DOI: 10.1016/j.optmat.2017.03.006 出版年: APR 2017
摘要: A serial of novel fluoro-tellurite glasses with compositions of 60TeO(2)-20BaO-(20-x)ZnO-xZnF(2) (x = 0, 2, 4, 5 and 6 mol%) were prepared. The compositional dependences of glass structural evaluation, Raman gain coefficient, UV-Vis transmission spectrum, IR transmission spectrum, linear refractive index and third-order nonlinearity were analyzed. The results showed that the addition of 6 mol% ZnF2 can further improve the Raman gain coefficient to as well as 52 x 10(-11) cm/W and effectively decrease around 73% and 57% absorption coefficients respectively caused by free O-H groups (@3.3 gm) and hydrogen-bonded O-H groups (@4.5 gm) in glass. Addition of ZnF2 does not change the UV-Vis absorption edge, optical band gap energy and infrared region cut-off edge almost, while the linear refraction index and ultrafast third-nonlinearity show unmonotonic changes. These novel fluoro-tellurite glasses may be suitable candidates for using in mid-infrared Raman fiber laser and/or amplifier. (C) 2017 Elsevier B.V. All rights reserved.
入藏号: WOS:000400200000087
ISSN: 0925-3467
eISSN: 1873-1252
第 159 条,共 255 条
标题: 4.62 kW excellent beam quality laser output with a low-loss Yb/Ce co-doped fiber fabricated by chelate gas phase deposition technique
作者: Zheng, JK (Zheng, Jinkun); Zhao, W (Zhao, Wei); Zhao, BY (Zhao, Baoyin); Hou, CQ (Hou, Chaoqi); Li, Z (Li, Zhe); Li, G (Li, Gang); Gao, Q (Gao, Qi); Ju, P (Ju, Pei); Gao, W (Gao, Wei); She, SF (She, Shengfei); Wu, P (Wu, Peng); Li, WN (Li, Weinan)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 7 期: 4 页: 1259-1266 DOI: 10.1364/OME.7.001259 出版年: APR 1 2017
摘要: A high-power Yb/Ce co-doped double-clad fiber with low optical loss was successfully fabricated by an optimized chelate gas phase deposition technique. It exhibits a nearly homogenous distribution of Al, Ce and Yb ions in the fiber core region, which reduce the clustering. The core attenuation at 1080 nm and 1383 nm are 12 dB/km and 46 dB/km, respectively, indicating high optical performance with a low optical loss. The amplifier stage with this fiber delivers 4.62 kW excellent beam quality (M-2 = 1.67) laser output with a slope efficiency of 80.3%. The experimental results show that the chelate gas phase deposition technique is a prospective method to fabricate a Yb/Ce co-doped fiber with low optical loss, which is beneficial for acquiring multi-kilowatt continuous-wave fiber laser with excellent beam quality. (C) 2017 Optical Society of America
入藏号: WOS:000400487200015
ISSN: 2159-3930
第 160 条,共 255 条
标题: Two-dimensional simulation of argon dielectric barrier discharge excited by a Gaussian voltage at atmospheric pressure
作者: Xu, YG (Xu, Yonggang); Wang, J (Wang, Jing); Li, J (Li, Jing); Lei, BY (Lei, Bingying); Tang, J (Tang, Jie); Wang, YS (Wang, Yishan); Li, YF (Li, Yongfang); Zhao, W (Zhao, Wei); Duan, YX (Duan, Yixiang)
来源出版物: PHYSICS OF PLASMAS 卷: 24 期: 4 文献号: 043507 DOI: 10.1063/1.4979898 出版年: APR 2017
摘要: A two-dimensional self-consistent fluid model was employed to investigate the spatiotemporal characteristics of discharges in atmospheric pressure argon (Ar) dielectric barrier discharge driven by a Gaussian voltage. The simulation results show that a discharge with multiple current pulses occurs each half-cycle in the gas gap. A transition from the Townsend mode to the glow mode is observed with the increasing applied voltage each half-cycle at a lower driving frequency (7.5 kHz). It is also found that the glow mode survives all the discharge phases at a higher driving frequency (12.5 kHz and 40 kHz). The change in the discharge mode with the driving frequency mainly lies in the fact that a lot of charged particles created in the discharge gap have no enough time to drift and diffuse around, and then these particles are assembled in the discharge space at higher frequency. Additionally, the spatial distributions of the electron density indicate that a center-advantage discharge is ignited at the driving frequencies of interest, resulting in the radial non-uniformity of discharge because of the edge effects. However, this overall non-uniformity is weakened with the driving frequency increased to 40 kHz, at which concentric ring patterns are observed. These distinct behaviors are mainly attributed to the fact that many charged particles generated are trapped in the gas gap and then accumulated to make the extension along the radial direction due to the charged particles transport and diffusion, and that the effective overlapping of a large number of avalanches induced by the increased "seed" electron density with the driving frequency. Meanwhile, the surface charged particles accumulated on the dielectric barriers are also shown to play a role in the formation of the discharge structure. Published by AIP Publishing.
入藏号: WOS:000400390700091
ISSN: 1070-664X
eISSN: 1089-7674
第 161 条,共 255 条
标题: Cost-Optimized Microblog Distribution over Geo-Distributed Data Centers: Insights from Cross-Media Analysis
作者: Hu, H (Hu, Han); Wen, YG (Wen, Yonggang); Chua, TS (Chua, Tat-Seng); Li, XL (Li, Xuelong)
来源出版物: ACM TRANSACTIONS ON INTELLIGENT SYSTEMS AND TECHNOLOGY 卷: 8 期: 3 特刊: SI 文献号: 40 DOI: 10.1145/3014431 出版年: APR 2017
摘要: The unprecedent growth of microblog services poses significant challenges on network traffic and service latency to the underlay infrastructure ( i.e., geo-distributed data centers). Furthermore, the dynamic evolution in microblog status generates a huge workload on data consistence maintenance. In this article, motivated by insights of cross-media analysis-based propagation patterns, we propose a novel cache strategy for microblog service systems to reduce the inter-data center traffic and consistence maintenance cost, while achieving low service latency. Specifically, we first present a microblog classification method, which utilizes the external knowledge from correlated domains, to categorize microblogs. Then we conduct a large-scale measurement on a representative online social network system to study the category-based propagation diversity on region and time scales. These insights illustrate social common habits on creating and consuming microblogs and further motivate our architecture design. Finally, we formulate the content cache problem as a constrained optimization problem. By jointly using the Lyapunov optimization framework and simplex gradient method, we find the optimal online control strategy. Extensive trace-driven experiments further demonstrate that our algorithm reduces the system cost by 24.5% against traditional approaches with the same service latency.
入藏号: WOS:000400160800007
作者识别号:
作者        ResearcherID 号        ORCID 号
Wen, Yonggang         B-8848-2011         
ISSN: 2157-6904
eISSN: 2157-6912
第 162 条,共 255 条
标题: Large Sparse Cone Non-negative Matrix Factorization for Image Annotation
作者: Tao, DP (Tao, Dapeng); Tao, DC (Tao, Dacheng); Li, XL (Li, Xuelong); Gao, XB (Gao, Xinbo)
来源出版物: ACM TRANSACTIONS ON INTELLIGENT SYSTEMS AND TECHNOLOGY 卷: 8 期: 3 特刊: SI 文献号: 37 DOI: 10.1145/2987379 出版年: APR 2017
摘要: Image annotation assigns relevant tags to query images based on their semantic contents. Since Non-negative Matrix Factorization (NMF) has the strong ability to learn parts-based representations, recently, a number of algorithms based on NMF have been proposed for image annotation and have achieved good performance. However, most of the efforts have focused on the representations of images and annotations. The properties of the semantic parts have not been well studied. In this article, we revisit the sparseness-constrained NMF (sNMF) proposed by Hoyer [ 2004]. By endowing the sparseness constraint with a geometric interpretation and sNMF with theoretical analyses of the generalization ability, we show that NMF with such a sparseness constraint has three advantages for image annotation tasks: (i) The sparseness constraint is more l(0)-norm oriented than the l(0)-norm-based sparseness, which significantly enhances the ability of NMF to robustly learn semantic parts. (ii) The sparseness constraint has a large cone interpretation and thus allows the reconstruction error of NMF to be smaller, which means that the learned semantic parts are more powerful to represent images for tagging. (iii) The learned semantic parts are less correlated, which increases the discriminative ability for annotating images. Moreover, we present a new efficient large sparse cone NMF (LsCNMF) algorithm to optimize the sNMF problem by employing the Nesterov's optimal gradient method. We conducted experiments on the PASCAL VOC07 dataset and demonstrated the effectiveness of LsCNMF for image annotation.
入藏号: WOS:000400160800004
ISSN: 2157-6904
eISSN: 2157-6912
第 163 条,共 255 条
标题: Learning k for kNN Classification
作者: Zhang, SC (Zhang, Shichao); Li, XL (Li, Xuelong); Zong, M (Zong, Ming); Zhu, XF (Zhu, Xiaofeng); Cheng, DB (Cheng, Debo)
来源出版物: ACM TRANSACTIONS ON INTELLIGENT SYSTEMS AND TECHNOLOGY 卷: 8 期: 3 特刊: SI 文献号: 43 DOI: 10.1145/2990508 出版年: APR 2017
摘要: The K Nearest Neighbor (kNN) method has widely been used in the applications of data mining and machine learning due to its simple implementation and distinguished performance. However, setting all test data with the same k value in the previous kNN methods has been proven to make these methods impractical in real applications. This article proposes to learn a correlation matrix to reconstruct test data points by training data to assign different k values to different test data points, referred to as the Correlation Matrix kNN (CM-kNN for short) classification. Specifically, the least-squares loss function is employed to minimize the reconstruction error to reconstruct each test data point by all training data points. Then, a graph Laplacian regularizer is advocated to preserve the local structure of the data in the reconstruction process. Moreover, an l(1)-norm regularizer and an l(2,1)-norm regularizer are applied to learn different k values for different test data and to result in low sparsity to remove the redundant/noisy feature from the reconstruction process, respectively. Besides for classification tasks, the kNN methods (including our proposed CM-kNN method) are further utilized to regression and missing data imputation. We conducted sets of experiments for illustrating the efficiency, and experimental results showed that the proposed method was more accurate and efficient than existing kNN methods in data-mining applications, such as classification, regression, and missing data imputation.
入藏号: WOS:000400160800010
ISSN: 2157-6904
eISSN: 2157-6912
第 164 条,共 255 条
标题: The Gain and Time Characteristics of Microchannel Plates in Various Channel Geometries
作者: Chen, L (Chen, Lin); Wang, XC (Wang, Xingchao); Tian, JS (Tian, Jinshou); Zhao, TC (Zhao, Tianchi); Liu, CL (Liu, Chunliang); Liu, HL (Liu, Hulin); Wei, YL (Wei, Yonglin); Sai, XF (Sai, Xiaofeng); Wang, X (Wang, Xing); Sun, JN (Sun, Jianning); Si, SG (Si, Shuguang); Chen, P (Chen, Ping); Tian, LP (Tian, Liping); Hui, DD (Hui, Dandan); Guo, LH (Guo, Lehui)
来源出版物: IEEE TRANSACTIONS ON NUCLEAR SCIENCE 卷: 64 期: 4 页: 1080-1086 DOI: 10.1109/TNS.2017.2676010 出版年: APR 2017
摘要: Microchannel plates (MCPs) are widely used as electron, ion, and X-ray detectors. The gain factor and time resolution of the MCP are strongly dependent on its operating and geometry parameters (applied voltage, length-to-diameter ratio, bias angle, and electrode penetration depth). Measurements about this dependence are sparse and do not cover the full range of the parameters. In this paper, 3-D single channel models are developed in computer simulation technology studio suit to systematically and comprehensively calculate the MCP gain and time resolution for various operating and geometry parameters. Furman secondaries electron emission model is employed in our simulation. Simulated result of the gain versus bias voltage is validated by the available experimental data. Finally, geometry parameters of L = 373.6 mu m, D = 10 mu m, h(in) = h(out) = 5 mu m, and theta = 12 degrees are proposed to optimize the MCP performances. Simulation results show that the gain, mean transit time, and transit time spread of the optimized MCP are expected to reach 128 012, 128 ps and 19 ps at the applied voltage of 1000 V.
入藏号: WOS:000399748600010
ISSN: 0018-9499
eISSN: 1558-1578
第 165 条,共 255 条
标题: Few-layered MoS2 as a saturable absorber for a passively Q-switched Er: YAG laser at 1.6 mu m
作者: Xia, HW (Xia, Hongwang); Li, M (Li, Ming); Li, T (Li, Tao); Zhao, SZ (Zhao, Shengzhi); Li, GQ (Li, Guiqiu); Yang, KJ (Yang, Kejian)
来源出版物: APPLIED OPTICS 卷: 56 期: 10 页: 2766-2770 DOI: 10.1364/AO.56.002766 出版年: APR 1 2017
摘要: The passively Q-switched Er: YAG laser at 1.6 mu m was achieved with a YAG-based MoS2 saturable absorber (SA) for the first time. The saturable absorption properties of the MoS2 SA near 1.6 mu m were investigated. Under an absorbed pump power of 8.09 W, an average output power of 1.08 W with a pulse duration of 1.138 mu s and a repetition rate of 46.6 kHz was obtained, corresponding to an optical conversion efficiency of 40.67%. The pulse energy and peak power were calculated to be 23.08 mu J and 20.28 W, respectively. (C) 2017 Optical Society of America
入藏号: WOS:000398174500025
PubMed ID: 28375238
ISSN: 1559-128X
eISSN: 2155-3165
第 166 条,共 255 条
标题: Effect of thermally induced birefringence on performance of KD*P electro-optics crystal with rectangular shape
作者: Yin, XL (Yin, Xingliang); Jiang, MH (Jiang, Menghua); Sun, Z (Sun, Zhe); Hui, YL (Hui, Yongling); Lei, H (Lei, Hong); Li, Q (Li, Qiang)
来源出版物: APPLIED OPTICS 卷: 56 期: 10 页: 2893-2900 DOI: 10.1364/AO.56.002893 出版年: APR 1 2017
摘要: In this paper, we present what we believe is the first demonstration of a new rectangular KD*P crystal as an electro-optic switch and calculations of the stress-induced birefringence and depolarization loss in the crystal. We simulated and experimentally demonstrate the thermal depolarization loss of crystal in both cylindrical and rectangular shape. The results show that by using a rectangular KD*P crystal, the effects of the thermally induced birefringence and depolarization can be lessened. (C) 2017 Optical Society of America
入藏号: WOS:000398174500044
PubMed ID: 28375258
ISSN: 1559-128X
eISSN: 2155-3165
第 167 条,共 255 条
标题: Orthogonal self-guided similarity preserving projection for classification and clustering
作者: Fang, XZ (Fang, Xiaozhao); Xu, Y (Xu, Yong); Li, XL (Li, Xuelong); Lai, ZH (Lai, Zhihui); Teng, SH (Teng, Shaohua); Fei, LK (Fei, Lunke)
来源出版物: NEURAL NETWORKS 卷: 88 页: 1-8 DOI: 10.1016/j.neunet.2017.01.001 出版年: APR 2017
摘要: A suitable feature representation can faithfully preserve the intrinsic structure of data. However, traditional dimensionality reduction (DR) methods commonly use the original input features to define the intrinsic structure, which makes the estimated intrinsic structure unreliable since redundant or noisy features may exist in the original input features. Thus a dilemma is that (1) one needs the most suitable feature representation to define the intrinsic structure of data and (2) one should use the proper intrinsic structure of data to perform feature extraction. To address the problem, in this paper we propose a unified learning framework to simultaneously obtain the optimal feature representation and intrinsic structure of data. The structure is learned from the results of feature learning, and the features are learned to preserve the refined structure of data. By leveraging the interactions between the process of determining the most suitable feature representation and intrinsic structure of data, we can capture accurate structure and obtain the optimal feature representation of data. Experimental results demonstrate that our method outperforms state-of-the-art methods in DR and subspace clustering. The code of the proposed method is available at "http://www.yongxu.org/lunwen.html''. (C) 2017 Elsevier Ltd. All rights reserved.
入藏号: WOS:000397959900001
PubMed ID: 28161499
ISSN: 0893-6080
eISSN: 1879-2782
第 168 条,共 255 条
标题: Nanosecond passively Q-switched Nd: YVO4 laser based on WS2 saturable absorber
作者: Wang, X (Wang, Xi); Li, L (Li, Lu); Wang, YG (Wang, Yonggang); Zhang, L (Zhang, Ling); Wen, Q (Wen, Qiao); Yang, GW (Yang, Guowen)
来源出版物: LASER PHYSICS 卷: 27 期: 4 文献号: 045802 DOI: 10.1088/1555-6611/aa5f90 出版年: APR 2017
摘要: We report on a nanosecond pulse generation in a diode end-pumped passively Q-switched Nd: YVO4 laser using a tungsten disulfide (WS2) solution saturable absorber (SA). The WS2 suspension is fabricated by the liquid-phase-exfoliated method and injected into a quartz cell for the use of SA. Compared with solid absorber, such solution absorber has the virtues of good optical transparency, high heat dissipation and long term stability. By inserting the WS2 solution SA in the laser cavity, a stable Q-switched laser operation centered at 1064.45 nm wavelength is obtained with the shortest pulse duration of 788 ns and corresponding repetition rate of 333.5 kHz. The maximum average output power is registered to be 720 mW with the slope efficiency of 7.8%. To the best of our knowledge, it is the highest output power so far among pulsed lasers based on transition metal dichalcogenides (TMDs) SAs. The results demonstrate that WS2 solution absorber is a promising saturable absorber for the generation of high output power pulsed lasers.
入藏号: WOS:000395982200001
ISSN: 1054-660X
eISSN: 1555-6611
第 169 条,共 255 条
标题: Joint Dictionary Learning for Multispectral Change Detection
作者: Lu, XQ (Lu, Xiaoqiang); Yuan, Y (Yuan, Yuan); Zheng, XT (Zheng, Xiangtao)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 47 期: 4 页: 884-897 DOI: 10.1109/TCYB.2016.2531179 出版年: APR 2017
摘要: Change detection is one of the most important applications of remote sensing technology. It is a challenging task due to the obvious variations in the radiometric value of spectral signature and the limited capability of utilizing spectral information. In this paper, an improved sparse coding method for change detection is proposed. The intuition of the proposed method is that unchanged pixels in different images can be well reconstructed by the joint dictionary, which corresponds to knowledge of unchanged pixels, while changed pixels cannot. First, a query image pair is projected onto the joint dictionary to constitute the knowledge of unchanged pixels. Then reconstruction error is obtained to discriminate between the changed and unchanged pixels in the different images. To select the proper thresholds for determining changed regions, an automatic threshold selection strategy is presented by minimizing the reconstruction errors of the changed pixels. Adequate experiments on multispectral data have been tested, and the experimental results compared with the state- of- the- art methods prove the superiority of the proposed method. Contributions of the proposed method can be summarized as follows: 1) joint dictionary learning is proposed to explore the intrinsic information of different images for change detection. In this case, change detection can be transformed as a sparse representation problem. To the authors' knowledge, few publications utilize joint learning dictionary in change detection; 2) an automatic threshold selection strategy is presented, which minimizes the reconstruction errors of the changed pixels without the prior assumption of the spectral signature. As a result, the threshold value provided by the proposed method can adapt to different data due to the characteristic of joint dictionary learning; and 3) the proposed method makes no prior assumption of the modeling and the handling of the spectral signature, which can be adapted to different data.
入藏号: WOS:000396396700006
PubMed ID: 26955060
作者识别号:
作者        ResearcherID 号        ORCID 号
Lu, Xiaonan                  0000-0002-0920-1939
ISSN: 2168-2267
eISSN: 2168-2275
第 170 条,共 255 条
标题: Mesoporous SiO2/VO2 double-layer thermochromic coating with improved visible transmittance for smart window
作者: Zhang, J (Zhang, Jing); Wang, J (Wang, Jing); Yang, CM (Yang, Chunming); Jia, HB (Jia, Hongbao); Cui, XM (Cui, Xinmin); Zhao, SC (Zhao, Shichao); Xu, Y (Xu, Yao)
来源出版物: SOLAR ENERGY MATERIALS AND SOLAR CELLS 卷: 162 页: 134-141 DOI: 10.1016/j.solmat.2016.12.048 出版年: APR 2017
摘要: Thermochromic vanadium dioxide (VO2) film is a potential material for smart-window. But the high refractive index ( > 2) of VO2 coating in visible band resulted in strong reflection and low visible transmission. If another coating with a definite low refractive index is laid on VO2 film to construct a gradient index multilayer system, the total reflection could be effectively reduced. Therefore in this paper we designed a mesoporous SiO2/VO2 double-layer system in which the mesoporous SiO2 layer possessed an index adjustable from 1.243 to 1.354 to reduce the surface reflection of VO2-based smart window. The mesoporous structure has been investigated through several techniques including 2D GISAXS, TEM and N-2 ad/desorption. More important, a facile, safe and low-cost solution method was employed to prepare VO2 film with 60 nm thickness directly from ammonium citrato-oxovanadate (IV) compound that was reported by us previously. On this newly designed mesoporous SiO2/VO2 double-layer coating, the integral visible transmittance at 25 degrees C (T-vis,L) increased to 80.0% from 69.8% of pure VO2 coating while the corresponsive integral visible transmittance at 90 degrees C (T-vis,T-H) increased to 78.9% from 67.6% of pure VO2 coating, if the index of mesoporous SiO2 layer was optimized to 1.299. Simultaneously, the near infrared switching ability at 2000 nm (Delta T-2000) reached 29.0% and solar energy modulation (Delta T-sol) was maintained at 10.2%. The phase transition temperatures (T-t) for VO2 coating and the optimized SiO2/VO2 double-layer coating were 51.9 degrees C and 53.8 degrees C respectively, far below 68 degrees C of bulky VO2. This optical performance should be very attractive for application in the further smart window because of little increased cost and greatly enhanced property.
入藏号: WOS:000393720500017
ISSN: 0927-0248
eISSN: 1879-3398
第 171 条,共 255 条
标题: Glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals for frequency conversion of lasers
作者: Fang, ZJ (Fang, Zaijin); Xiao, XS (Xiao, Xusheng); Wang, X (Wang, Xin); Ma, ZJ (Ma, Zhijun); Lewis, E (Lewis, Elfed); Farrell, G (Farrell, Gerald); Wang, PF (Wang, Pengfei); Ren, J (Ren, Jing); Guo, HT (Guo, Haitao); Qiu, JR (Qiu, Jianrong)
来源出版物: SCIENTIFIC REPORTS 卷: 7 文献号: 44456 DOI: 10.1038/srep44456 出版年: MAR 30 2017
摘要: A glass-ceramic optical fiber containing Ba2TiSi2O8 nanocrystals fabricated using a novel combination of the melt-in-tube method and successive heat treatment is reported for the first time. For the melt-in-tube method, fibers act as a precursor at the drawing temperature for which the cladding glass is softened while the core glass is melted. It is demonstrated experimentally that following heat treatment, Ba2TiSi2O8 nanocrystals with diameters below 10 nm are evenly distributed throughout the fiber core. Comparing to the conventional rod-in-tube method, the melt-in-tube method is superior in terms of controllability of crystallization to allow for the fabrication of low loss glass-ceramic fibers. When irradiated using a 1030 nm femtosecond laser, an enhanced green emission at a wavelength of 515 nm is observed in the glass-ceramic fiber, which demonstrates second harmonic generation of a laser action in the fabricated glass-ceramic fibers. Therefore, this new glass-ceramic fiber not only provides a highly promising development for frequency conversion of lasers in all optical fiber based networks, but the melt-in-tube fabrication method also offers excellent opportunities for fabricating a wide range of novel glass-ceramic optical fibers for multiple future applications including fiber telecommunications and lasers.
入藏号: WOS:000397813900001
PubMed ID: 28358045
ISSN: 2045-2322
第 172 条,共 255 条
标题: A hydrophobic and abrasion-resistant MgF2 coating with an ultralow refractive index for double-layer broadband antireflective coatings
作者: Cui, XM (Cui, Xinmin); Ding, RM (Ding, Ruimin); Wang, MC (Wang, Mengchao); Wang, CH (Wang, Conghui); Zhang, J (Zhang, Jing); Wang, J (Wang, Jing); Dong, WS (Dong, Wensheng); Xu, Y (Xu, Yao)
来源出版物: JOURNAL OF MATERIALS CHEMISTRY C 卷: 5 期: 12 页: 3088-3096 DOI: 10.1039/c6tc05307f 出版年: MAR 28 2017
摘要: An ultralow-index top layer is a prerequisite to preparing high-performance broadband AR coatings. When coupled with hydrophobicity and the abrasion-resistance required in practical applications, the challenge becomes even greater. In this work, a MgF2 AR coating was studied because of the low refractive index of MgF2 and its easily realized strong adhesion through low-temperature heat treatment. In order to obtain an ultralow refractive index and endow the coating with hydrophobicity, we designed several experimental routes and finally adopted MTES/TEOS co-precursors to direct MgF2 particles to form a honeycomb-like network structure without a template. A final refractive index of 1.15 and good hydrophobicity, with a water contact angle of 1221, were obtained using the MgF2-SiO2(CH3) coating. These superior properties were attributed to the incorporation of methyl groups, which not only endowed the coating with hydrophobicity, but also changed the original linear assembly of MgF2 particles to a circular assembly. Using this hydrophobic ultralow-index coating as a top layer, a high-performance double-layer AR coating was fabricated with a high average transmittance of 99.43% in the wavelength range of 400-1000 nm, good abrasion-resistance, and damp heat resistance after a low-temperature heat treatment of 250 degrees C. This MgF2 double-layer AR coating may be used in display devices or lenses.
入藏号: WOS:000397963500013
ISSN: 2050-7526
eISSN: 2050-7534
第 173 条,共 255 条
标题: Several nanosecond Nd:YVO4 lasers Q-switched by two dimensional materials: tungsten disulfide, molybdenum disulfide, and black phosphorous
作者: Liu, H (Liu, Huan); Sun, Z (Sun, Zhe); Wang, X (Wang, Xi); Wang, YG (Wang, Yonggang); Cheng, GH (Cheng, Guanghua)
来源出版物: OPTICS EXPRESS 卷: 25 期: 6 页: 6244-6252 DOI: 10.1364/OE.25.006244 出版年: MAR 20 2017
摘要: Graphene-like two-dimensional (2D) materials have shown remarkable broadband saturable absorption properties. These materials were successfully applied into mode locked lasers to generate laser pulses with the pulse duration from picosecond to femtosecond. However, these novel materials have not shown good performance as far in another important aspect: Q-switched lasers. Solid-state or fiber lasers Q-switched with broadband absorbers usually generated pulses of one hundred nanosecond to several microsecond, which show weak competitiveness compared to traditional absorbers such as Cr: YAG and semiconductor saturable absorption mirror (SESAM). In this paper we utilized BP, WS2 and MoS2 solutions as saturable absorbers (SAs) to construct the passively Q-switched Nd:YVO4 lasers. The pulse durations as short as 2.86 nanosecond was obtained. To the best of our knowledge, it was the first report that the pulse durations approached several nanosecond level in Q-switched lasers with liquid-form of BP, WS2 and MoS2 SAs. (C) 2017 Optical Society of America
入藏号: WOS:000397316200034
PubMed ID: 28380977
ISSN: 1094-4087
第 174 条,共 255 条
标题: Modeling and research of a space-based spacecraft infrared detection system
作者: Li, WH (Li, Wenhao); Liu, ZH (Liu, Zhaohui); Mu, Y (Mu, You); Yang, R (Yang, Rui); Zhang, X (Zhang, Xing)
来源出版物: APPLIED OPTICS 卷: 56 期: 9 页: 2428-2433 DOI: 10.1364/AO.56.002428 出版年: MAR 20 2017
摘要: When a spacecraft is in orbit, it is almost impossible to check its working condition. Almost all payload would generate waste heat when working, which is usually ejected by a radiator. By observing the radiator, we can catch a glimpse of a spacecraft's inner information. A thorough model of a space-based infrared detection system is analyzed, taking the radiator into account, which, to the best of our knowledge, has seldom been considered. The calculation result shows that infrared radiation reflected by spacecraft is weak compared with the spacecraft's self-radiation in 8-12 mu m, and the contrast ratio between the radiator and surrounding area could be the criterion for judging the working condition of a spacecraft. The limit of detection distance is also increased due the higher temperature of the radiator. (C) 2017 Optical Society of America
入藏号: WOS:000398087100028
PubMed ID: 28375348
ISSN: 1559-128X
eISSN: 2155-3165
第 175 条,共 255 条
标题: Electron optics design of an 8-in. spherical MCP-PMT
作者: Chen, P (Chen, Ping); Tian, JS (Tian, Jinshou); Qian, S (Qian, Sen); Zhao, TC (Zhao, Tianchi); Liu, HL (Liu, Hulin); Wei, YL (Wei, Yonglin); Sai, XF (Sai, Xiaofeng); He, JP (He, Jianping); Wang, X (Wang, Xing); Lu, Y (Lu, Yu); Chen, L (Chen, Lin); Guo, LH (Guo, Lehui); Pei, CQ (Pei, Chengquan); Hui, DD (Hui, Dandan)
来源出版物: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 卷: 848 页: 1-8 DOI: 10.1016/j.nima.2016.11.054 出版年: MAR 11 2017
摘要: This paper discusses the electron optical system of an 8-in. spherical MCP-PMT. The MCP assembly, the supporting pole and the supply voltages are carefully designed to optimize the photoelectron collection efficiency and the transit time spread. Coating the MCP nickel-chromium electrode with an additional high secondary emission material is employed to make a breakthrough on the collection efficiency. With the simulation software CST, the Finite Integration method and the Monte Carlo method are combined to evaluate the collection efficiency, the time properties and the Earth's magnetic field effects. Simulation results show that the photocathode active solid angle is over 3.5 pi sr, the average collection efficiency can exceed 95% with the coated MCP and the mean transit time spread is 2.2 ns for a typical electric potential of 500 V applied between the photocathode and the MCP input facet. The prototype and the measured single photoelectron spectrum are also presented.
入藏号: WOS:000394627600001
ISSN: 0168-9002
eISSN: 1872-9576
第 176 条,共 255 条
标题: Mid-infrared transmitter and receiver modules for free-space optical communication
作者: Hao, Q (Hao, Qiang); Zhu, GS (Zhu, Guoshen); Yang, S (Yang, Song); Yang, KW (Yang, Kangwen); Duan, T (Duan, Tao); Xie, XP (Xie, Xiaoping); Huang, K (Huang, Kun); Zeng, HP (Zeng, Heping)
来源出版物: APPLIED OPTICS 卷: 56 期: 8 页: 2260-2264 DOI: 10.1364/AO.56.002260 出版年: MAR 10 2017
摘要: We report on the experimental implementation of single-frequency fiber-laser pumped mid-infrared (mid-IR) transmitter and receiver modules for free-space communications. These modules enable frequency upconversion and downconversion between the 1550-nm telecom wavelength and the mid-IR, thus providing essential free-space transmission links with mid-IR single-frequency lasers in the 3.6 mu m region. Specifically, based on difference frequency generation (DFG) in MgO-doped periodically poled LiNbO3 (MgO: PPLN), the mid-IR transmitter produces 9.3-mW power at 3594 nm with 5-W pump power at 1083 nm (< 10 kHz linewidth) and 3-W signal power at 1550 nm (< 10 kHz linewidth), and the mid-IR receiver reproduces 12-mu W power at 1550 nm with 4.7-W pump power at 1083 nm and 5-mW laser at 3594 nm. The whole modules are integrated into portable and compact devices by incorporating single-frequency fiber lasers, fiber amplifiers, DFG units, and related electronic circuits. In addition, the uses of all polarization-maintaining fiber configuration and wellcontrolled heat dissipation make the mid-IR transmitter and receiver exhibit a long-term stability. (C) 2017 Optical Society of America
入藏号: WOS:000396227500032
PubMed ID: 28375270
ISSN: 1559-128X
eISSN: 2155-3165
第 177 条,共 255 条
标题: Beam dynamics in disordered PT-symmetric optical lattices based on eigenstate analyses
作者: Yao, XK (Yao, Xiankun); Liu, XM (Liu, Xueming)
来源出版物: PHYSICAL REVIEW A 卷: 95 期: 3 文献号: 033804 DOI: 10.1103/PhysRevA.95.033804 出版年: MAR 7 2017
摘要: Wave functions will experience a localization process when evolving in disordered lattices. Here, we have demonstrated the effects of disordered PT-symmetric potentials on wave- function characteristics in optics based on eigenstate analyses. In weak- disorder cases, by using the tight-binding approximation method, a conclusion is obtained that the increasing of the imaginary part of potential can enhance the diffraction, while the increasing disorder will block the diffraction and lead to localization. In the general case, band theory is used for band-structure analysis of three bands. We find that the disorder has a smaller effect on the higher- order band, which is proved by the beam evolutions. Our work may be instructive for realizing beam path control by manipulating the strengths of disorder and gain and/ or loss of lattice.
入藏号: WOS:000395982100009
ISSN: 2469-9926
eISSN: 2469-9934
第 178 条,共 255 条
标题: Development and performance test of dynamic simulation system for X-ray pulsar navigation
作者: Xu, N (Xu Neng); Sheng, LZ (Sheng Li-Zhi); Zhang, DP (Zhang Da-Peng); Chen, C (Chen Chen); Zhao, BS (Zhao Bao-Sheng); Zheng, W (Zheng Wei); Liu, CL (Liu Chun-Liang)
来源出版物: ACTA PHYSICA SINICA 卷: 66 期: 5 文献号: 059701 DOI: 10.7498/aps.66.059701 出版年: MAR 5 2017
摘要: X-ray pulsar navigation is a complete autonomous navigation system, which has broad application prospects. Because of the huge cost of the navigation system, the implementation of ground simulation system is essential to the application of X-ray pulsar navigation. At present, most of researches on the semi physical experiment system are static. The aim of this article is to develop the dynamic simulation experiment system as well as its performance test. Specifically, this system consists of the dynamic signal database, X-ray simulation source, vacuum system and detection system designed for different science purposes. The core component of the X-ray source is the gate controlled X-ray tube, which can simulate the pulse profile of arbitrary waveform. The detecting system is based on the silicon drift detector with high time response capability. It uses trapezoidal shape for signal processing, and the timing resolution of the detection system is better than 2 mu s. In addition, the dynamic signal generation method is given by analyzing the time transformation model while the SINC interpolation method is provided to generate the dynamic pulse profile. Finally, the spacecraft revolving around the earth for a circle and receiving a pulse signal of Crab is simulated. In the simulation, the orbital radius of satellite is 6578 km and the orbital period is 5400 s. The Crab pulsar is selected, and the pulse period is 33.4 ms, the number of photons received by the detector is 200 per second. As a contrast, a set of static experiments is also performed. The correlation coefficient between the cumulative pulse profile and the standard pulse profile is 0.9953. However, the correlation coefficient decreases gradually, from 0.9094 at 300 s to 0.4080 at 5400 s, in the dynamic experiment. Then, the pulse period is searched from the arrival time of photons. The periodicity of the pulse signal is sinusoidal when the search period is 60 s. The change rate of photon flux is less than 2%, and the influence on the period search is negligible. The variation of pulse period is consistent with the motion law of spacecraft, which indicates that spacecraft motion is the dominant factor in time conversion. Finally, the arrival time of photons is transformed into the time at the solar system barycenter, indicating that the correlation coefficient between cumulative pulse profile and standard pulse profile is 0.9882. The result shows that the simulation system can simulate the X-ray pulse signal received by the spacecraft in orbit, which can provide the experimental basis for verifying the navigation algorithm and calibrating the detector performance.
入藏号: WOS:000398071700039
ISSN: 1000-3290
第 179 条,共 255 条
标题: All-Optical Wavelength Conversion Based on Four-Wave Mixing in Dispersion-Engineered Silicon Nanowaveguides
作者: Wang, ZL (Wang, Zhaolu); Liu, HJ (Liu, Hongjun); Sun, QB (Sun, Qibing); Huang, N (Huang, Nan); Han, J (Han, Jing)
来源出版物: JOURNAL OF RUSSIAN LASER RESEARCH 卷: 38 期: 2 页: 204-210 DOI: 10.1007/s10946-017-9635-7 出版年: MAR 2017
摘要: We demonstrate experimentally all-optical wavelength conversion based on four-wave mixing in dispersion-engineered silicon nanowaveguides with a picosecond pulse pump. We find that the conversion efficiency is significantly limited by nonlinear losses induced by the two-photon absorption and freecarrier absorption. Using a picosecond pulse pump centered at 1,550 nm, we show that the input continuous-wave signals can efficiently be converted into a broadband idler pulse in silicon waveguides with various dimensions. Conversion efficiencies versus signal wavelengths are different for silicon waveguides with different dimensions due to the variation in the phase mismatch; we obtain a conversion efficiency of - 32 dB in silicon nanowaveguides with a length of 5.8 mm. Such on-chip optical wavelength converters can find important potential applications in highly-integrated optical circuits for all-optical ultrafast signal processing.
入藏号: WOS:000399249100011
ISSN: 1071-2836
eISSN: 1573-8760
第 180 条,共 255 条
标题: Mid-Infrared Luminescence of Pr3+-Doped GeS2-Ga2S3-PbI2 Bulk Chalcohalide Glasses
作者: Chen, HY (Chen, Hongyan); Cui, XX (Cui, Xiaoxia); Guo, HT (Guo, Haitao); Xu, YT (Xu, Yantao); Quan, Z (Quan, Zhao); Wang, N (Wang, Ning); Peng, B (Peng, Bo)
来源出版物: SCIENCE OF ADVANCED MATERIALS 卷: 9 期: 3-4 页: 353-358 DOI: 10.1166/sam.2017.2302 出版年: MAR 2017
摘要: 0.2 wt% Pr3+-doped (100-x)(0.8GeS(2) center dot 0.2Ga(2)S(3)) center dot xPbI(2) (x = 5, 10, and 15) glasses as potential gain materials for mid-infrared fiber laser devices were prepared, and detection of absorption and mid-infrared emission spectra was conducted. similar to 4.6 mu m mid-infrared fluorescence emissions from Pr3+ in these sulfide glasses were clearly observed at room temperature excited by a 2.01 mu m Tm3+: YAG ceramic laser system, and the radiative rates of Pr3+ ions were calculated using the Judd-Ofelt theory. 68GeS(2) center dot 17Ga(2)S(3) center dot 15PbI(2) (sigma(abs2010) = 2.70 x 10(-20) cm(2), sigma(emi) (4600) = 8.13 x 10(-20) cm(2), tau(rad) = 6.14 ms) might be a potential gain material for mid-infrared fiber laser beyond 4 mu m.
入藏号: WOS:000397862500010
ISSN: 1947-2935
eISSN: 1947-2943
第 181 条,共 255 条
标题: Non-negative infrared patch-image model: Robust target-background separation via partial sum minimization of singular values
作者: Dai, YM (Dai, Yimian); Wu, YQ (Wu, Yiquan); Song, Y (Song, Yu); Guo, J (Guo, Jun)
来源出版物: INFRARED PHYSICS & TECHNOLOGY 卷: 81 页: 182-194 DOI: 10.1016/j.infrared.2017.01.009 出版年: MAR 2017
摘要: To further enhance the small targets and suppress the heavy clutters simultaneously, a robust non negative infrared patch-image model via partial sum minimization of singular values is proposed. First, the intrinsic reason behind the undesirable performance of the state-of-the-art infrared patch-image (IPI) model when facing extremely complex backgrounds is analyzed. We point out that it lies in the mismatching of IPI model's implicit assumption of a large number of observations with the reality of deficient observations of strong edges. To fix this problem, instead of the nuclear norm, we adopt the partial sum of singular values to constrain the low-rank background patch-image, which could provide a more accurate background estimation and almost eliminate all the salient residuals in the decomposed target image. In addition, considering the fact that the infrared small target is always brighter than its adjacent background, we propose an additional non-negative constraint to the sparse target patch image, which could not only wipe off more undesirable components ulteriorly but also accelerate the convergence rate. Finally, an algorithm based on inexact augmented Lagrange multiplier method is developed to solve the proposed model. A large number of experiments are conducted demonstrating that the proposed model has a significant improvement over the other nine competitive methods in terms of both clutter suppressing performance and convergence rate. (C) 2017 Elsevier B.V. All rights reserved.
入藏号: WOS:000397550700024
ISSN: 1350-4495
eISSN: 1879-0275
第 182 条,共 255 条
标题: Resonance spiking by periodic loss in the double-sided liquid cooling disk oscillator
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: LASER PHYSICS 卷: 27 期: 3 文献号: 035002 DOI: 10.1088/1555-6611/aa5c10 出版年: MAR 2017
摘要: A double-sided liquid cooling Nd: YAG disk oscillator working at a pump repetition rate of 20 Hz is demonstrated. The output energy of 376 mJ is realized, corresponding to the opticaloptical efficiency of 12.8% and the slope efficiency of 14%. The pump pulse width is 300 mu s and the laser pulse width is 260 mu s. Instead of being a damped signal, the output of laser comprises undamped spikes. A periodic intra-cavity loss was found by numerical analysis, which has a frequency component near the eigen frequency of the relaxation oscillation. Resonance effect will induce amplified spikes even though the loss fluctuates in a small range. The Shark-Hartmann sensor was used to investigate the wavefront aberration induced by turbulent flow and temperature gradient. According to the wavefront and fluid mechanics analysis, it is considered that the periodic intra-cavity loss can be attributed to turbulent flow and temperature gradient.
入藏号: WOS:000397525700001
ISSN: 1054-660X
eISSN: 1555-6611
第 183 条,共 255 条
标题: Significant improvement of gamma radiation resistance in CeO2 doped phosphate glass by co-doping with Sb2O3
作者: He, QL (He, Quanlong); Wang, PF (Wang, Pengfei); Sun, MY (Sun, Mengya); Lu, M (Lu, Min); Peng, B (Peng, Bo)
来源出版物: OPTICAL MATERIALS EXPRESS 卷: 7 期: 3 页: 1113-1121 DOI: 10.1364/OME.7.001113 出版年: MAR 1 2017
摘要: We show that the gamma radiation resistances of new type of phosphate glass can be greatly improved by CeO2 and Sb2O3 co-doping. With the doping of CeO2, the radiation resistance (transmittance decrease ratio) is improved from 57.39% to 73.9% at 525 nm, and from 56.4% to 61.9% at 385 nm, respectively, when optical glasses were exposed to the gamma radiation with the dose of 250 krad (Si). It further increases to 92.4% at 525 nm by co-doping with Sb2O3, meanwhile, the induced optical losses were distinctly restrained at 1064 nm and 1550 nm, which shows potential applications in the fields of space-born star camera systems, laser window optics, fiber gyroscopes and communications. (C) 2017 Optical Society of America
入藏号: WOS:000395672700052
ISSN: 2159-3930
第 184 条,共 255 条
标题: Comparative Study of Data Compression Methods for Large Aperture Static Imaging Spectrometer
作者: Yu, L (Yu Lu); Liu, XB (Liu Xue-bin); Li, HB (Li Hong-bo); Liu, GZ (Liu Gui-zhong)
来源出版物: SPECTROSCOPY AND SPECTRAL ANALYSIS 卷: 37 期: 3 页: 939-945 DOI: 10.3964/j.issn.1000-0593(2017)03-0939-07 出版年: MAR 2017
摘要: Facing the problem of choosing different data source as compressing object results in different compression effect, several techniques are investigated to explore a better data source which can reduce the loss of image and spectral information while getting higher compression ratio in the compression work of the large aperture static imaging spectrometer. In this paper the optical path difference dimension data source of LASIS was proposed after analyzing the characteristic of LASIS and then compared with the LASIS and LAMIS data source in detail. The SWIR data collected with the principle prototype of LASIS were used in our experiment. Firstly, three forms of data sources were extracted after detailedly introducing their data characteristic and extracting methods. Secondly, the mature algorithms in engineering JPEG and JPEG2000 were employed to compress and reconstruct the three forms of data sources respectively. Finally, the compression effect was evaluated in the aspect of image content, interference dimension, spectral dimension and compression ratio respectively, and the original spectral curves of three materials choosing from the field of view and those after reconstruction were extracted next, then the loss of spectral information of these three materials were measured by using the SA (Spectral Angle) and RQE (Relative Quadratic Error) values of the spectral curves to evaluate the compression effect. It is demonstrated that using the optical path difference dimension data as compressing object shows obvious advantages compared with LASIS and LAMIS, which achieves a combination of higher compression ratio, lower mean square error, lower peak signal noise ratio and less information loss that is competitive with the best results from the literature. The results show that the proposed optical path difference dimension data source has good performance in preserving the spatial and spectral information during the compression of LASIS than the other two common forms data sources of LASTS.
入藏号: WOS:000397352600049
ISSN: 1000-0593
第 185 条,共 255 条
标题: Visible and near-infrared optical properties of Nd:CLNGG crystal waveguides formed by proton implantation
作者: Liu, CX (Liu, Chun-Xiao); Shen, XL (Shen, Xiao-Liang); Li, WN (Li, Wei-Nan); Wei, W (Wei, Wei)
来源出版物: CHINESE PHYSICS B 卷: 26 期: 3 文献号: 034207 DOI: 10.1088/1674-1056/26/3/034207 出版年: MAR 2017
摘要: A Nd:CLNGG waveguide structure operated at wavelengths of both 632.8 nm and 1539 nm was demonstrated for the first time to our knowledge, which was produced by the 480-keV H+ ion implantation with a dose of 1.0 x 10(17) protons/cm(2). Its propagating modes at 632.8 nm and 1539 nm were measured by the well-known prism coupling technique. The refractive index profile at either 632.8-nm wavelength or 1539-nm wavelength was optical barrier type in the proton-implanted Nd:CLNGG crystal optical waveguide, which was calculated by using the reflectivity calculation method. The near-field light intensity distributions were also simulated by the finite-difference beam propagation method in the visible and near-infrared bands.
入藏号: WOS:000396129200026
ISSN: 1674-1056
eISSN: 1741-4199
第 186 条,共 255 条
标题: Penalized Linear Discriminant Analysis of Hyperspectral Imagery for Noise Removal
作者: Lu, M (Lu, Ming); Hu, LJ (Hu, Luojia); Yue, TX (Yue, Tianxiang); Chen, ZY (Chen, Ziyue); Chen, B (Chen, Bin); Lu, XQ (Lu, Xiaoqiang); Xu, B (Xu, Bing)
来源出版物: IEEE GEOSCIENCE AND REMOTE SENSING LETTERS 卷: 14 期: 3 页: 359-363 DOI: 10.1109/LGRS.2016.2643001 出版年: MAR 2017
摘要: The existence of noise in hyperspectral imagery (HSI) seriously affects image quality. Noise removal is one of the most important and challenging tasks to complete before hyperspectral information extraction. Though many advances have been made in alleviating the effect of noise, problems, including a high correlation among bands and predefined structure of noise covariance, still prevent us from the effective implementation of hyperspectral denoising. In this letter, a new algorithm named the penalized linear discriminant analysis (PLDA) and noise adjusted principal components transformation (NAPCT) was proposed. PLDA was applied to search for the best noise covariance structure, while the NAPCT was employed to remove the noise. The results of the tests with both HJ-1A HSI and EO-1 Hyperion showed that the proposed PLDA-NAPCT method could remove the noise effectively and that it could preserve the spectral fidelity of the restored hyperspectral images. Specifically, the recovered spectral curves using the proposed method are visually more similar to the original image compared with the control methods; quantitative matrices, including the noise reduction ration and mean relative deviation, also showed that the PLDA-NAPCT produced less bias than the control methods. Furthermore, the PLDA-NAPCT method is sensor-independent, and it could be easily adapted for removing the noise from different sensors.
入藏号: WOS:000395908600017
作者识别号:
作者        ResearcherID 号        ORCID 号
Lu, Xiaoqiang                  0000-0002-7037-5188
ISSN: 1545-598X
eISSN: 1558-0571
第 187 条,共 255 条
标题: Template Deformation-Based 3-D Reconstruction of Full Human Body Scans From Low-Cost Depth Cameras
作者: Liu, ZB (Liu, Zhenbao); Huang, JX (Huang, Jinxin); Bu, SH (Bu, Shuhui); Han, JW (Han, Junwei); Tang, XJ (Tang, Xiaojun); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 47 期: 3 页: 695-708 DOI: 10.1109/TCYB.2016.2524406 出版年: MAR 2017
摘要: Full human body shape scans provide valuable data for a variety of applications including anthropometric surveying, clothing design, human-factors engineering, health, and entertainment. However, the high price, large volume, and difficulty of operating professional 3-D scanners preclude their use in home entertainment. Recently, portable low-cost red green blue-depth cameras such as the Kinect have become popular for computer vision tasks. However, the infrared mechanism of this type of camera leads to noisy and incomplete depth images. We construct a stereo full-body scanning environment composed of multiple depth cameras and propose a novel registration algorithm. Our algorithm determines a segment constrained correspondence for two neighboring views, integrating them using rigid transformation. Furthermore, it aligns all of the views based on uniform error distribution. The generated 3-D mesh model is typically sparse, noisy, and even with holes, which makes it lose surface details. To address this, we introduce a geometric and topological fitting prior in the form of a professionally designed high-resolution template model. We formulate a template deformation optimization problem to fit the high-resolution model to the low-quality scan. Its solution overcomes the obstacles posed by different poses, varying body details, and surface noise. The entire process is free of body and template markers, fully automatic, and achieves satisfactory reconstruction results.
入藏号: WOS:000396395400013
ISSN: 2168-2267
eISSN: 2168-2275
第 188 条,共 255 条
标题: Passively mode-locked laser with an ultra-narrow spectral width
作者: Kues, M (Kues, Michael); Reimer, C (Reimer, Christian); Wetzel, B (Wetzel, Benjamin); Roztocki, P (Roztocki, Piotr); Little, BE (Little, Brent E.); Chu, ST (Chu, Sai T.); Hansson, T (Hansson, Tobias); Viktorov, EA (Viktorov, Evgeny A.); Moss, DJ (Moss, David J.); Morandotti, R (Morandotti, Roberto)
来源出版物: NATURE PHOTONICS 卷: 11 期: 3 页: 159-+ DOI: 10.1038/NPHOTON.2016.271 出版年: MAR 2017
摘要: Most mode-locking techniques introduced in the past(1,2) focused mainly on increasing the spectral bandwidth to achieve ultra-short, sub-picosecond-long coherent light pulses. By contrast, less importance seemed to be given to mode-locked lasers generating Fourier-transform-limited nanosecond pulses, which feature the narrow spectral bandwidths required for applications in spectroscopy(3), the efficient excitation of molecules(4), sensing and quantum optics(5). Here, we demonstrate a passively mode-locked laser system that relies on simultaneous nested cavity filtering and cavity-enhanced nonlinear interactions within an integrated microring resonator. This allows us to produce optical pulses in the nanosecond regime (4.3 ns in duration), with an overall spectral bandwidth of 104.9 MHz-more than two orders of magnitude smaller than previous realizations. The very narrow bandwidth of our laser makes it possible to fully characterize its spectral properties in the radiofrequency domain using widely available GHz-bandwidth optoelectronic components. In turn, this characterization reveals the strong coherence of the generated pulse train.
入藏号: WOS:000395663900008
作者识别号:
作者        ResearcherID 号        ORCID 号
moss, david                  0000-0001-5195-1744
CHU, Sai Tak                  0000-0001-8263-8507
ISSN: 1749-4885
eISSN: 1749-4893
第 189 条,共 255 条
标题: A new kind of vertically aligned field emission transistor with a cylindrical vacuum channel
作者: Shen, ZH (Shen, Zhihua); Wang, X (Wang, Xiao); Wu, SL (Wu, Shengli); Tian, JS (Tian, Jinshou)
来源出版物: VACUUM 卷: 137 页: 163-168 DOI: 10.1016/j.vacuum.2017.01.002 出版年: MAR 2017
摘要: This study investigated a vertically aligned field emission transistor with a cylindrical vacuum channel. The channel length of this proposed transistor can be precisely controlled and easily fabricated to be comparable to the mean free path of electrons in air so that the device can operate in the air without performance degradation. In the study, this vacuum transistor showed a low threshold voltage (1.2 V, 2.2 V, and 3.3 V) with a gate dielectric thickness of 10 nm, 15 nm, and 20 nm and a subthreshold slope of 1.1 V/dec. It was found that the vacuum channel radius should be no less than 20 nm, otherwise, severe performance degradation will appear due to the effect of the gate shield (leading to reduction of the anode current) and electron collision events with the dielectric layer (presenting reliability issues). This kind of vacuum transistor may have wide applications in extreme conditions such as high temperature and intense irradiation. (C) 2017 Elsevier Ltd. All rights reserved.
入藏号: WOS:000394070200024
ISSN: 0042-207X
第 190 条,共 255 条
标题: Femtowatt incoherent image conversion from mid-infrared light to near-infrared light
作者: Huang, N (Huang, Nan); Liu, HJ (Liu, Hongjun); Wang, ZL (Wang, Zhaolu); Han, J (Han, Jing); Zhang, S (Zhang, Shuan)
来源出版物: LASER PHYSICS 卷: 27 期: 3 页: 1-5 文献号: 035401 DOI: 10.1088/1555-6611/aa57db 出版年: MAR 2017
摘要: We report on the experimental conversion imaging of an incoherent continuous-wave dim source from mid-infrared light to near-infrared light with a lowest input power of 31 femtowatt (fW). Incoherent mid-infrared images of light emission from a heat lamp bulb with an adjustable power supply at window wavelengths ranging from 2.9 mu m to 3.5 mu m are used for upconversion. The sum-frequency generation is realized in a laser cavity with the resonant wavelength of 1064 nm pumped by an LD at 806 nm built around a periodically poled lithium niobate (PPLN) crystal. The converted infrared image in the wavelength range similar to 785 nm with a resolution of about 120 x 70 is low-noise detected using a silicon-based camera. By optimizing the system parameters, the upconversion quantum efficiency is predicted to be 28% for correctly polarized, on-axis and phase-matching light.
入藏号: WOS:000394607300001
ISSN: 1054-660X
eISSN: 1555-6611
第 191 条,共 255 条
标题: Refractive index and temperature sensitivity characterization of excessively tilted fiber grating
作者: Yan, Z (Yan, Z.); Sun, Q (Sun, Q.); Wang, C (Wang, C.); Sun, Z (Sun, Z.); Mou, C (Mou, C.); Zhou, K (Zhou, K.); Liu, D (Liu, D.); Zhang, L (Zhang, L.)
来源出版物: OPTICS EXPRESS 卷: 25 期: 4 页: 3336-3346 出版年: FEB 20 2017
摘要: We have investigated experimentally and numerically the temperature and refractive index (RI) sensitivity characteristics of excessively tilted fiber gratings (Ex-TFGs) in detail. Both results have shown that the temperature and RI sensitivities of Ex-TFGs are mode order dependent. For temperature sensitivity, the higher order cladding mode of ExT-FG exhibited lower temperature sensitivity, quantitatively, the temperature sensitivities of TM cladding modes at the resonance wavelength around 1550nm are 9pm/degrees C, 6.8pm/degrees C, 5.6pm/degrees C and, 4pm/degrees C for cladding mode 28th, 31st, 35th, 40th, respectively, indicating the overall temperature sensitivity of Ex-TFGs were lower than that of normal FBGs. The SRI sensing results have shown that the RI sensitivity of Ex-TFG at the special index value could be improved by choosing the cladding mode with effective index close to the refractive index of the detecting medium. The SRI sensitivities at the effective mode index were 2250nm/RIU at 1.408, 864nm/RIU at 1.395, 1536nm/RIU at 1.380 and 1360nm/RIU at 1.355, for the cladding mode of 28th, 31st, 35th, 43rd, respectively. The experimental results have also shown the SRI sensitivity of Ex-TFG was increasing with increasing of the resonance wavelength. (C) 2017 Optical Society of America
入藏号: WOS:000397317400044
PubMed ID: 28241548
ISSN: 1094-4087
第 192 条,共 255 条
标题: Meta-nanocavity model for dynamic super-resolution fluorescent imaging based on the plasmonic structure illumination microscopy method
作者: Cao, S (Cao, Shun); Wang, TS (Wang, Taisheng); Sun, Q (Sun, Qiang); Hu, BL (Hu, Bingliang); Yu, WX (Yu, Weixing)
来源出版物: OPTICS EXPRESS 卷: 25 期: 4 页: 3863-3874 DOI: 10.1364/OE.25.003863 出版年: FEB 20 2017
摘要: Biological research requires dynamic and wide-field optical microscopy with resolution down to nanometer to study the biological process in a sub-cell or single molecular level. To address this issue, we propose a dynamic wide-field optical nanoimaging method based on a meta-nanocavity platform (MNCP) model which can be incorporated in micro/nano-fluidic systems so that the samples to be observed can be confined in a nano-scale space for the ease of imaging. It is found that this platform can support standing wave surface plasmons (SW-SPs) interference pattern with a period of 105 nm for a 532 nm incident wavelength. Furthermore, the potential application of the NCP for wide-field super-resolution imaging was discussed and the simulation results show that an imaging resolution of sub-80 nm can be achieved. (C) 2017 Optical Society of America
入藏号: WOS:000397317400091
PubMed ID: 28241597
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: 1094-4087
第 193 条,共 255 条
标题: An improved schlieren method for measurement and automatic reconstruction of the far-field focal spot
作者: Wang, ZZ (Wang, Zhengzhou); Hu, BL (Hu, Bingliang); Yin, QY (Yin, Qinye)
来源出版物: PLOS ONE 卷: 12 期: 2 文献号: e0171415 DOI: 10.1371/journal.pone.0171415 出版年: FEB 16 2017
摘要: The schlieren method of measuring far-field focal spots offers many advantages at the Shenguang III laser facility such as low cost and automatic laser-path collimation. However, current methods of far-field focal spot measurement often suffer from low precision and efficiency when the final focal spot is merged manually, thereby reducing the accuracy of reconstruction. In this paper, we introduce an improved schlieren method to construct the high dynamic-range image of far-field focal spots and improve the reconstruction accuracy and efficiency. First, a detection method based on weak light beam sampling and magnification imaging was designed; images of the main and side lobes of the focused laser irradiance in the far field were obtained using two scientific CCD cameras. Second, using a self correlation template matching algorithm, a circle the same size as the schlieren ball was dug from the main lobe cutting image and used to change the relative region of the main lobe cutting image within a 100x100 pixel region. The position that had the largest correlation coefficient between the side lobe cutting image and the main lobe cutting image when a circle was dug was identified as the best matching point. Finally, the least squares method was used to fit the center of the side lobe schlieren small ball, and the error was less than 1 pixel. The experimental results show that this method enables the accurate, high-dynamic-range measurement of a far-field focal spot and automatic image reconstruction. Because the best matching point is obtained through image processing rather than traditional reconstruction methods based on manual splicing, this method is less sensitive to the efficiency of focal spot reconstruction and thus offers better experimental precision.
入藏号: WOS:000394424500028
PubMed ID: 28207758
ISSN: 1932-6203
第 194 条,共 255 条
标题: Superhydrophilic Antireflective Periodic Mesoporous Organosilica Coating on Flexible Polyimide Substrate with Strong Abrasion Resistance
作者: Wang, J (Wang, Jing); Zhang, C (Zhang, Cong); Yang, CM (Yang, Chunming); Zhang, C (Zhang, Ce); Wang, MC (Wang, Mengchao); Zhang, J (Zhang, Jing); Xu, Y (Xu, Yao)
来源出版物: ACS APPLIED MATERIALS & INTERFACES 卷: 9 期: 6 页: 5468-5476 DOI: 10.1021/acsami.6b14117 出版年: FEB 15 2017
摘要: Superhydrophilic antireflective periodic mesoporous organosilica (PMO) coating was prepared on flexible polyimide substrate via solvent evaporation-induced self-assembly (SEISM method, in which tetraethoxysilane (TEOS) and a special bridged silsesquioxane were used as reactants. The bridged silsesquioxane, EG-BSQ was synthesized through the stoichiometric reaction between 3-glycidoxyporpyltrimethoxysilane (GPTMS) and ethylene diamine (EDA). Under the influence of surfactant, TEOS and EG-BSQ co-condensed and enclosed the ordered mesporous in the coating. The results of grazing-incidence small-angle X-ray scattering (GISAXS) and the transmission electron microscope (TEM) indicated that the mesopores belonged to a Fmmm orthorhombic symmetry structure. With increasing EG-BSQ concentration, the mesoporous structure in the PMO coating becomes more and more disordered because silica mesopore walls shrunk or collapsed during calcination and consequently the refractive index of PMO coating became larger. The antireflective (AR) PMO coating showed an optical transmittance of 99.54% on polyimide (PI) much higher than the 88.68% of bare PI. The water contact angle of PMO coating was less than 9.0, which indicated the AR PMO coating was superhydrophilic. Moreover, the PMO coating showed an excellent mechanical property, the transmittance of the PMO coating displayed a very low loss of 0.1% after abrasion of 25 cycles by CS-10F wearaser.
入藏号: WOS:000394481800048
PubMed ID: 28107616
ISSN: 1944-8244
第 195 条,共 255 条
标题: Interface modification based ultrashort laser microwelding between SiC and fused silica
作者: Zhang, GD (Zhang, Guodong); Bai, J (Bai, Jing); Zhao, W (Zhao, Wei); Zhou, KM (Zhou, Kaiming); Cheng, GH (Cheng, Guanghua)
来源出版物: OPTICS EXPRESS 卷: 25 期: 3 页: 1702-1709 DOI: 10.1364/OE.25.001702 出版年: FEB 6 2017
摘要: It is a big challenge to weld two materials with large differences in coefficients of thermal expansion and melting points. Here we report that the welding between fused silica (softening point, 1720 degrees C) and SiC wafer (melting point, 3100 degrees C) is achieved with a near infrared femtosecond laser at 800 nm. Elements are observed to have a spatial distribution gradient within the cross section of welding line, revealing that mixing and inter-diffusion of substances have occurred during laser irradiation. This is attributed to the femtosecond laser induced local phase transition and volume expansion. Through optimizing the welding parameters, pulse energy and interval of the welding lines, a shear joining strength as high as 15.1 MPa is achieved. In addition, the influence mechanism of the laser ablation on welding quality of the sample without pre-optical contact is carefully studied by measuring the laser induced interface modification. (C) 2017 Optical Society of America
入藏号: WOS:000397314600009
ISSN: 1094-4087
第 196 条,共 255 条
标题: GROUP GENERALIZED INTERVAL-VALUED INTUITIONISTIC FUZZY SOFT SETS AND THEIR APPLICATIONS IN DECISION MAKING
作者: Wu, H (Wu, H.); Su, X (Su, X.)
来源出版物: IRANIAN JOURNAL OF FUZZY SYSTEMS 卷: 14 期: 1 页: 1-21 出版年: FEB 2017
摘要: Interval-valued intuitionistic fuzzy sets (IVIFSs) are widely used to handle uncertainty and imprecision in decision making. However, in more complicated environment, it is difficult to express the uncertain information by an IVIFS with considering the decision-making preference. Hence, this paper proposes a group generalized interval-valued intuitionistic fuzzy soft set (GGIVIFSS) which contains the basic description by interval-valued intuitionistic fuzzy soft set (IVIFSS) on the alternatives and a group of experts' evaluation of it. It contributes the following threefold: 1) A generalized interval-valued intuitionistic fuzzy soft set (GIVIFSS) is proposed by introducing an interval valued intuitionistic fuzzy parameter, which reflects a new and senior expert's opinion on the basic description. The operations, properties and aggregation operators of GIVIFSS are discussed. 2) Based on GIVIFSS, a G-GIVIFSS is then proposed to reduce the impact of decision-making preference by introducing more parameters by a group of experts. Its important operations, properties and the weighted averaging operator are also defined. 3) A multi attribute group decision making model based on G-GIVIFSS weighted averaging operator is built to solve the group decision making problems in the more universal IVIF environment, and two practical examples are taken to validate the efficiency and effectiveness of the proposed model.
入藏号: WOS:000397198200001
ISSN: 1735-0654
第 197 条,共 255 条
标题: Numerical study of the faithful replication of micro/nanostructures on curved surfaces by the electrohydrodynamic instability process
作者: Li, HF (Li, Hefu); Yu, WX (Yu, Weixing); Wang, TS (Wang, Taisheng); Liu, ZY (Liu, Zhenyu); Desmulliez, MPY (Desmulliez, M. P. Y.)
来源出版物: ELECTROPHORESIS 卷: 38 期: 3-4 页: 525-532 DOI: 10.1002/elps.201600192 出版年: FEB 2017
摘要: This paper reports the numerical study of the one-step faithful replication of micro/nanoscale structures on a fiber surface by using the electrohydrodynamic instability patterning (EHDIP) process. By employing a rigorous numerical analysis method, conditions are revealed under which the faithful replication of a pattern can be achieved from a curved master electrode. It is found that the radius of curvature of the fiber plays an important role in determining the final morphology of the pattern when the destabilizing electric field is dominant in both the flat and patterned template cases. In general, stronger electric fields and larger radii of curvature of the substrate are favorable for the faithful replication of the pattern. In addition, theoretical analysis shows that higher aspect ratio of micro/nanostructures can be obtained on curved surfaces by using a master with a much lower aspect ratio. The results demonstrated in this study aims to provide guidelines for the faithful fabrication ofmicro/nanostructures on curved surfaces by the EHDIP process.
入藏号: WOS:000396917400017
PubMed ID: 27862080
作者识别号:
作者        ResearcherID 号        ORCID 号
Yu, Weixing         G-3658-2012         0000-0002-3216-526X
Liu, Zhenyu         E-9551-2010         
Desmulliez, Marc                  0000-0002-2441-1598
ISSN: 0173-0835
eISSN: 1522-2683
第 198 条,共 255 条
标题: Real-time image haze removal using an aperture-division polarimetric camera
作者: Zhang, WF (Zhang, Wenfei); Liang, J (Liang, Jian); Ren, LY (Ren, Liyong); Ju, HJ (Ju, Haijuan); Qu, ES (Qu, Enshi); Bai, ZF (Bai, Zhaofeng); Tang, Y (Tang, Yao); Wu, ZX (Wu, Zhaoxin)
来源出版物: APPLIED OPTICS 卷: 56 期: 4 页: 942-947 DOI: 10.1364/AO.56.000942 出版年: FEB 1 2017
摘要: Polarimetric dehazing methods have been proven to be effective in enhancing the quality of images acquired in turbid media. We report a new full-Stokes polarimetric camera, which is based on the division of aperture structure. We design a kind of automatic polarimetric dehazing algorithm and load it into the field programmable gate array (FPGA) modules of our designed polarimetric camera, achieving a real-time image haze removal with an output rate of 25 fps. We demonstrate that the image quality can be significantly improved together with a good color restoration. This technique might be attractive in a range of real-time outdoor imaging applications, such as navigation, monitoring, and remote sensing. (C) 2017 Optical Society of America
入藏号: WOS:000394309200058
PubMed ID: 28158096
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 199 条,共 255 条
标题: Learning Tone Mapping Function for Dehazing
作者: Lian, XH (Lian, Xuhang); Pang, YW (Pang, Yanwei); He, YQ (He, Yuqing); Li, XL (Li, Xuelong); Yang, AP (Yang, Aiping)
来源出版物: COGNITIVE COMPUTATION 卷: 9 期: 1 页: 95-114 DOI: 10.1007/s12559-016-9437-1 出版年: FEB 2017
摘要: The existence of haze greatly degrades the image quality and hence decreases the cognition performance of a vision system. Therefore, it is crucial to remove haze from images. Instead of formulating dehazing as an image rest-oration or mathematical inversion problem, we, in this paper, conduct dehazing by learning a proper transformation function (i. e., enhancement gain) under the framework of classical image enhancement. There are three novelties. (1) It is observed that intensity-inverted hazy (foggy) image and low-light (i. e., underexposed, low-dynamic range) image are similar in the sense of properties of dark color and low-dynamic range. Based on this observation, it is straightforward to invert the intensity and then utilize low-lightoriented tone mapping in large-scale image layer to remove haze from a single hazy image. However, this simple intensity inverting plus tone mapping does not directly result in satisfying dehazing effect. (2) To make the inversion plus mapping method work, we propose an intensity smoothing algorithm consisting of maximum-based blocking and bilateral filtering, which results in remarkable dehazing result. (3) An algorithm is proposed to learn optimal tone mapping. Though our method does not rely on the imaging model of hazy image, experimental results demonstrate that our enhancement method is better than the model-based methods such as dark channel prior and its variants. The proposed method is called iItem. One key of Item is intensity inverting and the other key is learning-based tone mapping. By learning, the tone mapping is optimal in the sense of haze removal.
入藏号: WOS:000394418100007
ISSN: 1866-9956
eISSN: 1866-9964
第 200 条,共 255 条
标题: A Tunable Dispersion Waveguide Based on Graphene-Silicon Lateral Slot Geometric Structure
作者: Li, Z (Li, Zhen); Liu, HJ (Liu, Hongjun); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu); Han, J (Han, Jing)
来源出版物: IEEE PHOTONICS JOURNAL 卷: 9 期: 1 文献号: 7801109 DOI: 10.1109/JPHOT.2017.2654447 出版年: FEB 2017
摘要: The dispersion profiles of a hybrid graphene-silicon (HyGS) slot waveguide with trilayers of graphene are investigated in this paper. By tuning the bias voltage on graphene layer, the zero dispersion wavelengths (ZDW) of HyGS slot waveguide can be tailored dynamically and effectively. With small disturbed voltage (6 V), a large ZDW tuning amount (200 nm) is achieved, without the need for changing the geometric structure of the waveguide, which has been verified with numerical simulation. Moreover, the dispersion curve of HyGS slot waveguide is flat enough (group velocity dispersion slope less than 2 ps/nm(2).km), in the vicinity of ZDW. This waveguide is highly beneficial to such applications as integrated optics and graphene-related active optical devices.
入藏号: WOS:000395643200001
ISSN: 1943-0655
eISSN: 1943-0647

第 201 条,共 255 条
标题: Visible and near-infrared waveguides formed by double-energy proton implantation in magneto-optical glasses
作者: Liu, CX (Liu, Chun-Xiao); Shen, XL (Shen, Xiao-Liang); Zheng, RL (Zheng, Rui-Lin); Guo, HT (Guo, Hai-Tao); Li, WN (Li, Wei-Nan); Wei, W (Wei, Wei)
来源出版物: APPLIED PHYSICS B-LASERS AND OPTICS 卷: 123 期: 2 文献号: 56 DOI: 10.1007/s00340-017-6644-8 出版年: FEB 2017
摘要: Ion implantation is one of the most competitive methods for the fabrication of optical waveguide structures in optoelectronic materials. Tb3+-doped aluminum borosilicate glass has been demonstrated to be a type of magneto-optical glass with high Verdet constant. In this work, the proton implantation technique with energies of (500 + 550) keV and fluences of (1.0 + 2.0) x 10(16) ions/cm(2) is performed to form planar waveguides in the Tb3+-doped aluminum borosilicate glass. The guiding modes of the fabricated waveguide were measured by the prism-coupling method at wavelengths of 632.8 and 1539 nm. The near-field light intensity distribution was measured by the end-face coupling method at the wavelength of 632.8 nm and calculated by the finite-difference beam propagation method at both 632.8 and 1539 nm. The optical properties of the double-energy proton-implanted magneto-optical glass waveguides show promise for use as multi-functional integrated optical devices in the visible and near-infrared bands.
入藏号: WOS:000394290900005
ISSN: 0946-2171
eISSN: 1432-0649
第 202 条,共 255 条
标题: Learning Instance Correlation Functions for Multilabel Classification
作者: Liu, HW (Liu, Huawen); Li, XL (Li, Xuelong); Zhang, SC (Zhang, Shichao)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 47 期: 2 页: 499-510 DOI: 10.1109/TCYB.2016.2519683 出版年: FEB 2017
摘要: Multilabel learning has a wide range of potential applications in reality. It attracts a great deal of attention during the past years and has been extensively studied in many fields including image annotation and text categorization. Although many efforts have been made for multilabel learning, there are two challenging issues remaining, i.e., how to exploit the correlations and how to tackle the high-dimensional problems of multilabel data. In this paper, an effective algorithm is developed for multilabel classification with utilizing those data that are relevant to the targets. The key is the construction of a coefficient-based mapping between training and test instances, where the mapping relationship exploits the correlations among the instances, rather than the explicit relationship between the variables and the class labels of data. Further, a constraint, l(1)-norm penalty, is performed on the mapping relationship to make the model sparse, weakening the impacts of noisy data. Our empirical study on eight public datasets shows that the proposed method is more effective in comparing with the state-of-the-art multilabel classifiers.
入藏号: WOS:000395476200020
ISSN: 2168-2267
eISSN: 2168-2275
第 203 条,共 255 条
标题: Secrecy-Optimized Resource Allocation for Device-to-Device Communication Underlaying Heterogeneous Networks
作者: Zhang, KC (Zhang, Kecheng); Peng, MG (Peng, Mugen); Zhang, P (Zhang, Ping); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 卷: 66 期: 2 页: 1822-1834 DOI: 10.1109/TVT.2016.2566298 出版年: FEB 2017
摘要: Device-to-device (D2D) communications have recently attracted much attention for the potential capability to improve spectral efficiency (SE) underlaying the existing heterogeneous networks (HetNets). Due to no sophisticated control, D2D-worked user equipments (DUEs) themselves cannot resist eavesdropping or security attacks. It is urgent to maximize the secure capacity for both cellular users and DUEs. This paper formulates the radio resource-allocation problem to maximize the secure capacity of DUEs for D2D communication underlaying HetNets, which consist of high-power nodes (HPNs) and low-power nodes (LPNs). The optimization objective function with transmit bit rate and power constraints, which is nonconvex and hard to directly derive, is first transformed into a matrix form. Then, the equivalent convex form of the optimization problem is derived according to Perron-Frobenius theory. A heuristic iterative algorithm based on the proximal theory is proposed to solve this equivalent convex problem through evaluating the proximal operator of the Lagrange function. Numerical results show that the proposed radio resource-allocation solution significantly improves the secure capacity with a fast convergence speed.
入藏号: WOS:000395740300074
作者识别号:
作者        ResearcherID 号        ORCID 号
zhang, kecheng         J-6920-2017         
ISSN: 0018-9545
eISSN: 1939-9359
第 204 条,共 255 条
标题: High-efficiency supercontinuum generation in solid thin plates at 0.1 TW level
作者: He, P (He, Peng); Liu, YY (Liu, Yangyang); Zhao, K (Zhao, Kun); Teng, H (Teng, Hao); He, XK (He, Xinkui); Huang, P (Huang, Pei); Huang, HD (Huang, Hangdong); Zhong, SY (Zhong, Shiyang); Jiang, YJ (Jiang, Yujiao); Fang, SB (Fang, Shaobo); Hou, X (Hou, Xun); Wei, ZY (Wei, Zhiyi)
来源出版物: OPTICS LETTERS 卷: 42 期: 3 页: 474-477 DOI: 10.1364/OL.42.000474 出版年: FEB 1 2017
摘要: Supercontinuum generation in a solid-state medium was investigated experimentally. A continuum covering 460 to 950 nm was obtained when 0.8 mJ/30 fs Ti: sapphire laser pulses were applied to seven thin fused silica plates at a 1 kHz repetition rate. The primary processes responsible for spectral broadening were self-phase modulation (SPM) and self-steepening, while SPM and self-focusing were balanced to optimize the spectral broadening and suppress the multi-photon process. The output was compressed to a 5.4 fs and a 0.68 mJ pulse, corresponding to two optical cycles and 0.13 TW of peak power. (C) 2017 Optical Society of America
入藏号: WOS:000393307500027
PubMed ID: 28146505
ISSN: 0146-9592
eISSN: 1539-4794
第 205 条,共 255 条
标题: Synthesis and spectroscopy of high concentration dysprosium doped GeS2-Ga2S3-CdI2 chalcohalide glasses and fiber fabrication
作者: Wang, ZX (Wang, Zixuan); Guo, HT (Guo, Haitao); Xiao, XS (Xiao, Xusheng); Xu, YT (Xu, Yantao); Cui, XX (Cui, Xiaoxia); Lu, M (Lu, Min); Peng, B (Peng, Bo); Yang, AP (Yang, Anping); Yang, ZY (Yang, Zhiyong); Gu, SX (Gu, Shaoxuan)
来源出版物: JOURNAL OF ALLOYS AND COMPOUNDS 卷: 692 页: 1010-1017 DOI: 10.1016/j.jallcom.2016.09.085 出版年: JAN 25 2017
摘要: 0.2%-3% weight of Dy3+ ions doped 64GeS(2)center dot 16Ga(2)S(3)center dot 20CdI(2) glasses were synthesized, and their spectroscopic properties were investigated. It was shown that the host glass could dissolve as much as 3% Dy3+ ions without deteriorating the glass transparency. The mid-infrared (MIR) emissions of the glasses did not present remarkable concentration quenching when the Dy3+ ions concentration was less than 0.6%. It was also shown that the MIR emission properties could be significantly improved by reducing S-H/O-H impurities in the glasses. The spectral analyses indicated that the 2.9 and 4.3 mu m emissions of Dy3+ ions in the glass showed relatively large stimulated emission cross sections. The glass doped with as high as 0.4% Dy3+ ions was successfully drawn into fibers, indicating good potential of the doped glass for MIR lasers. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000386231200133
作者识别号:
作者        ResearcherID 号        ORCID 号
Yang, Zhiyong         H-1309-2013         0000-0003-1070-2498
ISSN: 0925-8388
eISSN: 1873-4669
第 206 条,共 255 条
标题: Sheared-beam imaging target reconstruction based on all-phase spectrum analysis
作者: Chen, ML (Chen Ming-Lai); Luo, XJ (Luo Xiu-Juan); Zhang, Y (Zhang Yu); Lan, FY (Lan Fu-Yang); Liu, H (Liu Hui); Cao, B (Cao Bei); Xia, AL (Xia Ai-Li)
来源出版物: ACTA PHYSICA SINICA 卷: 66 期: 2 文献号: 024203 DOI: 10.7498/aps.66.024203 出版年: JAN 20 2017
摘要: Sheared-beam imaging technique is considered to be a non-conventional speckle technique for remote imaging through turbulent medium. In this high resolution imaging technique, three beams are splitted from one laser source and illuminate a remote target simultaneously in shearing distribution. Each beam is modulated by a tiny frequency shift so that these beams can interfere and beat together. The returning speckle signals are received by an array of detectors. The primary algorithm for the signal processing and image reconstruction has been developed previously. However, the reconstructed image is deteriorated by the frequency drifting error and spectrum leakage. These frequency errors are always from the transmitter and scattered signals that are caused by spectrum-shift errors from acousticoptic modulators, atmospheric turbulence, Doppler effects of moving targets, etc. To solve the problems mentioned above, in this paper we propose a new image reconstruction algorithm based on the all-phase spectrum analysis theory. The all-phase fast Fourier transform (FFT) spectrum analysis theory, which can effectively inhibit spectral leakage and correct speckle spectrum, is used to process the scattered signals. By searching for the accurate positions of the beat frequency components in the transformed frequency domain data, the speckle amplitude and phase difference frames can be extracted accurately. Based on the speckle phase-difference frames, the phase distribution of the wavefront is derived by least-square algorithm. The phase distribution in grid is highly coherent, in which each point is related to the phases of its four nearest neighbors. If an initial phase map is given or preset, the phase map of the wavefront can be estimated accurately by Gauss-Seidel method. Meanwhile, the amplitude of wavefront is obtained by the algebraic operation of speckle amplitude frames. The reconstructed wavefront is inverse Fourier transformed to yield a two dimensional image. A series of speckled images of the same object are averaged to reduce the speckle noise. The proposed method improves the ability of system imaging in the actual imaging environment. Simulation experiments validate the effectiveness of the proposed algorithm, and simulation results show that the proposed image reconstruction algorithm can inhibit the frequency errors from influencing imaging quality when there exist frequency errors in scattered signals. Thus, the imaging quality of the algorithm based on the all-phase FFT method is much better than that of the algorithm based on the traditional FFT method. The substantial usage of this technique is widely spread after the reconstruction algorithm has been optimized.
入藏号: WOS:000397107800013
ISSN: 1000-3290
第 207 条,共 255 条
标题: Estimation of position and velocity for a low dynamic vehicle in near space using nonresolved photometric and astrometric data
作者: Jing, N (Jing, Nan); Li, C (Li, Chuang); Chong, YQ (Chong, Yaqin)
来源出版物: APPLIED OPTICS 卷: 56 期: 3 页: 671-681 DOI: 10.1364/AO.56.000671 出版年: JAN 20 2017
摘要: An estimation method for indirectly observable parameters for a typical low dynamic vehicle (LDV) is presented. The estimation method utilizes apparent magnitude, azimuth angle, and elevation angle to estimate the position and velocity of a typical LDV, such as a high altitude balloon (HAB). In order to validate the accuracy of the estimated parameters gained from an unscented Kalman filter, two sets of experiments are carried out to obtain the nonresolved photometric and astrometric data. In the experiments, a HAB launch is planned; models of the HAB dynamics and kinematics and observation models are built to use as time update and measurement update functions, respectively. When the HAB is launched, a ground-based optoelectronic detector is used to capture the object images, which are processed using aperture photometry technology to obtain the time-varying apparent magnitude of the HAB. Two sets of actual and estimated parameters are given to clearly indicate the parameter differences. Two sets of errors between the actual and estimated parameters are also given to show how the estimated position and velocity differ with respect to the observation time. The similar distribution curve results from the two scenarios, which agree within 3s, verify that nonresolved photometric and astrometric data can be used to estimate the indirectly observable state parameters (position and velocity) for a typical LDV. This technique can be applied to small and dim space objects in the future. (C) 2017 Optical Society of America
入藏号: WOS:000393347900074
PubMed ID: 28157929
ISSN: 1559-128X
eISSN: 2155-3165
第 208 条,共 255 条
标题: Short-term prediction of UT1-UTC by combination of the grey model and neural networks
作者: Lei, Y (Lei, Yu); Guo, M (Guo, Min); Hu, DD (Hu, Dan-dan); Cai, HB (Cai, Hong-bing); Zhao, DN (Zhao, Dan-ning); Hu, ZP (Hu, Zhao-peng); Gao, YP (Gao, Yu-ping)
来源出版物: ADVANCES IN SPACE RESEARCH 卷: 59 期: 2 页: 524-531 DOI: 10.1016/j.asr.2016.10.030 出版年: JAN 15 2017
摘要: UT1-UTC predictions especially short-term predictions are essential in various fields linked to reference systems such as space navigation and precise orbit determinations of artificial Earth satellites. In this paper, an integrated model combining the grey model GM (1, 1) and neural networks (NN) are proposed for predicting UT1-UTC. In this approach, the effects of the Solid Earth tides and ocean tides together with leap seconds are first removed from observed UT1-UTC data to derive UT1R-TAI. Next the derived UT1R-TAI time-series are de-trended using the GM(1, 1) and then residuals are obtained. Then the residuals are used to train a network. The subsequently predicted residuals are added to the GM(1, 1) to obtain the UT1R-TAI predictions. Finally, the predicted UT1R-TAI are corrected for the tides together with leap seconds to obtain UT1-UTC predictions. The daily values of UT1-UTC between January 7, 2010 and August 6, 2016 from the International Earth Rotation and Reference Systems Service (IERS) 08 C04 series are used for modeling and validation of the proposed model. The results of the predictions up to 30 days in the future are analyzed and compared with those by the GM(1, 1)-only model and combination of the least-squares (LS) extrapolation of the harmonic model including the linear part, annual and semi-annual oscillations and NN. It is found that the proposed model outperforms the other two solutions. In addition, the predictions are compared with those from the Earth Orientation Parameters Prediction Comparison Campaign (EOP PCC) lasting from October 1, 2005 to February 28, 2008. The results show that the prediction accuracy is inferior to that of those methods taking into account atmospheric angular momentum (AAM), i.e., Kalman filter and adaptive transform from AAM to LODR, but noticeably better that of the other existing methods and techniques, e.g., autoregressive filtering and least-squares collocation. (C) 2016 COSPAR. Published by Elsevier Ltd. All rights reserved.
入藏号: WOS:000392773700003
ISSN: 0273-1177
eISSN: 1879-1948
第 209 条,共 255 条
标题: Small-period long-period fiber grating with improved refractive index sensitivity and dual-parameter sensing ability
作者: Shen, FC (Shen, Fangcheng); Wang, CL (Wang, Changle); Sun, ZY (Sun, Zhongyuan); Zhou, KM (Zhou, Kaiming); Zhang, L (Zhang, Lin); Shu, XW (Shu, Xuewen)
来源出版物: OPTICS LETTERS 卷: 42 期: 2 页: 199-202 DOI: 10.1364/OL.42.000199 出版年: JAN 15 2017
摘要: We UV inscribe and characterize a long-period fiber grating with a period of 25 mu m. A series of polarization-dependent dual-peak pairs can be seen in the transmission spectrum, even though only the symmetrical refractive index modification is introduced. The fabricated grating exhibits a lower temperature sensitivity compared with standard long-period gratings and an enhanced refractive index sensitivity of similar to 312.5 nm/RIU averaged from 1.315 to 1.395, which is more than four-fold higher than standard long-period gratings in this range. The full width at half-maximum of the fabricated grating is only about 0.6 nm, allowing for high-resolution sensing. Moreover, the grating period is so small that the attenuation dip corresponding to a high-order Bragg resonance can also be seen, which can act as a monitor of the unwanted perturbation to realize dual-parameter sensing. (C) 2017 Optical Society of America
入藏号: WOS:000392193100007
PubMed ID: 28081071
作者识别号:
作者        ResearcherID 号        ORCID 号
Zhou, Kaiming         E-5903-2011         0000-0002-6011-1912
ISSN: 0146-9592
eISSN: 1539-4794
第 210 条,共 255 条
标题: Simple and fast spectral domain algorithm for quantitative phase imaging of living cells with digital holographic microscopy
作者: Min, JW (Min, Junwei); Yao, BL (Yao, Baoli); Ketelhut, S (Ketelhut, Steffi); Engwer, C (Engwer, Christian); Greve, B (Greve, Burkhard); Kemper, B (Kemper, Bjoern)
来源出版物: OPTICS LETTERS 卷: 42 期: 2 页: 227-230 DOI: 10.1364/OL.42.000227 出版年: JAN 15 2017
摘要: We present a simple and fast phase aberration compensation method in digital holographic microscopy (DHM) for quantitative phase imaging of living cells. By analyzing the frequency spectrum of an off-axis hologram, phase aberrations can be compensated for automatically without fitting or pre-knowledge of the setup and/or the object. Simple and effective computation makes the method suitable for quantitative online monitoring with highly variable DHM systems. Results from automated quantitative phase imaging of living NIH-3T3 mouse fibroblasts demonstrate the effectiveness and the feasibility of the method. (C) 2017 Optical Society of America
入藏号: WOS:000392193100014
PubMed ID: 28081079
ISSN: 0146-9592
eISSN: 1539-4794
第 211 条,共 255 条
标题: Watt-level high-power passively Q-switched laser based on a black phosphorus solution saturable absorber
作者: Wang, X (Wang, Xi); Wang, ZF (Wang, Zhenfu); Wang, YG (Wang, Yonggang); Li, L (Li, Lu); Yang, GW (Yang, Guowen); Li, JP (Li, Jinping)
来源出版物: CHINESE OPTICS LETTERS 卷: 15 期: 1 文献号: 011402 DOI: 10.3788/COL201715.011402 出版年: JAN 10 2017
摘要: A novel black phosphorus (BP) solution saturable absorber (SA) is fabricated by the liquid-phase-exfoliated method and successfully used for passively Q-switched (QS) Nd:YVO4 laser. Compared with a traditional solid SA, a BP solution SA possesses more excellent optical transparency and higher damage resistance. The shortest pulse duration and highest average output power are measured to be 119 ns and 1.23 W, respectively. To the best of our knowledge, both of them are the best results among QS solid-state lasers with BP-based absorbers so far. The repetition rate is in the range of 533.2 to 722 kHz. The results indicate the potential application of the BP solution SA into high-power solid-state pulse lasers.
入藏号: WOS:000392403300017
ISSN: 1671-7694
第 212 条,共 255 条
标题: Observation of particle manipulation with axial plane optical microscopy
作者: An, S (An Sha); Peng, T (Peng Tong); Zhou, X (Zhou Xing); Han, GX (Han Guo-Xia); Huang, ZX (Huang Zhang-Xiang); Yu, XH (Yu Xiang-Hua); Cai, YN (Cai Ya-Nan); Yao, BL (Yao Bao-Li); Zhang, P (Zhang Peng)
来源出版物: ACTA PHYSICA SINICA 卷: 66 期: 1 文献号: 010702 DOI: 10.7498/aps.66.010702 出版年: JAN 5 2017
摘要: Optical micromanipulation of particles based on the optical trapping effect induced by the interaction between light and particles has been successfully applied to many interdisciplinary fields including biomedicine and material sciences. When particles are trapped in three dimensions, the conventional wide-field optical microscopy can only monitor the movement of the trapped particles in a certain transverse plane. The ability to observe the particle movement along light trajectories is limited. Recently, a novel method named axial plane optical microscopy (APOM) has been developed to directly image the axial plane that is parallel to the optical axis of an objective lens. The APOM observes the axial plane by converting the axial information of a sample into that of a transverse plane by using a 45 degrees-tilted mirror. In this paper, we propose and demonstrate that the APOM serves as an effective tool for observing the axial movement of particles in optical tweezers. By combining with a conventional wide-field optical microscopy, we show that both transverse and axial information can be acquired simultaneously for the optical micromanipulation. As in our first experimental demonstration, we observe two particles which are trapped and aligned along the optical axis. From the transverse image, only one particle is observable, and it is difficult to obtain the information along the axial direction. However, in the axial plane imaging, the longitudinal dipolar structure formed by the two particles is clearly visible. This clearly demonstrates the APOM imaging capability along the axial axis. The numerically simulations on the trapping focal spot against the position of a collimating lens agree well with our experimental APOM results. Furthermore, we directly observe the dynamic capture process of a single trapped particle in transverse plane by conventional wide-field optical microscopy as well in axial plane by the APOM, and can obtain the 3D information rapidly and simultaneously. We point out that the observable axial dynamic range is about 30 mu m. Taking advantages of no requirement of scanning and data reconstruction, the APOM has potential applications in many fields, including optical trapping with novel beams and 3D imaging of thick biological specimens.
入藏号: WOS:000397085000004
ISSN: 1000-3290
第 213 条,共 255 条
标题: Nonlinear Saturable and Polarization-induced Absorption of Rhenium Disulfide
作者: Cui, YD (Cui, Yudong); Lu, FF (Lu, Feifei); Liu, XM (Liu, Xueming)
来源出版物: SCIENTIFIC REPORTS 卷: 7 文献号: 40080 DOI: 10.1038/srep40080 出版年: JAN 5 2017
摘要: Monolayer of transition metal dichalcogenides (TMDs), with lamellar structure as that of graphene, has attracted significant attentions in optoelectronics and photonics. Here, we focus on the optical absorption response of a new member TMDs, rhenium disulphide (ReS2) whose monolayer and bulk forms have the nearly identical band structures. The nonlinear saturable and polarization-induced absorption of ReS2 are investigated at near-infrared communication band beyond its bandgap. It is found that the ReS2-covered D-shaped fiber (RDF) displays the remarkable polarization-induced absorption, which indicates the different responses for transverse electric (TE) and transverse magnetic (TM) polarizations relative to ReS2 plane. Nonlinear saturable absorption of RDF exhibits the similar saturable fluence of several tens of mu J/cm(2) and modulation depth of about 1% for ultrafast pulses with two orthogonal polarizations. RDF is utilized as a saturable absorber to achieve self-started mode-locking operation in an Er-doped fiber laser. The results broaden the operation wavelength of ReS2 from visible light to around 1550 nm, and numerous applications may benefit from the anisotropic and nonlinear absorption characteristics of ReS2, such as in-line optical polarizers, high-power pulsed lasers, and optical communication system.
入藏号: WOS:000391258300001
PubMed ID: 28053313
ISSN: 2045-2322
第 214 条,共 255 条
标题: Adaptive synchronization of delayed reaction-diffusion neural networks with unknown non-identical time-varying coupling strengths
作者: Li, JM (Li, Junmin); He, C (He, Chao); Zhang, WY (Zhang, Weiyuan); Chen, ML (Chen, Minglai)
来源出版物: NEUROCOMPUTING 卷: 219 页: 144-153 DOI: 10.1016/j.neucom.2016.09.006 出版年: JAN 5 2017
摘要: This paper concerns the asymptotic synchronization of delayed reaction-diffusion neural networks (RDNNs) with unknown nonidentical time-varying coupling strengths, where the time-varying coupling strengths are consist of continuous time-varying periodic parameters and time-invariant nonnegative parameters. By utilizing a novel adaptive approach, the differential-difference type adaptive laws of coupling strengths and adaptive controller are designed such that the nonidentical RDNNs are asymptotic synchronization. The sufficient conditions dependent on the reaction-diffusion terms are derived by constructing a novel Lyapunov-Krasovskii-like composite energy functional (CEF) and using Barbalat's lemma. Finally, a simulation example is provided to illustrate the effectiveness of the developed approach. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000390734300014
ISSN: 0925-2312
eISSN: 1872-8286
第 215 条,共 255 条
标题: Learning deep event models for crowd anomaly detection
作者: Feng, YC (Feng, Yachuang); Yuan, Y (Yuan, Yuan); Lu, XQ (Lu, Xiaoqiang)
来源出版物: NEUROCOMPUTING 卷: 219 页: 548-556 DOI: 10.1016/j.neucom.2016.09.063 出版年: JAN 5 2017
摘要: Abnormal event detection in video surveillance is extremely important, especially for crowded scenes. In recent years, many algorithms have been proposed based on hand-crafted features. However, it still remains challenging to decide which kind of feature is suitable for a specific situation. In addition, it is hard and time-consuming to design an effective descriptor. In this paper, video events are automatically represented and modeled in unsupervised fashions. Specifically, appearance and motion features are simultaneously extracted using a PCANet from 3D gradients. In order to model event patterns, a deep Gaussian mixture model (GMM) is constructed with observed normal events. The deep GMM is a scalable deep generative model which stacks multiple GMM-layers on top of each other. As a result, the proposed method acquires competitive performance with relatively few parameters. In the testing phase, the likelihood is calculated to judge whether a video event is abnormal or not. In this paper, the proposed method is verified on two publicly available datasets and compared with state-of-the-art algorithms. Experimental results show that the deep model is effective for abnormal event detection in video surveillance.
入藏号: WOS:000390734300050
ISSN: 0925-2312
eISSN: 1872-8286
第 216 条,共 255 条
标题: A novel strategy to prepare 2D g-C3N4 nanosheets and their photoelectrochemical properties
作者: Miao, H (Miao, Hui); Zhang, GW (Zhang, Guowei); Hu, XY (Hu, Xiaoyun); Mu, JL (Mu, Jianglong); Han, TX (Han, Tongxin); Fan, J (Fan, Jun); Zhu, CJ (Zhu, Changjun); Song, LX (Song, Lixun); Bai, JT (Bai, Jintao); Hou, X (Hou, Xun)
来源出版物: JOURNAL OF ALLOYS AND COMPOUNDS 卷: 690 页: 669-676 DOI: 10.1016/j.jallcom.2016.08.184 出版年: JAN 5 2017
摘要: Herein; 2D g-C3N4 nanosheets was successfully prepared by two processes: acid treatment and liquid exfoliation. The thickness of the nanosheets was nearly 4.545 nm containing similar to 13 C-N layers. The acid treatment process before liquid exfoliation for bulk g-C3N4 could effectively destroy the in-plane periodicity of the aromatic systems and made the bulk easily exfoliated. This work carefully discussed the acid treatment effect for bulk by XRD patterns, nitrogen adsorption-desorption isotherm, FT-IR spectra, and UV-vis-NIR absorption spectra. Moreover, the nanosheets was fabricated and transferred onto FTO substrates by vacuum filtration self-assembled method to carefully investigate their optical, electrical, and photoelectrochemical properties. The thin film filtrated by 2 ml g-C3N4 nanosheets supernatant showed the best photocurrent response nearly 0.5 mu A/cm(2) and the lowest resistance of charge transfer (Rct) at the interface between FTO and electrolyte. The photocurrent response could be further effectively improved from nearly 0.5 to 1.8 mu A/cm(2) by the integration of CNTs to promote charge separation and transfer. Thus, the easy, safe, and indirect synthesis of 2D g-C3N4-based nanosheets thin films opens new possibilities for the fabrication of many energy-related devices. (C) 2016 Elsevier B.V. All rights reserved.
入藏号: WOS:000385901300089
作者识别号:
作者        ResearcherID 号        ORCID 号
Fan, Jun         I-9469-2017         
ISSN: 0925-8388
eISSN: 1873-4669
第 217 条,共 255 条
标题: Modeling and control of Takagi-Sugeno fuzzy hyperbolic model for a class of nonlinear systems
作者: Li, JM (Li, Junmin); Wang, JX (Wang, Jiaxian); Chen, ML (Chen, Minglai)
来源出版物: JOURNAL OF INTELLIGENT & FUZZY SYSTEMS 卷: 33 期: 6 页: 3265-3273 DOI: 10.3233/JIFS-161780 出版年: 2017
摘要: In this paper, a Takagi-Sugeno (T-S) fuzzy hyperbolic model is proposed for the fuzzy control of a class of nonlinear systems. The consequence of the proposed model is a hyperbolic tangent dynamic model, and it is employed to represent the nonlinear system. By constructing a new Lyapunov function, the stability conditions of the open-loop T-S fuzzy hyperbolic system are derived via linear matrix inequalities (LMIs). Then, the parallel distributed compensation (PDC) method is used to design a fuzzy hyperbolic controller, and the asymptotic stability conditions of the closed-loop system are formulated via LMIs. The main advantage of the control based on T-S fuzzy hyperbolic model is that it can achieve small control amplitude via "soft" constraint control approach. Finally, the effectiveness and advantage of the proposed schemes are illustrated by a mathematical constructive example and the Van de Vusse example.
入藏号: WOS:000416842100010
ISSN: 1064-1246
eISSN: 1875-8967
第 218 条,共 255 条
标题: Development of 2.5 THz suspended porous microstructured fiber based on cyclic-olefin copolymer
作者: Chen, Q (Chen, Qi); Zhu, WJ (Zhu, Wenjing); Kong, DP (Kong, Depeng); He, XY (He, Xiaoyang); Li, B (Li, Bo); Miao, J (Miao, Jing); Luo, ZF (Luo, Zhenfei); Zhou, X (Zhou, Xun); Yang, C (Yang, Chun); Zhang, J (Zhang, Jian)
来源出版物: OPTIK 卷: 145 页: 56-60 DOI: 10.1016/j.ijleo.2017.06.124 出版年: 2017
摘要: Efficient transmission of terahertz (THz) wave is very important in the development of THz technology. Polymer microstructured fiber is ideal in THz waveguide transmission for its advantages of low loss, low dispersion and good flexibility to bend. Based on the full vector finite element method, a suspended porous microstructured fiber with the operating frequency of 2.5 THz was designed. Fiber samples made of cyclic - olefin copolymer were fabricated, and their transmission performances were measured by using the CO2 pump laser THz source. The measured minimum loss is 0.17 dB/cm and average loss is about 0.5 dB/cm. The fluctuation of transmission loss is less than 5% when the fiber is bent from 0 to 90, showing good flexibility of bending. The measured mode field distributions of the output tips show that the THz wave propagates with fundamental mode, and the energy is well confined in the core of the fiber. (C) 2017 Elsevier GmbH. All rights reserved.
入藏号: WOS:000411301600010
ISSN: 0030-4026
第 219 条,共 255 条
标题: Algorithm of focal spot reconstruction for laser measurement using the schlieren method
作者: Lin, H (Lin, Hui); Da, ZS (Da, Zheng-shang); Cao, SK (Cao, Shi-kang); Wang, ZZ (Wang, Zheng-zhou)
来源出版物: OPTIK 卷: 145 页: 61-65 DOI: 10.1016/j.ijleo.2017.07.033 出版年: 2017
摘要: The far-field distribution of lasers is an important parameter for measuring beam quality. To overcome the insufficiencies of the CCD Camera dynamic range when measuring the far field focal spot, the schlieren method was used to measure the focal spot far-field spatial distribution. Focal spot reconstruction was achieved after gray image matching, calculating the center, and image merging of the main lobe and side lobe. In this study, we used an algorithm based on the optimal arc to obtain the center for the side lobe images by fitting the circle center to improve the accuracy of the focal spot reconstruction. The results showed that the schlieren method of measuring the focal spot reconstruction algorithm could effectively, accurately and completely obtain the far-field focal spot. (C) 2017 Elsevier GmbH. All rights reserved.
入藏号: WOS:000411301600011
ISSN: 0030-4026
第 220 条,共 255 条
标题: Research on position error of sparse optical system
作者: Wang, CC (Wang, Chenchen); Shen, Y (Shen, Yang); Zou, GY (Zou, Gangyi); Li, RC (Li, Ruichang); Fan, XW (Fan, Xuewu)
来源出版物: OPTIK 卷: 144 页: 191-198 DOI: 10.1016/j.ijleo.2017.06.082 出版年: 2017
摘要: The main method to improve the resolution of optical system is to increase the aperture of the optical system, and it is a common method to use the sparse-aperture mirrors to obtain a large aperture primary mirror. The primary mirror of optical system is deployed when it is launched into the orbit, and the deviation between deployed position and design position determines the quality of the optical system. So it is necessary to analyze the position accuracy of segmented mirrors. Sparse-aperture optical system is modeled by optical software Zemax, and by adjusting six degrees of freedom of segmented mirrors can get curves between position error and image quality. The results show that different positions of segmented mirrors can produce different wave-front when they have same position error. Moving along the Z axis, the inner mirrors influence most while the outer ones influence smallest; tilt along the X axis, middle ones have maximum wave-front aberration while the outer ones produce minimum wave-front aberration. When tilt along Y axis, middle segmented mirrors have the smallest wave-front aberration and outer ones have maximum. Two methods are used to distribute the wave-front aberration onto each segmented mirror. One is that according to the relationship curves, distribute the position error to each segmented mirror alone. Another is that each one has same position errors. The final result shows that the former method has a more relax position error when generates the same wave-front aberration. (C) 2017 Elsevier GmbH. All rights reserved.
入藏号: WOS:000409150900025
ISSN: 0030-4026
第 221 条,共 255 条
标题: Design and Test of Portable Hyperspectral Imaging Spectrometer
作者: Zou, CB (Zou, Chunbo); Yang, JF (Yang, Jianfeng); Wu, DS (Wu, Dengshan); Zhao, Q (Zhao, Qiang); Gan, YQ (Gan, Yuquan); Fu, D (Fu, Di); Yang, FC (Yang, Fanchao); Liu, H (Liu, Hong); Bai, QL (Bai, Qinglan); Hu, BL (Hu, Bingliang)
来源出版物: JOURNAL OF SENSORS 文献号: 7692491 DOI: 10.1155/2017/7692491 出版年: 2017
摘要: We design and implement a portable hyperspectral imaging spectrometer, which has high spectral resolution, high spatial resolution, small volume, and lowweight. The flight test has been conducted, and the hyperspectral images are acquired successfully. To achieve high performance, small volume, and regular appearance, an improved Dyson structure is designed and used in the hyperspectral imaging spectrometer. The hyperspectral imaging spectrometer is suitable for the small platform such as CubeSat and UAV (unmanned aerial vehicle), and it is also convenient to use for hyperspectral imaging acquiring in the laboratory and the field.
入藏号: WOS:000410321900001
ISSN: 1687-725X
eISSN: 1687-7268
第 222 条,共 255 条
标题: Ablation resistance of carbides-coated C/C composites
作者: Li, HJ (Li, Hejun); Wang, YJ (Wang, Yongjie); Fu, QG (Fu, Qiangang)
来源出版物: SURFACE ENGINEERING 卷: 33 期: 11 页: 803-809 DOI: 10.1080/02670844.2017.1319899 出版年: 2017
摘要: To improve the ablation resistance of C/C composites under oxyacetylene flame, SiC, TaC and HfC coatings were fabricated on composites surface. Ablation properties of coatings were detected and the ablation mechanism was discussed in the paper as well. The centre region of SiC and TaC coatings has failed during ablation and exhibited high ablative rates; it attributed to so high ablation temperature, which was much higher melting point of their oxides (Ta2O5 and SiO2). HfC coating exhibited lowest ablative rates. The reason is that the ablation temperature was just between sinter point and melting temperature of HfO2, the oxides could behave as the thermal barrier coating during ablation and provide efficient protection for C/C composites. It can be indicated that the carbide coating provides best ablation protection between the Tammann temperature and melting point of their oxides.
入藏号: WOS:000407606800001
ISSN: 0267-0844
eISSN: 1743-2944
第 223 条,共 255 条
标题: High energy mode-locked Yb-doped fiber laser with Bi2Te3 deposited on tapered-fiber
作者: Li, L (Li, Lu); Wang, YG (Wang, Yonggang); Wang, X (Wang, Xi); Lin, T (Lin, Tao); Sun, H (Sun, Hang)
来源出版物: OPTIK 卷: 142 页: 470-474 DOI: 10.1016/j.ijleo.2017.06.029 出版年: 2017
摘要: The report presents the high energy mode-locking operation in an all-normal-dispersion Yb-doped mode-locked fiber laser based on evanescent field interaction with tapered fiber deposited with Bi2Te3 topological insulator. Different from most of solution processing methods, Bi2Te3 film is deposited on the tapered fiber by pulsed laser deposition (PLD) technology. In this way, it can bring less non-saturable losses and contact to the fiber better. By incorporating this novel fiber-taper Bi2Te3 saturable absorber into Yb-doped fiber laser cavity, a.repetition rate of 6.2 MHz mode-locked fiber laser is achieved. The maximum single pulse energy of 2 nJ is obtained. The results indicate that fiber-taper Bi2Te3 saturable absorber possesses potentiality for high power mode-locked fiber laser applications. (C) 2017 Elsevier GmbH. All rights reserved.
入藏号: WOS:000405975100059
ISSN: 0030-4026
第 224 条,共 255 条
标题: Survey of Spatio-Temporal Interest Point Detection Algorithms in Video
作者: Li, YS (Li, Yanshan); Xia, RJ (Xia, Rongjie); Huang, QH (Huang, Qinghua); Xie, WX (Xie, Weixin); Li, XL (Li, Xuelong)
来源出版物: IEEE ACCESS 卷: 5 页: 10323-10331 DOI: 10.1109/ACCESS.2017.2712789 出版年: 2017
摘要: Recently, increasing attention has been paid to the detection of spatio-temporal interest points (STIPs), which has become a key technique and research focus in the field of computer vision. Its applications include human action recognition, video surveillance, video summarization, and content based video retrieval. Amount of work has been done by many researchers in STIP detection. This paper presents a comprehensive review on STIP detection algorithms. We first propose the detailed introductions and analysis of the existing STIP detection algorithms. STIP detection algorithms are robust in detecting interest points for video in the spatio-temporal domain Next, we summarize the existing challenges in the STIP detection for video, such as low time efficiency, poor robustness with respect to camera movement, illumination change, perspective occlusion, and background clutter. This paper also presents the application situations of STIP and discusses the potential development trends of STIP detection.
入藏号: WOS:000404360000027
ISSN: 2169-3536
第 225 条,共 255 条
标题: Multi-parameter calibration of streak/framing camera based on integrated optical system with delay and attenuation modules
作者: Wu, BJ (Wu, Bingjing); He, JH (He, Junhua); Qi, WB (Qi, Wenbo); Yuan, Z (Yuan, Zheng)
来源出版物: OPTIK 卷: 138 页: 390-397 DOI: 10.1016/j.ijleo.2017.03.049 出版年: 2017
摘要: We demonstrate a multi-parameter calibration method of the streak camera and the framing camera with the help of beam division delay and attenuation devices in an integrated optical system based on sub-picosecond short-pulse UV laser. In the designed optical scheme, the four operating modes employed the optical delay, beam division delay and attenuation, and etalon modules can be switched to synchronize the UV laser pulse with the trigger signal of diagnosis instruments, calibrate the temporal resolution and dynamic range of framing cameras, and correct the sweep speed of streak cameras, respectively. The results show that the delay time error of +/-0.1 ns in the optical delay module, the uniform distribution of sub-beams with the delay time precision of +/-0.03 ps and isocon descending energy in the beam division delay and attenuation modules, and pulse broadening of similar to 22% in the whole system are achieved. In the meantime, the experiment results display the sweep speed of 1.2 ps/pixel in a streak camera and the dynamic range of 131 in a framing camera. The proposed folding optical system with high-precision, low-loss and multi-function can be extensively applied in the temporal calibration of diagnosis instruments such as streak cameras and framing cameras. (C) 2017 Elsevier GmbH. All rights reserved.
入藏号: WOS:000403516600049
ISSN: 0030-4026
第 226 条,共 255 条
标题: Discovering Diverse Subset for Unsupervised Hyperspectral Band Selection
作者: Yuan, Y (Yuan, Yuan); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 26 期: 1 页: 51-64 DOI: 10.1109/TIP.2016.2617462 出版年: JAN 2017
摘要: Band selection, as a special case of the feature selection problem, tries to remove redundant bands and select a few important bands to represent the whole image cube. This has attracted much attention, since the selected bands provide discriminative information for further applications and reduce the computational burden. Though hyperspectral band selection has gained rapid development in recent years, it is still a challenging task because of the following requirements: 1) an effective model can capture the underlying relations between different high-dimensional spectral bands; 2) a fast and robust measure function can adapt to general hyperspectral tasks; and 3) an efficient search strategy can find the desired selected bands in reasonable computational time. To satisfy these requirements, a multigraph determinantal point process (MDPP) model is proposed to capture the full structure between different bands and efficiently find the optimal band subset in extensive hyperspectral applications. There are three main contributions: 1) graphical model is naturally transferred to address band selection problem by the proposed MDPP; 2) multiple graphs are designed to capture the intrinsic relationships between hyperspectral bands; and 3) mixture DPP is proposed to model the multiple dependencies in the proposed multiple graphs, and offers an efficient search strategy to select the optimal bands. To verify the superiority of the proposed method, experiments have been conducted on three hyperspectral applications, such as hyperspectral classification, anomaly detection, and target detection. The reliability of the proposed method in generic hyperspectral tasks is experimentally proved on four real-world hyperspectral data sets.
入藏号: WOS:000402822500004
PubMed ID: 28113180
作者识别号:
作者        ResearcherID 号        ORCID 号
Lu, Xiaoqiang                  0000-0002-7037-5188
ISSN: 1057-7149
eISSN: 1941-0042
第 227 条,共 255 条
标题: Research on segmented mirror position error of optical system based on ZEMAX
作者: Wang, CC (Wang, Chenchen); Zou, GY (Zou, Gangyi); Li, RC (Li, Ruichang); Cui, J (Cui, Jian); Fan, XW (Fan, Xuewu)
来源出版物: OPTIK 卷: 137 页: 79-84 DOI: 10.1016/j.ijleo.2017.02.082 出版年: 2017
摘要: We have modeled a segmented mirror optical system by software ZEMAX, and analyzed influence of segmented mirror's position error to the optical system imaging for the first time to author's best knowledge. The primary mirror is composed of 18 segmented mirrors. By adjusting each one's position error of six freedoms, we get six relationship curves between position error and the optical system's image quality. The relationship curves show that some have different wave-front error RMS values when segmented mirrors have same position errors. The middle mirrors are sensitive to the movement along X axis direction, and the outer ones are sensitive to the movement along Y axis direction. The middle ones and outer ones are all sensitive to the tilt error, especially tilt along X, Y axis. (C) 2017 Elsevier GmbH. All rights reserved.
入藏号: WOS:000401399900011
ISSN: 0030-4026
第 228 条,共 255 条
标题: All-fiber dissipative soliton laser based on single-walled carbon nanotube absorber in normal dispersion regime
作者: Duan, LN (Duan, L. N.); Li, L (Li, L.); Wang, YG (Wang, Y. G.); Wang, X (Wang, X.)
来源出版物: OPTIK 卷: 137 页: 308-312 DOI: 10.1016/j.ijleo.2017.03.028 出版年: 2017
摘要: We demonstrat a compact Yb-doped fiber (YDF) laser based on the single-walled carbon nanotube (SWCNT) wall-paper absorber. It can operate at dissipative solitons mode-locking state stably for more than 24 h at the room temperature, and there is no significant degradation of the laser spectra, pulse train, and output power. The spectral bandwidth of the mode-locked pulses varies from 035 to 0.64 nm depending on the level of the pump power. The amplified pulses possess single pulse energy of 3.87 nJ and pulse duration of 421.9 ps. The repetition rate is similar to 23.83 MHz. The largest output power reaches 92.3 mW. (C) 2017 Elsevier GmbH. All rights reserved.
入藏号: WOS:000401399900038
ISSN: 0030-4026
第 229 条,共 255 条
标题: A Novel Segmentation Approach Combining Region- and Edge-Based Information for Ultrasound Images
作者: Luo, YZ (Luo, Yaozhong); Liu, LZ (Liu, Longzhong); Huang, QH (Huang, Qinghua); Li, XL (Li, Xuelong)
来源出版物: BIOMED RESEARCH INTERNATIONAL 文献号: 9157341 DOI: 10.1155/2017/9157341 出版年: 2017
摘要: Ultrasound imaging has become one of the most popular medical imaging modalities with numerous diagnostic applications. However, ultrasound (US) image segmentation, which is the essential process for further analysis, is a challenging task due to the poor image quality. In this paper, we propose a new segmentation scheme to combine both region- and edge-based information into the robust graph-based (RGB) segmentation method. The only interaction required is to select two diagonal points to determine a region of interest (ROI) on the original image. The ROI image is smoothed by a bilateral filter and then contrast-enhanced by histogram equalization. Then, the enhanced image is filtered by pyramid mean shift to improve homogeneity. With the optimization of particle swarm optimization (PSO) algorithm, the RGB segmentation method is performed to segment the filtered image. The segmentation results of our method have been compared with the corresponding results obtained by three existing approaches, and four metrics have been used to measure the segmentation performance. The experimental results show that the method achieves the best overall performance and gets the lowest ARE (10.77%), the second highest TPVF (85.34%), and the second lowest FPVF (4.48%).
入藏号: WOS:000400407100001
ISSN: 2314-6133
eISSN: 2314-6141
第 230 条,共 255 条
标题: A Single-Longitudinal-Mode Passively Q-Switched Nd:YVO4 Laser Using Black Phosphorus Saturable Absorber
作者: Sun, Z (Sun, Zhe); Cheng, GH (Cheng, Guang-Hua); Liu, H (Liu, Huan); Wang, X (Wang, Xi); Wang, YG (Wang, Yong-Gang)
来源出版物: CHINESE PHYSICS LETTERS 卷: 34 期: 1 文献号: 014204 DOI: 10.1088/0256-307X/34/1/014204 出版年: JAN 2017
摘要: A black phosphorus (BP) saturable absorber (SA) solution with different concentrations (1.0 and 0.5 mg/ml) is fabricated with the liquid-phase exfoliation method. By using the BP-SA, a compact diode-pumped passively Q-switched Nd:YVO4 laser is demonstrated. One reflecting Bragg gratings is used as the output coupler for mode selection. By inserting those BP-SA solutions in the laser cavity, the maximum single longitude mode, Q-switched output powers of 126mW at 692.5 kHz and 149mW at 630.3 kHz are achieved at the pump power of 8.0 W, corresponding to the pulse durations of 144 ns and 196 ns, respectively. Moreover, longitudinal-mode characteristics of Q-switched output laser in different optical cavity lengths based on two-kind BP-SA solution concentrations are investigated. Our results show that BP-SA could also be developed as an effective SA for the Q-switched, single longitudinal mode pulse laser.
入藏号: WOS:000394544300014
ISSN: 0256-307X
eISSN: 1741-3540
第 231 条,共 255 条
标题: Latent Semantic Minimal Hashing for Image Retrieval
作者: Lu, XQ (Lu, Xiaoqiang); Zheng, XT (Zheng, Xiangtao); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON IMAGE PROCESSING 卷: 26 期: 1 页: 355-368 DOI: 10.1109/TIP.2016.2627801 出版年: JAN 2017
摘要: Hashing-based similarity search is an important technique for large-scale query-by-example image retrieval system, since it provides fast search with computation and memory efficiency. However, it is a challenge work to design compact codes to represent original features with good performance. Recently, a lot of unsupervised hashing methods have been proposed to focus on preserving geometric structure similarity of the data in the original feature space, but they have not yet fully refined image features and explored the latent semantic feature embedding in the data simultaneously. To address the problem, in this paper, a novel joint binary codes learning method is proposed to combine image feature to latent semantic feature with minimum encoding loss, which is referred as latent semantic minimal hashing. The latent semantic feature is learned based on matrix decomposition to refine original feature, thereby it makes the learned feature more discriminative. Moreover, a minimum encoding loss is combined with latent semantic feature learning process simultaneously, so as to guarantee the obtained binary codes are discriminative as well. Extensive experiments on several wellknown large databases demonstrate that the proposed method outperforms most state-of-the-art hashing methods.
入藏号: WOS:000397221700002
作者识别号:
作者        ResearcherID 号        ORCID 号
Lu, Xiaoqiang                  0000-0002-7037-5188
ISSN: 1057-7149
eISSN: 1941-0042
第 232 条,共 255 条
标题: Emotional textile image classification based on cross-domain convolutional sparse autoencoders with feature selection
作者: Li, ZH (Li, Zuhe); Fan, YY (Fan, Yangyu); Liu, WH (Liu, Weihua); Yu, ZQ (Yu, Zeqi); Wang, FQ (Wang, Fengqin)
来源出版物: JOURNAL OF ELECTRONIC IMAGING 卷: 26 期: 1 文献号: 013022 DOI: 10.1117/1.JEI.26.1.013022 出版年: JAN 2017
摘要: We aim to apply sparse autoencoder-based unsupervised feature learning to emotional semantic analysis for textile images. To tackle the problem of limited training data, we present a cross-domain feature learning scheme for emotional textile image classification using convolutional autoencoders. We further propose a correlation-analysis-based feature selection method for the weights learned by sparse autoencoders to reduce the number of features extracted from large size images. First, we randomly collect image patches on an unlabeled image dataset in the source domain and learn local features with a sparse autoencoder. We then conduct feature selection according to the correlation between different weight vectors corresponding to the autoencoder's hidden units. We finally adopt a convolutional neural network including a pooling layer to obtain global feature activations of textile images in the target domain and send these global feature vectors into logistic regression models for emotional image classification. The cross-domain unsupervised feature learning method achieves 65% to 78% average accuracy in the cross-validation experiments corresponding to eight emotional categories and performs better than conventional methods. Feature selection can reduce the computational cost of global feature extraction by about 50% while improving classification performance. (C) 2017 SPIE and IS&T
入藏号: WOS:000397059800052
ISSN: 1017-9909
eISSN: 1560-229X
第 233 条,共 255 条
标题: Efficient point matching under uneven and dramatic illumination changes
作者: Yang, R (Yang, Rui); Liu, ZH (Liu, Zhaohui); Yang, T (Yang, Tao); Li, WH (Li, Wenhao)
来源出版物: JOURNAL OF ELECTRONIC IMAGING 卷: 26 期: 1 文献号: 013001 DOI: 10.1117/1.JEI.26.1.013001 出版年: JAN 2017
摘要: Point matching under illumination changes is significant for many vision information applications. However, the uneven and dramatic illumination variations model is rarely considered in existing point matching algorithms. Therefore, a method to match features efficiently under uneven and dramatic illumination changes is presented. This method extracts and describes illumination invariant interesting points from matched multibrightness layers that are obtained by a set of contrast stretching functions and prior information based on original images. Layers matching is insensitive to large unevenness of illumination changes and provides similar images in brightness and structure, so the effects of large uneven illumination changes can be reduced greatly. This algorithm is compatible with most detectors and descriptors. To accelerate the computing speed, the features from the accelerated segment test detector and the improved speeded up robust features descriptor are chosen in this paper. In addition, the combination of priority Hamming distance matching and Lowe's matching algorithms is first proposed to increase the matching speed. This method is generic and can be used in most point matching under all varying illumination conditions. Experimental results demonstrate that the proposed method improves the quality of matched points significantly. (C) 2017 SPIE and IS&T
入藏号: WOS:000397059800031
ISSN: 1017-9909
eISSN: 1560-229X
第 234 条,共 255 条
标题: Character and mechanism of surface micromachining for C/SiC composites by ultrashort plus laser
作者: Wang, J (Wang, J.); Liu, Y (Liu, Y.); Wang, C (Wang, C.); Li, W (Li, W.); Yang, X (Yang, X.); Zhang, Q (Zhang, Q.); Cheng, L (Cheng, L.); Zhang, L (Zhang, L.)
来源出版物: ADVANCES IN APPLIED CERAMICS 卷: 116 期: 2 页: 99-107 DOI: 10.1080/17436753.2016.1257101 出版年: 2017
摘要: A new surface micromachining way of ultrashort plus laser for C/SiC composites with high quality and efficiency was demonstrated, including picosecond and femtosecond laser. Surface morphologies, element content and bonding states of C/SiC composites were analysed in detail after machined by picosecond and femtosecond laser power respectively. For femtosecond laser machining, the amount of nanoparticles increased with increasing laser power. At 20 and 50mW, Si-C, C-C and Si-O bonds existed in nanoparticles, while Si-C bonds disappeared at 70mW. For picosecond laser machining, cauliflower-like particles and periodic ripple with certain depth were formed distinctly. Furthermore, thermal ablation phenomenon occurred, and only Si-O bonds existed in particles due to the oxidation of the carbon fibres and SiC matrix. The results showed that femtosecond laser with low power was more suitable to the surface machining due to better machining quality and less machining damage compared with high power picosecond laser.
入藏号: WOS:000395242500006
ISSN: 1743-6753
eISSN: 1743-6761
第 235 条,共 255 条
标题: An approach to the dynamic modeling and sliding mode control of the constrained robot
作者: Shi, H (Shi, Heng); Liang, YB (Liang, Yanbing); Liu, ZH (Liu, Zhaohui)
来源出版物: ADVANCES IN MECHANICAL ENGINEERING 卷: 9 期: 2 文献号: 1687814017690470 DOI: 10.1177/1687814017690470 出版年: JAN 1 2017
摘要: An approach to the dynamic modeling and sliding mode control of the constrained robot is proposed in this article. On the basis of the Udwadia-Kalaba approach, the explicit equation of the constrained robot system is obtained first. This equation is applicable to systems with either holonomic or non-holonomic constraints, as well as with either ideal or non-ideal constraint forces. Second, fully considering the uncertainty of the non-ideal force, that is, the dynamic friction in the constrained robot system, the sliding mode control algorithm is put forward to trajectory tracking of the end-effector on a vertical constrained surface to obtain actual values of the unknown constraint force. Moreover, model order reduction method is innovatively used in the Udwadia-Kalaba approach and sliding mode controller to reduce variables and simplify the complexity of the calculation. Based on the demonstration of this novel method, a detailed robot system example is finally presented.
入藏号: WOS:000394864400004
ISSN: 1687-8140
第 236 条,共 255 条
标题: Comparison of nanoparticle generation by two plasma techniques: Dielectric barrier discharge and spark discharge
作者: Jiang, L (Jiang, Lun); Li, Q (Li, Qing); Zhu, DD (Zhu, Dandan); Attoui, M (Attoui, Michel); Deng, Z (Deng, Zhi); Tang, J (Tang, Jie); Jiang, JK (Jiang, Jingkun)
来源出版物: AEROSOL SCIENCE AND TECHNOLOGY 卷: 51 期: 2 页: 206-213 DOI: 10.1080/02786826.2016.1260681 出版年: 2017
摘要: Dielectric barrier discharge ( DBD) and spark discharge, two versatile atmospheric pressure plasma-based techniques, have been employed to generate nanoparticles. This study compares the characteristics of metal nanoparticles generated by a DBD reactor and a spark discharge generator with argon as the working gas. The gas temperature in the discharge region of the DBD reactor remained near room temperature, while that of the spark reactor varied from 470 to 1120 K and generally increased with increasing applied voltage amplitude in the range of 2-10 kV and driving frequency in the range of 1-10 kHz. Comparing to spark-generated nanoparticles under the same voltage, frequency, and flow rate, DBD-generated nanoparticles have smaller sizes, better monodispersity, and lower number concentrations. The number concentration of DBD-generated particles decreases significantly under high working voltage and frequency, while the number concentration of spark-generated particles increases with increasing working voltage. Under continuous operations over several hours, the DBD reactor has better temporal stability in generating nanoparticles than the spark generator.
入藏号: WOS:000394661600009
作者识别号:
作者        ResearcherID 号        ORCID 号
Li, Qing         B-7371-2016         0000-0003-0587-1748
ISSN: 0278-6826
eISSN: 1521-7388
第 237 条,共 255 条
标题: Automatic Lumen Segmentation in Intravascular Optical Coherence Tomography Images Using Level Set
作者: Cao, YH (Cao, Yihui); Cheng, K (Cheng, Kang); Qin, XJ (Qin, Xianjing); Yin, QY (Yin, Qinye); Li, JA (Li, Jianan); Zhu, R (Zhu, Rui); Zhao, W (Zhao, Wei)
来源出版物: COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 文献号: 4710305 DOI: 10.1155/2017/4710305 出版年: 2017
摘要: Automatic lumen segmentation from intravascular optical coherence tomography (IVOCT) images is an important and fundamental work for diagnosis and treatment of coronary artery disease. However, it is a very challenging task due to irregular lumen caused by unstable plaque and bifurcation vessel, guide wire shadow, and blood artifacts. To address these problems, this paper presents a novel automatic level set based segmentation algorithm which is very competent for irregular lumen challenge. Before applying the level set model, a narrow image smooth filter is proposed to reduce the effect of artifacts and prevent the leakage of level set meanwhile. Moreover, a divide-and-conquer strategy is proposed to deal with the guide wire shadow. With our proposed method, the influence of irregular lumen, guide wire shadow, and blood artifacts can be appreciably reduced. Finally, the experimental results showed that the proposed method is robust and accurate by evaluating 880 images from 5 different patients and the average DSC value was 98.1% +/- 1.1%.
入藏号: WOS:000394953300001
ISSN: 1748-670X
eISSN: 1748-6718
第 238 条,共 255 条
标题: Analysis of Partial Crystallization in Yb3+ Doped Aluminophosphosilicate Fiber Preforms Prepared with Organic Chelate Precursor Doping Technique
作者: Luo, R (Luo, Rong); Li, WN (Li, Weinan); Hou, CQ (Hou, Chaoqi); Wang, PF (Wang, Pengfei)
来源出版物: ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY 卷: 6 期: 4 页: P138-P143 DOI: 10.1149/2.0151704jss 出版年: 2017
摘要: Yb3+ doped aluminophosphosilicate fiber preforms have been prepared by modified chemical vapor deposition (MCVD) with organic chelate precursor doping technique (OCD). It was found that the flow ratio of Yb(thd)(3)/POCl3 had an important influence on partial crystallization in the preform cores. The wholly transparent core was obtained when the flow ratio of Yb(thd)(3)/POCl3 ranged in 0.71: 1-0.82:1. Crystallization occurred during etching process when the Yb(thd)(3)/POCl3 flow ratio was over 0.83:1, corresponding to a doping ratio of Yb2O3/P2O5 larger than 1.01:1, as characterized by electron probe microanalysis (EPMA). X-ray photoelectric spectroscopy (XPS) analysis indicated exsistence of P in the quasi-metaphosphate [PO4] bond structures in the crystallized area. Raman spectra displayed characteristic peaks of silica glasses except 1330 cm(-1) Raman peaks, which can be assigned to P=O bond due to the presence of quasi-metaphosphate [PO4] units. When the content ratio of Yb2O3/ P2O5 exceeded 1.01: 1, Al was depleted and P was enriched, and the Yb3+ ions was mainly connected with the quasi-metaphosphate [PO4] units, which weakened the role of P and Al preventing Yb3+ ions clustering. As a result, crystallization occurred. And this schematic glass structural model was proposed for the partially crystallized preform core. (C) 2017 The Electrochemical Society.
入藏号: WOS:000393988500009
ISSN: 2162-8769
第 239 条,共 255 条
标题: Depth profiling of the refractive index from probe beam deflections induced by a serrated pump illumination on GaAs
作者: Liang, LL (Liang, Lingliang); Tian, JS (Tian, Jinshou); Wang, T (Wang, Tao); Wu, SL (Wu, Shengli); Li, FL (Li, Fuli); Gao, GL (Gao, Guilong)
来源出版物: JOURNAL OF MODERN OPTICS 卷: 64 期: 5 页: 431-438 DOI: 10.1080/09500340.2016.1241902 出版年: 2017
摘要: We demonstrate a method to experimentally quantify the distribution with depth of photo-induced refractive index generated by a pump illumination, which is spatially modulated by a serrated mask on the surface of bulk GaAs. This photo-induced refractive index change distributes inhomogeneously with depth thus deflecting the probe beam transversely passing through the depth direction. The refractive index distribution with depth is deduced from the set of deflections of probe beam with respect to the propagating distances, which is collected experimentally in a pump probe arrangement. The obtained set of deflections of probe beam is theoretically proved to be reliable.
入藏号: WOS:000394546700001
ISSN: 0950-0340
eISSN: 1362-3044
第 240 条,共 255 条
标题: Ground-based optical detection of low-dynamic vehicles in near-space
作者: Jing, N (Jing, Nan); Li, C (Li, Chuang); Zhong, PF (Zhong, Peifeng)
来源出版物: OPTICAL ENGINEERING 卷: 56 期: 1 文献号: 014107 DOI: 10.1117/1.OE.56.1.014107 出版年: JAN 2017
摘要: Ground-based optical detection of low-dynamic vehicles in near-space is analyzed to detect, identify, and track high-altitude balloons and airships. The spectral irradiance of a representative vehicle on the entrance pupil plane of ground-based optoelectronic equipment was obtained by analyzing the influence of its geometry, surface material characteristics, infrared self-radiation, and the reflected background radiation. Spectral radiation characteristics of the target in both clear weather and complex meteorological weather were simulated. The simulation results show the potential feasibility of using visible-near-infrared (VNIR) equipment to detect objects in clear weather and long-wave infrared (LWIR) equipment to detect objects in complex meteorological weather. A ground-based VNIR and LWIR optoelectronic experimental setup is built to detect low-dynamic vehicles in different weather. A series of experiments in different weather are carried out. The experiment results validate the correctness of the simulation results. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
入藏号: WOS:000396389400059
ISSN: 0091-3286
eISSN: 1560-2303
第 241 条,共 255 条
标题: Robust Sparse Coding for Mobile Image Labeling on the Cloud
作者: Tao, DP (Tao, Dapeng); Cheng, J (Cheng, Jun); Gao, XB (Gao, Xinbo); Li, XL (Li, Xuelong); Deng, C (Deng, Cheng)
来源出版物: IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 卷: 27 期: 1 特刊: SI 页: 62-72 DOI: 10.1109/TCSVT.2016.2539778 出版年: JAN 2017
摘要: With the rapid development of the mobile service and online social networking service, a large number of mobile images are generated and shared on the social networks every day. The visual content of these images contains rich knowledge for many uses, such as social categorization and recommendation. Mobile image labeling has, therefore, been proposed to understand the visual content and received intensive attention in recent years. In this paper, we present a novel mobile image labeling scheme on the cloud, in which mobile images are first and efficiently transmitted to the cloud by Hamming compressed sensing, such that the heavy computation for image understanding is transferred to the cloud for quick response to the queries of the users. On the cloud, we design a sparse correntropy framework for robustly learning the semantic content of mobile images, based on which the relevant tags are assigned to the query images. The proposed framework (called maximum correntropy-based mobile image labeling) is very insensitive to the noise and the outliers, and is optimized by a half-quadratic optimization technique. We theoretically show that our image labeling approach is more robust than the squared loss, absolute loss, Cauchy loss, and many other robust loss function-based sparse coding methods. To further understand the proposed algorithm, we also derive its robustness and generalization error bounds. Finally, we conduct experiments on the PASCAL VOC' 07 data set and empirically demonstrate the effectiveness of the proposed robust sparse coding method for mobile image labeling.
入藏号: WOS:000393796500006
ISSN: 1051-8215
eISSN: 1558-2205
第 242 条,共 255 条
标题: Plasmonic Black Absorbers for Enhanced Photocurrent of Visible-Light Photocatalysis
作者: Tan, FR (Tan, Furui); Wang, N (Wang, Ning); Lei, DY (Lei, Dang Yuan); Yu, WX (Yu, Weixing); Zhang, XM (Zhang, Xuming)
来源出版物: ADVANCED OPTICAL MATERIALS 卷: 5 期: 2 文献号: UNSP 1600399 DOI: 10.1002/adom.201600399 出版年: JAN 2017
摘要: Plasmonic resonance of noble metal nanoparticles can drastically enhance the visible response of wide-bandgap photocatalysts such as TiO2, but the current technology has two fundamental problems: narrow absorption band and low absorption, which limit the energy efficiency of photocatalysis using sunlight. Here, an original plasmonic black absorber is reported, which sandwiches a 150 nm TiO2 layer between a layer of random Au nanoparticles and a rough Au surface (200 nm thick). The combined plasmonic effect of the Au nanoparticles and the Au rough surface enables a strong absorption (72%-91%) over 400-900 nm and a significantly (20-fold) enhanced photocurrent as compared to the bare TiO2 film. The strong absorption to visible and near infrared light, and the much enhanced photocurrent make the black absorber an ideal material for solar applications such as photocatalytic, photosynthetic, photovoltaic, and photothermal systems.
入藏号: WOS:000393199900001
作者识别号:
作者        ResearcherID 号        ORCID 号
Lei, Dangyuan         B-9812-2011         0000-0002-8963-0193
Zhang, Xuming                  0000-0002-9326-5547
ISSN: 2195-1071
第 243 条,共 255 条
标题: Optical spectroscopic characterizations of laser irradiated olivine grains
作者: Yang, YZ (Yang, Yazhou); Zhang, H (Zhang, Hao); Wang, ZW (Wang, Ziwei); Yuan, Y (Yuan, Ye); Li, SL (Li, Shaolin); Hsu, WB (Hsu, Weibiao); Liu, CJ (Liu, Chujian)
来源出版物: ASTRONOMY & ASTROPHYSICS 卷: 597 文献号: A50 DOI: 10.1051/0004-6361/201629327 出版年: JAN 2017
摘要: Context. Visible and near-infrared spectra of asteroids are known to be susceptible to nanophase irons produced by space weathering processes, thus making mineral identifications difficult. Mid-infrared spectroscopy may retain more mineral features owing to its lattice vibrational nature.
Aims. We investigate the structure and reflectance spectral feature changes of olivine grains before and after simulated space weathering.
Methods. We irradiate olivine grains by using pulsed laser to simulate varying degrees of micrometeorite bombardments. Reflectance measurements from 0.5 to 25 mu m and radiative transfer calculations were carried out in order to compare them with each other.
Results. Both the experimental simulations and modeling results indicate that the mid-infrared spectral features of olivine grains can survive the intense irradiations. Although the Christansen Feature is slightly shifted to longer wavelength, major vibrational bands remain essentially unchanged, because the lattice structure is quite immune to even the strongest irradiations, as revealed by both the X-ray diffraction and Raman scattering measurements.
Conclusions. Mid-infrared spectroscopy is much more immune to productions of nanophase irons and amorphous materials and thus may be used more reliably in remote detections of minerals on asteroid surfaces.
入藏号: WOS:000392392900106
ISSN: 1432-0746
第 244 条,共 255 条
标题: Proton-implanted optical waveguides fabricated in Er3+-doped phosphate glasses
作者: Liu, CX (Liu, Chun-Xiao); Shen, XL (Shen, Xiao-Liang); Guo, HT (Guo, Hai-Tao); Li, WN (Li, Wei-Nan); Wei, W (Wei, Wei)
来源出版物: OPTIK 卷: 131 页: 132-137 DOI: 10.1016/j.ijleo.2016.11.080 出版年: 2017
摘要: Er3+-doped phosphate glass is suitable to design and develop integrated photonic structures. Ion implantation is one of the most promising fabrication techniques for producing optical waveguides. In this work, we have combined Er3+-doped phosphate glass and ion implantation in order to improve the performances of waveguides. The proton-implanted Er3+-doped phosphate glass waveguides have been fabricated under implantation parameters with energies of (500 +550) key and fluences of (1.0 + 2.0) x 10(16) ions/cm(2). The guiding properties of the planar waveguide have been investigated at the wavelength of 632.8 nm through the prism-coupling system and the end-face coupling arrangement. Irradiation induced damage and refractive index modulation have been simulated by the stopping and range of ions in matter 2010 and the intensity calculation method, respectively. It is an important step to the fabrication of rare-earth-doped optical integrated devices. (C) 2016 Elsevier GmbH. All rights reserved.
入藏号: WOS:000392782300017
ISSN: 0030-4026
第 245 条,共 255 条
标题: Athermal design of refractive/diffractive hybrid infrared optical system
作者: Jiang, YR (Jiang, Yanru); Wang, J (Wang, Jing); Xie, QK (Xie, Qingkun); Zhang, WF (Zhang, Wenfei); Qu, ES (Qu, Enshi)
来源出版物: OPTIK 卷: 131 页: 592-597 DOI: 10.1016/j.ijleo.2016.11.195 出版年: 2017
摘要: Regarding the poor work conditions of military infrared optical instruments, there is usually a strong demand for athermalization and high resolution design. According to the properties of diffractive components in the optical passive athermalization, a diffractive-refractive hybrid infrared optical system working at 8 um-12 um is designed. It only contains four lenses with two aspheric and two diffractive surfaces, resulting in solutions with reducing overall size and weight, as well as enhancing performance characteristics. The MTF of this system demonstrates the optical system can realize athermalization over the temperature range from -40 degrees C to 60 degrees C. In addition, the chromatic aberration and second spectrum are corrected simultaneously. (C) 2016 Published by Elsevier GmbH.
入藏号: WOS:000392782300071
ISSN: 0030-4026
第 246 条,共 255 条
标题: A robust stereo matching algorithm based on improved epipolar distance transformation
作者: Yue, Q (Yue, Qi); Ma, CW (Ma, Caiwen); Cao, XQ (Cao, Xiaoqian)
来源出版物: OPTIK 卷: 130 页: 91-98 DOI: 10.1016/j.ijleo.2016.11.054 出版年: 2017
摘要: Aim to the problem of initial epipolar distance transformation algorithm is sensitive to illumination and depth discontinuous, an improved stereo matching algorithm is proposed. In Delta-Gama log-chromaticity space, Gamma correction coefficient is computed firstly according to raw disparity map which is used to Modified the similarity function bandwidth. Secondly, by employing image structure and color features, the segment of epipolar is obtained adaptively. At last, final disparity map is acquired by belief propagation method. Experimental results demonstrate the effectiveness of the proposed transform in illumination change regions and discontinuities regions. The matching rate of proposed algorithm is improved about 60%, comparing with the initial epipolar distance transformation algorithm and state-of-art algorithm such as ANCC(Adaptive Normalized Cross Correlation). (C) 2016 Elsevier GmbH. All rights reserved.
入藏号: WOS:000391777400013
ISSN: 0030-4026
第 247 条,共 255 条
标题: Study of visibility enhancement of hazy images based on dark channel prior in polarimetric imaging
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: OPTIK 卷: 130 页: 123-130 DOI: 10.1016/j.ijleo.2016.11.047 出版年: 2017
摘要: During past decades, lots of efforts on image dehazing have been made based on either computer vision or physical models. In this paper, based on the combination of the polarimetric imaging and the dark channel prior techniques, we propose a novel haze-removal method. On the one hand, the former technique ensures this method has the advantage of keeping the detailed information which might be almost vanished in hazy images; on the other hand, the latter technique provides a much easier way to precisely estimate the key parameters, such as the global atmospheric light and the degree of polarization of the airlight. Moreover, in order to realize the automatically dehazing process with our method, a dynamic bias factor is creatively introduced into the dehazing process by use of the evaluation function Entropy, ensuring excellent dehazed image being automatically obtained while not involving any other human-computer interaction. Experimental results indicate that our dehazing method can not only enhance the visibility of the hazy images effectively, but also preserve the details considerably. In addition, it is also found that this method is useful and effective for thin, medium and dense haze conditions, and thus shows a good robustness and universality. (C) 2016 Elsevier GmbH. All rights reserved.
入藏号: WOS:000391777400017
作者识别号:
作者        ResearcherID 号        ORCID 号
Ren, Liyong         F-5518-2014         0000-0002-7547-7511
ISSN: 0030-4026
第 248 条,共 255 条
标题: Changes in endogenous hormones and H2O2 burst during shoot organogenesis in TDZ-treated Saussurea involucrate explants
作者: Guo, B (Guo, Bin); He, W (He, Wei); Zhao, Y (Zhao, Yan); Wu, YD (Wu, Yandi); Fu, YP (Fu, Yanping); Guo, J (Guo, Juan); Wei, YH (Wei, Yahui)
来源出版物: PLANT CELL TISSUE AND ORGAN CULTURE 卷: 128 期: 1 页: 1-8 DOI: 10.1007/s11240-016-1069-3 出版年: JAN 2017
摘要: Thidiazuron [N-phenyl-N-(1, 2, 3-thidiazol-5-yl) urea, TDZ] treatment significantly improved shoot morphogenesis of Saussurea involucrata Kar. Et Kir (S. involucrata) leaf explants. The biochemical mechanisms underlying TDZ-induced shoot organogenesis were investigated by measuring endogenous plant growth hormones, H2O2, as well as the activities of superoxide dismutase (SOD) and catalase (CAT). The levels of endogenous gibberellic A3 (GA(3)) and zeatin (ZT) significantly increased in leaf explants subject to a 28-day treatment than the controls. However, extending exposure time to TDZ inhibited GA(3) accumulation. At the same time, the SOD activity increased significantly until the 28th of TDZ treatment time and the CAT activity reduced simultaneously, which was closely linked with the significant increase in H2O2 concentrations in the explants. And there was a sharply promotion after the 35 day of culture time if the plant tissue was always in medium contained, which was in company with the cell activity decreased. We propose that a combination of increased GA(3), ZT, and H2O2 concentration is the basis for the enhanced shoot morphogenesis in response to TDZ treatment. These results provide a starting point for an improved understanding of the biochemical mechanisms underlying TDZ-induced shoot organogenesis of S. involucrata.
入藏号: WOS:000391942400001
ISSN: 0167-6857
eISSN: 1573-5044
第 249 条,共 255 条
标题: Learning Sampling Distributions for Efficient Object Detection
作者: Pang, YW (Pang, Yanwei); Cao, JL (Cao, Jiale); Li, XL (Li, Xuelong)
来源出版物: IEEE TRANSACTIONS ON CYBERNETICS 卷: 47 期: 1 页: 117-129 DOI: 10.1109/TCYB.2015.2508603 出版年: JAN 2017
摘要: Object detection is an important task in computer vision and machine intelligence systems. Multistage particle windows (MPW), proposed by Gualdi et al., is an algorithm of fast and accurate object detection. By sampling particle windows (PWs) from a proposal distribution (PD), MPW avoids exhaustively scanning the image. Despite its success, it is unknown how to determine the number of stages and the number of PWs in each stage. Moreover, it has to generate too many PWs in the initialization step and it unnecessarily regenerates too many PWs around object-like regions. In this paper, we attempt to solve the problems of MPW. An important fact we used is that there is a large probability for a randomly generated PW not to contain the object because the object is a sparse event relative to the huge number of candidate windows. Therefore, we design a PD so as to efficiently reject the huge number of nonobject windows. Specifically, we propose the concepts of rejection, acceptance, and ambiguity windows and regions. Then, the concepts are used to form and update a dented uniform distribution and a dented Gaussian distribution. This contrasts to MPW which utilizes only on region of support. The PD of MPW is acceptance-oriented whereas the PD of our method (called iPW) is rejection-oriented. Experimental results on human and face detection demonstrate the efficiency and the effectiveness of the iPW algorithm. The source code is publicly accessible.
入藏号: WOS:000391481400010
PubMed ID: 26742154
ISSN: 2168-2267
eISSN: 2168-2275
第 250 条,共 255 条
标题: In situ measurement of the topological charge of a perfect vortex using the phase shift method
作者: Ma, HX (Ma, Haixiang); Li, XZ (Li, Xinzhong); Tai, YP (Tai, Yuping); Li, HH (Li, Hehe); Wang, JG (Wang, Jingge); Tang, MM (Tang, Miaomiao); Wang, YS (Wang, Yishan); Tang, J (Tang, Jie); Nie, ZG (Nie, Zhaogang)
来源出版物: OPTICS LETTERS 卷: 42 期: 1 页: 135-138 DOI: 10.1364/OL.42.000135 出版年: JAN 1 2017
摘要: We propose a method to determine the topological charge (TC) of a perfect vortex. With the phase shift technique, the perfect vortex and its conjugate beam exactly overlap and interfere. Consequently, the TC of a perfect vortex is determined by counting the number of interference fringes. This proposed method enables in situ determination of the TC of the perfect vortex without the need for additional optical elements, and it is immune to environmental vibration and parasitic interference. (C) 2016 Optical Society of America
入藏号: WOS:000391396800036
PubMed ID: 28059197
ISSN: 0146-9592
eISSN: 1539-4794

第 251 条,共 255 条
标题: Facile synthesis of porous nitrogen-doped holey graphene as an efficient metal-free catalyst for the oxygen reduction reaction
作者: Qin, L (Qin, Li); Ding, RM (Ding, Ruimin); Wang, HX (Wang, Huixiang); Wu, JH (Wu, Jianghong); Wang, CH (Wang, Conghui); Zhang, CH (Zhang, Chenghua); Xu, Y (Xu, Yao); Wang, L (Wang, Liancheng); Lv, BL (Lv, Baoliang)
来源出版物: NANO RESEARCH 卷: 10 期: 1 页: 305-319 DOI: 10.1007/s12274-016-1293-5 出版年: JAN 2017
摘要: Nitrogen-doped graphene is a promising candidate for the replacement of noble metal-based electrocatalysts for oxygen reduction reactions (ORRs). The addition of pores and holes into nitrogen-doped graphene enhances the ORR activity by introducing abundant exposed edges, accelerating mass transfer, and impeding aggregation of the graphene sheets. Herein, we present a straightforward but effective strategy for generating porous holey nitrogen-doped graphene (PHNG) via the pyrolysis of urea and magnesium acetate tetrahydrate. Due to the combined effects of the in situ generated gases and MgO nanoparticles, the synthesized PHNGs featured not only numerous out-of-plane pores among the crumpled graphene sheets, but also interpenetrated nanoscale (5-15 nm) holes in the assembled graphene. Moreover, the nitrogen doping configurations of PHNG were optimized by post-thermal treatments at different temperatures. It was found that the overall content of pyridinic and quaternary nitrogen positively correlates with the ORR activity; in particular, pyridinic nitrogen generates the most desirable characteristics for the ORR. This work reveals new routes for the synthesis of PHNG-based materials and elucidates the contributions of various nitrogen species to ORRs.
入藏号: WOS:000390066000027
作者识别号:
作者        ResearcherID 号        ORCID 号
wang, liancheng         H-9911-2013         0000-0003-1117-1326
Lv, Baoliang         H-2311-2013         0000-0001-8288-6076
ISSN: 1998-0124
eISSN: 1998-0000
第 252 条,共 255 条
标题: Optimization design of a 20-in. elliptical MCP-PMT
作者: Chen, P (Chen, Ping); Tian, JS (Tian, Jinshou); Wei, YL (Wei, Yonglin); Liu, HL (Liu, Hulin); Sai, XF (Sai, Xiaofeng); He, JP (He, Jianping); Chen, L (Chen, Lin); Wang, X (Wang, Xing); Lu, Y (Lu, Yu)
来源出版物: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 卷: 841 页: 104-108 DOI: 10.1016/j.nima.2016.10.036 出版年: JAN 1 2017
摘要: This paper describes the simulation work for optimizing the newly developed 20-in. elliptical MCP-PMT by enlarging the outside diameters of the two focusing electrodes and the open area of the glass bulb. Effects of biasing voltages applied to the two focusing electrodes and the MCP input facet are studied. With the new design of the 20 in. MCP-PMT, the transit time spread of the prototype can be less than 3 ns and the collection efficiency is as much as the present prototype.
入藏号: WOS:000389394300014
ISSN: 0168-9002
eISSN: 1872-9576
第 253 条,共 255 条
标题: Study on the key technologies of a high-speed CMOS camera
作者: Jiang, BT (Jiang, Baotan); Pan, ZB (Pan, Zhibin); Qiu, YH (Qiu, Yuehong)
来源出版物: OPTIK 卷: 129 页: 100-107 DOI: 10.1016/j.ijleo.2016.10.056 出版年: 2017
摘要: The high-speed CMOS camera can be widely applied in image technology detection, image measurement, video monitoring, and satellite remote sensing. Given the large image data volume, many technical problems may be encountered in acquisition and transfer of image data and real-time processing. CMV4000 from CMOSIS Company has been selected as image sensor to research application problems. The high-frame and high-definition industrial camera has been designed based on CMV4000 image sensor, FPGA, DDR2 SDRAM highspeed memory chip, and USB3.0 technology. The camera is made up of data automatic alignment module, image acquisition module, memory module, and transfer module. These modules have realized data alignment, acquisition, cache, and transfer of high-speed data. An automatic alignment module is proposed which based on the sliding window consists of register for high-speed image sensor with multi-channel LVDS interface. This module can automatically identify training data sent by LVDS serial channel, and lock the sliding window when finding "Training Pattern", then realize automatic alignment and synchronization for high-speed and multi-channel data. (C) 2016 Elsevier GmbH. All rights reserved.
入藏号: WOS:000389096100014
ISSN: 0030-4026
第 254 条,共 255 条
标题: The theoretical investigation of the impact of two-photon absorption and free-carrier absorption on phase-sensitive amplification in silicon waveguides
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: JOURNAL OF MODERN OPTICS 卷: 64 期: 1 页: 93-99 DOI: 10.1080/09500340.2016.1208850 出版年: 2017
摘要: We investigate the influence of two-photon absorption (TPA) and free-carrier absorption (FCA) on phase-sensitive amplification (PSA) process in a dispersion engineered silicon strip waveguide at the telecom wavelengths. The phase-dependent gain and phase-to-phase transfer functions as well as the phase regeneration capacity of PSA are numerically analysed. It is found that TPA and FCA will suppress the phase-sensitive extinction ratio (PER) and the efficiency of phase squeezing. Moreover, the phase regeneration capability of silicon waveguide-based PSA is investigated by comparing the regenerated signal waveforms at a different signal power with/without TPA and FCA. Our results have potential application in all-optical signal regeneration.
入藏号: WOS:000386204300012
ISSN: 0950-0340
eISSN: 1362-3044
第 255 条,共 255 条
标题: Femtosecond Passively Er-Doped Mode-Locked Fiber Laser With WS2 Solution Saturable Absorber
作者: Li, L (Li, Lu); Su, YL (Su, Yulong); Wang, YG (Wang, Yonggang); Wang, X (Wang, Xi); Wang, YS (Wang, Yishan); Li, XH (Li, Xiaohui); Mao, D (Mao, Dong); Si, JH (Si, Jinhai)
来源出版物: IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 卷: 23 期: 1 文献号: 1100306 DOI: 10.1109/JSTQE.2016.2538640 出版年: JAN-FEB 2017
摘要: This study presents the femtosecond fundamental and harmonic mode-locked Er-doped fiber laser with WS2 solution saturable absorber (SSA). The SA is fabricated based on a D-shaped fiber (DF) embedded in WS2 nanosheets solution. Such WS2 solution has virtues of good antioxidant capacity, excellent scattering resistance, high heat dissipation, and high damage threshold. This kind of SA shows a modulation depth of 11%, a saturable intensity I-sat of 5 MW/cm(2), and nonsaturable loss of 18%. By employing DF-WS2 SSA, a stable mode-locked fiber laser is achieved with repetition rate of 10.2 MHz and pulse duration of 660 fs. At the pump power of 350 mW, 460.7-MHz repetition rate harmonic mode-locking (HML) operation is also obtained, which corresponds to 45th harmonics of the fundamental cavity repetition rate. The pulse duration is 710 fs and signal-to-noise ratio is 66 dB, showing the excellent performance in HML fiber laser with SA. The results indicate that DF-WS2 solution can work as a potential SA for ultrafast nonlinear optics.
入藏号: WOS:000380347300001

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