Record 1 of 327

Title: Effect of different welding energy on microstructure and toughness of HAZ of low carbon bainitic steel

Author(s): Wang, H (Wang, Hong); Yang, L (Yang, Liang)

Source: INTERNATIONAL JOURNAL OF MODERN PHYSICS B  Volume: 34  Issue: 32  Article Number: 2050319  DOI: 10.1142/S0217979220503191  Published: DEC 30 2020  

Abstract: Low carbon bainitic steel (LCBS) with excellent combined properties is the first choice for materials of pipeline transiting geological disaster. However, welding will worsen its toughness. In this paper, three kinds of welding heat input were designed to study the relationship between the toughness and microstructure in the coarse grain zone of welding heat affect zone (CGHAZ) of LCBS. The evolution characteristics of the microstructure of LCBS and the CGHAZ, and impact fracture were investigated by optical microscopy (OM), scanning electron microscopy (SEM). The results indicated that microstructure of LCBS consists mainly of bainite ferrite (BF) and granular bainite (GB). Heat input for 22 kJ/cm, the original austenite grains become coarsening, the microstructure is a small amount of quasi polygonal ferrite (QF) and polygonal ferrite (PF), which exhibits low Charpy impact toughness. However, for heat input of 19 kJ/cm, the degree of grain coarsening is small and distribution of martensite-austenite (M-A) constituents is the chain. The statistics of image software show that with the increase of heat input (16-22 kJ/cm), the average grain size of original austenite is basically the same (25 um), which is mainly due to Nb solute drag restraint the growth of austenite grain.

Accession Number: WOS:000603659400015

Author Identifiers:

ISSN: 0217-9792

eISSN: 1793-6578

Record 2 of 327

Title: Spiculation Sign Recognition in a Pulmonary Nodule Based on Spiking Neural P Systems

Author(s): Qiu, S (Qiu, Shi); Sun, JT (Sun, Jingtao); Zhou, T (Zhou, Tao); Gao, GL (Gao, Guilong); He, ZN (He, Zhenan); Liang, T (Liang, Ting)

Source: BIOMED RESEARCH INTERNATIONAL  Volume: 2020  Article Number: 6619076  DOI: 10.1155/2020/6619076  Published: DEC 24 2020  

Abstract: The spiculation sign is one of the main signs to distinguish benign and malignant pulmonary nodules. In order to effectively extract the image feature of a pulmonary nodule for the spiculation sign distinguishment, a new spiculation sign recognition model is proposed based on the doctors' diagnosis process of pulmonary nodules. A maximum density projection model is established to fuse the local three-dimensional information into the two-dimensional image. The complete boundary of a pulmonary nodule is extracted by the improved Snake model, which can take full advantage of the parallel calculation of the Spike Neural P Systems to build a new neural network structure. In this paper, our experiments show that the proposed algorithm can accurately extract the boundary of a pulmonary nodule and effectively improve the recognition rate of the spiculation sign.

Accession Number: WOS:000607928500003

PubMed ID: 33426059

Author Identifiers:

ISSN: 2314-6133

eISSN: 2314-6141

Record 3 of 327

Title: Luminescence modulation behavior upon <i>in-situ</i> electric field of Sm<SUP>3+</SUP> doped KSr₂Nb₅O₁₅ ferroelectric ceramics

Author(s): Cao, SY (Cao, Shuyao); Chen, Q (Chen, Qian); Liu, JT (Liu, Junting); Wu, CY (Wu, Changying); Li, LL (Li, Leilei); Xu, J (Xu, Jie); Cheng, GH (Cheng, Guanghua); Gao, F (Gao, Feng)

Source: MATERIALS LETTERS  Volume: 281  Article Number: 128613  DOI: 10.1016/j.matlet.2020.128613  Published: DEC 15 2020  

Abstract: Sm3+ doped KSr2Nb5O15 (KSN-Sm) ceramics exhibiting the electro-photoluminescent coupling effect were prepared by two-step sintering technology. The microstructures, electrical and luminescent properties were characterized. In addition, the luminescence modulation behavior upon the application of an in-situ electric field was investigated. It was found that the luminescent emission intensity decreased with increasing in-situ dc bias, and a high modulation ratio of approximately 20%@20 kV/cm was achieved. This work demonstrates that KSN-based ferroelectric ceramics with the tetragonal tungsten bronze structure are promising optical materials with good luminescence modulation behavior. (C) 2020 Elsevier B.V. All rights reserved.

Accession Number: WOS:000581134200025

Author Identifiers:

ISSN: 0167-577X

eISSN: 1873-4979

Record 4 of 327

Title: Yb/Ce Codoped Aluminosilicate Fiber With High Laser Stability for Multi-kW Level Laser

Author(s): She, SF (She, Shengfei); Liu, B (Liu, Bo); Chang, C (Chang, Chang); Xu, YT (Xu, Yantao); Xiao, XS (Xiao, Xusheng); Cui, XX (Cui, Xiaoxia); Li, Z (Li, Zhe); Zheng, JK (Zheng, Jinkun); Gao, S (Gao, Song); Zhang, Y (Zhang, Yan); Li, YZ (Li, Yizhao); Zhou, ZY (Zhou, Zhenyu); Mei, L (Mei, Lin); Hou, CQ (Hou, Chaoqi); Guo, HT (Guo, Haitao)

Source: JOURNAL OF LIGHTWAVE TECHNOLOGY  Volume: 38  Issue: 24  Pages: 6924-6931  DOI: 10.1109/JLT.2020.3019740  Published: DEC 15 2020  

Abstract: Further power scaling and stable laser performance were demonstrated in the Yb/Ce codoped aluminosilicate fiber fabricated through low-temperature chelate gas phase deposition technique. The molar ratio of Ce/Yb was designed and optimized to be 0.58 for low background loss, effective photodarkening suppression, and no additional thermal load. The background loss of this active fiber was 4.7 dB/km and its photodarkening loss at equilibrium was as low as 3.9 dB/m at 633 nm. Benefiting from low-temperature deposition technique, the fiber showed uniform core composition devoid of clustering and central 'dip' of refractive index profile and 0.19 mol% Yb2O3 was homogeneously dissolved into the fiber core plus with 0.41 mol% Al2O3, 0.11 mol% Ce2O3, and 0.32 mol% SiF4. Based on a master oscillator power amplifier laser setup, 5.04 kW laser output at 1079.80 nm was achieved with a slope efficiency of 81.1%. Stabilized at 5kW-level laser for over 60 minutes, the output power presented almost no power degradation, directly confirming a noticeable photodarkening mitigation.

Accession Number: WOS:000594923000024

Author Identifiers:

ISSN: 0733-8724

eISSN: 1558-2213

Record 5 of 327

Title: Real-time continuous calibration method for an ultraviolet camera

Author(s): Wu, KJ (Wu, Kuijun); Feng, YT (Feng, Yutao); Xiong, YH (Xiong, Yuanhui); Duan, WM (Duan, Weimin); Yu, GB (Yu, Guangbao); Li, FQ (Li, Faquan)

Source: OPTICS LETTERS  Volume: 45  Issue: 24  Pages: 6851-6854  DOI: 10.1364/OL.410635  Published: DEC 15 2020  

Abstract: The accuracy of SO2 cameras is significantly determined by the ability to obtain an accurate calibration. This work presents a real-time continuous calibration method for SO2 cameras with a moderate resolution spectrometer by taking realistic radiative transfer into account. The effectiveness and accuracy of the proposed method have been verified through simulations and experiments. The calibration error can be reduced by about 20-80% compared with the commonly used cell calibration, especially for situations of long distance, poor visibility, or optically thick plumes. (C) 2020 Optical Society of America

Accession Number: WOS:000599793600071

PubMed ID: 33325912

ISSN: 0146-9592

eISSN: 1539-4794

Record 6 of 327

Title: Biomimetic curved compound-eye camera with a high resolution for the detection of distant moving objects

Author(s): Xu, HR (Xu, Huangrong); Zhang, YJ (Zhang, Yuanjie); Wu, DS (Wu, Dengshan); Zhang, G (Zhang, Geng); Wang, ZY (Wang, Ziyuan); Feng, XP (Feng, Xiangpeng); Hu, BL (Hu, Bingliang); Yu, WX (Yu, Weixing)

Source: OPTICS LETTERS  Volume: 45  Issue: 24  Pages: 6863-6866  DOI: 10.1364/OL.411492  Published: DEC 15 2020  

Abstract: In this Letter, we demonstrate the design and fabrication of a biomimetic curved compound-eye camera (BCCEC) with a high resolution for detecting distant moving objects purpose. In contrast to previously reported compound-eye cameras, our BCCEC has two distinct features. One is that the ommatidia of the compound eye are deployed on a curved surface which makes a large field of view (FOV) possible. The other is that each ommatidium has a relatively large optical entrance and long focal length so that a distant object can be imaged. To overcome the mismatch between the curved focal plane formed by the curved compound eye and the planar focal plane of the CMOS image sensor (CIS), an optical relay subsystem is introduced between the compound eye and the CIS. As a result, a BCCEC with 127 ommatidia in the compound eye is designed and fabricated to achieve a large FOV of up to 98 degrees x 98 degrees. The experimental results show that objects with a size of 100 mm can be dearly resolved at a distance of 25 m. The capture of the motion trajectories of a moving object is also demonstrated, which makes it possible to detect and track the moving targets in a huge FOV for security surveillance purposes. (C) 2020 Optical Society of America

Accession Number: WOS:000599793600074

PubMed ID: 33325915

Author Identifiers:

ISSN: 0146-9592

eISSN: 1539-4794

Record 7 of 327

Title: The analysis of electron scattering among multiplying layer in EBAPS using optimized Monte Carlo method

Author(s): Bai, JZ (Bai, Jinzhou); Bai, YL (Bai, Yonglin); Hou, X (Hou, Xun); Cao, WW (Cao, Weiwei); Yang, Y (Yang, Yang); Wang, B (Wang, Bo); Bai, XH (Bai, Xiaohong); Li, SQ (Li, Siqi)

Source: MODERN PHYSICS LETTERS B  Volume: 34  Issue: 34  Article Number: 2050398  DOI: 10.1142/S0217984920503984  Published: DEC 10 2020  

Abstract: Electron bombarded Active Pixel Sensor (EBAPS) is well known for its low noise in low-light level imaging, high mechanical integration, and a relatively low cost. It plays an important role in areas of the industrial process as well as the fundamental scientific research. However, the performance of EBAPS is intensively influenced by the structural parameters (i.e. the acceleration voltage between cathode and anode, thickness of the passivation layer, etc.). Due to the influence of these factors mentioned above, the performance of EBAPS is restricted to achieve its best condition. Herein, a model based on the optimized Monte Carlo method was proposed for effectively analyzing the scattering behavior of electrons within the electron multiplier layer. Unlike traditional simulation, which only deals with the electron scattering in longitudinal, in this paper, we simulate the electron scattering character not only in horizontal but also vertical among the multiplier layer, which would react to the influence induced by structural parameters more complete and more precise. Based on the proposed model, an experimental prototype of EBAPS is built and its detection sensitivity achieves 0.84 x 10(-4) lux under spectral response of ultraviolet (UV) spectroscopy, which improved a lot from our former design. The proposed model can be used for analyzing the influence induced by structural parameters, which exhibit enormous potential for exploring the high-gain EBAPS.

Accession Number: WOS:000599923700014

Author Identifiers:

ISSN: 0217-9849

eISSN: 1793-6640

Record 8 of 327

Title: Constraint analysis of measurement accuracy in high-precision X-ray pulsar positioning

Author(s): Yao, L (Yao, Li); Tong, S (Tong, Su); Mei, L (Mei, Luan); Zhang, FR (Zhang, Furui); Zhu, YC (Zhu, Yechuan); Yun, D (Yun, Du); Zhao, BS (Zhao, Baosheng)

Source: INTERNATIONAL JOURNAL OF MODERN PHYSICS B  Volume: 34  Issue: 30  Article Number: 2050296  DOI: 10.1142/S0217979220502963  Published: DEC 10 2020  

Abstract: In this paper, the relationship between direct measurement of X-ray pulsar angular position and second-order correlation is analyzed by classical statistical optics. On this basis, a scheme for measuring pulsar angle position is put forward on account of X-ray band intensity correlation, which is expected to achieve a positioning accuracy of 10 Mas. Finally, the connection between positioning accuracy and complex correlation in the intensity correlation measurement is studied. Also, main factors that affected the measurement are analyzed.

Accession Number: WOS:000599879800008

Author Identifiers:

ISSN: 0217-9792

eISSN: 1793-6578

Record 9 of 327

Title: A novel photochromic ceramics with reversible luminescence modulation and light bleaching behavior: Sm<SUP>3+</SUP>-doped KSr₂Nb₅O₁₅

Author(s): Cao, SY (Cao, Shuyao); Chen, Q (Chen, Qian); Liu, JT (Liu, Junting); Wu, CY (Wu, Changying); Li, LL (Li, Leilei); Xu, J (Xu, Jie); Cheng, GH (Cheng, Guanghua); Gao, F (Gao, Feng)

Source: JOURNAL OF THE EUROPEAN CERAMIC SOCIETY  Volume: 40  Issue: 15  Pages: 6061-6072  DOI: 10.1016/j.jeurceramsoc.2020.07.030  Published: DEC 2020  

Abstract: A novel tetragonal tungsten bronze (TTB) type Sm3+-doped KSr2Nb5O15 (KSN-Sm) optical ceramic is fabricated by atmosphere sintering technology. A reversible photochromic effect between faint yellow and olive colors and accompanied luminescence modulation behaviour can be realized by alternating the 395 nm light irradiation and thermal treatment. The thermal stimulus model is introduced to modify the classical resonance energy transfer mechanism. The results show that the optimal luminescence modulation ratio Delta R-t about the red emission (601 nm) intensity amounted to 60.0 %, and the KSN-Sm ceramic exhibits excellent luminescence modulation rate and reproducibility. The colored KSN-Sm ceramic can be partly bleached by external light stimulus (620 nm), and the luminescence emission intensity can be recovered from 45 % to 84.2 %. The light bleaching efficiency is strongly dependent on the irradiation wavelength, exposure duration and irradiation dose. These discoveries pave the way to develop new luminescence materials with TTB structure.

Accession Number: WOS:000564251000008

Author Identifiers:

ISSN: 0955-2219

eISSN: 1873-619X

Record 10 of 327

Title: Numerical investigation of radiation ablation and acceleration of high-density carbon foils

Author(s): Chen, P (Chen, Peng); Hu, RH (Hu, Ronghao); Zhou, H (Zhou, Hao); Tao, ZH (Tao, Zhihao); Gao, GL (Gao, Guilong); He, K (He, Kai); Wang, T (Wang, Tao); Tian, JS (Tian, Jinshou); Yi, T (Yi, Tao); Lv, M (Lv, Meng)

Source: LASER AND PARTICLE BEAMS  Volume: 38  Issue: 4  Pages: 239-243  Article Number: PII S0263034620000336  DOI: 10.1017/S0263034620000336  Published: DEC 2020  

Abstract: The ablation and acceleration of diamond-like high-density carbon foils irradiated by thermal X-ray radiations are investigated with radiation hydrodynamics simulations. The time-dependent front of the ablation wave is given numerically for radiation temperatures in the range of 100-300 eV. The mass ablation rates and ablation pressures can be derived or implied from the coordinates of ablation fronts, which agree well with reported experiment results of high-density carbon with radiation temperatures T-rad in the range of 160-260 eV. It is also found that the T-rad(3) scaling law for ablation rates does not apply to T-rad above 260 eV. The trajectories of targets and hydrodynamic efficiencies for different target thicknesses can be derived from the coordinates of ablation fronts using a rocket model and the results agree well with simulations. The peak hydrodynamic efficiencies of the acceleration process are investigated for different foil thicknesses and radiation temperatures. Higher radiation temperatures and target thicknesses result in higher hydrodynamic efficiencies. The simulation results are useful for the design of fusion capsules.

Accession Number: WOS:000600957600004

Author Identifiers:

ISSN: 0263-0346

eISSN: 1469-803X

Record 11 of 327

Title: High Photocurrent Density and Continuous Electron Emission Characterization of a Multi-Alkali Antimonide Photocathode

Author(s): Dai, J (Dai, Jun); Ding, YK (Ding, Yikun); Ruan, CJ (Ruan, Cunjun); Xu, XY (Xu, Xiangyan); Liu, HL (Liu, Hulin)

Source: ELECTRONICS  Volume: 9  Issue: 12  Article Number: 1991  DOI: 10.3390/electronics9121991  Published: DEC 2020  

Abstract: High photocurrent density cathodes that enable small cross-section electron beams are required for high-power terahertz vacuum devices. Multi-alkali antimonide photocathodes may be well suited for generating sub-mm electron beam sources. This paper involves the repeatability, stability, uniformity, and linearity experiments of the multi-alkali antimonide photocathodes electron emission operations under a continuous-wave 450 nm laser with a bias voltage of 5000 V. The effect of heat, electric contact, and cathode surface roughness to emission characterizations is analyzed. The methods to maintain the high-current-density emission and avoid the fatigue of the photocathode are verified. The emission can be repeated with increased optical power. The stable photocurrent density of near 1 A/cm(2) and maximum current density of near 1.43 A/cm(2) is recorded. The continuous photocurrent density is significantly improved compared to the current density reported in traditional applications. It is found that the current curves measuring at different areas of the photocathode differ greatly after the laser power of 800 mW. The increase in current for some areas may be attributed to the conductive current caused by built-in electric fields between the emission rough area and its adjacent areas.

Accession Number: WOS:000602078800001

Author Identifiers:

eISSN: 2079-9292

Record 12 of 327

Title: Optimized all-fiber laser Doppler velocimeter with large depth of field

Author(s): Hao, GY (Hao, GeYang); Cui, Y (Cui, Ying); Yang, YC (Yang, Yucheng); Iv, XP (Iv, Xiaopeng); Wu, GJ (Wu, Guojun)

Source: OPTICAL FIBER TECHNOLOGY  Volume: 60  Article Number: 102333  DOI: 10.1016/j.yofte.2020.102333  Published: DEC 2020  

Abstract: Due to the low spatial coupling efficiency of optical fiber and large energy loss, the depth of field in the all-fiber laser Doppler velocimeter is short, and the focus needs to be adjusted before measurement, so it is impossible to continuously measure the velocity of object moving along the optical axis. To solve this problem, an all-fiber Doppler velocimeter based on the Mach-Zehnder interferometer structure is designed, also, in the optical antenna section, C-lens is used to change the divergence angle of the light coming out of the optical fiber. The optimized design achieves the detection with large depth of field. The experiment is designed to verify the intensity of the echo signal, signal-to-noise ratio (SNR) and the speed accuracy of the velocimeter taken in different depths of field. The test results show that the depth of field in this system is superior to 25 m. The SNR is stable around 16 dB with small fluctuation in the range of depth of field, and the speed accuracy is better than +/- 0.1 m/s.

Accession Number: WOS:000598713600007

ISSN: 1068-5200

eISSN: 1095-9912

Record 13 of 327

Title: Highly accurate 3D reconstruction based on a precise and robust binocular camera calibration method

Author(s): Hu, GL (Hu, Guoliang); Zhou, ZF (Zhou, Zuofeng); Cao, JZ (Cao, Jianzhong); Huang, HM (Huang, Huimin)

Source: IET IMAGE PROCESSING  Volume: 14  Issue: 14  Pages: 3588-3595  DOI: 10.1049/iet-ipr.2019.1525  Published: DEC 2020  

Abstract: The precision of the camera calibration is one of the key factors that affect attitude measurement accuracy in many computer vision tasks. This study proposes a new calibration approach for binocular cameras. Firstly, based on singular value decomposition, the best transformation matrix to the essential matrix is approximated as the initial guess, which is solved in using the Frobenius norm. Secondly, the initial guess is refined through maximum likelihood estimation. A new calculating expression is derived for computing the relative position matrix of the binocular cameras. The Levenberg-Marquardt algorithm is then implemented to refine the initial guess. Large sets of synthesised and real point correspondences were tested to demonstrate the validity of the proposed method. Extensive experiments demonstrated that the proposed method outperforms the state-of-the-art methods. The error rate of the proposed method was 0.5% for the length test and about 1% for the angle test at a range of 1 m. This method can advance three-dimensional (3D) computer vision one additional step from laboratory environments to real-world use.

Accession Number: WOS:000605364800031

ISSN: 1751-9659

eISSN: 1751-9667

Record 14 of 327

Title: High power, tunable, ultra-narrowband Yb-doped superfluorescent fiber source operating at wavelength less than 1055 nm with 20 nm tuning range

Author(s): Ju, P (Ju, Pei); Fan, WH (Fan, Wenhui); Zhao, BY (Zhao, Baoyin); Gao, W (Gao, Wei); Zhang, TY (Zhang, Tongyi); Li, G (Li, Gang); Gao, Q (Gao, Qi); Li, Z (Li, Zhe)

Source: INFRARED PHYSICS & TECHNOLOGY  Volume: 111  Article Number: 103530  DOI: 10.1016/j.infrared.2020.103530  Published: DEC 2020  

Abstract: Tunable, narrowband superfluorescent fiber sources (SFSs) are significantly important for spectral combination. Here, we propose a high power, tunable, ultra-narrowband Yb-doped SFS operating at wavelength less than 1055 nm with 20 nm tuning range. The system is composed of a broadband SFS, a home-mode space-to-fiber tunable spectral filter, and a three-stage amplifier chain. In order to achieve three typical characteristics, namely, operating in the shorter wavelength region (SWR) with wide spectrum, tunable and narrowband, and high-power output, the performance of the system is investigated and optimized based on the rate equations with temperature, grating monochromator and the coupling theory of Gaussian beam between fibers. Theoretical investigation indicates that a broadband SFS operating in the SWR with wide spectrum can be achieved by controlling temperature within a certain range. Moreover, by optimizing space-to-fiber tunable spectral filter, the tunable, ultra-narrowband SFS with linewidth of 0.088 nm can be obtained. In addition, the seed laser with signal to noise ratio (SNR) of more than 30 dB and the appropriate length of active fiber can gain better amplification performance from the main amplifier. Based on these optimized parameters, a high power, tunable, ultra-narrowband Yb-doped SFS has been built experimentally. The output power of narrowband SFS operating in tunable range from 1035 nm to 1055 nm exceeds 300 W with M-2 factor of 1.47, and the measured full width at half maximum and SNR of which are less than 0.1 nm and beyond 30 dB, respectively. This work extends the spectral region and capacity of narrowband SFSs, and will be useful for further power scaling of spectral beam combination.Y

Accession Number: WOS:000599507400005

Author Identifiers:

ISSN: 1350-4495

eISSN: 1879-0275

Record 15 of 327

Title: Lasercom optical-terminal performance testing platform

Author(s): Li, J (Li, Jing); Xue, X (Xue, Xun); Wang, ZF (Wang, Zhengfeng); Liu, K (Liu, Kai); Zhou, Y (Zhou, Yan); Zhao, JK (Zhao, Jianke)

Source: OPTIK  Volume: 224  Article Number: 165521  DOI: 10.1016/j.ijleo.2020.165521  Published: DEC 2020  

Abstract: The lasercom optical-terminal performance testing platform (LCOT-PTP) is a precision optical system providing experimental testing of important characteristic parameters including transmitting power, beam divergence angle, far-field spot energy distribution and coaxialities of different branches in a lasercom optical terminal (LCOT). The LCOT-PTP consisting of a telescope, beam splitters, a receiving branch, a transmitting branch and a tracking test branch is developed. Due to the testing process requirements in coarse tracking, fine tracking and the assembly integration, the working wavelengths of 808nm, 1550nm and 632.8nm are adopted in testing-system design. By using the under-test LCOT parameters and Gaussian beam transmitting theory, the optical-system design is completed. Based on the established LCOT-PTP, the key performance testing work is accomplished.

Accession Number: WOS:000599257500008

Author Identifiers:

ISSN: 0030-4026

eISSN: 1618-1336

Record 16 of 327

Title: Optimization and Experiment of a Novel Compliant Focusing Mechanism for Space Remote Sensor

Author(s): Li, Y (Li, Yan); Ge, WJ (Ge, Wenjie); Zhang, X (Zhang, Xu); Tong, XX (Tong, Xinxing)

Source: SENSORS  Volume: 20  Issue: 23  Article Number: 6826  DOI: 10.3390/s20236826  Published: DEC 2020  

Abstract: The change of an external environment leads to the defocusing phenomenon of the space optical remote sensor. The performance of the focusing mechanism is related to the image quality of the remote sensor. It was optimized for a novel focusing mechanism comprised of a flexural hinge lever-type amplifier and several piezoelectric ceramics to improve the performance on high loads and large stroke in this research. It has advantages of a lightweight, simple structure and high reliability compared with the traditional focusing mechanism. The input displacement from the piezoelectric actuators was amplified by a two-stage flexure hinge lever-type mechanism. Dimensional parameters of the flexural hinges were considered as design variables. Based on the optimization ideology, reasonable compliance and dimension parameters of the flexural hinges were analyzed for the focusing mechanism. Simulation and experiments of deformation were conducted to validate the correctness of design optimization. The results show that the focusing mechanism designed by the proposed method has the capabilities of an amplification ratio of 100 times and a loading carrying capacity of 2 kg. This work provides a novel strategy to design an excellent focusing mechanism with lightweight, high loads and large stroke. Moreover, it is believed that this approach can be extended to other complex sensors.

Accession Number: WOS:000597916300001

PubMed ID: 33260361

eISSN: 1424-8220

Record 17 of 327

Title: Using Cherenkov imaging to monitor the match line between photon and electron radiation therapy fields on biological tissue phantoms

Author(s): Li, Y (Li, Yi); Liu, HJ (Liu, Hongjun); Huang, N (Huang, Nan); Wang, ZL (Wang, Zhaolu); Zhang, CM (Zhang, Chunmin)

Source: JOURNAL OF BIOMEDICAL OPTICS  Volume: 25  Issue: 12  Article Number: 125001  DOI: 10.1117/1.JBO.25.12.125001  Published: DEC 2020  

Abstract: Significance: Due to patients' respiratory movement or involuntary body movements during breast cancer radiotherapy, the mismatched adjacent fields in surface exposure regions could result in insufficient dosage or overdose in these regions, which would lead to tissue injury, excessive skin burns, and potential death. Cherenkov luminescence imaging (CLI) could be used to effectively detect the matching information of adjacent radiation fields without extra radiation or invasive imaging.
Aim: Our objective was to provide a biological experimental basis for monitoring matching of adjacent radiation fields between photon and electron fields due to introduced shifts during radiotherapy by CLI technique.
Approach: A medical accelerator was used to generate photon and electron fields. An industrial camera system was adopted to image the excited CLI signal during irradiation of chicken tissue with yellow (group A and group C experiments) or black color (group B experiment). The following introduced shifts were tested: 10, 5, 2, and 0 mm toward superior or inferior direction. A model was introduced to deal with matching error analysis of adjacent radiation fields due to introduced shifts with adapted plans used to treat neoplasms of the right breast with supraclavicular nodes or internal mammary lymph node.
Results: The matching values between photon and electron fields were consistent with the tested introduced shifts during yellow chicken irradiation. In group A, average discrepancies were 0.59 +/- 0.35 mm and 0.68 +/- 0.37 mm for photon fields and electron fields in anterior/posterior (AP) direction, with 87% and 75% of measurement within 1 mm, respectively. In group C, average discrepancies were 0.80 +/- 0.65 mm and 1.07 +/- 0.57 mm for oblique photon field with gantry angles of 330 deg and 150 deg, with 66% and 65% of measurement within 1 mm, respectively. The average discrepancies were 0.44 +/- 0.30 mm for electron field in the AP direction, with 94% of measurement within 1 mm. The matching error introduced by the proposed method was less than 1.5 mm for AP fields and 2 mm for oblique incidence fields. However, the field matching could not be monitored with black chicken tissue irradiation due to a weak CLI signal that could hardly be extracted from background noise in group B.
Conclusions: CLI is demonstrated for the quantitative monitoring of the field match line on light biological tissue phantoms and has potential for monitoring of field matching in surface tissue during breast cancer radiotherapy. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.

Accession Number: WOS:000605144900009

PubMed ID: 33300317

Author Identifiers:

ISSN: 1083-3668

eISSN: 1560-2281

Record 18 of 327

Title: Measurement of moisture content in lubricating oils of high-speed rail gearbox by Vis-NIR spectroscopy

Author(s): Liu, CY (Liu, Chenyang); Tang, XJ (Tang, Xingjia); Yu, T (Yu, Tao); Wang, TS (Wang, Taisheng); Lu, ZW (Lu, Zhenwu); Yu, WX (Yu, Weixing)

Source: OPTIK  Volume: 224  Article Number: 165694  DOI: 10.1016/j.ijleo.2020.165694  Published: DEC 2020  

Abstract: The moisture content in lubricating oil is one of the most important factors to reflect the health and effectiveness of it, thus to monitor the moisture content in lubricating oil in real time is crucial for high speed rail. In this paper, we developed a compact moisture-content monitoring system based on the visible-near-infrared (Vis-NIR) spectroscopy technology, which was shown to be able to determine the moisture content in lubricating oil in a fast, simple and accurate way. In this system, a reflection mode optical probe was developed for sending and receiving optical signals through the viewport of gear box. By employing the reflection optical probe, one can measure the spectrum of the lubricating oil in a fast way by simply putting the probe on viewport of gear box, and therefore has the potential to realize the real-time monitoring of the status of the lubricating oil. In order to verify the feasibility of the system, both reflection and transmission spectral of lubricating oil were taken. Partial least square regression (PLS) and back propagation neural network (BPNN) algorithms were used to establish the processing model. Modelling results show a good agreement in between two different probing modes. As a result, the effectiveness and reliability of the system have been proved, which provides a simple yet accurate method for real time monitoring the healthy status of the lubricating oil for the safe operation of the high-speed rail.

Accession Number: WOS:000596850700011

Author Identifiers:

ISSN: 0030-4026

eISSN: 1618-1336

Record 19 of 327

Title: Photonic crystal rod-based high-performance ultrafast fiber laser system

Author(s): Lv, ZG (Lv, Zhiguo); Yang, Z (Yang, Zhi); Li, QL (Li, Qianglong); Li, F (Li, Feng); Wang, YS (Wang, Yishan); Zhao, W (Zhao, Wei); Yang, XJ (Yang, Xiaojun)

Source: HIGH POWER LASER SCIENCE AND ENGINEERING  Volume: 8  Article Number: e40  DOI: 10.1017/hpl.2020.42  Published: DEC 1 2020  

Abstract: In this paper, we innovatively conduct a Porro prism-based beam pointing stability promotion technique research and realize a high-performance rod-type photonic crystal fiber-based chirped pulse amplification (CPA) system, mainly including a frequency-reduced all-fiber pre-amplification stage, photonic crystal rod-based main amplification stage, and 1600 lines/mm transmission grating-pair compressor. Laser output with average power of 50 W, repetition rates of 500 kHz, pulse energy of 100 mu J, pulse duration of 830 fs, beam quality of M-2<1.3, power fluctuation of 0.55% root mean square, and beam pointing drift of 19 mu rad/degrees C over 8 h is realized. The high-performance laser system has an enormous application potential in fundamental research and precision manufacturing fields.

Accession Number: WOS:000596505800001

Author Identifiers:

ISSN: 2095-4719

eISSN: 2052-3289

Record 20 of 327

Title: Nonlocal Graph Convolutional Networks for Hyperspectral Image Classification

Author(s): Mou, LC (Mou, Lichao); Lu, XQ (Lu, Xiaoqiang); Li, XL (Li, Xuelong); Zhu, XX (Zhu, Xiao Xiang)

Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING  Volume: 58  Issue: 12  Pages: 8246-8257  DOI: 10.1109/TGRS.2020.2973363  Published: DEC 2020  

Abstract: Over the past few years making use of deep networks, including convolutional neural networks (CNNs) and recurrent neural networks (RNNs), classifying hyperspectral images has progressed significantly and gained increasing attention. In spite of being successful, these networks need an adequate supply of labeled training instances for supervised learning, which, however, is quite costly to collect. On the other hand, unlabeled data can be accessed in almost arbitrary amounts. Hence it would be conceptually of great interest to explore networks that are able to exploit labeled and unlabeled data simultaneously for hyperspectral image classification. In this article, we propose a novel graph-based semisupervised network called nonlocal graph convolutional network (nonlocal GCN). Unlike existing CNNs and RNNs that receive pixels or patches of a hyperspectral image as inputs, this network takes the whole image (including both labeled and unlabeled data) in. More specifically, a nonlocal graph is first calculated. Given this graph representation, a couple of graph convolutional layers are used to extract features. Finally, the semisupervised learning of the network is done by using a cross-entropy error over all labeled instances. Note that the nonlocal GCN is end-to-end trainable. We demonstrate in extensive experiments that compared with state-of-the-art spectral classifiers and spectral-spatial classification networks, the nonlocal GCN is able to offer competitive results and high-quality classification maps (with fine boundaries and without noisy scattered points of misclassification).

Accession Number: WOS:000594389800001

Author Identifiers:

ISSN: 0196-2892

eISSN: 1558-0644

Record 21 of 327

Title: Azimuthally phase-shifted Fibonacci zone plate

Author(s): Rafighdoost, J (Rafighdoost, Jila); Zhou, Y (Zhou, Yuan); Li, X (Li, Xing); Yan, SH (Yan, Shaohui); Zhou, ML (Zhou, Meiling); Yao, BL (Yao, Baoli)

Source: JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS  Volume: 37  Issue: 12  Pages: 3557-3563  DOI: 10.1364/JOSAB.402866  Published: DEC 1 2020  

Abstract: We present a novel and straightforward Fibonacci lens, which is created by binarizing and adding a spiral phase to its radial phase function. It is shown that this new element yields a pair of petal-like modes due to several segments of the Fibonacci lens, where each segment is phase shifted by pi compared to its adjacent segment. Also, the generated petals have highly controllable rotation, and their locations are adjustable, in which their focal distance ratio is equal to a mathematical parameter of the so-called golden ratio. Also, by changing the topological charge, an arbitrary even number of petals is obtained. (C) 2020 Optical Society of America

Accession Number: WOS:000595619400002

Author Identifiers:

ISSN: 0740-3224

eISSN: 1520-8540

Record 22 of 327

Title: A novel color calibration method of multi-spectral camera based on normalized RGB color model

Author(s): Wang, H (Wang, Hong); Yang, JF (Yang, Jianfeng); Xue, B (Xue, Bin); Yan, XT (Yan, Xingtao); Tao, JY (Tao, Jinyou)

Source: RESULTS IN PHYSICS  Volume: 19  Article Number: 103498  DOI: 10.1016/j.rinp.2020.103498  Published: DEC 2020  

Abstract: True-color image of Mars is important for mineral analysis. The working light source of the Mars exploration multi-spectral camera is different from the laboratory calibration light source, so that the commonly used RGB calibration method has a large color difference in correcting the on-orbit images. After analyzing the influence of light source lightness and relative spectral distribution on the camera output values, their influences are considered separately in the calibration. A new color calibration method in the luminance-independent chromaticity space is proposed. The RGB color components of multi-spectral camera are normalized and converted to chromaticity values, and the polynomial calibration model in chromaticity space is compared with the RGB method. The experimental results showed that the average value of CIE DE2000 color differences after color calibration was 4.32, which was 0.96 less than that of RGB method. When the calibration matrix was used to correct the outdoor scene images, the corrected color difference gain because of the change of imaging light source was reduced by 0.54 compared to the RGB method. The color calibration method and the calibration data in this paper provide theoretical support for the color correction of the Mars multi-spectral camera on-orbit images.

Accession Number: WOS:000604225100006

Author Identifiers:

ISSN: 2211-3797

Record 23 of 327

Title: Long-distance ranging with high precision using a soliton microcomb

Author(s): Wang, JD (Wang, Jindong); Lu, ZZ (Lu, Zhizhou); Wang, WQ (Wang, Weiqiang); Zhang, FM (Zhang, Fumin); Chen, JW (Chen, Jiawei); Wang, Y (Wang, Yang); Zheng, JH (Zheng, Jihui); Chu, ST (Chu, Sai T.); Zhao, W (Zhao, Wei); Little, BE (Little, Brent E.); Qu, XH (Qu, Xinghua); Zhang, WF (Zhang, Wenfu)

Source: PHOTONICS RESEARCH  Volume: 8  Issue: 12  Pages: 1964-1972  DOI: 10.1364/PRJ.408923  Published: DEC 1 2020  

Abstract: Laser-based light detection and ranging (lidar) plays a significant role in both scientific and industrial areas. However, it is difficult for existing lidars to achieve high speed, high precision, and long distance simultaneously. Here, we demonstrate a high-performance lidar based on a chip-scaled soliton microcomb (SMC) that can realize all three specialties simultaneously. Aided by the excellent properties of ultrahigh repetition rate and the smooth envelope of the SMC, traditional optical frequency comb (OFC)-based dispersive interferometry is heavily improved and the measuring dead zone induced by the mismatch between the repetition rate of the OFC and resolution of the optical spectrum analyzer is totally eliminated. Combined with an auxiliary dual-frequency phase-modulated laser range finder, the none-dead-zone measurable range ambiguity is extended up to 1500 m. The proposed SMC lidar is experimentally implemented in both indoor and outdoor environment. In the outdoor baseline field, real-time, high-speed (up to 35 kHz) measurement of a long distance of similar to 1179 m is achieved with a minimum Allan deviation of 5.6 mu m at an average time of 0.2 ms (27 nm at an average time of 1.8 s after high-pass filtering). The present SMC lidar approaches a compact, fast, high-precision, and none-dead zone long-distance ranging system, aimed at emerging applications of frontier basic scientific research and advances in industrial manufacturing. (C) 2020 Chinese Laser Press

Accession Number: WOS:000595832200020

Author Identifiers:

ISSN: 2327-9125

Record 24 of 327

Title: A Method for Improving the Detection Accuracy of the Spot Position of the Four-Quadrant Detector in a Free Space Optical Communication System

Author(s): Wang, X (Wang, Xuan); Su, XQ (Su, Xiuqin); Liu, GZ (Liu, Guizhong); Han, JF (Han, Junfeng); Wang, KD (Wang, Kaidi); Zhu, WH (Zhu, Wenhua)

Source: SENSORS  Volume: 20  Issue: 24  Article Number: 7164  DOI: 10.3390/s20247164  Published: DEC 2020  

Abstract: In a free space optical communication system, the beacon light will lose most of its energy after long-distance transmission, and the background light from the universe will strongly interfere with it. The four-quadrant detector (4QD) has been widely used in optical communication systems as a high-precision spot position detection sensor. However, if the light signal falling on the 4QD is too weak, the electrical signal of the output position will be very weak, and it will easily be affected by or even submerged in noise. To solve this problem, we propose a method for improving the spot position detection accuracy. First, we analyzed the solution relationship between the actual position of the spot and the output signal of the 4QD, with a Gaussian spot as the incident light model. The output current signal of the detector was then transimpedance-amplified by an analog circuit and the output voltage signal with noise was digitally filtered. An error compensation factor and the gap size of the detector were introduced into the traditional spot position detection model. High-precision spot position information for the 4QD in a complex environment was then obtained using the improved spot position detection model. Experimental results show that the maximum spot position detection error for this method was only 0.0277 mm, and the root mean square error was 0.0065 mm, when the 4QD was in a high background noise environment. The spot position detection accuracy was significantly improved compared with traditional detection algorithms. Real-time detection can therefore be achieved in practical applications.

Accession Number: WOS:000603200300001

PubMed ID: 33327521

Author Identifiers:

eISSN: 1424-8220

Record 25 of 327

Title: W-shaped common-path interferometer

Author(s): Wei, RY (Wei, Ruyi); Di, LM (Di, Lamei); Qiao, NZ (Qiao, Nianzu); Chen, SS (Chen, Shasha)

Source: APPLIED OPTICS  Volume: 59  Issue: 34  Pages: 10973-10979  DOI: 10.1364/AO.411150  Published: DEC 1 2020  

Abstract: We present a novel static W-shaped common-path interferometer. In particular, the W-shaped common-path corner-cube retroreflector interferometer (W-CPRI) is introduced via detailed analysis of its working principles and performance. It comprises two corner-cube retroreflectors (CCRs), a reflecting mirror (RM), and a beam splitter. For each interference output of an ideal W-CPRI, the two beams recombine and have the same output direction, including a tilted CCR. In a deformed W-CPRI structure, an optical path difference can be produced by inserting an optical element that changes the optical path in the interferometer arm of the W-CPRI. The posture deviations of the RM and the CCRs in the W-CPRI are analyzed. In addition, a proof-of-concept experiment is conducted, with the stability analyzed using the fringe similarity method. The average cosine similarity is 0.9953, revealing that this W-CPRI has high stability and strong coherence while avoiding the tilt and displacement of the interferometer arm. (C) 2020 Optical Society of America

Accession Number: WOS:000595631500042

PubMed ID: 33361920

Author Identifiers:

ISSN: 1559-128X

eISSN: 2155-3165

Record 26 of 327

Title: Photonic RF and Microwave Integrator Based on a Transversal Filter With Soliton Crystal Microcombs

Author(s): Xu, XY (Xu, Xingyuan); Tan, MX (Tan, Mengxi); Wu, JY (Wu, Jiayang); Boes, A (Boes, Andreas); Corcoran, B (Corcoran, Bill); Nguyen, TG (Nguyen, Thach G.); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Morandotti, R (Morandotti, Roberto); Mitchell, A (Mitchell, Arnan); Moss, DJ (Moss, David J.)

Source: IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS  Volume: 67  Issue: 12  Pages: 3582-3586  DOI: 10.1109/TCSII.2020.2995682  Published: DEC 2020  

Abstract: We demonstrate a photonic RF integrator based on an integrated soliton crystal micro-comb source. By multicasting and progressively delaying the input RF signal using a transversal structure, the input RF signal is integrated discretely. Up to 81 wavelengths are provided by the microcomb source, which enable a large time-bandwidth product of 81. Our approach also features a high degree of reconfigurability. By simply adjusting the value of dispersion (i.e., the length of dispersive fibre), the integration time window and resolution can be reconfigured to accommodate a diverse range of applications. We employed 13 km of standard single-mode fibre to achieve a large integration time window of similar to 6.8 ns, a time resolution as fast as similar to 84 ps, with a broad bandwidth of 11.9 GHz. In addition, we perform signal integration of a diverse range of input RF signals including Gaussian pulses with varying time widths, dual pulses with varying time intervals and a square waveform. The experimental results show good agreement with theory. These results verify our microcomb-based integrator as a competitive approach for RF signal integration with high performance and potentially lower cost and footprint.

Accession Number: WOS:000594648600155

Author Identifiers:

ISSN: 1549-7747

eISSN: 1558-3791

Record 27 of 327

Title: Accelerating triangle-like singular beam

Author(s): Yan, SH (Yan, Shaohui); Li, MM (Li, Manman); Zhou, Y (Zhou, Yuan); Zhang, YA (Zhang, Yanan); Yao, BL (Yao, Baoli)

Source: JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION  Volume: 37  Issue: 12  Pages: 1965-1970  DOI: 10.1364/JOSAA.408431  Published: DEC 1 2020  

Abstract: We demonstrate a type of singular beam that accelerates along a parabolic trajectory and has a cross-section intensity pattern exhibiting a dark central region surrounded by multiple rings with the innermost (main) ring resembling an equilateral triangle. The key to creating such beams is to replace the standard triangle with a rounded one, made up of six circular arcs connected end to end. The individual input phase mask for each arc can be analytically computed, and the whole input phase mask for the beam is thus obtained by piecing together these individual phases. Furthermore, the continuity of field forces of these triangle-like modes is discrete; that is, an index similar to the topological charge of vortex beams arises. Numerical results show that the energy flow in the beam's cross section circulates around the dark center along the triangle-like main ring, suggesting a possible application in orbiting particles along an irregular path. (C) 2020 Optical Society of America.

Accession Number: WOS:000596504300005

PubMed ID: 33362140

Author Identifiers:

ISSN: 1084-7529

eISSN: 1520-8532

Record 28 of 327

Title: Attribute-Cooperated Convolutional Neural Network for Remote Sensing Image Classification

Author(s): Zhang, YL (Zhang, Yuanlin); Zheng, XT (Zheng, Xiangtao); Yuan, Y (Yuan, Yuan); Lu, XQ (Lu, Xiaoqiang)

Source: IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING  Volume: 58  Issue: 12  Pages: 8358-8371  DOI: 10.1109/TGRS.2020.2987338  Published: DEC 2020  

Abstract: Remote sensing image (RSI) classification is one of the most important fields in RSI processing. It is well known that RSIs are very complicated due to its various kinds of contents. Therefore, it is very difficult to distinguish different scene categories with similar visual contents, like desert and bare land. To address hard negative categories, an attribute-cooperated convolutional neural network (ACCNN) is proposed to exploit attributes as additional guiding information. First, the classification branch extracts convolutional neural network feature, which is then utilized to recognize the RSI scene categories. Second, the attribute branch is proposed to make the network distinguish scene categories efficiently. The proposed attribute branch shares feature extraction layers with the classification branch and makes the classification branch aware of extra attribute information. Finally, the relationship branch constraints the relationship between the classification branch and the attribute branch. To exploit the attribute information, three attribute-classification data sets are generated (AC-AID, AC-UCM, and AC-Sydney). Experimental results show that the proposed method is competitive to state-of-the-art methods. The data sets are available at https://github.com/CrazyStoneonRoad/Attribute-Cooperated-Classification-Data sets.

Accession Number: WOS:000594389800009

Author Identifiers:

ISSN: 0196-2892

eISSN: 1558-0644

Record 29 of 327

Title: Generation of a noise-like pulse from an erbium-doped fiber laser based on nonlinear multimode interference

Author(s): Zhao, FY (Zhao, Fengyan); Li, N (Li, Ning); Wang, HS (Wang, Hushan)

Source: LASER PHYSICS  Volume: 30  Issue: 12  Article Number: 125102  DOI: 10.1088/1555-6611/abc06d  Published: DEC 2020  

Abstract: A noise-like pulse (NLP) is generated in an anomalous-dispersion passively mode-locked erbium-doped fiber laser using graded-index multimode fiber (GIMF) as the all-fiber saturable absorber (SA) for the first time. By splicing two sections of bending GIMF at both ends of a single mode fiber and optimizing the birefringence and nonlinear parameters, stable NLP mode-locking operation can be achieved within a wide pump power range. Meanwhile, the performances of NLP mode-locking have been analyzed experimentally by changing the length of the GIMF.

Accession Number: WOS:000590131900001

Author Identifiers:

ISSN: 1054-660X

eISSN: 1555-6611

Record 30 of 327

Title: Physical and Mechanical Characteristics of Lunar Soil at the Chang'E-4 Landing Site

Author(s): Tang, ZC (Tang, Zhencheng); Liu, JJ (Liu, Jianjun); Wang, X (Wang, Xing); Ren, X (Ren, Xin); Chen, WL (Chen, Wangli); Yan, W (Yan, Wei); Zhang, XX (Zhang, Xiaoxia); Tan, X (Tan, Xu); Zeng, XG (Zeng, Xingguo); Liu, DW (Liu, Dawei); Zhang, HB (Zhang, Hongbo); Wen, WB (Wen, Weibin); Zuo, W (Zuo, Wei); Su, Y (Su, Yan); Yang, JF (Yang, Jianfeng); Li, CL (Li, Chunlai)

Source: GEOPHYSICAL RESEARCH LETTERS  Volume: 47  Issue: 22  Article Number: e2020GL089499  DOI: 10.1029/2020GL089499  Published: NOV 28 2020  

Abstract: Chang'E-4, with the Yutu-2 rover, is the first lunar probe to successfully land and conduct a tour on the far side of the Moon from early 2019. We analyze the physical and mechanical characteristics of lunar soil through the in situ terrain data collected by the panoramic camera onboard the Yutu-2 rover. With the slip ratio and wheel sinkage obtained by the derived Digital Orthophoto Map (DOM) and Digital Elevation Model (DEM), the mechanical parameters of lunar soil are derived from the slip-sinkage model. These mechanical parameters and wheel size of the rover are used to obtain the pressure-sinkage curves, which can estimate the lunar soil strength. The experimental results indicate that the soil strength at the Chang'E-4 landing site is much higher than that at the Chang'E-3 landing site. The discrepancies in lunar soil strength between the two landing sites may be related to the local surface topography and degree of space weathering.
Plain Language Summary The knowledge of the physical and mechanical characteristics of lunar soil is of fundamental importance because it is the basis for mineral resource exploration and engineering activity aimed at the construction of lunar bases. The Chang'E-4 landing site is within the mare floor of the Von Karman crater inside the South Pole-Aitken (SPA) basin. The ejecta from the nearby impact craters has covered the Chang'E-4 landing area. Besides, the lunar soil of the Chang'E-4 landing area has been relatively mature. Here, a method of analyzing the characteristics of lunar soil is introduced to provide an opportunity to understand the physical and mechanical properties of the mature lunar soil at the Chang'E-4 landing site. With the terrain data collected by the panoramic camera onboard the Yutu-2 rover, we can get the relationship curve of the interaction between the rover wheels and lunar soil, such as the pressure-sinkage curve. The pressure-sinkage curves can intuitively reflect the discrepancies of lunar soil strength at the Chang'E-4 and Chang'E-3 landing sites, which may bear a big relationship to the local surface morphology and degree of space weathering.

Accession Number: WOS:000595819700097

Author Identifiers:

ISSN: 0094-8276

eISSN: 1944-8007

Record 31 of 327

Title: All-fiber phase modulator and switch based on local surface plasmon resonance effect of the gold nanoparticles embedded in gel membrane

Author(s): Luo, M (Luo, Meng); Yang, XH (Yang, Xinghua); Teng, PP (Teng, Pingping); Liu, ZH (Liu, Zhihai); Yang, J (Yang, Jun); Kong, DP (Kong, Depeng); Gao, DH (Gao, Danheng); Li, ZN (Li, Zhanao); Wen, XY (Wen, Xingyue); Yu, XM (Yu, Ximiao); Yuan, LB (Yuan, Libo); Li, K (Li, Kang); Bowkett, M (Bowkett, Mark); Copner, N (Copner, Nigel); Wang, XZ (Wang, Xiaozhang)

Source: APPLIED OPTICS  Volume: 59  Issue: 33  Pages: 10506-10511  DOI: 10.1364/AO.406268  Published: NOV 20 2020  

Abstract: All-fiber modulators and switches have drawn great interest in the photonics domain, and they are applied in viable photonic and optoelectronic devices. In this work, with the assistance of an agarose membrane, aspherical gold nanoparticles are embedded on the surface of the microfiber treated with the piranha solution. An all-fiber Mach-Zehnder interferometer was used to realize a low-cost, low-loss, and conveniently prepared all-fiber phase modulator. By taking advantage of the local surface plasmon resonance effect of gold nanoparticles embedded in the agarose membrane, under the excitation of near-infrared region light, the gold nanoparticles were excited to change the effective refractive index of one arm of the Mach-Zehnder interferometer. A maximum phase shift of similar to 6 pi at 1550 nm was obtained from the device. In addition, an all-optical switch was achieved with a rising edge time of47 ms and falling edge time of 14 ms. The proposed all-fiber modulator and switch based on the local surface plasmon resonance effect of gold nanoparticles embedded in agarose membrane will provide great potential in all-optical fiber systems. (C) 2020 Optical Society of America

Accession Number: WOS:000592671500038

PubMed ID: 33361985

Author Identifiers:

ISSN: 1559-128X

eISSN: 2155-3165

Record 32 of 327

Title: Cascaded few-mode fiber down-taper modal interferometers and their application in curvature sensing

Author(s): Chen, EQ (Chen, Enqing); Dong, B (Dong, Bo); Li, Y (Li, Yang); Wang, XL (Wang, Xiaoli); Zhao, YD (Zhao, Yudi); Xu, W (Xu, Wei); Zhao, W (Zhao, Wei); Wang, YS (Wang, Yishan)

Source: OPTICS COMMUNICATIONS  Volume: 475  Article Number: 126274  DOI: 10.1016/j.optcom.2020.126274  Published: NOV 15 2020  

Abstract: Few-mode fiber modal interferometers (MIs) based on cascaded fiber down-tapers and their application in curvature sensing are presented. Cascaded fiber down-taper structure can help excite more higher-order cladding modes to construct the inter-modal interference with the core mode. However, with the increase of the cascaded number of the fiber down-tapers, the curvature sensitivity of the MI is decreased accordingly. This provides a new way to control the curvature sensitivity of such device by cascading fiber down-tapers. Experimental results show that compared with the two down-tapers based MI, the curvature sensitivity of the three down-tapers one reduced by 1.64 times while the four down-tapers one reduced by 5.82 times.

Accession Number: WOS:000563999700017

ISSN: 0030-4018

eISSN: 1873-0310

Record 33 of 327

Title: Breathing process monitoring with a biaxially oriented polypropylene film based fiber Fabry-Perot sensor

Author(s): Li, Y (Li, Yang); Dong, B (Dong, Bo); Chen, EQ (Chen, Enqing); Wang, XL (Wang, Xiaoli); Zhao, YD (Zhao, Yudi); Zhao, W (Zhao, Wei); Wang, YS (Wang, Yishan)

Source: OPTICS COMMUNICATIONS  Volume: 475  Article Number: 126292  DOI: 10.1016/j.optcom.2020.126292  Published: NOV 15 2020  

Abstract: The breathing process monitoring with a biaxially oriented polypropylene (BOPP) film based fiber Fabry-Perot (F-P) sensor is presented. The fiber F-P sensor is fabricated with 3-D printing technology and fixed on a medical respirator for breathing process monitoring. Due to the low Young's modulus of the BOPP film and its thinner thickness, the breathing sensor shows the high pressure sensitivity of-0.581 nm/Pa. By monitoring its intensity response to the pressure induced by breathing, the breathing process can be monitored accurately, including respiratory waveform, respiratory rate, inspiratory duration and amplitude, expiratory duration and amplitude, and inspiratory and expiratory rhythm. Since the sensor is all fiber design with the inherent advantages of small size, anti-electromagnetic interference, green environmental protection, pollution-free and no harm to body, it is expected to be widely used in respiratory disease monitoring.

Accession Number: WOS:000563999900009

Author Identifiers:

ISSN: 0030-4018

eISSN: 1873-0310

Record 34 of 327

Title: Photonic RF Arbitrary Waveform Generator Based on a Soliton Crystal Micro-Comb Source

Author(s): Tan, MX (Tan, Mengxi); Xu, XY (Xu, Xingyuan); Boes, A (Boes, Andreas); Corcoran, B (Corcoran, Bill); Wu, JY (Wu, Jiayang); Nguyen, TG (Nguyen, Thach G.); Chu, ST (Chu, Sai T.); Little, BE (Little, Brent E.); Morandotti, R (Morandotti, Roberto); Mitchell, A (Mitchell, Arnan); Moss, DJ (Moss, David J.)

Source: JOURNAL OF LIGHTWAVE TECHNOLOGY  Volume: 38  Issue: 22  Pages: 6221-6226  DOI: 10.1109/JLT.2020.3009655  Published: NOV 15 2020  

Abstract: We report a photonic-based radio frequency (RF) arbitrary waveform generator (AWG) using a soliton crystal micro-comb source with a free spectral range (FSR) of 48.9 GHz. The comb source provides over 80 wavelengths, or channels, that we use to successfully achieve arbitrary waveform shapes including square waveforms with a tunable duty ratio ranging from 10% to 90%, sawtooth waveforms with a tunable slope ratio of 0.2 to 1, and a symmetric concave quadratic chirp waveform with an instantaneous frequency of sub GHz. We achieve good agreement between theory and experiment, validating the effectiveness of this approach towards realizing high-performance, broad bandwidth, nearly user-defined RF waveform generation.

Accession Number: WOS:000583494400009

Author Identifiers:

ISSN: 0733-8724

eISSN: 1558-2213

Record 35 of 327

Title: Improved genetic algorithm for intrinsic parameters estimation of on-orbit space cameras

Author(s): Zhang, GP (Zhang, Gaopeng); Zhao, H (Zhao, Hong); Zhang, GD (Zhang, Guangdong); Chen, YH (Chen, Yaohong)

Source: OPTICS COMMUNICATIONS  Volume: 475  Article Number: 126235  DOI: 10.1016/j.optcom.2020.126235  Published: NOV 15 2020  

Abstract: Computer vision plays a key role to measure the relative posture and position between the spacecrafts, especially in various important space tasks. As one of the essential steps for computer vision, camera calibration is important for obtaining precise three-dimensional contours of the space target. However, it is impossible to use the traditional calibration targets to calibrate the space camera in orbit. To solve this problem, in this paper, we attack the on-orbit space camera calibration problem by using two steps. First, we only use two images of the solar panel, which is a commonly used element of majority human-made spacecraft, to generate an approximate initial estimation of the camera intrinsic parameters. In order to improve the robustness and accuracy of our method, the second step optimizes the initial solution by using an improved genetic algorithm (IGA). Simulated and real experiments prove that the proposed method is accurate and flexible, and shows good robust performance. Therefore, our method has realistic significance for various space tasks.

Accession Number: WOS:000562377900015

ISSN: 0030-4018

eISSN: 1873-0310

Record 36 of 327

Title: TiO₂-based compact TM-pass polarizer at visible wavelengths with ultra-low power loss

Author(s): Zhao, QF (Zhao, Qinfeng); Yu, WQ (Yu, Wenqi); Zhao, YR (Zhao, Yiru); Dai, SX (Dai, Shuangxing); Liu, JG (Liu, Jianguo)

Source: OPTICS COMMUNICATIONS  Volume: 475  Article Number: 126282  DOI: 10.1016/j.optcom.2020.126282  Published: NOV 15 2020  

Abstract: A compact transverse magnetic (TM)-pass/transverse electric (TE)-stop polarizer with ultra-low power loss at visible wavelengths is theoretically proposed on a TiO2-based platform, which is achieved via the surface plasmon polaritons effect in the hybrid plasmonic grating structure. We design the TiO2 waveguide and optimize the structural parameters of the hybrid plasmonic grating using finite element method (FEM) and 3D Finite-Difference-Time-Domain (FDTD) simulation. The proposed polarizer shows a high extinction ratio over 27 dB from the wavelength of 0.54 to 0.57 pm, a low insertion loss of 0.087 dB at 0.552 pm, a compact size of only 2.64 pm and a great fabrication error tolerance.

Accession Number: WOS:000563999900008

Author Identifiers:

ISSN: 0030-4018

eISSN: 1873-0310

Record 37 of 327

Title: Optical trapping of single nano-size particles using a plasmonic nanocavity

Author(s): Zhang, JC (Zhang, Jiachen); Lu, FF (Lu, Fanfan); Zhang, WD (Zhang, Wending); Yu, WX (Yu, Weixing); Zhu, WR (Zhu, Weiren); Premaratne, M (Premaratne, Malin); Mei, T (Mei, Ting); Xiao, FJ (Xiao, Fajun); Zhao, JL (Zhao, Jianlin)

Source: JOURNAL OF PHYSICS-CONDENSED MATTER  Volume: 32  Issue: 47  Article Number: 475301  DOI: 10.1088/1361-648X/abaead  Published: NOV 11 2020  

Abstract: Trapping and manipulating micro-size particles using optical tweezers has contributed to many breakthroughs in biology, materials science, and colloidal physics. However, it remains challenging to extend this technique to a few nanometers particles owing to the diffraction limit and the considerable Brownian motion of trapped nanoparticles. In this work, a nanometric optical tweezer is proposed by using a plasmonic nanocavity composed of the closely spaced silver coated fiber tip and gold film. It is found that the radial vector mode can produce a nano-sized near field with the electric-field intensity enhancement factor over 10(3)through exciting the plasmon gap mode in the nanocavity. By employing the Maxwell stress tensor formalism, we theoretically demonstrate that this nano-sized near field results in a sharp quasi-harmonic potential well, capable of stably trapping 2 nm quantum dots beneath the tip apex with the laser power as low as 3.7 mW. Further analysis reveals that our nanotweezers can stably work in a wide range of particle-to-tip distances, gap sizes, and operation wavelengths. We envision that our proposed nanometric optical tweezers could be compatible with the tip-enhanced Raman spectroscopy to allow simultaneously manipulating and characterizing single nanoparticles as well as nanoparticle interactions with high sensitivity.

Accession Number: WOS:000566139500001

PubMed ID: 32870814

Author Identifiers:

ISSN: 0953-8984

eISSN: 1361-648X

Record 38 of 327

Title: Screen printing of upconversion NaYF₄:Yb<SUP>3+</SUP>/Eu<SUP>3+</SUP> with Li<SUP>+</SUP> doped for anti-counterfeiting application

Author(s): Li, DD (Li, Dongdong); Mo, JY (Mo, Jianye); Wang, C (Wang, Chong); Liu, W (Liu, Wei); Ge, HB (Ge, Haibo); Han, DD (Han, Dongdong); Hao, AH (Hao, Aihua); Chai, BY (Chai, Baoyu); She, JB (She, Jiangbo)

Source: CHINESE OPTICS LETTERS  Volume: 18  Issue: 11  Article Number: 110501  DOI: 10.3788/COL202018.110501  Published: NOV 10 2020  

Abstract: Li ions affect the upconversion efficiency by changing the local crystal field of the luminescent center. Herein, in order to improve the upconversion efficiency of NaYF4:Yb3+/Eu3+, a series of NaYF4:Yb3+/Eu3+ micro-particles with different Li+ doping concentrations were synthesized by the hydrothermal synthesis method, respectively. Firstly, the structure and morphology of NaYF4:Yb3+/Eu3+ upconversion micro-particles (UCMPs) with differ-ent doping concentrations were analyzed by X-ray diffraction and a scanning electron microscope (SEM). SEM results show that the UCMPs are not only highly crystallized, but also have hexagons with different Li+ concentrations of NaYF4:Yb3+/Eu3+. X-ray diffraction shows that the crystal field around Eu3+ changes with the increase of Li+ concentration. Then, the fluorescence spectrum of NaYF4:Yb3+/Eu3+ was studied under the irradiation of a 980 nm laser. The results show that the fluorescence intensity of NaYF4:Yb3+/Eu3+ with 2% Li+ is the strongest, which is twice the intensity of NaYF4:Yb3+/Eu3+ without Li+. Finally, the fluorescence imaging analysis of NaYF4:Yb3+/Eu3+ with 2% Li+ concentration was carried out. The UCMPs are used to screen printing to evaluate the imaging effect on different sample surfaces. The results show NaYF4:Yb3+/Eu3+ (with 2% Li+) has great application prospects in anti-counterfeiting recognition.

Accession Number: WOS:000591933400006

ISSN: 1671-7694

Record 39 of 327

Title: Spatial attention based visual semantic learning for action recognition in still images

Author(s): Zheng, YP (Zheng, Yunpeng); Zheng, XT (Zheng, Xiangtao); Lu, XQ (Lu, Xiaoqiang); Wu, SY (Wu, Siyuan)

Source: NEUROCOMPUTING  Volume: 413  Pages: 383-396  DOI: 10.1016/j.neucom.2020.07.016  Published: NOV 6 2020  

Abstract: Visual semantic parts play crucial roles in still image-based action recognition. A majority of existing methods require additional manual annotations such as human bounding boxes and predefined body parts besides action labels to learn action related visual semantic parts. However, labeling these manual annotations is rather time-consuming and labor-intensive. Moreover, not all manual annotations are effective when recognizing a specific action. Some of them can be irrelevant and even misguided. To address these limitations, this paper proposes a multi-stage deep learning method called Spatial Attention based Action Mask Networks (SAAM-Nets). The proposed method does not need any additional annotations besides action labels to obtain action-specific visual semantic parts. Instead, we propose a spatial attention layer injected in a convolutional neural network to create a specific action mask for each image with only action labels. Moreover, based on the action mask, we propose a region selection strategy to generate a semantic bounding box containing action-specific semantic parts. Furthermore, to effectively combine the information of the whole scene and the sematic box, two feature attention layers are adopted to obtain more discriminative representations. Experiments on four benchmark datasets have demonstrated that the proposed method can achieve promising performance compared with state-of-the-art methods. (C) 2020 Elsevier B.V. All rights reserved.

Accession Number: WOS:000579803700032

Author Identifiers:

ISSN: 0925-2312

eISSN: 1872-8286

Record 40 of 327

Title: Hyperspectral deep convolution anomaly detection based on weight adjustment strategy

Author(s): Chong, D (Chong, Dan); Hu, BL (Hu, Bingliang); Gao, XH (Gao, Xiaohui); Gao, H (Gao, Hao); Xia, P (Xia, Pu); Wu, YH (Wu, Yinhua)

Source: APPLIED OPTICS  Volume: 59  Issue: 31  Pages: 9633-9642  DOI: 10.1364/AO.400563  Published: NOV 1 2020  

Abstract: Hyperspectral anomaly detection has garnered much research in recent years due to the excellent detection ability of hyperspectral remote sensing in agriculture, forestry, geological surveys, environmental monitoring, and battlefield target detection. The traditional anomaly detection method ignores the non-linearity and complexity of the hyperspectral image (HSI), while making use of the effectiveness of spatial information rarely. Besides, the anomalous pixels and the background are mixed, which causes a higher false alarm rate in the detection result. In this paper, a hyperspectral deep net-based anomaly detector using weight adjustment strategy (WAHyperDNet) is proposed to circumvent the above issues. We leverage three-dimensional convolution instead of the two-dimensional convolution to get a better way of handling high-dimensional data. In this study, the determinative spectrum-spatial features are extracted across the correlation between HSI pixels. Moreover, feature weights in the method are automatically generated based on absolute distance and the spectral similarity angle to describe the differences between the background pixels and the pixels to be tested. Experimental results on five public datasets show that the proposed approach outperforms the state-of-the-art baselines in both effectiveness and efficiency. (C) 2020 Optical Society of America

Accession Number: WOS:000583718000001

PubMed ID: 33175802

Author Identifiers:

ISSN: 1559-128X

eISSN: 2155-3165

Record 41 of 327

Title: Reconstruction of compressed video via non-convex minimization

Author(s): Ji, C (Ji, Chao); Tian, JS (Tian, Jinshou); Sheng, L (Sheng, Liang); He, K (He, Kai); Xin, LW (Xin, Liwei); Yan, X (Yan, Xin); Xue, YH (Xue, Yanhua); Zhang, MR (Zhang, Minrui); Chen, P (Chen, Ping); Wang, X (Wang, Xing)

Source: AIP ADVANCES  Volume: 10  Issue: 11  Article Number: 115207  DOI: 10.1063/5.0022860  Published: NOV 1 2020  

Abstract: This paper studies the sparsity prior to compressed video reconstruction algorithms. An effective non-convex 3DT(P)V regularization (0 < p < 1) is proposed for sparsity promotion. Based on the augmented Lagrangian reconstruction algorithm, this paper analyzes and compares three non-convex proximity operators for the lp-norm function, and numerous simulation results confirmed that the 3DT(P)V regularization can gain higher video reconstruction quality than the existing convex regularization and is more competitive than the existing video reconstruction algorithms.

Accession Number: WOS:000590780300002

Author Identifiers:

eISSN: 2158-3226

Record 42 of 327

Title: Time-resolved characteristics of laser induced breakdown spectroscopy on non-flat samples by single beam splitting

Author(s): Lei, BY (Lei, Bingying); Xu, BP (Xu, Boping); Wang, J (Wang, Jing); Li, J (Li, Jing); Wang, YS (Wang, Yishan); Tang, J (Tang, Jie); Zhao, W (Zhao, Wei); Duan, YX (Duan, Yixiang)

Source: RSC ADVANCES  Volume: 10  Issue: 65  Pages: 39553-39561  DOI: 10.1039/d0ra06582j  Published: NOV 1 2020  

Abstract: A single-beam-splitting approach was used to enhance the signal intensity of LIBS under the extreme conditions of laser beam grazing of the surface of non-flat samples. Time-resolved spectra show that the laser-ablated plasma presents a stronger spectral intensity and a slower plasma decay in the split beam mode because of the higher laser irradiance. The temporal evolutions of signal enhancement factors indicate that the enhancement effect first rises and then drops with delay time and the maximum enhancement factor of Al plasma comes later than that of Cu plasma under the same laser energy. The mechanisms behind it are discussed. It is also found that the electron density exhibits a faster decay with delay time in the split beam mode, mainly due to the faster plasma expansion. And a slower increase of electron density with laser energy is observed in the split beam mode because of the plasma shielding effect.

Accession Number: WOS:000584324000020

PubMed ID: 35515415

Author Identifiers:

eISSN: 2046-2069

Record 43 of 327

Title: Research on Microhole Processing Technology Based on the Femtosecond-Laser Spiral Trepanning Method

Author(s): Li, FP (Li, Fengping); Feng, G (Feng, Guang); Yang, XJ (Yang, Xiaojun); Li, XG (Li, Xiaogang); Ma, G (Ma, Guang); Lu, CJ (Lu, Chengji)

Source: APPLIED SCIENCES-BASEL  Volume: 10  Issue: 21  Article Number: 7508  DOI: 10.3390/app10217508  Published: NOV 2020  

Abstract: Featured Application
Film hole; fuel injection nozzle; microfluidic chips.
Microholes have crucial applications in aerospace, the automotive industry, and other industries. In this study, the microhole processing technology based on the femtosecond-laser spiral trepanning method was investigated. By adjusting the spiral scanning path, laser power distribution, and defocusing amount to control laser energy distribution, an inverted cone hole, straight hole, and normal cone hole were obtained finally. The morphology and element of the microhole were investigated by scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX). The experimental results of the femtosecond-laser spiral trepanning method could achieve fewer impurities. Finally, the formation mechanisms of different microholes are explained in detail. The method is simpler and more efficient than the traditional microhole processing technology. The femtosecond-laser spiral trepanning method with controllable hole roundness, accuracy, and taper has important practical significance in microhole processing.

Accession Number: WOS:000589028100001

Author Identifiers:

eISSN: 2076-3417

Record 44 of 327

Title: Atmospheric correction of geostationary satellite ocean color data under high solar zenith angles in open oceans

Author(s): Li, H (Li, Hao); He, XQ (He, Xiangqiang); Bai, Y (Bai, Yan); Shanmugam, P (Shanmugam, Palanisamy); Park, YJ (Park, Young-Je); Liu, J (Liu, Jia); Zhu, QK (Zhu, Qiankun); Gong, F (Gong, Fang); Wang, DF (Wang, Difeng); Huang, HQ (Huang, Haiqing)

Source: REMOTE SENSING OF ENVIRONMENT  Volume: 249  Article Number: 112022  DOI: 10.1016/j.rse.2020.112022  Published: NOV 2020  

Abstract: With a revisit time of 1 h, spatial resolution of 500 m, and high radiometric sensitivity, the Geostationary Ocean Color Imager (GOCI) is widely used to monitor diurnal dynamics of oceanic phenomena. However, atmospheric correction (AC) of GOCI data with high solar zenith angle ( > 70 degrees) is still a challenge for traditional algorithms. Here, we propose a novel neural network (NN) AC algorithm for GOCI data under high solar zenith angles. Unlike traditional NN AC algorithms trained by radiative transfer-simulated dataset, our new AC algorithm was trained by a large number of matchups between GOCI-observed Rayleigh-corrected radiance in the morning and evening and GOCI-retrieved high-quality noontime remote-sensing reflectance (Rrs). When validated using hourly GOCI data, the new NN AC algorithm yielded diurnally stable Rrs in open ocean waters from the morning to evening. Furthermore, when validated by in-situ data from three Aerosol Robotic Network-Ocean Color (AERONET-OC) stations (Socheongcho, Gageocho and Ieodo), the GOCI-retrieved Rrs at visible bands obtained using the new AC algorithm agreed well with the in-situ values, even under high solar zenith angles. Practical application of the new algorithm was further examined using diurnal GOCI observation data acquired in clear open ocean waters. Results showed that the new algorithm successfully retrieved Rrs for the morning and evening GOCI data. Moreover, the amount of Rrs data retrieved by the new algorithm was much higher than that retrieved by the standard AC algorithm in SeaDAS. Our proposed NN AC algorithm can not only be applied to process GOCI data acquired in the morning and evening, but also has the potential to be applied to process polar-orbiting satellite ocean color data at high-latitude ocean that also include satellite observation with high solar zenith angles.

Accession Number: WOS:000571214600004

Author Identifiers:

ISSN: 0034-4257

eISSN: 1879-0704

Record 45 of 327

Title: Generation of multimode quantum correlation with energy-level cascaded four-wave mixing processes

Author(s): Li, JW (Li, Jiawei); Li, W (Li, Wei); Niu, MQ (Niu, Mengqi); Lin, YX (Lin, Yixing); Li, CB (Li, Changbiao); Cai, Y (Cai, Yin); Zhang, YP (Zhang, Yanpeng)

Source: ANNALS OF PHYSICS  Volume: 422  Article Number: 168316  DOI: 10.1016/j.aop.2020.168316  Published: NOV 2020  

Abstract: Multimode quantum correlation has important applications in the field of quantum information. In this paper, we propose a compact scheme to generate multiple quantum correlated beams based on energy-level cascaded four-wave mixing (EC-FWM) process in a single atomic medium of rubidium. Injecting two strong pump beams with different frequencies and one weak probe beam into one rubidium vapor, four possible paramet-rically amplified FWM (PA FWM) processes can coexist under different phase matching conditions. Within the scheme, the weak probe beam is amplified and three coherent beams are generated, which can also be seen as an eight-wave mixing (EWM) process when certain phase matching condition is satisfied. Based on the energy level system of the scheme, three different cascaded structure models are employed to study the quantum correlation between the four generated beams. Amplitude and phase quadratures squeezing and intensity squeezing of the threeand four-mode are calculated via the input-output relations of the system. We found versatile multimode squeezing can be generated in all the structures, but the degree of squeezing and its distribution among the modes are different, depending on the specific structure. Furthermore, the relation of the quantum correlation, as well as the eigenmodes and eigenvalues of the four-mode quantum states are studied. (C) 2020 Elsevier Inc. All rights reserved.

Accession Number: WOS:000591352500008

Author Identifiers:

ISSN: 0003-4916

eISSN: 1096-035X

Record 46 of 327

Title: A plagioclase-rich rock measured by Yutu-2 Rover in Von Karman crater on the far side of the Moon

Author(s): Ma, P (Ma, Pei); Sun, YX (Sun, Yuxue); Zhu, MH (Zhu, Meng-Hua); Yang, YZ (Yang, Yazhou); Hu, XY (Hu, Xiaoyi); Jiang, T (Jiang, Te); Zhang, H (Zhang, Hao); Lucey, PG (Lucey, Paul G.); Xu, R (Xu, Rui); Li, CL (Li, Chunlai); He, ZP (He, Zhiping); Xue, B (Xue, Bin); Yang, JF (Yang, Jianfeng); Huang, CN (Huang, Changning); Lin, HY (Lin, Hongyu)

Source: ICARUS  Volume: 350  Article Number: 113901  DOI: 10.1016/j.icarus.2020.113901  Published: NOV 1 2020  

Abstract: The Chang'E-4 spacecraft successfully landed in Von K.arm.an crater inside the South Pole-Aitken basin on the lunar far side on January 3, 2019 and the Yutu-2 Rover has performed explorations on the lunar surface for nine lunar days as of September 2019. Our earlier analysis of the visible and near-infrared spectrometer measurements made by the Yutu-2 rover during the first two lunar days shows that the regolith of the landing site may have come from the nearby Finsen crater and is dominated by plagioclase with lesser amount of mafic minerals. During its third lunar day explorations, the Yutu-2 photographed a small piece of lunar rock and measured its reflectance spectra. Compared with the spectra of its surrounding regolith, this rock's spectrum has deeper absorption features, indicating its fresher nature. To obtain the mineralogy of the rock, we compared the rock's spectrum with the spectral library data of NASA's reflectance experiment laboratory of returned lunar rocks and lunar meteorites. We found that this rock is also plagioclase-rich with a possible plagioclase abundance of 60-80 vol%. A source region analysis using the Moon Mineralogy Mapper's remote sensing observations indicates this rock was ejected from the Zhinyu crater, about 30 km west of the landing site, rather than directly from the Finsen crater. Numerical simulations of the Zhinyu crater on the impact cratering process and ejecta thickness distribution confirmed our findings and imply that the surficial materials at the CE-4 landing site experienced a complicated evolution rather than simply retaining the pristine or primordial ejecta directly from the Finsen crater.

Accession Number: WOS:000554912400014

Author Identifiers: