2020
2020
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Record 325 of
Title:Preparation and properties of Co0.85Se/RGO composite counter electrodes for quantum-dot-sensitized solar cells
Author(s):Zhang, Maolin(1); Li, Jing(1); Nie, Zhiqiang(2); Zhang, Dongyan(1); Yan, Yangxi(1); Li, Zhimin(1)Source: Journal of Optoelectronics and Advanced Materials Volume: 22 Issue: 1-2 DOI: null Published: January 2020Abstract:Counter electrodes (CEs) are fundamentally important components of quantum-dot-sensitized solar cells (QDSSCs), helping to transfer electrons from external circuit to electrolyte and acting as catalysts. In this work, Co0.85Se/RGO composite films were synthesized via one-step solvothermal process. X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive spectrometer (EDS) were utilized to characterize the structure, morphology and elemental distribution of the composite CEs. The photovoltaic studies revealed that the composite CEs could yield PCE reaching 2.6% when assembled with CdS/CdSe/TiO2 photoanodes for QDSSCs. EIS and Tafel polarization indicated that the enhanced performances were due to combined high catalytic properties of Co0.85Se with better electron conductivity of RGO. ? 2020 National Institute of Optoelectronics. All rights reserved.Accession Number: 20203409077155 -
Record 326 of
Title:Research on influencing factors of natural frequency of shafting
Author(s):Xiaodong, Chen(1,2); Youjin, Xie(1); Zhiguo, Li(1,2); Wei, Hao(1,2); Xiong, Gao(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11570 Issue: DOI: 10.1117/12.2579508 Published: 2020Abstract:Solar Array Drive Assembly(SADA) is a core component of high-power and long-life satellites, and the shafting is an important part of SADA. Its vibration characteristics analysis is very important in structural design and dynamic analysis. The paper theoretically derived and calculated the natural frequency of the shaft system under the action of bearing preload and span, and established a corresponding finite element simulation model in ANSYS. It is concluded that the natural frequency of the shafting increases with the increase of the bearing preload and the span, and the influence of the bearing span is more significant. ? 2020 SPIE. All rights reserved.Accession Number: 20204909580472 -
Record 327 of
Title:Exoplanet detection methods and transit spectrometer equipment of astronomical telescopes
Author(s):Wang, Fang(1,2); Fan, Xuewu(1,2); Wang, Hu(1,2); Shen, Yang(1); Pan, Yue(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11567 Issue: DOI: 10.1117/12.2579795 Published: 2020Abstract:With the continuous development of astronomy theory and space exploration technology, searching for extrasolar planets has become one of the most active research topics in astronomy. In recent decades, countries around the world have invested a lot of ground and space projects in this search field and obtained abundant results. Firstly, this paper summarizes the mainstream exoplanet detection methods such as radial velocity, transit and direct imaging method with the outline of the principles and features. Then, several instruments for obtaining the spectrum of exoplanets are introduced, focusing on the optical system parameters of telescopes and spectrometers. Finally, according to the comprehensive discussion above, the future development trend of exploration missions and instrument design in this field is predicted, and it is recognized that these survey missions for detecting and characterizing exoplanets are of great significance for searching biological signals outside the solar system. ? 2020 SPIE.Accession Number: 20205009602506 -
Record 328 of
Title:Study on the photometric characteristics of CCR for space autonomous RVD
Author(s):Wang, Hu(1,2); Liu, Jie(1); Xue, Yaoke(1); Liu, Meiying(1,2); Liu, Yang(1,2); Lin, Shangmin(1,2); Wang, Fang(1,2); Shen, Yang(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11567 Issue: DOI: 10.1117/12.2579799 Published: 2020Abstract:In this paper, the photometric characteristics of passively marked corner-cube-reflector-class cooperative targets are studied. The imaging characteristics of corner cube reflector(CCR) are discussed theoretically, and the influencing factors such as surface accuracy, angle error and diffraction effect are analyzed. The reflection uniformity and diffraction characteristics of CCRs with different positions and different precision are simulated and verified. In addition, the influencing factors and control methods of CCR precision are proposed. To the photometric characteristics of cooperative targets, especially the influence of aperture size of cube-corner prism on comprehensive aberration, the transmission surface (bottom surface) on comprehensive aberration was concerned firstly, besides the three reflection surfaces. The conclusion was been drawn that the transmission surface and the three reflection surfaces had most effect on the parallel of emerging beams, and the minimum error was the minimum algebra sum of above four surfaces. It can provide theoretical support for on-orbit services such as companion flight, autonomous rendezvous and docking (RVD). ? 2020 SPIE.Accession Number: 20205009602507 -
Record 329 of
Title:Comparison of short focal length dual-fields LWIR optical lens
Author(s):Mei, Chao(1); Liang, Chenguang(2); Ma, Yingjun(1); Fei, Jiaqi(1); Guo, Huinan(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11567 Issue: DOI: 10.1117/12.2575902 Published: 2020Abstract:With the development of infrared surveillance technology, the short focus zoom LWIR lens has been paid to more and more attention. In this paper, dual fields zoom lens with the fields of 20*25/8*10 are designed by two different methods. The main specifications of the lens include: aperture is 1 / 2, detector resolution is 640 * 512, pixel size is 15 m, temperature adaptability is -40 to + 60 . And we compare the volume, weight, imaging transmission, transmissivity and economy of the lens by different methods. It is found that the re-imaging method has smaller volume, weight and economy. While another imaging method has better transmittance, so the imaging system can reach higher noise equivalent power at the same image quality ? 2020 SPIE.Accession Number: 20205009602557 -
Record 330 of
Title:Ultrafast Soliton Dynamics of Micro-Combs Observed by Aberration-Free Temporal Magnifier
Author(s):Chen, Liao(1); Zhao, Yanjing(1); Wang, Weiqiang(2,3); Hu, Hao(1); Wang, Ruolan(1); Wang, Xinyu(2,3); Chu, Sai T.(4); Little, Brent(2); Zhang, Chi(2,3); Zhang, Wenfu(1); Zhang, Xinliang(1)Source: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS Volume: 2020-May Issue: DOI: null Published: May 2020Abstract:Ultra-fast soliton dynamics of micro-combs are investigated based on an aberration-free temporal magnifier. By eliminating aberrations, temporal window is greatly extended to 1.4 ns and transient phenomena are clearly observed including soliton annihilation and mergence. ? 2020 OSA.Accession Number: 20204009261629 -
Record 331 of
Title:The athermalization design of an airborne all-day star sensor optical system
Author(s):Zhou, Canglong(1,2); Wang, Hu(1,2); Xue, Yaoke(1); Shen, Yang(1); Pan, Yue(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11570 Issue: DOI: 10.1117/12.2580288 Published: 2020Abstract:With the continuous development of navigation technology, celestial navigation system has gradually become the essential of celestial navigation system with its advantages of autonomy is strong, good concealment and high precision. The key component of the astronomical navigation system is the all-day star sensor. With the improvement of navigation accuracy, higher requirements have been put forward for the design of all-day star sensor, which is required to be able to work normally within 24 hours. The temperature range of the star sensor working on the airborne platform is very wide, and the temperature has a great impact on the imaging performance of the star sensor, thus affecting the positioning accuracy of navigation. Therefore, it is of great practical significance to ensure that its optical performance does not change within such a wide range of temperature, so as to significantly improve its navigation and positioning accuracy. ? 2020 SPIE. All rights reserved.Accession Number: 20204909580488 -
Record 332 of
Title:Infrared patch-tensor model with a new tensor nuclear norm for small target detection in the ground background
Author(s):Li, Ruimei(1,2); Yao, Dalei(1); Qiu, Yuehong(1); Bu, Fan(1); Wang, Li(1)Source: Proceedings of 2020 IEEE International Conference on Information Technology, Big Data and Artificial Intelligence, ICIBA 2020 Volume: Issue: DOI: 10.1109/ICIBA50161.2020.9277418 Published: November 6, 2020Abstract:Accurate detection of infrared small target in complex scenes plays a vital role in many practical applications. In the infrared patch-tensor (IPT) model, small target detection is regarded as a convex optimization problem of tensor robust principal component analysis (TRPCA), which separates low tubal rank and sparse tensors. Tensor singular value thresholding is employd as the proximal operation of tensor nuclear norm to estimate the low-rank background components. Considering the defect that the local structural weights in the Reweighted IPT shrink excessively small targets, an effective local prior map is used to better mine target and background information. The local prior and sparse enhancement weight are combined to obtain the final adaptive weight. Alternating direction method of multipliers (ADMM) is utilized to solve the model. Extensive experiments of infrared sequence images based on ground background prove that our algorithm has significant advantages in real-time and detection capability compared with state-of-the-arts. ? 2020 IEEE.Accession Number: 20210309780144 -
Record 333 of
Title:Research on image preprocessing techniques needed for long-distance camera scanning Fourier ptychographic imaging
Author(s):Wang, Jing(1); Zhao, Hui(2); Yang, Mingyang(1); Li, Zhixin(1); Xiang, Meng(1); Wang, Yuming(1); Fan, Xuewu(2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11567 Issue: DOI: 10.1117/12.2579989 Published: 2020Abstract:With the development of the fourier ptychography in microscopy imaging, more and more researchers consider applying fourier ptychography in long-distance imaging. However being different from microscopic imaging, long distance fourier ptychographic imaging will face more challenges, one of which is the source image quality. In this manuscript, the influence of the source image quality on camera scanning FP imaging will be investigated and simulated. In the first part, the calibration aims to solve the influence of unenenly illumination. After that, a poisson-gaussian mixed noise model based denoising is uesd and could effectively suppresses the noise through parameter estimation. Finally, Phase correalation regisitrtion has to be used to correct the mismatch between adjacent images caused by camera scanning mode. The simulation results demonstrate the effectiveness of the preprocessing methods and could make FP more robust.The signal to noise ratio could reach to 40.5dB while obtained 5*improvement in resolution. ? 2020 SPIE.Accession Number: 20205009602525 -
Record 334 of
Title:Research on flexible structure of a space flight prototype Doppler asymmetric spatial heterodyne interferometer
Author(s):Dang, Jianan(1,2); Sun, Jian(1); Feng, Yutao(1); Chang, Chenguang(1); Wu, Yang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11564 Issue: DOI: 10.1117/12.2580203 Published: 2020Abstract:As a new type of wind field detection technology, Doppler Asymmetric Spatial Heterodyne?1/4DASH?1/4‰can invert information such as atmospheric wind speed by monitoring the Doppler frequency shift of the absorption line or emission line of the atmospheric composition. It is widely used in the detection of middle and upper atmospheric wind fields. In this paper, a flexible support structure suitable for DASH interferometer is designed, so that the bonding process between different materials has a high safety margin in environmental testing. After modal analysis and random vibration analysis of the whole structure, the results show that the design meets the requirements. First, the fundamental frequency of the interferometer (765.79Hz>100Hz) meets the requirements of general satellites for the load; secondly, the random vibration analysis results show that the bonding stress between the surfaces is less than the allowable stress of the material (2MPa2); finally, the optical parts and structural parts did not collide with the structural parts during the vibration process, and the flexible structure did not undergo plastic deformation, and the whole structure of the interferometer was safe and reliable ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Accession Number: 20204909588271 -
Record 335 of
Title:Blood pressure evaluation based on photoplethysmography using deep learning
Author(s):Xiaoxiao, Sun(1,2); Liang, Zhou(2); Zhaohui, Liu(2); Jiangjun, Yu(1,2); Wenlong, Qiao(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11566 Issue: DOI: 10.1117/12.2576841 Published: 2020Abstract:In recent years, the number of patients with hypertension has increased. Hypertension is an invisible killer. Long-term hypertension can cause a series of cardiovascular diseases such as angina pectoris, stroke, and heart failure. Therefore, early evaluation and grade assessment of blood pressure (BP) are essential to human health. The seventh report of the National Joint Committee for the Prevention, Detection, Evaluation, and Treatment of Hypertension in the United States (JNC7) classified BP levels into normotension (NT), prehypertension (PHT) and hypertension (HT). In this paper, we adopted a deep learning model (ResNet18) based on the ensemble empirical mode decomposition (EEMD) and the Hilbert Transform (HT) to predict the risk level of BP only using photoplethysmography (PPG) signals. We collected 582 data records from the Multiparameter Intelligent Monitoring in Intensive Care database (MIMIC), and each file contained arterial BP signals as the labels for inputs and the corresponding PPG signals as the inputs. Besides, the last fully connected layer of the model was initialized. We conducted three classification experiments: HT vs. NT, HT vs. PHT, and (HT + PHT) vs. NT, the F1 score of these three classification experiments is 88.03%, 70.94%, and 84.88%, respectively. A quick and accessible noninvasive BP evaluation method was offered to low- and middle-income countries. ? 2020 SPIE. All rights reserved.Accession Number: 20204909589265 -
Record 336 of
Title:Ultrafast soliton dynamics of micro-combs observed by aberration-free temporal magnifier
Author(s):Chen, Liao(1); Zhao, Yanjing(1); Wang, Weiqiang(2,3); Hu, Hao(1); Wang, Ruolan(1); Wang, Xinyu(2,3); Chu, Sai T.(4); Little, Brent(2); Zhang, Chi(1); Zhang, Wenfu(2,3); Zhang, Xinliang(1)Source: Optics InfoBase Conference Papers Volume: Part F181-CLEO-AT 2020 Issue: DOI: 10.1364/CLEO_AT.2020.JW2F.30 Published: 2020Abstract:Ultra-fast soliton dynamics of micro-combs are investigated based on an aberration-free temporal magnifier. By eliminating aberrations, temporal window is greatly extended to 1.4 ns and transient phenomena are clearly observed including soliton annihilation and mergence. ? OSA 2020 ? 2020 The Author(s).Accession Number: 20204509460101