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arXiv 2021年

作者： Kuang, Zhian Sun, Liting Gao, Huijun Tomizuka, Masayoshi Research Institute of Intelligent Control and Systems Harbin Institute of Technology Harbin150001 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Mechanical Control System Lab Mechanical Engineering Department University of California BerkeleyCA94720 United States

In this paper, a practical fractional-order variable-gain super-twisting algorithm (PFVSTA) is proposed to improve the tracking performance of wafer stages for semiconductor manufacturing. Based on the sliding mode control (SMC), the proposed PFVSTA enhances the tracking performance from three aspects: 1) alleviating the chattering phenomenon via super-twisting algorithm and a novel fractional-order sliding surface (FSS) design, 2) improving the dynamics of states on the sliding surface with fast response and small overshoots via the designed novel FSS and 3) compensating for disturbances via variable-gain control law. Based on practical conditions, this paper analyzes the stability of the controller and illustrates the theoretical principle to compensate for the uncertainties caused by accelerations. Moreover, numerical simulations prove the effectiveness of the proposed sliding surface and control scheme, and they are in agreement with the theoretical analysis. Finally, practice-based comparative experiments are conducted. The results show that the proposed PFVSTA can achieve much better tracking performance than the conventional methods from various perspectives. Copyright © 2021, The Authors. All rights reserved.

关键词： Sliding mode control

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SAR Image Classification Algorithm Based on Improved SIFT Features

SAR Image Classification Algorithm Based on Improved SIFT Fe...

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Progress in Electromagnetic Research Symposium (PIERS)

作者： Yuting Cui Tao Tang Xiaoyan Zhou Kefeng Ji State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System National University of Defense Technology China

ISBN: (纸本)9781665409889

With the advancement and development of Synthetic Aperture Radar (SAR) technology, target classification and interpretation based on SAR image data has become one of a hot research directions for domestic and foreign scholars. Most early SAR image interpretation work relies on overall features or original intensity values, such as template-based classification methods, but such methods are very sensitive to local changes. So, it is necessary to find a method that can effectively extract the local features of the image. In order to improve the recognition performance of vehicle targets in SAR images, this paper summarizes a method suitable for vehicle target recognition in SAR images by testing key points and local descriptors. First, In the key-point detection module, Difference of Gaussian, Harris corner detection, and Features From Accelerated Segment Test (FAST) algorithms are used to generate key-point. In the descriptor extraction module, different modes are used for descriptor gradient statistics to extract Scale Invariant Feature Transform (SIFT) descriptors; secondly, the SIFT feature points are clustered using K-Nearest Neighbor (KNN) to generate a dictionary (Bag of words), then use the Spatial Pyramid matching (SPM) algorithm to generate the feature vector of the picture and use the Support Vector Machines (SVM) classifier for classification; finally, the detection performance of these algorithms is quantitatively analyzed and the optimal performance module is selected to combine modules as the final classification algorithm. It was verified on the Moving and Stationary Target Acquisition and Recognition (MSTAR) data set, and the results showed that the performance of the algorithm has been greatly improved than before.

关键词： Support vector machines Dictionaries Target recognition Clustering algorithms Transforms Feature extraction Radar polarimetry

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Self-Frequency-Doubled Crystal Laser Light Sources and its Potential Applications in Automotive Lighting 18

Self-Frequency-Doubled Crystal Laser Light Sources and its P...

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18th China International Forum on Solid state Lighting and 7th International Forum on Wide Bandgap Semiconductors, SSLChina: IFWS 2021

作者： Li, Ru Zheng, Xianliang Yu, Haohai Long, Zhen Hu, Zhanggui Li, Zhaohui Chang, Jin Huang, Limin Yin, Liwei Changzhou Xingyu Automotive Lighting System Co. Ltd. Changzhou City Jiangsu China Shandong University State Key Laboratory of Crystal Materials Shandong Changzhou China Tianjin University of Technology Institute of Functional Crystals Tianjin Changzhou China

ISBN: (纸本)9781665495462

With the rapid development of informatization and intelligentialize of vehicles, solid-state-lighting is becoming more and more important in automotive lighting. LED still have some problems in lighting, such as low light intensity, thermal attenuation and short projecting distance. Laser lighting is becoming one of substitutes as the light source for automotive lighting. Here, laser light sources based on self-frequency-doubled (SFD) crystal were investigated. Especially for white laser light source, a mockup was made to verify the realistic of this approach, and the test results showed that the SFD white laser light source, combined with a blue laser diode and an SFD amber laser light source, was obtained successfully. The tested white laser light source's proportion of blue and amber is 1 (440nm): 1.7 (570nm), with a total output optical power 4W. In addition, a road projection lamp based on SFD green laser, compared with LED light source at same output optical power level, mock-up sample's were made and tested to further verify the feasibility of SFD laser applied on automotive lighting, and the optical simulation and test results were also demonstrated. Results show that SFD laser light source will play an important role in the future lighting market for automotive. © 2021 IEEE.

关键词： Amber

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A method for recognition of dynamic hand gestures based on wrist tendon sounds 22

A method for recognition of dynamic hand gestures based on w...

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22nd IEEE International Conference on E-Health Networking, Application and Services, HEALTHCOM 2020

作者： He, Bailin Wang, Can Wang, Hao Li, Mengyao Duan, Shengcai Wu, Xinyu Guangdong Provincial Key Laboratory of Robotics and Intelligent System Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China University of Chinese Academy of Sciences Beijing100049 China Department of Mechanical and Automation Engineering The Chinese University of Hong Kong Hong Kong Samsung Electronics Guangdong-Hong Kong-Macao Joint Laboratory of Human-Machine Intelligence-Synergy Systems Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China

ISBN: (纸本)9781728162676

Hand gesture recognition are widely applied in game industry and rehabilitation engineering. Some recognition methods based on physiological data are attracting attention. In this paper, a novel method for dynamic hand gesture recognition based on sounds of wrist tendon is proposed. Bone conduction sensors which automatically filter the ambient noise is utilized to collect the wrist tendon sounds of three types of dynamic hand gestures. Continuous Wavelet Transform(CWT) is utilized extract the features of sounds and Support Vector Machine(SVM) is utilized to train the classifier model. Five healthy subjects participated the experiment and the average test accuracy of three classes achieves 92.33%. The proposed method provides an effective perspective for hand gesture recognition. © 2021 IEEE.

关键词： Support vector machines

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Refractory black carbon aerosols in rainwater in the summer of 2019 in Beijing:Mass concentration,size distribution and wet scavenging ratio

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Journal of Environmental Sciences 2023年第10期132卷 31-42页

作者： Shandong Lei Baozhu Ge Hang Liu Jiannong Quan Danhui Xu Yuting Zhang Weijie Yao Lu Lei Yu Tian Qi Liao Xiaoyong Liu Jie Li Jinyuan Xin Yele Sun Pingqing Fu Junji Cao Zifa Wang Xiaole Pan State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089China National Center for Climate Change Strategy and International Cooperation Ministry of Ecology and EnvironmentBeijing 100035China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China Institute of Surface-Earth System Science Tianjin UniversityTianjin 300072China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100190China

Black carbon(BC)aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar *** lifetime of BC depends on atmospheric transport,aging and consequently on wet scavenging processes(in-cloud and below-cloud scavenging).In this study,sequential rainwater samples in eight rainfall events collected in 2 mm interval were measured by a tandem system including a single particle soot photometer(SP2)and a *** results showed that the volume-weighted average(VWA)mass concentrations of refractory black carbon(rBC)in each rainfall event varied,ranging from 10.8 to 78.9μg/*** highest rBC concentrations in the rainwater samples typically occurred in the first fraction from individual rainfall *** geometric mean median mass-equivalent diameter(MMD)decreased under precipitation,indicating that rBC with larger sizes was relatively aged and preferentially removed by wet scavenging.A positive correlation(R2=0.73)between the VWA mass concentrations of rBC in rainwater and that in ambient air suggested the important contribution of scavenging ***,the contributions of in-cloud and below-cloud scavenging were distinguished and accounted for 74%and 26%to wet scavenging,*** scavenging ratio of rBC particles was estimated to be 0.06 on *** study provides helpful information for better understanding the mechanism of rBC wet scavenging and reducing the uncertainty of numerical simulations of the climate effects of rBC.

关键词： Refractory black carbon Wet deposition Size distribution

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Controllable Energy Absorption Design and 3D Printing of High Energy Absorbing Biomimetic Double-Layer Impact-Resistant Structure

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Additive Manufacturing Frontiers 2025年第1期4卷

作者： Wang, Leilei Tong, Zhiqiang Song, Facheng Yin, Wencheng Wang, Ling Miao, Kai Li, Dichen State Key Laboratory for Manufacturing System Engineering School of Mechanical Engineering Xi'an Jiaotong University Xi'an 710054 China State Industry-Education Integration Center for Medical Innovations Xi'an Jiaotong University Xi'an 710049 China Engineering Technology Research Center for Rapid Manufacturing of Shaanxi Province Xi'an Jiaotong University Xi'an 710049 China

In engineering, the demand for high energy absorption by structures subjected to impact loads is increasing. Balancing the limited space, manufacturing feasibility, and energy absorption capabilities is a key point in the design of many enclosed structures with energy absorption requirements. To achieve a lightweight design and controllable energy absorption by the structures, within a limited space, this study proposes a bio-inspired double-layer impact-resistant structure that can be manufactured by an additive manufacturing method (powder bed fusion), inspired by the microstructure of a woodpecker's head. The structure is composed of two basic structural units: a quasi-circular ring and an oblique cylinder. The controllable energy absorption capabilities of the structure were studied through a combination of theoretical analyses, numerical simulations, and physical experiments. The results showed that, for the quasi-circular ring structure, the specific energy absorption range of 13–72 J/g could be effectively regulated by adjusting the structural parameters. The specific energy absorption range of 11–137 J/g could be effectively regulated for oblique cylindrical structures. Finally, the structure was applied to the design of engineering impact-resistant devices, proving the effectiveness of the controllable energy absorption of the structure. Moreover, the design process of the structure was optimized, laying a foundation for the structure to better serve engineering design applications. © 2025 The Author(s)

关键词： Additive manufacturing Bionic design Energy absorption Finite element analysis

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Dual topology and versatile Rashba-split surface state configurations in 2M−WS2 and 2M−WSe2

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Physical Review B 2025年第11期111卷 115151-115151页

作者： Lixuan Xu Yuqiang Fang Fuqiang Huang Shihao Zhang Shiheng Liang Yulin Chen Lexian Yang Zhongkai Liu Nan Xu Department of Physics Hubei University Wuhan 430062 China Key Laboratory of Intelligent Sensing System and Security (Hubei University) Ministry of Education Wuhan 430062 China School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China School of Physics and Electronics Hunan University Changsha 410082 China School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China ShanghaiTech Laboratory for Topological Physics Shanghai 201210 China Department of Physics University of Oxford Oxford OX1 3PU United Kingdom State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing 100084 China Institute for Advanced Studies (IAS) Wuhan University Wuhan 430072 China Wuhan Institute of Quantum Technology Wuhan 430206 China

The 2M-phase transition metal dichalcogenides have recently attracted intensive research interest due to their rich topological and superconducting phase diagrams. Apart from the topological surface states of 2M−WS2 near Γ that originated from the strong topological order, using angle-resolved photoemission spectroscopy, we discover additional Rashba-split states on the surfaces of both 2M−WS2 and 2M−WSe2, which extend in large momentum-energy regions. First-principles calculations well reproduce these states and attribute them to the weak topological orders. The calculations further indicate that the surface state connecting configurations are tunable under moderate pressure, suggesting that 2M−WS2 and WSe2 are promising platforms to study topological phase transition and explore topological superconductivity.

关键词： Photoacoustic spectroscopy

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Passive Detection Experiment of UAV Based on 5G New Radio Signal

Passive Detection Experiment of UAV Based on 5G New Radio Si...

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Progress in Electromagnetic Research Symposium (PIERS)

作者： Xiaofeng Ai Linyu Zhang Yuqing Zheng Feng Zhao State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System National University of Defence Technology China

ISBN: (纸本)9781665409889

In response to the urgent need for drone detection, a proposal using 5G New Radio (NR) signals for drone detection was proposed combined with the deployment status of 5G base stations. The characteristics of 5G NR signals and their advantages in drone detection were analyzed, and the range-Doppler two-dimensional detection and tracking processing procedure was designed with a multichannel receiver station. The outfield experiment of Unmanned Aerial Vehicle (UAV) detection was carried out through the experimental system and the results initially verified the feasibility of using 5G NR signals for UAVs detection.

关键词： Passive radar Receivers Object detection Autonomous aerial vehicles New Radio Radar tracking Proposals

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Thermal Analysis of Power Cable in Tunnel Considering Different Laying Conditions

Thermal Analysis of Power Cable in Tunnel Considering Differ...

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Power and Energy Engineering (ICPEE), International Conference on

作者： Hui Zhao Zhanlong Zhang Yongye Wu Yu Yang Zijian Dong State Key Laboratory of Power Transmission Equipment & System Security and New Technology School of Electrical Engineering Chongqing University Chongqing China Chengdu Power Supply Company State Grid Sichuan Power Supply Company Chengdu China

ISBN: (纸本)9781665464765

The thermal analysis of the power cable in the tunnel is important to evaluate ampacity, improve service life and ensure operation safety. However, the existing research mainly focuses on the influence of installation mode and installation position on the hottest cable and is less concerned about other cables. This paper establishes the temperature calculation model based on Ohm's law and thermal-flow coupling field, considering power cables laid in free air and closed space. The variation rules and influence factors of cable temperature under rated load conditions and different laying conditions are analyzed. The results show that the operation temperature is related to the proximity effect, heat radiation effect, and heat convection effect between cables and other facilities. When the cable is close to other facilities, the maximum temperature deviation is more than 7.0 K. With the increase in distance, the interaction between cables and other facilities gradually attenuates, and the temperature tends to be the condition of the single cable laid in free air. The research results provide suggestions for the modeling method selection of numerical analysis of cable temperature.

关键词： Heating systems Analytical models Radiation effects Temperature Power cables Atmospheric modeling Conductors

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Adsorbent exploration of CaSO4 for C4F7N/N2-based insulation devices from experimental and theoretical insights

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CSEE Journal of Power and Energy systems 2022年

作者： Xiao, Song Wang, Fengrun Cui, Hao Xia, Yalong Chen, Junyi Xie, Shijun Tang, Ju School of Electrical Engineering and Automation Wuhan University Wuhan430072 China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing400044 China State Grid Sichuan Electric Power Research Institute Sichuan610072 China

While the C4F7N is an environmental-friendly insulation gas with a strong potential to replace SF6 in the insulation devices, its decomposed species, especially C2F6, C3F8, C3F6, and CF4, perform a strong toxicity and poor insulation performance. In this paper, we proposed calcium sulfate (CaSO4) as a promising gas adsorbent to scavenge such four toxic species in order to guarantee the safe operation of C4F7N-based insulation devices. Experimental findings show that CaSO4 behaves a strong adsorption performance upon the moisture inner the devices and achieves dynamic equilibrium at about 70 h. The adsorption behavior upon four gases is in order as C2F6 > CF4 > C3F8 > C3F6 with the adsorbed gas content ranging at 1.5∼9 ppm. Theoretical results illustrate that CaSO4 (010) surface behaves physisorption upon four toxic gases with Ead ranging at -0.77 to -0.67 eV, and its electronic behavior changes are consistent with the order of QT. Both aspects indicate the strong potential of CaSO4 as a promising scavenger for moisture removal, toxic gas sweeping and safe operation of C4F7N-based insulation devices. Our study puts forward a novel adsorbent for toxic gas removal in the gas insulation devices and can stimulate some other cutting-edge researches about adsorbent exploration in this field. © 2022 China Electric Power Research Institute. All rights reserved.

关键词： Sulfur compounds

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