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24th International Vacuum Electronics Conference, IVEC 2023

作者： Cao, Yingjian Liu, Guo Ma, Yuan Wang, Yu Wang, Weijie Jiang, Wei Yau, Yelei Wang, Jianxun Luo, Yong University of Electronic Science and Technology of China Chengdu610054 China Laboratory of Electromagnetic Space Cognition and Intelligent Control Beijing100089 China

ISBN: (纸本)9781665473217

In this paper, the design and measurement of a mode-suppression circuit used in the nonlinear interaction region for a G-band gyrotron travelling wave tube (gyro-TWT) are presented. By achieving sufficient coupling losses, this circuit can effectively suppress the parasitic oscillations without affecting the operating mode, thus improving the tube stability during high power operation. The measured results agree well with the simulated results, which can provide a loss of 5.6 dB/cm to suppress the backward-wave oscillation (BWO) of the TE21 mode. This proves that the circuit can be used as a new scheme for gyro- TWTs to achieve high stability and high power. © 2023 IEEE.

关键词： Timing circuits

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Power Switching Based on Trajectory Planning and Sliding Mode control for Solid Oxide Fuel Cell Systems

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Journal of Modern Power Systems and Clean Energy 2024年第6期12卷 1968-1979页

作者： Zhen Wang Guoqiang Liu Xingbo Liu Jie Wang Zhiyang Jin Xiaowei Fu Zhuo Wang Bing Jin Zhonghua Deng Xi Li Key Laboratory of Imaging Processing and Intelligent Control of Ministry of Education School of Artificial Intelligence and AutomationHuazhong University of Science and TechnologyWuhanChina Research Institute of Huazhong University of Science and Technology in Shenzhen ShenzhenChina Hubei Huazhong Electric Power Technology Development Co. Ltd.WuhanChina School of Computer Science and Technology Wuhan University of Science and TechnologyWuhanChina School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhanChinaand he is also with the Wuhan Huamao Automation Co.Ltd.WuhanChina

To improve the safety of the solid oxide fuel cell(SOFC)systems and avoid the generation of large amounts of pollutants during power switching,this paper designs a power switching strategy based on trajectory planning and sliding mode control(TP-SMC).The design elements of the power switching strategy are proposed through simulation analysis at ***,based on the gas transmission delay time and the change of gas flow obtained from testing,trajectory planning(TP)is *** with other power switching strategies,it has been proven that the power switching strategy based on TP has significantly better control ***-thermore,considering the shortcomings and problems of TP in practical application,this paper introduces sliding mode control(SMC)on the basis of TP to improve the power switching *** final simulation results also prove that the TP-SMC can effectively suppress the impact of uncertainty in gas flow and gas transmission delay *** with TP,TP-SMC can ensure that under uncertain conditions,the SOFC system does not experience fuel starvation and temperature exceeding limit during power ***,the NOx emissions are also within the normal and acceptable *** paper can guide the power switching process of the actual SOFC sys-tems to avoid safety issues and excessive generation of NOx,which is very helpful for improving the performance and ser-vice lifeof the SOFCsystems.

关键词： Solid oxide fuel cell(SOFC)system power switching safety NOx emission trajectory planning sliding mode control

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A new active rehabilitation training mode for upper limbs based on Tai Chi Pushing Hands

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Biomimetic Intelligence & Robotics 2024年第3期4卷 82-92页

作者： Xiangpan Li Liaoyuan Li Jianhai Han Bingjing Guo Ganqin Du School of Mechatronics Engineering Henan University of Science and TechnologyLuoyang 471003China Henan Provincial Key Laboratory of Robotics and Intelligent Systems Luoyang 471003China School of Automotive Engineering Hubei University of Automotive TechnologyShiyan 442002China Hubei Key Laboratory of Automotive Power Train and Electronic Control Shiyan 442002China The First Affiliated Hospital of Henan University of Science and Technology Luoyang 471003China

Robot-assisted rehabilitation is a crucial approach to restoring motor function in the ***,the current training trajectory lacks sufficient theoretical or practical support,and the monotony of single-mode training is a *** Chi Pushing Hands,a beneficial and effective daily exercise,has been shown to improve balance function,psychological state,and motor function of the upper extremities in patients recovering from *** address these issues,we propose a new active rehabilitation training that incorporates Tai Chi Pushing Hands movements and yin-yang balance *** training trajectory and direction are encoded by the velocity field and consist of two processes:yang(push)and yin(return).During yang,the limb actively pushes the robot to move,while during yin,the limb actively follows the robot’s *** provide necessary assistance,an admittance controller with self-adaptive parameters is *** addition,we introduce two indexes,the‘Intention Angle’(ϖ)and the time ratio(Γ),to evaluate motion perception *** experiment was conducted on a 4-degree-of-freedom upper limb rehabilitation robot platform,and the subjects were separated into a familiar group and an unfamiliar *** experiment results show that the training could be completed well no matter whether the subject is familiar with Tai Chi Pushing Hands or *** parameters and the movement of the robot can be adjusted based on the interactive force to adapt to the ability of the subject.

关键词： Tai Chi Push Hands Velocity field Self-adaptive admittance Upper limb rehabilitation Active training

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Network synchronizability enhancement viaadding antagonistic interactions

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Autonomous intelligent Systems 2024年第1期4卷 1-7页

作者： Yue Song Xiaoqin Liu Dingmei Wang Pengfei Gao Mengqi Xue Shanghai Institute of Intelligent Science and Technology Tongji UniversityShanghai201210China Shanghai Research Institute for Intelligent Autonomous Systems Tongji UniversityShanghai201210China Department of Control Science and Engineering Tongji UniversityShanghai201210China National Key Laboratory of Autonomous Intelligent Unmanned Systems Tongji UniversityShanghai201210China Lanzhou Longneng Electric Power Technology Company Lanzhou730070China

We discover a“less-is-more”effect that adding local antagonistic interactions(negative edge weights)can enhance the overall synchronizability of a dynamical network *** explain this seemingly counterintuitive phenomenon,a condition is established to identify those edges the weight reduction of which improves the synchronizability index of the underlying *** further reveal that this condition can be interpreted from the perspective of resistance distance and network community *** obtained result is also verified via numerical experiments on a 14-node network and a 118-node *** brings new thoughts and inspirations to the future directions of optimal network design problems.

关键词： Synchronizability Complex network Laplacian matrix Antagonistic interaction

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Imbalanced Fault Diagnosis of key Components in spacecraft ACS via Collaborative ResNet

Imbalanced Fault Diagnosis of Key Components in Spacecraft A...

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2023 China Automation Congress, CAC 2023

作者： Ma, Shujun Mao, Zehui Liang, Hanyu Li, Shuyu College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing China Laboratory of Science and Technology on Space Intelligent Control Beijing China

ISBN: (纸本)9798350303759

In this paper, a fault diagnosis method based on Collaborative Residual Network (Collaborative ResNet) is proposed to address the problem of imbalanced fault diagnosis for key components of spacecraft attitude control system (ACS). The designed Collaborative ResNet consists of two branches, the conventional learning branch and rebalancing learning branch, which conduct representation learning and classifier learning, respectively. A new Dynamic Complementary Loss (DC Loss) is introduced in the rebalancing learning to dynamically alleviate the excessive gradient of negative samples on the few sample classes and compensate for the gradient of misdiagnosed samples, which enhances the network sensitivity to the class with few number samples. Then the features extracted by two branches are adaptively integrated through the collaborative learning strategy to combine the strengths of both approaches. The effectiveness of the proposed method was validated on the imbalanced data collected on a ground semi-physical platform. © 2023 IEEE.

关键词： Failure analysis

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RUL Prediction of Turbofan Engine Based on WGAN-Trans under Small Samples

RUL Prediction of Turbofan Engine Based on WGAN-Trans under ...

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2023 China Automation Congress, CAC 2023

作者： Qi, Chenman Mao, Zehui Liu, Wenjing College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing China Laboratory of Science and Technology on Space Intelligent Control Beijing China

ISBN: (纸本)9798350303759

The prediction of the remaining useful life of the turbofan engine of an aircraft is a very important part of its PHM. With the arrival of the era of Big data, data driven RUL prediction methods are gradually emerging, however, in the actual industry, it is often difficult to collect sufficient data to predict the RUL under deep learning which means there will be a problem of small samples. Moreover, in the early stage of degradation, it is difficult to accurately classify the health status of equipment, resulting in the inability to provide early warning before the rapid degradation of equipment performance, thus losing the significance of developing maintenance strategies in advance. To solve this problem, this paper proposes a WGAN-Trans model, which expands the data set by improving the Gener-ative adversarial network, uses the one-dimensional Convolutionl Neural Network to divide the health state, and finally uses the Transformer model to predict the RUL, which is verified on the commercial aircraft turbofan engine data set provided by NASA. The results show that the proposed model has good performance. © 2023 IEEE.

关键词： Turbofan engines

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Image motion and experimental study of a 0.1″space pointing measuring instrument for micro-vibration conditions

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Chinese Journal of Aeronautics 2023年第2期36卷 191-200页

作者： Lin LI Li YUAN Li WANG Miaomiao WANG Xiaoxue GONG Jie SUI Yanpeng WU Ran ZHENG Space Optoelectronic Measurement and Perception Lab. Beijing Institute of Control EngineeringBeijing 100190China China Academy of Space Technology Beijing 100094China Science and Technology on Space Intelligent Control Laboratory Beijing 100094China University of Chinese Academy of Sciences Beijing 100049China Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Chang Guang Satellite Technology Co. Ltd.Changchun130102China

There exists an increasing need for Milli-Arc-Seconds(MAS)accuracy pointing measurement for current and future space *** meet the 0.1″space pointing measurement accuracy requirements of spacecraft in future,the influence of spacecraft micro-vibration on a 0.1″space Pointing Measuring Instrument(SPMI)is studied.A Quasi-Zero Stiffness Device(QZSD)with adaptive adjustment and variable stroke was ***,a series of micro-vibration experiments of the SPMI were carried *** influence of the micro-vibration generated by Guidance Navigation control(GNC)attitude control components under different attitudes on the SPMI was *** spread function of image motion in micro-vibration was also ***,the changes of image motion under the micro-vibration environment were evaluated by extracting the gray centroid of the images,and the experiment processes and results are deeply *** results show that the firstorder frequency of the QZSD system is 0.114 Hz,and it is induced by a double pendulum system;the image motion of single flywheel spinning reached 0.015 pixels;whilst the image motion reached 0.03 pixels when three flywheels are combined *** latest findings provide a beneficial theoretical and technical support for the development of spacecraft with 0·1″pointing accuracy.

关键词： Image motion Micro-vibration Milli-arc-seconds Quasi-zero stiffness device space pointing measuring instrument

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High-performance self-powered ultraviolet to near-infrared photodetector based on WS_(2)/InSe van der Waals heterostructure

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Nano Research 2023年第5期16卷 7851-7857页

作者： Jinping Chen Zhen Zhang Yi Ma Jiying Feng Xiaoyu Xie Xiaoxuan Wang Aoqun Jian Yuanzheng Li Zhuxin Li Heng Guo Yizhi Zhu Qiannan Cui Zengliang Shi Chunxiang Xu State Key Laboratory of Bioelectronics School of Biological Science and Medical EngineeringSoutheast UniversityNanjing 210096China Micro Nano System Research Center Key Laboratory of Advanced Transducers and Intelligent Control System of the Ministry of Education&College of Information Engineering and ComputerTaiyuan University of TechnologyTaiyuan 030024China Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education Northeast Normal UniversityChangchun 130024China

van der Waals heterostructures(vdWHs)based on two-dimensional(2D)materials without the crystal lattice matching constraint have great potential for high-performance optoelectronic ***,a WS_(2)/InSe vdWH photodiode is proposed and fabricated by precisely stacking InSe and WS_(2)flakes through an all-dry transfer *** WS_(2)/InSe vdWH forms an n–n heterojunction with strong built-in electric field due to their intrinsic n-type semiconductor characteristics and energy-band alignments with a large Fermi level offset between WS_(2)and *** a result,the device displays excellent photovoltaic behavior with a large open voltage of 0.47 V and a short-circuit current of 11.7 nA under 520 nm light ***,a fast rising/decay time of 63/76μs,a large light on/off ratio of 105,a responsivity of 61 mA/W,a high detectivity of 2.5×10^(11) Jones,and a broadband photoresponse ranging from ultraviolet to near-infrared(325–980 nm)are achieved at zero *** study provides a strategy for developing high-performance self-powered broadband photodetectors based on 2D materials.

关键词： two-dimensional materials van der Waals heterostructure self-powered photodetector photocurrent

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A Legged Small Celestial Body Landing Mechanism:Landing Simulation and Experimental Test

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space(science & technology) 2023年第1期3卷 453-463页

作者： Zhijun Zhao Shuang Wu Jingdong Zhao Yaobing Wang Chuncheng Zhao Beijing Key Laboratory of Intelligent Space Robotic System Technology and Applications Beijing Institute of Spacecraft System EngineeringBeijing 100094China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150006China Department of Aerospace Science and Technology Polytechnic University of MilanMilan 20133Italy

Landing mechanism tends to rebound and turn over,and the stability time is long when landing on the small celestial *** landing performance in different conditions is necessary to be evaluated to guide the ***,landing performance evaluation is realized by *** factors affecting the landing performance including cardan element damping,foot anchors,retro-rocket thrust,landing slope angle,and landing attitude are analyzed.A microgravity platform is built to test the landing mechanism,and the consistency between the simulation and the experiment is *** the basis of simulation and experiment,some landing suggestions are proposed to improve the landing performance.

关键词： thrust mechanism landing

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Graphene binding on black phosphorus enables high on/off ratios and mobility

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National science Review 2024年第2期11卷 188-195页

作者： Fanrong Lin Zhonghan Cao Feiping Xiao Jiawei Liu Jiabin Qiao Minmin Xue Zhili Hu Ying Liu Huan Lu Zhuhua Zhang Jens Martin Qingjun Tong Wanlin Guo Yanpeng Liu Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education State Key Laboratory of Mechanics and Control of Mechanical Structures and Institute for Frontier Science Nanjing University of Aeronautics and Astronautics Centre for Advanced 2D Materials National University of Singapore School of Physics and Electronics Hunan University Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and MeasurementSchool of PhysicsBeijing Institute of Technology Leibniz Institute für Kristallzüchtung

Graphene is one of the most promising candidates for integrated circuits due to its robustness against short-channel effects, inherent high carrier mobility and desired gapless nature for Ohmic contact, but it is difficult to achieve satisfactory on/off ratios even at the expense of its carrier mobility, limiting its device applications. Here, we present a strategy to realize high back-gate switching ratios in a graphene monolayer with well-maintained high mobility by forming a vertical heterostructure with a black phosphorus multi-layer. By local current annealing, strain is introduced within an established area of the graphene, which forms a reflective interface with the rest of the strain-free area and thus generates a robust off-state via local current depletion. Applying a positive back-gate voltage to the heterostructure can keep the black phosphorus insulating, while a negative back-gate voltage changes the black phosphorus to be conductive because of hole accumulation. Then, a parallel channel is activated within the strain-free graphene area by edge-contacted electrodes, thereby largely inheriting the intrinsic carrier mobility of graphene in the on-state. As a result, the device can provide an on/off voltage ratio of >10～3 as well as a mobility of ～8000 cm2V-1s-1at room temperature, meeting the low-power criterion suggested by the International Roadmap for Devices and Systems.

关键词： graphene on/off ratio mobility black phosphorus reflective interface

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