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Experimental investigation of the thermally induced vibration of a space boom section

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Science China(Physics,Mechanics & Astronomy) 2015年第4期58卷 58-66页

作者： SU XinMing ZHANG JunHui WANG Jing BI YanQiang QIE DianFu XIANG ZhiHai XUE MingDe beijing Institute of spacecraft Environment engineering College of Architecture and Civil engineering North China University of Technology Science and Technology on Reliability and Environmental engineering Laboratory Beijing Institute of Spacecraft Environment Engineering Key Laboratory of Applied Mechanics School of Aerospace Engineering Tsinghua University

Thermally induced vibration(TIV)is a typical failure of large-scale space *** paper reports a laboratory experiment that aims to investigate this unusual structural behavior of complex engineering *** the help of a Fourier finite element program,the fixing of a space boom section is well designed so that the TIV can be successfully *** the observed torsional vibration mode is different from the bending vibration mode predicted by the classic theory based on a simple beam model,it can be successfully explained by the general thermal structural interaction *** demonstrates the validity of the theoretical model and the necessity of using finite element program to analyze complex engineering structures.

关键词： thermal-structural interaction vibration experiment

A Rapid Adaptation Approach for Dynamic Air‑Writing Recognition Using Wearable Wristbands with Self‑Supervised Contrastive Learning

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Nano-Micro Letters 2025年第2期17卷 417-431页

作者： Yunjian Guo Kunpeng Li Wei Yue Nam‑Young Kim Yang Li Guozhen Shen Jong‑Chul Lee Department of Electronic Convergence engineering Kwangwoon UniversitySeoul 01897South Korea Radio Frequency Integrated Circuit(RFIC)Bio Centre Kwangwoon UniversitySeoul 01897South Korea Department of Electronic engineering Kwangwoon UniversitySeoul 01897South Korea School of Microelectronics Shandong UniversityJinan 250101People’s Republic of China State Key Laboratory of Integrated Chips and systems Fudan UniversityShanghai 200433People’s Republic of China School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081People’s Republic of China

Wearable wristband systems leverage deep learning to revolutionize hand gesture recognition in daily *** existing approaches that often focus on static gestures and require extensive labeled data,the proposed wearable wristband with selfsupervised contrastive learning excels at dynamic motion tracking and adapts rapidly across multiple *** features a four-channel sensing array composed of an ionic hydrogel with hierarchical microcone structures and ultrathin flexible electrodes,resulting in high-sensitivity capacitance *** wireless transmission from a Wi-Fi module,the proposed algorithm learns latent features from the unlabeled signals of random wrist ***,only few-shot labeled data are sufficient for fine-tuning the model,enabling rapid adaptation to various *** system achieves a high accuracy of 94.9%in different scenarios,including the prediction of eight-direction commands,and air-writing of all numbers and *** proposed method facilitates smooth transitions between multiple tasks without the need for modifying the structure or undergoing extensive task-specific *** utility has been further extended to enhance human–machine interaction over digital platforms,such as game controls,calculators,and three-language login systems,offering users a natural and intuitive way of communication.

关键词： Wearable wristband Self-supervised contrastive learning Dynamic gesture Air-writing Human-machine interaction

Review of space relative navigation based on angles-only measurements

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Astrodynamics 2023年第2期7卷 131-152页

作者： Baichun Gong Sha Wang Shuang Li Xianqiang Li Advanced Space Technology Laboratory Nanjing University of Aeronautics and AstronauticsNanjing 210016China beijing Institute of spacecraft system engineering China Academy of Space TechnologyBeijing 100094China

Relative navigation is a key enabling technology for space missions such as on-orbit servicing and space situational *** that there are several special advantages of space relative navigation using angles-only measurements from passive optical sensors,angles-only relative navigation is considered as one of the best potential approaches in the field of space relative ***,angles-only relative navigation is well-known for its range observability *** overcome this observability problem,many studies have been conducted over the past *** this study,we present a comprehensive review of state-of-the-art space relative navigation based on angles-only *** emphasis is on the observability problem and solutions to angles-only relative navigation,where the review of the solutions is categorized into four classes based on the intrinsic principle:complicated dynamics approach,multi-line of sight(multi-LOS)approach,sensor offset center-of-mass approach,and orbit maneuver ***,the fight demonstration results of angles-only relative navigation in the two projects are briefly ***,conclusions of this study and recommendations for further research are presented.

关键词： space relative navigation relative orbit determination angles-only measurement observability

CIRCULARLY POLARIZED CONTOURED BEAM ANTENNA WITH OFFSET REFLECTORARRAY FEEDS

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电子科学学刊(英文版) 1985年第2期2卷 95-102页

作者：刘振威傅振宣 Institute of spacecraft system engineering Chinese Academy of Space Technology beijing Institute of Information and Control

A mathematical model of the circularly polarized feed is developed in this *** approach,for the Jacobi-Bessel series expansion of the physical optics radiation integral studied by *** *** extended to the case of circular polarizition.A computation method for the circularly polar-ized contoured beam of the offset reflector antennas is *** numerical resultis given for effective isotropic radiated power contour-plot of the western zone coverage of Chineseterritory by the 7-element array illumination.

关键词： illumination contour reflector offset coverage coordinates circular polarized optics isotropic

Comprehensive interpretation of the Sedongpu glacier-related mass flows in the eastern Himalayan syntaxis

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Journal of Mountain Science 2022年第9期19卷 2469-2486页

作者： ZHANG Xiao-peng HU Kai-heng LIU Shuang NIE Yong HAN Yun-zhong Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China beijing Institute of spacecraft system engineering Beijing 100094China

Glacier-related mass flows(GMFs)in the high-mountain cryosphere have become more frequent in the last decade,e.g.,the 2018 Sedongpu(SDP)GMFs in the *** forcing,thermal perturbation and heavy rainfall are common triggers of the *** the exact role of seimic forcing in the GMF formation is poorly known due to scarity of observational data of real *** the evolution processes of the GMFs and the detachment of the trunk glacier in SDP are reconstructed by using remote sensing techniques,including feature-tracking of multi-source optical satellite imagery and visual *** reconstruction demonstrates that the high frequency of GMF events in SDP after the Milin earthquake on 18 November 2017 was mainly attributed to the earthquake-induced glacial stress changes and *** post-earthquake velocity of the trunk glacier is about three times of that in December 2016 and December *** median glacier-surface velocity raised to 0.32 m d-1between November 2017 and June 2018,being 14%-77%higher than that of pre-earthquake,which is initiated by the seismic forcing and then aggravated by additional loading of ice/rock avalanches,infiltration of liquid water,progressively crevassed glacier,and local compressional *** surge motion of the trunk glacier resulted from high temperature and heavy precipitation between July and September *** infer that the trunk glacier is more sensitive to the thermal perturbation after the Milin earthquake,which is the predominant cause in sudden surge *** findings reveal comprehensive mechanisms of quakeinduced,low-angle,glacial detachment and multisource-driven GMF in the Himalayas.

关键词： Glacier-related mass flow(GMF) Milin earthquake Glacial speedup Glacier detachment Ice/rock avalanche

A parallel pipeline connected-component labeling method for on-orbit space target monitoring

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Journal of systems engineering and Electronics 2022年第5期33卷 1095-1107页

作者： LI Zongling ZHANG Qingjun LONG Teng ZHAO Baojun School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China Institute of spacecraft system engineering China Academy of Space TechnologyBeijing 100094China Institute of Remote Sensing Satellite China Academy of Space TechnologyBeijing 100094China

The paper designs a peripheral maximum gray differ-ence(PMGD)image segmentation method,a connected-compo-nent labeling(CCL)algorithm based on dynamic run length(DRL),and a real-time implementation streaming processor for *** it verifies the function and performance in space target monitoring scene by the carrying experiment of Tianzhou-3 cargo spacecraft(TZ-3).The PMGD image segmentation method can segment the image into highly discrete and simple point tar-gets quickly,which reduces the generation of equivalences greatly and improves the real-time performance for *** parallel pipeline design,the storage of the streaming processor is optimized by 55%with no need for external me-mory,the logic is optimized by 60%,and the energy efficiency ratio is 12 times than that of the graphics processing unit,62 times than that of the digital signal proccessing,and 147 times than that of personal *** the results of 8756 images completed on-orbit,the speed is up to 5.88 FPS and the target detection rate is 100%.Our algorithm and implementation method meet the requirements of lightweight,high real-time,strong robustness,full-time,and stable operation in space irradia-tion environment.

关键词： Tianzhou-3 cargo spacecraft(TZ-3) connected-component labeling(CCL)algorithms parallel pipeline processing on-orbit space target detection streaming processor

Numerical Investigation of Jet Impingement Cooling with Supercritical Pressure Carbon Dioxide in a Multi-Layer Cold Plate during High Heat Flux

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Journal of Thermal Science 2023年第1期32卷 237-253页

作者： WEN Yaming LI Yulong LI Jingqi YU Xin-Gang National Key Laboratory of Science and Technology on Aero Engines Aero-Thermodynamics&Collaborative Innovation Center for Advanced Aero-Engine School of Energy and Power EngineeringBeihang UniversityBeijing 100191China beijing Institute of spacecraft system engineering Beijing 100094China

Jet impingement cooling with supercritical pressure carbon dioxide in a multi-layer cold plate during the heat flux of 400 W/cm_(2) is investigated *** generation and distribution of pseudocritical fluid with the high specific heat of supercritical pressure carbon dioxide and the mechanism of the heat transfer enhancement led by the high specific heat are *** a given nozzle diameter,the effects of the geometric parameters of a multi-layer cold plate such as the relative nozzle-to-plate distance,relative plate thickness,and relative upper fluid thickness on the average heat transfer coefficient are *** results show that the target surface is cooled effectively with supercritical pressure carbon dioxide jet impingement *** the radial distance is less than 6 mm,the maximum wall temperature is 368 K,which is 30 K lower than the maximum junction temperature for a silicon-based insulated gate bipolar transistor,a typical electronic power *** is a pseudocritical fluid layer near the target surface,where specific heat reaches above 34 kJ/(kg·K)*** drastic rise of the specific heat leads to obvious heat transfer *** a certain range,the local heat transfer coefficient and the specific heat are linearly correlated and Stanton number remains constant over this *** heat transfer coefficient is at a maximum when the relative nozzle-to-plate distance is *** the relative plate thickness increases from 0.5 to 3.5 or the relative upper fluid thickness increases from 0.5 to 2.5,the average heat transfer coefficient decreases monotonically.

关键词： high heat flux jet impingement cooling supercritical pressure carbon dioxide heat transfer enhancement

Failure modes of lattice sandwich plate by additive-manufacturing and its imperfection sensitivity

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Acta Mechanica Sinica 2020年第2期36卷 430-447页

作者： Bin Ji Han Han Renbang Lin Hao Li Shanghai Key Laboratory of spacecraft Mechanism Shanghai 201109China Aerospace system engineering Shanghai Shanghai 201109China

Additive-manufacturing process has substantially promoted the development of lattice structure and makes it possible to fabricate complex lattice sandwich ***-plane compression load always appears in engineering,such as in the primary structure of *** order to reveal potential engineering application in future,this paper focuses on the lattice sandwich plate that is fabricated by additive-manufacturing and subjected to in-plane ***,five failure modes are proposed for lattice sandwich plate under in-plane compression,including Euler buckling,shear buckling,face sheet dimpling,face sheet wrinkling and face sheet ***,an optimization method is proposed to obtain the optimum sizes,including the panel thickness,the length of rod,the size of rod cross-section,the inclined angle of rod and the wideness ratio of ***,the in-plane compression experiment is operated after measuring the geometrical imperfection of the specimen by the optical *** method is adopted to illustrate the effect on failure behaviors caused by the imperfections of struts,face sheets and global *** introducing these imperfection,numerical result can be well agreed with experimental result and explain the failure mechanisms mostly derived from the radius imperfection for the struts.

关键词： Additive-manufacturing Lattice structure In-plane compression Failure mode Imperfection sensitivity

Two Congruent Semantics for Prolog with CUT

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Journal of Computer Science & Technology 1990年第1期5卷 82-91页

作者：朱明远 beijing Institute of system engineering

The development of a formal semantics for a given programming language can proceed in several stages. At each stage we give an alternative semantic definition of the language, and each definition embodies successively more and more implementation details. Then we formulate and prove at each stage the congruence conditions between successive definitions in the sequence. This paper presents two formal semantics for Prolog with “cut” and shows the congruence condition between them.

关键词： ENVI Prolog Two Congruent Semantics for Prolog with CUT