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AstroPose:Astronaut pose estimation using a monocular camera during extravehicular activities

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Science China(Technological Sciences) 2024年第6期67卷 1933-1945页

作者： LIU ZiBin LI You WANG ChunHui LIU Liang GUAN BangLei SHANG Yang YU QiFeng College of Aerospace Science and engineering National University of Defense TechnologyChangsha410073China Key Laboratory of Human Factors engineering China Astronaut Research and Training CenterBeijing100094China

With the completion of the Chinese space station,an increasing number of extravehicular activities will be executed by astronauts,which is regarded as one of the most dangerous activities in human space *** guarantee the safety of astronauts and the successful accomplishment of missions,it is vital to determine the pose of astronauts during extravehicular *** article presents a monocular vision-based pose estimation method of astronauts during extravehicular activities,making full use of the available observation ***,the camera is calibrated using objects of known structures,such as the spacesuit backpack or the circular handrail outside the space ***,the pose estimation is performed utilizing the feature points on the *** proposed methods are validated both on synthetic and semi-physical simulation experiments,demonstrating the high precision of the camera calibration and pose *** further evaluate the performance of the methods in real-world scenarios,we utilize image sequences of Shenzhou-13 astronauts during extravehicular *** experiments validate that camera calibration and pose estimation can be accomplished solely with the existing observation resources,without requiring additional complicated *** motion parameters of astronauts lay the technological foundation for subsequent applications such as mechanical analysis,task planning,and ground training of astronauts.

关键词： monocular camera astronaut pose estimation camera calibration

New technology for pipeline defect detection

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Science China(Technological Sciences) 2024年第4期67卷 1294-1296页

作者： NIU YanXia SUN LongXiang WANG YiXuan SHEN GuoLang SHI Yan engineering training center Beihang UniversityBeijing 102206China School of Automation Science and Electrical engineering Beihang UniversityBeijing 100191China School of Mechanical and Electronic engineering Jingdezhen Ceramic UniversityJingdezhen 333403China

Rupture and leakage of urban sewer pipes will seriously affect the daily life of urban *** detection is one of the most important segments in the assessment of pipeline health *** the continuous extension of pipeline ... 详细信息

关键词： corrosion defect pipeline

Effects of Thirty Days Isolation on Attention Networks: A Behavioral and Event-related Potential Study

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Neuroscience Bulletin 2024年第1期40卷 127-132页

作者： Jingda Feng Bin Wu Ziqing Cao Hailong Chen Tianjun Lan Haibo Qin Yusheng Shi Weifen Huang Yinghui Li Department of Aerospace Science and Technology Space Engineering UniversityBeijing 101400China China Astronaut Research and training center Beijing 100094China State Key Laboratory of Space Medicine Fundamentals and Application China Astronaut Research and Training CenterBeijing 100094China School of Psychology Shaanxi Normal UniversityXi'an 710000China

Kear Editor,Individuals in isolated,confined,and extreme environments,such as astronauts,researchers wintering over Antarctica,submarine soldiers,and participants in simulated isolation environment experiments,commonly report difficulty in focusing their attention[1,2].However,current experimental findings from studies conducted in such environments are insufficient to fully support these self-reports of reduced *** attention-demanding tasks such as simple reaction time(RT)tasks and dual tasks,including primary pursuit tracking and secondary RT,were not affected in space flight experiments[2,3].

关键词： environments submarine winter

Fast solution to the free return orbit's reachable domain of the manned lunar mission by deep neural network

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Journal of Systems engineering and Electronics 2024年第2期35卷 495-508页

作者： YANG Luyi LI Haiyang ZHANG Jin ZHU Yuehe College of Aerospace Science and engineering National University of Defense TechnologyChangsha 410073China China Astronauts Research and training center Beijing 100094China Hunan Key Laboratory of Intelligent Planning and Simulation for Aerospace Missions Changsha 410073China

It is important to calculate the reachable domain(RD)of the manned lunar mission to evaluate whether a lunar landing site could be reached by the spacecraft. In this paper, the RD of free return orbits is quickly evaluated and calculated via the classification and regression neural networks. An efficient databasegeneration method is developed for obtaining eight types of free return orbits and then the RD is defined by the orbit’s inclination and right ascension of ascending node(RAAN) at the perilune. A classify neural network and a regression network are trained respectively. The former is built for classifying the type of the RD, and the latter is built for calculating the inclination and RAAN of the RD. The simulation results show that two neural networks are well trained. The classification model has an accuracy of more than 99% and the mean square error of the regression model is less than 0.01°on the test set. Moreover, a serial strategy is proposed to combine the two surrogate models and a recognition tool is built to evaluate whether a lunar site could be reached. The proposed deep learning method shows the superiority in computation efficiency compared with the traditional double two-body model.

关键词： manned lunar mission free return orbit reachable domain(RD) deep neural network computation efficiency

Thermal heat flux distribution prediction in an electrical vehicle battery cell using finite element analysis and neural network

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Green Energy and Intelligent Transportation 2024年第3期3卷 54-62页

作者： Luttfi A.Al-Haddad Latif Ibraheem Ahmed I.EL-Seesy Alaa Abdulhady Jaber Sinan A.Al-Haddad Reza Khosrozadeh training and Workshops center University of TechnologyBaghdadIraq Mechanical engineering Department Memorial University of NewfoundlandNewfoundland and LabradorCanada Mechanical engineering Department Benha Faculty of EngineeringBenha UniversityBenhaEgypt Mechanical engineering Department University of TechnologyBaghdadIraq Civil engineering Department University of TechnologyBaghdadIraq

In terms of battery design and evaluation,Electric Vehicles(EVs)are receiving a great deal of attention as a modern,eco-friendly,sustainable transportation *** this paper,a novel battery pack is designed to maintain a uniform temperature distribution,allowing the battery to operate within its optimal temperature *** proposed battery design is part of a main channel where a portion of cool air will pass from an inlet then exit from an outlet where a uniform temperature distribution is ***,a 3-D model of a battery cell was created,followed by thermal simulation for 15C,25C,and 35C ambient *** simulation results reveal that the temperature distribution is nearly uniform,with slightly higher values in the middle portion of the cell ***,using finite element analysis(FEA),it was determined that the heat flux per unit area is nearly uniform with a slight increase at the ***,a machine learning model is proposed by utilizing a neural network(NN).Lastly,the heat flux values were predicted using the NN model that was *** model was assessed based on statistical measures where a root mean square error(RMSE)value of 0.87%was *** NN outperformed FEA in terms of time consumption with a high prediction accuracy,leveraging the potential of adopting machine learning over FEA in related operational assessments.

关键词： EV battery Thermal distribution Finite element analysis Neural network Heat flux

Numerical investigation of supercontinuum generation and optical frequency combs in Si N-based PCF with high nonlinear coefficient

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Optoelectronics Letters 2024年第3期20卷 163-170页

作者： Mohammad Reza Alizadeh Mahmood Seifouri Saeed Olyaee Faculty of Electrical engineering Shahid Rajaee Teacher Training UniversityTehranIran Nano-photonics and Optoelectronics Research Laboratory(NORLab) Shahid Rajaee Teacher Training UniversityTehranIran

In this paper, a photonic crystal fiber(PCF) with a dispersion-engineered and high nonlinear coefficient has been designed for supercontinuum generation(SCG) and frequency comb generation(FCG). The proposed PCF has a Si_(3)N_(4) rod in the core. This rod provides more optical confinement in the core by increasing the refractive index of the core. This high confinement reduces the effective mode area of PCF and thus increases the nonlinear coefficient.

关键词： optical fiber nonlinear

Layered coordination polymer with two-dimensional covalent bismuth-organic networks:Semiconductor and lithium ion storage

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Nano Research 2024年第3期17卷 2181-2185页

作者： Mu-Qing Li Yulin Cao Lei Qin Hua Cheng Weimin Yang Zhouguang Lu School of Materials Science and Environmental engineering Shenzhen Polytechnic UniversityShenzhen 518055China Industrial training center Shenzhen Polytechnic UniversityShenzhen 518055China Department of Materials Science and engineering Southern University of Science and TechnologyShenzhen 518055China Department of Chemistry Southern University of Science and TechnologyShenzhen 518055China

Single crystals of a bismuth-based coordination polymer(CP)with carboxyl-thiol ligands,[Bi(C_(8)H_(2)O_(4)S_(2))(C2H8N)]n(Bi-DSBDC-DMA,DMBDC=2,5-disulfur-1,4-dicarboxylate,DMA=dimethylamine),have been successfully synthesized.X-ray diffraction analysis reveals that Bi-DSBDC-DMA possesses a layered structure,with two-dimensional(2D)Bi-DSBDC networks alternating with layers composed of dimethylamine *** material demonstrates semiconducting properties,featuring an optical bandgap of 2.2 eV and an electrical conductivity of 2×10^(-8) S/***,electrodes based on this material exhibit a capacity of 250 mAh/g after 200 cycles for lithium-ion storage.

关键词： bismuth layer coordination polymer(CP) semiconductor lithium ion storage

High adsorption selectivity of activated carbon and carbon molecular sieve boosting CO_(2)/N_(2) and CH_(4)/N_(2) separation

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Chinese Journal of Chemical engineering 2024年第3期67卷 282-297页

作者： Siang Chen Wenling Wu Zhaoyang Niu Deqi Kong Wenbin Li Zhongli Tang Donghui Zhang The Research center of Chemical engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Flue gas and coal bed methane are two important sources of greenhouse *** swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is *** this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 *** experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric *** the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular ***,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) *** study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.

关键词： Activated carbon Carbon molecular sieve Adsorbent evaluation Adsorption equilibrium and kinetics Heat of adsorption Selectivity

Design of Resilient Sensor Networks Balancing Resilience and Efficiency

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International Journal of Disaster Risk Science 2024年第1期15卷 107-115页

作者： Sergey N.Vecherin Kiril D.Ratmanski Luke Hogewood Igor Linkov Cold Regions Research and engineering Laboratory Engineering Research and Development CenterHanoverNH 03755USA Environmental Laboratory Engineering Research and Development CenterVicksburgMS 39180USA

In recent years,the notion of resilience has been developed and applied in many technical areas,becoming exceptionally pertinent to disaster risk *** a disaster situation,accurate sensing information is the key to efficient recovery *** general,resilience aims to minimize the impact of disruptions to systems through the fast recovery of critical functionality,but resilient design may require redundancy and could increase *** this article,we describe a method based on binary linear programming for sensor network design balancing efficiency with *** application of the developed framework is demonstrated for the case of interior building surveillance utilizing infrared sensors in both twoand three-dimensional *** method provides optimal sensor placement,taking into account critical functionality and a desired level of resilience and considering sensor type and *** problem formulation,resilience requirements,and application of the optimization algorithm are described in *** of sensor locations with and without resilience requirements shows that resilient configuration requires redundancy in number of sensors and their intelligent *** tasks are successfully solved by the described method,which can be applied to strengthen the resilience of sensor networks by *** proposed methodology is suitable for large-scale optimization problems with many sensors and extensive coverage areas.

关键词： Binary linear programming Optimal sensor placement Redundant networks Resilience and efciency Resilient sensor networks