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Coupling Vibration of Simply-Supported Damping Beam Carrying a Moving Mass

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Acta Mechanica Solida Sinica 2022年第6期35卷 972-978页

作者： Jingjing hu Weipeng hu Chuan Xiao Zichen deng School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China School of Civil Engineering and Architecture Xi’an University of TechnologyXi’an710048China State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of China Xi’an University of TechnologyXi’an710048China China Research and Development Academy of Machinery Equipment Beijing100089China

The coupling dynamic problems,such as the vehicle-bridge interaction problem,are difficult to be analyzed.In this paper,the generalized multi-symplectic approach is employed to investigate the coupling dynamic behaviors in the vehicle-bridge interaction system.A simply-supported damping beam model carrying a moving mass is considered and the generalized multi-symplectic form with the dynamical symmetry breaking factors is deduced firstly.And then,Preissmann’s scheme is employed to discretize the generalized multi-symplectic form,and the discrete structure-preserving condition for the numerical scheme is presented.According to the discrete structure-preserving condition,the permitted moving speed of the mass with different damping factors and different time step lengths is obtained to ensure the structure-preserving properties of the numerical scheme.Finally,the effects of the damping factor of the beam and the moving speed of the mass on the vibration of the beam are investigated by Preissmann’s scheme.The main contribution of this work is to provide a structure-preserving analysis approach for the vehicle-bridge interaction problem.

关键词： Vehicle-bridge interaction Dynamical symmetry breaking Generalized multi-symplectic Hamiltonian Moving mass

Multi-Axis Attention With Convolution Parallel Block for Organoid Segmentation

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1295-1297页

作者： Pengwei hu Xun deng Feng Tan Lun hu Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of SciencesUrumqi 830011 University of Chinese Academy of Sciences Beijing 100049 Xinjiang Laboratory of Minority Speech and Language Information Processing Urumqi 830011China Merck KGaA Darmstadt 64293Germany

Dear Editor,This letter presents an organoid segmentation model based on multi-axis attention with convolution parallel *** adeptly captures dynamic dependencies within bright-field microscopy images,improving global ... 详细信息

关键词： letter convolution organo

Nitrogen incorporated nickel molybdenum sulfide as efficient electrocatalyst for overall water splitting

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Journal of Materials Science & Technology 2022年第4期99卷 270-276页

作者： Kena Wu Xiaonan Wei deng Li Peng hu Beijing Bioprocess Key Laboratory State Key Laboratory of Chemical Resource EngineeringBeijing University of Chemical TechnologyBeijing 100029China Amoy-BUCT Industrial Bio-technovation Institute Amoy 361022China Key Laboratory of Advanced Functional Materials Education Ministry of ChinaFaculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China

Developing bifunctional electrocatalysts with improved efficiency and stability in overall water splitting is of extreme importance for renewable energy utilization.In this work,an in situ N doping strategy was demonstrate to boost the efficiency and stability of nickel molybdenum sulfide both in electrocatalytic hydrogen evolution reaction and oxygen evolution reaction.Experimental and theoretical results indicate that such modification offers enriched active sites for electrochemical reaction,and further increases the kinetic driven force of water electrolysis.As a result,the N–NiMoS electrode exhibits a remarkably improved performance with rather low potential of 1.54 V to offer a current density of 10 mA cm;for overall water splitting,which is 130 mV decrease than that of pristine one.In addition,impressive electrochemical stability also reveals a 76.6%preservation of initial current density after 100 h test,which is superior than that of pristine one after 25 h test.Therefore,the potential to enhance the performance of electrocatalysts by as-proposed route promises a valuable way to develop efficient catalysts with enhanced property for electrochemical applications.

关键词： Bifunctional electrocatalyst Water splitting Nitrogen incorporation Nickel molybdenum sulfide

Restoring Vision Naturally and Noninvasively

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Neuroscience Bulletin 2021年第11期37卷 1642-1644页

作者： Chundi Wang hu deng Shenbing Kuang Department of Psychology and Research Centre of Aeronautic Psychology and Behavior Beihang UniversityBeijing 100191China Peking University huiLongGuan Clinical Medical School Beijing HuiLongGuan Hospital.Beijing 100096China State Key Laboratory of Brain and Cognitive Science Institute of PsychologyChinese Academy of SciencesBeijing 100101China

More than 200 million people across the world suffer from moderate to severe visual impairments,mostly due to retinal degeneration or damage to the eyes[1].Methods of reprogramming the cells in the eyes or electrical ... 详细信息

关键词： programming mostly damage

Mechanism of Regional Subseasonal Precipitation in the Strongest and Weakest East Asian Summer Monsoon Subseasonal Variation Years

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Journal of Ocean University of China 2022年第6期21卷 1411-1427页

作者： hu Haibo deng Yuheng FANG Jiabei WANG Rongrong CMA-NJU Joint Laboratory for Climate Prediction Studies Instituted for Climate and Global Change ResearchSchool of Atmospheric ScienceNanjing UniversityNanjing 210093China Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science and TechnologyNanjing 210044China

Using the National Center for Environment Prediction Climate Forecast System Reanalysis coupled dataset during 1979–2010,we selected four subseasonal indexes from the 16 East Asian Summer Monsoon(EASM)indexes to characterize the subseasonal variability of the entire EASM system.The strongest(1996)and weakest(1998)years of the subseasonal variation were revealed based on these subseasonal EASM indexes.Furthermore,three rainfall concentration areas were defined in East Asia,and these areas were dissected by the atmospheric midlatitude jet stream axis and the position of the Western North Pacific Subtropical High(WNPSH).Then,the subseasonal effects of the WNPSH,the South Asian High(SAH),the Mongolian Cyclone(MC),and the Boreal Summer Intraseasonal Oscillation(BSISO)on each rainfall concentration area were studied in the strongest and weakest subseasonal variation years of the EASM.During the summer of 1998,the WNPSH and the SAH were stable in the more southern region,which not only blocked the northward progression of the BSISO but also caused the MC to advance southward.Therefore,the summer of 1998 was the weakest subseasonal variability of the EASM,but with significant subseasonal precipitation episodes in the northern and central rainfall areas.However,in 1996,the BSISO repeatedly spread northward in the south rainfall area because of the weak intensities and northern positions of the WNPSH and the SAH,which caused significant subseasonal precipitation episodes.In addition,MC was blocked to the north of approximately 42°N with a weak subseasonal rainfall.

关键词： East Asian Summer Monsoon Subseasonal Western North Pacific Subtropical High Mongolian Cyclone Boreal Summer Intraseasonal Oscillation

A cluster positioning architecture and relative positioning algorithm based on pigeon fock bionics

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Satellite Navigation 2023年第1期4卷 92-112,I0004页

作者： Zhongliang deng Hang Qi Chengfeng Wu Enwen hu Runmin Wang Beijing University of Posts and Telecommunications Beijing 100876China Science and Technology on Complex System Control and Intelligent Agent Cooperative Laboratory Beijing 100074China.

Unmanned clusters can realize collaborative work,fexible confguration,and efcient operation,which has become an important development trend of unmanned platforms.Cluster positioning is important for ensuring the normal operation of unmanned clusters.The existing solutions have some problems such as requiring external system assistance,high system complexity,poor architecture scalability,and accumulation of positioning errors over time.Without the aid of the information outside the cluster,we plan to construct the relative position relationship with north alignment to adopt formation control and achieve robust cluster relative positioning.Based on the idea of bionics,this paper proposes a cluster robust hierarchical positioning architecture by analyzing the autonomous behavior of pigeon focks.We divide the clusters into follower clusters,core clusters,and leader nodes,which can realize fexible networking and cluster expansion.Aiming at the core cluster that is the most critical to relative positioning in the architecture,we propose a cluster relative positioning algorithm based on spatiotemporal correlation information.With the design idea of low cost and large-scale application,the algorithm uses intra-cluster ranging and the inertial navigation motion vector to construct the positioning equation and solves it through the Multidimensional Scaling(MDS)and Multiple Objective Particle Swarm Optimization(MOPSO)algorithms.The cluster formation is abstracted as a mixed direction-distance graph and the graph rigidity theory is used to analyze localizability conditions of the algorithm.We designed the cluster positioning simulation software and conducted localizability tests and positioning accuracy tests in diferent scenarios.Compared with the relative positioning algorithm based on Extended Kalman Filter(EKF),the algorithm proposed in this paper has more relaxed positioning conditions and can adapt to a variety of scenarios.It also has higher relative positioning accuracy,and the error does not accumulate over time.

关键词： Cluster positioning architecture Cluster relative positioning Multidimensional scaling Multiple objective particle swarm optimization Unmanned aerial vehicles positioning Localizability analysis Rigid graph

Minimum Control Energy of Spatial Beam with Assumed Attitude Adjustment Target

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Acta Mechanica Solida Sinica 2020年第1期33卷 51-60页

作者： Weipeng hu Lingjun Yu Zichen deng School of Civil Engineering and Architecture Xi’an University of TechnologyXi’an 710048China State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of China Xi’an University of TechnologyXi’an 710048China Department of Aeronautical Machinery Engineering of Army Aviation Institute Beijing 101123China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China

The dynamic analysis on the ultra-large spatial structure can be simplified drastically by ignoring the flexibility and damping of the structure.However,these simplifications will result in the erroneous estimate on the dynamic behaviors of the ultra-large spatial structure.Taking the spatial beam as an example,the minimum control energy defined by the difference between the initial total energy and the final total energy in the assumed stable attitude state of the beam is investigated by the structure-preserving method proposed in our previous studies in two cases:the spatial beam considering the flexibility as well as the damping effect,and the spatial beam ignoring both the flexibility and the damping effect.In the numerical experiments,the assumed simulation interval of three months is evaluated on whether or not it is long enough for the spatial flexible damping beam to arrive at the assumed stable attitude state.And then,taking the initial attitude angle and the initial attitude angle velocity as the independent variables,respectively,the minimum control energies of the mentioned two cases are investigated in detail.From the numerical results,the following conclusions can be obtained.With the fixed initial attitude angle velocity,the minimum control energy of the spatial flexible damping beam is higher than that of the spatial rigid beam when the initial attitude angle is close to or far away from the stable attitude state.With the fixed initial attitude angle,ignoring the flexibility and the damping effect will underestimate the minimum control energy of the spatial beam.

关键词： Spatial beam Structure-preserving method Generalized multi-symplectic Minimum control energy Hamiltonian

Recent progress on multifunctional electromagnetic interference shielding polymer composites

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Journal of Materials Science & Technology 2023年第3期134卷 106-131页

作者： Ke Tian Danrong hu Quan Wei Qiang Fu hua deng College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China Rehabilitation Medicine Center and Institute of Rehabilitation Medicine Key Laboratory of Rehabilitation Medicine in Sichuan ProvinceWest China HospitalSichuan UniversityChengdu 610041China

The explosive development of electronic devices and wireless communication technology gives rise to the issue of electromagnetic pollution,known as electromagnetic interference(EMI).The accumulation of undesirable electromagnetic radiation in space disturbs the normal function of unshielded electronic appliances and poses seriously threat to human health.Thus,the development of EMI shielding materials have emerged to solve the grim problem.Considering the complex application contexts,EMI shielding materials have evolved from traditional single-function to multi-functions to meet the ever-increasing application requirements in recent few years.This paper provides detailed insight into the current re-search status and future challenges in the advancement of polymer-based EMI shielding materials with various functions.First,the basic theory of EMI shielding,factors influencing results and the dominating characterization technologies for EMI shielding properties are summarized.Then,the comprehensive descriptions of the seven types of multifunctional EMI shields are provided with respect to their structures,fabrication methods and specific functions.Meanwhile,the corresponding critical scientific and technical issues are proposed.Based on our comprehensive analysis,the main challenges in the development of multifunctional EMI shielding materials are presented.This review aims to provide some guidance and inspire more efforts toward functional EMI shielding material research to satisfy the growing requirements for next-generation electronic systems.

关键词： Polymer-based composites Electromagnetic interference shielding Multiple losses Multifunctionality

Two-stage robust optimization of power cost minimization problem in gunbarrel natural gas networks by approximate dynamic programming

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Petroleum Science 2022年第5期19卷 2497-2517页

作者： Yi-Ze Meng Ruo-Ran Chen Tian-hu deng Department of Industrial Engineering Tsinghua UniversityBeijing100084China

In short-term operation of natural gas network,the impact of demand uncertainty is not negligible.To address this issue we propose a two-stage robust model for power cost minimization problem in gunbarrel natural gas networks.The demands between pipelines and compressor stations are uncertain with a budget parameter,since it is unlikely that all the uncertain demands reach the maximal deviation simultaneously.During solving the two-stage robust model we encounter a bilevel problem which is challenging to solve.We formulate it as a multi-dimensional dynamic programming problem and propose approximate dynamic programming methods to accelerate the calculation.Numerical results based on real network in China show that we obtain a speed gain of 7 times faster in average without compromising optimality compared with original dynamic programming algorithm.Numerical results also verify the advantage of robust model compared with deterministic model when facing uncertainties.These findings offer short-term operation methods for gunbarrel natural gas network management to handle with uncertainties.

关键词： Natural gas Gunbarrel gas pipeline networks Robust optimization Approximate dynamic programming