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Influencer identification of dynamical networks based on an information entropy dimension reduction method

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Chinese Physics B 2024年第4期33卷 375-384页

作者：段东立纪思源袁紫薇 school of Information and control engineering Xi'an University of Architecture and TechnologyXi'an 710311China school of Mechanical engineering Northwestern Polytechnical UniversityXi'an 710072China

Identifying critical nodes or sets in large-scale networks is a fundamental scientific problem and one of the key research directions in the fields of data mining and network science when implementing network attacks, defense, repair and *** methods usually begin from the centrality, node location or the impact on the largest connected component after node destruction, mainly based on the network ***, these algorithms do not consider network state *** applied a model that combines a random connectivity matrix and minimal low-dimensional structures to represent network *** using mean field theory and information entropy to calculate node activity,we calculated the overlap between the random parts and fixed low-dimensional parts to quantify the influence of node impact on network state changes and ranked them by *** applied this algorithm and the proposed importance algorithm to the overall analysis and stratified analysis of the *** neural *** observed a change in the critical entropy of the network state and by utilizing the proposed method we can calculate the nodes that indirectly affect muscle cells through neural layers.

关键词： dynamical networks network influencer low-dimensional dynamics network disintegration

Multimode Design and Analysis of an Integrated Leg-Arm Quadruped Robot with Deployable Characteristics

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Chinese Journal of Mechanical engineering 2024年第3期37卷 41-61页

作者： Fuqun Zhao Yifan Wu Xinhua Yang Xilun Ding Kun Xu Sheng Guo Xiaodong Jin school of Mechanical engineering and Automation Beihang UniversityBeijing 100191China school of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China

To improve locomotion and operation integration, this paper presents an integrated leg-arm quadruped robot(ILQR) that has a reconfigurable joint. First, the reconfigurable joint is designed and assembled at the end of the legarm chain. When the robot performs a task, reconfigurable configuration and mode switching can be achieved using this joint. In contrast from traditional quadruped robots, this robot can stack in a designated area to optimize the occupied volume in a nonworking state. Kinematics modeling and dynamics modeling are established to evaluate the mechanical properties for multiple modes. All working modes of the robot are classified, which can be defined as deployable mode, locomotion mode and operation mode. Based on the stability margin and mechanical modeling, switching analysis and evaluation between each mode is carried out. Finally, the prototype experimental results verify the function realization and switching stability of multimode and provide a design method to integrate and perform multimode for quadruped robots with deployable characteristics.

关键词： Quadruped robot Multimode design Mode switching Locomotion Operation

Cooperative decision-making algorithm with efficient convergence for UCAV formation in beyond-visual-range air combat based on multi-agent reinforcement learning

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Chinese Journal of Aeronautics 2024年第8期37卷 311-328页

作者： Yaoming ZHOU Fan YANG Chaoyue ZHANG Shida LI Yongchao WANG school of Aeronautic science and engineering Beihang UniversityBeijing 100191China Key Laboratory of Industrial control Technology Institute of Cyber-Systems and ControlZhejiang UniversityHangzhou 310027China

Highly intelligent Unmanned Combat Aerial Vehicle(UCAV)formation is expected to bring out strengths in Beyond-Visual-Range(BVR)air *** Multi-Agent Reinforcement Learning(MARL)shows outstanding performance in cooperative decision-making,it is challenging for existing MARL algorithms to quickly converge to an optimal strategy for UCAV formation in BVR air combat where confrontation is complicated and reward is extremely sparse and *** to solve this problem,this paper proposes an Advantage Highlight Multi-Agent Proximal Policy Optimization(AHMAPPO)***,at every step,the AHMAPPO records the degree to which the best formation exceeds the average of formations in parallel environments and carries out additional advantage sampling according to ***,the sampling result is introduced into the updating process of the actor network to improve its optimization ***,the simulation results reveal that compared with some state-of-the-art MARL algorithms,the AHMAPPO can obtain a more excellent strategy utilizing fewer sample episodes in the UCAV formation BVR air combat simulation environment built in this paper,which can reflect the critical features of BVR air *** AHMAPPO can significantly increase the convergence efficiency of the strategy for UCAV formation in BVR air combat,with a maximum increase of 81.5%relative to other algorithms.

关键词： Unmanned combat aerial vehicle(UCAV)formation Decision-making Beyond-visual-range(BVR)air combat Advantage highlight Multi-agent reinforcement learning(MARL)

Thermal-hydraulic performance analysis and multi-objective optimization of a microchannel with staggered semi-elliptical ribs

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science China Technological sciences 2024年第10期67卷 3152-3167页

作者： CUI Pan LIU Wei LIU ZhiChun school of Energy and Power engineering Huazhong University of Science and Technology

To enhance the cooling capacity of traditional microchannels for high heat flux electronic devices,a microchannel design with staggered semi-elliptical ribs is proposed in this *** numerical simulations,the flow characteristics of the designed microchannel are compared with those of a smooth one,and the effects of rib width（Wr）,rib height（Hr）,and rib length（Lr）,on the thermal-hydraulic performance are investigated under laminar flow *** results show that the periodically arranged ribs induce periodic vortices within the microchannel,effectively promoting fluid mixing and enhancing heat *** Hrhave similar effects on microchannel performance,with an increase in them leading to an enhanced thermal performance at the expense of deteriorated hydraulic ***,Lrhas a comparatively weaker influence,with both the heat transfer and flow resistance initially growing with increasing Lrand then *** strike a balance between the two performances,a multi-objective optimization on the three geometrical parameters is conducted at a Reynolds number（Re） *** with simulation data,artificial neural networks are trained as surrogate models,and a multi-objective genetic algorithm is employed to derive the Pareto *** the TOPSIS decision-making method,an optimal compromise solution is determined as Wr=0.2415 mm,Hr=0.0976 mm,and Lr=0.6486 *** testing on the optimized microchannel reveals that it exhibits high heat transfer,middle flow resistance,and excellent overall performance,with the performance evaluation criterion（PEC） falling between 1.572 and 1.723 within the Re range of 220–660.

关键词： heat transfer enhancement microchannel semi-elliptical rib numerical simulation multi-objective optimization

Recent progress of two-dimensional metal-base catalysts in urea oxidation reaction

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Rare Metals 2024年第8期43卷 3607-3633页

作者： Qi-Xiang Huang Fang Wang Yong Liu Bi-Ying Zhang Fang-Ya Guo Zhong-Qiu Jia Hao Wang Tian-Xiang Yang Hai-Tao Wu Feng-Zhang Ren Ting-Feng Yi school of Materials science and engineering Henan University of Science and TechnologyLuoyang 471000China school of Environmental engineering and Chemistry Luoyang Institute of Science and TechnologyLuoyang 471023China Henan Province International Joint Laboratory of Materials for Solar Energy Conversion and Lithium Sodium Based Battery Luoyang 471023China school of Chemistry and Life sciences Suzhou University of Science and TechnologySuzhou 215009China school of Materials science and engineering Northeastern UniversityShenyang110819China

Urea oxidation reaction(UOR)is an auxiliary water electrolysis hydrogen production technology developed in recent years to replace oxygen evolution reaction and reduce energy consumption,which can produce hydrogen more efficiently by low theoretical potential,reduce the average cost of electrochemical hydrogen production,and is a frontier research hotspot for renewable hydrogen ***-dimensional(2D)nanomaterials as electrocatalysts have many favorable potential,such as it can effectively reduce the resistivity of materials and increase the specific surface area with *** paper reviews the application of 2D materials in UOR in alkaline *** a cross-sectional comparison of various material performance data including overpotential,Tafel slope,electrochemical active surface area(ECSA)and it stability test was conducted,which could illustrate the differences between materials composed of different *** addition,the main challenges hindering the progress of research on 2D materials in urea electrocatalysis processes and promising materials in this field in future are summarized and *** is believed that this review will contribute to designing and analyzing highperformance 2D urea electrocatalysts for water splitting.

关键词： Water splitting Urea oxidation reaction Two-dimensional Transition metal compounds Noble/non-noble metals

Tunable topological polaritons by dispersion tailoring of an active metasurface

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Advanced Photonics 2024年第4期6卷 59-69页

作者： Shaojie Wang Ke Chen Shufang Dong Tian Jiang Junming Zhao Yijun Feng Nanjing University School of Electronic Science and EngineeringNanjingChina

Hyperbolic polaritons are known to exist in materials with extreme anisotropy,exhibiting exotic optical properties that enable a plethora of unusual phenomena in the fields of polaritonics and ***,achieving simultaneous low-dimensionality,high-speed controllability,and on-demand reconfigurability of the polaritons remains unexplored despite their excellent potential in light-matter interactions,photonic integrated circuits,and optoelectronic ***,we propose a metasurface approach to integrating artificially engineered electromagnetic anisotropy with fast-controllable electronic elements,offering a new route to realize active topological *** showcase the proposed reconfigurable metasurface can support real-time transitions of designer polaritons from elliptical to flat,and then to hyperbolic and circular isofrequency ***,the in-plane surface wavefront undergoes the transitions from convex to collimating,concave,and eventually back to *** exploiting the topological variations in polariton dispersions,we observe intriguing phenomena of controllable field canalization and tunable planar ***,we report the concept of a planar reconfigurable integrated polariton circuit by spatially tailoring the distributions of polariton isofrequency contours,unveiling rich dispersion engineering possibilities and active control *** may provide an inspiring platform for developing planar active plasmonic devices with potential applications in subdiffraction-resolution imaging,sensing,and information processing.

关键词： topological transitions hyperbolic metasurface anisotropic polaritons active tuning dispersion engineering

Remnants and fragments of the subducted paleo-Pacific plate:Constraints from geochemistry and geophysics

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science China Earth sciences 2024年第10期67卷 3041-3061页

作者： Xisheng XU Zhouchuan HUANG Dingsheng JIANG Gang ZENG Li-Qun DAI State Key Laboratory for Mineral Deposits Research School of Earth Sciences and EngineeringNanjing UniversityNanjing 210023China school of Earth and Space sciences University of Science and Technology of ChinaHefei 230026China

The subduction and rollback of the paleo-Pacific plate during Mesozoic time was the key engine for the evolution of the continental margin in eastern China. It led to lateral accretion of continental crust in Northeast China, lithospheric destruction beneath the North China Craton, and the generation of huge volumes of felsic magmatic rocks in South China. This had a profound influence on deep material cycles and the evolution of epigenetic environmental systems along the continental margin of East Asia. To fully understand the transformation of the dynamic mechanism during the subduction and rollback of the paleoPacific plate, we have attempted to trace the remnants and fragments of the subducted paleo-Pacific plate at great depths. Such remnants in both temporal and spatial dimensions can be tracked by using geochemical and geophysical approaches. Studies of the trace elements, Mg-Zn isotopes and Os-Nd-Hf-Pb-O isotopes in continental basalts from eastern China reveal a significant number of the remnants of subduction of the paleo-Pacific plate, and the initial subduction can be traced back to the Early Jurassic. Large-scale geophysical imaging unveils a multitude of high-velocity anomalies in the lower mantle of East ***, many high-velocity bodies, aptly referred to as “slab graveyards”, are nestled at the base of the lower mantle. Numerous isolated high-velocity anomalies are also present in the upper part of the lower mantle, creating conduits for the descent of the subducted slabs into the lower mantle. However, a resolution of the remnants for the subducted slabs within the lower mantle are quite low. Consequently, their impact on the lower mantle's dynamics is yet to be thoroughly investigated. Finally, the presently observed big mantle wedge(BMW) in East Asia has developed through subduction of the Pacific plate in the ***, following the rollback of the paleo-Pacific plate(began at ~145 Ma), a Cretaceous BMW system would also form above

关键词： Paleo-Pacific plate Big mantle wedge Late Mesozoic Remnants and fragments Geochemistry Geophysics

Rethinking attribute localization for zero-shot learning

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science China(Information sciences) 2024年第7期67卷 184-196页

作者： Shuhuang CHEN Shiming CHEN Guo-Sen XIE Xiangbo SHU Xinge YOU Xuelong LI school of Electronic Information and Communication Huazhong University of Science and Technology school of Computer science and engineering Nanjing University of Science and Technology school of Artificial Intelligence Optics and Electronics Northwestern Polytechnical University

Recent advancements in attribute localization have showcased its potential in discovering the intrinsic semantic knowledge for visual feature representations, thereby facilitating significant visual-semantic interactions essential for zero-shot learning(ZSL). However, the majority of existing attribute localization methods heavily rely on classification constraints, resulting in accurate localization of only a few attributes while neglecting the rest important attributes associated with other classes. This limitation hinders the discovery of the intrinsic semantic relationships between attributes and visual features across all *** address this problem, we propose a novel attribute localization refinement(ALR) module designed to enhance the model's ability to accurately localize all attributes. Essentially, we enhance weak discriminant attributes by grouping them and introduce weighted attribute regression to standardize the mapping values of semantic attributes. This module can be flexibly combined with existing attribute localization *** experiments show that when combined with the ALR module, the localization errors in existing methods are corrected, and state-of-the-art classification performance is achieved.

关键词： zero-shot learning attention mechanism attribute localization image classification

Sawtooth-enhanced bend sensor for gesture recognition

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science China(Technological sciences) 2024年第6期67卷 1727-1736页

作者： BAI YanRu ZHANG ZiHang WANG HaoYu GUO Rui LI XiSheng school of Automation and Electrical engineering University of Science and Technology BeijingBeijing100083China school of Advanced engineering University of Science and Technology BeijingBeijing100083China school of Precision Instrument and Opto-Electronics engineering Tianjin UniversityTianjin300072China school of Computer and Communication engineering University of Science and Technology BeijingBeijing100083China

Gesture recognition has diverse application prospects in the field of human-computer ***,gesture recognition devices based on strain sensors have achieved remarkable results,among which liquid metal materials have considerable advantages due to their high tensile strength and *** improve the detection sensitivity of liquid metal strain sensors,a sawtooth-enhanced bending sensor is proposed in this *** with the results from previous studies,the bending sensor shows enhanced resistance *** addition,combined with machine learning algorithms,a gesture recognition glove based on the sawtooth-enhanced bending sensor is also fabricated in this study,and various gestures are accurately *** the fields of human-computer interaction,wearable sensing,and medical health,the sawtooth-enhanced bending sensor shows great potential and can have wide application prospects.

关键词： liquid metal bending sensor gesture recognition machine learning