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Chinese Journal of Aeronautics 2024年第3期37卷 417-439页

作者： Dongyang SHANG Xiaopeng LI meng YIN Fanjie LI School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Shenzhen Institute of Advanced Technology Chinese Academy of SciencesShenzhen 518055China

In space operation,flexible manipulators and gripper mechanisms have been widely used because of light weight and ***,the vibration caused by slender structures in manipulators and the parameter perturbation caused by the uncertainty derived from grasping mass variation cannot be *** existence of vibration and parameter perturbation makes the rotation control of flexible manipulators difficult,which seriously affects the operation accuracy of ***’s more,the complex dynamic coupling brings great challenges to the dynamics modeling and vibration *** solve this problem,this paper takes the space flexible manipulator with an underactuated hand(SFMUH)as the research *** dynamics model considering flexibility,multiple nonlinear elements and disturbance torque is established by the assumed modal method(AMM)and Hamilton’s principle.A dynamic modeling simplification method is proposed by analyzing the nonlinear ***’s more,a sliding mode control(SMC)method combined with the radial basis function(RBF)neural network compensation is ***,the control law is designed using a saturation function in the control method to weaken the chatter *** the help of neural networks to identify the uncertainty composition in the SFMUH,the tracking accuracy is *** results of ground control experiments verify the advantages of the control method for vibration suppression of the SFMUH.

关键词： Space flexible manipulator RBF neural network Underactuated hand Dynamic models Model simplification

Multi-Robot Collaborative Hunting in Cluttered Environments With Obstacle-Avoiding Voronoi Cells

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1643-1655页

作者： meng Zhou Zihao Wang Jing Wang Zhengcai Cao the School of Electrical and Control Engineering North China University of TechnologyBeijing 100144China IEEE the College of Information Science and Technology Beijing University of Chemical TechnologyBeijing 100029China

This work proposes an online collaborative hunting strategy for multi-robot systems based on obstacle-avoiding Voronoi cells in a complex dynamic environment. This involves firstly designing the construction method using a support vector machine(SVM) based on the definition of buffered Voronoi cells(BVCs). Based on the safe collision-free region of the robots, the boundary weights between the robots and the obstacles are dynamically updated such that the robots are tangent to the buffered Voronoi safety areas without intersecting with the obstacles. Then, the robots are controlled to move within their own buffered Voronoi safety area to achieve collision-avoidance with other robots and obstacles. The next step involves proposing a hunting method that optimizes collaboration between the pursuers and evaders. Some hunting points are generated and distributed evenly around a circle. Next, the pursuers are assigned to match the optimal points based on the Hungarian ***, a hunting controller is designed to improve the containment capability and minimize containment time based on collision risk. Finally, simulation results have demonstrated that the proposed cooperative hunting method is more competitive in terms of time and travel distance.

关键词： Dynamic obstacle avoidance multi-robot collaborative hunting obstacle-avoiding Voronoi cells task allocation

双向赋予:代表身份与党政干部行为的相互激励分析

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国家现代化建设研究 2023年第1期2卷 121-137页

作者：孟天广黄种滨清华大学政治学系北京100084

代表制度是国家治理体系的重要制度,越来越多的研究探讨了代表机构及代表在国家治理中的作用。然而,学界关于代表身份如何影响我国干部的政治态度和政治行为的研究较少。我国政治制度中有人民代表大会和党员代表大会等多种代表制度,其... 详细信息

代表制度是国家治理体系的重要制度,越来越多的研究探讨了代表机构及代表在国家治理中的作用。然而,学界关于代表身份如何影响我国干部的政治态度和政治行为的研究较少。我国政治制度中有人民代表大会和党员代表大会等多种代表制度,其中具有代表身份的党政干部占一定比例。因此,代表身份与干部行为的关系就成为理解社会主义民主的重要命题。本文提出“双向赋予”理论以理解代表制度的治理意涵,这一制度安排既赋能代表制度,又赋责党政机关,发挥着强化干部人民观、促进政民互动和优化议程设置的政治功能。笔者对全国范围内1604名地方干部开展问卷调查,并使用熵平衡法分析担任代表职务后党政干部的政治态度和政治行为变化,发现拥有代表身份的党政干部在政治态度上具有更加坚定的人民观和先锋队意识,认为自身代表人民群众利益;在政治行为上扎实践行党的群众路线,同时兼顾人民群众诉求和上级安排,积极与群众保持密切联系,在决策动议和方案选择中会更多考虑民意。

关键词：干部代表代表身份政治态度政治行为

Seismicity changes and numerical simulation of coseismic deformation following the 2022 M_(s)6.8 Luding earthquake in Sichuan,China

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Science China Earth Sciences 2024年第8期67卷 2507-2521页

作者： Qiu meng Zitao WANG Huai ZHANG Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China Institute of Earthquake Forecasting China Earthquake AdministrationBeijing 100036China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China Beijing Yanshan Earth Critical Zone National Research Station Beijing 101408China

The Xianshuihe fault is a major tectonic boundary between the Sichuan-Yunnan rhombic and Bayanhar blocks in Southwest *** an average left-lateral strike-slip movement of 10–15 mm/yr,it is a fast-moving strike-slip continental *** September 5,2022,the Ms6.8 Luding earthquake occurred along the Moxi segment of the Xianshuihe fault,reaching a maximum intensity of IX and resulting in a significant number of casualties and severe property *** earthquake broke the long-standing seismic quiescence of the Xianshuihe fault,which lasted for more than 40 years,and was followed by a significant number of *** outstanding question is how the behavior of the Xianshuihe fault and major earthquakes changed following this *** this study,we examined the changes in regional seismicity following the Luding earthquake and identified the potential for future strong earthquakes along the Xianshuihe *** used a finite element numerical method to simulate the environment of the seismogenic fault and its adjacent *** addition,we used the coseismic slip model of the Luding earthquake with the split-node method to calculate how the stress and strain fields in the surrounding area were affected by the2022 *** stress changes were resolved in the main faults,and the seismicity of adjacent faults was analyzed in conjunction with the observed seismic *** results indicate that regional tectonic movement primarily occurred to the southeast along the Moxi *** stress field is approximately north-south in tension and east-west in *** in the stress field in the epicentral region of the Luding earthquake exceeded 1 *** maximum displacement of the coseismic deformation field was concentrated between Moxi town and Tuanjie village,and the Coulomb stress of the fault zone in this region experienced the largest ***,the b-value of the Gutenberg-Richter magnitude-frequency relationship at the epicenter a

关键词： Luding earthquake Seismicity Coulomb failure stress change Finite element numerical simulation

(g,e)-Symmetric Rings

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Algebra Colloquium 2024年第2期31卷 263-270页

作者： Fanyun meng Junchao Wei Nanqing Ding School of Mathematics Yangzhou UniversityYangzhouJiangsu 225002China 不详

Let R be a ring and e,g in E(R),the set of idempotents of *** R is called(g,e)-symmetric if abc=0 implies gacbe=0 for any a,b,c∈***,R is an e-symmetric ring if and only if R is a(1,e)-symmetric ring;in particular,R is a symmetric ring if and only if R is a(1,1)-symmetric *** show that e∈E(R)is left semicentral if and only if R is a(1−e,e)-symmetric ring;in particular,R is an Abel ring if and only if R is a(1−e,e)-symmetric ring for each e∈E(R).We also show that R is(g,e)-symmetric if and only if ge∈E(R),geRge is symmetric,and gxye=gxeye=gxgye for any x,y∈*** e-symmetric rings,we construct some new classes of rings.

关键词： idempotent (g,e)-symmetric ring Abel ring left semicentral

Restricted Arc-Connectivity of Harary Digraphs

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Journal of the Operations Research Society of China 2024年第2期12卷 540-547页

作者： Jun-Hao Zhang Ji-Xiang meng College of Mathematics and System Science Xinjiang UniversityUrumqi 830046XinJiangChina

The h-restricted arc-connectivity of a digraph is an important parameter to measure fault-tolerance of interconnection *** paper determines that the h-restricted arc-connectivity of the Harary digraph D=G(n;1,2,.:,k)i... 详细信息

关键词： Restricted arc-connectivity λ_(h)(D) Super-λ_(h) λ_(h)-Atom λ_(h)-Superatom

Restoring cosmological concordance with axion-like early dark energy and dark matter characterized by a constant equation of state?

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Communications in Theoretical Physics 2024年第7期76卷 74-82页

作者： Yan-Hong Yao Xin-He meng School of Physics and Astronomy Sun Yatsen University 2 Daxue RoadTangjiaZhuhaiChina School of Physics Nankai University 94 Weijin RoadNankaiTianjinChina

The Hubble tension persists as a challenge in *** early dark energy(EDE)models,initially considered the most promising for alleviating the Hubble tension,fall short of addressing the issue without exacerbating other tensions,such as the S_(8)*** that a negative dark matter(DM)equation of state(EoS)parameter is conducive to reduce the value of the σ_(8)parameter,we extend the axion-like EDE model in this paper by replacing the cold dark matter(CDM)with DM characterized by a constant EoS w_(dm)(referred to as WDM hereafter).We then impose constraints on this axion-like EDE extension model,along with three other models:the axion-like EDE model,ΛWDM,and Λ*** constraints are derived from a comprehensive analysis incorporating data from the Planck 2018 cosmic microwave background,baryon acoustic oscillations,and the Pantheon compilation,as well as a prior on H_(0)(i.e.H_(0)=73.04±1.04,based on the latest local measurement by Riess et al)and a Gaussianized prior on S_(8)(i.e.S_(8)=0.766±0.017,determined through the joint analysis of KID1000+BOSS+2dLenS).We find that although the new model maintains the ability to alleviate the Hubble tension to~1.4σ,it still exacerbates the S_(8)tension to a level similar to that of the axion-like EDE model.

关键词： Hubble tension early dark energy noncold dark matter S8 tension

Integrating Neighborhood Geographic Distribution and Social Structure Influence for Social Media User Geolocation

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Computer Modeling in Engineering & Sciences 2024年第9期140卷 2513-2532页

作者： meng Zhang Xiangyang Luo Ningbo Huang Key Laboratory of Cyberspace Situation Awareness of Henan Province Zhengzhou450001China State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou450001China

Geolocating social media users aims to discover the real geographical locations of users from their publicly available data,which can support online location-based applications such as disaster alerts and local content *** relationship-based methods represent a classical approach for geolocating social ***,geographically proximate relationships are sparse and challenging to discern within social networks,thereby affecting the accuracy of user *** address this challenge,we propose user geolocation methods that integrate neighborhood geographical distribution and social structure influence(NGSI)to improve geolocation ***,we propose a method for evaluating the homophily of locations based on the k-order neighbor-hood geographic distribution(k-NGD)similarity among *** are notable differences in the distribution of k-NGD similarity between location-proximate and non-location-proximate *** this distinction,we filter out non-location-proximate social relationships to enhance location homophily in the social *** better utilize the location-proximate relationships in social networks,we propose a graph neural network algorithm based on the social structure *** algorithm enables us to perform a weighted aggregation of the information of users’multi-hop neighborhood,thereby mitigating the over-smoothing problem of user features and improving user geolocation *** results on real social media dataset demonstrate that the neighborhood geographical distribution similarity metric can effectively filter out non-location-proximate social ***,compared with 7 existing social relationship-based user positioning methods,our proposed method can achieve multi-granularity user geolocation and improve the accuracy by 4.84%to 13.28%.

关键词： User geolocation social media neighborhood geographic distribution structure influence

Modular Synthesis of Multi-substituted Cyclobutanones Enabled by Oxyallyl Cations

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Chinese Journal of Chemistry 2024年第5期42卷 459-463页

作者： meng Wang Zhonggui Wang Ping Lu Research Center for Molecular Recognition and Synthesis Department of ChemistryFudan University220 Handan LuShanghai200433 China Present address: Department of Cancer Biology Dana-Farber Cancer Institute Department of Biological Chemistry and Molecular Pharmacology Harvard Medical SchoolBostonMA 02115USA

Stereoselective synthesis of multi-substituted cyclobutanes with different substituents is still a daunting challenge in organic *** report here a practical and facile approach to synthesizing all-trans 2,3,4-trisubstituted cyclobutanones from readily available *** substitution reaction proceeds smoothly via oxyallyl cation intermediates under mild basic *** transformation to the synthesis of 1,2,3,4-tetrasubstituted cyclobutanes was also explored.

关键词： Diastereoselectivity Modular synthesis Nucleophilic substitution Organohalides Oxyallyl cation Precision functionalization Strained molecules 1,2,3,4-Tetrasubstituted cyclobutanes

Relativistic configuration-interaction density functional theory:Nonaxial effects on nuclear ββ decay

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Science Bulletin 2024年第13期69卷 2017-2020页

作者： Yakun Wang Pengwei Zhao Jie meng State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China

Nuclear ββ decay is a second-order weak process in which an even-even nucleus decays to its neighboring even-even nucleus by turning two neutrons to two protons while emitting two electrons.A nucleus undergoes such ... 详细信息

关键词： decay neighboring interaction