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Dynamic modeling and RBF neural network compensation control for space flexible manipulator with an underactuated hand

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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

(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

Seismicity changes and numerical simulation of coseismic deformation following the 2.2. 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 5,2.2.,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 the2.2. *** 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

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)is equal to n/2.for 2.h≤n/2.k=2.and n iseven,andλ_(h)(D)=g(k-1)for 2.h≤g and 3≤k≤n/2.where g is the girth of *** consequences,the super restricted arc-connectedness of Harary digraph D is obtained *** particular,for k=2.and n is even or 3≤k2.nd n can be divided by k,it can be determined that distinct positive(respectively,negative)Ah-superatoms of D are vertex disjoint for 2.h≤g.

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

The next decade of SET:from an oncoprotein to beyond

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Journal of Molecular Cell Biology 2024年第1期16卷 1-14页

作者： Han Yao meng Zhang Donglai Wang State Key Laboratory of Common Mechanism Research for Major Diseases&Department of Medical Genetics Institute of Basic Medical Sciences&School of Basic MedicineChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100005China

This year marks the fourth decade of research into the protein SET,which was discovered in *** was initially identified as an oncoprotein but later shown to be a multifaceted protein involved in regulating numerous biological processes under both physiological and pathophysiological *** dysfunction is closely associated with diseases,such as cancer and Alzheimer's *** the increasing understanding of how SET works and how it is regulated in cells,targeting aberrant SET has emerged as a potential strategy for disease *** this review,we present a comprehensive overview of the advancements in SET studies,encompassing its biological functions,regulatory networks,clinical implications,and pharmacological ***,we provide insights into the future prospects of SET research,with a particular emphasis on its promising potential in the realm of immune modulation.

关键词： SET biological process regulatory mechanism disease therapy

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 2.18 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+2.LenS).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

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

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