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Kinematics-based four-state trajectory tracking control of a spherical mobile robot driven by a 2-DOF pendulum

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Chinese Journal of Aeronautics 2019年第6期32卷 1530-1540页

作者： Wei li Qiang zhan Robotics Institute Beihang UniversityBeijing 100083China Ecole Centrale de Pékin Beihang UniversityBeijing 100083China

Spherical mobile robot has compact structure, remarkable stability, and flexible motion,which make it have many advantages over traditional mobile robots when applied in those unmanned environments, such as outer planets. However, spherical mobile robot is a special highly under-actuated nonholonomic system, which cannot be transformed to the classic chained form. At present, there has not been a kinematics-based trajectory tracking controller which could track both the position states and the attitude states of a spherical mobile robot. In this paper, the four-state(two position states and two attitude states) trajectory tracking control of a type of spherical mobile robot driven by a 2-DOF pendulum was studied. A controller based on the shunting model of neurodynamics and the kinematic model was deduced, and its stability was demonstrated with Lyapunov’s direct method. The control priorities of the four states were allocated according to the magnification of each state tracking error in order to firstly ensure the correct tracking of the position states. The outputs(motor speeds) of the controller were regulated according to the maximum speeds and the maximum accelerations of the actuation motors in order to solve the speed jump problem caused by initial state errors, and continuous and bounded outputs were obtained. The effectiveness including the anti-interference ability of the proposed trajectory tracking controller was verified through MATLAB simulations.

关键词： Kinematics Lyapunov methods Neurodynamics Nonholonomic systems Spherical mobile robot Trajectory tracking

Micro-vibration Modeling and Verification of Shutter Mechanism of Survey Space Telescope

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Research in Astronomy and Astrophysics 2023年第1期23卷 242-253页

作者： Tong-Lei Jiang li-Hua Wen Hu zhan Bo Wang yong-Chao Yang School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China

The scientific research mission of the Survey Space Telescope(also known as the China Space Station Telescope,CSST)imposes rigorous requirements on the observation ***,microvibrations generated by the shutter mechanism can seriously affect the performance of the highly precise and sensitive instruments *** study presents a dynamic model and verifies its performance using experimental ***,a five-degreeof-freedom nonlinear dynamic model that considers all interference sources and bearing nonlinearity is *** validity of the proposed model is verified using experimental measurements of the microvibration *** obtained results proved that the proposed dynamic model can accurately predict the characteristics of the microvibrations caused by the shutter mechanism in the design stage and provide a theoretical basis for the development of CSST.

关键词： telescopes-surveys-methods numerical-methods analytical

Recursive recurrent neural network:A novel model for manipulator control with different levels of physical constraints

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CAAI Transactions on Intelligence Technology 2023年第3期8卷 622-634页

作者： zhan li Shuai li Department of Computer Science Swansea UniversitySwanseaUK College of Engineering Swansea UniversitySwanseaUK

Manipulators actuate joints to let end effectors to perform precise path tracking *** neural network which is described by dynamic models with parallel processing capability,is a powerful tool for kinematic control of *** to physical limitations and actuation saturation of manipulator joints,the involvement of joint constraints for kinematic control of manipulators is essential and ***,current existing manipulator control methods based on recurrent neural networks mainly handle with limited levels of joint angular constraints,and to the best of our knowledge,methods for kinematic control of manipulators with higher order joint constraints based on recurrent neural networks are not yet *** this study,for the first time,a novel recursive recurrent network model is proposed to solve the kinematic control issue for manipulators with different levels of physical constraints,and the proposed recursive recurrent neural network can be formulated as a new manifold system to ensure control solution within all of the joint constraints in different *** theoretical analysis shows the stability and the purposed recursive recurrent neural network and its convergence to *** results further demonstrate the effectiveness of the proposed method in end‐effector path tracking control under different levels of joint constraints based on the Kuka manipulator *** with other methods such as the pseudoinverse‐based method and conventional recurrent neural network method substantiate the superiority of the proposed method.

关键词： dynamic neural networks recursive computation robotic manipulator

中山大学科技期刊出版史略(1866—2024)

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中山大学学报（自然科学版）（中英文） 2025年第1期64卷 1-27页

作者：张冰詹拔群中山大学学报编辑部广东广州510275 中山大学期刊管理中心广东广州510275

本文力图较为完整地展现中山大学100多年的科技期刊出版历史全貌,在明晰中山大学办学源流的基础上将其前身各校的科技期刊出版情况纳入梳理,整理统计出中山大学及其前身各校在正式建校前(1866—1923年)出版科技期刊25种、建校后的民国时... 详细信息

本文力图较为完整地展现中山大学100多年的科技期刊出版历史全貌,在明晰中山大学办学源流的基础上将其前身各校的科技期刊出版情况纳入梳理,整理统计出中山大学及其前身各校在正式建校前(1866—1923年)出版科技期刊25种、建校后的民国时期(1924—1948年)出版科技期刊87种,共和国时期(1949—2024年)出版科技期刊60种,共计172种,并对代表性刊物进行简要介绍。中山大学的科技期刊出版以医学类期刊的贡献最为突出,其影响一直延续至今。这些科技期刊从科研学术角度记录了中山大学的学科发展历史,同时为中国近代科学技术的传播和发展作出了重要的贡献。

关键词：中山大学科技期刊出版史校史

Hydrogen embrittlement of a microalloyed bainitic forging steel

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Journal of Iron and Steel Research International 2019年第9期26卷 1011-1021页

作者： Wei-jun Hui zhan-hua Wang Zhi-bao Xu yong-jian zhang Xiao-li Zhao Materials Science and Engineering Research Center School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Yantai Branch of China North Industries Group Corporation No. 52 Institute Co. Ltd.Yantai 264003ShandongChina

The hydrogen embrittlement (HE) of a novel microalloyed bainitic forging steel with a strength level of 1100 MPa was evaluated using electrochemical charging and slow strain rate tensile test method with notched round bar specimens. The results show that the susceptibility to HE of the as-forged bainitic forging steel is notably higher than that of the quenched and tempered (Q&T) steel at same strength level, which is ascribed primarily to the presence of a relatively high amount of large blocky martensite/austenite (M/A) constituents of the former. It was found that low-temperature tempering treatment at 200 C could significantly alleviate the susceptibility to HE by a relative decrease of * 35% of the as-forged bainitic forging steel at no expense of strength and ductility, though its resistance to HE is still a little lower than that of the Q&T steel. Thus, it is suggested that efforts concerning refining of the large blocky M/A through optimizing chemical composition and processing route could help to further alleviate the susceptibility to HE of the tested bainitic forging steel.

关键词： Hydrogen embrittlement Bainitic forging steel Microstructure Granular bainite M/A constituent

Effects of cooling rate and Al on MnS formation in medium-carbon non-quenched and tempered steels

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International Journal of Minerals,Metallurgy and Materials 2015年第6期22卷 589-597页

作者： Meng-long li Fu-ming Wang Chang-rong li zhan-bing Yang Qing-yong Meng and Su-fen Tao State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing School of Materials Science and Engineering University of Science and Technology Beijing

The effect of Al on the morphology of MnS in medium-carbon non-quenched and tempered steel was investigated at three different cooling rates of 0.24, 0.43, and 200°C·s^-1. The formation mechanisms of three types of MnS were elucidated based on phase diagram information combined with crystal growth models. The morphology of MnS is governed by the precipitation mode and the growth conditions. A monotectic reaction and subsequent fast solidification lead to globular Type I MnS. Type II MnS inclusions with different morphological characteristics form as a result of a eutectic reaction followed by the growth in the Fe matrix. Type III MnS presents a divorced eutectic morphology. At the cooling rate of 0.24°C·s^-1, the precipitation of dispersed Type III MnS is significantly enhanced by the addition of 0.044wt% acid-soluble Al（Als）, while Type II MnS clusters prefer to form in steels with either 0.034wt% or 0.052wt% Als. At the relatively higher cooling rates of 200°C·s^-1 and 0.43°C·s^-1, the formation of Type I and Type II MnS inclusions is promoted, and the influence of Al is negligible. The results of this work are expected to be employed in practice to improve the mechanical properties of non-quenched and tempered steels.

关键词： medium carbon steels cooling rate aluminum content manganese sulfide formation mechanisms

Parameterization of ocean wave-induced mixing processes for finite water depth

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Acta Oceanologica Sinica 2009年第4期28卷 16-22页

作者： YANG yongzeng zhan Run TENG yong First Institute of Oceanography State Oceanic Administration Qingdao 266061 China Key Laboratory of Marine Science and Numerical Modeling State Oceanic Administration Qingdao 266061 China

Three dimensional wave-induced mixing plays an important role in shallow water area. A quite direct approach through the Reynolds average upon characteristic length scale is proposed to parameterize the horizontal and vertical shallow water mixing. Comparison of finite depth case with infinite depth results indicates that the difference of the wave-induced mixing strength is evident. In the shallow water condition, the infinite water depth approximation overestimates the mixing strength in the lower layers. The nonzero horizontal wave-induced mixing presents anisotropic property near the shore. The Prandtl＇s mixing length theory underestimated the wave-induced mixing in the previous studies.

关键词： Reynolds average Characteristic length scale Wave-induced mixing parameter

守正创新勇担时代使命——中山大学学报自然科学版创刊70周年(1955—2024)

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中山大学学报（自然科学版）（中英文） 2025年第1期64卷 28-39页

作者：詹拔群张冰中山大学期刊管理中心广东广州510275 中山大学学报编辑部广东广州510275

本文介绍《中山大学学报(自然科学版中英文)》的创刊与源流,分为创刊初期(1955—1966)、首批复刊(1973—1978)、改革开放后(1979—2012)和迈进新时代(2013—2023)四个时间段回顾该刊70年的办刊历程,着重介绍了在各个时期为该刊的发展壮... 详细信息

本文介绍《中山大学学报(自然科学版中英文)》的创刊与源流,分为创刊初期(1955—1966)、首批复刊(1973—1978)、改革开放后(1979—2012)和迈进新时代(2013—2023)四个时间段回顾该刊70年的办刊历程,着重介绍了在各个时期为该刊的发展壮大作出了重要贡献的中山大学学者及其发表的成果,展现中山大学与该刊在推动国家科学技术发展进步方面所作出的贡献。新时代以来,自然科学版致力于内涵式高质量发展取得了成效。该刊以建设世界一流科技期刊为目标,采取了策划组织大型专题专辑、变更期刊文种为中英文、实施稿件质量提升计划、不断完善数字化出版等重要办刊举措,大力推进国际化高水平科技期刊建设。

关键词：科技期刊中山大学学报自然科学版重要作者数字化出版

Synthesis,Structure and Characterization of a 3D Chiral Indium Carboxylate Metal-organic Framework Based on 1,1'-Biphenol ligand

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Chinese Journal of Structural Chemistry 2017年第12期36卷 2081-2086页

作者： MENG Chun-Long li Zi-Jian liU Yan liU Bai-zhan CUI yong State Key Laboratory of Metal Matrix Composites School of Chemistry and Chemical EngineeringShanghai Jiaotong UniversityShanghai 200240China China Tobacco Shanghai 200240China

A novel indium-based chiral metal organic-framework 1 {In2L（μ2-O）（H2O）3}n was synthesized from C2-symmetric 1,1？-biphenol-based ligand H4 L and structurally characterized by single-crystal and powder X-ray diffraction, Fourier-transform infrared spectra（FTIR）, solid-state circular dichroism（CD） and thermal gravimetric analysis（TGA）. 1 crystallizes in monoclinic space group P21 with a = 10.1861（5）, b = 18.5632（9）, c = 16.5153（8） A^°, V = 3077.1（3） A^°^3, Z = 2, Mr = 944.29 g/mol, Dc = 1.019 g/cm^3, F（000） = 944, GOOF = 0.932, the final R = 0.0577 and w R = 0.1091 for 22090 observed reflections with I 〉 2σ（I）. Each In2 cluster in 1 is linked by four ligands and each ligand is coordinated to four In2 clusters to generate a 3D network. Additionally, the photoluminescence of 1 and H4 L were also investigated.

关键词： 1,1?-biphenol indium chiral metal-organic framework photoluminescence