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Forward Dynamics Analysis of the 6-PUS Mechanism Based on Platform-Legs Composite Simulation

Chinese Journal of Mechanical Engineering 2009年第4期22卷 496-504页

作者： WANG Hao chen Genliang LIN Zhongqin Key Laboratory of Auto-body Engineering in Shanghai City Shanghai Jiao Tong University Shanghai 200240 China State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China

The dynamics analysis plays an important role for the control, simulation and optimization of the parallel manipulators. Normally, the Stewart type manipulators have a platform and several legs. The inverse dynamics can be solved efficiently by taking the advantage of such structural characteristics. However, for the forward dynamics analysis, this structural decomposition still faces challenges from both modeling and computation. In this paper, an efficient approach is proposed for the forward dynamics of the 6-PUS manipulator based on the platform-legs composite simulation. By composite method, the dynamics modeling of the parallel manipulator is separated into the forward dynamics of the platform and the kineto-statics of the legs. The global simulation model can be constructed by connecting the predefined platform model and leg models according to the manipulator＇s topology. Thus, the global simulation can be decomposed into the independent calculations of purely algebraic equations and ordinary differential equations （ODEs）, the computational cost can be reduced and the stability of the simulation can be improved. For the purpose of solving the manipulator＇s forward dynamics accurately, the algebraic-loop problem is discussed and a closed form algorithm is proposed. A numerical example of the 6-PUS manipulator is given to demonstrate the effectiveness of the proposed approach. The example results show that the modeling efficiency can be improved and the simulation stability can be ensured for decomposing the system equations into purely algebraic equations and ODEs.

关键词： forward dynamics Gough-Stewart platform simulation

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Thermodynamic Analysis and Optimization of an Irreversible Maisotsenko-Diesel Cycle

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Journal of Thermal Science 2019年第4期28卷 659-668页

作者： ZHU Fuli chen Lingen WANG Wenhua College of Power Engineering Naval University of EngineeringWuhan 430033China Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China School of Mechanical & Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China

So far,Maisotsenko cycle has been applied to many fields such as heating ventilation and air-conditioning,power industry,chemical production,and so on.A lot of researches about classical thermodynamic analyses of Maisotsenko cycle have been made.A new cycle model of combined Diesel and Maisotsenko cycles considering heat transfer loss(HTL),piston friction loss(PFL)and internal irreversible loss(IIL)was proposed in this *** using the finite time thermodynamic(FTT)theory,the power and efficiency performances of the Maisotsenko-Diesel cycle(MDC)were *** of mass flow rate(MFR)of water injection in the Maisotsenko air saturator(MAS)and the other parameters related to the design of Diesel engine on the optimal cycle performances were ***,it was testified that irreversible MDC was superior than conventional irreversible Diesel cycle in both power output and thermal *** results can expand the application of Maisotsenko cycle(M-cycle)and provide some theoretical guidelines for the practical devices.

关键词： Maisotsenko-Diesel cycle finite-time thermodynamics power output thermal efficiency performance optimization

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Tunable Curie temperature and magnetocaloric effect of FeCrMoCBYNi bulk metallic glass with different crystallized phases

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Journal of Rare Earths 2019年第4期37卷 404-409页

作者： Yuanbin Lv Qingjun chen Youlin Huang School of Materials Science and Engineering Nanchang Hangkong University

The investigation on Curie temperature and magnetocaloric effect of the FeCrMoCBYNi bulk metallic glass(BMG) with different crystallized phases was carried out by XRD,TEM and PPMS. The experimental results show that the Curie temperature(T_c) of Fe_(45)Cr_(15)Mo_(14)C_(15)B_6 Y_2 Ni_3 BMG with different annealing condition reaches a highest value of 95 K. The value of magnetic entropy change △S_M(T) of Sample 3 reaches a maxima of 0.48 J/(kg·K) at Tc temperature, which result from the interaction among the precipitated phases of(Fe,Cr)_(23)(C,B)_6, Fe_3 Mo_3 C and residual amorphous phase. Based on the experiment results, it can be obtained that the Curie temperature, magnetocaloric effect can reach their optimal value at low temperature, when the content of amorphous phase and precipitated phases type run up to certain value. The magnetic properties of Sample 1 with full amorphous phase and Sample 4 with full crystalline phase will both decrease.

关键词： Bulk metallic glass Crystallization Curie temperature Magnetocaloric effect Rare earths

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Crystallization of self-propelled particles on a spherical substrate

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Applied Mathematics and Mechanics(English Edition) 2019年第10期40卷 1387-1398页

作者： Yan FANG chen WANG Hongyuan JIANG CAS Key Laboratory of Mechanical Behavior and Design of Materials Hefei National Laboratory for Physical Science at the Microscale Department of Modern Mechanics University of Science and Technology of China

In this paper, we investigate the self-propelled particles confined on a spherical substrate and explore the structural and dynamic properties of self-propelled particles by controlling the packing fraction and activity. We find that these self-propelled particles freeze into the crystal with the increase in the packing fraction. We observe the pattern evolution of inevitable topological defects due to the geometric constraints of the spherical substrate. During the process of freezing, there is a transition from twelve isolated grain boundaries to the uniform distribution of defects with the increase in the self-propelled velocity. Finally, we establish a phase diagram of the freezing process. These results may deepen our understanding of active particles in complex and crowded environments.

关键词： self-prop elled particle freezing process geometric constraint defect

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A low-power high-quality CMOS image sensor using 1.5 V 4T pinned photodiode and dual-CDS column-parallel single-slope ADC

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Journal of Semiconductors 2022年第8期43卷 53-59页

作者： Wenjing Xu Jie chen Zhangqu Kuang Li Zhou Ming chen chengbin Zhang Institute of Microelectronics Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Will Semiconductor Co.Ltd. Shanghai 201210China

This paper presents a low-power high-quality CMOS image sensor(CIS)using 1.5 V 4T pinned photodiode(4T-PPD)and dual correlated double sampling(dual-CDS)column-parallel single-slope ADC.A five-finger shaped pixel layer is proposed to solve image lag caused by low-voltage ***-CDS is used to reduce random noise and the nonuniformity between ***-mode counting method is proposed to improve circuit robustness.A prototype sensor was fabricated using a 0.11μm CMOS *** results show that the lag of the five-finger shaped pixel is reduced by 80%compared with the conventional rectangular pixel,the chip power consumption is only 36 mW,the dynamic range is 67.3 dB,the random noise is only 1.55 e^(-)_(rms),and the figure-of-merit is only 1.98 e^(-)·nJ,thus realizing low-power and high-quality imaging.

关键词： CMOS image sensor 4T pinned photodiode single-slope ADC correlated double sample counting method

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STEAM教育理念下幼儿户外游戏策略

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林区教学 2025年第1期 121-124页

作者：陈兰兰周波四川轻化工大学教育与心理科学学院四川自贡643002 四川文理学院教务处四川达州635002

STEAM教育理念下的幼儿户外游戏可以促进幼儿综合能力的发展,游戏提供了实践和实验的机会,鼓励幼儿观察、探索和解决问题。同时,游戏还鼓励幼儿之间的合作与沟通,培养他们的团队合作精神和社交技能。在设计STEAM教育理念下的幼儿户外游... 详细信息

STEAM教育理念下的幼儿户外游戏可以促进幼儿综合能力的发展,游戏提供了实践和实验的机会,鼓励幼儿观察、探索和解决问题。同时,游戏还鼓励幼儿之间的合作与沟通,培养他们的团队合作精神和社交技能。在设计STEAM教育理念下的幼儿户外游戏时,面临以下问题:幼儿个体化发展欠缺,教学环节程序化,介入时机把控不到位。基于STEAM教育理念的幼儿户外游戏可采取创设问题情境、尊重个体差异、灵活变通活动安排、提高指导有效性等策略。

关键词： STEAM教育理念幼儿户外游戏

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Study on deuteron formation mechanism in nucleon-induced reactions

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Nuclear Science and Techniques 2020年第8期31卷 129-136页

作者： Ya-Jun He chen-chen Guo Jun Su Long Zhu Zhen-Dong An Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China

The mechanism of deuteron formation in neutron-induced reactions is studied within the framework of the isospin-dependent quantum molecular dynamics model,using the GEMINI *** influence of the n+p→d reaction channel is investigated by analyzing the deuteron production cross sections in the neutron-induced reactions12C(n,d),16O(n,d),and 28Si(n,d),with incident energies of 20-100 *** including the n+p→d reaction channel when modeling the collision,the deuteron production cross sections increase,optimizing the cross-section results and bringing them closer to the experimental data *** indicates that the n+p→d reaction channel is an important mechanism for enhancing deuteron production.

关键词： Cluster mechanism Deuteron formation cross section Nucleon-induced reactions

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Designing electrolytes for lithium metal batteries with rational interface stability

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Rare Metals 2021年第2期40卷 243-245页

作者： chen-Xuan Xu Jian-Jun Jiang School of Physics and Electronics Hunan UniversityChangsha410082China

Lithium(Li)-ion batteries(LIBs)have promoted the development of portable electronics and electric vehicles[1,2].However,with the rapid increase in energy demand,it is increasingly urgent to develop batteries with high energy density[3].Li metal batteries(LMBs)are considered as the"Holy Grail"which have attracted much attention due to the high theoretical capacity(3860 mAh·g^(-1))and low redox potential(-3.040 V *** standard hydrogen electrode)[4,5].

关键词： lithium rational interface

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Ligand Effects in Dinitrogen Hydrogenation of Binuclear Zirconium Complexes

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Chinese Journal of Structural Chemistry 2008年第2期27卷 238-244页

作者： LIU Cai-Ping WU Ke-chen State Key Laboratory of Structural Chemistry Fujian Institute of Research on theStructure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China

In this work, we report a theoretical exploration of the ground-state electronic structures and molecular vibrational properties of a series of binuclear zirconium complexes in the framework of density functional theory （DFT） employing the B3LYP hybrid functional. The calculated results reveal that the electronic structure of the complex [（η^5-C5Me5）2Zr]2（μ^2, η^2, η^2-N2） is unfavorable for hydrogenation due to the exclusion of side-on dinitrogen in the LUMO＋ 1 molecular orbital as compared with the reactant 1 [（η^5-C5Me4H）2Zr]2（μ2,η^2,η^2-N2）. Besides, the structural feature of the hypothetical intermediate 1′, [（η^5C5Me4H）2Zr]2（μ2,η^2, η^2-N2）-n2, clearly implies the possibility of further hydrogenation. In addition, the distinguishing of vibrational modes of experimental intermediate 2, [（η^5-C5Me4H）2ZrH]2（μ2,η^2,η^2-N2H2）, indicates that the asymmetric stretching of Zr-N and Zr-H leads to dissociation. Moreover, the vibrational intensity of Zr-H is stronger than that of Zr-N. Therefore, it can be predicted that excess hydrogen atmosphere is necessary to ensure the dissociation of Zr-N bonds.

关键词： density functional theory binuclear zirconium complexes electronic structure vibrational properties dinitrogen hydrogenation

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I-beam Crack Identification Based on Study of Local Flexibility due to Crack

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Chinese Journal of Mechanical Engineering 2011年第6期24卷 1116-1122页

作者： LI Bing chen Xuefeng HE Zhengjia State Key Laboratory for Manufacturing System Xi’an Jiaotong UniversityXi’an 710072China

Local flexibility of crack plays an important role in crack identification of *** methods on local flexibility in a cracked beam with simple geometric crossing sections,such as rectangle,circle,have been made,but there are some difficulties in calculating local flexibility in a cracked beam with complex crossing section,such as pipe and *** this paper,an analytical method to calculate the local flexibility and rotational spring stiffness due to crack in I-beam is *** local flexibility with respect to various crack depths can be calculated by dividing a cracked I-beam into a series of thin *** forward and inverse problems in crack detection of I-beam are *** forward problem comprises the construction of crack model exclusively for crack section and the construction of a numerically I-beam model to gain crack detection *** inverse problem consists of the measurement of modal parameters and the detection of crack *** experiments including measurement of rotational spring stiffness and prediction of cracks in I-beam are *** results based on the current methods indicate that relative error of crack location is less than 3%,while the error of crack depth identification is less than 6%.Crack identification of I-beam is expected to contribute to the development of automated crack detection techniques for railway lines and building skeletons.

关键词： crack identification I-beam local flexibility

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