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Science china(Information Sciences) 2011年第3期54卷 469-481页

作者： WANG Nan 1,2. ZHANG TianWu 2.& XU JieQiong 1 1 school of Aeronautic Science and engineering,{2., {3. 100191, china 2.Department of Computer Science and engineering, Henan Institute of engineering, Zhengzhou 451191, china 1. school of Aeronautic Science and engineering Beijing University of Aeronautics and Astronautics Beijing 100191 China2. Department of Computer Science and Engineering Henan Institute of Engineering Zhengzhou 451191 China

In this paper, several formation controllers are developed with constant and variable connected communication topology for six-degree-of-freedom (6-DOF) networked spacecraft flying in deep space with constant and time-varying communication delays considered. In the control algorithm, any explicit leader does not exist in the formation team and it is required that each spacecraft communicate only with its neighbors and therefore the required communication loads of the whole formation is greatly reduced. The proposed control strategies allow that each spacecraft can track its desired position and attitude and simultaneously the whole group moves to the desired formation and obtain its desired relative attitudes with its neighbors. Simulation results demonstrate the effectiveness of the proposed controllers.

关键词： deep space graph theory formation control communication topology delays

Special Orientation Relationships Observed at the Early Stages of Recrystallization in Pure AlMn Alloy

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International Journal of Minerals,Metallurgy and materials 1998年第3期12卷 140-146页

作者： Ping Yang(material Science and engineering {2., {3. of Science and Technology beijing, beijing 100083. china)(Institute for Metal Science and Metal Physics, Aachen {3. of Technology, D-52.56, Aachen, Germany) material Science and engineering {2. University of Science and Technology Beijing Beijing 100083 China Institute for Metal Science and Metal Physics Aachen University of Technology D-52056 Aachen Germany

Electron Back Scattering Diffraction (EBSD) technique in a SEM was used to obtain local orientationalinformation on new grains and their surrounding deformed matrices at the early stages of recrystallization in pureA1-1 .3.Mn alloy. Results show that special orientation relationships including twin-relationship often exist betweennew grains, between new grains and deformed grains or between deformed grains. The occurrence of such specialorientation relationships is attributed to the special deformation behavior in the samples with large initial grain *** formation of recrystallization twins is discussed in a different way to those of traditional ones.

关键词： Orientation relationship recrystallization AlMn, EBSD

Temperature Field and Microstructural Formation of Semi-Solid AlSi_7Mg Alloy

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International Journal of Minerals,Metallurgy and materials 2000年第2期14卷 99-102页

作者： Weimin Mao Aimin Zhao Yan jun Li Chenglin Cui Feng Sun Xuryou Zhong(material Science and engineering {2., {3. of Science and Technology beijing, beijing 100083. china) material Science and engineering {2. University of Science and Technology Beijing Beijing 100083 China

The microstructural formation of the semi-solid AlSi7Mg alloy stirred by electromagnetic field is investigated together withthe tempeatre field of the stirred melt at continuously cooling. A impoat kinetic factor for primny a-Al nucleation is proposed. It isfound that a low temperatUre gradient exists in the electromagnetic stirred melt. This is why the first dendritic arms and secondary de-ndritic arms are refmed. Experimefltal results also show that the root remelting of secontw dendritic arms is an twortat mechanismfor the primary α-Al refmement. Strong electromagnetic stirring greatly reduces the composition supercooling in the melt and eliminatesprefedrig growth of the first dendritic arms. Therefore, many rosettes or spherical Primary α-Al phase particles form finally.

关键词： AlSi_7Mg alloy semi-solid electromagnetic stirring

ANALYSIS OF SPATIAL COMPLIANCE BEHAVIOR OF COILED SPRINGS VIA SCREW THEORY

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Chinese Journal of Mechanical engineering 2002年第4期15卷 293-297,318页

作者： Ding XilunRobotics Research Institute, beijing university of aeronautics and astronautics,beijing {2. {3.Selig J M South Bank university, UK Robotics Research Institute Beijing University of Aeronautics and Astronautics 北京 100083 South Bank university 英国

A new method is presented to describe and analyze the spatial compliance ofcoiled springs using screw theory. After an abbreviated description for the deformation of a beamelement using screw theory, the spatial compliance density for a beam element is derived based onthe fundamental material theory and reasonable assumptions, and the spatial compliance of the beamwith finite length is obtained by integral. The spatial compliance of coiled springs is furtheranalyzed using the spatial compliance density of the beam element. By calculating theeigencompliance and Ball's principle screws for the whole compliance of system, the complianceproperties varying with the basic physical parameters of the system are illustrated in detail. Thebasic ideas can be used for the design and application of the coiled springs and the other compliantmechanisms with spatial compliant beam element.

关键词： eigencompliance coiled springs screw theory mechanisms

Modified HDDR Process for Producing Anisotropic NdFeB Powders

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Journal of university of Science and Technology beijing 2001年第2期8卷 111-114页

作者： Xubo Liu, Yue Ming, Yaofu Xiao, Qi Zeng, Zhengyi Zhang, Run Wang (material Science and engineering {2., {3. of Science and Technology beijing, beijing 100083. china) (beijing Institute of Aeronautical materials, beijing 100095, china) Univ Sci & Technol beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China Inst Aeronaut Mat Beijing 100095 Peoples R China

The effect of HDDR (hydrogenation-decomposition-desorption-recombination process) treating conditions on magnetic anisotropy of Nd13.ebalCo17B7Ga1Zr0.1 powders has been studied. It is found that increasing recombination temperature is effective for magnetic anisotropy formation, but at the cost of reducing the coercive force. The microstructure analysis (TEM) indicates that the NdFeB recombination nucleation takes place markedly during the transition range from decomposition stage to recombination stage, in which both temperature and H-2.pressure change sharply. In order to create a more stable treatment condition for recombination nucleation, a modified HDDR process is established in which the conventional continuous transition range is divided into several stages. The experimental results have proved that such a process can effectively enhance the remanence of the magnet powders with high certainty, while only cause a little reduction in coercivity.

关键词： HDDR anisotropy NdFeB

Single rub-impacting periodic motions of a rigid constrained rotor system

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Communications in Nonlinear Science and Numerical Simulation 2000年第4期5卷 158-161页

作者： Qunhong LI and Qishao LU (school of Science, beijing university of aeronautics and astronautics, {2. 100082. {3.) (Received September 2., 2.00) school of Science Beijing University of Aeronautics and Astronautics Beijing 100083 China

This paper discusses the existence of single rub-impacting period-n motions for a kind of rotor systems with rigid constraints. The ranges of parameters for period-2.motions are also given. An example of this method i... 详细信息

关键词： rotor system rod constraint rub-impacting mapping periodic motion\

Effect of Al^(3.) on Tobermorite Crystallinity

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International Journal of Minerals,Metallurgy and materials 2000年第2期14卷 79-81页

作者： Fengmei Liu Deping Chen Wen Ni Zhenyuan Cao(Resource engineering school, {2. of Science and Technology {3., beijing 100083. china) Univ Sci & Technol beijing Resource Engn Sch Beijing 100083 Peoples R China

The difference between the systems of CaO-SiO2.-H2. and CaO-SiO2.Al(OH)3.-H2., was studied, especially the effect of Al3.on the crystallinity of tobermorite was focussed. As a result, in the system of CaO-SiO2.H2., tobermorite formed early, however, withreaction time forward, tobermorite was replaced by xonotlite. So far as CaO-SiO2.Al(OH)3.-H2. was concemed, hydrothermal reactionwas cdried out under the same condition as CaO-SiO2.H2. to study the morphological changes of tobermorite crystals. It was found thatAl3. accelefated the crystal growth of tobermorite to some extent and was in faVor ofplaty crystals. Moreovef, with the Al3. content in-creasing in the starting material, the morphology of tobermorite did not change magnificently, but platy crystals became more and moreeminent. As soon as the Al2.3.content was over 15.6%, synthetic mineral greatly changed in smicthe and haled into hibschite differentfrom 1 .1 nm tobermorite. Obviously, xonotlite was not apt to form in the presence of Al3..

关键词： calcium silicate hydrate xonotlite 1.1 nm tobermorite hibschite

Fretting corrosion of surgical 3.6L stainless steel in saline solutions

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International Journal of Minerals,Metallurgy and materials 1997年第3期11卷 18-21页

作者： BAI Zhijun WU Yinshun ZHANG Tiancheng LIU Qiang (material Science and engineering {2., {3. of Science and Technology beijing, beijing 100083. china)

A new simulation system for the laboratory investigation of fretting wear is developed. It consist of a mechanism device, a electrochemical cell and a datum acqulsition and process software. Fretting of surgical 3.6L stainlesssteel in saline is studied. The results show that electrochemical corrosion is enhanced by fretting and anodic currentdensity under fretting is 100 times than static condition. Fretting corrosion is a mechanic -elec trochemical al Process.

关键词： fretting system 3.6L sninless steel saline solution

A construction of hyperbent functions with polynomial trace form

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Science china Mathematics 2011年第10期54卷 2229-2234页

作者： CAO XiWang1,2.3.& HU Lei3.1Department of Mathematics,Nanjing {2. of aeronautics and astronautics,Nanjing 2.0016,{3. 2.MIB of Ministry of Education,beijing {2. of aeronautics and astronautics,beijing 100191,{3. 3.tate Key Laboratory of Information Security,Graduate school of Chinese Academy of Sciences,beijing 100049,{3. 1. Department of Mathematics Nanjing University of Aeronautics and Astronautics Nanjing 210016 China2. LMIB of Ministry of Education Beijing University of Aeronautics and Astronautics Beijing 100191 China3. State Key Laboratory of Information Security Graduate School of Chinese Academy of Sciences Beijing 100049 China

This paper presents a construction of infinite classes of binary and p-ary hyperbent functions of polynomial trace form,based on finding a zero of a Kloosterman sum.

关键词： bent function hyperbent function Kloosterman sums

Physical analysis and numerical simulation for the dynamic behaviour of vehicles in pitching oscillations or rocking motions

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Science china(Technological Sciences) 2007年第4期50卷 385-401页

作者： ZHANG HanXin1,2.3. ZHANG Zhao1,3. YUAN XianXu1,2. LIU Wei1, XIE YuFei1,2.& YE YouDa1,2.1 {2. Aerodynamics Research and Development Center, Mianyang 62.000, {2. 2.National Laboratory for Computational Fluid Dynamics, beijing university of aeronautics and astronautics,{3. 3.school of Aerospace, Tsinghua university, beijing 100084, {2. 1. china Aerodynamics Research and Development Center Mianyan 621000 China 2. National Laboratory for Computational Fluid Dynamics Beijing University of Aeronautics and Astronautics Beijing 100083 China 3. school of Aerospace Tsinghua University Beijing 100084 China

Analytical methods of nonlinear dynamics and numerical simulations for the cou-pling equations of Navier-Stokes and flight mechanics are used to study the dynamic behaviour of pitching motions of reentry capsules with the variation of Mach number, and rocking motions of swept wings with the variation of angle of attack. Conditions under which the dynamic instability, Hopf bifurcation and saddle-node bifurcation occur are obtained. The node-saddle-node topological structure in the phase portrait, i.e. the state of bi-attractors (attracting basins) is described. The evolving process of dynamic behaviour and flow fields are given. The theories are compared with some numerical simulations conducted by the authors. Besides, some verifiable experi-mental results are cited. The agreement between them is very well.

关键词： physical analysis numerical simulation pitching oscillation rocking motion bifurcation