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SYNTHESIS OF PERFLUORO-1-OCTANESULFONATED FULLERENE AND THE FRICTION PROPERTIES OF ITS THIN FILM

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Chinese Journal of polymer science 2002年第5期20卷 397-400页

作者： Lan Huang Shuang Fan Fang Wei Xin-sheng Zhao Jin-xin Xiao Bu-yao Zhu college of chemistry and Molecular engineering peking university{3., China peking Univ Coll Chem & Mol Engn Beijing 100871 Peoples R China

A star-shaped compound of perfluoro-1-octanesulfonated fullerene was synthesized. The measurement of the friction for its spin-coating film by friction force microscopy (FFM) reveals that the films possess lower frict... 详细信息

关键词： perfluoro-1-octanesulfonated fullerene thin film friction force microscopy (FFM)

TWO KINDS OF HARMONIC PROBLEMS IN CONTROL SYSTEMS

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Journal of Systems science & Complexity 2009年第4期22卷 587-596页

作者： Zhisheng DUAN Lin HUANG State Key Lab for Turbulence and Complex Systems and department of Mechanics and Aerospace engineering,college of engineering,peking university,beijing 100871,China. State Key Lab for Turbulence and Complex Systems and department of Mechanics and Aerospace engineering College of Engineering Peking University Beijing 100871 China

This paper discusses the harmonic problems in control systems from two aspects:Oneis the harmonic control among different subsystems,and the other is the harmonic control amongmultiple *** intrinsic problems in such systems are *** is pointed out that somesubsystems must be unstable to stabilize the whole interconnected system by an *** discrete-time multi-input systems,a necessary and sufficient condition is presented for the strictdecrease of the quadratic optimal performance index with the control input *** showsan essential difference between single-input and multi-input control ***,some futureresearch directions are discussed in harmonic control of interconnected systems,allocation of multi-control inputs,fault-tolerant control,and fault-diagnosis.

关键词： Interconnected system quadratic optimal control redundant inputs Riccati equation simplectic matrix.

The refined theory of deep rectangular beams for symmetrical deformation

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science China(Physics,Mechanics & Astronomy) 2009年第6期52卷 919-925页

作者： GAO Yang1 & WANG MinZhong2 1 college of science, China Agricultural university, {3. 100083. China 2 State Key Laboratory for Turbulence and Complex Systems and department of Mechanics and Aerospace engineering, peking university, beijing 100871, China college of science China Agricultural University Beijing 100083 China State Key Laboratory for Turbulence and Complex Systems and department of Mechanics and Aerospace engineering Peking University Beijing 100871 China

Based on elasticity theory, various one-dimensional equations for symmetrical deformation have been deduced systematically and directly from the two-dimensional theory of deep rectangular beams by using the Papkovich-Neuber solution and the Lur'e method without ad hoc assumptions, and they construct the refined theory of beams for symmetrical deformation. It is shown that the displacements and stresses of the beam can be represented by the transverse normal strain and displacement of the mid-plane. In the case of homogeneous boundary conditions, the exact solutions for the beam are derived, and the exact equations consist of two governing differential equations: the second-order equation and the transcendental equation. In the case of non-homogeneous boundary conditions, the approximate governing differential equations and solutions for the beam under normal loadings only and shear loadings only are derived directly from the refined beam theory, respectively, and the correctness of the stress assumptions in classic extension or compression problems is revised. Meanwhile, as an example, explicit expressions of analytical solutions are obtained for beams subjected to an exponentially distributed load along the length of beams.

关键词： deep rectangular beams the refined theory symmetrical deformation the Papkovich-Neuber solution the Lur’e method

Study on the two and three-parameter working stability regions of 3.-TZP suspension

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science China(Technological sciences) 2006年第5期49卷 547-568页

作者： CHEN Youqiang1, 2, ZHANG Xinni3. CHEN Sha’ou3.& qi Ping3.1. department of {3., qingdao university, qingdao 266071, China 2. department of {3., Tsinghua university, beijing 100084, China 3. department of Physics, qingdao university, qingdao 266071, China 1. department of chemistry Qingdao University Qingdao 266071 China 2. department of chemistry Tsinghua University Beijing 100084 China 3. department of Physics Qingdao University Qingdao 266071 China

We determined the variation tendency of viscosity (η) at various solids load- ing (α) for 3.-TZP suspension as a function of dispersant concentration (Cw) using vis- cosity measurement, measured the diameter of particles as a function of Cw in very dilute suspension using light scattering method, and obtained the surface features of the sedi- ment of suspension with different Cw using SEM. We also discussed the influence of the microstructure of adsorbed polymer layers on particles and their interactions in the dis- persing medium on the stability of suspension. Then two different stable states and two different unstable states for 3.-TZP suspension were given. Accordingly, the (Cw, η), (Cw, α), and (α, η) two-parameter, and (Cw, α, η) three-parameter stability maps were con- structed. Based on the DLVO theory calculations, the dispersant concentration, particle distance (r), and interparticle potential energy (VT) maps with various solids loading for 3.-TZP aqueous suspension were also constructed. In (Cw, r) two-parameter coordinate system, the stable motion region map for particles was established. The Cw, α, and VT,max (the highest potential energy) surface of the potential barrier map was obtained through calculation and simulation on the basis of the surfaces of Cw, r, VT maps introduced above. The (Cw, α) two-parameter stability map was then obtained from the Cw, α, VT,max map. The results showed that this theoretical map can qualitatively prove the experimentally obtained results—the existence of different dispersed states of particles in suspension system and the variation tendency of suspension stability with changing each parame- ter—were reasonable.

关键词： 3.-TZP, suspension, stability, DLVO theory, interparticle potential energy.

Fabrication of multi-sectional TiO_2 nanotube arrays by anodization

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science China chemistry 2010年第5期53卷 1067-1072页

作者： LI Shiqi,YIN JianBo & ZHANG GengMin Key Laboratory for the Physics and chemistry of Nanodevices and department of Electronics,{3. university,beijing 100871,China 1. Key Laboratory for the Physics and chemistry of Nanodevices and department of Electronics Peking University Beijing 100871 China

We report a facile method to grow multi-sectional TiO2 nanotube arrays consisting of alternating bamboo-shaped and smooth-walled nanotube sections by *** key factors are necessary for obtaining these ***,in order to avoid possible disruptions between the conjoint sections of the nanotube,the distribution of hydrogen ions is suggested not to be fiercely disturbed when switching from the first to the second ***,to avoid the disruption of the nanotube at the joint which results from the disparity in diameters between sections,the direct current voltage is set to be the maximum of the square wave *** newly developed TiO2 nanotube arrays are expected to have potential applications in solar cells,drug release and delivery systems.

关键词： titanium dioxide titania nanotube anodic oxidation

COMPUTER OPTIMIZATION OF DENSITY AND VISCOSITY FOR BINARY METALLIC MELTS

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中国有色金属学会会刊：英文版 1995年第2期5卷 30-33页

作者： Zhang,Jiayun Zhou, Tuping feng, Xueliang (department of Physical chemistry,{3. of science and Technology beijing, beijing 100083. Univ of science and Technology Beijing Beijing China

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ＣＯＭＰＵＴＥＲＯＰＴＩＭＩＺＡＴＩＯＮＯＦＤＥＮＳＩＴＹＡＮＤＶＩＳＣＯＳＩＴＹＦＯＲＢＩＮＡＲＹＭＥＴＡＬＬＩＣＭＥＬＴＳ￥Ｚｈａｎｇ，Ｊｉａｙｕｎ；Ｚｈｏｕ，Ｔｕｐｉｎｇ；Ｆｅｎｇ，Ｘｕｅｌｉａｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃａｌＣｈ...

关键词： metallic melts viscosity computer optimization

Asymptotic theory for the MLE from randomly censored exponential samples

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Chinese science Bulletin 1998年第13期43卷 1071-1076页

作者： WANG qihua department of Probability and Statistics, peking university,{3., China department of Probability and Statistics Peking University Beijing China

The MLE of the parameter of the exponential population from the censored observations is considered. The Edgeworth expansions for the Studentized MLE are established by representing the relevant statistic as a U\|statistic plus a remainder. A semiparametric bootstrap method is introduced to the random censored model and the accuracy of bootstrap approximation of the MLE is investigated. Furthermore, it is shown that the MLE is asymptotically minimax efficient.

关键词： maximum likelihood estimate Edgeworth expansion bootstrap approximation asymptotic minimax efficiency law of iterated logarithm.

SYNTHESIS AND CHARACTERIZATION OF POLYSILOXANE CONTAINING OLIGO(OXYETHYLENE)SULFATE SALT

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Chinese Journal of polymer science 2000年第2期18卷 109-113页

作者： Shu-wen Hu Zheng-cheng Zhang FanYi Shi-bi Fang Xin-feng Zhang Fu-mian Li department of chemistry,{3., beijing 100871, China Chinese Acad Sci Inst Chem Beijing 100080 Peoples R China peking Univ Dept Chem Beijing 100871 Peoples R China

Solvent-free polymeric alkali-metal ion conductors, consisting of a comb-like polysiloxane with oligo(oxyethylene) side chains and pendant sulfate groups were synthesized by the hydrosilylation of allyl oligo(oxyethylene) sulfate salt and allyl methoxy oligo(oxyethylene) with poly(methylhydrosiloxane). The factors influncing the ionic conductivity of the resulting polymer such as the electrolyte content and the nature of the alkali-metal were investigated. The temperature dependence of conductivity was determined, and the ionic conductivity of the polymer follows the Vogel-Tammann-Fulcher (VTF) equation.

关键词： hydrosilylation electrolytes ionic conductivity

A stochastic method for convective storm identification,tracking and nowcasting

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Progress in Natural science:Materials International 2008年第12期18卷 1557-1563页

作者： Lei Han~(a,b) Shengxue Fu~a Guang Yang~c Hongqing Wang~b Yongguang Zheng~d Yingjing Lin~b a college of Information science and {3..Ocean university of China,qingdao 266101,China b department of Atmospheric science,peking university,beijing 100871,China c department of Probability and Statistics,peking university,beijing 100871,China d National Meteorological Center,beijing 100081,China [a]college of Information science and engineering Ocean University of China Qingdao 266101 China [b]department of Atmospheric science Peking University Beijing 100871 China [c]department of Probability and Statistics Peking University Beijing 100871 China [d]National Meteorological Center Beijing 100081 China

The convective storm identification,tracking and nowcasting method is one of the important nowcasting methodologies against severe convective *** severe convective cases,such as storm shape or rapid velocity changes,existing methods are apt to provide unsatisfied storm identification,tracking and nowcasting *** overcome these difficulties,this paper proposes a novel approach to identify,track and short-term forecast (nowcast) of convective storms.A mathematical morphology-based storm identification method is adopted which can identify storm cells accurately in a cluster of *** for the difficult tracking problem,sequential Monte Carlo (SMC) method is utilized to simplify the tracking *** is not only inherently suitable for handling complicated splits and mergers, but also capable of handling the case of storm-missing *** order to provide more accurate forecast of a storm position,this method takes the advantages of the cross-correlation *** qualitative and quantitative evaluations show the efficiency and robustness of the proposed approach.

关键词： Convective storm Doppler radar Nowcasting