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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,peking 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

Analysis of the observation of particle detector inside ‘CBERS-1’ satellite under solar quiet conditions

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Science china(Technological Sciences) 2006年第3期49卷 342-357页

作者： ZOU Hong1, XIAO Zuo1, HAO Yongqiang1, ZOU Jiqing1, ZHU Wenming2, WU Zhongxiang2 & XIANG Hongwen2 1. department of geophysics, peking university, beijing 100871, china 2. Chinese Academy of Space Technology, beijing 100086, china department of geophysics Peking University Beijing 100871 China Chinese Academy of Space Technology Beijing 100086 China

Based on the knowledge and related theory of earth’s radiation belt, the data of energetic particles observed by detectors onboard ‘CBERS-1’ satellite at a solar syn- chronous orbit were analyzed. It is proved that the observational results are in agreement with the theoretical description of the radiation belt structures. Analysis of more than 3 years’ data showed clearly that under quiet solar conditions, at a height of about 800 km the energetic particles were mainly located in three regions: northern auroral belt (40°― 80°), southern auroral belt (?40°― ?80°) and South Atlantic Geomagnetic Anomaly Re- gion (SAA). Actually, this is for the global distribution, at each longitude the latitudinal coverage is much narrower and particles are along the geomagnetic latitude of about ±60°. The species of particles in different regions and their counting rates are different. In SAA, usually both electrons and protons are observed, which should come from inner radiation belt; in polar regions only energetic electrons are observed under the quiet condition, which belongs to the outer radiation belt. The distribution of outer radiation electrons is asymmetrical for longitudes as well as northern and southern polar regions. These asymmetries can be explained with the reflecting altitudes of the mirror points of charged particles at the same L shell.

关键词： radiation-belts, energetic-particle, drift-shell, mirror-point.

Two applications of generalized Carleson measures to meromorphic Besov-type spaces

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Chinese Science Bulletin 1998年第15期43卷 1260-1264页

作者： TAN Haiou 1 and XIAO Jie 2 1. department of Mathematics, Wuyi university, Jiangmen 529020, china 2. School of Mathematical Sciences, peking university, beijing 100871, china department of Mathematics Wuyi University Jiangmen China School of Mathematical Sciences Peking University Beijing China

The generalized Carleson measures are used to characterize the meromorphic Besov_type spaces and to explore some inclusions between these spaces.

关键词： generalized Carleson measures meromorphic Besov_type spaces.

The refined theory of deep rectangular beams based on general solutions of elasticity

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Science china(Physics,Mechanics & Astronomy) 2006年第3期49卷 291-303页

作者： GAO Yang1 & WANG Minzhong2 1. College of Science, china Agricultural university, beijing 100083, china 2. State Key Laboratory for Turbulence and Complex Systems and department of Mechanics and Engi- neering Science, peking university, beijing 100871, china College of Science China Agricultural University Beijing 100083 China State Key Laboratory for Turbulence Complex Systems department of Mechanics Engineering Science Peking University Beijing 100871 China

The problem of deducing one-dimensional theory from two-dimensional the- ory for a homogeneous isotropic beam is investigated. Based on elasticity theory, the re- fined theory of rectangular beams is derived by using Papkovich-Neuber solution and Lur’e method without ad hoc assumptions. It is shown that the displacements and stresses of the beam can be represented by the angle of rotation and the deflection of the neutral surface. Based on the refined beam theory, the exact equations for the beam without transverse surface loadings are derived and consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beam under transverse loadings are derived directly from the refined beam theory and are almost the same as the governing equations of Timoshenko beam theory. In two ex- amples, it is shown that the new theory provides better results than Levinson’s beam the- ory when compared with those obtained from the linear theory of elasticity.

关键词： deep rectangular beams,the refined theory,Papkovich-Neuber solution,Lur'e method,governing equation

New direction of computational fluid dynamics and its applications in industry

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Science china(Technological Sciences) 2007年第5期50卷 521-533页

作者： CHEN YaoSong1, SHAN XiaoWen2 & CHEN HuDong2 1 department of Mechanics, peking university, beijing 100871, china 2 Exa Corporation, Burlington, MA 01803 USA 1. department of Mechanics Peking University Beijing 100871 China 2. Exa Corporation Burlington MA 01803 USA

For the past ten years there has been much progress in computational fluid dy- namics (CFD), among which the formation and development of the lattice Boltz- mann method (LBM) are an important new direction. We give a review on the main aspect and the latest development of this method in this article, and at the same time we also discuss the related development of scientific software and its impact on the real-world applications in industry.

关键词： lattice method, Boltzmann equation, CFD

Constructions of Some Exact VortexSuperposition Solutions

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Communications in Nonlinear Science and Numerical Simulation 1999年第4期4卷 3-5页

作者： Xin HU Yonghan HUANG(department of Mechanics and Engineering Science, State Key Laboratory for TurbulenceResearch, peking university, beijing 100871, china) department of Mechanics and Engineering Science State Key Laboratory for Turbulence Research Peking University Beijing 100871 China

IntroductionOneofthemostusefulmethodstosolvetheN-Sequationistodecomposethevelocity（l）(z)where.（'）--acNow,***3=w3（t）,wewillthengetco3=coear(jb（t）dt).Ifwetakeg=--M（axl+fixs）+ac,T=--M（Axf+Bx;）+cohere,goandcos... 详细信息

关键词： exact solution Stokes-Helmholtz decomposition vorticity equation

A Systematic Study on Scaling Law of Spiral Waves

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Communications in Nonlinear Science and Numerical Simulation 1999年第3期4卷 3-5页

作者： Shufeng BAI,Yan LI and Qi QUYANG(These auhors attribute equally to this article)(department of Physics,peking university,beijing 100871,china) department of Physics Peking University Beijing 100871 China

Pactedsformationfarfromthermodynamicsequilibriumareubiquitousintheworld,typicalofwhichisthespiralpattern,***-diffusionsystems,***,whOSetiporbitsaci... 详细信息

Pactedsformationfarfromthermodynamicsequilibriumareubiquitousintheworld,typicalofwhichisthespiralpattern,***-diffusionsystems,***,whOSetiporbitsaci...

关键词： spirals non-linear waves scaling law

Preliminary experiments from a nonsteady atmosphere-earth surface coupled anomaly model

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Acta Oceanologica Sinica 1988年第3期7卷 369-380页

作者： Lin Benda, Xu Xiaodong and Wang Shaowu department of geophysics, peking university, beijing, china Dept. of geophysics Peking Univ. Beijing China China

In this paper, a nonsteady atmosphere-earth surface coupled anomaly model is used to conduct both comparative experiments on the physical processes of model and monthly forecasting experiments for anomaly fields. It is shown that after further improvement it is hopeful for the anomaly model with two-hour time step to do monthly forecasting of anomaly fields by taking long period time integration. The comparative experiments show that the interaction between the atmosphere and the surface has significant influence on the long range variation for both atmospheric geopotential anomalies and surface temperature anomalies, and transient eddy transport has also certain effects on the variation of anomaly fields.

关键词： Preliminary experiments from a nonsteady atmosphere-earth surface coupled anomaly model

Some Results on the Multiplier Conjecture for the Case n=5n_1

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Acta Mathematica Sinica,English Series 1998年第4期14卷 535-540页

作者： Wan Zhaoze, department of Mathematics, peking university, beijing 100871, china peking university Department of Mathematics Beijing China (GRID:grid.11135.37) (ISNI:***)

Using the method presented in [1], we obtain some new results which improve on the result of MacFarland’s theorem (see [2]) in this case.

关键词： Difference sets Multiplier CH-equations