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A geometrical and physical nonlinear finite element model for spatial thin-walled beams with arbitrary section

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Science china(Technological Sciences) 2010年第3期53卷 829-838页

作者： YANG QingShan 1 &WANG XiaoFeng 2 1 School of Civil Engineering,beijing jiaotong university,beijing 100044,china 2 College of Civil Engineering,Tongji university,Shanghai 200092,china School of Civil Engineering Beijing Jiaotong University Beijing China College of Civil Engineering Tongji University Shanghai China

Based on the theories of Bernoulli-Euler beams and Vlasov's thin-walled members,a new geometrical and physical nonlinear beam element model is developed by applying an interior node in the element and independent interpolations on bending angles and warp,in which factors such as traverse shear deformation,torsional shear deformation and their coupling,coupling of flexure and torsion,and second shear stress are all ***,geometrical nonlinear strain in total Lagarange(TL) and the corresponding stiffness matrix are *** plastic model is applied to physical nonlinearity to comply with the yield rule of Von Mises and incremental relationship of *** stiffness matrix is derived by numerical integration on the basis of the finite segment *** show that the developed model is feasible in analysis of thin-walled structures with high accuracy.

关键词： Spatial beams thin-walled structures geometrical and physical nonlinearity finite element arbitrary section

Lp（ [0, 1]）-characterizations of multi-knot piecewise linear spectral sequences

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Progress in Natural Science:Materials International 2006年第7期16卷 684-690页

作者： LIAN Qiaofang, CHENG Linfeng, and YAN Dunyan ( department of mathematics, beijing jiaotong university, beijing 100044, china department of mathematics, china university of Mining and Technology, Xuzhou 221008, china School of Information Science and Engineering, Graduate university of Chinese Academy of Sciences, beijing 100080, china) Chinese Acad Sci Sch Informat Sci & Engn Beijing 100080 Peoples R China china Univ Min & Technol Xuzhou 221008 Peoples R China beijing jiaotong Univ Dept Math Beijing 100044 Peoples R China

There exists a class of new orthonormal basis for L2([0, 1]), whose exponential parts are multi-knot piecewisf linear functions called spectral sequences. In this paper, we show that these bases constitute bases, but not unconditional bases, for Lp([0, 1 ]) with 1更多还原AbstractFilter('ChDivSummary', 'ChDivSummaryMore', 'ChDivSummaryReset');

关键词： exponential bases multi-knot piecewise linear spectral sequences unconditional bases.

SERIES REPRESENTATION OF DAUBECHIES' WAVELETS

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Journal of Computational mathematics 1997年第1期15卷 81-96页

作者： X.G. Lu (department of Applied mathematics, Tsinghua university, beijing, china) 清华大学应用数学系北京

This paper gives a kind of series represeotation of the scaling functions φNand the associated wavelets . constructed by Daubechies. Based on Poission sununation formula, the functions gh. φN(x+N-1), φN (x+N),'''' φN (x+2N-2)(Ox 1) are linearly represented by φN(x), φN(x + 1),''', φN(x + 2N - 2) and some polynomials of order less than N, and φ0(x):= (φN (x), φN (x + 1),''', φN (x + N -2))t is translated into a solution of a nonhomogeneous vectorvalued functional equationwhere A0, A1 are (N - 1) x (N - 1)-dimensional matrices, the components of P0(x), P1 (x) are polynomials of order less than N. By iteration, .φ0(x) is eventualy represented as an (N - 1)-dimensional vector series with vector norm where and

关键词： Pro ER Math Si WAVELETS SERIES REPRESENTATION OF DAUBECHIES

THERMAL SHOCK OF SEMI-INFINITE BODY WITH MULTI-PULSED INTENSE LASER RADIATION

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Acta Mechanica Solida Sinica 2010年第2期23卷 175-180页

作者： Haiming Huang 1 Fang Su Yue Sun(Institute of Engineering Mechanics,beijing jiaotong university,beijing 100044,china) Institute of Engineering Mechanics Beijing Jiaotong University Beijing China

In order to investigate the thermal shock and the heat conduction property of a target under multi-pulsed laser radiation, analytic expressions of both temperature and thermal stress fields in the target are deduced on the basis of the non-Fourier conduction law and the thermo-elastic theory. Taking a stainless steel target as an example, we can solve the analytic expressions under appropriate boundary conditions by using the finite difference method and MATLAB software, and then reveal the evolution law of both surplus temperaturt, and thermal stress in the target. The results indicate that the temperature curves in the target irradiated by a multi-pulsed laser take on a delayed character in different sections away from the boundary, which is only affected by its relaxation time. The front of the stress wave is very steep in the non-Fourier numerical solutions, which presents an obvious thermal shock, so it is necessary to consider the non-Fourier effect of semi-infinite body under the high energy laser radiation.

关键词： multi-pulsed laser non-Fourier effect thermal shock

ON THE RANGE OF RANDOM WALKS IN RANDOM ENVIRONMENT　

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Chinese Annals of mathematics,Series B 1995年第1期16卷 131-138页

作者： ZHOU XIANYIN(department of mathematics, beijing Normal university, beijing 100875, china.) 北京师范大学北京 100875

The range of random walk on Z￣d in symmetric random environment is investigated. As results, it is proved that the strong law of large numbers for the range of random walk on Zdin some random environments holds if d... 详细信息

关键词： Law of large numbers Ergodic theorem Range of random walk Random environment Effective resistance.

CONVERGENCE PROPERTIES OF A MODIFIED BFGSALGORITHM FOR MINIMIZATION WITHARMIJO-GOLDSTEIN STEPLENGTHS

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Journal of Computational mathematics 1999年第6期17卷 645-652页

作者： Nai-yang Deng Zheng-feng Li(department of mathematics, beijing Agricultural Engineering university, beijing 100083,china) 北京农业工程大学数学系北京 100083 北京农业工程大学数学系北京

The line search strategy is crucial for an efficient unconstrained optimization algorithm. One of the reason why the Wolfe line searches is recommended lies in that it ensures positive definiteness of BFGS updates. When gradient information has to be obtained costly, the Armijo-Goldstein line searches may be preferred. To maintain positive difiniteness of BFGS updates based on the Armijo-Goldstein line searches, a slightly modified form of BFGS update is proposed by I.D. Coope and C.J. Price (Journal of Computational mathematics, 13 (1995), 156-160), while its convergence properties is open up to now. This paper shows that the modified BFGS algorithm is globally and superlinearly convergent based on the Armijo-Goldstein line searches.

关键词： BFGS methods convergence superlinear convergence

Characteristic Surface Oxide Film Cracking Behavior of a Fe-Ni-Cr Alloy under In-phase and Out-of-phase Thermo-mechanical Fatigue

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Journal of Wuhan university of Technology(Materials Science) 2008年第6期23卷 850-853页

作者：何庆复 department of Mechanical Engineering Beijing Jiaotong University

The surface oxide film cracking behavior of Fe-30Ni-20Cr alloy under in-phase and out-of-phase synchronizing thermal cycling with mechanical cycling was *** oxide film cracking along the grain boundary under in-phase overlapping was creep predominant fracture *** induced slip lines preceding were accompanied by the surface oxide film cracking under Out-of phase,and the shear cracking was dominant *** mean stress could counteract a part of the tensile component of alternative stress,so as to delay the cracking process under in-phase,but positive mean stress overlapping the tensile alternative stress could accelerate the cycling cracking process under out-of-phase.

关键词： oxide film cracking in-phas out-of-phase cycling temperature cycling loading overlapping

Urban expressway traffic state forecasting based on multimode maximum entropy model

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Science china(Technological Sciences) 2010年第10期53卷 2808-2816页

作者： SUN XiaoLiang1,2, JIA LiMin1, DONG HongHui1, QIN Yong1 & GUO Min3 1State Key Laboratory of Rail Traffic Control and Safety, beijing jiaotong university, beijing 100044, china 2School of Traffic and Transportation, beijing jiaotong university, beijing 100044, china 3beijing Traffic Management Bureau, beijing 100044, china State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China School of Traffic and Transportation Beijing Jiaotong University Beijing China beijing Traffic Management Bureau Beijing China

The accurate and timely traffic state prediction has become increasingly important for the traffic participants,especially for the traffic managements. In this paper,the traffic state is described by Micro-LOS,and a direct prediction method is introduced. The development of the proposed method is based on Maximum Entropy (ME) models trained for multiple modes. In the Multimode Maximum Entropy (MME) framework,the different features like temporal and spatial features of traffic systems,regional traffic state are integrated simultaneously,and the different state behaviors based on 14 traffic modes defined by average speed according to the date-time division are also dealt with. The experiments based on the real data in beijing expressway prove that the MME models outperforms the already existing model in both effectiveness and robustness.

关键词： traffic state forecast maximum entropy model multimode

The Principal Eigenvalue for Jump Processes

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Acta Mathematica Sinica,English Series 2000年第3期16卷 361-368页

作者： Mufa Chen department of mathematics,beijing Normal university,beijing 100875,P.R.china department of mathematics Beijing Normal University Beijing 100875 P. R. China

A variational formula for the lower bound of the principal eigenvalue of general Markov jump processes is *** result is complete in the sense that the condition is fulfilled and the resulting bound is sharp for Markov... 详细信息

关键词： Principal eigenvalue Jump processes Variational formula for Dirichlet form