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Science china Chemistry 2004年第6期47卷 507-511页

作者： LI Li1, WU Qingsheng1 DING Yaping2 & LI Ping3 1. department of Chemistry, tongji university, shanghai 200092, china 2. department of Chemistry, shanghai university, shanghai 200436, china 3. department of Food, Anhui Agricultural university, Hefei 230036, china 1. department of Chemistry Tongji University 200092 Shanghai China 2. department of Chemistry Shanghai University 200436 Shanghai China 3. department of Food Anhui Agricultural University 230036 Hefei China

Multi-armed nanorods and nanobars of semiconductor selenium were simultane- ously synthesized in the light of biomineralization process through bio-membrane bi-templates of rush at room temperature. The multi-armed nanorods are 60 nm in diameter and 1.5 μm in length; the nanobars are 150 nm in diameter and 1000—1100 nm in length. The XRD pattern indicates that these nanocrystals were crystallized in the hexagonal structure with lattice constants a = 0.437 nm, c = 0.495 nm. The possible formation mechanism was investigated.

关键词： selenium, multi-armed nanorods, nanobars, bio-membrane, bi-templates.

FINITENESS CONDITIONS FOR GENERALIZED EXPONENTS OF DIGRAPHS

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Chinese Annals of mathematics,Series B 1998年第4期19卷 453-464页

作者： SHAO JIAYU (department of Applied mathematics, Tonsil university, shanghai 200092, china.)WU XIAOJUN (Project supported by the National Natural Science FOundation of china and shanghai Science anda’echnolgy Developing FOundation.) tongji Univ Dept Appl Math Shanghai 200092 Peoples R China

Necessary and sufficient conditions are given for the finiteness of the generalized exponents expD(k), f(D, k) and F(D, k) for digraphs which are not necessarily primitive. Also the largest finite value of the generalized exponent expD(k) for digraphs of order n is determined and the complete characterizations of the extreme digraphs are given.

关键词： Finiteness condition Generalized exponent Digraph

ON ABELIAN AUTOMORPHISM GROUPS OF SURFACES OF GENERAL TYPE

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Chinese Annals of mathematics,Series B 1996年第1期17卷 43-52页

作者： CAI JINXING(department of mathematics, East china Normal university, shanghai 200062, china.) E china NORMAL UNIV DEPT MATHSHANGHAI 200062PEOPLES R CHINA

It is proved that for a complex minimal smooth projective surface S of general type, its abelian automorphism group is of order≤36k2s+24, provided x(os)≥8, where Ks is the canonical divisor of S, and X(Os) the Euler... 详细信息

关键词： Projective surface Automorphism group Canonical divisor

LIFE-SPAN OF CLASSICAL SOLUTIONS TO ONE DIMENSIONAL NONLINEAR WAVE EQUATIONS

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Chinese Annals of mathematics,Series B 1992年第3期13卷 266-279页

作者：李大潜俞新周忆 Institute of mathematics Fudan UniversityShanghai 200433China. department of Applied mathematics Tongji UniversityShanghai 200092China.

By means of a simple and direot method,the authors obtain the sharp lower bound ofthe life-span of classioal solutions to the Cauohy problem with small initial data for onedimensional fully nonlinear wave equations ut... 详细信息

关键词： WAVE sharp affine verified 云一岁夕 integer applying desired satisfy

Physically based simulation of Buddha Glory

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Progress in Natural Science:Materials International 2006年第6期16卷 656-662页

作者： LIU Shiguang, WANG Zhangye, GONG Zheng, WANG Changbo and PENG Qunsheng (State Key Laboratory of CAD&CG, Zhejiang university, Hangzhou 310027, china department of mathematics, Zhejiang university, Hangzhou 310027, china department of Structure Engineering, tongji university, shanghai 200092, china) [a]State Key Laboratory of CAD&CG Zhejiang University Hangzhou China [b]department of mathematics Zhejiang University Hangzhou China [c]department of Structure Engineering Tongji University Shanghai China

This paper proposes a novel method of photorealistic simulation of Buddha Glory, a natural phenomenon of great visual beauty which can be observed in the area of famous Buddhism Holy Lands in china. This phenomenon is mainly caused by back-scattering of water droplets in fog or cloud. To simulate the glory, we first calculate the spectral scatter intensity of glory rings using Mie scattering theory. We then present a new shadow model to determine the deformed shape of the head and body of "Buddha" within the glory ring. The affect of atmospheric parameters such as the solar elevation angles, the density and size of water droplet in fog or cloud on the shape and color of Buddha Glory is also calculated. For rendering, we adopt the method of path scattering integral to generate the whole attenuated scene of Buddha Glory. Compared with the photographs of real Buddha Glory displays, our synthetic results are quite satisfactory.

关键词： natural phenomenon Buddha Glory back-scattering physically based simulation.

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 1. School of Civil Engineering Beijing Jiaotong University Beijing 100044 China2. College of Civil Engineering Tongji University Shanghai 200092 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

Rigidity of Proper Self-Mapping on Some Kinds of Generalized Hartogs Triangle

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Acta Mathematica Sinica,English Series 2002年第2期18卷 357-362页

作者： CHEN Zhi Hua XU De Kang Applied mathematics department.tongji university.shanghai 200092.P.R.china E-mail:zzzhhc@*** dekangxu@*** Applied mathematics department Tongji University Shanghai P.R. China

It is proved that every proper holomorphic self-mapping of some kinds of Generalized Hartogs Triangles is an *** its explicit expression is given.

关键词： Reinhardt domain Proper mapping Rigidity

Boundary element-free method for elastodynamics

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Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 641-657页

作者： CHENG Yumin1 & PENG Miaojuan2 1. shanghai Institute of Applied mathematics and Mechanics, shanghai university, shanghai 200072, china 2. department of Civil Engineering, shanghai university, shanghai 200072, china 1. shanghai Institute of Applied mathematics and Mechanics Shanghai University 200072 Shanghai China 2. department of Civil Engineering Shanghai University 200072 Shanghai China

The moving least-square approximation is discussed first. Sometimes the method can form an ill-conditioned equation system, and thus the solution cannot be obtained correctly. A Hilbert space is presented on which an orthogonal function system mixed a weight function is defined. Next the improved moving least-square approximation is discussed in detail. The improved method has higher computational efficiency and precision than the old method, and cannot form an ill-conditioned equation system. A boundary element-free method (BEFM) for elastodynamics problems is presented by combining the boundary integral equation method for elastodynamics and the improved moving least-square approximation. The boundary element-free method is a meshless method of boundary integral equation and is a direct numerical method compared with others, in which the basic unknowns are the real solutions of the nodal variables and the boundary conditions can be applied easily. The boundary element-free method has a higher computational efficiency and precision. In addition, the numerical procedure of the boundary element-free method for elastodynamics problems is presented in this paper. Finally, some numerical examples are given.

关键词： moving least-square approximation, improved moving least-square approximation, elastodynamics, boundary integral equation, meshless method, boundary element-free method, Fourier eigen transform.

AN INVERSE EIGENVALUE PROBLEM FOR JACOBI MATRICES

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Journal of Computational mathematics 2003年第5期21卷 569-584页

作者： Er-xiong Jiang (department of mathematics, shanghai university, shanghai 200436, china) department of mathematics Shanghai University 上海 200436

Let T1,n be an n x n unreduced symmetric tridiagonal matrix with eigenvaluesand is an (n - 1) x (n - 1) submatrix by deleting the kth row and kth column, k = 1, 2,be the eigenvalues of T1,k andbe the eigenvalues of Tk+1,nA new inverse eigenvalues problem has put forward as follows: How do we construct anunreduced symmetric tridiagonal matrix T1,n, if we only know the spectral data: theeigenvalues of T1,n, the eigenvalues of Ti,k-1 and the eigenvalues of Tk+1,n?Namely if we only know the data: A1, A2, An,how do we find the matrix T1,n? A necessary and sufficient condition and an algorithm ofsolving such problem, are given in this paper.

关键词： Symmetric tridiagonal matrix Jacobi matrix Eigenvalue problem Inverse eigenvalue problem.

An improvement in stability of delay difference systems

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Chinese Science Bulletin 1998年第7期43卷 544-547页

作者： ZHANG Shunian department of Applied mathematics, shanghai Jiaotong university, shanghai 200240, china department of Applied mathematics Shanghai Jiaotong University Shanghai China

A new result on the stability of delay difference equations is established, in which a kind of weighted norm for x is adopted in order to estimate the upper bound of Liapunov functional.

关键词： delay difference systems uniform asymptotic stability in terms of two measures Liapunov functionals.