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TRACE AVERAGING DOMAIN DECOMPOSITION METHOD WITH NONCONFORMING FINITE ELEMENTS

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Journal of Computational mathematics 1996年第1期14卷 40-53页

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

We consider, in this paper, the trace averaging domain decomposition method for the second order self-adjoint elliptic problems discretized by a class of nonconforming finite elements, which is only continuous at the nodes of the quasi-uniform mesh. We show its geometric convergence and present the dependence of the convergence factor on the relaxation factor, the subdomain diameter H and the mesh parameter h. In essence;, this method is equivalent to the simple iterative method for the preconditioned capacitance equation. The preconditioner implied in this iteration is easily invertible and can be applied to preconditioning the capacitance matrix with the condition number no more than O((1 + In H/h)max(1 + H-2, 1 + In H/h)).

关键词： Math TRACE AVERAGING DOMAIN DECOMPOSITION METHOD WITH NONCONFORMING FINITE ELEMENTS

Moderate deviation for super-Brownian motion with immigration

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Science china mathematics 2004年第3期47卷 440-452页

作者： ZHANG Mei department of mathematics, beijing Normal university, beijing 100875, china department of mathematics, The Central university of Finance and Economics, beijing 100081, china department of mathematics Beijing Normal University Beijing China department of mathematics The Central University of Finance and Economics Beijing China

We prove a moderate deviation principle for a super-Brownian motion with immigration of all dimensions, and consequently fill the gap between the central limit theorem and large deviation principle.

关键词： moderate deviation principle super-Brownian motion with immigration large deviation principle evolution equation

CRITERION FOR JUDGING SATISFACTION OF CONSISTENCY CONDITIONS IN RATE-DEPENDENT CONSTITUTIVE RELATIONS

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Acta Mechanica Solida Sinica 1999年第4期12卷 356-364页

作者： Wang Zhe (College of Civil Engineering and Architecture,Northern jiaotong university,beijing 100044,china) Coll. of Civ. Eng. and Architecture Northern Jiaotong University Beijing 100044 China

Based on irreversible thermodynamics, the criterion for judging the satisfaction of consistency conditions in rate-dependent constitutive relationship is deduced by introducing four basic hypotheses. Formulas for solving internal variables are given. It makes the rate-dependent model applicable no matter whether the consistency conditions can be satisfied or not.

关键词： rate-dependent constitutive relations consistency condition irreversible thermodynamics

Performances of carbon nanotube field effect transistors with altered channel length

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Science china(Technological Sciences) 2010年第1期53卷 253-256页

作者： FENG Ying,HUANG ShiHua,KANG Kai & FENG YuGuang Institute of Optoelectronic Technology,beijing jiaotong university,beijing 100044,china Institute of Optoelectronic Technology Beijing Jiaotong University Beijing China

The influence of channel length on the performances of carbon nanotube field effect transistors(CNT-FETs) has been *** oxide etching was used to remove approximately a 60 nm layer from the original 100 nm silicon dioxide layer,to thin the dielectric layer of the back *** length of the CNT-FETs was changed along with the etching *** dependence of drain-source current on gate voltage was measured to analyze the performance of the CNT-FETs,including the transconductance,carrier mobility,current ON/OFF ratio,*** results indicate that the devices still keep good quality.

关键词： carbon nanotube field effect transistors mobility buffered oxide etching

REDUCTIONS OF ADJOINT REPRESENTATIONS TO LAX REPRESENTATIONS FOR CONSTRAINED FLOWS

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Chinese Annals of mathematics,Series B 1996年第2期17卷 187-198页

作者： ZENG YUNBO department of Applied mathematics, Tsinghua university, beijing 100084, china. 清华大学应用数学系北京

Within framework of zero-curvature representation theory, the Lax representations for x- andtn-constrained flows of soliton hierarchy are obtained from reductions of adjoint representationsof the auxiliary linear problems. This method is applied to the third order spectral problem bytaking modified Boussinesq hierarchy as an illustrative example.

关键词： Constrained flow Lax representation Adjoint representation Soliton hierarchy

METHOD OF NONCONFORMING MIXED FINITE ELEMENT FOR SECOND ORDER ELLIPTIC PROBLEMS METHOD OF NONCONFORMING MIXED FINITE ELEMENT FOR SECOND ORDER ELLIPTIC PROBLEMS

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Journal of Computational mathematics 2000年第5期18卷 449-456页

作者： Zhen-dong Luo (department of mathematics, Capital Normal university, beijing 100057, china) 首都师范大学北京 100037

In this paper, the method of non-conforming mixed finite element for second order elliptic problems is discussed and a format of real optimal order for the lowest order error estimate.

关键词： Non-conforming mixed finite element Error estimate Second order elliptic problems.

RST transforms resistant image watermarking based on centroid and sector-shaped partition

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Science china(Information Sciences) 2012年第3期55卷 650-662页

作者： ZHAO Yao1,2*, NI RongRong1,2* & ZHU ZhenFeng1,2* 1Institute of Information Science, beijing jiaotong university, beijing 100044, china 2beijing Key Laboratory of Advanced Information Science and Network Technology, beijing 100044, china Institute of Information Science Beijing Jiaotong University Beijing China beijing Key Laboratory of Advanced Information Science and Network Technology Beijing China

A novel digital watermarking scheme featuring centroid-based sectoring is proposed in this paper. To get higher robustness against geometric attacks, such as rotation, scaling, and translation (RST), a delicate synchronization mechanism was developed and incorporated into the proposed approach. During the process of watermark embedding, the original image was partitioned into sectors based on the image centroid. Synchronization information as well as the message bits is then embedded into these sectors. With the help of the centroid-based sectoring and synchronization information, the proposed approach is capable of restoring the correct sectoring even if it has experienced severe geometric distortion. This attribute ensures the correct recovery of embedded watermarks and contributes to the robustness of the proposed scheme. A series of experiments have been conducted to verify the feasibility and effectiveness of the proposed approach. Experimental results show that the proposed scheme possesses good robustness against RST attacks and considerable robustness against other common image processing attacks.

关键词： digital watermarking geometrical transform attacks RST transforms

The influence of thermal radiation on MHD station-point flow past a stretching sheet with heat generation

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Acta Mechanica Sinica 2011年第4期27卷 502-509页

作者： Jing Zhu.Lian-Cun Zheng.Xin-Xin Zhang department of mathematics and Mechanics,university of Science and Technology beijing,100083 beijing,china Thermal Engineering department,university of Science and Technology beijing,100083 beijing,china Zheng department of mathematics and Mechanics University of Science and Technology Beijing Beijing China Thermal Engineering department University of Science and Technology Beijing Beijing China

This letter is concerned with the plane and axisymmetric stagnation-point flows and heat transfer of an electrically-conducting fluid past a stretching sheet in the presence of the thermal radiation and heat generation or absorption. The analytical solutions for the velocity distribution and dimensionless temperature profiles are obtained for the various values of the ratio of free stream velocity and stretching velocity, heat source parameter, Prandtl number, thermal radiation parameter, the suction and injection velocity parameter and magnetic parameter and dimensionality index in the series form with the help of homotopy analysis method （HAM）. Convergence of the series is explicitly dis- cussed. In addition, shear stress and heat flux at the surface are calculated.

关键词： Thermal radiation MHD Laminar boundarylayers - Homotopy analysis method

Boundedness of Multilinear Operators in Herz-type Hardy Space

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Acta Mathematica Sinica,English Series 2000年第2期16卷 295-306页

作者： Lin Tang Dachun Yang department of mathematics,beijing Normal university,beijing 100875,P.R.china department of mathematics Beijing Normal University Beijing 100875 P. R. China

Let k ∈ *** prove that the lnultilinear operators of finite sums of products of singular integrals on Rn are bounded from H Kqlαl·pl（Rn）×…×HKqkαk,pk（Rn）into HKqα,p（Rn）if they have vanishing moments up to a certain order dictated by the target *** conditions on vanishing moments satisfied by the multilinear operators are also necessary when αj（?）0 and the singular integrals considered here include the Calderón-Zygmund singular integrals and the fractional integrals of any orders.

关键词： Multilinear operator Calderón-Zygmund operator Fractional integral Multiplier Herz space Hardy space Atom