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A MULTISTEP FINITE VOLUME METHOD WITH PENALTY FOR THERMAL CONVECTION PROBLEMS IN TWO OR THREE DIMENSIONS

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Journal of Systems Science & Complexity 2008年第1期21卷 129-143页

作者： Min YANG department of mathematics Yantai University Yantai 264005 China

The author considers a thermal convection problem with infinite Prandtl number in two or three dimensions. The mathematical model of such problem is described as an initial boundary value problem made up of three partial differential equations. One equation of the convection-dominated diffusion type for the temperature, and another two of the Stokes type for the normalized velocity and pressure. The approximate solution is obtained by a penalty finite volume method for the Stokes equation and a multistep upwind finite volume method for the convection-diffusion equation. Under suitable smoothness of the exact solution, error estimates in some discrete norms are derived.

关键词： Error estimate finite volume thermal convection problem unstructured meshes.

The regular representation and regular covariant representation of crossed products of Woronowicz C^(*)-algebras

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Science china mathematics 2005年第9期48卷 1245-1259页

作者： ZHANG Xiaoxia~(1,2. & GUO Maozheng~(1,3) 1. School of Mathematical Sciences,Peking university,Beijing 100871,china {2.,yantai university,yantai 2.4005,china 3. LMAM,Peking university,Beijing 100871,china School of Mathematical Sciences Peking University Beijing China department of mathematics Yantai University Yantai China LMAM Peking University Beijing China

In this paper,it is shown that the regular representation and regular covariant representation of the crossed products A×α G correspond to the twisted multiplicative unitary operators,where A is a Woronowicz C~*-algebra acted upon by a discrete group ***,it is also shown that the regular covariant C~*-algebra is the Woronowicz C~*-algebra which corresponds to a multiplicative ***,an explicit description of the multiplicative unitary operator for C(SU_q(2. )×α (?) is given in terms of those of the Woronowicz C~*-algebra C(SU_q(2. ) and the discrete group G.

关键词： multiplicative unitary operator, Woronowicz C*-algebra, crossed product.

Prediction and Control of Both Wrinkle Limit and Fracture Limit on Cylindrical Cup Deep-Drawing

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International Journal of Minerals,Metallurgy and Materials 1998年第4期12卷 237-240,250页

作者： Junxiang Lei(department of Mechanical Enginecring, yantai university, {2.2.4005,china) department of Mechanical Engineering Yantai University Yantai 264005 China

hased on both the wrinkle model and fracturc model, the wrinkle critical tangent pressure and the fractureon critical radial tensile stress are calculated respectively. The maximum tangent pressure formula in the flange deformation zone and the maximum radial tensile stress formula in the cylinder-wall pass force zone are given, and both theno-wrinkle limitl criterion and no-fracture limit criterion are put froward. The prediction and control criterion anddiagram of both the wrinkle limit and fracture limit on cylindrical cup deep-drawing, the most suitable formingzone and the limit deep-drawing coefficient are obtained. Comparing with present experience formulae and actualproduct's production, this prediction and control are quite accurate.

关键词： cylindrical cup deep-drawing wrinkle limit fracture limit deep-drawing limit

The influence of laser pulse on the photoabsorption spectra of Li atom in strong external field

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Science china(Physics,Mechanics & Astronomy) 2006年第2期49卷 178-186页

作者： WANG Dehua1 & LIN Shenglu2.1. School of Physics and Electronic Engineering, yantai Normal university, yantai 2.402., china 2. department of Physics, Shandong Normal university, Jinan 2.0014, china School of Physics and Electronic Engineering Yantai Normal University Yantai China department of Physics Shandong Normal University Jinan China

Using the time-dependent perturbation theory and the calculation formula of the single- and double-pulse absorption spectra of the atom in strong external fields, we calculate the single- and double-pulse absorption spectra of Li atom in strong magnetic field for different pulse widths. The results show that a pulse of some width can reduce the contribution of the short period closed orbits and eliminate the contribution of the long period orbits. Compared with the single-pulse absorption spectra, we found that for some phase differences, the double-pulse laser absorption spectra are strengthened; while for others, they are reduced. Therefore, we can use the pulse laser to control the oscillation of the absorption spectra and obtain the optimization object.

关键词： laser pulse closed orbit absorption spectra.

Internal noise stochastic resonance in CO oxidation on nm-sized palladium particles

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Science china Chemistry 2005年第5期48卷 395-401页

作者： GONG Yubing1,2. HOU Zhonghuai1 & XIN Houwen1 1. department of Chemical Physics, university of Science and Technology of {2., Hefei 2.002., {2. 2. department of Physics, yantai Teachers university, yantai 2.402., {2. department of Chemical Physics University of Science and Technology of China Hefei China department of Physics Yantai Teachers University Yantai China

Based on a stochastic mesoscopic model, the influence of internal noise on the oscillatory kinetics of the catalytic oxidation of CO on nm-sized palladium particles is studied, using the chemical Langevin equations, Poisson approximation algorithm, and exact stochastic simulation algorithm. The reaction rate oscillations are of stochastic nature due to considerable internal noise in such mesoscopic systems. It is found that the performance of the stochastic oscillations undergoes a maximum with the variation of internal noise level for a given CO partial pressure, which demonstrates the occurrence of internal noise stochastic resonance. This phe-nomenon implies that optimal internal noise would favor the reaction rate oscillation of CO oxi-dation on nm particles. Such a phenomenon is robust to the change of external parameters, such as CO pressures.

关键词： nanometer-sized palladium particles, surface catalytic CO oxidation, internal noise, stochastic resonance, chemical Langevin equation.

Stochastic resonance in surface catalytic oxidation of carbon monoxide induced by colored noise

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Science china Chemistry 2004年第2期47卷 106-112页

The dynamical behavior of surface catalytic oxidation reaction of Pt(110)/CO+O2.modulated by colored noise, under the condition of specific temperature, has been investigated when the partial pressure of CO gas is near the supercritical Hopf bifurcation point. By computer simulation the oscillation and stochastic resonance induced by colored noise are observed. The influences of the intensity and correlation time of colored noise on stochastic resonance are discussed. The range of sensitivity of the system to the environmental fluctuation is analyzed.

关键词： colored noise, stochastic resonance, surface catalytic reaction of Pt(110)/CO+O2. supercritical Hopf bifurcation, signal-to-noise ratio (SNR).

The cohomology group of weak entwining structure

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Science china mathematics 2007年第5期50卷 665-674页

作者： Ling JIA & Fang LI department of mathematics, Ludong {2., yantai 2.402., china department of mathematics, Zhejiang {2., Hangzhou 31002., china department of mathematics Ludong University Yantai China department of mathematics Zhejiang University Hangzhou China

In this paper, we reveal that a weak entwining structure admits a rich cohomology theory. As an application we compute the cohomology of a weak entwining structure associated to a weak coalgebra-Galois extension.

关键词： weak entwining structure cohomology group 16W80 16W99

A Fixed Point Theorem and an Equilibrium Point of an Abstract Economy in H-spaces

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Acta Mathematicae Applicatae Sinica 2003年第3期19卷 425-430页

作者： Ji-cheng Houdepartment of mathematics, Shantou {2., Shantou 515063, chinaCorrespondence address: department of mathematics and Information Science, yantai university, yantai2.4005, china department of mathematics Shantou University Shantou China

In this note we first prove a fixed point theorem in H-spaces which unities and extends the corresponding results in [6] and [9]. Then, by applying the fixed point theorem, we prove an existence theorem of an equilibr... 详细信息

关键词： H-space fixed points abstract economy non-compact domain Nash equilibria compactly open lower sections

GENERAL CAUCHY PROBLEM FOR THE LINEAR SHALLOW-WATER EQUATIONS ON AN EQUATORIAL BETA-PLANE

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Journal of Hydrodynamics 2006年第3期18卷 303-309页

作者： SHEN Chun SHI Wei-hui School of mathematics and Information Yantai Normal University Yantai 264025 China Shanghai Institute of Applied mathematics and Mechanics Shanghai University Shanghai 200072 China department of mathematics Shanghai University Shanghai 200444 China

Based on the theory of stratification, the well-posedness of the initial value problem for the linear shallow-water equations on an equatorial beta-plane was discussed. The sufficient and necessary conditions of the existence and uniqueness for the local solution of the equations were presented and the existence conditions for formal solutions of the equations vere also given. For the Cauchy problem on the hyper-plane {t = O}, the local analytic solution were worked out and a special case was discussed. Finally, an example was used to explain the variety of formal solutions for the ill-posed problem.

关键词： stratification initial value problem,well-posedness shallow-water equations