一维半导体量子能量输运模型稳态解的唯一性

本文研究了一维半导体稳态量子能量输运模型的古典解.利用一些不等式技巧证明了当晶格温度充分大且电流密度较小时其解是唯一的,这在文献[3]中没有得到.     

不可压液晶模型经典解的存在性（英文）

本文研究一个描述离子在向列型液晶中输运和扩散的非线性偏微分方程模型.该模型耦合了对应于电势满足Maxwell’s方程的离子的连续性方程的Nernst-Planck系统,控制液晶流演变的不可压Naiver-Stokes方程与关于液晶方向场的非线性Allen-Cahn型方程.我们利用能量方法证明了该系统的大初值经典解的局部存在性和小初值经典解的整体存在性.     

三次自催化模型的整体解

该文利用重要不等式及能量积分方法首先得到了解的初等的先验估计．然后利用线性半群的有关性质及精细计算得到了解的最大模估计，从而证明了两类三次自催化模型在Dirichlet边界条件下整体解的存在性，并进而证明了第一类模型的最大吸引子的存在性．     

一维半导体流体动力学模型的局部有界解

本文讨论了能量方程是压力一密度关系的一维半导体流体动力学模型方程,通过把欧拉－泊松方程变成拟线性波动方程,利用拟线性波动方程的局部解存在性,得到一维半导体流体动力学模型的局部解,并且解是有界的。     

一类广义KdV－Burgers型方程的初边值问题

本文研究了一类带三阶粘性项的广义ＫｄＶ－Ｂｕｒｇｅｒｓ型方程的初边值问题．运用Ｇａｌｅｒｋｉｎ逼近方法，结合能量估计，得到了问题整体解的存在性，正则性，唯一性和稳定性等结果．并在一定条件下讨论了问题的解的渐近行为和“爆破”现象．     

非线性中子输运方程的Galerkin有限元解

§1.引言在核反应系统中,当中子数目足够多时,中子间的相互作用必须考虑,这就导致非线性中子输运方程。在这方面,已出现了一些研究工作,文献[1]对一类非线性中子输运方程,在一定的假定下,用半群方法证明了它的初边值问题解的存在性和唯一性。本文试图用[2]中的方法考察非线性中子输运方程的Galerkin有限元解。在§2中,给出了解的先验估计。在§3中,利用解的先验估计给出了广义解的存在性,构造了Galer-     

一个耦合双曲-抛物系统的全局光滑解

考虑一个源自生物学的耦合双曲-抛物模型的初边值问题.当动能函数为非线性函数以及初始值具有小的L~2能量但其H~2能量可能任意大时,得到了初边值问题光滑解的全局存在性和指数稳定性.而且,如果假定非线性动能函数满足一定的条件,在对初值没任何小条件假定下得到光滑解的全局存在性.通过构造一个新的非负凸熵和做精细的能量估计得到了结果的证明.     

基于交叉变分的非线性Klein—Gordon方程解的整体存在和爆破

研究非线性Klein-Gordon方程的初边值问题,运用位势井方法,在E(0)d的情况得到了方程解的整体存在和爆破.在临界能量状态得到了整体解的存在性与不存在性.最后使用凸性方法,得到某些具有高初始能量解的爆破.     

一类带小参数反应——扩散型方程组的性态估计

得到了激光等离子能量交换模型研究中的一类反应－－扩散方程组的本解的存在性。并通过引进光滑符号函数对解析解的性态进行了估计,为数值方法的误差分析提供了理论依据。     

一类多重非线性抛物方程组解的整体不存在性

本文研究了一类多重非线性抛物方程组初边值问题解的整体不存在性,利用修正的能量扰动法,得到了正初始能量解的整体不存在性结果.     

Initial boundary value problems for a quantum hydrodynamic model of semiconductors: Asymptotic behaviors and classical limits

The present paper proves the existence and the asymptotic stability of a stationary solution to the initial boundary value problem for a quantum hydrodynamic model of semiconductors over a one-dimensional bounded domain. We also discuss on a singular limit from this model to a classical hydrodynamic model without quantum effects. Precisely, we prove that a solution for the quantum model converges to that for the hydrodynamic model as the Planck constant tends to zero. Here we adopt a non-linear boundary condition which means quantum effect vanishes on the boundary. In the previous researches, the existence and the asymptotic stability of a stationary solution are proved under the assumption that a doping profile is flat, which makes the stationary solution also flat. However, the typical doping profile in actual devices does not satisfy this assumption. Thus, we prove the above theorems without this flatness assumption. Firstly, the existence of the stationary solution is proved by the Leray-Schauder fixed-point theorem. Secondly, we show the asymptotic stability theorem by using an elementary energy method, where the equation for an energy form plays an essential role. Finally, the classical limit is considered by using the energy method again.     

On the existence and uniqueness of a generalized solution of the mixed problem for the wave equation with the second and third boundary conditions

We prove the uniqueness of a generalized solution of an initial-boundary value problem for the wave equation with boundary conditions of the third and second kind. In addition, we find a closed-form expression for the analytic solution of that problem with zero initial data. The result plays an important role in the investigation of the boundary control problem. We show how to use the obtained solution for the investigation of the boundary control problem in the case of subcritical time intervals for which the solution of the boundary control problem, if it exists at all, is unique. We obtain necessary and sufficient conditions for the existence of a unique solution in a class admitting the existence of finite energy.     

ON INTERACTION OF SHOCK AND SOUND WAVE （II）

Ｉｎｔｈｉｓｐａｐｅｒｗｅｃｏｎｔｉｎｕｅｏｕｒｄｉｓｃｕｓｓｉｏｎｉｎ[5].Ｍａｉｎｌｙｗｅｗｉｌｌｅｓｔａｂｌｉｓｈａｐｒｉｏｒｉｅｓｔｉｍａｔｅｓｆｏｒｔｈｅｌｉｎｅａｒｉｚｅｄｐｒｏｂｌｅｍ(Ｇ),ａｎｄｔｈｅｎｐｒｏｖｅｔｈｅｅｘｉｓｔｅｎｃｅｏｆｔｈｅｓｏｌｕｔｉｏｎｔｏｎｏｎｌｉｎｅａｒｐｒｏｂｌｅｍ.Ｉｎ§5ｗｅｇｉｖｅｓｏｍｅｔｅｃｈｎｉｃａｌｐｒｅｐａｒａｔｉｏｎｓ.Ｔｈｅｎｔｈｅｗｈｏｌｅ§6ｉｓｄｅｖｏｔｅｄｔｏｔｈｅｅｓｔａｂｌｉｓｈｍｅｎｔｏｆｅｎｅｒｇｙｅｓｔｉｍａｔｅｓ.Ｉ…     

The heat flow and harmonic maps between complete manifolds

We consider the existence, uniqueness and convergence for the long time solution to the harmonic map heat equation between two complete noncompact Riemannian manifolds, where the target manifold is assumed to have nonpositive curvature. As an application, we solve the Dirichlet problem at infinity for proper harmonic maps between two hyperbolic manifolds for a class of boundary maps. The boundary map under consideration has finite many points at which either it is not differentiable or has vanishing energy density.     

Global existence and uniform decay of solutions for a system of wave equations with dispersive and dissipative terms

In this paper, we consider a system of two coupled wave equations with dispersive and viscosity dissipative terms under Dirichlet boundary conditions. The global existence of weak solutions as well as uniform decay rates (exponential one) of the solution energy are established.     

具交叉感染的流行病模型的数学分析

In this paper,an initial boundary value problem with homogeneous Neumann boundary condition is studied for a reaction-diffusion system which models the spread of infectious diseases within two population groups by means of self and criss-cross infection mechanism. Existence,uniqueness and boundedness of the nonnegative global solution (u1,u2,u3,u4),existence of the limit of the solution as t→+∞,namely,(u1,u2,u3,u4)→(u*1,0,u*3,0),are proved.     

Some properties of strong solutions to nonlinear heat and moisture transport in multi-layer porous structures

The present paper deals with mathematical models of heat and moisture transport in layered building envelopes. The study of such processes generates a system of two doubly nonlinear evolution partial differential equations with appropriate initial and boundary conditions. The existence of the strong solution in two dimensions for a (short) time interval is proven. The proof rests on regularity results of elliptic transmission problem for isotropic composite materials.     

Mathematical analysis of some new Reynolds‐rod elastohydrodynamic models

In this paper, some new elastohydrodynamic Reynolds‐rod models are posed to obtain the existence of solution (the lubricant pressure and the elastic rod displacement). More precisely, a sign restriction on fluid pressure for cavitation modelling and different unilateral conditions on the rod displacement associated with a rigid structure coating are formulated in terms of coupled variational inequalities. The particular hinged or clamped boundary conditions on the rod displacement require different techniques to prove the existence of solution. Besides nearly linear coupled problems, two non‐linear rod problems including curvature effects are analysed. Mainly, regularity results and L^∞ estimates for the solution of variational inequalities and fixed‐point theorems lead to the existence results for the various coupled models. Copyright © 2001 John Wiley & Sons, Ltd.     

Stationary convection–diffusion equation in an infinite cylinder

We study the existence and uniqueness of a solution to a linear stationary convection–diffusion equation stated in an infinite cylinder, Neumann boundary condition being imposed on the boundary. We assume that the cylinder is a junction of two semi-infinite cylinders with two different periodic regimes. Depending on the direction of the effective convection in the two semi-infinite cylinders, we either get a unique solution, or one-parameter family of solutions, or even non-existence in the general case. In the latter case we provide necessary and sufficient conditions for the existence of a solution.