一类拟线性椭圆型方程弱解梯度的一致估计

在区域Ω的边界满足一致p厚条件下,利用一致p厚的边界Sobolev不等式、一些容量不等式和一个精确的逆Hlder不等式,我们给出了一类拟线性椭圆型方程divAp(x,Du) Bp(x,u,Du)=f(x)弱解梯度的一致估计.     

平面调和映照Schwarz-Pick引理的一个表述

设w(z)=P[F](z)为定义在单位圆盘D上的调和映照,满足w(0)=0和w(D)D,其中F为边界函数.本文利用Poisson积分和方向导数得到w(z)的Schwarz-Pick引理的一个表述如下:A-w(z)≤maxo≤x≤1h(x,r),这里h(x,r)如(3.2)所示,为x的连续函数.进一步地,本文证明对于某些边界函数F,上述估计是精确的.     

具Hardy-Sobolev临界指数的奇异椭圆方程多解的存在性

运用变分方法研究了下面问题-Δpu=μupx(s)s-2u f(x,u),x∈Ω,u=0,x∈Ω,多重解的存在性,其中Ω是一个具有光滑边界的有界区域.     

计算柱面上对面积的曲面积分的一种新方法

给出了利用对弧长的曲线积分计算柱面上对面积的曲面积分的一种新方法,其计算公式为∫∫_Σf(x,y,z)dS=∫_(L*)ds∫z_1(x,y) z_2(x,y)f(x,y,z)dz,其中积分曲面Σ为垂直于xoy坐标面的柱面片,L*为Σ在xoy坐标面上的投影曲线(平面曲线),z=z1(x,y),z=z2(x,y)分别为过Σ的下边界曲线和上边界曲线的任一不同于Σ的曲面的方程.     

具有对流项的一类非线性椭圆型问题爆炸解的精确渐近行为

设Ω是RN中的有界光滑区域.应用Karamata正规变化理论和摄动方法.构造比较函数.得到了问题△u+|▽u|q=b(x)g(u),x∈Ω,u|(а)Ω=+∞的解在边界附近的精确渐近行为和解的唯一性,其中g在无穷远处以指数1+ρ(ρ＞0)正规变化.b在Ω内非负非平凡并且允许在边界为0.     

强奇系数拟线性拋物型方程的第一边值问题

本文在区域Q_T中考虑了拟线性抛物型方程第一边值问题:其中a_i和a分别满足而且g1≤g,g(x)∈L_m~(loc)(Ω),使得|f(x)|≤C或|φ_i(x)|≤C,例如g(x)=1/|x-x_0|或g(x)=ρ(x),在接近边界时ρ(x)～d~(-1)(x),d(x)表示x到边界Ω的距离,本文作者得到了这边值问题广义解的存在定理。     

插值逼近具边界数据的调和函数

该文考虑光滑闭Jondan曲线Γ围成的单连区域D,证明了在Γ上具有已知导数数据的D内调和函数u(x,y)的存在性.继而构造了一个调和插值多项式序列在(?)=D∪Γ上一致收敛于u(x,y),且具理想的收敛速度.此外,以往同类研究工作中的边界Γ是解析曲线,而在该文中已减少边界限制为Γ∈J_0.     

以Dirac测度为源的拟线性退化抛物方程

本文讨论拟线性退化抛物方程 ut-△um=δ(x), (A)(x,t)∈Q带有初值条件 u(x,0)=u0(x), (A)x∈Rn 的Cauchy问题,其中δ(x)是Dirac测度,m＞1,Q≡Rn×(0,+∞),u0(x)≥0,u0(x)∈Cβ(Rn),β∈(0,1)且0∈suppu0=-Ω,Ω是Rn中的一个有界开集,证明了弱解的存在性.此外,还讨论了自由边界的Holder连续性.     

Sobolev方程的基于H~1-Galerkin混合方法的新分裂格式

正1引言考虑如下Sobolev方程u_t-▽·(a(x)▽u_t+a(x)▽u)+u=f(x,t),(x,t)∈Ω×J,u(x,t)=0,(x,t)∈аΩ×J,(1)u(x,0)=u_0(x),x∈Ω.其中Ω是R~d(d=1,2,3)中具有边界     

多连通区域的黎曼-希尔伯特问题

<正> 设多连通有限区域 D 的边界为L=L_0+L_1+…+L_m,L 满足里雅普洛夫条件.本文研究下列齐次黎曼一希尔伯特问题:去找在 D 中单值解析且在 D+L 中连续的函数,F(z)=u(x,y)+iv(x,y)(z=(x+iy),满足下列边界     

BLOW-UP RATE OF POSITIVE SOLUTION OF UNIFORMLY PARABOLIC EQUATIONS WITH NONLINEAR BOUNDARY CONDITIONS

This paper deals with the blow-up of positive solutions of the uniformly pa-rabolic equations ut = Lu + a(x)f(u) subject to nonlinear Neumann boundary conditions . Under suitable assumptions on nonlinear functi-ons f, g and initial data U0(x), the blow-up of the solutions in a finite time is proved by the maximum principles. Moreover, the bounds of "blow-up time" and blow-up rate are obtained.     

GLOBAL BLOW-UP FOR A LOCALIZED DEGENERATE AND SINGULAR PARABOLIC EQUATION WITH WEIGHTED NONLOCAL BOUNDARY CONDITIONS

This paper deals with the blow-up properties of positive solutions to a localized degenerate and singular parabolic equation with weighted nonlocal boundary conditions. Under appropriate hypotheses, the global existence and finite time blow-up of positive solutions are obtained. Furthermore, the global blow-up behavior and the uniform blow-up profile of blow-up solutions are also described. We find that the blow-up set is the whole domain [0, a], including the boundaries, and this differs from parabolic equations with local sources case or with homogeneous Dirichlet boundary conditions case.     

Large Solutions to Elliptic Systems of $$\infty$$ -Laplacian Equations

Mathematical Notes - In this paper, we study the existence, uniqueness and boundary behavior of positive boundary blow-up solutions to the quasilinear system $$\Delta_{\infty}u=a(x)u^{p}v^{q}$$ ,...     

Blow-up for a degenerate parabolic equation with nonlocal source and nonlocal boundary

In this article, we investigate the blow-up properties of the positive solutions for a doubly degenerate parabolic equation with nonlocal source and nonlocal boundary condition. The conditions on the existence and nonexistence of global positive solutions are given. Moreover, we give the precise blow-up rate estimate and the uniform blow-up estimate for the blow-up solution.     

GLOBAL BLOW-UP FOR A DEGENERATE AND SINGULAR NONLOCAL PARABOLIC EQUATION WITH WEIGHTED NONLOCAL BOUNDARY CONDITIONS

This paper deals with the blow-up properties of positive solutions to a degenerate and singular nonlocal parabolic equation with weighted nonlocal boundary conditions.Under appropriate hypotheses, the global existence and finite time blow-up of positive solutions are obtained. Furthermore, by using the properties of Green's function, we find that the blow-up set of the blow-up solution is the whole domain(0, a), and this differs from parabolic equations with local sources case.     

Blow-up of solutions for a system of nonlocal singular viscoelastic equations

The main propose of this paper is to study the blow-up of solutions of an initial boundary value problem with a nonlocal boundary condition for a system of nonlinear singular viscoelastic equations. where the blow-up of solutions in finite time with nonpositive initial energy combined with a positive initial energy are shown.     

非局部边界条件的退化抛物方程组解的爆破和整体存在性

主要讨论具有非局部源与非局部边界条件的退化抛物型方程组,借助于上解与下解的技术,给出了该系统整体解的存在与有限时刻爆破的条件.此结果不仅扩充了已有的结论~([8]),而且表明,系数a,b和边界条件中的权重函数g_1(x,y),g_2(x,y),以及常数l_1,l_2在决定系统解的爆破与否中起着关键的作用.     

带非局部源的退化奇异半线性抛物方程的爆破

本文研究带齐次Dirichlet边界条件的非局部退化奇异半线性抛物方程ut-(xαux)x=∫0af(u)dx在(0,a)×(0,T)内正解的爆破性质,建立了古典解的局部存在性与唯一性.在适当的假设条件下,得到了正解的整体存在性与有限时刻爆破的结论.本文还证明了爆破点集是整个区域,这与局部源情形不同.进而,对于特殊情形:f(u)=up,p>1及,f(u)=eu,精确地确定了爆破的速率.     

Blow-up solutions and global solutions for nonlinear parabolic problems

This paper deals with the blow-up of positive solutions for a nonlinear parabolic equation subject to nonlinear boundary conditions. We obtain the conditions under which the solutions may exist globally or blow up in a finite time, by a new approach. Moreover, upper estimates of the “blow-up time”, blow-up rate and global solutions are obtained also.     

Singular solutions of perturbed logistic-type equations

We are concerned with the qualitative analysis of positive singular solutions with blow-up boundary for a class of logistic-type equations with slow diffusion and variable potential. We establish the exact blow-up rate of solutions near the boundary in terms of Karamata regular variation theory. This enables us to deduce the uniqueness of the singular solution.