EXISTENCE OF WEAK SOLUTIONS FOR A DEGENERATE GENERALIZED BURGERS EQUATION WITH LARGE INITIAL DATA

11MroduCtlonIn this paper we will investigate the global exlstence ofwe欢 solutions to a de欧nerate辟nerajlzed Bur驴d equatllJll in the formut ＋(。侧。＝t。。。,x E R‘,t＞0(1．1)with the initial data刚,x)一。。卜 卜)(1．1)is not only a means to study hxPerbolic conser、nonl。s[1,2]but also the mathematicalmodel of*the*、 propapatlon offinlt。。plltude sound w。es in、i劝l。area ofduct(see[3;4]),where u is an roustlc vrable,with the linear effects of chang6s!n the duct area taken out;andt I…     

EXISTENCE AND UNIQUENESS OF WEAK SOLUTIONS FOR TWO-DIMENSIONAL MODIFIED NAVIER-STOKES EQUATIONS

This paper studies a two-dimensional modified Navier-stokes equations. The author shows the existence and uniqueness of weak solutions for this equation by Galerkin method in bounded domains. The result is further extended to the case of unbounded channel-like domains.     

EXISTENCE OF WEAK SOLUTIONS TO A DEGENERATE STEAD-STATE SEMICONDUCTOR EQUATIONS

In this paper, we consider a degenerate steady-state drift-diffusion model for semiconductors. The pressure function used in this paper is ()(s) = s~α(α > 1). We present existence results for general nonlinear diffhsivities for the degenerate Dirichlet-Neumann mixed boundary value problem.     

EXISTENCE AND NONEXISTENCE OF GLOBAL POSITIVE SOLUTIONS FOR DEGENERATE PARABOLIC EQUATIONS IN EXTERIOR DOMAINS

This article deals with the degenerate parabolic equations in exterior domains and with inhomogeneous Dirichlet boundary conditions. We obtain that pc = (σ+m)n/(n-σ-2) is its critical exponent provided max{-1, [(1-m)n-2]/(n+1)} σ n-2. This critical exponent is not the same as that for the corresponding equations with the boundary value 0, but is more closely tied to the critical exponent of the elliptic type degenerate equations. Furthermore, we demonstrate that if max{1, σ + m} p ≤ pc, then every positive solution of the equations blows up in finite time; whereas for ppc, the equations admit global positive solutions for some boundary values and initial data. Meantime, we also demonstrate that its positive solutions blow up in finite time provided n ≤σ+2.     

EXISTENCE AND NONEXISTENCE OF GLOBAL SOLUTIONS OF THE INITIAL-BOUNDARY VALUE PROBLEM FOR SOME DEGENERATE HYPERBOLIC EQUATION

The author considers the global existence and global nonexistence of the initial-boundary value problem for some degenerate hyperbolic equation of the form utt- div(|▽u|p-2▽u)= |u|mu, (x,t) ∈ [0, ∞) ×Ωwith p ＞ 2 and m ＞ 0. He deals with the global solutions by D.H.Sattinger's potential well ideas. At the same time, when the initial energy is positive, but appropriately bounded,the global nonexistence of solutions is verified by using the analysis method.     

GLOBAL EXISTENCE OF WEAK SOLUTIONS TO THE

We consider the quantum Navier-Stokes equations for the viscous, compressible, heat conducting fluids on the three-dimensional torus T³. The model is based on a system which is derived by Jungel, Matthes and Milisic [15]. We made some adjustment about the relation of the viscosities of quantum terms. The viscosities and the heat conductivity coefficient are allowed to depend on the density, and may vanish on the vacuum. By several levels of approximation we prove the global-in-time existence of weak solutions for the large initial data.     

带线性退化阻尼项的可压缩欧拉方程组的整体正规解

本文研究了理想气体的带线性退化阻尼项的可压缩欧拉方程组的真空初值问题.利用能量估计的方法,在适当的初始条件下,获得了初值问题的正无偏见解整体存在的结果.推广了可压缩等熵欧拉方程组的结果.     

R^N中的非线性退化椭圆方程粘性解的存在性

本文研究了Ｒ＾Ｎ中的非线性退化椭圆型方程Ｆ（Ｄｕ，Ｄ＾２ｕ）＋ｕｓ＝ｆ的非负粘性解的存在性，其中ｓ〉０，Ｆ满足某些关于ｐ的条件，本文在下面的条件下证明了存在性；１．ｓ〉ｐ－１，ｆ在无穷远处不需要增长条件；２．０〈ｓ≤ｐ－１，ｆ在无穷远处具有某种增长条件。     

THE REGULAR SOLUTIONS OF THE ISENTROPIC EULER EQUATIONS WITH DEGENERATE LINEAR DAMPING

The regular solutions of the isentropic Euler equations with degenerate linear damping for a perfect gas are studied in this paper. And a critical degenerate linear damping coefficient is found, such that if the degenerate linear damping coefficient is larger than it and the gas lies in a compact domain initially, then the regular solution will blow up in finite time; if the degenerate linear damping coefficient is less than it, then under some hypotheses on the initial data, the regular solution exists globally.     

EXISTENCE OF WEAK SOLUTIONS OF 3-D EULER EQUATIONS WITH AXIAL SYMMETRV

1IntroductionInthispaper,weconsidertilefollowillgeqllatiolls:wilerstheunknownfullctionsarevelocityfields'd(x.t)=(.UI(x.t)..uZ(x.t)..it3(x,t))itlldscalarpressurefunctiollp(x,t).Asweallknow,(1.l)istheNavier-Stokesequatiollswithviscosityealld(1.2)istheEulerequationsobtainedbyvanishingtheviscosityill(1.1).Tilershavebeedalargellumberofresultsabout2-DEulerequatiolls.Butillthreedilllellsioll,illersisstillfewresults.TillsispartiallybecauseofthefactthattwodillleusiollalNavier-Stokescquatiollshasbe…     

一类非线性渗流方程Cauchy问题弱解的存在唯一性

讨论具强非线性源和对流项的一般渗流方程以Ｒ＾Ｎ中某一Ｒａｄｏｎ测度为初始迹的Ｃａｕｃｈｙ问题弱解的存在唯一性。     

EXISTENCE OF WEAK SOLUTIONS OF ORDINARY DIFFERENTIAL EQUATIONS IN BANACH SPACES

0 IntroductionRecently, the study of ordinary differential equations in a Banach spacehas been developed extensively by using the strong topology, see [2],13],[4]. Atpresent, however, there is no reference or paper which systematically studiesweak solutions of the Cauchy problem of ordinary differential equation in theweak topology. In references [l],15],[7] and [8], several results of weak solutionsare proved. In this paper, we shall give the other results of weak solutions,some of which are…     

REMARKS ON THE EXISTENCE OF WEAK SOLUTIONS TO 2-D INCOMPRESSIBLE NAVIER-STOKES EQUATIONS

1.IntroductionConsiderthefollowinghomogeneous2-DincompressibleNavier-Stokesequations:whereV=(VI(t,x),VZ(t,x))isthevelocityofthefluid,Pisthescalarpressure,V'V=V101 V202,andtheconstantu>0isthekineticviscosityofthefluid(whenu=0,thissystemiscalledEulerequations,andwedenoteitby(1.1)).Byactingtheoperationofcurlon(1.1),wecanobtaintheevolutionequationforvorticityw=(a1VZ--02VI).Itisthevorticity-streamformof(1.1)(whenu=0,wedenoteitby(1.2)).For(1.1),in[4],R.DipernaandA.Majdaprovedtheglobalexiste…     

EXISTENCE AND UNIQUENESS OF SOLUTIONS TO A CLASS OF NONLINEAR FRACTIONAL ORDER DIFFERENTIAL EQUATIONS WITH DELAY

A class of nonlinear fractional order differential equations with delay is investigated in this paper. Using Leray-Schauder fixed point theorem and the contraction mapping theorem, we obtain some sufficient conditions for the existence and uniqueness of solutions to the fractional order differential equations.     

蜕化抛物型方程广义解的界性

解的有界性为探讨解的正则性所必需。本文在很一般的结构条件下证明下面方程(1)的广义解的有界性,并对(1)的一种特殊情形作出广义解最大模的光验估计。这是椭圆型方程相应结果的推广。设G为n维欧氏空间E~n的有界区     

GLOBAL EXISTENCE AND EXPONENTIAL STABILITY OF SOLUTIONS TO THE QUASILINEAR THERMO-DIFFUSION EQUATIONS WITH SECOND SOUND

This article is devoted to the study of global existence and exponential stability of solutions to an initial-boundary value problem of the quasilinear thermo-diffusion equations with second sound by means of multiplicative techniques and energy method provided that the initial data are close to the equilibrium and the relaxation kernel is strongly positive definite and decays exponentially.     

GLOBAL EXISTENCE AND BLOW-UP OF SOLUTIONS FOR GENERALIZED POCHHAMMER-CHREE EQUATIONS

In this article,we study the initial boundary value problem of generalized Pochhammer-Chree equation u_(tt)-u_(xx)-u_(xxt)-u_(xxtt)=f(u) xx,x ∈Ω,t 0,u(x,0) = u0(x),u t(x,0)=u1(x),x ∈Ω,u(0,t) = u(1,t) = 0,t≥0,where Ω=(0,1).First,we obtain the existence of local W k,p solutions.Then,we prove that,if f(s) ∈ΩC k+1(R) is nondecreasing,f(0) = 0 and |f(u)|≤C1|u| u 0 f(s)ds+C2,u 0(x),u 1(x) ∈ΩW k,p(Ω) ∩ W 1,p 0(Ω),k ≥ 1,1 p ≤∞,then for any T 0 the problem admits a unique solution u(x,t) ∈ W 2,∞(0,T;W k,p(Ω) ∩ W 1,p 0(Ω)).Finally,the finite time blow-up of solutions and global W k,p solution of generalized IMBq equations are discussed.     

非线性退缩抛物型方程弱解的梯度的Holder连续性

本文我们讨论如下的非线性退缩抛物型方程：设为上述方程的弱解．在一些结构性条件下，我们得到△ｕ的Ｈ　ｌｄｅｒ连续性．     

退化的抛物方程组解的全局存在及爆破

本文讨论了退化抛物方程组初边值问题解的性质 ,通过构造上、下解 ,证明了古典解的存在唯一性 ,利用特征函数以及最大值原理 ,得出了解全局存在以及爆破的若干条件 .