一类退化-奇异抛物型方程的行波解Ⅱ

多孔介质动力学及生物群体动力学方程引起愈来愈多的人的注意,退化-奇异抛物型方程(u~m/m)_t=(u~k)_(xx)+u~nf(u)的行波解也成为人们关心的课题之一.Aronson对 m=k=1,u~nf(u)∈C~1[0,1]讨论了单调行波解的存在性与正则性,Hosono 对m=1,k≥2,n=0,f∈C~2[0,1],f(0)=f(1)=0,f′(0)<0,f″(0)(?)0,f′(1)<0且在(0,α)内 f(u)<0;在(α,1)内 f(u)>0,讨论了单调行波解的存在性与稳定     

退化抛物型方程的行波解(Ⅰ)

本文讨论退化抛物型方程(u~m/m)_t=u_(xx)=u~nf(u)的波前解的存在性与正则性。其中m,n>0,f(u)与(u-a)(1-u)有类似性质。证明了正则性完全依赖于m,n的值。     

一类退化非线性抛物型方程整体解的衰减估计

J.L.L ions用紧致性方法证明了一类退化非线性抛物型方程初边值问题整体解的存在唯一性,但解的衰减性很少有人考虑.应用M.N akao建立的差分不等式研究了整体解的衰减估计.     

一类双退化非线性抛物型方程

In this paper we study the decay estimate of global solutions to the initialboundary value problem for double degenerate nonlinear parabolic equation by using a difference inequality.     

一类奇异抛物方程淬火解的数值分析

本文利用有限差分方法研究一类带奇异Neumann边界条件和奇异反应项的半线性抛物方程数值解的渐近行为.在初值满足一定假设的条件下,证明了数值解淬火速率与连续解淬火速率的一致性,数值淬火时间收敛于连续淬火时间,并通过数值实验验证了理论分析.     

一类奇异抛物型方程弱解的连续性

本文引入了空间 V_m~(1、0)(Ω_T)并讨论了它的嵌入定理,由此得到了一类奇异抛物型方程的本性有界弱解直到边界的连续性.增长阶是一般的正数 m(≥2).这样,就将[4]关于 V_2~(1,0)(Ω_T)的结果以及[3]关于 m=2时的正则性结果推广到了一般的情形.     

一类奇异抛物型方程弱解的连续性

本文引入了空间V_m~(1、0)(Ω_T)并讨论了它的嵌入定理,由此得到了一类奇异抛物型方程的本性有界弱解直到边界的连续性。增长阶是一般的正数m(≥2)。这样,就将[4]关于V_2~(1、0)(Ω_(?))的结果以及[3]关于m=2时的正则性结果推广到了一般的情形。     

一类退化抛物方程的边值问题

In this paper, we study the boundary value problem (BVP) for a degenerate parabolic equation. By introducing a proper notion of weak solutions, we prove the uniqueness and existence of weak solutions of the problem. The localization of weak solutions is also discussed, which plays a key role in the proof of the uniqueness.     

一类双重退化抛物方程局部解的存在性

This paper deals with a class of doubly degenerate parabolic equations, including as particular cases the porous medium equation and the degenerate p- Laplace equation(p＞2) u_t-div(b(x,t,u)|▽u|~(p-2)▽u)=f(x,u,t). The initial-boundary value problem in a bounded domain of R~N is considered under mixed boundary conditions.The existence of local-in-time weak solutions is obtained.     

一类反应扩散方程的行波解

1　引　　言由于反应扩散方程涉及的大量问题来自物理学、化学、生物学和人口动力学中众多的数学模型,因而有广阔的实际背景.其行波解引起了人们的兴趣,行波解是某个常微分方程的解,对某些传播速度,利用几何方法可以建立其解的存在性(见[1][2][3]).在文[4]中J.Canosa讨论了Fisher方程ut=2u2x+u(1-u)(1)行波解的存在性、逼近解和误差估计.所谓方程(1)的行波解是指形为u(x,t)=u(x-ct)=u(z)的解.众所周知,行波解u(x,t)=u(x-ct)=u(z)是方程(1)的行波解的充要条件是d2udz2+cdudz+u(1-u)=0(2)若u(z)是单调有界且不恒为常数,则u(z)叫做(1)的波前…     

WEAK TRAVELLING WAVE FRONT SOLUTIONS OF GENERALIZED DIFFUSION EQUATIONS WITH REACTION

The author demonstrate that the two-point boundary value problem {p′(s)=f′(s)-λp^β(s)for s∈(0,1);β∈(0,1),p(0)=p(1)=0,p(s)&gt;0 if s∈(0,1),has a solution(λ^-，p^-（s）),where |λ^-| is the smallest parameter,under the minimal stringent restrictions on f(s), by applying the shooting and regularization methods. In a classic paper, Kohmogorov et.al.studied in 1937 a problem which can be converted into a special case of the above problem. The author also use the solution(λ^-,p^-(s)) to construct a weak travelling wave front solution u(x,t)=y(ξ),ξ=x-Ct,C=λ^-N/(N+1),of the generalized diffusion equation with reaction δ/δx（k（u）|δu/δx|^n-1 δu/δx)-δu/δt=g（u），where N&gt;0,k(s)&gt;0 a.e.on(0,1),and f(a):=n+1/N∫0ag(t)k^1/N(t)dt is absolutely continuous ou[0,1],while y(ξ) is increasing and absolutely continuous on (-∞,+∞) and (k(y(ξ))|y′(ξ)|^N)′=g(y(ξ))-Cy′(ξ)a.e.on(-∞，+∞）,y(-∞)=0,y(+∞)=1.     

NEW EXACT TRAVELLING WAVE SOLUTIONS OF NONLINEAR WAVE EQUATIONS USING THE DYNAMICAL SYSTEM METHOD

By the method of dynamical system,we construct the exact travelling wave solutions of a new Hamiltonian amplitude equation and the Ostrovsky equation.Based on this method,the new exact travelling wave solutions of the new Hamiltonian amplitude equation and the Ostrovsky equation,such as solitary wave solutions,kink and anti-kink wave solutions and periodic travelling wave solutions,are obtained,respectively.     

LARGE TIME BEHAVIOR OF SOLUTIONS TO SOME DEGENERATE PARABOLIC EQUATIONS

The purpose of this paper is to study the limit in L ¹(Ω), as t → ∞, of solutions of initial-boundary-value problems of the form u_t ? Δw = 0 and u ∈ β(w) in a bounded domain Ω with general boundary conditions ?w/?η + γ(w) ? 0. We prove that a solution stabilizes by converging as t → ∞ to a solution of the associated stationary problem. On the other hand, since in general these solutions are not unique, we characterize the true value of the limit and comment the results on the related concrete situations like the Stefan problem and the filtration equation.     

一类非线性抛物方程的L∞估计

本文给出了一种统一的方法来得到一类非线性抛物方程的有界解的先验的L∞估计.这类方程的基本类型是其中v=v(x,t)是一个满足某些条件的非负可测权函数.由此可以去掉文[5]中的一个本质性的条件p≥2.     

二阶完全非线性抛物型方程的周期解

证明了二阶完全非线性抛物型方程周期粘性解的存在唯一性，在标准假设下解决了非线性抛物型方程古典周期解的存在唯一性问题。     

抛物型方程广义解的Phragmen-Lindelf原理

设Ω为Ｅｎ中的无界，连通区域．在Ω×（０，∞）上考虑抛物型方程：设，Ｂ满足结构条件：设存在和，使对任何ρ０＞ρ１＞０：设ｕ是方程的广义解，并且如果ｕ在Ω×（０，Ｔ）为有界，那么ｕ＋≤０．     

K(n,2n,-n)方程行波解的分支

本文研究了K(n,2n,-n)方程行波解与参数a,b,c,g,n等的关系.利用动力系统分支理论,得到了孤立波、扭结和反扭结波解,以及不可数无穷多光滑周期波解的存在性.本文推广了文献[1]中的结果.