POSITIVENESS THEOREMS OF SOLUTIONS FOR SEVERAL DIFFERENTIAL INEQUALITIES AND THEIR APPLICATIONS

IIntroductlonMny mathematical models rom physics,chemistry biology,economics etc．are so calledre。ilo。dlAslon srstems．ljtlstence of tr。ling w。front solutions(TWFSs)for these sys－terns rdects Int。aCtions among components ofsystems and TTSs have their own physicalme。lug(see【l])．The upper。d ic。r solutions method Is often used to pro、the。lstenceofTWFSs for certain concrete models．Difficulties consist ofconstrudlug concrete upper andlower solutions and provingtheboundedness and…     

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.     

互助-竞争型扩散反应方程解的渐近性质

含有n个物种的生态问题中,要研究如下形式的定解问题:其中ΩR~n是开区域,x=(x_1,…,x_n),a_i<0(i=1,…,m).[1]中讨论了m=2的竞争情形,即a_(ij)<0(i≠j,i,j=1,2)。[2]中讨论了m=3且是第二边     

《现代痕量元素分析方法》

书中较详尽叙述了现代常用的痕量元素分析测定方法,系统地概括了现代痕量元素分析技术的动态及研究成果,总结、介绍了每种分析方法的基础理论知识和具体应用。该书有以下几个特点:     

化学类本科生专业课程双语教学的一些反思与心得

探讨总结了在大学化学高年级双语课程--生物传感及表面分析课程讲授过程中教材选取、教学方式多样化、评估体系优化等方面的一些得与失,结合笔者的切身体会以及学生的反馈,力求对高校本科生双语教学做一些添砖加瓦的尝试。     

The existence, uniqueness and stability of positive periodic solution for periodic reaction-diffusion system

1. IntroductionLet fi e RN be a bounded open domain with smooth boundary afl, and for eachi E {1, 2,', m}, let Li be a second order differelltial operator defined byand Bi be a boundary operator given bywhere % denotes the outward normal derivative of m on an.We consider the following boundary value problem of the reaction-diffusion system withtime delaywhere i = 1, 2,'. I m) mr = "i(x, t -- r), r 2 0 is a constant. If r ~ 0, it means that system(I) does not include the terms of time lag…     

ON MULTIPLE POSITIVE PERIODIC SOLUTIONS FOR PARABOLIC SYSTEM

A class of semilinear ω-periodic parabolic systems is studied. First, by combining the degree theory with upper-lower solution method, the general principle which is used for proving that the system has at least two positive ω-periodic solutions is established. Then some applications are given.