几类非线性差分方程的对称和精确解

本文将微分方程的Lie变换群方法推广到差分方程,给出了三类非线性差分方程的不变变换,利用这种变换由差分方程的平凡解得到非平凡的单参数解族。     

奇异扰动的p-Laplace方程非负非平凡解和正解的结构

精确地刻画了某些奇异扰动的p-Laplace方程非负非平凡解和正解的结构．利用上下解方法证明，方程存在很多非负非平凡的尖峰解和正的过渡尖峰解．当参数充分小时还对每个尖峰解支集的上下界进行了估计．     

一类具有Dirichlet边界条件的振幅方程的稳定性与分岔研究（英文）

本文研究一个偏微分方程组的平凡稳态解(0,0)的稳定性和分岔的问题,所研究的方程组是一个定义在有界区域(0,L)上有着Dirichlet边界条件的振幅方程.文中区间长度L被看成是一个分岔参数.文章考虑平凡稳态解(0,0)处的渐近行为,利用扰动理论的方法,获得非平凡解分岔结果,进一步地分析了非平凡分岔解的稳定性及其渐近行为.     

RN中含Φ-Laplace算子和凹凸非线性项的拟线性椭圆型方程解的存在性

该文研究了全空间中一类含Φ-Laplace算子和凹凸非线性项的拟线性椭圆型方程非平凡解的存在性和多重性.利用Nehari流形方法和纤维映射等技巧,在参数较小的情况下,得到方程至少有两个非平凡解,其中一个是基态解.     

一类分数阶脉冲微分方程Dirichlet边值问题非平凡解的存在性

研究了一类带有脉冲的分数阶微分方程Dirichlet边值问题非平凡解的存在性.通过利用变分法和Morse理论证明了此分数阶脉冲微分方程至少存在一个非平凡解.     

一类含多奇性项的Grushin型算子方程解的渐近性质

本文研究了一类含多个奇性项的Grushin型算子方程非平凡解的渐近性质问题.当方程的非线性项满足临界指数增长条件时,利用Moser迭代方法和分析技巧,获得了方程的非平凡解在奇点处的渐近性质,推广了Laplace算子的相关结果.     

一类临界拟线性椭圆型方程组解的存在性

本文讨论了一类临界拟线性椭圆型方程组解的存在性问题.利用LionsPL提出的第二集中紧性原理和山路引理,证明了该方程组在超线性扰动情形下非平凡解的存在性.此外,利用极值原理,也得到了该方程组在次线性扰动情形存在非平凡解.     

2n阶两点边值问题的多重非平凡解

本文主要研究2n阶两点边值问题的多重非平凡解的存在性．利用不动点指数理论和Leray-schauder度,在一般的非线性条件下,证明了2n阶两点边值问题至少有六个非平凡解的存在性．而且,如果非线性项是奇函数,则至少有八个非平凡解的存在．     

离散共振问题的非平凡解

研究了一类二阶非线性差分方程两点边值问题非平凡解的存在性.假设该问题在无穷远点及零点处均是共振的,利用变分方法,同时考虑正、负能量泛函的临界点,在一定的假设条件下,通过临界群的计算,证明了该问题至少存在一个非平凡解.     

带有奇异项的临界增长p-Laplace方程的非平凡解

本文研究了一种带有奇异项的临界增长p-Laplace方程在N维空间中的有界集上非平凡解的问题,利用山路引理和集中紧性原理,得出方程在非线性项满足一定条件下有非平凡解的结果.     

A series of abundant exact travelling wave solutions for a modified generalized Vakhnenko equation using auxiliary equation method

In this paper, a series of abundant exact travelling wave solutions is established for a modified generalized Vakhnenko equation by using auxiliary equation method. These solutions can be expressed by Jacobi elliptic function. When Jacobi elliptic functions modulus m→1 or 0, the travelling wave solutions degenerate to four types of solutions, namely, the soliton solutions, the hyperbolic function solutions, the trigonometric function solutions, constant solutions.     

On Producing Multiple Solutions Using Repeated Trials

The number of trials that is required by an algorithm to produce a given fraction of the problem solutions with a specified level of confidence is analyzed. The analysis indicates that the number of trials required to find a large fraction of the solutions rapidly decreases as the number of solutions obtained on each trial by an algorithm increases. In applications where multiple solutions are sought, this decrease in the number of trials could potentially offset the additional computational cost of algorithms that produce multiple solutions on a single trial. The analysis framework presented is used to compare the efficiency of a homotopy algorithm to that of a Newton method by measuring both the number of trials and the number of calculations required to obtain a specified fraction of the solutions.     

Group-invariant solutions, non-group-invariant solutions and conservation laws of Qiao equation

This paper considers a completely integrable nonlinear wave equation which is called Qiao equation. The equation is reduced via Lie symmetry analysis. Two classes of new exact group-invariant solutions are obtained by solving the reduced equations. Specially, a novel technique is proposed for constructing group-invariant solutions and non-group-invariant solutions based on travelling wave solutions. The obtained exact solutions include a set of traveling wave-like solutions with variable amplitude, variable velocity or both. Nonlocal conservation laws of Qiao equation are also obtained with the corresponding infinitesimal generators.     

具有多重解的非线性奇摄动问题

利用边界层法,研究了一类具有多重解的非线性奇摄动问题．在适当的假设下,通过给出外部解展开式系数及其对应边界条件的一般表达式,根据退化问题的边值作为某方程的根的重数,得到了此问题不同形式的渐近解．特别地,当这种根的重数为偶数时,问题具有二重解．另外,将相关结果应用于化学反应器理论,并通过对具有多重解的例子的渐近解和精确解的数值模拟说明如此构造的渐近解具有较高的精度．     

Traveling wave solutions in a diffusive system with two preys and one predator

This paper is concerned with the traveling wave solutions in a diffusive system with two preys and one predator. By constructing upper and lower solutions, the existence of nontrivial traveling wave solutions is established. The asymptotic behavior of traveling wave solutions is also confirmed by combining the asymptotic spreading with the contracting rectangles. Applying the theory of asymptotic spreading, the nonexistence of traveling wave solutions is proved.     

扩展的(G'/G)展开法求量子Zakharov-Kuznetsov方程的精确解

为得到量子Zakharov-Kuznetsov方程的一些新精确解,借助行波解的思想,结合齐次平衡原理和一类非线性常微分方程解的结构,利用扩展的(G’/G)展开方法,研究了其相应的更加丰富的精确解表达形式.新精确解的表达式主要由双曲函数、三角函数和有理数函数构成,出现了某些怪波解的情形.通过对比不同情况下解的形式,利用Matlab软件给出数值模拟图形,并根据图形的特点分析了一些怪波现象形成的机理.     

Brusselator方程解的存在性和稳定性

本文研究了一种Brusselator方程的。用不变区域证明了解的全局存在性，并通过构造上下解给出了非常数定态解渐进稳定的条件。最后推出吸引域。     

非线性演化方程的孤立波解

用齐次平衡原则和辅助微分方程方法得到了6个重要的n次非线性演化方程的孤立波解.辅助微分方程方法的主要思想是借助简单的可解微分方程的解去构造复杂的非线性演化方程的行进波解.这里简单的可解微分方程称为辅助微分方程.本文使用的辅助方程有双曲正割幂型解或双曲正切幂型解.     

A second Wronskian formulation of the Boussinesq equation

A Wronskian formulation leading to rational solutions is presented for the Boussinesq equation. It involves third-order linear partial differential equations, whose representative systems are systematically solved. The resulting solutions formulas provide a direct but powerful approach for constructing rational solutions, positon solutions and complexiton solutions to the Boussinesq equation. Various examples of exact solutions of those three kinds are computed. The newly presented Wronskian formulation is different from the one previously presented by Li et al., which does not yield rational solutions.     

A NOTE ON QUASI-P RADICAL OF ASSOCIATIVE RINGS

Let P be an arbitrary property of rings and homomorphlcally closed. For an arbitraryring A we construct quasi-P radical O.P(A) with transfinite induction, and give another character-ization of quasi-P radical;