广义Pochhammer-Chree方程的显式精确孤波解

首先对广义Ｐｏｃｈｈａｍｍｅｒ＿Ｃｈｒｅ方程（ＰＣ方程）ｕｔ－ｕｔｘｘ＋ｒｕｘｘｔ－（ａ１ｕ＋ａ２ｕ２＋ａ３ｕ３）ｘｘ＝０（ｒ≠０）（Ⅰ）的孤波解ｕ（ξ）建立了公式∫＋∞－∞［ｕ′（ξ）］２ｄξ＝１１２ｒｖ（Ｃ＋－Ｃ－）３［３ａ３（Ｃ＋＋Ｃ－）＋２ａ２］·由此推知：广义ＰＣ方程（Ⅰ）不可能有钟状孤波解,只可能有扭状孤波解;而广义ＰＣ方程ｕｔ－ｕｔｘｘ－（ａ１ｕ＋ａ２ｕ２＋ａ３ｕ３）ｘｘ＝０（Ⅱ）可能既有钟状孤波解又有渐近值满足３ａ３（Ｃ＋＋Ｃ－）＋２ａ２＝０的扭状孤波解·进一步求出了广义ＰＣ方程（Ⅰ）的扭状孤波解,求出了广义ＰＣ方程（Ⅱ）的钟状孤波解和渐近值满足２ａ３（Ｃ＋＋Ｃ－）＋２ａ２＝０的扭状孤波解·最后给出了广义ＰＣ方程ｕｔ－ｕｔｘｘ－（ａ１ｕ＋ａ３ｕ３＋ａ５ｕ５）ｘｘ＝０（Ⅲ）的显式孤波解     

高维空间中半线性波动方程的Sobolev指数

ＧｕｓｔａｖｏＰｏｎｃｅ与ＴｈｏｍａｓＣ．Ｓｉｄｅｒｉｓ［４］猜测对一些具有特殊非线性项的半线性波动方程，如ｕｔ－△ｕ＝ｕｋ（Ｄｕ）α（ｘ∈Ｒｎ，ｋ∈Ｚ＋，ｌ＝｜α｜２），其中Ｓｏｂｏｌｅｖ指数会在ｎ２与（ｎ２＋１）之间．文［４］中，在ｘ∈Ｒ３时，回答了这一问题．本文在ｎ３维空间中，得到了半线性波动方程ｕｔ－△ｕ＝ｕｋ（Ｄｕ）α（ｘ∈Ｒｎ，ｋ∈Ｚ＋，ｌ＝｜α｜２）的Ｓｏｂｏｌｅｖ指数为ｍａｘ｛ｎ２＋１２，（ｎ２－１）·ｌ－３ｌ－１＋２｝，此数确实在区间［ｎ２＋１２，ｎ２＋１］中．     

非线性波动方程整体解存在的一个必要条件

该文给出了非线性波动方程ｕｎ＝△ｕ＋ｆ（ｕ），（ｆ（ｕ）＝ｕ＾ｐ，ｐ〉１）的Ｃａｕｃｈｙ问题在函数空间Ｃ＾ｋ０（Ｒ＾ｎ）的原点领域有古典整体解的一个必要条件：１／２（ｕ（０）＾２Ｌ２＋ｕｔ（０）＾２Ｌ２）－∫Ｒ＾ｎ∫＾ｕ００ｆ（ｓ）ｄｓｄｘ≤０，并且证明了１〈ｐ〈＾ｎ＾２＋ｎ＋２／ｎ（ｎ－１），ｎ≠１（ｎ＝１，１〈ｐ〈＋∞）古典解与广义解有相同的生命跨度，同时给出了生命跨度的上界估计。     

双非线性抛物型方程非负解的一个性质

在Ｅ＾ｎ（０，∞）上讨论双非线性抛物型方程ａ／ａｔ（｜ｕ｜＾λ－２ｕ）－ｄｉｖ（｜△ｕ｜＾ｐ－２△ｕ）＝０在ｐ＞λ＞２的条件下，证明它的齐次Ｃａｕｃｈｙ问题非负整体解必是零解。     

具有阻尼项的非线性波动方程的初值问题

本文研究具有阻尼项的非线性波动方程的初值问题ｕｔｔ－２ｂｕｘｘｔ＋ａｕｘｘｘｘ＝β（ｕｘ＾ｎ）ｘ,;ｕ（ｘ,０）＝ψ（ｘ）,ｕｔ（ｘ,０）＝ψ（ｘ）,其中ｂ〉０,β≠０为任意实数,ｎ≥２为整 当ａ≠ｂ＾２,ψ∈Ｌ１（Ｒ）∩Ｈ＾２（Ｒ）,ψ∈Ｋ１（Ｒ）∩Ｌ３（Ｒ）时,上述问题存在唯一的整体光滑解。     

Volterra型积分微分方程非线性边值问题解的存在性和唯一性

本文利用上下解方法得到了带Ｖｏｌｔｅｒｒａ型积分算子的非线性边值问题，ｕ＾ｎ＝ｆ（ｔ，ｕ，ｕ′，Ｔｕ），ａ１ｕ（０）－ａ２ｕ′（０）＝Ａ，ｂ１ｕ（１）＋ｂ２ｕ′（１）＝Ｂ解的存在性和唯一性。     

△^2u=λu＋N＋4／N—4＋μf（x）的多解存在性

讨论了非齐次双调和方程边值问题｛△＾２ｕ＝λｕ＋Ｎ＋４／ｕＮ－４＋ｕｆ（ｘ）,ｘ∈Ωｎ＝△ｕ｜ｎ＝０,的两个正解的存在性和非存在性,这里Ω是Ｒ＾Ｎ内有界光滑区域,Ｎ〉４,λ∈Ｒ＾１,μΠ０,ｆ（ｘ）是非负连续函数。     

关于广义Benjamin—Ono方程的整体适定性

对ｋ〉ａ＋３／２的广义Ｂｅｎｊａｍｉｎ－Ｏｎｏ方程证明了当初值为小初值时相应的非线性初值问题的整体解的存在性以及唯一性，还得到了该整体解在Ｌ＾２的意义下的渐近估计。     

一类广义Sine—Gordon方程的解的存在唯一性

本文利用非线性Ｇａｌｅｒｋｉｎ方法,证明了一类广义Ｓｉｎｅ－Ｇｏｒｄｏｎ方程在Ｄｉｒｉｃｈｌｅｔ边值条件下的整体解的存在唯一性．     

一类泛连通无爪图

本文证明了如果Ｇ是３连通无爪图，且Ｇ的每个导出子图Ａ，Ａ＋都满足（ａ１，ａ２），则Ｇ是泛连通图（除了当ｕ，ｖ∈Ｖ（Ｇ），ｄ（ｕ，ｖ）＝１时，Ｇ中可能不存在（ｕ，ｖ）－ｋ路外，这里２≤ｋ≤４）．     

Exact solitary wave solutions of nonlinear wave equations

The hyperbolic function method for nonlinear wave equations is presented. In support of a computer algebra system, many exact solitary wave solutions of a class of nonlinear wave equations are obtained via the method. The method is based on the fact that the solitary wave solutions are essentially of a localized nature. Writing the solitary wave solutions of a nonlinear wave equation as the polynomials of hyperbolic functions, the nonlinear wave equation can be changed into a nonlinear system of algebraic equations. The system can be solved via Wu Elimination or Gr?bner base method. The exact solitary wave solutions of the nonlinear wave equation are obtained including many new exact solitary wave solutions.     

Exact solutions of Kolmogorov-Petrovskii-Piskunov equation using the modified simple equation method

The modified simple equation method is employed to find the exact solutions of the nonlinear Kolmogorov-Petrovskii-Piskunov （KPP） equation. When certain parameters of the equations are chosen to be special values, the solitary wave solutions are derived from the exact solutions. It is shown that the modified simple equation method provides an effective and powerful mathematical tool for solving nonlinear evolution equations in mathematical physics.     

On soliton solutions for a generalized Hirota–Satsuma coupled KdV equation

The extended homogeneous balance method is used to construct exact traveling wave solutions of a generalized Hirota–Satsuma coupled KdV equation, in which the homogeneous balance method is applied to solve the Riccati equation and the reduced nonlinear ordinary differential equation, respectively. Many exact traveling wave solutions of a generalized Hirota–Satsuma coupled KdV equation are successfully obtained, which contain soliton-like and periodic-like solutions This method is straightforward and concise, and it can also be applied to other nonlinear evolution equations.     

The Riccati Equation Method Combined with the Generalized Extended $(G''/G)$-Expansion Method for Solving the Nonlinear KPP Equation

An analytic study of the nonlinear Kolmogorov-Petrovskii-Piskunov (KPP) equation is presented in this paper. The Riccati equation method combined with the generalized extended $(G''/G)$-expansion method is an interesting approach to find more general exact solutions of the nonlinear evolution equations in mathematical physics. We obtain the traveling wave solutions involving parameters, which are expressed by the hyperbolic and trigonometric function solutions. When the parameters are taken as special values, the solitary and periodic wave solutions are given. Comparison of our new results in this paper with the well-known results are given.     

非线性波方程准确孤立波解的符号计算

该文将机械化数学方法应用于偏微分方程领域，建立了构造一类非线性发展方程孤立波解的一种统一算法，并在计算机数学系统上加以实现，推导出了一批非线性发展方程的精确孤立波解．算法的基本原理是利用非线性发展方程孤立波解的局部性特点，将孤立波表示为双曲正切函数的多项式．从而将非线性发展方程（组）的求解问题转化为非线性代数方程组的求解问题．利用吴文俊消元法在计算机代数系统上求解非线性代数方程组，最终获得非线性发展方程（组）的准确孤立波解.     

A sub-ODE method for generalized Gardner and BBM equation with nonlinear terms of any order

In this paper, a method with the aid of a sub-ODE and its solutions is used for constructing new periodic wave solutions for nonlinear Gardner equation and BBM equation with nonlinear terms of any order arising in mathematical physics. As a result, many exact traveling wave solutions are successfully obtained. The method in the paper is very direct and it can also be applied to other nonlinear evolution equations.     

一类Burgers方程的孤立波解

Burgers方程在工程上有着重要的应用,它可以用来描述湍流、车队的交通流、氏族的随机迁移、化学工程中的分离等现象,对Burgers方程求解方法的研究有着重要的现实意义.对Burgers方程求解主要是应用差分和微分两方面的方法来展开求解的,1/G展开法是近年来发展起来的求解非线性偏微分方程的一种较为有效的微分解法.采用微分方程方面的方法,利用1/G展开法对一类Burgers方程进行求解,得到了此方程的一类孤立波解和扭曲波解,同时描绘出解的图像并分析解的结构和变化趋势.     

An extended simplest equation method and its application to several forms of the fifth-order KdV equation

In this paper, an extended simplest equation method is proposed to seek exact travelling wave solutions of nonlinear evolution equations. As applications, many new exact travelling wave solutions for several forms of the fifth-order KdV equation are obtained by using our method. The forms include the Lax, Sawada-Kotera, Sawada-Kotera-Parker-Dye, Caudrey-Dodd-Gibbon, Kaup-Kupershmidt, Kaup-Kupershmidt-Parker-Dye, and the Ito forms.     

Soliton solutions of a few nonlinear wave equations

This paper carries out the integration of a few nonlinear wave equations to obtain topological as well as non-topological soliton solutions. The mathematical techniques used to obtain the soliton solutions are He’s variational iteration method, the tanh method and the ansatz method. The nonlinear wave equations that are studied are coupled mKdV equations, Drinfeld-Sokolov equation and its generalized version. Finally, some numerical simulations are given to support the analytical solutions.     

Exp-function method for Riccati equation and new exact solutions with two arbitrary functions of (2 + 1)-dimensional Konopelchenko-Dubrovsky equations

In this paper, new exact solutions with two arbitrary functions of the (2 + 1)-dimensional Konopelchenko-Dubrovsky equations are obtained by means of the Riccati equation and its generalized solitary wave solutions constructed by the Exp-function method. It is shown that the Exp-function method provides us with a straightforward and important mathematical tool for solving nonlinear evolution equations in mathematical physics.