一个反应扩散方程的门槛结果

本文讨论反应扩散方程Ｃａｕｃｈｙ问题解的整体存在性，渐近性质和Ｂｌｏｗｕｐ问题．其中或者１＜ｑ＜ｐ＜＋∞，ｎ＝２．得到门槛结果．     

给定主曲率函数的曲面存在性定理

本文给出了Ｒ３，Ｒ２，１内给定主曲率函数的一类特殊曲面的局部、整体存在性定理的一个充要条件．     

方程u_(tt)=u_(xxt) f(u_x)_x初边值问题的差分法

１．引言方程是在国内外引起广泛关注的一类重要的非线性发展方程．文［１］在函数ｆ（ｓ）满足局部 Ｌｉｐ－ｓｃｈｉｔｚ条件及单调性条件（ｆ（ｓ２）－ｆ（ｓ１））（ｓ２－ｓ１）＞ ０的假设下得到了（１．１）初边值问题整体弱解的存在与唯一性;文［２］用 Ｇａｌｅｒｋｉｎ方法,研究了（１．１）的初边值问题,周期边值问题和初值问题,并在函数ｆ’（ｓ）下方有界的假设下得到了整体强解的存在与唯一性． 本文在有限区域 ＱＴ＝［０,１］×［０,Ｔ］（Ｔ＞ ０）上讨论方程（１．１）带有初值条件和边值条件（ｕ（ｘ,ｔ）为未知…     

具有特殊扩散过程的反应扩散方程

本文考虑如下具有特殊扩散系数的化学反应扩散方程的整体解存在性、渐近性和局部解有限时间爆破,这里Ω是ＲＮ（Ｎ≥３）中的光滑有界区域,０∈Ω,１＜Ｐ＜Ｎ＋２／Ｎ－２．     

黎曼曲面到S~2的非均匀Landau-Lifshitz方程组

本文主要考虑从黎曼曲面到Ｓ２的非均匀Ｌａｎｄａｕ－Ｌｉｆｓｈｉｔｚ方程组的解的存在性．证明了对于适当初始值,方程是存在唯一的,除有限个点外处处正则的整体解,并且该解在每一奇点处爆破成一个光滑的调和映射 还讨论了方程组在ＩＲ２上定常解的不存在性．     

巧解一次方程组

解一次方程组的思想是消元，消元后转化为一元一次方程．但还要注意仔细观察，认真分析题目的特征、巧妙、灵活地运用消元法来解题．例１　解方程组（１）２ｘ＋ｙ－ｚ＝２，ｘ＋２ｙ＋３ｚ＝１３，－３ｘ＋ｙ－２ｚ＝－１１；　①②③（２）ｘ＋２ｙ－３ｚ＝－４，４ｘ＋８ｙ＋９ｚ＝５，２ｘ＋６ｙ－９ｚ＝－１５．　①②③分析　上面两题若逐步消元，都比较麻烦．仔细观察，发现方程组（１）三式相加可得ｙ；而方程组（２）呢，可先整体消元求出ｘ和ｚ，于是得妙解．（１）解　由①＋②＋③得４ｙ＝４，即ｙ＝１．把ｙ＝１代入①、②，得…     

一类R^2上奇异非线性双调和方程正整解

以Ｓｃｈａｕｄｅｒ Ｔｙｃｈｏｎｏｆｆ不动点定理为工具,建立了一类犚２ 上奇异非线性双调和方程正 的径向对称整体解的存在定理,并给出了解的有关性质．     

二维带形无界区域中Navier－Stokes方程整体吸引子及其维数估计

该文讨论二维无界带形区域中Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程其中Ω＝（０，ｄ）×Ｒ，ｄ＞０为一常数，ｕ与ｐ为未知量，其中ｕ＝（ｕ１，ｕ２）为速度场，ｐ表示压力．我们证明了当ｕ０∈Ｈ，ｆ∈Ｖ且ｆ［ｌｏｇ（ｅ＋｜ｘ｜２）］１／２∈Ｌ２（Ω）时，问题（Ｉ）在Ｈ中存在整体吸引子Ａ，它是的一个子集．对Ａ的Ｈａｕｓｄｏｒｆｆ维数与Ｆｒａｃｔａｌ维数我们也给出了估计．     

一类非线性FDE整体解的存在性及全局吸引性

本文研究了ＦＤＥ 整体解的存在性及其零解的全局吸引性，所得结果应用于具有时滞的单种群人口模型 则改进了文［１，２］中的相应结论．     

非线性抛物型积分微分方程有限元方法的插值后处理技术

本文以两类非线性抛物型积分微分方程为例，首次尝试将插值后处理思想［１］应用到非线性发展型方程上，获得了半离散和全离散有限元解，经插值后处理之后在Ｌ∞（Ｈ１）；Ｌ∞（Ｌ２）模意义下，整体超收敛１阶的高精度，并且计算量没有因此而增加．本文引进并证明较文［２］更广泛的一类椭圆Ｈ１－Ｖｏｌｔｅｒｒａ投影的Ｈ１；Ｌ２，Ｈ－１模最优估计．本文的分析方法可在各类发展型微分及积分微分方程上面通用．     

Five-wave classical scattering matrix and integrable equations

We study the five-wave classical scattering matrix for nonlinear and dispersive Hamiltonian equations with a nonlinearity of the type u?u/?x. Our aim is to find the most general nontrivial form of the dispersion relation ω(k) for which the five-wave interaction scattering matrix is identically zero on the resonance manifold. As could be expected, the matrix in one dimension is zero for the Korteweg-de Vries equation, the Benjamin-Ono equation, and the intermediate long-wave equation. In two dimensions, we find a new equation that satisfies our requirement.     

On the stochastic Benjamin-Ono equation

We discuss the Cauchy problem for the stochastic Benjamin-Ono equation in the function class Hs(R), s>3/2. When there is a zero-order dissipation, we also establish the existence of an invariant measure with support in H²(R). Many authors have discussed the Cauchy problem for the deterministic Benjamin-Ono equation. But our results are new for the stochastic Benjamin-Ono equation. Our goal is to extend known results for the deterministic equation to the stochastic equation.     

The regularized Benjamin-Ono and BBM equations: Well-posedness and nonlinear stability

Nonlinear stability of nonlinear periodic solutions of the regularized Benjamin-Ono equation and the Benjamin-Bona-Mahony equation with respect to perturbations of the same wavelength is analytically studied. These perturbations are shown to be stable. We also develop a global well-posedness theory for the regularized Benjamin-Ono equation in the periodic and in the line setting. In particular, we show that the Cauchy problem (in both periodic and nonperiodic case) cannot be solved by an iteration scheme based on the Duhamel formula for negative Sobolev indices.     

Error Estimate of the Fourier Collocation Method for the Benjamin-Ono Equation

In this paper, the Fourier collocation method for solving the generalized Benjamin-Ono equation with periodic boundary conditions is analyzed. Stability of the semi-discrete scheme is proved and error estimate in H1/2-norm is obtained.     

Weak Continuity of the Flow Map for the Benjamin-Ono Equation on the Line

In this paper we show that the flow map of the Benjamin-Ono equation on the line is weakly continuous in L ²(?), using “local smoothing” estimates. L ²(?) is believed to be a borderline space for the local well-posedness theory of this equation. In the periodic case, Molinet (Math. Ann. 337, 353–383, 2007) has recently proved that the flow map of the Benjamin-Ono equation is not weakly continuous in $L^{2}(\mathbb{T})In this paper we show that the flow map of the Benjamin-Ono equation on the line is weakly continuous in L ²(ℝ), using “local smoothing” estimates. L ²(ℝ) is believed to be a borderline space for the local well-posedness theory of this equation. In the periodic case, Molinet (Math. Ann. 337, 353–383, 2007) has recently proved that the flow map of the Benjamin-Ono equation is not weakly continuous in L²(\mathbbT)L^{2}(\mathbb{T}). Our results are in line with previous work on the cubic nonlinear Schr?dinger equation, where Goubet and Molinet (Nonlinear Anal. 71, 317–320, 2009) showed weak continuity in L ²(ℝ) and Molinet (Am. J. Math. 130, 635–683, 2008) showed lack of weak continuity in L²(\mathbbT)L^{2}(\mathbb{T}).     

Decay Properties of Global Solutions for Benjamin-Ono Equation of High Order

The decay properties of global solutions for the Benjamin-Ono equation of high order are obtained as |x| → ∞. An Iorio's type result is derived for this equation.     

Estimates of low Sobolev norms of solutions for some nonlinear evolution equations

In this work we obtain results on the estimates of low Sobolev norms for solutions of some nonlinear evolution equations, in particular we apply our method for the complex modified Korteweg-de Vries type equation and Benjamin-Ono equation.     

On vortex perturbations in a free-interacting boundary layer

Large-scale structures with an inviscid, non-linear subdomain (deck) on the bottom of a boundary layer in the case of subsonic and transonic free stream velocities are considered. A class of locally inviscid perturbations with an internal line of discontinuity of the tangential velocity, which leads to the appearance of a free term on the right-hand side of the Benjamin-Ono equations, is investigated. The shape of the above-mentioned line is sought and it is determined from the solution of a system of one-dimensional non-stationary equations in which, apart from the Benjamin-Ono equation, a kinematic condition and an equation for the inviscid deck close to the wall also occur. An example of a periodic, non-linear solution is constructed and amplitude constraints which ensure its realization are formulated.     

The Cauchy problem for the stochastic generalized Benjamin-Ono equation

The current paper is devoted to the Cauchy problem for the stochastic generalized Benjamin-Ono equation.By establishing the bilinear and trilinear estimates in some Bourgain spaces,we prove that the Cauchy problem for the stochastic generalized Benjamin-Ono equation is locally well-posed for the initial data u_0(x,w)∈L~2(Ω;H~s(R)) which is F_0-measurable with s≥1/2-α/4 and Φ∈L_2~(0,s).In particular,when α=1,we prove that it is globally well-posed for the initial data u_0(x,w)∈L~2(Ω;H~1(R)) which is F_0-measurable and Φ∈L_2~(0,1).The key ingredients that we use in this paper are trilinear estimates,the Ito formula and the Burkholder-Davis-Gundy(BDG) inequality as well as the stopping time technique.     

Large Amplitude Solitary Waves in Unbounded Stratified Fluids

Solitary waves of arbitrary amplitude are found to exist for a class of unbounded stratified flow configurations. In special cases the solutions are similar to those obtained from the Benjamin-Ono equation.