OPTIMAL CONVERGENCE RATE OF THE LANDAU EQUATION WITH FRICTIONAL FORCE

The Cauchy problem of the Landau equation with frictional force is investigated.Based on Fourier analysis and nonlinear energy estimates,the optimal convergence rate to the steady state is obtained under some conditions on initial data.     

THE NON-CUTOFF BOLTZMANN EQUATION WITH POTENTIAL FORCE IN THE WHOLE SPACE

This paper is concerned with the non-cutoff Boltzmann equation for full-range interactions with potential force in the whole space. We establish the global existence and optimal temporal convergence rates of classical solutions to the Cauchy problem when initial data is a small perturbation of the stationary solution. The analysis is based on the timeweighted energy method building also upon the recent studies of the non-cutoff Boltzmann equation in [1–3, 15] and the non-cutoff Vlasov-Poisson-Boltzmann system [6].     

GEVREY REGULARITY FOR SOLUTION OF THE SPATIALLY HOMOGENEOUS LANDAU EQUATION

In this paper, we study the Gevrey class regularity for solutions of the spatially homogeneous Landau equations in the hard potential case and the Maxwellian molecules case.     

Helmholtz方程周期Green函数及其偏导数截断误差收敛阶的分析

在应用边界元方法求解Helmholtz方程周期边值问题时,需要构造以周期Green函数或其偏导数为核函数的积分算子形式的解.由于Helmholtz方程的周期Green函数G~P是一个函数项级数,该级数的通项是Hankel函数,在数值求解中,需要对其进行截断,从而很有必要研究其截断误差.本文根据Hankel函数在变量趋于无穷大时的渐近展开式,并结合Abel不等式,证明了G~P及其一阶偏导和二阶混合偏导一致收敛,且其截断误差收敛阶均为O(1/p~(1/2)).最后,通过数值实验验证了理论证明的正确性.本文的证明方法也可被用于证明其它一些方程周期Green函数的收敛性问题.     

半参数回归模型非参数分量L1模估计的最优收敛速度

对半参数回归模型，采用分段多项式逼近非参数函数，构造了参数与非参数分量Ｌ１模糊估计，并获得了非参数分量Ｌ１模估计的最优估计收敛速度为Ｏｐ（ｎ＾－ｍ＋ｒ／［２（ｍ＋ｒ）＋１］）。     

EXISTENCE OF INFINITE ENERGY SOLUTION TO THE INELASTIC BOLTZMANN EQUATION WITH EXTERNAL FORCE

In this paper,the Cauchy problem for the inelastic Boltzmann equation with external force is considered in the case of initial data with infinite energy.More precisely,under the assumptions on the bicharacteristic generated by external force,we prove the global existence of solution for small initial data compared to the local Maxwellian exp{ p|x v|2},which has infinite mass and energy.     

关于四维Liouville方程解的注记

本文求得了四维Euclid空间中liouville方程的依赖于两个任意复Fueter解析函数的一般解,并讨论了一般情形.     

一类矩阵方程的正交对称解及其最佳逼近

1引言设Rn×m表示所有n×m实矩阵集合,I表示单位矩阵,AT表示矩阵A的转置矩阵, ORn×n={P|PTP=I)表示列正交矩阵集,SORn×n={P|PT=P,P2=I}表示对称正交对称矩阵集．如无特别说明,本文中的矩阵P均指这类对称正交对称矩阵．在Rn×m上定义内积为     

矩阵方程AX＝B的中心对称解及其最佳逼近

基于一种新的思路,本文将一类约束矩阵方程问题化为无约束矩阵方程问题,从而轻易地获得了简洁且满意的结果.     

Ginzburg-Landau方程动力性态的Fourier谱逼近

0　引言和符号立方Schrodinger方程或更一般的形式Ginzburg-Landau方程出现在许多物理和化学问题中.例如在非线性光学的细束流中有方程2ikux+2⊥u+n2n0k2|u|2u=0对于二维流,有方程n2n0k2|u|2u=-2kiut-uxx-uyy还有等离子体的Langmuir波;一维单色波的自调制;二维定态平面波的自聚集;在非相对论下超导电子对在电磁场中运动等均可用非线性Schrodinger方程和Ginzburg-Landau方程来描述[1-4].另外,反应扩散方程描述的化学反应方程的研究中也出现Ginzburg-Landau方程,如相对于稳态浓度c*的扰动浓度c-c*就满足Ginzburg-Landau方程[5,6].由…     

关于抛物型方程离散流量的收敛性

关于用差分方法求解具有间断系数的二阶抛型方程的问题, Ａ．Ｈ． ＴＮＸＯＨＯＢ与 Ａ．Ａ．Ｃａｍａｐｃ　从１９６１年山开始曾经作过详尽的研究,他们的结果都总结在专著［２］中,有关的文献也可以在该书中找到．他们指出在系数间断点处附近的网格点上格式的截断误差为Ｏ（１）,但差分格式的解在极大意义下收敛于原微分方程的连续解．他们在构造差分格式,并论证其收敛性时,充分利用了原微分方程中流连续的性质,但是却没有讨论差分格式中的离散流量的收敛性．８０年代 Ｔ．Ａ． Ｍａｎｔｅｎｆｆｅｌ, Ａ．Ｂ． Ｗｈｉｔｅ, Ｊｒ…     

ON THE CONVERGENCE OF KING-WERNER ITERATION METHOD IN BANACH SPACE ON THE CONVERGENCE OF KING-WERNER ITERATION METHOD IN BANACH SPACE

1. IntroductionLetf(x) = 0 (1.1)where j: X - Y is a norilineax operator which maps Banach space X into Baaedspace Y. The well-known iteration methods for solving (1.1) are the Nixon methodaam very ldnds of its improvement methods. One of them is the so called King-Wernerm6thod denned bykw(p, x03 yo):which is established by King in [7], Werner in [12] in d~nt formulas, respectively.It is interesting that the method (1.2) is of order 1 fi with the same functioncompotatinn coSt and twO ti…     

ON THE RATES OF CONVERGENCE IN THE CENTRAL LIMIT THEOREM FOR TWO－PARAMETER MARTINGALE DIFFERENCES

ＯＮＴＨＥＲＡＴＥＳＯＦＣＯＮＶＥＲＧＥＮＣＥＩＮＴＨＥＣＥＮＴＲＡＬＬＩＭＩＴＴＨＥＯＲＥＭＦＯＲＴＷＯ－ＰＡＲＡＭＥＴＥＲＭＡＲＴＩＮＧＡＬＥＤＩＦＦＥＲＥＮＣＥＳ￥（龙红卫）ＬｏｎｇＨｏｎｇｗｅｉ（ＩｎｓｔｉｔｕｔｅｏｆＭａｔｈｅｍａｔｉｃａｌ...     

伽玛分布族参数的经验Bayes双边检验的收敛速度:NA样本情形

本文研究了NA样本情形下,伽玛分布族形状参数的经验Bayes(EB)双边检验问题.利用概率密度函数的核估计,构造了参数的经验Bayes检验函数,并在适当的条件下,证明了所提出的经验Bayes检验函数的渐近取优(a.o.)性,获得了其收敛速度.     

OPTIMAL DECAY RATE OF THE COMPRESSIBLE QUANTUM NAVIER-STOKES EQUATIONS

For quantum fluids governed by the compressible quantum Navier-Stokes equations in $\Bbb R^3$ with viscosity and heat conduction, we prove the optimal $L^p-L^q$ decay rates for the classical solutions near constant states. The proof is based on the detailed linearized decay estimates by Fourier analysis of the operators, which is drastically different from the case when quantum effects are absent.     

一类广义Sylvester方程的反对称最小二乘解及其最佳逼近

本文利用矩阵的奇异值分解(SVD),给出了广义Sylvester矩阵方程AX YA=C反对称解存在的充分必要条件,导出了其反对称解和反对称最小二乘解的表达式,同时在解集合中得到了对给定矩阵的最佳逼近解.     

DECAY ESTIMATES OF PLANAR STATIONARY WAVES FOR DAMED WAVE EQUATIONS WITH NONLINEAR CONVECTION IN MULTI-DIMENSIONAL HALF SPACE

This paper is concerned with the initial-boundary value problem for damped wave equations with a nonlinear convection term in the multi-dimensional half space R n + : u tt u + u t + divf (u) = 0, t > 0, x = (x 1 , x ′ ) ∈ R n + := R + × R n 1 , u(0, x) = u 0 (x) → u + , as x 1 → + ∞ , u t (0, x) = u 1 (x), u(t, 0, x ′ ) = u b , x ′ = (x 2 , x 3 , ··· , x n ) ∈ R n 1 . (I) For the non-degenerate case f ′ 1 (u + ) < 0, it was shown in [10] that the above initialboundary value problem (I) admits a unique global solution u(t, x) which converges to the corresponding planar stationary wave φ(x 1 ) uniformly in x 1 ∈ R + as time tends to infinity provided that the initial perturbation and/or the strength of the stationary wave are sufficiently small. And in [10] Ueda, Nakamura, and Kawashima proved the algebraic decay estimates of the tangential derivatives of the solution u(t, x) for t → + ∞ by using the space-time weighted energy method initiated by Kawashima and Matsumura [5] and improved by Nishihkawa [7]. Moreover, by using the same weighted energy method, an additional algebraic convergence rate in the normal direction was obtained by assuming that the initial perturbation decays algebraically. We note, however, that the analysis in [10] relies heavily on the assumption that f ′ (u) < 0. The main purpose of this paper isdevoted to discussing the case of f ′ 1 (u b ) ≥ 0 and we show that similar results still hold for such a case. Our analysis is based on some delicate energy estimates.     

具有点态控制约束热方程的时间与范数最优控制问题的等价性

本文研究了具有点态控制热方程的等价性问题.利用变分法分析时间最优控制的唯一性,能控性以及范数最优控制的特征,获得了具有点态控制约束热方程的时间与范数最优控制问题之间的等价性,推广了现有文献的结果.     

截断和大数律的收敛速度

本文研究了截断和大数律的收敛速度，证明了截断和（固定）完全收敛性定理以及大数律收敛速度的几个等价条件，从而推广了独立和的结果。     

波动方程单位分解有限元法及收敛性分析

<正>1引言与问题的提出自黄云清和许进超提出基于单位分解技术的重叠型非匹配网格有限元方法以来,这类方法日益引起人们极大的兴趣.这篇文章将这类有限元方法运用到波动方程当中,分别研究了重叠型非匹配网格波动方程半离散和全离散有限元方法,给出了有限元解及其梯度的误差估计.下面先给出模型问题的简单介绍.