特征函数的性质

得到了特征函数、条件特征函数的一致可微性和条件特征函数的反演公式.     

随机变量和的特征函数的性质与应用

运用随机变量和的特征函数定义研究了随机变量和的特征函数在原点处二阶导数与协方差矩阵的关系,并给了一个简单的应用.     

非线性Schrodinger方程初边值问题解的Blow-up

利用Laplace算子的特征值和特征的特征函数得到了一类非线性Schroedinger方程初边值问题解Blow-up的条件,补充和完善了张健的结果。     

不定Sturm—Liouville算子的特征函数的振荡问题

研究了定义在有限区间（0，l）上的具有一般分离型边条件的不定Sturm—Liouville算子的特征函数的振荡问题．利用Prufer变换，给出了上述Sturm-Liouville算子特征值的符号指标的具体形式；得到了特征值的符号指标与Weyl函数以及Prufer角在该特征值处的罗朗展式（泰勒展式）的首项系数的符号之间的关系；最后，在上述两个结果的基础上给出了上述Sturm—Liouville算子的第n个正特征值所对应的特征函数在[0，l]内的零点个数的计算公式．     

关于约化波动方程的振荡解

文[1]研究了球对称情况下受迫约化波动方程存在振荡解的充分条件.本文提出一个充分条件,以保证下列波动方程的一切解都是振荡的,这里△是拉普拉斯算符.     

带转移条件的Strum-Liouville问题特征函数的振动性

研究了一类带转移条件的Sturm-Liouville问题在区间(a,c)∪(c,b)上特征函数的振动性,构建了一个与该问题相关的新的Hilbert空间,证明了具有分离边界条件的这类问题的第n个特征值λn(n=1,2,…)所对应的特征函数在区间(a,c)∪(c,b)上有n-1个或n个零点,除此之外,还有-个特征值λ0所对应的特征函数在区间(a,c)∪(c,b)上没有零点.     

离散广义系统的平稳振荡

为了研究离散广义系统的平稳振荡，本文利用广义Ｌｙａｐｕｎｏｖ函数方法，给出了一个ｍ周期解存在的充要条件，得出了离散广义系统的周期解的存在性、唯一性、稳定性的有关定理，进而研究具有某种分解的复杂离散广义系统的平稳振荡问题，方法简单易行．     

一类不连续Strum-Liouville问题特征函数的振动性

研究了-类不连续的Sturm-Liouville问题在开区间(a,c)u(c,b)上特征函数的振动性.构建了一个与其相关的新的Hilbert空间,证明了具有分离边界条件的这类问题的第n个特征值λn(n=1,2,…)所对应的特征函数在区间(a,c)U(c,b)上恰有n-1个零点.     

一类非线性卷积积分方程振荡性的研究

给出了方程ｚ（ｔ）＋∫Ｋ（ｔ－ｓ）Ｇ（ｓ，ｘ（ｓ），ｘ（ｇ（ｓ）））ｄｓ＝ｆ（ｔ）振荡的充分条件与非振荡解的渐近性以及无界解的振荡性。     

约化波动方程的振荡性

本文给出了约化波动方程一切球对称解振荡的充分条件,本文的条件与[2]的条件互为独立,而且研究的方法也不同。     

Lower Bounds for the Nodal Length of Eigenfunctions of the Laplacian

We prove lower bounds for the length of the zero set of aneigenfunction of the Laplace operator on a Riemann surface; inparticular, in non-negative curvature, or when the associated eigenvalueis large, we give a lower bound which involves only the square root ofthe eigenvalue and the area of the manifold (modulo a numericalconstant, this lower bound is sharp).     

Asymptotic Distribution of Eigenfunctions and Eigenvalues of the Basic Boundary-Contact Oscillation Problems of the Classical Theory of Elasticity

The basic boundary-contact oscillation problems are considered for a three-dimensional piecewise-homogeneous isotropic elastic medium bounded by several closed surfaces. Using Carleman's method, the asymptotic formulas for the distribution of eigenfunctions and eigenvalues are obtained.     

Doubling Property and Vanishing Order of Steklov Eigenfunctions

The paper is concerned with the doubling estimates and vanishing order of the Steklov eigenfunctions on the boundary of a smooth domain in ? ⁿ . The eigenfunction is given by a Dirichlet-to-Neumann map. We improve the doubling property shown by Bellova and Lin. Furthermore, we show that the optimal vanishing order of Steklov eigenfunction is everywhere less than Cλ where λ is the Steklov eigenvalue and C depends only on Ω.     

Eigenvalues and Eigenfunctions of the Laplace Operator on an Equilateral Triangle for the Discrete Case

A discretized boundary value problem for the Laplace equation with the Dirichlet and Neumann boundary conditions on an equilateral triangle with a triangular mesh is transformed into a problem of the same type on a rectangle. Explicit formulae for all eigenvalues and all eigenfunctions are given.     

具有脉冲的造血模型的振动性与吸引性

考虑具有脉冲扰动的造血模型,得到了方程非振动解的渐近性及所有解关于平衡点K振动的充分条件,推广了文献中的相关结论.     

Solution Bounds for the Discrete Riccati Equation and Its Applications

In this paper, we address the estimation problem for the solution of the discrete algebraic matrix Riccati equation. Both upper and lower bounds are measured. Compared to the majority of the approaches proposed in the literature, the present results are sharper. We also apply the results obtained to solve the robust stabilization problem of discrete time-delay systems. A robust stabilizability criterion and the corresponding state feedback control law are proposed. Furthermore, the tolerable bound of the delay term is also estimated. Finally, numerical examples are given to demonstrate the applications of the results.     

Oscillation theorems for symplectic difference systems

We consider symplectic difference systems involving a spectral parameter, together with the Dirichlet boundary conditions. The main result of the paper is a discrete version of the so-called oscillation theorem which relates the number of finite eigenvalues less than a given number to the number of focal points of the principal solution of the symplectic system. In two recent papers the same problem was treated and an essential ingredient was to establish the concept of the multiplicity of a focal point. But there was still a rather restrictive condition needed, which is eliminated here by using the concept of finite eigenvalues (or zeros) from the theory of matrix pencils.     

Basis Property of Chains of Eigenfunctions for Certain Boundary-Value Problems

Mathematical Notes -