两不同部件并联可修系统的本征值问题

研究了两不同部件并联可修系统的一个本征值对应一个本征向量的问题以及求解了该系统算子非零解的存在.     

具有热储备可修复平行系统本征值问题

针对具有热储备可修复平行系统模型,得出了一个本征值对应一个本征元的结论并证了除0本征值外还存在另外非零实本征值.     

连续时间LQ控制主要本征对的算法

本文首先提出了离散时间LQ控制的本征值方程当△t→0时怎样退化成为连续时间LQ控制的本征值方程.在建立了分离出的n阶连续时间的本征值方程,并保证了其本征值必定都在左半平面后,本文提出计算其最靠近于虚轴的若干个本征对,可以通过A_e=eA的矩阵变换.A_e的本征值全在单位圆之内.本征向量不变,至于本征值则只要做一次对数运算就可以求得原阵的本征值.A_e阵的最接近于单位圆的若干个本征对的算法,可以通过共轭子空间迭代解解决之.     

可修复人机储备系统算子的本征值问题

讨论了可修复人机储备系统算子的本征值问题,讨论了系统算子非零本征值的存在性,并且系统算子一个本征值对应一个本征向量.     

高阶椭圆算子Dirichlet本征值的下界

设Ω是R^m(m≥2）中的一个有界区域,其边界足够光滑,考察2p(p≥1）阶椭圆算子（－1）^p ∑│α│＝│β│＝pa^α(Aαβa^β)在Dirichlet边界条件下的本征值问题,给出了其本征值的一个下界,该下界除与维数m有关外仅依赖于区域Ω的体积。     

M/M/1/m系统算子的本征值特性(m=4,5)

研究了m=4,5时,M/M/1/m算子本征值特性:二者相应本征值的代数重均为1;二者相应的系统算子的非零本征值相互交替;后者的最大非零本征值逐渐靠近0点;另外给出了m=4,5时,相应的p_0(t)图像.     

M/M/1/m系统算子的本征值特性(m=1,2,3,4)

研究了m=1,2,3,4时,M/M/1/m算子本征值特性:每个模型的相应本征值的代数重均为1;相邻两个模型系统算子的非零本征值相互交替;随着m值的增大,相应的最大非零本征值逐渐靠近0点;给出了m=3,4时,相应的p_0(t)图像.     

基于WKBZ理论的耦合简正波-抛物方程理论

研究水平变化海洋环境中声传播的快速数值预报方法.在广义相积分(WKBZ)理论的基础上,提出了一种能够快速、准确地求解简正波本征值的方法,并将此方法应用于耦合简正波-抛物方程(CMPE) 理论.分析了两种典型声速剖面的简正波本征值,并计算了一个楔形海区中的声传播问题(JASA标准问题).计算结果表明本方法是一种快速而精确的数值方法.     

M/M/1/m系统算子的本征值特性(m=7,8)

研究了m=7,8时,M/M/1/m算子本征值特性:相应本征值的代数重为1;m=7,8时,相应的系统算子的非零本征值相互交替;m=8时的最大非零本征值比m=7时更靠近0点.这种特性延续了m=1,2,3,4,5,6时相应的特性.另外给出了m=7,8时,相应的p_0(t)图像.     

与波动方程边界控制有关的一类本征值问题

本文在高维空间情形，研究了大型空间结构和柔性机器人的控制中提出的一类新型的包含边界双线性形式的本征值问题，利用Ｐｏｈｏｚａｅｖ恒等式，分析了本征元的边界形态．     

Existence of an extremal ground state energy of a nanostructured quantum dot

This paper is concerned with two rearrangement optimization problems. These problems are motivated by two eigenvalue problems which depend nonlinearly on the eigenvalues. We consider a rational and a quadratic eigenvalue problem with Dirichlet’s boundary condition and investigate two related optimization problems where the goal function is the corresponding first eigenvalue. The first eigenvalue in the rational eigenvalue problem represents the ground state energy of a nanostructured quantum dot. In both the problems, the admissible set is a rearrangement class of a given function.     

On the condition numbers of a multiple eigenvalue of a generalized eigenvalue problem

For standard eigenvalue problems, closed-form expressions for the condition numbers of a multiple eigenvalue are known. In particular, they are uniformly 1 in the Hermitian case and generally take different values in the non-Hermitian case. We consider the generalized eigenvalue problem and identify the condition numbers. Our main result is that a multiple eigenvalue generally has multiple condition numbers, even in the Hermitian definite case. The condition numbers are characterized in terms of the singular values of the outer product of the corresponding left and right eigenvectors.     

Eigenvalue analysis for a crack in a power-law material

A nonlinear eigenvalue problem related to determining the stress and strain fields near the tip of a transverse crack in a power-law material is studied. The eigenvalues are found by a perturbation method based on representations of an eigenvalue, the corresponding eigenfunction, and the material nonlinearity parameter in the form of series expansions in powers of a small parameter equal to the difference between the eigenvalues in the linear and nonlinear problems. The resulting eigenvalues are compared with the accurate numerical solution of the nonlinear eigenvalue problem.     

On condition numbers of a nondefective multiple eigenvalue of a nonsymmetric matrix pencil

This paper considers the condition numbers of a nondefective multiple eigenvalue of a nonsymmetric matrix pencil. Based on the directional derivatives of a nondefective multiple eigenvalue of a nonsymmetric matrix pencil analytically dependent on several parameters, different condition numbers of a nondefective multiple eigenvalue are introduced. The computable expressions and bounds of introduced condition numbers are derived. Moreover, some results on the perturbation of a nondefective multiple eigenvalue of a nonsymmetric matrix pencil are given.     

The emergence of eigenvalues of a PT-symmetric operator in a thin strip

The Schrödinger operator in a thin infinite strip with PT -symmetric boundary conditions and a localized potential is studied. The case of a virtual level on the threshold of the essential spectrum of an efficient one-dimensional operator is considered. Sufficient conditions for the transformation of this level into an isolated eigenvalue are obtained and the first terms of the asymptotic expansion are calculated for this eigenvalue. Sufficient conditions for the absence of such an eigenvalue are also obtained.     

Simulation of soliton solutions for the propagation of a femtosecond pulse in a medium with a cubic nonlinearity

Soliton solutions are constructed numerically for the problem of propagation of a femtosecond pulse in a medium with a cubic nonlinearity. The problem is posed as an eigenvalue problem with an operator nonlinear in the eigenfunctions. For given values of the propagation parameter we find the real eigenvalue λ and the corresponding eigenvector. This eigenvector is a soliton, i.e., a solution that does not vary in the coordinate of propagation of the light pulse. An algorithm is proposed to find the minimum eigenvalue and the corresponding eigenfunctions that satisfy given conditions. Translated from Prikladnaya Matematika i Informatika, No. 2, pp. 63–68, 1999.     

Stability For a Multidimensional Inverse Spectral Theorem

We consider the eigenvalue problem in Ω

Where Ω is a bounded domain in R^d with smooth boundary,a nd q is a bounded, measurable function on Ω The eigenvalue problem has discrete spectrum; we denote by and a nondecreasing sequence of eigenvalue and corresponding (orthonormal) eigenfunctions. It is known ([N–S–U]) that knowledge of the eigenvalues and the boundary values of the normal derivatives of the corresponding eigenfunctions is sufficient to uniquely determine a coefficient, q.     

On certain properties of a nonlinear eigenvalue problem for Hamiltonian systems of ordinary differential equations

Properties of the eigenvalues are examined in a nonlinear self-adjoint eigenvalue problem for linear Hamiltonian systems of ordinary differential equations. In particular, it is proved that, under certain assumptions, every eigenvalue is isolated and there exists an eigenvalue with any prescribed index.     

Principal vectors of a nonlinear finite-dimensional eigenvalue problem

In a finite-dimensional linear space, consider a nonlinear eigenvalue problem analytic with respect to its spectral parameter. The notion of a principal vector for such a problem is examined. For a linear eigenvalue problem, this notion is identical to the conventional definition of principal vectors. It is proved that the maximum number of linearly independent eigenvectors combined with principal (associated) vectors in the corresponding chains is equal to the multiplicity of an eigenvalue. A numerical method for constructing such chains is given.     

The Eigenvalue Problem for a One-Dimensional Differential Operator with a Variable Coefficient and Nonlocal Integral Conditions*

We consider conditions for the existence of the eigenvalue λ = 0 in the eigenvalue problem for a differential operator with a variable coefficient and integral conditions. We analyze how these conditions depend on such properties of the coefficient p(x) as monotonicity and symmetry and observe some other properties of the spectrum of the eigenvalue problem. Particularly, we show by a numerical experiment that the fundamental theorem on the increase of the eigenvalues in the case of increasing coefficient p(x) is not valid for the eigenvalue problem with nonlocal conditions.