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941.
Kun-fu Fang 《应用数学学报(英文版)》2012,28(1):193-200
Let Gnk denote a set of graphs with n vertices and k cut edges. In this paper, we obtain an order of the first four graphs in Gnk in terms of their spectral radii for 6 ≤ k ≤ (n-2)/3. 相似文献
942.
《Applicable analysis》2012,91(1):1-12
ABSTRACTThe problem of normal waves in a closed (shielded) regular waveguide of arbitrary cross-section is considered. This problem is reduced to the boundary eigenvalue problem for longitudinal components of electromagnetic field in Sobolev spaces. To find the solution, we use the variational formulation of the problem. The variational problem is reduced to study an operator-function. Discreteness of the spectrum is proved and distribution of the characteristic numbers of the operator-function on the complex plane is found. We also consider properties of system of eigenvectors and associated vectors of the operator-function. Double completeness of system of eigenvectors and associated vectors with a finite defect is established. 相似文献
943.
利用多项式Euclid算法给出了非奇异m重对角因子循环矩阵求逆的一个新算法,并将该算法推广至求m重对角因子循环矩阵的群逆和Moore-Penrose逆,及给出了具体的求逆步骤. 相似文献
944.
夏立标 《浙江大学学报(理学版)》2014,41(4):391-398
过去的半个多世纪,传染病模型在数学生态学领域已受广泛重视.研究了一个具时滞和扩散的传染病模型,重点讨论了该模型解的定性性质和稳态解的渐近行为;利用线性化和特征值方法讨论了正稳态解的局部稳定性,通过构造单调迭代序列,给出了正稳态解的全局稳定性. 最后给出了数值模拟和讨论,当接触率充分小时,问题的无病平衡点是全局渐近稳定的. 相似文献
945.
In this paper, an extremal eigenvalue problem to the Sturm-Liouville equations with
discontinuous coefficients and volume constraint is investigated. Liouville
transformation is applied to change the problem into an equivalent minimization
problem. Finite element method is proposed and the convergence for the finite
element solution is established. A monotonic decreasing algorithm is presented
to solve the extremal eigenvalue problem. A global convergence for the algorithm
in the continuous case is proved. A few numerical results are given to depict the
efficiency of the method. 相似文献
946.
A multiple monopole (or multipole) method based on the generalized mul- tipole technique (GMT) is proposed to calculate the band structures of scalar waves in two-dimensional phononic crystals which are composed of arbitrarily shaped cylinders embedded in a host medium. In order to find the eigenvalues of the problem, besides the sources used to expand the wave field, an extra monopole source is introduced which acts as the external excitation. By varying the frequency of the excitation, the eigenvalues can be localized as the extreme points of an appropriately chosen function. By sweeping the frequency range of interest and sweeping the boundary of the irreducible first Brillouin zone, the band structure is obtained. Some numerical examples are presented to validate the proposed method. 相似文献
947.
姚庆六 《浙江大学学报(理学版)》2012,39(4):381-384
考察了一类复合型非线性三阶三点边值问题的正解,其中非线性项f(t,u)可以在t=0,t=1及u=0处奇异.利用锥压缩与锥拉伸型的Krasnosel'skii不动点定理建立了几个正解存在定理.当f(t,u)超线性和次线性时,这些存在定理推广了现有的结论. 相似文献
948.
949.
950.
A two-level stabilized finite element method for the Stokes eigenvalue problem based on the local Gauss integration is considered.This method involves solving a Stokes eigenvalue problem on a coarse mesh with mesh size H and a Stokes problem on a fine mesh with mesh size h = O(H 2),which can still maintain the asymptotically optimal accuracy.It provides an approximate solution with the convergence rate of the same order as the usual stabilized finite element solution,which involves solving a Stokes eigenvalue problem on a fine mesh with mesh size h.Hence,the two-level stabilized finite element method can save a large amount of computational time.Moreover,numerical tests confirm the theoretical results of the present method. 相似文献