Existence of homoclinic solutions for a class of second-order Hamiltonian systems

A new result for existence of homoclinic orbits is obtained for the second-order Hamiltonian systems under a class of new superquadratic conditions. A homoclinic orbit is obtained as a limit of solutions of a certain sequence of boundary-value problems which are obtained by the minimax methods.     

THE RELATION BETWEEN SIGN-CHANGING SOLUTION AND POSITIVE-NEGATIVE SOLUTIONS FOR NONLINEAR OPERATOR EQUATIONS AND ITS APPLICATIONS

By fixed point index theory and a result obtained by Amann, existence of the solution for a class of nonlinear operator equations x=Ax is discussed. Under suitable conditions, a couple of positive and negative solutions are obtained. Finally, the abstract result is applied to nonlinear Sturm-Liouville boundary value problem, and at least four distinct solutions are obtained.     

On the stability and spectral radius of a finite set of matrices

This paper studies some problems related to the stability and the spectral radius of a finite set of matrices. A seasonal epidemic model is given to illustrate the use of the obtained results. In this example, the relationship between the obtained results and the stability of a discrete time periodic linear system is obtained.     

Hopscotch method: The numerical solution of the Frank-Kamenetskii partial differential equation

Numerical solutions to the Frank-Kamenetskii partial differential equation modelling a thermal explosion in a cylindrical vessel are obtained using the hopscotch scheme. We observe that a nonlinear source term in the equation leads to numerical difficulty and hence adjust the scheme to accommodate such a term. Numerical solutions obtained via MATLAB, MATHEMATICA and the Crank-Nicolson implicit scheme are employed as a means of comparison. To gain insight into the accuracy of the hopscotch scheme the solution is compared to a power series solution obtained via the Lie group method. The numerical solution is also observed to converge to a well-known steady state solution. A linear stability analysis is performed to validate the stability of the results obtained.     

Existence of even homoclinic orbits for second-order Hamiltonian systems

Some existence theorems for even homoclinic orbits are obtained for a class of second-order nonautonomous Hamiltonian systems with symmetric potentials under a class of new superquadratic conditions. A homoclinic orbit is obtained as a limit of solutions of a certain sequence of nil-boundary-value problems which are obtained by the minimax methods.     

关闭一启动型多级适应性休假M^x／G／1排队系统的随机分解

本文采用一种较简单的分析方法，讨论了队长分布的瞬态和稳态性质，得到了队长瞬态分布的拉普拉斯变换的递推表达式和稳态分布的递推表达式，以及稳态队长的随机分解，并给出了服务台闲期、服务台忙循环期的分布函数。     

Generalized Ito's formula and additive functionals of Brownian motion

Summary An extension of Ito's formula to convex functions is obtained, and a version of its converse is investigated. By using the generalized Ito's formula obtained here and that obtained by G. Brosamler for higher dimensional Brownian motion, a transparent proof of the correspondence between measures and nonnegative continuous (homogeneous) additive functionals is given.     

有限元超收敛新论

本文从三个方面讨论二阶椭圆问题有限元超收敛．1．一致网格上的新超收敛结果．利用新的“投影型插值”,我们解决了高次三角形元的超收敛问题．2．一般网格的超收敛性．利用局部插值处理和局部磨光处理我们获得了整体超收敛性结果．3．关于当前的两种超收敛技巧．Cornell学派利用一个精致的内估计和网格的点对称性,获得了一个“普遍”的结果,中国学派利用两个基本估计和离散Green函数理论获得了令人满意的结果,两者均很复杂．本文综合了两个学派的方法,简洁地证得上述普遍结果．     

Optical solitons with time-dependent dispersion,nonlinearity and attenuation in a power-law media

This paper studies optical solitons in a power-law media with time-dependent coefficients of dispersion, nonlinearity and attenuation. The 1-soliton solution is obtained for the nonlinear Schrödinger’s equation with power-law nonlinearity. In addition, a relation between these coefficients is obtained for the solitons to exist. Finally, the velocity of the soliton is also obtained in terms of these coefficients.     

Multimode Relativistic String: Classical Solutions and Quantization

We find all independent classical solutions for the three-mode Nambu–Goto string. We investigate the geometry of the closed curves obtained. Canonical quantization is performed for a part of the solutions obtained. We consider the spectrum of the quantum states obtained. It is consistent with the experimental masses and quantum numbers of mesons corresponding to glueballs. The leading Regge trajectory of the obtained states is consistent with the available data on the Pomeron trajectory.Deceased     

On Generalized Orthodox Transversals

Generalized orthodox transversals are introduced in this article, and some characterizations associated with them are obtained. The related results of Chen on quasi-ideal orthodox transversals obtained in 1999 and Zhang and Wang on generalized inverse transversals obtained in 2008 are generalized and amplified. A structure theorem of a regular semigroup with a perfect generalized orthodox transversal is also established.     

The effect of redundancy on probability bounds

Lower bounds on the probability of a union obtained by applying optimal bounds to subsets of events can provide excellent bounds. Comparisons are made with bounds obtained by linear programming and in the cases considered, the best bound is obtained with a subset that contains no redundant events contributing to the union. It is shown that redundant events may increase or decrease the value of a lower bound but surprisingly even removal of a non-redundant event can increase the bound.     

Continuity of second-order contingent derivative of the efficient set map for parametrized multiobjective optimization

In this paper, some relationships between the second-order contingent derivative of a set-valued map and its profile map are obtained. By virtue of the second-order contingent derivatives of set-valued maps, upper semicontinuity and lower semicontinuity are obtained for efficient set maps of parametrized multiobjective optimization. Several examples are provided to show the results obtained.     

On the maximal multiplicative complexity of a family of bilinear forms

The number of nonscalar multiplications required to evaluate a general family of bilinear forms is investigated. An upper bound is obtained which is about half that obtained from naive arguments. In certain cases the best possible upper bound is obtained.     

A numerical model of turbulent shear flow behind a prolate spheroid

A finite element based computer model is developed to simulate turbulent shear flow. The results obtained from the model are compared with numerical finite difference based calculations and experimentally determined values associated with flow behind a prolate spheroid. The results obtained utilizing a velocity-pressure formulation are, in the region immediately downstream of the spheroid, markedly better than those obtained under the standard assumption of zero pressure gradient boundary layer flow.     

稠定闭线性算子的剩余谱刻画及其应用

得到Hilbert空间中的稠定闭线性算子的剩余谱由其点谱及其共轭算子点谱完全刻画,由此给出了其剩余谱为空集的充要条件;从而得到两类稠定闭线性算子的谱结构.     

Integration by Parts for Poisson Processes

Using a perturbation of the rate of a Poisson process and an inverse time change, an integration by parts formula is obtained. This enables a new form of the integrand in a martingale representation result to be obtained.     

The exact boundaries of the stability domains of linear differential equations with distributed delay

For a differential equation with a distributed varying delay, sufficient criteria for the asymptotic and uniform stability of solutions are obtained. The constructed examples demonstrate exactness of the boundary of the obtained stability domain.     

矩阵复合型谱包含域的改进及应用

本文研究了矩阵的复合型谱包含域,给出了边界定理,得到了改进的复合型谱包含域,作为应用得到了非奇异H-矩阵的更精确的判别条件．     

Dynamic and static loss in stability of flexible spherical shells made out of a composite material

The dynamic and static stability of shallow spherical shells which are rectangular in a plane are investigated. It is assumed that the shell is made out of a composite material which is weakly shear resistant and hence the refined theories which allow for transverse shear deformations and rotational inertia are applied. The solutions which were obtained are compared with solutions founded on the basis of the Kirchhoff-Love theory. It is shown that the results which are obtained on the basis of the classical theory are high for both the static and dynamic loss in stability, and are qualitatively different from the results obtained using the refined theory. The solutions were obtained using the Bubnov-Galerkin method in the higher approximations.