一维半导体器件的特征有限体积元方法及分析

1、引言 有限体积元方法作为求解微分方程的一种新技术,日益受到普遍关注．本文将特征线方法与有限体积元方法相结合,构造出特征有限体积元方法,该方法综合了特征有限差分方法和特征有限元方法的主要优点,与特征有限差分方法相比,     

传统隐式Runge-Kutta方法的转换方法

多级隐式Runge-Kutta(RK)方法簇中,除Gauss类方法是s级2s阶的辛方法以外,Radau类方法和Lobatto类方法既不是s级2s阶的方法也不是辛方法.基于隐式RK方法是一类转换RK方法这一特征,利用V-变换和Pade对角逼近,提出了构造高阶RK方法的转换定理.依据转换定理,导出了s级2s阶的Radau方法和s级2s阶的Lobatto方法.利用V-变换和待定系数法,导出了辛Radau方法和辛Lobatto方法.在此基础上,发现并证明了辛Radau方法是s级2s阶的方法.     

威布尔分市场合无失效数据的可靠性分析

拿文综合了近几年来对威布尔分布和指数分布的无失效数据处理的几种方法这些方法是经典方法、贝叶斯方法、最小x~2方法、等效失效敷方法,并对这些方法作了适当的分析,提出进一步需研究的问题。     

系统科学在数学教育中的渗透

对于自然科学和社会科学具有普适性的系统科学理论,已不断渗透到数学教育的研究领域。本文试谈几种系统科学方法:系统方法、信息方法、反馈方法、黑箱方法、运筹学方法及功     

威布尔分布场合无失效数据的可靠性分析

本文综合了近几年来对威布尔分布和指数分布的无失效数据处理的几种方法，这些方法是经典方法、贝叶斯方法、最小ｘ＾２方法、等效失效数方法，并对这些方法作了适当的分析，提出进一步需研究的问题。     

几类改进的新的两步六阶Chebyshev-Halley方法

利用权函数法,给出非线性方程求根的Chebyshev-Halley方法的几类改进方法,证明方法六阶收敛到单根.Chebyshev-Halley方法的效率指数为1.442,改进后的两步方法的效率指数为1.565.最后给出数值试验,且与牛顿法,Chebyshev-Halley 方法及其它已知的方程求根方法做了比较.结果表明方法具有一定的优越性.     

NGLM:一类全局收敛的Newton-GMRES方法

本文提出了一类具有全局收敛性质的Newton-GMRES方法—NGLM方法．该方法是对经典Newton—GMRES方法的推广．NGLM方法的全局策略是当在非精确Newton方向上后退不能成功时，转而在一个子空间上运用信赖域方法确定迭代步长．理论分析与数值实验均表明，NGLM方法改善了Newton—GMRES方法的强健性．     

关于线性互补问题的模系矩阵分裂迭代方法

模系矩阵分裂迭代方法是求解大型稀疏线性互补问题的有效方法之一.本文的目标是归纳总结模系矩阵分裂迭代方法的最新发展和已有成果,主要内容包括相应的多分裂迭代方法, 二级多分裂迭代方法和两步多分裂迭代方法, 以及这些方法的收敛理论.     

一种改进的Adomian分解方法

给出了一种新的改进Adomian分解方法,新方法能有效地解决传统Adomian分解方法及其改进方法的不足.将新改进方法应用于第二类Volterra积分方程、积分-微分方程求解,并与传统Adomian分解方法及其改进方法作比较分析,结果表明提出的新改进方法能返回方程精确解析解.     

大密度比和大压力比可压缩流的数值计算

将WENO方法、RKDG方法、RKDG方法结合原来的Ghost Fluid方法以及RKDG方法结合改进的Ghost Fluid方法,应用到大密度比和大压力比的单相流以及气-气、气-液两相流的数值计算,并对计算结果进行了比较分析．结果表明,与其它的方法相比,RKDG方法结合改进的Ghost Fluid方法得到了高分辨率的计算结果,可以捕捉到正确的激波位置,随着网格的加密,计算解收敛到物理解．     

An achievement rate approach to linear programming problems with an interval objective function

In this paper, we focus on a treatment of a linear programming problem with an interval objective function. From the viewpoint of the achievement rate, a new solution concept, the maximin achievement rate solution, is proposed. Nice properties of this solution are shown: a maximin achievement rate solution is necessarily optimal when a necessarily optimal solution exists, and if not, then it is still a possibly optimal solution. An algorithm for a maximin achievement rate solution is proposed based on a relaxation procedure together with a simplex method. A numerical example is given to demonstrate the proposed solution algorithm.     

Sequential Linear-Quadratic Method for Differential Games with Air Combat Applications

We present a numerical method for computing a local Nash (saddle-point) solution to a zero-sum differential game for a nonlinear system. Given a solution estimate to the game, we define a subproblem, which is obtained from the original problem by linearizing its system dynamics around the solution estimate and expanding its payoff function to quadratic terms around the same solution estimate. We then apply the standard Riccati equation method to the linear-quadratic subproblem and compute its saddle solution. We then update the current solution estimate by adding the computed saddle solution of the subproblem multiplied by a small positive constant (a step size) to the current solution estimate for the original game. We repeat this process and successively generate better solution estimates. Our applications of this sequential method to air combat simulations demonstrate experimentally that the solution estimates converge to a local Nash (saddle) solution of the original game.     

Global efficiency in multiobjective programming *

In this paper, we are concerned with global efficiency in multiobjective optimization. After exposing a property of a cone-subconvexlike function, we prove that a local weakly efficient solution, a local efficient solution and a local properly efficient solution are respectively a global weakly efficient solution, a global efficient solution and a global properly efficient solution of a multiobjective programming problem if cone- subconvexlikeness or cone-pre-invexity is assumed     

一类拟线性常微分方程的多解

说明一类拟线性特征值问题有两个正解;一个大解,一个小解。同时本也证明小解是一个山路解当参数大时发展成为尖解。     

A note on the Helmholz oscillator

The possible existence of a potentially chaotic soliton solution of an unperturbed classical oscillator is investigated. It is shown that in general the solution of the so-called “Helmholz oscillator” is a periodic solution. Special solutions are also found where a localized soliton solution or a decaying solution is obtained depending on the initial conditions.     

AF—代数的闭的Jordan理想

讨论AF-代数的闭的Jordan理想。我们证明了AF-代灵敏的一个闭的子集是其一Jordan理想的充分必要条件是它是一个结合理想。     

Periodic solutions in n dimensions and Volterra equations

If a nonlinear autonomous n-dimensional system of ordinary differential equations has a bounded solution with a certain uniform stability property, this solution approaches an almost periodic solution with the same stability property. (More precisely, the almost periodic solution is in the set of ω-limit points of the given solution.) If the bounded solution has, in addition to the uniform stability property, an asymptotic stability property, then the solution approaches a periodic solution with the same stability properties. Practical (i.e., computable) sufficient conditions for boundedness of solutions are obtained. The results are applied to generalized Volterra equations.     

Minimax regret solution to multiobjective linear programming problems with interval objective functions coefficients

The current paper focuses on a multiobjective linear programming problem with interval objective functions coefficients. Taking into account the minimax regret criterion, an attempt is being made to propose a new solution i.e. minimax regret solution. With respect to its properties, a minimax regret solution is necessarily ideal when a necessarily ideal solution exists; otherwise it is still considered a possibly weak efficient solution. In order to obtain a minimax regret solution, an algorithm based on a relaxation procedure is suggested. A numerical example demonstrates the validity and strengths of the proposed algorithm. Finally, two special cases are investigated: the minimax regret solution for fixed objective functions coefficients as well as the minimax regret solution with a reference point. Some of the characteristic features of both cases are highlighted thereafter.     

(2+1)维AKNS方程的行波解研究(英文)

Based on the travelling wave method, a(2 + 1)-dimensional AKNS equation is considered. Elliptic solution and soliton solution are presented and it is shown that the soliton solution can be reduced from the elliptic solution. It also proves that the result is consistent with the soliton solution of simplify Hirota bilinear method by Wazwaz and illustrate the solution are right travelling wave solution.     

A bifurcation phenomenon in a singularly perturbed two-phase free boundary problem of phase transition

In this paper, we prove a bifurcation phenomenon in a two-phase, singularly perturbed, free boundary problem of phase transition. We show that the uniqueness of the solution for the two-phase problem breaks down as the boundary data decreases through a threshold value. For boundary values below the threshold, there are at least three solutions, namely, the harmonic solution which is treated as a trivial solution in the absence of a free boundary, a nontrivial minimizer of the functional under consideration, and a third solution of the mountain-pass type. We classify these solutions according to the stability through evolution. The evolution with initial data near a stable solution, such as the trivial harmonic solution or a minimizer of the functional, converges to the stable solution. On the other hand, the evolution deviates away from a non-minimal solution of the free boundary problem.