均布载荷下正交异性变厚度圆薄板大挠度问题

本文导出了正交各向异性变厚度圆薄板大挠度问题的基本方程,用修正迭代法求解了正交各向异性变厚度圆薄板在均布载荷下的大挠度问题.作为特例,令ε=0,则由本文结果得到的表达式与J.Nowinski用摄动法得到的正交各向异性等厚度圆薄板大挠度问题的解完全一致.     

变厚度圆柱型正交各向异性圆形薄板的非线性非对称弯曲问题

本文首先导出变厚度圆柱型正交各向异性圆形薄板的非线性非对称弯曲的基本方程，利用“两变量法”，引进四个小参数，对厚度线性变化的圆柱型正交各向异性圆形薄板的非线性非对称弯曲问题进行研究，得到了挠度函数W（r，θ）和应力函数F（r，θ）对ε1为N阶及对ε2为M阶的一致有效渐近解．     

弹性地基上正交各向异性变厚度圆薄板的大挠度问题

本文推出了均布载荷下弹性基地上的正交各向异性变厚度圆薄板大挠度问题的基本方程。利用修正迭代法获得了该问题的二阶近似解。     

变厚度矩形薄板的线性和非线性理论的弹性平衡问题的Navier解

本文研究了四边简支变厚度矩形薄板的线性和非线性理论的弹性平衡问题.文中采用了Navier法,探索了求解的一般途径,并以示例说明求解的具体方法.最后,除提及解的收敛性外,还指出扩大解的应用范围的问题.     

变厚度圆薄板在均布载荷下大挠度问题

本文首先给出变厚度圆薄板大挠度方程,用小参数方法和修正迭代法联合求解此问题,得到三次近似解;给出特征曲线同线性理论进行了比较.     

变厚度圆薄板非对称非线性弯曲问题

首先将直角坐标系中的横向变厚度薄板的大挠度方程,转化到极坐标系中的变厚度圆薄板的非对称大挠度方程·　此方程和极坐标系中径向、切向两个平衡方程联立求解·　将物理方程和中面应变非线性变形方程,代入3个平衡方程,可得用3个变形位移表示的3个非对称非线性方程·　用Fourier级数表示的解代入基本方程,获得相应的基本方程·　在周边夹紧边界条件下,用修正迭代法求解·　作为算例,研究了余弦形式载荷作用下的问题,还给出了载荷与挠度的特征曲线,曲线依据变厚度参数变化而变化,其结果和物理概念完全吻合·     

变厚度簿板弯曲问题的任意网格差分解法

本文提出一种求解变厚度薄板弯曲问题的任意网格差分格式,可适应不同边界,各种荷载和复杂形状板.计算实例表明,该方法具有格式简单、通用性强、计算精度高,计算量少等特点.     

对“变厚度圆薄板在均布载荷下大挠度问题”解法的讨论

文献[1]用小参数法和修正迭代法联合求解了“变厚度圆薄板在均布载荷下的大挠度问题”,文[1]中所得到的解以及各种特殊情况都是正确的.但文[1]中求解步骤仍属于摄动法的求解过程,并且文[1]中将载荷项设为:     

变厚度扁锥壳的非线性固有频率

借助于变厚度圆薄板非线性动力学变分方程和协调方程,给出了变厚度扁薄锥壳的非线性动力学变分方程和协调方程·　假设薄膜张力由两项组成,将协调方程化为两个独立的方程,选取变厚度扁锥壳中心最大振幅为摄动参数,采用摄动变分法,将变分方程和微分方程线性化·　对周边固定的圆底变厚度扁锥壳的非线性固有频率进行了求解;一次近似得到了变厚度扁锥壳的线性固有频率,三次近似得到了变厚度扁锥壳的非线性固有频率,且绘出了固有频率与静载荷、最大振幅、变厚度参数的特征曲线图·　为动力工程提供了有价值的参考·     

在复合载荷作用下变厚度圆薄板大挠度问题

本文用变厚度板壳大挠度理论的修正迭代法[1],对周边固定,在复合载荷下的变厚度圆薄板进行了求解,从而得到了精确度较高的二次近似解析解.将本文的结果退化到特殊情况就可以得到和文[1、2]完全一致的结果.本文还绘出特征曲线进行比较,其结果是理想的.     

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.     

Vanishing pressure limits of Riemann solutions to the isentropic relativistic Euler system for Chaplygin gas

The Riemann solutions to the isentropic relativistic Euler system for Chaplygin gas with a small parameter are considered. Unlike the polytropic or barotropic gas cases, we find that firstly, as the parameter decreases to a certain critical number, the two-shock solution converges to a delta shock wave solution of the same system. Moreover, as the parameter goes to zero, that is, the pressure vanishes, the solution is nothing but the delta shock wave solution to the zero-pressure relativistic Euler system. Meanwhile, the two-rarefaction wave solution tends to the vacuum solution to the zero-pressure relativistic system, and the solution containing one rarefaction wave and one shock wave tends to the contact discontinuity solution to the zero-pressure relativistic system as pressure vanishes.     

第一类不适定算子方程的解的表示

该文在L2中讨论了第一类算子方程Au＝f当A-1无定义和A-1不是单值的情形下的不适定求解问题，给出了解存在的充要条件，当有解时，得到了形式解，多解时形式解就是最小范数解，并且得到了近似解表达式，给出了误差估计．     

New travelling wave solutions for a nonlinearly dispersive wave equation of Camassa-Holm equation type

In this paper, the integral bifurcation method is used to study a nonlinearly dispersive wave equation of Camassa-Holm equation type. Loop soliton solution and periodic loop soliton solution, solitary wave solution and solitary cusp wave solution, smooth periodic wave solution and non-smooth periodic wave solution of this equation are obtained, their dynamic characters are discussed. Some solutions have an interesting phenomenon that one solution admits multi-waves when parameters vary.     

Optimality conditions for vector equilibrium problems

In this paper, we present the necessary and sufficient conditions for weakly efficient solution, Henig efficient solution, globally efficient solution, and superefficient solution to the vector equilibrium problems with constraints. As applications, we give the necessary and sufficient conditions for corresponding solution to the vector variational inequalities and vector optimization problems.     

多目标优化问题McRow最优解的刻画

基于多目标优化问题的McRow模型,该文确定了W-鲁棒有效解(也称为McRow最优解)与弱有效解、有效解以及真有效解的关系.首先, 针对确定多目标优化问题,研究了W-鲁棒有效解与各种精确解的关系.随后,针对随机多目标优化问题,引进McRow最优解的概念,给出了它与其余各种解的关系.算例表明,利用McRow模型所得到的解更具有鲁棒性.     

A new BCR method for coupled operator equations with submatrix constraint

In the present work, a new biconjugate residual algorithm (BCR) is proposed in order to compute the constraint solution of the coupled operator equations, in which the constraint solution include symmetric solution, reflective solution, centrosymmetric solution and anti-centrosymmetric solution as special cases. When the studied coupled operator equations are consistent, it is proved that constraint solution can be convergent to the exact solutions if giving any initial complex matrices or real matrices. In addition, when the studied coupled operator equations are not consistent, the least norm constraint solution above can also be computed by selecting any initial matrices. Finally, some numerical examples are provided for illustrating the effectiveness and superiority of new proposed method.     

The Rayleigh–Stokes problem for an edge in a generalized Oldroyd-B fluid

The velocity field corresponding to the Rayleigh–Stokes problem for an edge, in an incompressible generalized Oldroyd-B fluid has been established by means of the double Fourier sine and Laplace transforms. The fractional calculus approach is used in the constitutive relationship of the fluid model. The obtained solution, written in terms of the generalized G-functions, is presented as a sum of the Newtonian solution and the corresponding non-Newtonian contribution. The solution for generalized Maxwell fluids, as well as those for ordinary Maxwell and Oldroyd-B fluids, performing the same motion, is obtained as a limiting case of the present solution. This solution can be also specialized to give the similar solution for generalized second grade fluids. However, for simplicity, a new and simpler exact solution is established for these fluids. For β → 1, this last solution reduces to a previous solution obtained by a different technique.      

The Rayleigh–Stokes problem for an edge in a generalized Oldroyd-B fluid

The velocity field corresponding to the Rayleigh–Stokes problem for an edge, in an incompressible generalized Oldroyd-B fluid has been established by means of the double Fourier sine and Laplace transforms. The fractional calculus approach is used in the constitutive relationship of the fluid model. The obtained solution, written in terms of the generalized G-functions, is presented as a sum of the Newtonian solution and the corresponding non-Newtonian contribution. The solution for generalized Maxwell fluids, as well as those for ordinary Maxwell and Oldroyd-B fluids, performing the same motion, is obtained as a limiting case of the present solution. This solution can be also specialized to give the similar solution for generalized second grade fluids. However, for simplicity, a new and simpler exact solution is established for these fluids. For β → 1, this last solution reduces to a previous solution obtained by a different technique.     

x^2＋y^2=N^2正整数解的结构与求法

研究勾股方程给定正整数N时,方程是否有解,有几组解,怎样求解.在证明N的解与N的因数的基本解和本原解三者之间存在着一一对应关系的基础上,利用素数的本原解和两组本原解的勾股积运算,经逐次递推,导出了计算N的各种不同类型因数的本原解的计算方法,得到了计算任意N的所有解的简捷方法,并给出了计算全部解的组数的初等公式.填补了多年来研究勾股数的一个空白.