直接求线性规划可行基的一种方法

本文给出直接求线性规划问题基可行解的一种简易方法,该方法既避免了引入人工变量,减少存储,一般又能较快地得到一个较好的基可行解.     

信天翁近海面飞行时的气动力研究

针对信天翁近海面的飞行条件,研究信天翁能在大风浪中高效飞行的力学机理．将信天翁简化为二维机翼,采用势流理论的面元方法,重点研究了波浪的有益干扰．给出了信天翁在匀速固定高度飞行和自由飞行两种状态下的波浪扰动力．计算结果表明:信天翁的飞行效率不仅取决于飞行的高度和速度,而且取决于浪高和波长;在大风浪下信天翁可以从波浪有益干扰中获得推力来抵消部分飞行阻力,提高飞行效能．     

面积问题中的割补法、极限法与微元法

纵观历史，求平面图形的面积的方法的发展演变过程大致可分为4个阶段，1．运用割补法求多边形的面积；2．运用极限思想求圆的面积；3．将分割与极限结合，形成微元法的雏形，求曲边形的面积；4．微元法的成熟与定积分思想的形成。     

抛物方程的基于BB型对偶剖分的有限体积元法

本文讨论了抛物方程的基于三角形剖分和BB型对偶剖分的有限体积元法,给出了半离散及全离散有限体积元格式的最佳阶L2和H1误差估计.     

接触问题中的快速凝缩消元法

用分离解法求解弹性接触问题时，在增量加载和迭代过程中，由于接触区某些节点的状态发生改变而导致方程组的系数矩阵某些行和列元素随之变化。根据此特点，本推导了一种新的自适应迭代算法-快速凝缩消元法，并给出具体的迭代步骤，避免了系数矩阵变化时必须重新形成矩阵的重复计算。     

COHOMOLOGY VANISHING IN HILBERT SPACES

§1. Introduction Oka [40] proved that any additive Cousin problem is solvable in a domain of holomorphyin Cn. Oka [41]-Cartan [2, 3]-Serre [46] generalized this as the theorem B for analyticcoherent sheaves over Stein spaces. J. P. Serre [47] proved…     

WEIERSTRASS REPRESENTATION FORSURFACES WITH PRESCRIBED NORMALGAUSS MAP AND GAUSS CURVATURE IN H~3

The author obtains a Weierstrass representation for surfaces with prescribed normal Gauss map and Gauss curvature in H3. A differential equation about the hyperbolic Gauss map is also obtained, which characterizes the relation among the hyperbolic Gauss map, the normal Gauss map and Gauss curvature. The author discusses the harmonicity of the normal Gauss map and the hyperbolic Gauss map from surface with constant Gauss curvature in H3 to S2 with certain altered conformal metric. Finally, the author considers the surface whose normal Gauss map is conformal and derives a completely nonlinear differential equation of second order which graph must satisfy.     

两平行圆盘间或两圆球间存在二阶流体时的挤压流动

为了进行湿颗粒群的离散元模拟,研究两圆球颗粒间二阶流体在挤压流动时的法向粘性力．首先用小参数法对两平行圆盘间二阶流体挤压流动的速度场和正应力分布进行了近似分析,然后用类似的方法,分析任意两圆球间二阶流体的挤压流动,得到了压力分布和法向粘性力的解析解．     

非定常的热传导-对流问题的非线性Galerkin混合元法(Ⅲ):时间二阶精度的全离散格式

In this paper, a fully discrete format of nonlinear Galerkin mixed element method with two-step discretization of time for the non stationary conduction-convection problems is presented. The existence and the convergence of the fully discrete mixed element solution are shown. On the basis of [9] and [10], we have proved that the schemes have second-order convergence accuracy for the time discretization.     

A BOUNDARY ELEMENT METHOD FOR A NONLINEAR BOUNDARY VALUE PROBLEM IN STEADY-STATE HEAT TRANSFER IN DIMENSION THREE

In this paper, a new method of boundary reduction is proposed, which reduces thesteady-state heat transfer equation with radiation. Moreover, a boundary element method is pre-sented for its solution and the error estimates of the numerical approximations are given.