数值算法

The numerical non-stability of a discrete algorithm of topology optimization can result fi＇om the inaccurate evaluation of element sensitivities, especially, when material is added to elements.

单元敏度的不准确估计是离散拓扑优化算法数值不稳定的原因之一，特别是添加材料时，传统的敏度计算公式给出的估计误差较大，甚至有时估计符号都是错误的。

The simulation Connection of distributary ratio and separate efficiency compared with the experimentation data and the relative error is within 15%.

从而说明本文所采用的数学模型及算法对复合式水力旋流器内部流场的数值计算是可行的。

The unique class unit which makes up the deployable structures,'scissor-like element',is treated as a macro element.Formulation for duplet stiffness is derived.And the linear elastic response is investigated numerically using this formulation.Owing to the introduction of a novel type of macro element,the number of degrees of freedom is reduced,and the solution efficiency is increased.

将可展结构的特有单元——剪式单元作为一个宏单元来考虑，推导了宏单元的刚度矩阵，并用于可展结构线弹性响应的数值分析，减少了总体自由度，提高了算法效率。

Some numerical results show that this algorithm is accurate and ef...

并利用一些数值结果证实了这些算法的有效性。

Numerical experiments show that the new algorithm is more effective in realizing the high convergence speed, convergence precision, reducing the convergence algebra and good at keeping the stability of the adaptive genetic algorithm.

数值实验表明：新算法在提高收敛速度和收敛精度、减少收敛代数方面效果显著，稳定性也有所提高。

Mathieu functions are frequently encountered in many radiation,scattering and guided wave problems, which are formulated in the elliptic cylindrical coordinate system.

本文给出了计算马丢函数和变型马丢函数及其导数值的程序流图和相应的有用数学公式，并讨论了算法。

The model is proved to satisfied user equilibrium condition and other constraint conditions.

模型被证明满足用户平衡条件和相关约束条件，并可利用以有限元算法为基础的迭代解法求得模型的数值解，从而计算出竞争性公共交通枢纽设施的市场份额。

Compared with standard Crank-Nicholsonscheme in the same computational time and resource, the method has two characteristics: small truncation error of in the transverse direction and high accuracy. It is a useful tool for designing optical waveguide devices.

与标准格式的有限差分光束传播法相比，该算法在几乎不增加计算时间和计算机内存资源的情况下，结合了道(来源：122eA22BC论文网www.abclunwen.com)格拉斯格式的有限差分光束传播法截断误差小和宽角多步法所具有较高精度的优点，是光波导器件理想的数值模拟工具。

Based on Crank-Nicoson's technique, and a new approach for the numerical simulation of the model is raised. The truncation error of the one step difference method reaches O (△t^2+△x^2) and of quite good stability condition.

基于Coriolis加速度和Lagrangian应力公式，利用Newton第二定律导出轴向加速度运动弦线横向振动的动力学模型；通过线性变换将方程化为一阶无量纲的非线性微分方程组；并利用Crank-Nicoson的中点离散技巧，给出运动方程的单步二阶差分方法；算法把对运动方程和本构方程分别离散，使之可以用于不同本构的运动弦线的数值仿真。

In this paper the effects of scanning truncation error, scanning position error, random amplitude and phase error, and multiple-reflection error in near-field antenna measurement are analyzed; error equations and the uncertainty of measurement are obtained through computer simulation; compensated techniques for reducing the effects of measurement errors in near-field antenna measurement are presented and the formula and arithmetic of phaseless near-field techniques are derived.

本文从解析法和数值仿真两个角度深入分析口面天线近场测量中扫描面截断误差、扫描面位置误差、随机幅相误差、多次反射误差等误差源对天线远场特性测量精度的影响，一方面从理论上给出相应的误差方程，另一方面建立误差分析模型，通过计算机模拟，得到不同误差条件下测量结果的不确定度，并介绍了减小这些误差的修正方法，推导无相位近场测量的公式和算法。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。