近似法

Rosen projective gradient method is used to find the approximated KKT points of relaxed problem, and then the index set is updated until the minimal solution is .

本文采用Rosen 投影梯度法求此松弛问题的近似KKT点，然后更新指标集不断迭代直至得到最优解。

With the help of Lagrange multipliers, we obtain the optimal approximate merging surface with minimal distance.

为得到与原曲面距离最小的近似合并曲面，只需要利用Lagrange乘子法解决带线性约束的条件极值即可。

Algebraic formulas for calculation of modal field with given approximate value of propagation constant are also presented .

导出了用微扰法计算渐变折射率平面波导传播常数各级近似值的代数递推公式，并给出了由传播常数近似值计算模场近似表达式的代数公式。

A new flux expansion nodal method was developed to solve three-dimensional multigroup neutron diffusion equations in hexagonal-z geometry. The method expands the intranodal homogeneous flux distributions in analytic basis functions for each energy group.

提出了一种在三维六角形几何节块内数值求解多群中子扩散方程的节块法，该方法把节块内各群中子通量分布用解析基函数近似展开。

Then based on the results, the characteristics of radar stealth of a naval vessel were analyzed.

建立以某舰船为参照的艏向与正横向的近似二维模型，基于二维时域有限差分法计算舰船的艏向与正横向在不同频率入射波情况下的雷达散射截面，并根据计算结果对某舰船的雷达隐身特性进行分析。

The non symmetric vibrating character of shaking table is an important factor influencing on shaking table separation and is also the main basis for determining correctly the parameters of shaking table .

针对这一问题，根据实测的摇床振动位移曲线，利用频率分析法和近似积分的原理，采用 E1、E2和 C参数的差动特性系数对摇床差动特性进行了综合评定。

The approximate solutions have advantages of simplicity,practicality,and higher accuracy,which is of practical value in calculating nonlinear oscillations .

利用线化和校正法所求得的近似解与数值解比较，具有简单实用、精度高、相对误差低等优点，在求解非线性振动中具有一定的实用价值。

Based on this, this paper develops the modal series method, expounds its mathematic foundation and theory system, and compares it with the linear modal analysis and the method of norm form of vector fields.

开发了基于模态级数法的HVDC/AC互联电力系统分析软件包，通过此软件可以得到系统的非线性响应，获得非线性系统零输入响应的近似闭式解，进行系统模态分析、非线性模态交互作用分析，并为控制系统设计提供有价值的特征信息。

A series of numerical examples show that the approximation results by these perturbation methods can reach well precision.

通过数值算例表明了通过这些摄动法求得的近似解都可以达到很好的精度。

The main results can beexpressed as follows:(1)Based on πtheory, some affected factors about wave forces are given, and therelation between affected factors and wave forces is analysised by experimentalresults.(2) The distribution of wave press at representative time and reflection nature aregiven and their variety charactes are discussed by experimental results.(3)By comparing the wave forces of quarter-circular breakwater and semi-circularbreakwater under the same wave conditions,some approximately wave forcesexpressions of quarter-circular breakwater are given.(4)Based on VOF method to trace water free surface,solve numerical value ofRANS equation,and get the distributions of flow field and wave press ofquarter-circular breakwater at the same time during one period,the mechanism ofwave force is also discussed elementarily.(5) Based on the result that RANS equation of numerical simulation agree wellwith experimental results,a new approach to study hydraulic natures of quarter-circular breakwater is provided.

其主要结论如下：一、通过π定理，确定影响波浪力的无因次参变量，根据试验结果对其影响因素进行分析；二、基于模型试验，给出典型时刻圆弧面防波堤的同步波压分布和反射特性，讨论它们的变化特点；三、通过相同条件下圆弧面防波堤与半圆型防波堤两种堤型试验波浪力的比较，给出了圆弧面防波堤波浪力的近似方法；四、利用VOF法追踪自由水面，数值求解RANS方程，得到圆弧堤堤体周围的流场和压力场，初步分析了速度涡流与压力场的相互影响；五、对比数值分析与试验结果，探讨数值方法研究圆弧面防波堤水力特性的可行性，提供新的研究途径

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。