On the other hand , the intensity moments method provides a useful approach to characterizing the laser beam quality . the main advantage of this approach is that the characteristic parameters of a laser beam at the output plane can be obtained easily from the initial parameters of the laser beam at the input plane 另一方面，强度矩方法是描述激光光束质量的重要方法，这种方法的主要优点是从入射面上光束的特征参数出发容易得到出射面上光束的特征参数，所以用强度矩方法描述激光的光束质量具有重要意义。
Based on the calculation of shearing - slipping failure probability of high arch dams , the calculation method and procedures are presented by use of the second moment method for calculation of the occurrence probability of the major failure modes of high arch dams , and the relation degree between the major failure modes and the failure probability with multi - failure modes of the high arch dam are calculated 以计算高拱坝剪滑溃坝发生概率为例，说明利用二阶矩法计算高拱坝各主要失效模式发生概率的步骤，进而求解各失效模式的相关程度及具有多个失效模式高拱坝的失效概率。
Moment method is used for the analysis of interference among the vehicular multiple antennae in this paper . the multiple antennae system is equivalent to a microwave network , then the admittance matrix of the network can be obtained . using the admittance matrix , we can analyze the characteristic of coupling between two antennae and the near field of the antennae by the mom 本文采用矩量法对车载多天线间的相互干扰特性进行了分析，将多天线系统等效为微波网络，然后采用矩量法求该网络的导纳矩阵y ，利用该导纳矩阵对天线间互耦特性进行分析，同时计算天线的近场分布。
In regard to nonlinear stochastic optimization in which the restraint function was nonlinearly expressed with stochastic parameters , the advanced first - order second - moment method was employed to study the structural optimization numerical model based on component reliability or failure pattern reliability and the method to transform the problem of stochastic optimization to that of certain determinate optimization 摘要针对约束函数被随机参数非线性表达的随机非线性优化问题，采用改进均值一次二阶矩法，研究基于元件可靠度或各失效模式可靠度的结构优化的数学模型，以及将随机优化问题化为确定性优化问题的方法。
First , the method of aperture integration - surface integration , which is based on physical optics theory , is used to study the radiating property of the 3 - d radome - enclosed antennas . secondly , the moment method is employed to analyze the electromagnetic radiation from radome - enclosed antennas with axi - symmetric revolving radome 然后应用矩量法针对具有回转体结构天线罩的带罩天线辐射进行分析，分析过程中利用回转体特点，采用适当的基函数将三维问题转化成二维问题解决，以降低计算量提高计算效率。
According to the nonlinear schr ? dinger equations , by which propagation of optic lattice soliton is governed , the moment method is applied to deduce the evolution equations of lattice soliton ’ s primary parameters . and conditions of formation and stable transmission of lattice soliton are found by further analysis 根据三阶非线性光学格子孤子传输所遵循的偏微分方程,利用矩方法推导出了格子孤子主要参量的演化方程,进一步分析得出了格子孤子的形成与稳定传输的条件。
Basic index and reliability principle of steel structure , and geometric significance are analyzed . the main computation methods , such as two order moment method , separation function and separation item coefficient , linear separation , and central point , check point , monte - carlo are presented . reliability analysis under relative variable , boundary determination ( single and double boundaries ) is analyzed 研究了钢结构可靠度基本原理、可靠指标的几何意义，分析了钢结构可靠度计算的一次二阶矩方法、分离函数和分项系数法、线性分离法，以及中心点法、验算点法、蒙特卡罗( monte - carlo )法，提出了变量相关情况下的结构可靠度分析方法、可靠度界限分析方法(单侧界限与双侧界限) ，基于极值分布的可靠度分析，并对钢结构动力可靠度分析方法进行了初步探讨。
The moment method is used to calculate the rcs of three - dimensional targets in this paper . these targets include conducting targets , dielectric targets and coat targets . triangular patches are used to model the surface of the target , then electric field integral equation ( efie ) and magnetic field integral equation ( mfie ) are built which satisfy the boundary conditions . the rwg vector base functions are used to denote equivalent electric current and magnetic current on the surface of the target . finally use the galerkin method ( rwg vector base functions are basis function and test function ) to transform integral equations into matrix equation . when obtain the equivalent electric current and magnetic current , we can calculate the scattering field and the rcs of the target 本文利用矩量法计算了三维导体目标、介质目标、涂层目标的雷达散射截面。首先采用三角形面元对物体表面几何形状进行模拟，然后建立满足边界条件的电场积分方程( efie )和磁场积分方程( mfie ) ，将物体表面的等效电磁流用rwg矢量基函数表示，最后利用伽略金法( rwg矢量基函数既作为基函数又作为检验函数)将电磁场积分方程转化为矩阵方程求解未知电磁流系数，得到了表面的等效电磁流后，可以计算散射场和目标的雷达散射截面。
Then the solving procedures of these bies by the rwg functions based moment method are elaborated , and the method of modeling complex objects built of arbitrary line , surface and volume structures is developed . in order to solve realize antenna and circuit problems , methods of adding excitations and concentrated loadings with moment method are deceloped , and matrix pencil ( mp ) method is used to deembeded the s prameters of antennas and circuits from the computed current distribution . some numerical results of practical complex antenna and scattering problems are presented to illustrate the veracity and effectiveness of the method 在第一部分中,首先从电磁场的基本理论出发,基于等效原理和边界条件以统一的方法建立了用于分析金属、介质及金属与介质混合结构的边界积分方程,并归纳和比较了各类积分的适用范围和优缺点;在此基础上,给出了使用基于rwg函数的矩量法求解各种边界积分方程的一般过程;研究了具有任意线、面、体组成的复杂结构的电磁建模方法,并给出了各种多面连接情况下基函数和未知量的选取方法;研究了使用矩量法分析电路、天线问题时集总元件和激励源的处理方法,并基于矩阵束方法( matrixpencilmethod )提取了电路和天线问题的s参数;最后通过分析一些工程中的复杂金属天线问题和具有“金属与介质混合结构”的散射和天线问题验证了方法的准确性和高效性。
Since complicated differential and integral operations were involved in the kernel of the integral equation , we simplified the equation and got the nakano equation . as instances , the planar archimedean spiral antenna , the planar equiangular spiral antenna , the monofilar helical antenna , the conical helical antenna with fixed ascending angle and the conical equiangular - spiral antenna were analyzed through the moment method . all of the results matched fairly well with the references and experiment results 这种方法的积分方程的积分核里含有复杂的微积分运算，为了简化计算，本文在推广的海伦积分方程的基础上，对方程进行了简化，推导了nakano方程，并以平面阿基米德螺旋天线，平面等角螺旋天线，轴向模圆柱螺旋天线，具有固定升角的圆锥螺旋天线和圆锥等角螺旋天线为例，用矩量法求解了天线上的电流分布，研究了螺旋天线辐射的宽频带特性，所得的结果均与参考文献吻合很好。
