查询词典 numerical method

This thesis contributed to the comprehensive study of the Finite-Difference Time-Domain method and its application to the numerical computation of radiated electromagnetic fields in switched mode power supplies. The work includes mainly three parts: the study on the performance of PML absorbing boundary condition applied to pseudo low frequency electromagnetic problems; the validation of the FDTD method with PML absorbing boundary conditions and the corresponding computer software based on the numerical study of the electromagnetic field of an electric dipole antenna, and its application to the numerical computation of radiated electromagnetic fields in switched mode power supplies; the development of an improved alternating direction implicit finite-difference time-domain method.

在综合前人工作基础上，本文对时域有限差分法及其在开关电源辐射电磁场数值计算中的应用进行了系统的分析和研究，其核心内容包括：伪低频电磁场数值计算中PML吸收边界条件性能的研究；基于基准问题—电偶极子天线三维辐射电磁场，验证了本文构造的基于PML吸收边界条件的三维FDTD法及其计算软件，并应用于高频开关电源辐射电磁场的数值分析；提出了一种改进的交替方向隐格式时域有限差分法。

The main contents of this course include: introduction, extraction of root from an equation, numerical solution of a system of linear equations, interpolation method, the method of fitting of a curve, numerical integration and differentiation, numerical solution of a differential equation, one-dimensional search method of extreme value problem, etc.

本课程包括以下内容：绪论、方程求根、线性方程组数值解法、插值法、曲线拟合法、数值积分与数值微分、微分方程数值解法、极值问题的一维搜索法。

Second order incident boundary condition on fixed incident boundary is derived for numerical simulations, based on the cnoidal or sinusoidal motions of wave maker paddle, which shows that the prediction with second order incident boundary condition is more accurate than the prediction with first order incident boundary condition. 2 The analytical solution for higher-order Boussinesq equations is derived and its applicable range is discussed. 3 A 2-D fully non-linear numerical model using boundary element method is developed to obtain wave forces acting on rectangular obstacle. 4 The three-dimensional fully non-linear waves are studied in a numerical wave tank using finite element method.The studies on the coupled numerical model combined Boussinesq equations with Laplace equation are following.

非耦合非线性波浪计算模型：1 根据造波板做椭圆余弦运动或正弦运动速度，推导出数值模拟波浪水槽时固定入射边界上的二阶波浪入射边界条件，数值计算结果和实验结果的对比表明采用二阶入射边界条件对波面升高的预报比采用一阶入射边界条件对波面升高的预报更为精确；2 推导了波浪水槽造波板做正弦运动所产生波浪的高阶Boussinesq方程摄动展开解析解，讨论了该解析解的适用范围；3 对整个波浪水槽应用边界元方法数值模拟了波浪对物体的非线性作用；4 用有限元法求解三维Laplace方程模拟了三维完全非线性波浪水槽。

This thesis is divided into six parts. The first chapter is preface, the current status of research in the inverse problems for parabolic partial differential equations is reported; the second chapter is "regularization methods for numerical differentiation and their applications ", in this chapter we investigate many regularization methods from a viewpoint of regularization theory and algorithm, some applications in the inverse problems for parabolic partial differential equations are given; the third chapter is "spectral regularization methods". Based on Fourier analysis, within the framework of regularization theory, we apply the spectral methods to some ill-posed problems. Many numerical experiments are done in order to show the validity of the methods; the fourth chapter is devoted to wavelet dual least squares method and a revised wavelet method; in the fifth chapter,we combine finite difference method with method of lines and apply it to the backward heat conduction problem in time; in the sixth chapter "identification problems for unknown source ", the essence and the degree of two problems related to source identification are pointed out, at the same time, some numerical methods are reported.

本文分为六个部分，第一章前言简要分析了国内外抛物型偏微分方程反问题的研究现状；第二章数值微分的正则化及其应用从正则化理论和算法的角度出发，考察了许多正则化方法，还给出了数值微分在抛物型偏微分方程反问题的一些应用；第三章谱正则化方法是在Fourier分析的基础上，在一般正则化理论的框架下，给出了这种方法在各种不适定问题中的应用，数值实验表明谱方法是有效的；第四章研究了小波对偶最小二乘方法和改进的小波方法；第五章主要研究了有限差分方法结合线方法在时间反向热传导问题中的应用；第六章是未知源识别问题，主要指出了两类未知源问题的不适定程度和不适定本质，同时报告了一些数值方法。

The objective of this study is aimed at the implementation of parallelized numerical quadrature routines. The algorithm we choose for numerical quadrature routines is the so called "Adaptive Romberg Tree integration scheme"(abbr."ARTint") proposed by Lin et. al.[1997]. This numerical quadrature scheme can arrange the function evaluation points adaptively in accordance with characteristic of the trend of variation in integrand function values. When the accuracy of the numerical quadrature value is requested to be increased, a newer and larger set of function evaluation points must be incurred. The main advantage of ARTint method is the inclusion of all function evaluation points used in previous stages. It is this feature of ARTint method that makes it a quadratue scheme with prominent computation efficiency.

本研究在探讨数值积分程式之平行化，所使用的演算法为林聪悟与林佳慧[1997]一书所提出的「Romberg树自动布点数值积分」架构，此一数值积分方法能以适应被积函数值变化情形方式自动安排积分点来进行数值求积计算，在提高阶数以获得更高精度积分值的过程中，此一方法只须再计算新增加积分点的函数值，搭配先前已计算过的函数值的重覆运用即可获得更精确的数值积分估计值，如此将能减少升阶过程中函数求值计算的次数，有效率地完成单重积分的数值计算。

The classical cutting stock algorithm——column generation technology , and wrap up rectangle technology for abnormity are analyzed ; The development of AutoCAD with ObjectARX is studied and the generating method of cutting outline drawing and layout drawing were found out on the basis of analyses of the graph database structure of AutoCAD and the basic operation of it ; The process planning technology of plate material cutting orienting numerical control is studied a process planning method directly based on layout drawing is established ; The emulation technology in AutoCAD is studied and a kind of dynamic emulation method is put forward , which is realized by incrementally modifying graph entity ; The postposition of NC program of the integrated cutting system constructed on software plug-in is proposed , which can effectively solve the problem that it is difficult for a numerical control programming system to be common , which is caused by the difference of instruction format and control parameter between different type of numerical control machine .

分析了经典的矩形件优化排样算法——列生成法和针对异形件的矩形包络算法；研究了基于ObjectARX 的AutoCAD 开发技术，结合对AutoCAD 图形数据库结构及其基本操作的分析，给出了下料轮廓图和排样图的生成方法；研究了板材数控下料加工的工艺处理技术，建立了一种直接基于排样图进行的图形交互工艺规划方法；研究了在AutoCAD环境中的板材下料数控仿真技术，给出一种通过增量修改图形实体对象实现的动态仿真方法；提出以软插件技术构建集成下料系统的数控编程后置处理部分，能够有效解决因数控下料机床指令格式及控制参数不统一导致的自动编程软件系统不易实现通用性的问题。

In this thesis, I summarize the theoretical calculation method, applied scope and notice of siphonic drainage system, and point out the advantage of siphonic drainage system compared with gravitation drainage system. In the archetype experiment study of siphonic drainage tube, I adopt different tube diameter and different structural height to survey the drainage volume and press in different place. I observe various kinds of flow state, and get chief factors which influence hydraulic peculiarity of system as the tube diameter or structural height, and find out the relevance of factor to flux. I apply CFD Fluent software and adopt standard k-ε model and RNG k-ε model, then use finite volume method and second-order upwind scheme to discrete numerical model, while coupling numeration of velocity field and press is based on SIMPLE. In the numerical simulation of curved part of tube, siphonic drainage tube experiment system and multi-outlet siphonic drainage system, I make research on internal velocity and press of system in different project condition by changing the tube diameter of curved part, negative press value in tube export and improving the quantity of water gutter. This thesis first adopts a method of combining archetype experiment and numerical simulation to study the siphonic drainage system, test and verify the validity of experiment and numerical simulation, and makefurther study on system, it solves the problems of limited testing conditions, and has a logical results, it can provide a valid method for optimizing and designing the drainage tube-net system. The conclusion have referring value for study and design of siphonic drainage system.

本文首先对虹吸式排水系统理论计算方法、适用范围以及注意事项做出总结，并分析了虹吸式排水系统的优势；再对虹吸式排水管道进行原型试验研究，采用不同管径不同立管高度，对系统流量、管道压强进行量测，观察了各种工况下的流态，对其水力特性进行研究分析，找出影响水力特性的落差、管径主要因素以及与排水量的关系；进一步应用计算流体力学Fluent软件，采用标准κ-ε模型与RNGκ-ε模型，计算过程应用有限体积法和二阶迎风格式对数值模型进行离散，速度和压力的耦合采用SIMPLE算法，分别对系统弯管段、虹吸排水管道试验系统、多斗虹吸式排水系统进行数值模拟分析，通过改变管段弯头处半径、管段出口负压值、增加雨水斗数对不同工况下系统内部的速度和压力进行研究；本文首次采用结合原型试验与数值模拟相结合的方法，对虹吸式屋面雨水排水系统进行研究，试验与模拟相互验证，并进行拓展，很好地解决了虹吸式屋面雨水排水系统由于试验条件限制问题，结果正确合理，为排水管网系统设计和优化研究提供了有效的方法，对工程设计有较好的参考价值。

Corresponding energy and chemical potential are also worked out by numerical method.

并且，通过数值模拟我们计算了不同原子数的能量和化学势。

The numerical method based on the wave approach is presented for the dynamic response analysis of high-rise structure by applying Timoshenko beam theory.

目的 提出高层结构动力响应的波动分析方法。

This paper reviews and summarizes the progress in this field as follows: the mathematical model and the difficulty of the analytical solutions is introduced; discusses the latest progress of the numerical solutions is discussed; the finite difference method, the Godunov method, the Boltzmann method, and the KFVS method of one-dimensional dam-break problem are introduced; the TVD method, the discontinuous finite element method, the finite volume method and characteristic method of two-dimensional dam-break problem are discussed; the applicability, the advantage and the disadvantage of each method are analyzed; and the progress in the numerical calculations of flow of fluid with free surface are presented.

回顾和总结了国内外对溃坝水流演进问题的研究进展：介绍了溃坝水流的数学模型及解析解法存在的困难，进而讨论了数值解法的最新进展；论述了求解溃坝水流一维问题的有限差分法、近似黎曼解的Godunov格式法、Boltzmann法、KFVS法和二维问题的TVD格式法、间断有限元法、有限体积法、特征线法，并分析了各种方法的适用范围和优缺点，及讨论了限制函数的使用；介绍了利用自由水面追踪方法计算溃坝水流的研究进展，并根据目前存在的不足和实际工程的需要，提出了进一步研究的方向和发展趋势。

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。