数值方法

The developing process about establish the model of earth surface and several classical methods, which are the methods of radiative transfer, geometric optics, hybrids of two or more of these, and numerical simulation are discussed in detail.

较详细地论述了建立地物散射模型的发展情况和几种典型方法：辐射传输方法、几何光学方法、复合模型方法以及数值模拟方法等，初步研究了适用于植被、土壤、沙漠等环境背景的双向反射分布函数模型。

Firstly, the fully discrete standard finite element Galerkin method and the nonlinear finite element Galerkin method and the modified finite element Galerkin method in which time is discretized by the Euler implicit difference scheme are considered, and the - and - global relative errors and CPU time corresponding to the SG method, the NG method and the MNG method are computed respectively.

首先，对于全离散(时间离散是欧拉显式格式)标准有限元Galerkin方法和非线性有限元Galerkin方法以及修正有限元非线性Galerkin方法，分别进行数值计算，并比较了三种算法的计算解与精确解的误差估计及所耗费的CPU时间，结果验证了MNG方法要优于NG方法，而NG方法又优于SG方法。

The development and research progress of ground deformation induced by pipe jacking construction was reviewed in the paper.

对顶管施工引起的地面变形计算方法的发展概况及研究进展进行了分析，把地面变形计算方法归纳为现场监测方法、数值计算方法、理论方法和实例数据分析法，并进行了比较，以更好地指导工程施工。

Otherwise, we construct an exponential fitting schur product multistep method based on schur product multistep method and exponential fitting method.

数值实验表明，该方法与传统方法相比，在同等步长下，方法的计算精度远远高于传统方法。另外，本文将此类指数拟合方法与Schur积多步方法结合起来，构造了一类指数拟合Schur积多步方法。

In theory, firstly, the numerical simulation methods, such as the boundary element method, the finite difference method and the finite element method, were utilized to calculate the distribution of electric field intensity and potential of the electron-gun system, the focusing system and the whole equipment, respectively. Then, the trajectories of the electron-beam were traced by using of the Runge-Kutta method and the Monte-Carlo method associatively. The point spread function was also calculated.

在理论分析中，先后采用边界元方法、差分方法、有限元方法等科学数值计算方法，编制程序，对X射线源的电子枪发射系统、聚焦系统以及发射系统与聚焦系统的组合系统等的电场分布进行了严格的计算，在准确求得各系统电场内各个剖分点的电场场强、偏导数等参量的基础上，采用蒙特-卡罗模拟方法和不等距龙格-库塔方法相结合，追踪由LaB_6单晶阴极表面发射出的大量电子束在电场内的运动轨迹，求出点扩展函数，并根据点扩展函数的优劣，反复调节、大量计算对比，挑选出X射线源最佳的电极结构及其组合。

With the support of a major research grant of Zhejiang Province (No. 001101027) and the Plan of Promoting Education of Excellence of Zhejiang University in the 21st Century, this dissertation is devoted to address the above problems and fabricate an L-band EDFA with low cost, high performance and technological innovation.First the mechanism of an erbium doped fiber amplifier is introduced. Various theoretical models based on classical rate propagation equations are summarized and compared for their applications. We use a modified numerical model based on the Giles model, which agrees with the experimental results well. This serves as the theoretical base for the whole thesis and will be used to optimize the characteristics of EDFAs. A novel method based on a map of noise figure and gain is proposed to analyze efficiently the dependence of the noise figure and gain for EDFAs on the EDF length and the pump power. The characteristics of various EDFAs are studied and compared.Secondly, some important parameters are introduced to describe the characteristics of EDFAs. The methods and the experimental setups for measuring the gain and noise figure of an EDFA are emphasized. We introduce how to measure the characteristics of each component of an EDFA, especially the gain and absorption coefficient of an erbium doped fiber.Thirdly, four types of simple and novel L-band EDFA structures with low noise, high gain and low gain ripple are proposed to satisfy the requirement of a DWDM system. They can be classified into two categories. In the first category, a single ASE pumping is served asa secondary pump. This category includes the following three types. Type: a new construction using a fiber Bragg grating in an unpumped EDF section at the input side. Type: a new structure of L-Band EDFA with two-stage pumps, which utilizes the forward ASE as a second pump.

本论文本着科技创新、服务于生产实践的精神，以设计价格低廉，性能优越、结构合理简单的L-band EDFA为目标，依托浙江省科技厅重大科学基金资助项目(001101027)和浙江大学振兴教育计划资助的全光网络的搭建—《光通信技术》课程实验建设项目，展开了如下工作：首先，介绍了掺铒光纤放大器的工作原理，归纳总结了基于速率方程基础的EDFA的各种理论模型，分析比较了各个模型的特点和适用场合，最终选择完善的Giles理论模型作为本论文分析设计EDFA的理论基础；针对实际实验条件提出了修正的EDFA模型的数值计算方法；创新地提出了增益—噪声系数全局分析法，直观有效地分析了EDFA的增益和噪声系数与掺铒光纤长度和泵浦功率的依赖关系，并对各种EDFA的性能作了全面的比较；第二，介绍了掺铒光纤放大器特性参数的定义与测量方法，重点介绍了噪声系数和增益系数的测量方法及实验装置；介绍了组成掺铒光纤放大器各组件的特性测量方法，重点介绍了测量掺铒光纤参数的方法和实验装置；第三，针对WDM系统对L-band EDFA谱平坦、低噪声、高增益的要求，我们创新地提出了四种不同的L-band EDFA结构，按设计思路可以分为两大类：一类是基于单抽运二级泵浦法，这一类包括在未泵浦掺铒光纤的输入端插入一根布拉格光纤光栅的两段L-band的EDFA的新结构；基于前向ASE光作为二级泵浦源推动下一级EDF工作的泵浦分配、两段级联L-band的EDFA的新结构；基于单根光纤光栅、泵浦分配、两段级联的EDFA；另一类则是基于同时应用前后向C-band ASE作二级泵浦源的双抽运法，如基于前后向ASE光作为二级泵浦源的三段级联L-band的EDFA的新结构。

Secondly, conception of vortex board was introduced, the numerical simulation was implemented on vortex tube, numerical simulation method was verified of valid by compared with experiment results.

其次，引入涡流板概念，对涡流管进行数值模拟，对比数值模拟和试验结果，验证了数值模拟方法的可靠性。

This text aims at the difference of several representative geology conditions in Yang Shui mining area, carried on the primary election to the mining method of Yang Shui mining area, introduced the new theories of numerical optimization choice of mining method that are fuzzy mathematics and artificial neural network etc, based on the existing mining methods that are feasible, adopt the fuzzy optimization choice principle of flexible neural networks, and synthesize several experts and fieldworkers' opinion, built up the related mathematical model and revised model, carried on processing of programming through computer, thus established each optimization mining project under several representative geology conditions in Yang Shui mining area, and carried on optimizing to the existent unreasonable parameter in mining project;have the great significance to aim at each kind of geology condition for each mining area to adjust the mining method in time in the course of mining, abandon chronically unreasonable mining method, full reclaim the mine's resource, lower the dilution rate、 loss rate of mineral mining, raise the production capacity of stope and economic benefit of mine.

本文针对洋水矿区几种典型地质条件差异，对洋水矿区采矿方法进行了初选，介绍了模糊数学和人工神经网络等采矿方法数值优选新理论，在现有可行性采矿方法的基础上，采用弹性神经网络模糊优选原理，并综合多位专家及现场工作者的意见，建立了相关的数学模型及修正模型，通过计算机进行编程处理，从而确立了洋水矿区几种典型地质条件下各自的最优采矿方案，并针对采矿方案中存在的不合理参数进行了优化，为各矿区针对各类地质条件在采矿过程中及时调整采矿方法，摈弃习惯性的不合理采矿方法，充分回收矿山资源、降低矿石开采的贫化率、损失率，提高采场生产能力以及矿山经济效益具有重大意义。

The comparison of the computational results of real gas model with that of perfect gas model shows that it is very important to apply the real gas model in the numerical simulations, and also the real gas model presented shows itself more profitable and applicable in numerical applications.

对单列叶栅和透平级内复杂三维凝结流动的数值计算方法进行了研究，结合欧拉/欧拉型自发凝结数值模型，以FLUENT软件N-S求解器为平台，建立了适合工程实际应用和复杂条件下非平衡凝结流动的数值计算系统。

A three dimensional Navier Stokes equation is solved with a standard k ε turbulent model. Two experiments were carried out and the total pressure of jet flow was tested. Based on the tests, the differences between the calculated and test results were found to be 3% and 7% respectively. It proved that the results of calculation can well be used in engin...

研究采用数值计算和试验测量相结合的方法，控制方程为三维、雷诺平均 Navier- Stokes方程及 k-ε二方程的紊流模型，并且对该发动机进行了燃气流场的测试，对流场中的总压强进行了直接测量，进行了两次试验；在两次测点位置，试验结果与数值计算值相差分别为 3%和 7%；证明了对双喷管火箭燃气射流流场的数值计算具有了较好的精度，计算模拟结果可以用于工程设计中

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。