数值方程

In this paper, we contribute an evolutionary heterogeneous beliefs model byusing t distribution to replace traditional standard normal to describe fundamen-tal price process and adding risk-adjusted market fraction function in classicaltwo types traders scheme. And then we utilizedifference equation stability and bifurcation theory and numerical simulation tostudy the system. It is found that the system has some styled facts (high kurto-sis、fat tali and long memory) of the actual financial market, and this indicatesthat the simulation model can reflect well the true financial market.

本文通过引入t分布代替原有的正态分布描述基础价格过程，引入经风险调整的投资者市场分数维函数取代原有的无风险调整的市场分数维函数，在经典的两类投资者(自主投资者和图表分析者)模拟模型框架下，建立了新的异质预期资产定价模型，利用差分方程稳定性和分支理论及数值模拟的方法对该系统进行理论分析和实证研究，发现模型具有真实金融市场的程式化事实(尖峰厚尾性，长记忆性等)，模拟效果较好。

The evaluation method and physics meaning of every parameter in the viscosity relationship equation were elaborated using theologic experiment data, and the viscosity relationship equation be referred to in the literature were appraised using simulate data and experiment data.

利用聚甲基丙烯酸甲酯乳胶体系的流变数据，阐述该粘度关系方程式中各参数的求值方法及其物理含义。同时也用数值模拟数据以及实验数据，评价了文献中所提到的粘度方程。

By analyzing the heat transfer process in trombe wall and of air gap, a CFD model for simulating temperature field in trombe wall is presented and solved by coupling the conductive and radiative heat transfer in solid with RNG k-ε equation.

对特朗勃壁内传热过程和夹层空气动力进行分析，建立了CFD数值模拟模型，耦合流固传热，利用Relieble k-ε两方程模型模拟了特朗勃壁内温度场。

A continuum model integrated with heat, mass, momentum transport behavior is applied to simulation of solidification process of continuous casting billets, and the effects of undercool degree on simulation are considered in particularly.

将连铸坯凝固过程三个区（固相区、固液两相区、液相区）的三个场的定量描述统一在同一组微分方程中，实现了连铸坯凝固过程温度场、流场和溶质场的数值模拟。

Based on the fully implicit unfactored method, a numerical solution of three-dimensional unsteady Reynolds-averaged Navier-stokes equations is presented, in which the revised Baldwin- Lomax turbulent model is employed.

基于全隐式无分裂方法，数值求解三维非定常雷诺平均的Navier-Stokes方程，紊流模型采用修正的B-L代数模型。

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。

Viscous flows around an infinite span untapered swept back wing at high angles of attack are investigated numerically by solving the quasi two dimensional Navier Stokes equations to deal with the effects of the swept-angle on the flow structure and force behavior.

通过数值求解Navier Stokes方程，研究了无限翼展直后掠翼在不同后掠角下的大迎角粘性分离流，探讨了后掠角对流场结构和升阻力特性的影响。

Only an arbitrary single pulse among pulse train with temporal separation of about 1 ps was trapped by soliton pulse,the trapped pulse was blue-shifted and the optical spectra of trapped pulse was distinctly separated from those of the untrapped signal pulses.The trapped pulse can be easily picked off using a wavelength filter such as a fiber Bragg grating.

通过数值求解光子晶体光纤中脉冲传播满足的耦合非线性薛定谔方程，发现用孤子脉冲可俘获信号脉冲串中的任何一个脉冲，被俘获的信号脉冲的中心波长明显蓝移，在频域上和其他信号脉冲分离开来，于是让信号脉冲串在输出端通过布喇格光纤光栅，被俘获的信号脉冲将被过滤掉。

This paper studies numerically the influence of the tip clearance on the three-dimensional viscous flowfield and performance of the NASA Low-Speed Centrifugal Compressor impeller with a vaneless diffuser. A three-dimensional viscous code developed by the authors is applied with several acceleration methods: local time-step, multigrid and residual smoothing.

通过求解N-S方程，数值研究了叶顶间隙对NASA低速大尺度离心压缩机三维粘性流场及气动性能的影响，在计算程序中采用了当地时间步长、多重网格以及隐式参差光顺来进行加速。

This paper puts forward an improved Curtice model, by modify drain-source current I ds and breakout volage V p of GaAs MESFET tube on the basis of Curtice semiexpirical model, and uses fast simulated annealing algorithm to resolve it.

从模型的建立方法来看，现有GaAsMESFET非线性模型大致分为 3种类型：(1)最值模型[1] 这种模型从求解GaAsMESFET的二维或三维电磁场方程出发，用数值计算算出MESFET的非线性特性。

But we don't care about Battlegrounds.

但我们并不在乎沙场中的显露。

Ah! don't mention it, the butcher's shop is a horror.

啊！不用提了。提到肉，真是糟透了。