查询词典 numerical computation

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 control volume integration was applied to deduce the discrete expressions of the convection-diffusion equations. The staggered grid and SIMPLE algorithm were introduced to deal with coupling between pressure and velocity, and then the numerical computation expressions of such variables as fluid flow velocity and pressure were deduced. Using the backward difference method and incremental theory to discretize the governing equations for fields of chemical reaction, material structure and chemorheology, the numerical computation expressions of variables such as the monomer conversion, average molecular weight and fluid viscosity were constructed.

应用控制容积积分法导出了对流—扩散方程的离散表达式，引入交错网格技术与SIMPLE算法，实现了耦合的压力场与速度场的分离式求解，推导得到了流体的流动速度、压力等物理量的数值计算式；采用向后差分方法和增量方法，实现了化学反应场、材料结构场、化学流变场控制方程的离散，获得了反应转化率、聚合物平均相对分子质量、流体黏度等物理量的数值计算式。

Meanwhile, it could be seen that there does not exist a confidence interval with width less than 0.5 because of the property of Poisson distribution. Based on these conditions, the author mainly carried out research into two aspects of this problem as follows. Firstly, by numerical and theoretical analysis, the author compares some existent confidence intervals, for example,"exact" confidence interval, Wald confidence interval and Bayesian confidence interval, and finds some deficiencies points of the confidence intervals, whose modification version has been proposed .Also, several better confidence intervals such asare also presented .Secondly, for given confidence coefficient and interval width, the author constructs a class of asymptotical two-stage interval estimate procedures. At the same time, under varies restriction of confidence coefflcientent interval width, the optional sample size of the first stage has been computed by numerical computation. The numerical computation shows that the method considered in this dissertation have good properties and applied value.

同时，由于Poisson分布的特性，我们知道不存在其参数区间长度小于0.5的置信区间，基于这些情况，我们主要展开了以下两个方面的研究：一是利用数值计算分析与理论分析的方法对现有的若干置信区间如"精确"置信区间，Wald置信区间，Bayes置信区间等进行分析比较，发现了一些缺陷，针对这些缺陷，我们进行适当的修正，并得到几种性质较好的置信区间如：修正大样本区间Jeffreys原则下置信区间二是针对已给定的置信系数与区间长度，我们提出了一种渐近的两阶段区间估计程序，并利用数值计算的方法，在各种置信系数与区间长度限定下，算出了最优的第一阶段观测次数，大量数据表明，本文考虑的方法性态良好，具有应用价值。

In this thesis, the virtual boundary integral equation is based on double layer potential with the virtual density to be determined on virtual boundary. Since this integral equation related to double layer potential only involves the computation of the normal derivative and second normal derivative of fundamental solution, the exponential integral function is not involved in it, so numerical computation for the exponential integral function is avoid.

本文则基于双层位势，引入虚拟矩密度函数来建立虚边界积分方程，并首先对时间变量进行解析积分，在虚、实边界上采用常单元和等额配点离散，该方程只涉及含基本解的法向导数及其二阶法向导数项的计算，对时间变量进行解析积分后，不会出现对指数积分函数的空间变量的积分计算。

Then the basic fundamental and method of the computation of thermal load of the heated parts of internal-combustion engine are elaborated, the deflective differential equation of heat conduction, basic equation and boundary condition of the theory of thermo elasticity and numerical computation by FEA are introduced.

接着阐述了求解内燃机受热零部件热负荷的基本原理和方法，介绍了热传导的偏微分方程、热弹性理论的基本方程和边界条件确定的原则以及用有限元法进行的数值求解。

The research area involves computation of many optimization problems as well as many classical problems in numerical computation.

这方面研究不仅包括各种最优化问题的求解，也包括数值计算经典问题的求解。

Based on numerical computation, glass microfiuidic chips are fabricated, and experiments using microfluid fluorescence visualization technology are conducted to study sample electrophoresis transport characteristics in microchannel turns, with the aim to verify results of numerical computation.

在数值计算的基础上，制作了玻璃微流控电泳芯片，采用荧光可视化微流体实验技术，在微流控动态观测平台上实验研究了弯曲微通道中的样品电泳输运特性，验证了数值计算结果的正确性。

Based on them, distribution laws of subgrade temperature field under fluctuant boundary temperature cycle conditions are analyzed, and different ratios of slope for general subgrade and different status when there are or not banquettes are compared by laboratory simulation and numerical analysis; thermal insulation and cooling effect of thermal insulation slab, broken stone and non-power heat pipes is respectively investigated under the trend of elevated temperature by numerical analysis, laws of subgrade deformation are predicted under the trend of elevated temperature and influences of subgrade thaw settlement on pavement stress are studies by numerical computation for observation data of representative road sections selected.

为研究青藏公路冻土病害处治对策，从青藏公路2002年～2004年冻土病害整治工程实际出发，在系统分析研究青藏公路病害及发生机理的基础上，运用室内模拟试验、数值分析方法，依托处治冻土病害路段实际使用的隔热板路基、碎石路基、无动力热棒路基等进行现场试验，分析边界温度周期波动条件下的路基温度场分布规律，同时进行一般路基不同边坡坡率的对比研究及有无护坡道的对比研究；运用数值分析方法，对气温升高趋势下隔热板、碎石、无动力热棒的隔热降温效果进行了研究；选择代表性路段观测资料，运用数值计算的方法，进行升温趋势下的路基变形预测，研究路基融沉变形对路面应力的影响。

A comprehensive review and expectation about researching status in quo and development trends of viscous flow numerical simulation technique are given in this paper and grids generation methods, numerical computation methods, turbulent model and moving boundary simulation methods are the emphasis study in the paper. On the basic of above job a mathematical model of simulation turbulent flow with free surface is established and triumphantly applied to numerical computation on 2D spillway and 3D spillway with frusta of brake.

本文针对粘流场数值模拟技术的研究现状和发展动态作了比较全面的回顾与展望，重点研究了网格生成技术、数值求解技术、湍流模型技术和动边界模拟技术，在此基础上建立了模拟自由面湍流场的数学模型，并成功地应用到二维溢流坝和带闸墩的三维溢流坝过坝水流的数值计算。

Meanwhile , numerical computation of aerodynamics is widely applied with the progress of computer , large quantities of relative paper has been presented . but at present , the relative literature about turbulence characteristics of plural vehicles running in row and passing maneuvers is very limited . pointing to the above difficulty , in this paper , numerical computation of turbulent - velocity field is studied while a sedan exceeding a tractor - trailer truck

本论文在对某国产轿车单车外流场的模拟地面边界层、车轮转动和侧向风载荷研究基础上，以及两辆轿车并列行驶、同向超车的稳态研究的基础上，选取了两种笛卡尔网格方案和四面体混合网格方案，开展某国产轿车超过某大型运输车的数值模拟研究。

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。