查询词典 numerical constant

As important ways for numerical solutions of partial differential equations, spectral methods have been developed rapidly in the past several decades. They not only have been widely applied to numerical simulations in various fields such as physics, mechanics, aerology, oceanics etc, and their theories of numerical analysis also tend to perfect.

作为数值求解的一种手段，谱方法在近几十年得到了蓬勃的发展，它不仅被广泛运用于物理、力学、大气、海洋等领域的数值计算，而且它的数值分析理论也不断地趋于完善。

The company produces the processing equipment to be advanced, check-out facility excellent, has the numerical control lathe, the numerical control drilling machine, the machining center, the numerical control gear-hobbing machine, the gear shaper, the fine borer, the universal milling machines, each kind of grinder, the table planer, the booklet bender, the large-scale lathe, the mechanical slicer, high intermediate frequency quenching, the well type, the box-type hardening furnace, the tempering furnace, the automatic welding machine, the X-ray crack detection machine, the cloth, the Rockwell tester; Electric hoist test platform, sound-level meter, varnish film thickness gauge, altazimuth, level; The material analysis laboratory, the metallography analysis room and so on full had guaranteed strictly the vehicle, the mill, dig, rub, pull, the boring, to drill, the ramming, cutting, the angle iron, the chemical examination and the heat treatment and so on complete technical process.

公司生产加工设备先进，检测设备精良，拥有数控车床、数控钻床、加工中心、数控滚齿机、插齿机、精密镗床、万能铣床、各种磨床、龙门刨床、折弯机、大型车床、刨床、高中频淬火、井式、箱式淬火炉、回火炉、自动焊机、 X射线探伤机、布、洛氏硬度计；电动葫芦试验台、声级计、漆膜测厚仪、经纬仪、水准仪；材料分析化验室，金相分析室等充分严格保证了车、铣、刨、磨、拉、镗、钻、冲压、切割、弯板、化验及热处理等全部工艺流程。

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 unique advantage of this halfanalytical numerical method is that the analytical process of Conformal Mapping can transform an irregular area into a regular one such as a rectangle. Therefore, the discretization error of numerical methods on the boundary can be avoided, and the numerical algorithm can be implemented more easily, with the computing efficiency improved.

这种保角变换的半解析数值方法的突出优点是：利用前期的保角变换解析处理将不规则的场域转化为规则的矩形域，从而避免了纯数值技术对复杂边界的离散化误差，降低了后期数值计算的算法复杂度，并提高了计算效率。

Considering complicated conditions of the coastal dynamic environment, sediment dynamics, and together with the immature sediment itself, the predicted results will be somewhat limited if only with numerical model. So, in order to obtain microcosmic quantitative assessment and macroscopically understanding, numerical model is combined with field observations in the thesis. Firstly, the tidal current, SSC distribution, benthal deposited materials were basically analyzed by field observations. Then, the tidal current, SSC distribution, and the erosion and accumulation of the seabed were simulated with the numerical model of ECOMSED.

但由于海岸动力环境多变，泥沙运动复杂，加之泥沙问题本身的复杂性，如仅用数学模型，其预测结果将受到一定的限制，故本文采用实测调查与数学模型计算相结合的方法，宏观把握，微观量化，在掌握岚山港西突堤工程所在海域潮流、悬沙量分布、表层底质沉积物类型及特点基本态势的基础上，紧扣开发工程可能引起潮流场变化，分析工程后悬沙量、海底冲淤变化及其空间分布，进而建立潮流作用下的泥沙输运数学模型，首先比较好地模拟目前岚山港西突堤工程附近海域的潮流场和悬沙场，然后预测海湾沿岸可能引起的冲淤强度变化和冲淤区域的空间分布。

The proposed method has the merit that the numerical characteristics of stochastic temperature field response can be obtained by analyzing the random temperature field just in one time.3. Perturbed numerical algorithm of nonprobabilistic convex set theoretical models on the temperature fieldThe uncertain parameters of physical parameters and initial boundary conditions of heat conduction are described by the convex model. The perturbation formulas of the upper and lower bounds of temperature field response with unknown-but-bounded parameters are given via the combination of matrix perturbation theory and the convex set theory model.4. Numerical analysis for transient temperature field with interval parametersConsidering the uncertainties of the transient heat transfer, the physical parameters and initial boundary conditions are regarded as interval variables.

该方法具有只进行一次随机温度场分析便可以获得其响应的数字特征的优点。3、温度场的非概率凸集合理论模型的摄动数值解法将结构导热的物理参数、温度场的初始和边界条件等不确定性参数以凸模型加以描述，基于矩阵摄动理论和处理不确定问题的凸集合理论模型的结合，导出有界不确定参数瞬态温度场响应所在集合的上、下界摄动计算公式。4、具有区间参数的瞬态温度场数值分析考虑结构瞬态热传导问题的不确定性，将结构各物理参数和温度的初、边值条件均视为区间变量。

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 addition, depending on the method of numerical simulation and theoretical analyses, some kinematic and geometric features of 0° involute—enveloping worm gear drive, such as meshing surface, first—type limit, second —type limit, worm surface, the numerical representation of contact line and bearing contact, are systematically studied. These relevant conclusions provide an important basis for the design and manufacture of new type worm gear set. As we predict, the method of numerical simulation has special effect in solving the question of complex conjugate surface.

综合利用仿真方法与解析手段，对0°渐开线包络蜗杆传动的啮合面、一类界限、蜗杆齿面构成、仿真接触线及仿真接触域等运动几何学特性进行了系统研究，有关结论为此种新型蜗杆副的设计与加工提供了重要基础，并且显示出数字仿真方法在研究复杂共轭曲面问题时所具有的特殊功效。

A simulation-based numerical analysis method of EDD scheme, which is proposed in this thesis, can solve this problem successfully. The consistence between numerical analysis and simulation result strongly proves that the proposed numerical analysis method is correct.

本文提出了一种"基于计算机仿真的各优先级业务信元时延分布"数值分析方法，与计算机仿真结果的基本吻合证明了此方法的正确性。

Numerical control technology to go on technology that control with digital information to mechanical movement and working course, numerical control equipment whether represented by technology of numerical control new technology make industry and new developing infiltration electromechanics integrated product that form of manufacturing industry to tradition, i.e.

数控技术是用数字信息对机械运动和工作过程进行控制的技术，数控装备是以数控技术为代表的新技术对传统制造产业和新兴制造业的渗透形成的机电一体化产品，即所谓的数字化装备，其技术范围覆盖很多领域：(1)机械制造技术；(2)信息处理、加工、传输技术；(3)自动控制技术；(4)伺服驱动技术；(5)传感器技术；(6)软件技术等。

The dissecting of samples in group2 were difficult. The root of pulmonary artery and ascending aorta failed to be unfolded because fibrous tissue was tough, right and left fibrous trigone were too firm to be solved by hand. Cardiac muscle fibers couldn't be stripped along myofibrillar trajectory since they were prone to break because of their friability.

组2的心脏解剖困难，表现为纤维组织坚韧，游离肺动脉非常困难；徒手无法松解左、右纤维三角，肺动脉和主动脉根部的游离非常困难；心肌纤维坚硬、质脆，解剖时容易断离成碎块，无法沿纤维走行方向剥离。

We have battled against the odds in a province that has become increasingly violent.

我们对在一个争夺日益激烈省的可能性。