数值方程

Based on GIS and water pollution model, the paper discusses sulfured pollution in Yellow River, analyses diffusion equation of sulfured pollution, implements visible presentation, provides a new method for water pollution control and management.

本文以黄河某河段的硫化物污染为例，基于GIS技术和水环境数值模拟方程，研究污染物在水环境中的运移扩散规律，并实现污染物扩散的可视化表达，探索污染控制和治理的新方法。

All these work are finished above the study of abundant interrelated literatures.b Two-dimensional Poisson equation is solved by both Chebyshev Tau method and Chebyshev Galerkin method, the numerical uncoils are compared with the exact one.

对于二维Poisson方程边值问题，本文分别推导了Chebyshev Tau方法和Chebyshev Galerkin方法的计算公式，实现了相应的数值模拟。

In this paper, we consider numerical simulation of some kinds of evolution equations.

本文讨论了几类发展方程的数值模拟。

Based on the 3D time-average Navier-Stokes equations, k-ε model was used to simulate the 3D turbulent flow field of whole flow passage in the Francis turbine including guide wickets, runner and draft tube. The energy performance and cavitation performance were predicted from the simulation results, and the calculated data were compared with the results of hydraulic turbine model experiment. The calculation of turbine efficiency and the measured efficiency was very closed and the maximal relative error was 0.9%.

该文基于Navier-Stokes方程和k-ε紊流模型，采用贴体坐标和交错网格系统，用SIMPLEC算法对一模型混流式水轮机引水元件、转轮和尾水管进行了联合计算与转轮单流道计算，数值模拟了水轮机各通流元件内部三维湍流流场，预测了水轮机的能量性能和空化性能，并与水轮机模型试验结果进行了对比。

In the field work using the Control Source Audio-frequency Magnetotelluric method, the space between the transmitter and the receivers is up to several kilometers. In order to study the effect of the anomalous body locating at between the transmitter and the receivers, we simulate the CSAMT response using 3D Contraction Integral Equation method.

在可控源音频大地电磁法野外作业中，源和勘探区间的距离可达几公里，为了了解源和勘探区间的异常体对勘探区内异常响应的影响，我们用三维压缩积分方程法做了数值模拟研究。

To match the boundary conditions, the modified Bessel functions are expanded to the planar wave in the interface. Then the eigenvalue equations of different polarizations are obtained by scalar approximation. At last, the relations between propagation losses and the states of polarizations, the geometric structures of the fiber, the refractive index and thickness of the polymer are calculated.

论文首先给出其等效折射率数学模型，在纤芯和包层中，光场用贝塞尔函数及虚宗量贝塞尔函数的求和表示，在聚合物和金属中用指数函数的求和表示，交界面上采用将虚宗量贝塞尔函数用平面波展开的方法匹配边界条件，然后利用标量近似求出极化D型光纤不同偏振态光场模式的本征值方程，最后通过数值计算得到光纤的传输损耗与抛磨平面和纤芯之间的距离，聚合物粘接材料的折射率和厚度，以及偏振态之间的关系。

Kinematics and dynamics modeling and analyzing method of a 3-RRRT parallel robot was studied. Kinematic model of the 3-RRRT parallel robot was set up with both the branch bar's relative coordinates and movable platform's absolute coordinates used as it's generalized coordinates. On the base of Kane's equation, dynamics model of the 3-RRRT parallel robot was built. Dynamic Numerical simulation of the 3-RRRT parallel robot was finished by using Matlab software, and so it provides valuable reference for motion control strategy of the 3-RRRT parallel robot.

研究一种3-RRRT新型高速搬运机器人运动学与动力学建模及分析方法，以支链构件相对运动坐标和动平台绝对运动坐标作为广义坐标，建立了3-RRRT型并联机器人的运动学模型，结合带乘子的凯恩方程建立了3-RRRT型并联机器人的动力学模型，并利用Matlab软件平台进行了动力学数值仿真，进而为3-RRRT型并联机器人的控制策略研究提供参考。

The principle of interaction between rail and bridge has been reasoned, the mechanism of the formation of longitudinal additional forces including braking force, bending force and temperature ...

文中深入探讨了线桥相互作用原理，论述各种纵向力的产生机理及其求解方法，对传统的微分方程解法及现代的数值解法进行了分析与对比。

The plastic deformation mechanism of the process is explained. The vector equations of the curved conical surface and the figure of the particle motion for the forming process of the bending tube are presented. The theoretical model of stress and strain fields of the forming process is deduced. The practical forming process of tubes of large diameter demonstrates the validity of the new type of design method of the ox-horned core bar and the computation formula of the length of the raw tube.

本文通过研究弯管成形瞬时应力、应变状态及演化过程，阐明了弯管成形过程受力变形特点及力学原理；提出了一种适合弯管变形分析的新单元及数值方法；建立了弯管成形过程应力、应变场&标准图象&；通过研究弯管成形过程金属流动规律及力学条件，阐明了本工艺塑性变形机理；建立了描述弯管成形过程的曲锥面向量方程及其质点运动学图象；推导了弯管成形过程应力、应变场理论模型；结合大口径弯管生产过程，验证了本文给出的新型牛角芯棒设计方法和管坯长度计算公式的正确性。

Firstly the elastic stage of the cutting tool and workpiece in rectangular element is modeled and the relationship between the element node force and element node displacement also deduced.

首先选用矩形单元对刀具和工件弹性阶段进行有限元建模，得出其单元节点力和节点位移之间的关系，然后利用普朗特路斯方程，推导工件材料塑性变形时单元节点力和节点位移之间的关系，并指出金属由弹性变形到塑性变形时其单元刚度矩阵变化的规律，从而为实现金属切削过程的数值模拟提供可靠的理论基础。

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。