查询词典 difference equation

Starting from the quantum hydrodynamic equation of electron and photon kinetic equation, photon Landau damping is discussed.

从电子的量子流体动力学方程和动理学描述下的光子运动方程出发，研究量子效应对光子朗道阻尼的修正。

It also make students grasp building method and analyzing method of some important mathematical model (such as wave equation,Laplace equation).

使学生熟悉一些重要的电磁场问题的数学模型（如波动方程、拉氏方程等）的建立过程以及分析方法。

Based on second-order Laplace equation and boundary condition, obtains the integral equation after Green transformation.

基于二维Laplace方程和边界条件，经过Green转换得到以势函数及势函数法向导数为未知量的积分方程。

First,the knowledge of mechanics and electromagnetics was applied to build the equilibrium equation of thick-walled cylinders'structures,and a solvable equation was obtained utilizing the Laplace transforms and the Hankel integral transforms.

运用力学和电磁场的知识对厚壁圆筒结构建立平衡方程，并通过 Laplace 和 Hankel 积分变换对物理方程进行变换，得到一个可解的方程形式。

In the second parts, a method on studying stochastic transition of the Fokker-Planck equation is introduced, how to use the method of the latent root to on the Fokker-Planck equation is mainly deduced.

第二部分介绍了研究马达的随机跃迁方法-福克普朗克方程的特征根解法，着重推导了如何用特征根方法解福克普朗克方程。

We applied the Gross-Pitaevskii equation for BEC condensate in 1D optical lattice. For the character of the periodic potential from optical lattice, the Bloch function is used to expand our order parameter to get a 1D nonlinear equation of the envelop function.

我们应用Gross-Pitaevskii equation 来描述在一维光晶格中的玻色-爱因斯坦疑聚态，基於光晶格位能的周期性，我们用Bloch function 来展开秩序参数可得到封包函数的一维非线性方程式。

Orienting directed from the theory of "interbed" put forward by Leake, based on the Terzaghi\'s effective stress principle, the principle of coupling groundwater flow equation and soil deformation equation is analyzed in this paper. And the land subsidence model coupled by three dimensional groundwater flow model and one dimensional soil deformation model was built.

本文从Leake提出的含水层内的"夹层"理论出发，在Terzaghi有效应力原理的基础上，分析了地下水流方程和土体变形方程耦合的机理，建立了由三维地下水流模型和垂向一维土体变形模型耦合得到的地面沉降模型。

LBIE, based on the local boundary equation, adopts the traditional moving least squares approximation which depends on only the values of the nodes in the domain of the problem or along its boundary. The whole process of integration is carried on over a local domain or its local boundary centered at the node in question. The local boundary equation can be rewritten to represent the values of the unknown function at the point of interest, and the essential boundary conditions can be directly and easily enforced by using the Green formula and the characters of the Dirac function.

它以局部边界积分方程为基础，采用移动最小二乘近似函数，从而只需要分布在问题域内及其边界上的节点的信息值，无需划分单元；整个积分是在以节点为中心的局部域及其边界上实现，所以不需要背景积分网格；借助于格林公式及Dirac函数的性质，将局部边界积分方程转化为所考虑点的未知函数的边界积分表达式，便于直接施加本质边界条件。

In this work, the equations describing circular Gaussian beams propagating inside absorptive Keer medium have been derived from nonlinear paraxial equation. Based on the equations, an evolution equation of beam waist lias been obtained.

本文从非线性近轴波方程出发，导出了在吸收克尔介质中具有二次位相因子的圆对称高斯光束的传输方程，得到了光束束腰的演化方程。

Firstly, several kinds of schemes were proposed according to the design demand. The best scheme was chosen after analyzing and comparing the schemes. The robot's structure was designed with Pro/Engineer and AutoCAD software. Secondly, the kinematics analysis conducted, coordinate transformation matrix using D-H method was set up, and the kinematics equation direct solution and inverse solution was deduced. The manipulative interface about the kinematics equation direct solution and inverse solution was completed with VC++ and the velocity Jacobian of displacement matrix was constructed using differential transform method. In the process of the trajectory planning based on robot's kinematics analysis, I propone a method by which we can get middle nodal point with normalizing factor in order to simplify our searching for these middle nodal points. In addition, I give these middle nodal points with actual physics signification. For eliminating contradiction between real-time and accuracy, I bring forward separately limit of error and reversal interpolation method. For decreasing calculation quantity, we resort to tri-spline interpolation in the articulation space.We analyse the work range of the robot by resorting to graphic means.

首先，作者针对机器人的设计要求提出了多个方案，对其进行分析比较后，选择其中最优的方案后用Pro/Engineer和AutoCAD软件进行了机器人模型结构设计；其次，进行了运动学分析，用D-H方法建立了坐标变换矩阵，推算了运动方程的正、逆解，运用VC++制作了正、逆运动学求解的求解界面；并且用微分变换法推导了速度雅可比矩阵；在基于机器人的运动学的轨迹规划中，通过在操作空间的规划，提出了归一化因子来求解中间结点，通过它可以使求解中间结点变得更简单，并且赋予这些中间结点实际的物理含义，对于规划中精确性和实时性的矛盾，提出了以误差极限法和反向插值法来解决的方法；为了减少规划过程中计算量，在关节空间进行三次样条插值；然后借助图解法进行工作空间分析，作出了实际工作空间的轴剖图。

Chinese traditional virtue is humility and wariness,the compliment and praise to the others should be declination

中国人的传统美德是谦虚谨慎，对别人的恭维和夸奖应是推辞。如

We bought this house on the never-never.

我们以分期付款的方式买下这座房子。