查询词典 method of difference

The principles of FEM, finite difference method , numerical mode method and integral equation method are elaborately described.

详细阐述了非均匀介质问题中常用的有限元法、有限差分法、数值模式匹配法和积分方程方法的基本原理和各自的优缺点。

In this paper, we use this numerical method and adopt operator splitting method to simulate the conduction model of action potential in two-dimensional cardiac ventricle tissue,the conduction model of the action potential in two-dimensional cardiac ventricle tissue is denoted by one reaction-diffusion equation with a series of ODE describing ionic channels of cell, at the same time,we adopt the compact alternate direct implicit difference method to simulate that model,compar-ing these value results,get some conlusions.

本文中，我们利用摄动有限差分方法和算子分裂思想去模拟二维心室肌中动作电位的传导模型，该模型由一个描述细胞离子通道的常微分方程组和一个反应扩散方程组成。

Up to now, finite difference method, finite element method and boundary element method are common numerical methods to obtain numerical solutions of parabolic partial differential equation.

目前求解抛物型偏微分方程的数值方法有有限差分法、有限元法和边界元法等。

Temperature field is obtained by Direct Finite Difference Method with parallelepiped mesh elements and the latent heat release is handled with a combination of equivalent specific heat method and temperature recovery method.

计算方法采用直交剖分的直接差分法；潜热处理采用等价比热法与温度修正法相结合的方法；在节约内存量和提高计算速度的基础上尽可能提高计算精度，并在三者之间取得合理平衡；对直交剖分带来的误差采用了热容量修正技术；针对不同铸造合金的凝固特点，对收缩缺陷判据进行了研究和扩展。

The experiment data of paramecium from Gause was used to investigate the efficiency of the method. And the twelve nonlinear real examples from "Agricultural Experimental Statistics" written by Mo Huidong were used to compare the difference between results fit by the Excel and the linear transformation method, respectively. The result showed that the Excel fitting method is not only simple and efficient for the parameter estimation but can fit various complex nonlinear equations also.

采用Gause的4组草履虫数据，研究了用Excel的"规划求解"工具进行非线性方程拟合的有效性，并以莫惠栋的《农业试验统计》一书中的12个非线性方程实例，比较了用Excel拟合与用常规线性转换方法拟合的差异，结果表明：用Excel进行非线性方程的拟合不仅简单易行、获得更优的参数估计，而且可以拟合各种复杂的非线性方程。

The classical cutting stock algorithm——column generation technology , and wrap up rectangle technology for abnormity are analyzed ; The development of AutoCAD with ObjectARX is studied and the generating method of cutting outline drawing and layout drawing were found out on the basis of analyses of the graph database structure of AutoCAD and the basic operation of it ; The process planning technology of plate material cutting orienting numerical control is studied a process planning method directly based on layout drawing is established ; The emulation technology in AutoCAD is studied and a kind of dynamic emulation method is put forward , which is realized by incrementally modifying graph entity ; The postposition of NC program of the integrated cutting system constructed on software plug-in is proposed , which can effectively solve the problem that it is difficult for a numerical control programming system to be common , which is caused by the difference of instruction format and control parameter between different type of numerical control machine .

分析了经典的矩形件优化排样算法——列生成法和针对异形件的矩形包络算法；研究了基于ObjectARX 的AutoCAD 开发技术，结合对AutoCAD 图形数据库结构及其基本操作的分析，给出了下料轮廓图和排样图的生成方法；研究了板材数控下料加工的工艺处理技术，建立了一种直接基于排样图进行的图形交互工艺规划方法；研究了在AutoCAD环境中的板材下料数控仿真技术，给出一种通过增量修改图形实体对象实现的动态仿真方法；提出以软插件技术构建集成下料系统的数控编程后置处理部分，能够有效解决因数控下料机床指令格式及控制参数不统一导致的自动编程软件系统不易实现通用性的问题。

Also the response amplitude will be changed with the initial conditions due to the nonlinear properties of the cables.Taking the bending stiffness, cable sag and cable inclination into consideration, the space vibration control of the cables using the visco-elastic dampers in cable-stayed bridges is investigated by joining the center difference method and the state space strategy. Both the maximum modal damping ration and the optimal damper size are obtained, then the practical suggestions are proposed for the design of the dampers. The space nonlinear vibration equations of the cable-damper system are derived, and anew hybrid method for solving the cable-damper system is presented by combing the Newmark method and Pseudo-force technology. According to the known properties of the cable-damper system, the nonlinear transient responses are analyzed under all kinds of excitations. Based on the transient response, the control effectiveness of the visco-elastic dampers is further demonstrated.

综合考虑了拉索抗弯刚度、垂度的影响，研究了粘弹性阻尼器对斜拉桥拉索的空间振动控制，联合中心差分方法及状态空间法，得出了拉索面内、外振动各阶模态可能达到的最大阻尼比及相应的最优阻尼器系数，并对斜拉桥拉索的阻尼器设计提出了参考建议：考虑拉索抗弯刚度、垂度及几何非线性，导出了索-阻尼器系统的空间振动非线性方程组，结合Newmark方法及伪力(Pseudo-Force)方法，创新地提出了求解非线性方程组的杂交方法，根据拉索-阻尼器系统的阻尼特性，在各种荷载作用下，对索-阻尼器系统的非线性瞬态振动响应进行了研究，从系统响应的角度更加直接地验证了阻尼器的控制效果。

Gabor-ring is often used in texture feature extraction, but it is based on the assumption that texture is narrowband signal and can not applied to most actual textured images that have more than one center frequency in power spectrum. To overcome the limitation of existing method, an improved method is proposed. According to this method, Gabor filters are constructed in accordance with the spectrum feature vector of texture, and a relaxation parameter is used to determine the effect of difference filters so as to integrate the frequencies and phases into the process of extraction.

Gabor环（即在频率域成环形分布的Gabor滤波器组）常被用于提取图像纹理特征，但它是以"纹理是窄带信号"为基础的，实际的纹理图像并不能很好地满足"窄带信号"的假设，用一个中心频率来描述一种纹理对能量集中在多个频率点的纹理图像往往不能取得理想的效果，而根据频谱特征值向量构造Gabor环的改进方法，通过松弛因子的加入改变不同滤波器的作用强度，综合考虑了多频率多相位对纹理特征提取的影响。

Aiming at these problems, we have designed the processing workflow to effectively suppress the surface Wave interference, regular interference, high energy interference, and other random noise interference. The treatment clue was from thick to thin. Firstly, the spectral analysis method was used to establish macroscopic velocity field. Then, the ray tomography method was used to enhance the accuracy of velocity analysis and to establish a more accurate velocity model. Finally, the finite difference pre-stack depth migration on method in -k domain was adopted to solve the imaging problem of subsalt and salt dome flank.

通过合理组织处理流程，有效压制了面波干扰、规则于扰、强能量干扰和随机噪声干扰；采用由粗到细的思路，先利用谱分析方法建立宏现速度场，再利用射线层析成像方法提高速度分析精度，建立了较为准确的速度模型；利用频率－空间域有限差分叠前深度偏移解决了盐下及盐丘侧翼的成像问题。

In this dissertation, the numerical method solving the model equation influid motion in some sense has solved some tough problems which traditionalmethods cannot, as in the case of capturing shockwave, enhancing resolution, andspeeding computation. In terms of capturing shockwave and enhancing resolution,this method has proved to be superior to difference method; in terms of speedingcomputation, superior to TVD scheme. Particularly, it is highly effective to solveodd singular solution problems.

本文研究的求解描述流体运动的若干模型方程的数值方法，在一定程度上解决了传统方法在某些方面的难点问题，如在捕捉激波、提高分辨率方面优于差分法，在计算速度方面优于TVD格式，特别是对处理有奇异解的问题很有效。

Pachomius manual labour was organized as an essential part of the monastic life; and since it is a principle of the monks as distinguished from the mendicants, that the body shall be self-supporting, external work of one sort or another has been an inevitable part of the life ever since.

根据圣pachomius体力劳动组织作为一个重要组成部分寺院生活；以来，这是一个原则的和尚，作为有别于乞丐，该机构应自支撑，对外工作的这种或那种已一个必然的一部分，生活至今。

In order to study the effects of parametrical rolling on the ship movement and tilts, in allusion to ship's navigating in regular following waves, the equation of ship rolling motion is transformed into normal Mathieu equation by proper variable replacement when strong parametrical excitation in restoring moment varied according to sine or cosine wave.

为研究参数横摇对船舶运动和倾覆的影响，通过对船在规则波上随浪航行时，恢复力矩中出现的1个以正余弦规律变化的强参数激励项进行适当的变量置换，将船舶的横摇运动方程转换成标准形式的Mathieu方程。