查询词典 numerical system

Based on the equilibrium equation of an arch element the cubic nonlinear dynamic model with second order is established and the nonlinear differential dynamic system without constant term is obtained through a transfer process of T=U+b. Hence three fixed points and the homoclinic orbits are found. The critical condition of the chaotic vibration of the elastic arch is given by using the method of Melnikov function. The numerical results of the stationary and chaotic motion are given and discussed.

首先利用拱的单元平衡方程建立了拱的二阶三次非线性动力学模型；然后通过变换使方程转化为不含常数项的非线性微分动力系统，并由此得到无扰动系统的3个不动点与同宿轨道；再用Melnikov函数法给出了发生混沌的临界条件；最后给出了该系统出现定常运动和混沌运动的数值结果。

By using the theories and methods of impulsive,discrete and continuous dynamical system,arithmetic operators,optimiza-tion and numerical simulation,we study locally and globally asymptotieal stability of the boundary periodic solutions,and the permanence of the these systems.

以脉冲动力系统理论为基础，同时结合离散动力系统、连续动力系统、算子理论、优化理论等相关的理论和方法，在已有的研究成果的基础上，研究这些模型的边界周期解的局部和全局渐进稳定性、系统的持续生存、周期解的存在性与唯一性以及周期解的轨道稳定性等等。

The present paper proposed one kind of numerical control single-phase inversion structure, in detail elaborated the system parameter design, the rectification work basic principle of work, the contravariant basic principle and the SPWM sine pulse width modulation.

本论文提出了一种数字控制的单相逆变器结构，详细论述了系统的参数设计，整流工作的基本工作原理，逆变的基本原理及SPWM正弦脉冲宽度调制。

The presentpaper proposed one kind of numerical control single-phase inversionstructure, in detail elaborated the system parameter design, therectification work basic principle of work, the contravariant basicprinciple and the SPWM sine pulse width modulation.

本论文提出了一种数字控制的单相逆变器结构，详细论述了系统的参数设计，整流工作的基本工作原理，逆变的基本原理及SPWM正弦脉冲宽度调制。

As an important part of the open system of numerical control, the study and development of motion control board also get gradually to pay attention.

作为开放式数控系统的重要组成部分，运动控制卡的研究和开发也日渐受到重视。

This paper puts forward a united Laplacian transform which is based on the differential geometry curve coordinate system,the practical numerical experiment results show that this method has a strong edge detection ability and produces the better effect compared with old method.

该文采用基于微分几何曲线坐标系下普遍的Laplacian算子进行边缘检测，从结果可以看到处理效果明显优于普通的方法。

It is essential to design suitable coordinate system or choose suitable function family for organizing observed data,experimental results,theoretical calculation and numerical simulation.

0引言在科学研究，特别是在实验研究中，选择适当的坐标系来组织资料，或者用适当的函数来表述结果，是极其重要的一个环节。

As a result, it shows thatthe static or dynamic subsystem optimum alone is not equal to the system optimum. Three initial value problems met in the optimal design of flying vehicle are studied andconclusions are derived that: orthogonal test method can be adopted to decide the initial valueof static optimization problem, some mathematical techniques can be used to deal with thecostate variables of Maximum Principle and decide the initial value of the costate variable,the indirect method can be used to get the analytical solution under ideal case to guide thechoice of the initial control curve in the direct method. With some numerical examples oftrajectory optimization, it shows that all these methods are useful not only in accelerating theconvergence but also in converging to the global optimum.

针对飞行器优化设计中的三种初始值问题进行了研究，以远程弹道导弹弹道的工程优化为例说明，对于静态优化问题，采用正交试验法选取初始值，不仅可以大大加快收敛的速度，而且更有可能收敛到全局最优解；以气动力辅助变轨问题为例说明，用共态变量的一阶泰勒级数展开可以解决极大值原理中共态变量初值难于确定的问题；以二级弹道导弹的主动段弹道优化为例说明，利用间接法在理想情况下得到的解析解来指导直接法初始控制曲线的选择，将大大有利于提高直接法的收敛速度。

A numerical example is provided in which the characteristic of the coupling system is discussed.

通过一个算例，讨论了该耦合系统的非线性动力特性。

The curved grid is taken to constitute a generalized curvilinear system. Thus, the wave equations have to be written in curvilinear coordinates before applying the numerical scheme.

这一映射技术将直角坐标系下的曲界面变换成曲坐标系下的规则界面，在曲坐标系下用伪谱法模拟波场，最后利用插值得到实际波场的合成记录。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。