矩问题

This technique is used for the axisymmetric magneticstatic problems and the result is good. In the second example of the forth chapter, the error of the third–order Asymptotic Boundary Condition is lower than that of the second-order Asympototic Boundary Condition.

第五章针对这一问题，进一步对渐近边界条件进行了推导，分析了一些特殊电荷和电流分布情况下，电位、标量磁位和矢量磁位的多极矩展开式中各极矩项的性质。

A method of moment features testing components' states is put forward to solve this problem.First the components' barycentric coordinates and second-order centered moments are calculated.Then the inclined angles are obtained,on the basis of which the inclined components can be rectified.

针对这一问题，提出了一种矩特征检测构件状态的方法，该方法首先计算出图像中构件的质心坐标和二阶中心矩，然后求出构件的倾斜角度，根据倾斜角对处于倾斜状态的构件进行校正。

Via the stochastic averaging method, the four-dimensional system is reduced to a two-dimensional one. Through the logarithmic polar transformation , and then Girsanov theorem and Feynmann-Kac formula, the backword differential operator is then obtained. By expanding the eigenfunctions as a Fourier cosine series, the approximate analytic expansion of the moment Lyapunov exponent is then obtained.

首先在经典二元机翼颤振方程加入随机激励，通过随机平均法，Girsanov定理和Feynmann-Kac公式得到关于矩Lyapunov指数的特征值问题，其次采用Fourier余弦级数对特征函数进行正交展开得到系统矩Lyapunov指数的近似解析式。

In the aspect of multivariate modeling, three forms of multivariate GARCHSK model includes vector form, diagonal form and simplify form, are put forward and compared. The famous dimension disaster exists in multivariate GARCHSK model also. Based on Independent Component Analysis, multivariate volatilities of conditional higher moments are estimated through IC-GARCHSK model, which make dynamic relation of higher moment risk between multi-assets to be possible.

鉴于多元 GARCHSK 模型存在严重的"维数灾难"问题，基于独立成分分解技术提出 IC-GARCHSK 模型，给出多元条件高阶矩波动率的估计方法，使得同时度量多个资产高阶矩风险之间动态关系成为可能，为利用组合投资方式分散高阶矩风险的影响奠定了方法论基础。

This paper considers the moment problem for modules over principal ideal domain containing existence and uniqueness of solution.

研究主理想环上模的矩量问题，包括矩量问题的存在性和唯一性。

Due to the large torque ripple of direct torque control in low speed range,a torque angle adjustor based on fuzzy neural network and PI control was adopted to improve the control effect.

针对直接转矩控制低速时转矩脉动大的问题，采用基于模糊网络与PI控制结合的转矩角调节器来改进控制效果。

This dissertation systematically surveys the development history of stator direct self control of the induction motors. Some main problems in the DSC method are pointed out and a new kind of intelligent DSC method is put forward.

本文系统地综述了直接转矩控制的产生与发展，指出了直接转矩控制方法中存在的主要问题，提出了一种新的智能直接转矩控制方法。

Direct Torque Control is a novel torque controlling technique which was proposed in 1980's. Although this technique has received a successful application in high-power ac drives recently, there are also a great deal of problems in the theories and practics which deserve to research. Centring around how to find and solve these prombles, theorical analyses, computer simulation and experimental studies are carried out in this dessertation.

直接转矩控制是八十年代提出的一种新型感应电机转矩控制技术，目前该项技术在国外电力牵引中的大功率交流传动上已获得成功的应用，然而作为一项新技术，它在理论上和实践中仍存在许多值得研究和探讨的问题，本文的研究正是围绕着这些现存问题而展开的。

The first control strategy has the disadvantages such as a large amount of computations, inherent pull-out torque, difficulties in realizing the adaptive control and so forth. For the rotor flux-oriented control, changing of load or the rotor speed will result in increased or decreased torque winding currents, which will change the magnetic field distribution in the air gap. Assumption that magnetic field is approximately equal to that generated by torque windings will affect the levitation performances.

分析表明：气隙磁场定向控制中存在最大转矩限制、非线性机械特性，难以实现自适应控制等问题；对转子磁场定向控制而言，当负载或转速变化时，由于转矩控制绕组转矩电流变化将导致气隙磁场发生改变，如果仍以转子磁场近似替代气隙磁场作为悬浮依据，必然影响到悬浮控制性能。

This paper introduces the control principle of the direct torque control system of an asynchronous motor,and proposes a new strategy to solve the problem of the large torque ripple and current ripple.

本文介绍了直接转矩控制系统的控制原理，并针对基于直接转矩控制的异步电动机运行时存在较大的电流及转矩脉动问题，提出一种新的控制方案，并基于Matlab 6。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷