查询词典 perturbation function

Firstly, This paper processes geometry filtration based on character of orbit's apogee and perigee after orbit model is analyzed and based. Secondly Space Debris is separated into two kinds, coplanar and not coplanar according as location interrelation of target and debris. In Dynamic filtration's processing, considering prediction time limit and orbit perturbation, secular effects which have increaser effect is considered so that some need catching danger time point is appeased, some law about time when target and debris pass intersectant line each other is inferred, when debris and object are in different plane and some similar law also is inferred otherwise. The time list is arithmetical progression. These laws can improve calculation efficiency remarkably; Lastly orbit predict is a course approaching least distance. Danger time point in the last step become beginning time point from which debris and object's position and velocity are calculated by SXP4 Model which is an analytic model.By result, determine that relative movement trend is closer or apart, farther calculate the interval apart from time when predictive least relative distance occurs. Least relative distance and time when least distance occurs is calculated finally. It is a fast approach course adopting varied interval.

本文在分析、建立轨道摄动计算模型的基础上，首先采用基于轨道远、近地点特征对大量编目在册的空间碎片进行初步几何静态筛选，然后根据碎片与目标轨道面的相对位置特点把碎片分为异面与准共面两种情况以进行动态筛选，在筛选过程中考虑到预报时限长度和轨道摄动影响，引入了轨道摄动中具有积累效应的长期项以满足危险时间点的捕捉要求，利用了长期项摄动变化线性的特点导出了碎片与目标异面情况下各自过交线的时间序列成准等差数列的规律性和准共面情况下类似的规律性，从而显著地提高了前期轨道筛选的计算效率；最后对剩余危险碎片和目标飞行器利用SXP4轨道预报模型在前期轨道筛选的基础上以各个危险探测时间点为预报的时间起点，并根据预报计算结果，分析目标和碎片在该时间点的运动趋势是相互远离还是相互接近，推出预计最小相对距离发生时刻相对此刻的时间长度，得到其随时间变化的局部最小相对距离以及危险距离发生的时刻和相对速度，这是一个采用变时间步长、快速逼近最小相对距离的过程。

In order to reduce the influence caused by the controller parameter variations and the plant parameter perturbation, and assurance the tracking performance and the restraint disturbance performance, the improved robust two degree-of-freedom control structure and the linear matrix inequation design method are adopted to design the robust two DOF controller of the servo system in this thesis.

为了降低控制器参数及被控对象参数摄动对系统性能造成的影响，同时，保证系统的跟踪性能和抗扰性能不变。

Design method of the electromechanical actuator controller based on the robust mixed H2/H* control theory is studied, taking advantage of the priority of the linear matrix inequation in solving the problems of the multiobject control, the robust mixed H2/H* control problem of the electromechanical actuator under the condition of parameter perturbation and external disturbance can be transformed to the solving of the linear matrix inequation.

研究了基于鲁棒H_2／H_∞混合控制理论的电动舵机的控制器设计方法，利用线性矩阵不等式在多目标综合控制问题求解方面的优势，将存在参数摄动及外部扰动时的电动舵机的鲁棒H_2／H_∞混合控制问题转化为线性矩阵不等式问西北工业大学博士学位论文题并进行求解。

This dissertation studies perturbation bounds of infinite dimensional operatorsand operator equations.We obtained the following main results.

本文讨论了Hilbert空间和Banach空间上线形有界算子和算子方程的扰动理论，得到了一系列结果。

The algorithms of estimation of infinitesimal perturbation analysis for AFJQNS with infinite queueing spaces are given.

4对具有无限缓冲容量的一般AFJQNS系统，给出了无穷小摄动分析估计的算法，并采用样本路径凸分析方法，证明了此估计具有强一致性。

In this paper, we study the initial value problem of Duffing equation in the difference form with multiple-scale method, which is one of the perturbation method.

本文以摄动法中的多重尺度法为基础，讨论差分形式的Duffing方程的初值问题。

Singular perturbation of three-point boundary value problem for third order nonlinear equation is studied by using of Volterra type integral operator and differential inequality techniques.

讨论了三阶非线性微分方程三点边值问题的奇摄动。

According to the electric field integral equation of the surface, the recursive solution for the induced current on the slight rough surface is derived using the perturbation expansion of the surface, and the method for computing the interaction field is given.

根据粗糙表面电流积分方程并利用表面微扰展开，得到了微粗糙面表面极化电流的迭代解，给出了耦合电场的计算方法。

Phonon spectrum throughout the Brillouin zone and the interatomic force constants are obtained using the density-functional perturbation theory by the linear response method.

在密度泛函微扰理论的框架下采用线性响应的方法得到了整个声子谱，并分析了原子间力常数。

The exchange energy for the electron transfer process at large internuclear distance may be calculated using either perturbation or variational method.

中文摘要与电子传递相关的远程交换能可用微扰法或变分法计算。

Now he worked in ajoint venture.

现在他在一家合资企业工作。

More troops in Afghanistan won't change any of the foregoing.

更多的在阿富汗的军队也不会改变之前的状况。