查询词典 perturbation method

However, the solutions of the Cauchy problem of the nonlinear hyperbolic system generally develop singularities in finite time even if the initial data are small and smooth.For this reason, solutions must be found in the space of discontinuous functions. Therefore, one can not directly use the classical analytic techniques that predominate in the theory of partial differential equations of other types. Instead, we construct approximate solutions via the singular perturbation methods. By using the compactness of the approximate solutions, we can obtain the existence of the solutions of original system.

然而一般而言，即使是在初值很小且光滑的情况下，非线性双曲型守恒律的Cauchy问题的解在有限时间内也会出现奇异性，为此，我们必须在不连续函数空间中寻找上述问题的解，因此对这类问题的研究，我们也不可能直接利用在其它类型的偏微分方程中占主导地位的解析方法来解决问题，而是通过奇异扰动法构造近似解，由近似解的紧性得到原问题解的存在性。

Research suggests that the primary hypothalamic perturbation in the HPA axis in depression might consist of increased numbers of CRF-containing neurons and CRF mRNA in the paraventricular nucleus, which leads to hypersecretion of hypothalamic CRF.

一些研究提示，抑郁症患者HPA轴中下丘脑的原发性功能紊乱包括室旁核中CRF神经元和CRF mRNA数量的增加，这将导致下丘脑CRF的过度分泌。

A kind of one parameter planar singular perturbation equation is studied by the qualitative theory of ordinary differential equations, asymptotic analysis methods, implicit function theorem and fixed point methods.

本文应用微分方程定性理论、渐进分析方法、隐函数定理以及不动点理论的方法研究一类单参数二维奇异摄动系统。

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。

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。

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。

In their studies, several important results have been obtained, using interval analysis and matrix perturbation techniques.

但他们的结果是以下述假设为基础的：ΔK和Δf在方程KU=f中是预先设定的；ΔK和ΔM在方程KU=λM中也是预先设定的。

For the integrable Hamilton systems, the Invariant tori can be continuation in a certain range if the perturbation of the coupled systems is small enough.

对可积分的Hamilton系统，加上足够小的扰动，系统的不变环面所代表的规则运动在一定范围内都是可延拓的。

In this paper, we focuse on the perturbation properties of W-weighted Drazin inverse, which is the weighted form of Drazin inverse.

本文主要讨论了 Drazin 逆的加权形式——加 W 权的 Drazin 逆的扰动性质。

You'll be in trouble it you don't watch out .

如果你不注意，你会有麻烦的。

Shaped like a biconvex lens.Of, relating to, or having the form of a hyperbola.

双曲线的属于双曲线的，与之有关的，或有双曲线形状的