不稳定状态

Based on varying process of generator terminal parameters after excitation fault, shortages of excitation protective principle of static stability boundary and asynchronous impedance boundary are analyzed. It proposed that excitation fault research relates to large-disturbance stability. Because dynamic power-angle character of generator after excitation fault is non-sinusoidal, there are differences between dynamic power-angle character and static state power-angle character. So it isn't ideal to protective operation result based on small-disturbance stability and static stability boundary criterion. At the same time, it proposed that asynchronous boundary impedance criterion is a constant reactive power circle moving adown j Xd′. It can ensure complete loss-of-excitation generator measuring impedance enter into the circle, but can't ensure the other condition measuring impedance including impossible losing synchronism enter. So loss-of-excitation protection would be maloperation when system voltage drops short and recovers or generator rejects load.③Based on stability principle, it puts forward setting conditions and calculation method of generator loss-of-excitation protection by direct measuring power-angle.

以励磁故障后发电机端的相关参数的变化为基础，通过对以静稳定边界和异步阻抗边界作判据的两类三种现行励磁保护在原理上存在的缺陷分析，发现：励磁故障是一个大干扰稳定性问题，励磁故障后的发电机的动态功角特性与静态功角特性有很大的差异，已远非正弦曲线，因此基于小干扰稳定性原理、以静稳定边界作判据的保护必然动作不理想；异步边界阻抗判据是一个下移j Xd′的等无功阻抗圆，它可以保证完全失磁后的发电机测量阻抗能进入该阻抗圆，但不能保证完全失磁之外的其它状态不会进入该阻抗圆，因此在系统电压短时下降或发电机突然甩负荷等情况下可能启动该保护使之误动。

Based on this notion and the invariance principle, a condition is proposed and proved, under which an invariant set of states of a switched system with Lyapunov stable subsystems can be stabilized by state feedback.

基于这个不变性原理以及输入对系统能量函数稳定的概念，利用多Lyapunov函数方法提出并证明了一类具有Lyapunov稳定子系统的切换系统的不变集可状态反馈镇定的条件。

The sufficient conditions to guarantee robust exponential stability for the closed-loop systems are obtained based on Linear Matrix Inequality, moreover, the approach of design of robust H# output feedback controller is introduced.3 The problem of reliable H# control for a class of Lur"e systems with polytopic uncertainties is studied when all control components are operational as well as when some control components experience failures, the design approach of reliable H# controller is also obtained.4 Considering a class of uncertain Lur"e singular system with time-delays, the problem of robust stability is investigated based on Barbalats Lemma and nonsingular linear transformation of model reduction.

针对一类不确定Lur'e奇异时滞系统，基于Barbalat引理以及非奇异降阶变换，讨论了Lur'e奇异时滞系统的鲁棒稳定问题，提出了鲁棒H_∞状态浙江大学博士学位论文反馈控制器的设计方法。5、针对一类具有饱和执行器的不确定Lur'e奇异系统，提出了时滞依赖的鲁棒稳定与鲁棒二次镇定的充分条件，所的结果不需要参数的整定。6、针对任意协方差有界的有色噪声，讨论了一类不确定Lur'e奇异系统的鲁棒凡滤波问题，得出了鲁棒几滤波器设计的充分条件。7、针对一类不确定Lur'e时滞系统，通过线性变换，把它转换成奇异系统，根据奇异系统鲁棒控制理论所得出的鲁棒稳定与鲁棒镇定控制器设计的充分条件具有很小的保守性。

In this chapter, three kinds of target recognition methods are performed, which are:①Target recognition method based on the description of polarization parameter plane. The echo polarization states of target are projected onto the polarization state plane described by the ellipticity ε and the tilt angle τ of the polarization ellipse, the change of parameter following ferquency becomes the chart. According to the changing trait of the chart, the multidimensional polarization feature space of target has been contructed. Furthermore, a series of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.②Target recognition method based on the description of Poincare polarization sphere. The echo polarization states of target expressed by Stokes vector are projected onto the Poincare polarization sphere. The conception of polarization ferquency stability, which is used in describing the dynamic distribution characteristics of the target echo polarization states on Poincare polarization sphere, has been defined. A group of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.③Target recognition method based on the description of frequency sensitivity. In accordance with the conception of the polarization state distance defined on Poincare polarization sphere, the frequency sensibility of the physical structure property of target has been investigated, the frequency distribution feature curves in PSD domain are obtained, and targets'features are extracted by means of the curve-fitting method with Least Square Criterion.

这章具体研究了基于三种极化散射特性描述的相应的目标识别方法：①基于极化参数平面描述的目标识别方法，将目标回波极化状态投影到以极化椭圆参数，即椭圆率角ε和倾角τ表征的极化状态平面上，参数随观测频率的变化就形成了图，根据图的变化特点构造了目标的多维极化特征空间，并提取了不敏感目标姿态变化的极化特征参数组来设计目标的识别器结构；②基于Poincare极化球面描述的目标识别方法，采用Stokes矢量表征目标回波的极化状态，并将其投影到描述极化状态的Poincare极化球面上，定义了极化频率稳定度的概念用以刻画目标回波极化状态在Poincare极化球面上的动态分布信息，提取了准方位不变性的目标极化特征，最后设计了目标的识别器结构；③基于频率敏感性描述的目标识别方法，通过在Poincare极化球面上所定义的极化状态距离的概念，研究的是复杂目标物理结构特性对探测信号频率的敏感程度问题，获得了在极化状态距离下的频率分布特性曲线，采用最小二乘估计曲线拟合方法，它既用于极化特征的降维，同时又直接将拟合参数作为目标的分类特征。

The basic study content of this essay is follow as:1.To calculate the stable factor k_i~0 of individual slices according to self-forced condition of slices,under the condition of without inter-slices force.2.To calculate transferal force R_i, stabile factor K_i of individual slices and stabile factor K of the stable slope, under the condition of there is a level transferal force between slices and the slope is stable. If the slope is not stable, to calculate the transferal force R_i between individual slices, the stabile factor K_i of individual slices and the stable factor K of the unstable slope in term of concordant conditions of acceleration.

本文研究的基本内容包括： 1、研究土条条间不传递力情况下，由土条自受力状态计算各土条的稳定系数K_i，并由K_i计算稳定土坡的稳定系数K； 2、研究条间传递水平力情况下，若土坡稳定，由土条预平衡状态、传力顺序和传力边界条件，推导各土条间的水平传力R_i的理论公式和各土条的稳定系数K_i，并由K_i计算稳定土坡的稳定系数K；若土坡失稳，由加速度和谐条件计算各土条间的水平传力R_i和各土条的稳定系数K_i，并由K_i计算失稳土坡的稳定系数K

In China the spinners and weavers have suffered greatly under this foreign competition, and the community has become unsettled in proportion.

在这样的国外竞争之下，中国的纺织工们遭受了巨大的打击，整个行业也在协调上出现了不稳定的状态。

When the two grid-electrodes are "floating", the unstability of plate electrode current is measured to indicate the random diffusion of electrons and ions and the existence of voltage noise.

观测了两栅极之间处于&悬浮&状态时板极电流的不稳定，反映了电子和离子扩散的随机性与噪声电压的影响。

One of these remains politico-military, the other three are in new and from a security perspective unfamiliar dimensions, but no less dangerous for that. They include global hierarchical tensions, ecological degradation and domestic social instability.

它们中的一个来源于政治军事，另外三个是新生的并且来自于一个奇特的安全观察尺度，但并不为此减少危险，它们包括全球分等级紧张状态、生态的退化和家庭社会的不稳定。

In the state of vacuum,the boilling point of raw material will be dr-opped.therefore it is suitable for drying raw materials that are unstable or thermalsensitive.the vacuum drier also has good airtighenss.so it is also for drying raw materials that contain strong irriative and toxic gases and toxicgases and the solvent needs to recover.

真空状态下物料溶剂的沸点降低，所以适用于干燥不稳定或热敏性物料；真空干燥机有良好的密封性，所以又适用干干燥需回收溶剂和含强烈刺激，有毒气体的物料。

In addition, the above from your computer that started the voice of a great situation, may be the voice of the hard disk, then it may be hard work has been instability in the state, please note that check.

另外，从您上面说的计算机启动后声音很大的情况来看，可能是硬盘发出的声音，那么也可能是硬盘工作状态已经不稳定了，请注意检查。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。