不变的

The results are applied to absolute stability problems, and the time-varying circle criterion is given.

这样就弥补了以往的结果只能处理时不变问题而难以处理时变问题的不足。

Because contravariant redefinition of method is not consistent with traditional programming style, covariant redefinition of method is preferred to as the mechanism to support specialization.

反变的方法重定义不符合思维习惯，一般采用协变精化的设计方法。

Necessary and sufficient conditions of the robust positively invariant sets are established for the linear discrete-time system family specified by matrix convex polyhedron and additive interval disturbances.

对由矩阵凸多面体和加性区间扰动描述的线性时变离散系统族，得到了鲁棒正不变集的充分必要条件；对非线性系统族则得到有关充分条件。

Libermann.The early researcheson this kind of manifolds were closely related to Physics and Mechanics.But since1991,S.Kaneyuki published his result on the algebraic condition for the existence ofinvariant〓structures on a coset space,Lie theory has played the most impor-tant role in the study of this kind of manifolds.In particular,dipolarizations in a Liealgebra are closely related to the homogeneous〓manifolds.Dipolarizationsin semisimple Lie algebras and the homogeneous〓manifolds associated withthese dipolarizations have been studied by S.Kaneyuki,Z.X.Hou and S.Q.Deng.Inthe partⅡ of this thesis we study the dipolarizations in some quadratic Lie algebrasand the homogeneous parakahler manifolds associated with these dipolarizations.

Libermann给出的，早期的有关类流形的研究与物理和力学密切相关，自从1991年金行壮二发表了陪集空间上存在不变仿凯勒结构的代数化结果后，李群及李代数理论在这类流形的研究中起着主要作用，特别地，李代数的双极化与这类流形密切相关，半单李代数的双极化的相关几何，金行壮二，候自新和邓少强等人已作了研究，二次李代数是比半单李代数更广且带有非退化不变双线性型的李代数，本文主要研究了二次代数的双极化及相关几何。

XRD indicated that the replacement of the terephthalate anion by the polytungstate anion had little effect on the structure.

结果表明，经过同多钨酸根阴离子的交换以后，垂直于水滑石层板方向的平行层板方向的晶格参数值变小，平行层板方向的晶格参数值不变，(003)、(006)、(009)衍射峰处的层间距值比为3：2：1；交换过程没有改变水滑石的结构，水滑石原位生长在γ-Al2O3表面及内孔，比表面积由γ-Al2O3载体的219平方公尺/g增加到247平方公尺/g，孔径分布则由原来的2~11nm变化为3~4nm。

After converting input color images from RGB to YIQ color space and obtaining I component images, the system scales and scans the whole images and thresholds them to extract skinlike regions that may contain human faces.

首先把输入的彩色图像从 RGB转换到 YIQ颜色空间，提取与人的肤色相关的 I分量图像，通过对整幅 I分量图像进行尺度变化和窗口扫描，解决待测人脸的位置、大小不同问题，实现平移不变和尺度不变。然后对 I分量图像进行门限化处理，提取 I分量图像中可能包含人脸的接近人的肤色的区域。

Based on that, two particular indentities of unitarily invariant metrics are obtained.3 Perturbation analysis of the canonical subspaces: This paper gives the least perturbation bound of the unitary factor on the unitary decomposition.

并利用C-S分解，给出了这类新的酉不变度量的上下界。由此，得到两个特殊的酉不变度量的恒等表达式。3 标准子空间的扰动分析：本文给出了矩阵的酉分解中酉因子的最小扰动界。

This paper then compares three kinds of power conversion circuit applied in it and advances a main circuit which is based on IGBT's power grade nowadays and is applied in high power direct-driven grid-connected wind turbine. It is made up of a six-phase rectifier, two paralleled BOOST chopper circuits and two paralleled SPWM inverters.

文章在比较此种风力发电机的三种类型变流电路拓扑结构的基础上，提出了一种在考虑现有开关器件功率水平的情况下符合大功率直驱并网型风力发电机要求的变流电路拓扑结构，即采用&六相不控整流+两个并联的升压斩波+两个并联的三相SPWM逆变&的电路结构，并对其各部分电路的工作原理进行了分析。

Comparing comprehensive ly the present various current converting circuits, it is proposed an design structure of direct-driven wind power generation current converting systems in megawatt level.

摘 要：在综合比较当前适合直驱型风力发电机组的各种变流电路的基础上[1~ 2]，提出了一种兆瓦级直驱型风力发电变流系统的设计结构，即采用不控整流+升压斩波+SPWM逆变的变流器将电机发出的电能转换为可接入电网的恒频恒压的交流电。

The latter is called complementary distribution; they are two allophones of the same phoneme. They only occur in different environments.

互补分布是指音位变体之间的关系，同一个音位的不同变体在语音组合中永远不会出现在相同的位置上，它们没有区别意义的作用，如 top 中的送气的和 stop 中不送气的。

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。