不变

Since the eigenvalues of JM may be real, or pure imaginary, or some are real and others are imaginary, the presived tori may be hyperbol

我们考虑如下的依赖于参数的Hamilton系统：在以上假设下，我们证明了系统(3)的双曲不变环面大多数在摄动之下可以保持下来，并且频率可以是预先给定且可以保持不变的。

In chapter 3,we dig out two families of invariant quartic curves of a quadratic system.

第五章讨论向量场具有对称中心的二次系统，利用系统的不变双曲线及不变四次曲线，我们确定了一个对应极限环（1.1）分布的二维参数区域，其边界的构成为如下几种常见的极限环分枝：霍夫分析，庞加莱分枝，同宿分枝和异宿分枝。

At last , some investgation is made to change about elementary constant of the universe in today ,which demonstrates that elementary constant of the universe in today would change at a ratio of 2.3387723548904887*1050 per year which means that elementary constant of the universe in today would remain as an constant unchanged within one million years if its accuracy fix on the 4th digit after radix point of 7.7577806787995708*1060 As a reminder , both elementary constant of the unvierse elementary constant of the unvierse in today have nothing to do with the cosmic constant introduced by Mr.

基本宇宙常数是一个变化的物理常数，其数值变化的速率为：2.3387723548904887*1050 ，与今天基本宇宙常数7.7577806787995708*1060 相比较，如果在保持今天宇宙常数的数量级不变的情况下将精确度选定在小数点后第4位，那么今天基本宇宙常数将在100万年之内保持不变。

By using integral periodogram to estimate the spectral functions of a stationary time series, the invariance principle for the error process has been demonstrated either for Gaussian or non-Gaussian series.

用积分周期图估计平稳时间序列的谱函数，不论是高斯序列还是非高斯序列，其误差过程的不变原理都已被证明￣（［1］，［3］），许重光￣［5］采用自迥归谱估计的积分估计谱函数也证明了误差过程的不变原理成立。

This paper attempts to find a lower-order state space symmetric model whose model reduction cost differs from the optimal model reduction cost by a prescribed precision.

该文试图寻找一个低阶隐定连续线对称性时不变系统，其与给定的高阶隐定连续线对称性时不变系统的L2 -范数误差可与最优误差值充分接近。

This paper deals with the problem of finding a lower-order linear continuous time-invariant stable state space symmetric system to approximate a given higher-order linear continuous time-invariant stable state space symmetric system so that the L_2 norm of the model mismatch is minimized.

研究用一个低价隐定连续线对称性时不变系统去近似一个高阶隐定连续线对称性时不变系统以使它们之间的L2 -范数误差最小化。

And local coordinate representations of left invariant symplectic structure and symplectic left invariant vector field on the Symplectic-Lie group are given.

还给出了辛李群上左不变辛结构和辛左不变向量场的局部坐标表示。

Nevertheless, Talmudic study has remained entirely unchanged in a very important respect, and will remain unchanged as long as people engage in it.

尽管如此，塔木德研究仍然完全不变的一个非常重要的方面，将保持不变，只要人们从事它。

Again,he stands there quietly,saying nothing.that's around 5.40am AD 451,in Catalaunian Plain,time freezes at that moment.the sun and the fading moon and stars which has been unchaged for millions and millions of years and will still be unchanged for millions and millions of years and the softened eye lights of hundreds of thousands of brave Roman soldiers are the testimony forever.long time's silence,and general puts on his visor at last and again mounts his horse,he makes a gesture to order his troops to make a circuit,King Theodoric catches up with him,all those soldiers follow closely behind them

那是公元四百五十一年七月二十五日清晨五十四十分左右，时间仿佛在那一刻凝固，那亿万年不变的太阳和那亿万年不变星光以及几十万的罗马战士突然柔和下来的目光是永恒的见证。

Equivalence of invariant mean and topological invariant mean is showed by two methods.

用两种方法证明左不变平均和拓扑左不变的等价性。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。