无周期运动

Through an infinitesimal contact transformation, the system was deduced to a torque-free rigid body with moments of inertia varying periodically with time. It can be taken as a Euler-Poinsot motion perturbated by small periodic excitation.

通过无限小接触变换，将系统等价为无力矩作用下自由刚体运动，但其转动惯量仍随时间周期地变化，从而化作周期摄动的Euler-Poinsot运动。

Bloodless and many footed animals, whether furnished with wings or feet, move with more than four points of motion; as, for instance, the dayfly moves with four feet and four wings: and, I may observe in passing, this creature is exceptional not only in regard to the duration of its existence, whence it receives its name, but also because though a quadruped it has wings also.

无血多足动物，不管装备翅膀还是足，移动依靠多于四个的运动点：像是，例如，蜉蝣依靠四足和四翅膀活动：并且，我可以顺便说一下，这种生物的特别不仅与它的生存周期、名称的由来有关，也因为它尽管是四足动物，但是也有翅膀。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。