它們各道出一定的分層道理，但又都不完善，只可根據(jù)實(shí)際情況適當(dāng)引用（參閱重選基本原理）。
從動(dòng)力學(xué)角度看，床層中顆粒大致有三種運(yùn)動(dòng)形式：（1）加速度運(yùn)動(dòng)；（2）干涉沉降運(yùn)動(dòng)；（3）細(xì)顆粒透過床層間隙的鉆隙運(yùn)動(dòng)。這些運(yùn)動(dòng)在周期的不同階段各有不同的發(fā)展。

They each certain hierarchical sense, but are not perfect, only according to the actual situation of the appropriate reference (see gravity basic principle).

從動(dòng)力學(xué)角度看，床層中顆粒大致有三種運(yùn)動(dòng)形式：（1）加速度運(yùn)動(dòng)；（2）干涉沉降運(yùn)動(dòng)；（3）細(xì)顆粒透過床層間隙的鉆隙運(yùn)動(dòng)。這些運(yùn)動(dòng)在周期的不同階段各有不同的發(fā)展。

From the dynamic point of view, there are three kinds of particles in the bed layer: (1) the acceleration motion; (2) the movement of the interference (3). These movements have different development in different stages of the cycle.