descension

1.And the application of the velocity of uniform descension in determinationof particle size and distribution is discussed.

分析了沉降终速在测定颗粒粒径大小及其粒度分布中的应用；

2."My means of ascsion and descension consist only in dilating or compressing the gas inclosed in the balloon."

“我降的方法，是里的和收缩。