powdery substance是什么意思

用法例句

The characteristics and molding process parameters of PS powder was introduced.

指出对PS粉末烧结成型件进行不同的后处理,可将其作为原型件、功能件或精铸模具使用。

A new definition of PS-compactness and PS-Lindelf property is presented in L-topological spaces by means of pre-semiopen L-sets and their inequality,where L is a complete DeMorgan algebra.

在L-拓扑空间中借助于准半开L-集及其不等式给出了可数PS-紧性和PS-Lindelf性质的新定义,这里L是完备的DeMorgan代数。