在前后

As a coelostat, MA tracks the motion of celestial objects observed at their meridian passages.

MA作为定天跟踪天体的运动，望天体中天前后进观测。

The extract of Sophora japonica L. was processed by inorganic ceramic membrane, and the whole solid, effective ingredinent and flux of mebrane were examined.

用孔径为0.2μm的无机陶瓷膜槐米提取液进微,提取液微前后总固体、性状、指标性成分、膜通量等方面的变化进分析。