在一种高分子囊材溶液中加入凝聚剂以降低囊材溶解度而凝聚成微囊的方法是
A.界面缩聚法B.辐射交联法C.喷雾干燥法D.液中干燥法E.单凝聚法
参考答案:E
Perhaps it is true that nobody in the world knows exactly how the earth __________.
A.came up
B.came out
C.came to power
D.came into being
为提高清水钻进的带沙能力,泥浆需加入()。
A.氯化钠
B.硫酸钡
C.石灰石
D.石棉粉