堆锥四分法操作,为保证缩分精密度,堆锥时,应将试样一小份、一小份地从样堆顶部撤下,使之从顶到底、从中心到外缘形成有规律的粒度分布,并至少倒堆3次()
参考答案:对
造成下列乳剂不稳定现象的原因是:絮凝().
A.Zeta电位降低
B.分散相与连续相存在密度差
C.微生物及光、热、空气等作用
D.乳化剂失去乳化作用
E.乳化剂类型改变
--- Shall we walk around the park or go for a bike ride?
--- _________. They are both good activities to me .
A.Yes, I like them very much
B.It makes no difference to me
C.That’s all right
D.I’d prefer a bike ride