晶体沉淀的沉淀条件有哪些?
参考答案:
(1)沉淀作用应在适当稀的溶液中进行;
(2)应在不断搅拌下,缓慢加入沉淀剂;
(3)沉淀作用应当在热溶液中进行;
(4)陈化。
()是投资项目评价的核心内容。
The COSPAS-SARSAT 406mhz system was adopted as an element of the GMDSS by IMO in().
A.1982
B.1980
C.1984
D.1988