n.分别，分馏法
These early observations have been supplemented with results from chemical fractionation.
这些早期的观察曾为化学馏分的结果所增补.
The second general problem of cell fractionation is the contamination of each fraction by others.
细胞组分分离的第二个普遍问题是各组分的相互掺杂.
The effects of fractionation are dependent on total doses and on fractionation procedures.
分次照射的效应取决于总计量和分次方法.