Through set sequence is resolved into finite mutually disjunct subsets, the new method to solve the limit superior and limit inferior of set sequence is give.

通过将集列分成有限个互不相交的子集列，给出了求集列的上限集和下限集的新方法。

The practicable inferior limit of analysis is 0.001%, when ICP-AES with the system is used for analysing trace soluble aluminum in silicon steel.

采用该系统的ICP - AES摄谱法、分析硅钢中微量可溶铝，实际达到的分析下限为0.001%。