求翻译：由于XPS的分析深度在纳米级别，所以在进行表面元素分析时，较深处的镁元素不会被检测到，这就导致了稀土转化膜中的镁元素含量大幅下降。是什么意思？

Xps depth of analysis at the nanometer level, so during the surface elemental analysis, compared with the depths of magnesium can not be detected, which led to a substantial decline in the magnesium content in the rare earth conversion coating.

Since the depth of analysis XPS in Nm level on the surface, so the elements, a deep analysis of the magnesium element will not be detected by this has led to rare earth conversion coatings in the element content.

As a result of XPS analysis depth in nanometer rank, therefore when carries on the surface ultimate analysis, compares the deep place the magnesium element not to be able to examine, this has caused in the rare earth transformation membrane magnesium element content large drop.

Because of the depth of XPS analysis of nano-level, so at the time of surface elemental analysis, magnesium deeper will not be detected, which led to the sharp decline in rare earth conversion coatings on magnesium content in.