Results of elec-tron probe analysis for the stria region show that increase of Nb~(5+) concentration in thestria region and deficient in Mg~(2+) in the boundary layer are the main causes for the for-mation of the growth striae.

• 对条纹区的电子探针分析表明:Nb~(5+)浓度在条纹区的剧增和Mg~(2+)浓度在边界层的贫化是形成生长条纹的主要原因。