Key points are not available for this paper at this time.
The heterogenous structure of nanostructured materials distinguishes them from materials such as glasses which have a homogeneously disordered microstructure. In the figure, the atoms marked in black are in the center of the grains, the white one forming the surface of the individual grains, this structure resulting in the remarkable properties of the materials. magnified image
H. Gleiter (Wed,) studied this question.