Meaning of "as applied to"
Hi everyone, I've just come across of the phrase above. I guess it's not the same as "applied to", isn't it? So, can you guys kindly explain to me what "as applied to" means, please?
This is the sentence including the phrase:
"A very important difference between x-ray diffraction as applied to 3D bulk solids and electron diffraction as applied to surfaces is that for the latter case translational symmetry perpendicular to the surface does not exist."
Many thanks in advance.