{HEAD ~ A lock} in {TAIL ~ step} can prevent further changes in the structure of the porous multilayer 
in
{ HEAD ~ A lock } in { TAIL ~ step } can prevent further changes in the structure of the porous multilayer
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH