The surface layer is formed of {HEAD ~ metal crystals} belonging to {TAIL ~ a cubic system} with a plane of by Miller indices directed so as to form the slide surface 
belonging to
The surface layer is formed of { HEAD ~ metal crystals } belonging to { TAIL ~ a cubic system } with a plane of by Miller indices directed so as to form the slide surface
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH