Therefore, a proper replacement can be achieved at {HEAD ~ the latter step S151} by making {TAIL ~ the profiles} at the line L side coincide together 
by making
Therefore , a proper replacement can be achieved at { HEAD ~ the latter step S151 } by making { TAIL ~ the profiles } at the line L side coincide together
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH