A tip formed at the apex of said end conical portion has {HEAD ~ a radius} of {TAIL ~ curvature} of about 500 Å 
of
A tip formed at the apex of said end conical portion has { HEAD ~ a radius } of { TAIL ~ curvature } of about 500 Å
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH