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