Unlike the prior art systems, the instant invention imposes {HEAD ~ no limits} on {TAIL ~ cathode size} or shape 
on
Unlike the prior art systems , the instant invention imposes { HEAD ~ no limits } on { TAIL ~ cathode size } or shape
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH