The first metallic electrode comprises copper or {HEAD ~ an alloy} of nickel and {TAIL ~ copper} 
of
The first metallic electrode comprises copper or { HEAD ~ an alloy } of nickel and { TAIL ~ copper }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH TAIL TAIL TAIL TAIL TAIL