Before irradiation or heating, {HEAD ~ the silver film} provides {TAIL ~ a low resistance electrical connection} between the two conductors 
provides
Before irradiation or heating , { HEAD ~ the silver film } provides { TAIL ~ a low resistance electrical connection } between the two conductors
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH