{HEAD ~ The difference} in the contact potential measured before and after {TAIL ~ heating} provides an indication of the mobile ion concentration in the oxide layer 
measured before
{ HEAD ~ The difference } in the contact potential measured before and after { TAIL ~ heating } provides an indication of the mobile ion concentration in the oxide layer
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH