In certain embodiments, surface 501 is exposed to overlapping {HEAD ~ fields} of {TAIL ~ electromagnetic radiation} 
of
In certain embodiments , surface 501 is exposed to overlapping { HEAD ~ fields } of { TAIL ~ electromagnetic radiation }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL