In some embodiments, {HEAD ~ multiple portions} of surface 501 are simultaneously exposed to {TAIL ~ the electromagnetic radiation} 
are simultaneously exposed to
In some embodiments , { HEAD ~ multiple portions } of surface 501 are simultaneously exposed to { TAIL ~ the electromagnetic radiation }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL