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