A shutter system could then be used to physically separate {TAIL ~ the non affected molecules} taking advantage of this difference in {HEAD ~ velocity} 
A shutter system could then be used to physically separate { TAIL ~ the non affected molecules } taking advantage of this difference in { HEAD ~ velocity }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD