{HEAD ~ The method} 1 wherein {TAIL ~ the particle} to be identified is immersed in a gas 
wherein
{ HEAD ~ The method } 1 wherein { TAIL ~ the particle } to be identified is immersed in a gas
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH