The pressure of {HEAD ~ the tube} is maintained at {TAIL ~ 175 to 200 millitorr} while the reactant gases are flowed in 
The pressure of { HEAD ~ the tube } is maintained at { TAIL ~ 175 to 200 millitorr } while the reactant gases are flowed in
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH