{HEAD ~ A mixture} of silane, phosphine and boron trichloride is flowed into {TAIL ~ the reactor tube} through a first pair of silane injectors 
is flowed into
{ HEAD ~ A mixture } of silane , phosphine and boron trichloride is flowed into { TAIL ~ the reactor tube } through a first pair of silane injectors
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH