At low pressure, {HEAD ~ the solid material} evaporates at {TAIL ~ a much lower temperature} than at atmospheric pressure 
evaporates at
At low pressure , { HEAD ~ the solid material } evaporates at { TAIL ~ a much lower temperature } than at atmospheric pressure
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH