A substrate is provided within {HEAD ~ a reaction chamber}, and {TAIL ~ a mixture} is also provided within the chamber 
A substrate is provided within { HEAD ~ a reaction chamber } , and { TAIL ~ a mixture } is also provided within the chamber
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH