A number of {HEAD ~ these alloys} can also be used as {TAIL ~ semi reflective layers} in optical storage devices such as DVD dual layer devices 
A number of { HEAD ~ these alloys } can also be used as { TAIL ~ semi reflective layers } in optical storage devices such as DVD dual layer devices
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH