This means that substantially all the catalyst provided in {TAIL ~ the cell wall} 23 can contribute to conversion reaction of {HEAD ~ exhaust gas} 
This means that substantially all the catalyst provided in { TAIL ~ the cell wall } 23 can contribute to conversion reaction of { HEAD ~ exhaust gas }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD