{HEAD ~ The method} 2, wherein {TAIL ~ the width} of the opening portion of the core partition w is changeable 
wherein
{ HEAD ~ The method } 2 , wherein { TAIL ~ the width } of the opening portion of the core partition w is changeable
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH