{HEAD ~ The cell densities} of the flow through honeycomb substrate 200 and the wall flow particulate filter 300 may or may not be the same, where cell density is the number of channels per cross sectional area of {TAIL ~ the honeycomb substrate} 
{ HEAD ~ The cell densities } of the flow through honeycomb substrate 200 and the wall flow particulate filter 300 may or may not be the same , where cell density is the number of channels per cross sectional area of { TAIL ~ the honeycomb substrate }
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