What the type of my sample and why hysteresis loop at high relative pressure in N2 ads-des isotherm?

 how calculate the pore size of the sample  the bet sample 2 920 m2/g and sample 1  83 m2/g  and total volume for sample 2  0,59 cm3/g amd sample one 0.39 cm3/g 

01 January 1970 5,665 1 View