Micromeritics ASAP 2460 - Cheng;Yang Correction

ASAP 2460 Operator’s Manual Appendix C
246-42800-01 - Aug 2013 C-29
T
1
=
T
2
=
T
3
=
T
4
=
where
Cheng/Yang Correction
This factor corrects for the nonlinearity of the isotherm. It adds an additional term to the equations for
the different geometrics:
where
G(L) = one of the Horvath-Kawazoe equations given above
 = degree of void filling;  is estimated by first computing the monolayer capac-
ity (Q
m
) with the Langmuir equation over the range of data points from
relative pressure 0.02 to 0.2 or the maximum relative pressure included in the
Horvath-Kawazoe analysis.  is computed as the quantity adsorbed over Q
m
.
1
1 S–
3
-------------------
1
1 S+
3
-------------------
–
1
1 S+
2
-------------------
1
1 S–
2
-------------------
–
1
1 S–
9
-------------------
1
1 S+
9
-------------------
–
1
1 S+
8
-------------------
1
1 S–
8
-------------------
–
S
Ld
0
–
L
--------------
=
P
Po
-------


ln GL 1
1

---
1
1 –
------------


ln––=