Micromeritics Gemini VII 2390a, Operator'S Manual, Page: 316 / 426

Appendix C Gemini VII
C-22 239-42828-01 - Dec 2012
T
3
=
T
4
=
where
Cheng/Yang Correction
P
Po
-------
 
 
ln
G L
 
1
1

---
1
1

–
------------
 
 
ln – – =
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 capacity
(V
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 V
m
.
1
1
S
–
 
9
-------------------
1
1
S
+
 
9
-------------------
–
1
1
S
+
 
8
-------------------
1
1
S
–
 
8
-------------------
–
S
L d
0
–
L
--------------
=