Micromeritics Gemini VII 2390a, Operator'S Manual, Page: 143 / 426

Gemini VII Report Options Files
239-42828-01 - Dec 2012 5-33
Alpha-S Method
The Alpha-S plot converts the standard adsorption isotherm into a dimensionless isotherm using the
quantity adsorbed at a relative pressure of 0.4. In the
Selected Reports
list box, highlight
Alpha-S
Method
, then click
Edit
.
One predefined curve is shipped with the analysis program and is located in the Reference directory.
Use the table to enter relative pressure and the alpha-s values.
Field or Button Description
Open button
To import values from an existing thickness curve (.ALS ASCII file), click
Open
, and select the file containing the values.
The table to be imported must be saved as ASCII text with a .
ALS
extension. It must have a two-column format with the relative pressures in
the first column and the alpha-s values in the second column. Columns
must be separated by a space or a tab.
Relative pressure

range text boxes
Enter the pressure range when calculation assignments are not used.
Fitted Alpha-S range
text boxes
Enter minimum and maximum relative pressures to determine the fit.
Ref. surface area

text box
Enter the surface area from the reference curve. This value is used to
calculate the sample surface area.