2. Input n-butanol concentration and corresponding maximum pressure difference in data columns A[X] and B[Y] respectively;
3. Click the right mouse button in the blank space and click "Add New Column" to add a new data column C [Y];
4. Right-click the data column of C[Y] and click "Set column value". In the dialog box, enter the calculation program to calculate the surface tension of n-butanol: "(0.0728/566)*col(B)", enter it and click "OK" to get the surface tension of different n-butanol solutions in C[Y]. Note that in the formula "(0.0728/566)/col(B)", "0.0728" is the surface tension of water at the experimental temperature, and the data of each group may be different, and "566" is the maximum pressure difference of water measured, which is also different in each group. Just input the data measured by your group for calculation.
5. Select column C[Y] and click "Analysis → Nonlinear Curve Fitting → Advanced Fitting Tool" to open the data fitting dialog box.
6. Click Function → New in the dialog box to create a new fitting function.
7. Enter the fitting function you specified in the Example box: "y = p1-p2 * ln (1+p3 * x)", set the Number of Parameters to 3 and the Form to Equation.
8. Establish
Click Operation → Dataset to open the parameter description dialog box. Click the Y variable in the list box at the top of the dialog box, and then click Data 1 -c in the Available Data Columns list box; Click the Assign command button. That is, the y variable corresponds to the Data 1-C sequence. You can also specify that the x variable corresponds to the Data 1-A sequence.
9. Click Operation → Fitting to open the curve fitting dialog box. Set the initial value of "P3 P2 p 1" to "1". Click the "100 Iter" button for 2 ~ 5 times until the parameter value remains unchanged. At the same time, the fitted curve will appear in the drawing box. Click "Finish" and the fitting parameter values will appear in the curve dialog box (see also the data box below the curve, giving the values of P 1, P2, P3, and bringing in y = p1-p2 * ln (1+P3 * x) to get the fitting function, where y is the surface tension.
10. Calculate the slope dγ/dc corresponding to each point of the curve. After the fitting curve is obtained by the above method, right-click the drawing box "1" to open the shortcut menu, and click the "NLSF" data at the bottom. Click "Different" in "Calculus" in "Analysis", and the drawing box "Deriv" of the relationship curve between dγ/dc and C will appear.
1 1. Double-click the curve on the derivative of the drawing box to display the Drawing Details dialog box, and click Sheet at the bottom of the Drawing Details dialog box. The "derivative 1-NLSF 1-b derivative" dialog box of relevant data on the relationship curve appears, that is, "a (x)"-concentration and "derivative of NLSF 1B(y)NLSF 1-b"-surface tension versus concentration on the fitting curve.
12. Right-click the blank on the right side of the table "Derivative of 1-NLSF 1-b" to open the shortcut menu and click Add.
New column ",that is, a new column appears; Right-click the top column of a blank column to open the shortcut menu, and then click Set Column Value to open the Set Column Value dialog box. Enter the formula in the text box:-(col (a) * col (nlsf1b))/(8.314 * 293.15).
13. Right-click in the blank on the right side of the "Derivative 1-NLSF 1-b Derivative" table to open the shortcut menu and click "Add".
New column ",that is, a new column appears; Right-click the top column of a blank column to open the shortcut menu, and then click Set Column Value to open the Set Column Value dialog box. Enter the formula: col( A)/col(B) and click OK to obtain the concentration/adsorption capacity.
14. Select C( Y), right click, and then click "Drawing → Scatter Diagram" to display the relationship curve between concentration/adsorption capacity and concentration; Click "Analysis → Fitting-Pad".
Linear fitting is performed, and the fitting data is displayed in the data frame below the curve. Finally, the saturated adsorption capacity can be obtained from the slope of the straight line, and the cross-sectional area of ethanol molecules can be calculated.
15. Data replication. Minimize the window, and then click the dialog box to view the data and graphics. When copying a chart, click Edit → Copy Page, and then click Paste in the word document.