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Giới thiệu phần mềm Peakfit và bộ công cụ phần mềm của ssi-academic.com 11 Months ago
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PeakFit Release Notes
1. PeakFit's Parameter Constraints
The Fit Preferences option contains built-in parameter constraints which are based upon a percentage variation from the values defined by the initial placement of the peaks. The default values for these constraints are quite rigid, and best serve spectral or chromatographic data with a large number of well defined peaks. If you see repeated non-zero values in the Constraints field during fitting, you may need to open these constraints or cautiously disable them altogether.
2. Fitting in Background
To have the peak fit performed in the background, simply minimize either the Numeric Fitting or Graphical Fitting window. Since PeakFit uses a separate and lower priority fitting thread, foreground performance should not suffer in any way.
3. Deleting Peaks Directly
In the AutoFit Peaks options, you can now delete a peak directly simply by double clicking its primary anchor. The procedure described in the documentation for deleting a peak, that of right clicking the peak's primary anchor and then left clicking the Delete Peak button in the popup dialog, can also be used.
4. Mixtures of Positive and Negative Amplitude Peaks
PeakFit can now automatically and accurately place mixtures of positive and negative amplitude peaks. This capability is present within the AutoFit Peaks I Residuals option. Simply check Allow Negative. When negative amplitude peaks are permitted, the option to automatically add the positive residual peaks is disabled. Individual residuals peaks can still be added by clicking in the residuals plot near the center position of the desired peak. You may need to pre-subtract the baseline or use the linear progressive baseline option since the constant zero second derivative procedure fails when negative amplitude peaks are present.
5. Partial Rescans
When you have made custom peak placements in one of the AutoFit Peaks options, it is possible to change control panel settings without experiencing a complete rebuild of the peaks. When custom adjustments are detected, you are presented the option of either a Full or Partial scan. The full scan will clear all custom adjustments. The partial scan will use the current peak count and positions as a basis for a new placement of peaks. Peaks other than the current default peak type are left completely alone in a partial scan.
6. Importing Process Data from AIA Files
AIA Chromatography files containing process data with valid retention times can be imported in any of the AutoFit Peaks options. The Read Scan Setup and Parameter Estimates option also offers the AIA CDF file type. Simply select the AIA file containing the peak analysis results you wish to import (PeakFit will use only the peak count and retention time values). The file containing the process data need not be the same as the data fitted, but retention times must be within the range of the data being fitted in order to be placed as peaks. When you change an option which causes a rescan to occur, you must select a Partial scan in order to preserve the imported peak count and positions. If Vary Widths or Vary Shape is checked, these retention times will be further refined by PeakFit.
7. Importing Peak Locations from an ASCII File
You may also create an ASCII file containing the peak locations where you wish PeakFit to place peaks. This is available in all three AutoFit Peaks options. The Read Scan Setup and Parameter Estimates option also offers an ASCII TXT file type for importing this external list of peak positions. Use any ASCII text editor to create the file, or you may wish to generate the file from a custom program. Simply list the peak apex positions one per line. These positions must be within the range of the data being fitted. Whenever a rescan occurs, you must select a Partial scan in order to preserve the imported peak count and positions. If Vary Widths or Vary Shape is checked, these peak location values will be refined by PeakFit.
8. Non-Parametric Digital Filter with Quadratic Model
When you are using PeakFit's Non-Parametric Digital Filter with the quadratic model, it is recommended that you use a data window of at least 5 points. With noisy data, instabilities can arise when the minimum data window of 4 points is used.
9. Right Mouse Zoom-In Reset
Clicking the right mouse in a PeakFit Graph, away from a data point or peak anchor, will now result in only a clearing of the current zoom-in. A full reset of default scaling no longer occurs.
10. Analytic Areas in Numeric Summary
An analytic area is one which has a closed form solution. PeakFit has closed form analytic area formulas for most of its peaks functions and these are reported in the Measured Values section of the Numeric Summary. The exceptions are the Gaussian-Lorentzian Cross-Product function, the Pearson IV function, the Symmetric Double Cumulative, the Asymmetric Double Sigmoidal, and the Asymmetric Double Cumulative. For these functions, the Numeric Summary reports "Unknown" for the analytic area and analytic area percentages are omitted for all peaks. For these functions, you will need to rely on the areas from numeric integration. Unless a peak has very wide tails which extend beyond the X-range of the data, the analytic and numeric integration areas will be essentially equivalent.
11. Adding Numeric Summary to Printed Output
This option is available when Printing Graphs in both fixed and custom portrait modes. The numeric summary is printed immediately below the graph. With 8 or fewer peaks, both fitted parameters and an abbreviated measured values are reported. For more than 8 peaks, only the measured values are printed. Font scaling is automatic to fit within the specified area. This option will only be available within PeakFit's Review.
12. Line Width in Printed Output
When Printing Graphs to high resolution output devices, the single width lines used for drawing peaks may appear too light. These lines can be darkened by increasing the line width. Since this width cannot be effectively represented within the limited screen resolution, the print preview will not reflect this line width setting.
13. Fitting Gaussian and Lorentzian Derivatives
You may now numerically place first or second derivatives of Gaussian or Lorentzian peaks. These functions are only available using the right mouse popup selection. These are listed as D1(Gauss Amp), D2(Gauss Amp), D1(Lor Amp), and D2(Lor Amp). The functions must be placed strictly by the numeric values of the parameters of the underlying Gaussian or Lorentzian. Automatic placement and graphical adjustment are not available.
As an alternative to fitting derivatives, you may wish to consider the value of using PeakFit's Cumulative Area option to first integrate the data and then fit the peaks directly using PeakFit's automation. Since noise in derivatives often produces unusual trends in the integrated baseline, prior to fitting you may wish to use PeakFit's non-parametric procedure in the AutoFit Baseline option. By activating only those points judged to represent a true baseline, the non-parametric model can effectively fit and remove this type of baseline.
The measured values section of the Numeric Summary will report an analytic area based on the underlying peak, rather than the derivative. Note that most of the measured values are valid only for peak-type data and will have no meaning when fitting derivatives.
14. Excel 97, 2000, XP Support
Starting in v4.06, Excel 97, 2000, and XP import support is available.
15. SPSS v8-v11 Support
Starting with v4.10, SPSS v8-v11 import support is available.
16. Systat v7-v10 Support
Starting with v4.10, Systat v7-v10 import support is available.
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