Spectral curve fitting

Data for 31 elements can be rapidly determined but result in some interferences between elements. No spectral curve fitting or matrix (ZAF) correction schemes were used in this survey study. ZAF correction does not seem to markedly aid the cluster analysis... 

It is worth noting that (7.10) is also applicable to other characteristic spectral positions such as the interference peak and the center point of the interferogram. In addition, curve fitting of the interference fringe can also improve the measurement accuracy20. 

Dr. Spijkerman No, that will not do. The spectral lines should be resolved otherwise manual and computer curve fitting could give diflFer-ent results. 

The number of bands present in a spectral window and their centers of symmetry are pre-requisites to other signal processing procedures i. e. curve fitting. For in situ spectroscopic reaction studies, a set of tracks can be assigned which specify the centers of symmetry for all the bands. Since the bands move as a function of composition, the tracks in a matrix or AF %xv drift. 

The Pearson VII model contains four adjustable parameters and is particularly well suited for the curve fitting of large spectral windows containing numerous spectral features. The adjustable parameters a, p, q and v° correspond to the amplitude, line width, shape factor and band center respectively. As q —the band reduces to a Lorenzian distribution and as q approaches ca. 50, a more-or-less Gaussian distribution is obtained. If there are b bands in a data set and... 

Fig. 37 Isolated set of infrared absorption lines in the infrared spectral region (a) with a smooth curve fitted to the base line and (b) adjusted to zero base line.

Data obtained both by integration and least-squares curve fitting are compared in order to reveal possible differences in the quality of data produced. Integration over a spectral region takes only the time needed to input the information, whereas curve fitting may take 30 min to resolve the component bands be-... 

Figure 3. Spectral area for aliphatic CH3 groups at 2956 ctn-1 (curve fitting) vs. calorific value.

Incomplete resolution of gauche CD rocking modes along with the occasional presence of incompletely subtracted, weak spectral features arising from cholesterol or Gramicidin D, made curve fitting for quantitative analysis of band intensities necessary. 

The ultimate objective of remote reflectance spectral measurements is to obtain quantitative estimates of the modal mineralogy of unexplored surfaces of the Moon and, indeed, other terrestrial planets. This necessitates difficult and elaborate spectrum-curve fitting procedures, which has been the focus of detailed research (e.g., Roush and Singer, 1986 Clouds et al., 1986 Mustard... 

The analysis of spectral shape of XANES not only for Al, but also for other absorbing atoms using a curve fitting method will be therefore helpful to understanding not only the search of structural transition process, but also chemical species appearing in the process. 

Computations are completed through an iteration process. There is no exact tristimulus match, but a best-fit spectral curve match is calculated. This is not a selective spectral match. Formulations are done using a spectral matching routine. 

When P > 3, exponential curve-fitting procedures for the WSGG spectral model become significantly more difficult for hand computation but are quite routine with the aid of a variety of readily available... 

If two or more transitions overlap, the quantitative interpretation of the MCD spectrum becomes much more difficult and computational curve fitting that requires simple band shapes is needed. Often, the vibrational structure of the MCD spectrum, which will in general be different from the one in the absorption spectrum, will be so pronounced that this assumption is not fulfilled. Although uncommon, there are some cases known where some sections of the vibrational envelope associated with a single electronic transition are positive and some negative. Thus, the appearance of both positive and negative MCD peaks in a spectral region does not necessarily mean that... 

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