Techniques data processing

Instrumentation and data processing techniques for systems employing dynamic light scattering for the examination of fine particle motion are currently under development. 

With the appropriate fiber-optic probe and data processing techniques, UV-vis spectroscopy may be used to determine the optical thickness of a transparent thin film. It is possible to simultaneously measure thickness of different layers in a multilayer structure as long as each layer falls within the analysis range of the instrument. Typically, this means layers in the 0.5-150/rm range. A further constraint on this technique is that the layer structure of the film must be smooth on the scale of the spot size of the fiber-optic probe. Neighboring layers must have different indices of refraction in order for them to appear as distinct layers to the analyzer. 

In some cases, many different spectra (or chromatograms) of the same object are available. For inhomogenous objects, for example, several samples of different constitution can be taken. This allows to apply multivariate data processing techniques. When the signals of the compounds in the sample are specific and linearly additive, the number of compounds which contribute to the signal, can be determined by a Principal Components Analysis (PCA) " (see Sect. 3.2.1). Without knowing the identity of all compounds, which are present and without knowing their spectra, a calibration by partical least squares (PLC) allows to quantify the compounds of interest. 

Data Processing Techniques Using Digitized Infrared Spectra.. 97... 

The data manipulating capability of a computerized infrared spectrometer allows the spectroscopist to delve more deeply into the structural origin of the infrared absorptions by using data processing techniques to purify, manipulate, and correlate the spectra. If one can systematically vary the relative amounts of various structural contributions, absorbance subtraction can be used to isolate the spectral contributions of the structural components. 

The intense absorption of water over most of the infrared spectrum restricts the regions where aqueous solutions of carbohydrates can be usefully studied. Absorbance subtraction makes it possible to eliminate water absorbance and magnify the remaining spectral features to the limit of the signal-to-noise ratio. Many other data-processing techniques, such as the ratio method,4 the least-squares refinement,5 and factor analysis,6 should be of benefit in the study of carbohydrate mixtures. 

Data processing techniques are extremely useful in both pure EPR and electro-chemical-EPR studies. Details of the EPR computer interface are unique to each system and to the goals of each experiment. Since the theory and methodology of these digital operations are similar to those described elsewhere in this book, the discussion will not be reiterated here. There are numerous examples of signal averaging for kinetic measurements and for spectral accumulation using rapid scans. Short-lived species may be studied by these techniques. 

Ruan, Q., Peterman, S., Szewc, M. A., Ma, L., Cui, D., Humphreys, W. G., and Zhu, M. (2008). An integrated method for metabolite detection and identification using a linear ion trap/Orbitrap mass spectrometer and multiple data processing techniques Application to indinavir metabolite detection. J. Mass Spectrom. 43 251-261. 

In this chapter the application of multichannel IR detector arrays to mammalian tissue is discussed from a practical perspective. The major emphasis will be on the application of the technology to cervical cancer diagnosis focusing on sample preparation, instrumental parameters, data processing techniques and correlation with histology. The next part of the chapter focuses on the application of the technique to arthritis research by investigating the effect of specific antibodies that induce an arthritic type of response in bovine cartilage explants. In the final part of the chapter... 

It is also interesting to note that the limitations of most neutron systems lie not in the neutron source(s) but rather in the (gamma ray) detectors and subsequent data acquisition system. The obvious need is for development of detectors with higher rate capability and improved energy resolution. All modern digital data processing techniques have allowed significant improvement in the performance of conventional scintillation detectors with respect to rate and pileup rejection. 

Evaluation of Data Quality by Data Processing Techniques... 

Gillette PC, Lando JB, Koening JL (1985) A survey of infrared spectral data processing techniques In Ferraro JR, Basile LJ (eds) Fourier transform infrared spectroscopy -applications to chemical systems, Vol 4 Academic Press, New York, 1-47 Graham JA, Grim WM III, Fateley WG (1985) Fourier transform infrared photoacoustic spectroscopy of condensed-phase samples, In Ferraro JR, Basile LJ (eds) Fourier transform infrared) spectroscopy - applications to chemical systems, Vol 4 Academic Press, New York, 345-392... 

Xu, M., and Turton, R. (1997), A new data processing technique for noisy signals Application to measuring particle circulation times in a draft tube equipped fluidized bed. Powder Technol., 92,111-117. 

The data processing techniques so far discussed are basic and relatively simple. A more detailed treatment is not appropriate here but the subject of peak skimming and deconvolution will be discussed in the chapters on qualitative and quantitative analysis. 

Many of the health and environmental problems caused by arsenic and selenium were not predicted until recently because the distribution and behavior of arsenic and selenium in the environment were not sufficiently well known. Recent improvements have been aided by cost-effective analytical techniques and more powerful data-processing techniques, which have made it easier to prepare high-resolution geochemical maps. Also, modem digital data sets of geochemical and hydrochemical data are used increasingly in studies designed to estimate element speciation, bioavailability, and risk. 

No matter how advanced, every numerical data processing technique has intrinsic limitations, especially when the complexity of the data increases or when the required information is partially missing, as for example in single crystal diffraction from macromolecules and proteins or in powder... 

The fundamental simplicity of the powder diffraction experiment coupled with the sophistication of the available numerical data processing techniques and unsurpassed visual elegance, with which the results of the full profile refinement are represented, have transformed the powder diffraction technique into a modem and exceptionally important experimental tool in structure determination. Without a doubt, the powder method is poised to play a role in stmcture determinations with ever-increasing complexity. A recent example of the successful refinement of the sperm whale Physeter catodon) metmyoglobin stmcture from synchrotron powder diffraction data is an excellent illustration of how far the technique has been already advanced. ... 

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