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Fourier analysis methodology

Instead of this methodology, we have chosen to use Fourier analysis of the entire peak shape. By this procedure all of the above problems are eliminated. In particular, we focus on the cosine coefficients of the Fourier series representing a peak. The instrumental effects are readily removed, and the remaining coefficient of harmonic number, (n), A, can be written as a product ... [Pg.385]

An alternative approach is to impose random fluctuations upon the flow and then use Fourier analysis of the resultant current or potential fluctuations to obtain the transfer function. MartemYanov and Grafov [17, 87, 88] used a particularly simple method employing a paddle stirrer to generate a turbulent flow, with a uniform spectrum of fluctuations over the frequency range (<100 Hz). This methodology was termed hydroelec-... [Pg.416]

Alternative modulation functions and data analysis procedures have been applied in MTDSC. Different instrument manufacturers have applied square wave or saw-tooth modulation, coupled with Fourier transform analysis methodologies. Alternative modulation functions provide some additional advant ages - for example, a square wave function ensures that a steady state is achieved over an isothermal plateau since the signal during such a period is the nonreversing contribution. The amplitude provides a measure of the reversing signal. However, there are... [Pg.4758]

Although most modem particle characterization methods are developed, validated and presumably used for spherical particles or equivalent spherical particles, real particles are rarely such ideal. In many instances, particle shape affects powder packing, bulk density, and many other macroscopic properties. Shape characterization of particulate systems only scatters in the literature [60], since there are hardly any universal methodologies available. Several methods exist that use shape coefficients, shape factors, Fourier analysis, or fractal analysis to semi-quantitatively describe shape [Ij. [Pg.46]

STM, coincidently developed at around the same time as the discovery of QCs [158], provides real-space images of surfaces that can provide a wealth of information about surface morphology and fine structure. The lack of periodicity in QCs means that analysis methodologies centered around the superposition of surface lattices or meshes are inapplicable this has been compensated for in the case of QCs through the extended use of other image analysis tools, such as autocorrelation, Fourier transforms, and Fourier filtering, and the superposition... [Pg.356]

To benefit general readers, the discussion has been limited to methodologies that are accessible to nonspecialists and that can be carried out on commercially available spectrometers without special modifications. The chapter illustrates the principles of mass spectrometry by demonstrating how various techniques [MALDI, ESI, Fourier transform ion cyclotron resonance (FT-ICR), ion traps, and tandem mass spectrometry (MS-MS)] work. It also provides examples of utilizing mass spectrometry to solve biological and biochemical problems in the field of protein analysis, protein folding, and noncovalent interactions of protein-DNA complexes. [Pg.8]

In the X-ray analysis of a protein crystal structure, solvent molecules appear as spheres of electron density in difference Fourier maps calculated at the end of a refinement. In a strict sense, the electron density map exhibits preferred.s/tes of hydration which are occupied by freely interchanging solvent molecules. This electron density is well defined for the tightly bound solvent molecules and can be as spurious as just above background for ill-defined molecules which exhibit large temperature factors and/or only partly occupied atomic positions. Since these two parameters are correlated in least-squares refinement, this gives rise to methodological problems. [Pg.459]

After their isolation by chromatographic techniques (anion-exchange chromatography, size exclusion, etc.), different analytical methodologies have been used to identify and quantify the polysaccharides in wine the most commonly used being the traditional methylation analysis followed by GC-MS (Doco and Bril-louet 1993). Polysaccharides have also been determined after solvolysis with anhydrous methanol containing HCl by GC-MS of their per-G-trimethylsilylated methyl glycosides (Vidal et al. 2003). Other techniques such as Fourier transform infrared spectroscopy (FTIR) have been more recently proposed (Coimbra et al. 2002,2005 Boulet et al. 2007). [Pg.244]

This paper summarizes a series of experiments directed to the development of Fourier transform infrared spectroscopic (FT-IR) techniques for monitoring the events that occur when blood contacts the surface of a biomedical device. Special emphasis is placed on the methodology used for quantification and compositional analysis of protein adsorption from complex protein mixtures in aqueous solutions. [Pg.362]

For completeness, we mention that there are several other methodologies for the characterization of the shape of molecular surfaces from local geometric features. The use of Fourier shape descriptors is an interesting alternative, adapted recently for the analysis of macromolecular surfaces. [Pg.228]

The first efforts towards real-time and in-line monitoring of CO2 absorption processes focused on the use of Fourier transform infrared (FTIR) spectroscopy in combination with a multivariate model. Geers et al. (3) successfully applied this methodology to a solvent consisting of an equimolar solution of p-alanine and potassium hydroxide. They predicted the concentrations of the amine, of absorbed CO2 and SO2, and also included the effect of NO2 in their analysis. [Pg.381]


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