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Subtraction method definition

It is only since 1980 that in situ spectroscopic techniques have been developed to obtain identification of the adsorbed intermediates and hence of reliable reaction mechanisms. These new infrared spectroscopic in situ techniques, such as electrochemically modulated infrared reflectance spectroscopy (EMIRS), which uses a dispersive spectrometer, Fourier transform infrared reflectance spectroscopy, or a subtractively normalized interfacial Fourier transform infrared reflectance spectroscopy (SNIFTIRS), have provided definitive proof for the presence of strongly adsorbed species (mainly adsorbed carbon monoxide) acting as catalytic poisons. " " Even though this chapter is not devoted to the description of in situ infrared techniques, it is useful to briefly note the advantages and limitations of such spectroscopic methods. [Pg.76]

Conventional implementations of MaxEnt method for charge density studies do not allow easy access to deformation maps a possible approach involves running a MaxEnt calculation on a set of data computed from a superposition of spherical atoms, and subtracting this map from qME [44], Recourse to a two-channel formalism, that redistributes positive- and negative-density scatterers, fitting a set of difference Fourier coefficients, has also been made [18], but there is no consensus on what the definition of entropy should be in a two-channel situation [18, 36,41] moreover, the shapes and number of positive and negative scatterers may need to differ in a way which is difficult to specify. [Pg.18]

Application of both these techniques to extensive sets of binary and ternary acqueous solutions of albumin, IgG and fibrinogen indicated that the "P" matrix estimates of unknown compositions were more accurate than those made using the "K" matrix method. The "P matrix also allowed quantitation inspite of the uncertainty in water subtraction and the definition of baselines. [Pg.370]

The entropy of a molecule is a measure of its disorder. Thus it is customary to express the entropy at any temperature in the ideal gaseous state Sj relative to the most ordered state, namely, the solid state at 0 K. With this definition, the entropy change for any reaction can be readily obtained by subtracting the sum of the values of Sj for the reactants from the sum for the products. In theory, it is also possible to estimate the entropy of formation A5f by using the values of iSt for the constituent elements, but no method is yet available for the purpose. [Pg.44]

Construction plane Rpj (Figure 4-16) is selected to define the location of creating a contour based feature. The contour is sketched in its final location by the method sketch in place. Construction by this method guarantees that all points of the contour he in the selected plane. Rp2 is defined to create a contour out of the existing shape. Line Rl is defined as a centerline for a subsequent shape modification. Rp acts as a split plane for the definition of the subtraction of volume Fy. A reference element may be created to control a shape such as a spine at sweeping. [Pg.131]

If we wish to verify, for instance, that hydrogen atoms are conserved by the first reaction, Eq. (2.47), we must count them in every term on either side, and then subtract these values there are four hydrogen atoms on both sides and subtraction yields zero. An equivalent but mathematically more elegant method is to use the entries of the stoichiometric matrix and the molecular matrix as follows we read —2 for the coefficient of H2 in the first row of the stoichiometric matrix and multiply by 2, the number of H atoms in H2 as indicated by the molecular matrix, and so on. The result is then (—2)(2)+(—1)(0)+(2)(2)+(0)(2)=0, which by definition is precisely the entry (1,1) of the product of the stoichiometric and molecular matrices SM. Similarly, the entry (//) of that product expresses the difference in atom counts of element j in reaction /. Consequently, we can express the balance of all reactions for all elements compactly as the zero matrix with all entries zero ... [Pg.22]


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See also in sourсe #XX -- [ Pg.157 , Pg.158 ]




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Subtracting

Subtraction method

Subtractive

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