Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Shape Quantitation

In the present case, the obtained V/T dependencies of the nonlinear susceptibilities and those from Ref. 93 are qualitatively the same. Their most typical feature is the double-peak shape. Quantitatively, however, the... [Pg.493]

The measurement of peak potentials during LSV neglects much of the information present in the wave. For purely kinetic waves, the wave shape is dependent upon the mechanism of the process and can be used to distinguish between mechanisms. Although conclusions can be drawn by the direct comparison of the shape of the current-potential curve with theoretical data, such a comparison is subjective. Several procedures have been developed to analyse LSV wave shapes quantitatively for mechanism analysis. [Pg.170]

Qualitative terms [10] may be used to give some indication of particle shape but these are of limited use as a measure of particle properties ( Fable 2.4). Such general terms are inadequate for the determination of shape factors that can be incorporated as parameters into equations concerning particle properties where shape is involved as a factor. In order to do this, it is necessary to be able to measure and define shape quantitatively. [Pg.70]

Bearing these considerations in mind, nonetheless, shape quantitation presents a challenge well worth the effort. The potential value of shape quantitation is clearly demonstrable in physical and biological studies where this attribute is influential. Accordingly, we have addressed this problem and have contributed one possible approach to its solution. [Pg.392]

Equilibrium dynamics of vesicles comprises the dynamical fluctuations around locally stable mean shapes. Quantitatively, such fluctuations have been studied for quasi-spherical vesicles [29,61] and for prolate shapes in the vicinity of the budding transition [33]. A nontrivial example of dynamical equilibrium fluctuations has been observed at the prolate-oblate transition [62]. As the activation energy between the two locally stable shapes is just a few k T, occasionally thermal fluctuations are large enough to drive the vesicle into the other minimum. This system thus constitutes one of the few examples showing a thermally induced macroscopic bistability. [Pg.83]

The purpose of the nondestructive control consists in detecting local modifications of the material parameters which, by their presence can endanger the quality of the half-finished or finished products. The electromagnetic nondestructive control permits to render evident surface and subsurface discontinuities in the electroconductive material under test. The present tendency of this control is to pass from a qualitative evaluation (the presence or absence of the material discontinuities which give at the output of the control equipment a signal higher or at least equal to that coming from a standard discontinuity whose shape and severity has been prescribed by the product standards) to a quantitative one, which enables to locate as exactly as possible the discontinuity and to make predictions over its shape and severity. [Pg.373]

The Champ-Sons model is a most effieient tool allowing quantitative predictions of the field radiated by arbitrary transducers and possibly complex interfaces. It allows one to easily define the complete set of transducer characteristics (shape of the piezoelectric element, planar or focused lens, contact or immersion, single or multi-element), the excitation pulse (possibly an experimentally measured signal), to define the characteristics of the testing configuration (geometry of the piece, transducer position relatively to the piece, characteristics of both the coupling medium and the piece), and finally to define the calculation to run (field-points position, acoustical quantity considered). [Pg.737]

Figure Bl.16.22 shows a stick plot siumnary of the various CIDEP mechanisms and the expected polarization patterns for the specific cases detailed in the caption. Each mechanism clearly manifests itself in the spectrum in a different and easily observable fashion, and so qualitative deductions regarding the spin multiplicity of the precursor, the sign of Jin the RP and the presence or absence of SCRPs can innnediately be made by examining the spectral shape. Several types of quantitative infonnation are also available from the spectra. Figure Bl.16.22 shows a stick plot siumnary of the various CIDEP mechanisms and the expected polarization patterns for the specific cases detailed in the caption. Each mechanism clearly manifests itself in the spectrum in a different and easily observable fashion, and so qualitative deductions regarding the spin multiplicity of the precursor, the sign of Jin the RP and the presence or absence of SCRPs can innnediately be made by examining the spectral shape. Several types of quantitative infonnation are also available from the spectra.
Obtaining high-quality nanocry stalline samples is the most important task faced by experimentalists working in tire field of nanoscience. In tire ideal sample, every cluster is crystalline, witli a specific size and shape, and all clusters are identical. Wlrile such unifonnity can be expected from a molecular sample, nanocrystal samples rarely attain tliis level of perfection more typically, tliey consist of a collection of clusters witli a distribution of sizes, shapes and stmctures. In order to evaluate size-dependent properties quantitatively, it is important tliat tire variations between different clusters in a nanocrystal sample be minimized, or, at tire very least, tliat tire range and nature of tire variations be well understood. [Pg.2900]

Wlrile tire Bms fonnula can be used to locate tire spectral position of tire excitonic state, tliere is no equivalent a priori description of the spectral widtli of tliis state. These bandwidtlis have been attributed to a combination of effects, including inlromogeneous broadening arising from size dispersion, optical dephasing from exciton-surface and exciton-phonon scattering, and fast lifetimes resulting from surface localization 1167, 168, 170, 1711. Due to tire complex nature of tliese line shapes, tliere have been few quantitative calculations of absorjDtion spectra. This situation is in contrast witli tliat of metal nanoparticles, where a more quantitative level of prediction is possible. [Pg.2910]

Besides the aforementioned descriptors, grid-based methods are frequently used in the field of QSAR quantitative structure-activity relationships) [50]. A molecule is placed in a box and for an orthogonal grid of points the interaction energy values between this molecule and another small molecule, such as water, are calculated. The grid map thus obtained characterizes the molecular shape, charge distribution, and hydrophobicity. [Pg.428]

The smallest basis sets are called minimal basis sets. The most popular minimal basis set is the STO—3G set. This notation indicates that the basis set approximates the shape of a STO orbital by using a single contraction of three GTO orbitals. One such contraction would then be used for each orbital, which is the dehnition of a minimal basis. Minimal basis sets are used for very large molecules, qualitative results, and in certain cases quantitative results. There are STO—nG basis sets for n — 2—6. Another popular minimal basis set is the MINI set described below. [Pg.81]

In a titrimetric method of analysis the volume of titrant reacting stoichiometrically with the analyte provides quantitative information about the amount of analyte in a sample. The volume of titrant required to achieve this stoichiometric reaction is called the equivalence point. Experimentally we determine the titration s end point using a visual indicator that changes color near the equivalence point. Alternatively, we can locate the end point by recording a titration curve showing the titration reaction s progress as a function of the titrant s volume. In either case, the end point must closely match the equivalence point if a titration is to be accurate. Knowing the shape of a titration... [Pg.357]

The general shape of the contours resembles the corresponding curves for [77], which are shown in Fig. 9.4a. The contours for f/fQ and [77] differ in quantitative detail, however. [Pg.627]

This simple model illustrates how the fraction K and, through it, Vj are influenced by the dimensions of both the solute molecules and the pores. For solute particles of other shapes in pores of different geometry, theoretical expressions for K are quantitatively different, but typically involve the ratio of solute to pore dimensions. [Pg.647]

The design of smart materials and adaptive stmctures has required the development of constitutive equations that describe the temperature, stress, strain, and percentage of martensite volume transformation of a shape-memory alloy. These equations can be integrated with similar constitutive equations for composite materials to make possible the quantitative design of stmctures having embedded sensors and actuators for vibration control. The constitutive equations for one-dimensional systems as well as a three-dimensional representation have been developed (7). [Pg.465]

Currendy, the Bauer-McNett classification and the QS test are the most widely used fiber classification techniques. Whereas there are quaUtative relationships between QS and BMN, there is no quantitative correspondence. It is readily understood that these standard tests do not provide accurate definition of the fiber lengths the classification also redects the hydrodynamic behavior (volumes) of the fibers, which, because of thek complex shapes, is not readily predictable. [Pg.353]

The color and constitution of cyanine dyes may be understood through detailed consideration of their component parts, ie, chromophoric systems, terminal groups, and solvent sensitivity of the dyes. Resonance theories have been developed to accommodate significant trends very successfully. For an experienced dye chemist, these are useful in the design of dyes with a specified color, band shape, or solvent sensitivity. More recendy, quantitative values for reversible oxidation—reduction potentials have allowed more complete correlation of these dye properties with organic substituent constants. [Pg.389]

In this work, we determine constraints on the dimensionless parameters of the system (dimensionless electrode widths, gap size and Peclet number), first qualitatively and then quantitatively, which ensure that the proposed flow reconstmction approach is sufficiently sensitive to the shape of the flow profile. The results can be readily applied for identification of hydrodynamic regimes or electrode geometries that provide best performance of our flow reconstmction method. [Pg.127]

The kinetics of the processes of oxidation of these complex sulphides have not been established quantitively, but the rate of advance of the oxides into sulphide particles of inegular shapes were always linear. This suggests tlrat the oxide films were rupmred during growth thus permitting the gas phase to have relatively unimpeded access to tire sulphide-oxide interface in all cases. [Pg.275]


See other pages where Shape Quantitation is mentioned: [Pg.115]    [Pg.11]    [Pg.449]    [Pg.404]    [Pg.410]    [Pg.202]    [Pg.202]    [Pg.115]    [Pg.11]    [Pg.449]    [Pg.404]    [Pg.410]    [Pg.202]    [Pg.202]    [Pg.701]    [Pg.309]    [Pg.1381]    [Pg.1399]    [Pg.1477]    [Pg.2522]    [Pg.603]    [Pg.433]    [Pg.932]    [Pg.116]    [Pg.443]    [Pg.168]    [Pg.96]    [Pg.548]    [Pg.30]    [Pg.274]    [Pg.463]    [Pg.510]    [Pg.533]    [Pg.254]    [Pg.1826]    [Pg.353]   


SEARCH



Quantitative Shape-Activity Relations

Quantitative Shape-Activity Relations QShAR)

© 2024 chempedia.info