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Physical phenomena, introduction

As mentioned in the introduction, it seems useful to divide the discussion of the basic principles of nuclear magnetic resonance into two parts the physical phenomenon of... [Pg.90]

This book can serve as an introduction to students interested in learning the techniques used in developing mathematical models of physical phenomenon or it can furnish the background information to the experienced professional desiring to broaden his/her knowledge of polymers. [Pg.423]

Let us take the case of the relationship between efforts (the case of flows is similar and can be deduced from the present case). This relationship between dipole effort and effort difference is not as simple as one could expect. One must consider several aspects. The first one is the nature of the physical phenomenon requiring this link. Two phenomena are to be considered exchange by efforts and conservation of basic quantities. The first one has been seen in the beginning of this chapter, and the second one will be tackled soon after, thus necessitating a brief introduction. [Pg.183]

Correlation energy is ultimately a convenient container for all that escapes from first-order coulombic and polarization terms. See Bickelhaupt, F. M. Baerends, E. J. Kohn-Sham density functional theory predicting and understanding chemistry, Reviews in Computational Chemistry, Vol. 15, edited by K. B. Lipkowitz and D. B. Boyd, 2000, Wiley-VCH, New Yorkp.ll Is electron correlation (not defined in a statistical sense, but according to either the quantum chemical or the DFT definition) a true physical phenomenon It is a man-made concept, related to the introduction of a convenient trial wavefunction, that is useful for our communication and understanding. ... [Pg.115]

The reader is encouraged to use a two-phase, one spatial dimension, and time-dependent mathematical model to study this phenomenon. The UCKRON test problem can be used for general introduction before the particular model for the system of interest is investigated. The success of the simulation will depend strongly on the quality of physical parameters and estimated transfer coefficients for the system. [Pg.207]

The important phenomenon of exponential decay is the prototype first-order reaction and provides an informative introduction to first-order kinetic principles. Consider an important example from nuclear physics the decay of the radioactive isotope of carbon, carbon-14 (or C). This form of carbon is unstable and decays over time to form nitrogen-14 ( N) plus an electron (e ) the reaction can be written as... [Pg.110]

Surface roughness is also expected to result in depression of the capacitance semi-circle. This phenomenon, which is indeed apparent in both Figures 1 and 2, is, however, unrelated to surface area. Rather, it is attributable to surface heterogeneity, i.e. the surface is characterized by a distribution of properties. Macdonald (16) recently reviewed techniques for representing distributed processes. A transmission line model containing an array of parallel R/C units with a distribution of values is physically attractive, but not practical. An alternative solution is introduction of an element which by its very nature is distributed. The Constant Phase Element (CPE) meets such a requirement. It has the form P = Y0 wn... [Pg.639]

The present volume continues to provide an entire spectrum of interdisciplinary exposures to catalysis. As stated in the introduction to the first chapter by R. J. Madix, heterogeneous catalysis is a complex phenomenon to understand at the molecular level, and the key to understanding such processes lies in the ability to dissect the catalytic event into its separate components. This chapter describes physical and spectroscopic approaches to make the explanation of a variety of catalytic reactions on clean metal surface possible. [Pg.380]

The introduction of a plasticizer, which is a molecule of lower molecular weight than the resin, has the ability to impart a greater free volume per volume of material because there is an increase in the proportion of end groups and the plasticizer has a glass-transition temperature, T, lower than that of the resin itself A detailed mathematical treatment (2) of this phenomenon can be carried out to explain the success of some plasticizers and the failure of others. Cleady, the use of a given plasticizer in a certain application is a compromise between the above ideas and physical properties such as volatility, compatibility, high and low temperature performance, viscosity, etc. This choice is application dependent, ie, there is no ideal plasticizer for every application. [Pg.124]

As explained in the introduction, the polysilanes (and related polygermanes and poly-stannanes) are different from all other high polymers, in that they exhibit sigma-electron delocalization. This phenomenon leads to special physical properties strong electronic absorption, conductivity, photoconductivity, photosensitivity, and so on, which are crucial for many of the technological applications of polysilanes. Other polymers, such as polyacetylene and polythiophene, display electron delocalization, but in these materials the delocalization involves pi-electrons. [Pg.215]

The radiative heat-flux is generally treated separately from the other heat flux contributions because these physical phenomena are quite different in nature and involve unacquainted mathematics. Besides, the radiative contributions in the bulk of the fluid are limited because this flux is merely a surface phenomenon. Nevertheless, the radiative losses from solid surfaces are often significant in combustion and in particular chemical reactor processes. A brief introduction to the theory of thermal radiation is presented in sect 5.3.6. [Pg.44]

Thus the key point is to obtain the connections of the asymptotic solutions of Eq. (60) at - oo. The underlying mathematics to carry this out analytically is the Stokes phenomenon of asymptotic solutions of differential equations and is explained briefly in Sec. V. This is very important mathematics for the general semiclassical theory and various physical phenomena. It is interesting that the apparent small differences in q(%) of Eqs. (61) between the LZ and NT cases make a big difference mathematically and physically. The mathematical differences are not detailed here, but the physical differences are obvious, as pointed out in the Introduction. [Pg.492]

Chapter 2 is focused on physical principles of IPMCs. It starts with an introduction to the fundamentals of IPMCs, including the fabrication techniques, and then takes a careful look at the effect of electrodes on material behavior and actuation performance. Several novel approaches, including a fluorescence spectroscopic visualization method, are then used to yield unique insight into IPMC actuation behaviors, such as the back-relaxation phenomenon. More sophisticated configurations than a singlelayer bender are also discussed in this chapter. [Pg.2]


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See also in sourсe #XX -- [ Pg.609 ]




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