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Basic Remarks

The basic remark is that linearity of the macroscopic law is not at all the same as linearity of the microscopic equations of motion. In most substances Ohm s law is valid up to a fairly strong field but if one visualizes the motion of an individual electron and the effect of an external field E on it, it becomes clear that microscopic linearity is restricted to only extremely small field strengths.23 Macroscopic linearity, therefore, is not due to microscopic linearity, but to a cancellation of nonlinear terms when averaging over all particles. It follows that the nonlinear terms proportional to E2, E3,... in the macroscopic equation do not correspond respectively to the terms proportional to E2, E3,... in the microscopic equations, but rather constitute a net effect after averaging all terms in the microscopic motion. This is exactly what the Master Equation approach purports to do. For this reason, I have more faith in the results obtained by means of the Master Equation than in the paradoxical result of the microscopic approach. [Pg.76]

Before we go into individual detail on the development of the Community exhaust-gas standards, it would seem appropriate to make one or two basic remarks concerning the relationship between the Commission of the European Communities and the United Nations Economic Commission for Europe (ECE), Geneva as regards vehicle regulations. [Pg.71]

A. Amann, E. Scholl, and W. Just Some basic remarks on eigenmode expansions of time-delay dynamics, Physica A 373, 191 (2007). [Pg.180]

A similar approach was followed by Monflier and coworkers [94], who sulfonated biphenyl phosphines and screened the resulting BiphTS ligands in the cobalt-catalyzed aqueous biphasic hydroformylation. These phosphines have a solubihty in water of 1.0kgl . Compared to TPPTS, BiphTS ligands are more basic. Remarkably, PfBiPhljTS possesses a basicity similar to that of PPhj, which means that the deactivating effect of the sulfonate groups is fully suspended. [Pg.99]

The mobility of the proton in position 2 of a quaternized molecule and the kinetics of exchange with deuterium has been studied extensively (18-20) it is increased in a basic medium (21-23). The rate of exchange is close to that obtained with the base itself, and the protonated form is supposed to be the active intermediate (236, 664). The remarkable lability of 2-H has been ascribed to a number of factors, including a possible stabilizing resonance effect with contributions of both carbene and ylid structure. This latter may result from the interaction of a d orbital at the sulfur atom with the cr orbital out of the ring at C-2 (21). [Pg.31]

Fluorides. Most woddwide reductions in dental decay can be ascribed to fluoride incorporation into drinking water, dentifrices, and mouth rinses. Numerous mechanisms have been described by which fluoride exerts a beneficial effect. Fluoride either reacts with tooth enamel to reduce its susceptibihty to dissolution in bacterial acids or interferes with the production of acid by bacterial within dental plaque. The multiple modes of action with fluoride may account for its remarkable effectiveness at concentrations far below those necessary with most therapeutic materials. Fluoride release from restorative dental materials foUow the same basic pattern. Fluoride is released in an initial short burst after placement of the material, and decreases rapidly to a low level of constant release. The constant low level release has been postulated to provide tooth protection by incorporation into tooth mineral. [Pg.494]

It is important to emphasize that, especially in process measurements, radiation can have an essential influence on the wet bulb temperature, and therefore generally the wet bulb temperature is dependent on the mea,surement device and the method of measurement. If the airflow is very low, the radiation can have a remarkable contribution in addition to the convective heat transfer. Basically, an equation analogous to Eq. (4.138) can be empirically determined for each wet bulb temperature and method of measurement. [Pg.91]

The remarkable activating influence of the dialkylaminoalkyl side-chain was still shown when the harmol nucleus was replaced by other basic nuclei or even by a simple substituted amino-group, and out of an extensive series of compounds of the general formula (D) aK-tetra-n-amyldiamino-M-decane proved to be the most active. [Pg.403]

The mechanism inevitably involves the loss of water and, remarkably, methane. The yields are usually low due to the high temperatures required for this transformation to occur. If the 1,2-dihydroquinoline is isolated the aromatization can be performed in a separate step under acidic or basic conditions. ... [Pg.487]

In dry air the stability of zinc is remarkable. Once the protective layer of zinc oxide formed initially is complete, the attack ceases. Even under under normal urban conditions, such as those in London, zinc sheet 0 -8 mm thick has been found to have an effective life of 40 years or more when used as a roof covering and no repair has been needed except for mechanical damage. The presence of water does, of course, increase the rate of corrosion when water is present the initial corrosion product is zinc hydroxide, which is then converted by the action of carbon dioxide to a basic zinc carbonate, probably of composition similar to ZnCOj 3Zn(OH)2 . In very damp conditions unprotected zinc sometimes forms a loose and more conspicuous form of corrosion product known as wet storage stain or white rust (see p. 4.171). [Pg.816]

In this contribution, we review our recent work on disordered quasi-one-dimen-sional Peierls systems. In Section 3-2, we introduce the basic models and concepts. In Section 3-3, we discuss the localized electron stales in the FGM, while, in Section 3-4, we allow for lattice relaxation, leading to disorder-induced solitons. Finally, Section 3-5 contains the concluding remarks. [Pg.361]

It is remarkable that the magnitude of trapping is comparable to that in a system devoid of disorder. In fact, the critical concentration above which the effect of traps becomes noticeable is the same, i.c. In c, EJkT, which follows from Eq. (12.17). The basic difference between a disordered and a disorder-free system is... [Pg.524]


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