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Uniformly positive

The effects of substituents in the -position to the radical center are mostly inductive in nature. Comparison of the RSE values for the ethyl radical (- 13.8 kj/mol) with those of the propyl, 2-hydroxyethyl, 2-fluoroethyl, and 2-chloroethyl radicals with RSE values of - 11.9, - 8.5, - 5.5, and - 6.7 kj/mol also indicates that electronegative substituents in the -position uniformly destabilize the radical center, the effect being larger for more electronegative substituents. Comparison of the RSE values of the 2-fluoro, 2,2-difluoro, and 2,2,2-trifluoroethyl radicals of - 5.5, + 3.0, and + 8.1 kj/mol also indicate that these effects can accumulate to yield overall destabilized radicals relative to the methyl radical. Even less favorable RSE values are found for positively charged substituents directly attached to the radical center such as - NH3+ (+ 18.3 kj/mol) or-SH2+ (+ 12.8 kj/mol) (Table 1). [Pg.184]

Fluidized-bed reactors are often rotationally symmetrical, and spraying takes place at different positions (uniform distribution of the sprayed liquid). Thus, a one-dimensional approach is used. [Pg.461]

The simplest electronic theory of metals regards a metallic object as abox filled with noninteracting electrons. (A slightly more elaborate picture is the jellium model in which the free electrons are moving on the backgroimd of a continuous positive uniform charge distribution that represents the nuclei.) The Drude model, built on this picture, is characterized by two parameters The density of electrons n (number per unit volume) and the relaxation time r. The density n is sometimes expressed in terms of the radius of a sphere whose volume is the volume per electron in the metal... [Pg.143]

I have recently (108) developed an essentially different conception of what the degeneration of gases is according to this the translatory motion of the molecules of gas is converted more and more at low temperatures, under the influence of the absolute zero radiation (Nullpunkts-strah-lung) of the ether, into a circular movement, such that at the zero itself the molecules of gas revolve with constant velocity about equilibrium positions, uniformly distributed in space. [Pg.201]

S (q, to) is connected to the polarizability x(q, ro) in the way shown in Equation (3). Let us turn to the most simple model case, the jellium model, in which the electrons are assumed to be free particles, moving embedded in a positive uniform charge background, obeying only Pauli s principle but not showing any electron-electron interactions. For this case of a non-interacting electron gas, the dielectric response function is given by... [Pg.180]

The absorption coefficient has been assumed independent of position (uniform catalyst concentration) and time (stable catalyst). The reactor volume average of the LVRPA for the ID model in the Cartesian coordinate x is... [Pg.155]

Figure 10 The electron density presented as for jelliutn as a function of distance, Z, from the jellium edge solid curve, charge density for the positive, uniform charge background dashed curve, charge density of the electrons. Figure 10 The electron density presented as for jelliutn as a function of distance, Z, from the jellium edge solid curve, charge density for the positive, uniform charge background dashed curve, charge density of the electrons.
Measure the thickness of the test specimen at at least five positions uniformly distributed over its surface. Calculate the mean thickness. [Pg.627]

To carry out this crude estimation one could use random numbers to choose for the particles of the system random positions uniformly distributed in the volume V of the system. That is easy. For each system configuration so generated one would calculate the energy I/(q ) [for the example (2)] and the probability density p(q ). The average of the product t/(q )p(q ) over many such configurations is evidently an unbiased estimate of / according to (2). [Pg.139]

The reason for this terminology is that in the simplest possible treatment of metallic electrons, they can be considered as free particles in the positive uniform background of the ions (the jellium model), in which case is indeed the kinetic energy in the following we adopt this terminology to conform to literature conventions. [Pg.299]

OH groups are in the para or 1,4 position to each other. This use of the prefix is confined to disubstituted benzene derivatives in such cases as para-hydrogen and paraldehyde the prefix has no uniform structural significance and is always written in full. [Pg.296]

Localized AE sources appear during load variations, startups or shutdowns, but their positions are uniformly spread over the length of the two bodies of the header this can be seen from the histogram of the localized AE events for the front body (fig.S) and for the rear body (fig.9). [Pg.78]

During electrical load variations the background noise is low and constant along the SH headers, it increases with load variations. AE sources appear during load variations, but their position are again uniformly scattered over the length of the headers. [Pg.79]

It is helpful to distinguish three different types of problem to which Newton s laws of motion may be applied. In the simplest case, no force acts on each particle between collisions. From one collision to the next, the position of the particle thus changes by v,5f, where v, is the (constant) velocity and 6t is the time between collisions. In the second situation, the particle experiences a constant force between collisions. An example of this type of motion would be that of a charged particle moving in tr uniform electric field. In the third case, the force on the particle depends on its position relative to the other particles. Here the motion is often very difficult, if not impossible, to describe analytically, due to the coupled nature of the particles motions. [Pg.367]

In the Couette flow inside a cone-and-plate viscometer the circumferential velocity at any given radial position is approximately a linear function of the vertical coordinate. Therefore the shear rate corresponding to this component is almost constant. The heat generation term in Equation (5.25) is hence nearly constant. Furthermore, in uniform Couette regime the convection term is also zero and all of the heat transfer is due to conduction. For very large conductivity coefficients the heat conduction will be very fast and the temperature profile will... [Pg.163]

Finally, values of sx are directly proportional to transmittance for indeterminate errors due to fluctuations in source intensity and for uncertainty in positioning the sample cell within the spectrometer. The latter is of particular importance since the optical properties of any sample cell are not uniform. As a result, repositioning the sample cell may lead to a change in the intensity of transmitted radiation. As shown by curve C in Figure 10.35, the effect of this source of indeterminate error is only important at low absorbances. This source of indeterminate errors is usually the limiting factor for high-quality UV/Vis spectrophotometers when the absorbance is relatively small. [Pg.411]


See other pages where Uniformly positive is mentioned: [Pg.523]    [Pg.191]    [Pg.245]    [Pg.418]    [Pg.357]    [Pg.418]    [Pg.63]    [Pg.743]    [Pg.327]    [Pg.37]    [Pg.58]    [Pg.59]    [Pg.151]    [Pg.523]    [Pg.191]    [Pg.245]    [Pg.418]    [Pg.357]    [Pg.418]    [Pg.63]    [Pg.743]    [Pg.327]    [Pg.37]    [Pg.58]    [Pg.59]    [Pg.151]    [Pg.201]    [Pg.446]    [Pg.169]    [Pg.108]    [Pg.387]    [Pg.176]    [Pg.64]    [Pg.609]    [Pg.623]    [Pg.27]    [Pg.104]    [Pg.419]    [Pg.434]    [Pg.504]    [Pg.502]    [Pg.112]    [Pg.130]    [Pg.31]    [Pg.70]    [Pg.19]   
See also in sourсe #XX -- [ Pg.124 ]




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