Frenkel relationships

A low value for Kp means a big precursor effect since k 4 is low, that is the probability of desorption is low and the lifetime in the precursor state is high allowing a wide area of diffusion on the surface and thus a high probability for adsorption into the final chemisorbed state. Approximate diffusion circles are shown in fig. 13 based on the following simple Frenkel relationships,... 

The surface residence time, tsurf, is related to the heat of adsorption, AH, and temperature, T, through a Frenkel-type relationship ... 

Van Duuren, B.L., Katz, C., Goldschmidt, M., Frenkel, K., and Sirak, A. Carcinogenicity of haloethers. II. Stmcture-activity relationships of analogs of bis(chloromethyl) ether, J. Nat. Cancer Inst, 48 1431-1439, 1972. 

A relationship between human lymphocyte antigens and nickel sensitivity exists and predicts that individuals with this antigen have a relative risk of approximately 1 in 11 of developing nickel sensitivity (Mozzanica et al. 1990). Antibodies to hydroxymethyl uracil, an oxdized DNA base, have also been shown to be increased in some nickel-exposed workers (Frenkel et al. 1994). A preliminary study using imaging cytometry of nasal smears obtained from nickel workers indicates that this method... 

Some very interesting ideas concerning the relationship between free-volume formation and the energy of one mole of hole formation were developed in detail by Kanig42. Kanig introduced some improvements to the definition of free-volume, On the basis of Frenkel s ideas43 he divided the free-volume into two parts, one of which is determined only by the thermal vibrations of atoms in the lattice of a real crystal while the other is connected with inherent free-volume, i.e. voids and holes. It is the latter that makes possible the exchange of particles, i.e. the very existence of the liquid state. He introduced some new definitions of fractions of free-volume ... 

The experimental kinetics of accumulation of the Frenkel defects - F centres in alkali-halide crystals at liquid-helium temperatures - was studied in [17] and [40] within the framework of a model that yields a logarithmic dependence of the concentration of defects on the irradiation dose - equation (6) of Table 7.6). Although we criticized this relationship above, at low radiation doses it can be represented as a polynomial in powers of uqVq resembling equations (3) to (5). At the same time cogent arguments exist favoring the... 

Maalekuu, K., Elkind, Y., Leikin-Frenkel, A., Lurie, S., and Fallik, E. (2006). The relationship between water loss, lipid content, membrane integrity and LOX activity in ripe pepper fruit after storage. Postharvest Biol. Technol. 42, 248-255. 

The empirical relationship [Eq. (15)] obtained by fitting the experimental electric field dependence to the measured data suggests a Poole-Frenkel (PF) type mechanism17. The PF effect deals with a carrier trapped in a coulombic barrier19. The applied field causes a reduction of 0pFE 2in the barrier height and therefore the probability of escape is increased in the presence of the applied field. The slope... 

Cohen and Turnbull [87] generalized somewhat the theoretical concepts of the relationship between diffusion and self-diffusion of liquids modelled by assemblies of rigid spheres and obtained on the basis of the theories of Frenkel and Eyring, Fox and Flory [88] and Williams, Landell and Ferry [89] the equation ... 

Figure 7 shows the field dependencies of the mobility for different values of G/kT, assuming = 0. The S-shaped < < >> versus field relationship of Fig. 6 is recovered. The mobility saturates with decreasing field at low fields and increases in a Poole-Frenkel fashion at high fields. As (GlkT) —> 0, the mobility decreases with field at high fields. This is due to the saturation of the drift... 

Santos-Lemus and Hirsch (1986) measured hole mobilities of NIPC doped PC. Over a range of concentrations, fields, and temperatures, the transport was nondispersive. The field and temperature dependencies followed logn / El/2 and -(T0IT)2 relationships. For concentrations of less than 40%, a power-law concentration dependence was reported. The concentration dependence was described by a wavefunction decay constant of 1.6 A. To explain a mobility that shows features expected for trap-free transport with a field dependence predicted from the Poole-Frenkel effect, the authors proposed a model based on field-enhanced polaron tunneling. The model is based on an earlier argument of Mott (1971). 

Wei, H. and Frenkel, K., Relationship of oxidative events and DNA oxidation in Senear mice to in vivo promoting activity of phorbol ester-type tumor promoters, Carcinogenesis, 14, 1195, 1993. 

Figure 1 shows that the viscosity-temperature relationship revealed by plotting In 77 against VT is linear for the base (1) and compositions 1 (2) and 2 (3) with additive content up to 20 wt% for other analyzed fluids (4), (5), and (6) this relationship is not linear. Therefore, we may conclude that the flow of some analyzed fluids does not obey the activation mechanism described by the Arrhenius-Frenkel-Eiring equation within the studied temperature range. 

The relationships between the viscosity of melts (liqu ds), the diffusion phenomena and the rate of crystal growth have been the subject of numerous theoretical and experimenal Siudies (cf. Frenkel, 1945 Doremus, 1973). A useful practical parameter is provided by the product uij) which forsimple oxides(Si02, GeO, P205>is proportional to undercooling AT= Tjiq — T. It therefore holds that... 

This relationship for Frenkel excitons was derived in (14) it can be seen from its derivation that it is independent of the model and, therefore, is valid also for ground state large-radius excitons as well as for electrons and holes in semiconductors. 

Van Duuren, B. L., C. Katz, B. M. Goldschmidt, K. Frenkel, and A. Sivak. 1972. Carcinogenicity of halo-ethers. II. Structure-activity relationships of analogs of bis(chloromethyl) ether. /. Natl. Cancer Inst. 48(5) 1431-1439. 

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