Diffusion behaviour

This diffusive behaviour is not just limited to ink in water - it occurs in all liquids, and more remarkably, in all solids as well. As an example, in the alloy brass - a mixture... 

Theoretically, the CV can be strictly derived from the diffusion behaviour of the reactant and product. 

The reduction of aryl-substituted vinyl halides by electrochemically generated aromatic anion radicals has also been investigated in DMF (Gatti et al., 1987). Counter-diffusion behaviour at low driving forces (pp. 34, 35) does not appear as clearly as in the case of aryl halides (Fig. 11). However, analysis of the log k vs E° plot according to a quadratic activation-driving force relationship gave standard potential and intrinsic barrier values that... 

Scheme 37 Structures of GPI analogues that were synthesized by the Bertozzi group in order to study the diffusion behaviour in living cells.

Quite clearly there remains a great deal of basic NMR and modelling work to be done before we can claim to understand the relaxation and diffusion behaviour of horticultural products. In particular there is a need for more... 

The sorption and diffusion behaviour of gas mixtures is of particular interest from the point of view of membrane gas separation, which is steadily gaining in importance by virtue of its low energy requirements. On the basis of the dual mode sorption model, one may reasonably expect that sorption of a binary gas mixture A, B in the polymer matrix will exhibit little gas-gas interaction and hence will tend to occur essentially additively. In the Langmuir-like mode of sorption, on the other hand, there will be competition between A and B for the limited number of available sites. These considerations led 67) to the following reformulation of Eqs. (8) and (9)... 

In Eq. (34), fA, fB express in quantitative terms the concept (already referred to above) of the degree of continuity of the respective component phases. Model calculations based on Eq. (34) with various values of fA, fB were used to determine the kind of two-phase structure that could reasonably be expected to give rise to the ionic diffusion behaviour observed in cellulose membranes106) (cf. following section). 

The discussion given in this section shows that non-homogeneity of membrane electrical properties is widespread and markedly influences ionic sorption and diffusion behaviour. Proper understanding of these effects is, therefore, important and may be expected to contribute materially to the design of more highly permselective membranes. 

The inconsistency in this approach and all other mode coupling theoretical approaches [9, 37, 57, 176] is that a finite diffusion coefficient has been assumed to define the diffusive behaviour of the self-dynamic structure factor, and then it has been concluded that this diffusion coefficient itself diverges. 

The diffusion behaviour of Shirakawa polyacetylene is complicated by its fibrillar morphology and high surface area, so that weight changes depend on pore transport and surface adsorption, as well as on diffusion into the fibrils. Chien 6) has reviewed earlier studies of the diffusion of dopant counter-ions in Shirakawa polymer and has emphasised the wide range of values of diffusion coefficient which are reported and which depend a great deal upon the morphological model chosen to interpret experimental data. 

Bernkop-Schniirch, A., and R. Fragner. 1996. Investigations into the diffusion behaviour of polypeptides in native intestinal mucus with regard to their peroral administration. Pharm Sci 2 361. 

Ewen B, Maschke U, Richter D, Farago B (1994) Neutron spin echo studies on the segmental diffusion behaviour in the different chain sections of high molecular weight poly(dimetylsiloxane) melt. Acta Polym 45 143-147 Faitelson LA (1995) Some aspects of polymer melts rheology. Mech Compos Mater 31(1) 101—116... 

Diffusion behaviour of silicon atoms in the growing Pd2Si layer was shown by C.M. Comrie and J.M. Egan165 166 to be different from that in the... 

The diffusion behaviour of organic vapours is much more complicated than that of simple gases. Normally the interaction is much stronger, so that the diffusion coefficient becomes dependent on the concentration of the penetrant ... 

In order to elucidate the PS diffusion behaviour in PMMA gel, the PFGStE aH NMR measurements have been made with varying values of the diffusion time A. For samples A1 and A2, the diffusion coefficients for the fast and slow diffusion components (as indicated by Dfast and Dsiow, respectively) and the corresponding fractions (/fast and/siow, respectively) are determined by using Equation (2), and Dfast and Dsiow are plotted in Figure 14A and B. The single diffusion coefficients of... 

Let us note the diffusion behaviour of small molecules, that is unreacted MMA, in the PMMA gel matrix. Using the vinyl peak of the unreacted MMA, PGSE 3H NMR measurements on the small molecule diffusion are performed for PMMA gel samples A1-A4 with varying A. The experimental data lie on a straight line in the A range from 60 to 500 ms, and the slope of the plots is independent of the diffusion time A. This clearly shows that the diffusion of the small molecule is a single mode and not restricted. The diffusion coefficient of MMA (D) as obtained from the slope of the straight line is also independent of the polymer concentration for samples A1-A4, D (10 9 m2 s ) 1.4,1.5,1.5 and 1.4, respectively. The... 

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