Penetration function definition

Treatment of class (c) membranes, on the other hand, presents a considerably more complicated problem. Here, S and DT in Eqs. (1) and (2) are functions of the spatial coordinates. The problem becomes much more acute if S and DT are also dependent on C 4,5). Under these conditions, transformation of Eqs. (2) into (3) is not generally possible and there are no standard methods, as in the previous cases, of fully characterizing the membrane-penetrant system 3 "5). There is usually no difficulty in determining an overall or effective solubility coefficient but the definition of useful effective diffusion coefficients is a more difficult matter, which, not surprisingly, is a major concern of current research in the field. 

Figure 2. Penetration depth of light as a function of wavelength in tissue. The curves indicate approximate upper and lower bounds for the penetration depth for typical soft tissues. For example, liver is highly absorbing and has a penetration depth spectrum similar to the lower curve, whereas tissues such as brain or muscle have much lower pigmentation and so have larger penetration depths typically like the top curve. The insert shows the approximately exponential decrease in light fluence or fluence rate with depth in tissue and the definition of the effective penetration depth, 5.

The valence orbitals are not, in fact, external to the cores each function vanishes only at infinity. There is definite penetration of the core region by the valence electrons. 

Figure 19.2 Definition of the depth of concrete removal for structures subjected to chloride-induced corrosion as a function of the present condition of the structure (time t ) and the estimated evolution of the chloride penetration damage at the time if when use of the structure is expected to finish (or new repair is planned).

The above definitions are particularly suitable for investigations in computer simulations. They can be applied also to a fictitious layer in the bulk liquid, except that in the latter case decay can happen by molecules crossing across the region -that is, by penetrating the sphere not allowed in the case of protein. In the case of the protein hydration layer, these survival correlation functions decay slowly for the hydration layer. 

Calculate the mass flux of a penetrant diffusing through a polymer membrane as a function of the penetrant mass fraction. Start with the definition of the mass flux with respect to the mass average velocity. 

We will compare the relative total intensity with the depth of real geometrical structures. Figure 9.49 shows the observed depth as function of the raster geometry of the mask. The observed depth of a geometrical structure increases progressively with increased width of perforations, if the period i is constant. The structural depth decreases noticeably at small widths of perforation. However, the observed depth does not remain constant if the period i varies at a constant transmission ratio (i.e. o/i = const.). The area dependent definition of the ratio of transmission does not allow it. If only the transmission controls the UV-penetration depth, it would be expected that the observed structural depth is constant for a constant ratio of transmission which corresponds to a constant relative total intensity. 

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