Thickness of diffusion layer

The thickness of these layers is in the range of <2h = 0.4 to 0.6 nm for the compact layer, space charge layer, and c(d = 1 to 10 nm for the diffuse layer. The thickness of space charge layer, dac, and the thicknesses of diffuse layer, (fd, depend on the concentrations of mobile charge carries Tii in the semiconductor and in the aqueous solution, respectively. The Debye length, Ljy, may be used as a measure of the thickness of these two respective layers as shown in Eqn. 5-61 ... 

Snrface coverage Dnration of a potential cycle, s Laplace transform Dimensionless cnrrent Dimensionless cathodic peak cnrrent Dimensionless anodic peak cnrrent Dimensionless net peak cnrrent Thickness of diffusion layer... 

Figure 10.13. Variations in the effective thickness of diffusion layer 8 over an electrode with a microprofile.

In Eq. (13) km is the local mass transport coefficient D/S, that is, diffusion coefficient divided by the thickness of diffusion layer. High mass transport rates can be achieved by electrode movement,... 

X 10 to 1.4 X 10 cm s , see in all cases the calculated value is always greater by 10-20 times than the experimental one. This is perhaps due to the electrode passivation that cuts off part of the electrode surface from the process. The effect of passivation on the electrode reactions of solvated electrons is discussed in detail in Section 7. Here we shall only mention that passivation does not alter the limiting diffusion current. The different effect of passivation on diffusion and kinetic currents is related to the fact that at the employed rotation rates the thickness of diffusion layer (that determines ij) far exceeds that of the reaction layer (that determines iJ... 

The specific dissolution rate constant (iCi) is a constant for a specific set of conditions, although it is dependent on temperature, viscosity, agitation or stirring (which alters the thickness of diffusion layer) and volume of the solvent. 

The changes of electrolyte concentration cause the changes of surface charge and consequently the thickness of diffusion layer. The reduction of this layer favours the coagulation (Fig. 5.17). 

Fig. 1.3.1 Variation of the concentration (c) of a species as a function of the disttince from the electrode surface (x) in the case of a steady-state electrode reaction. 1 True concentration profiie 2 fictitious profile of Nernst. Thickness of diffusion layer (5) depends on the rate of stirring, while c(x = 0) depends on the overpotential...

D = diffusion coefficient of drug in diffusion layer h = thickness of diffusion layer A = surface area of drug particles... 

When a steady-state of non-zero flux is to be reached, then non-planar diffusion and/or controlled convection of the electrolyte along the electrode surface are required. The term (TcDt) -, called the thickness of diffusion layer, can then be substituted by a constant value 3, Nemst thickness). The flux J is related to the faradic current I by the equation ... 

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