Based on our experimental results, the growth of carbon nanotube arrays in our experimental condition could not be diffusion-limited.
Therefore there should not be any diffusion of holes away from the metal particles in any case and Ag cannot inject holes into Si.
Indeed, CT has a net positive charge and an estimated log partition coefficient of -2.7 [ 13], which would not be consistent with diffusion of CT through plasma membranes.
Although it is desired to measure only the profiles caused by tracer diffusion, chemical diffusion could not be avoided under the given experimental conditions.
Therefore, the relative Fe enrichment in the center may not be driven by thermal diffusion but could be caused by the effect of temperature on the partitioning.
However, it is acknowledged that mixing will not be rapid, as the diffusion coefficient through the gel vitreous will be considerably less than that through the sol vitreous.
The extent of apoptosis in the hippocampus could not be related to quantitative diffusion data obtained with MRI.
Due to the high concentration in the supernatant the internal fluorescein concentration could not be quantitated during in-diffusion.
However, important process parameters including ion exchange at the surface, diffusion in porous media and mass transfer either by convection or diffusion should not be neglected [14].
Oxygen diffusion would not be important for healthy concrete.
The "energy of activation" of diffusion may not be a useful concept for such systems.
