Subject self-diffusion constant

The purpose of this introduction, other than definition of terms, has been to summarize the key aspects of Tn in a manner slightly different than that employed in ref 1. A further purpose was to update certain topics of particular importance to understanding the structural implications of Ty, as with NMR. In some instances a full section has been prepared, as with zero shear melt viscosity, %, and self diffusion constant, Dq (Section V). New smdies of early Ueberreiter papers have also been included. In other instances, specific subject areas treated briefly in ref 1 are the topic of individual papers in this Symposium. 

The atbove-described Debye-Smoluchowski model is subject to severe limitations (Wilemski and Fixroam, 1973). First, the choice of the coordinate system is not self-evidently valid. Second, the mutual diffusion coefficient is assumed to be constant, even for short separation distances between A and B, where some vairiations are expected. Third, the diffusion ecjuation is only valid for low concentrations. A last limitation is due to the method of describing the reaction process in which it is... 

---