The Open-Access Journal for the Basic Principles of Diffusion Theory, Experiment and Application Hexane Self-Diffusion in Bed of Glass Spheres. Testing Applicability Range of the Pore-Hopping Model

نویسندگان

  • Mikuláš Peksa
  • Jan Lang
  • Milan Kočiřík
چکیده

1. Introduction PFG NMR experiment is in principle capable to provide important transport-structural parameters of system consisting of a liquid confined in a porous matrix such as surface-to-volume ratio and tortuosity. The apparent diffusion coefficient is easily obtained in the case of Gaussian shape of the diffusion propagator. Dependence of these values on the diffusion time in a short time limit is then used to derive the surface-to-volume ratio by means of the formula derived by Mitra [1]. Tortuosity is, on the other hand, derived from the long time limit of the apparent self-diffusion coefficient. The general description of the apparent diffusion coefficient dependence for all values of diffusion time has been facilitated by Padé approximant [2]. It has been shown previously several times that the assumption of Gaussian diffusion propagator may not be true for intermediate diffusion times. This effect is also called diffusion diffraction. Callaghan [3] reported interpretation of diffusion diffractions in beds of spheres by means of pore-hopping model.

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تاریخ انتشار 2011