The time-dependent diffusion coeff. is independent of the microscopic details of the restricting geometry and depends only on the surface-to-vol. ratio S/V of the pore space. Pulsed field gradient NMR is an ideal tool for measuring the time-dependent diffusion coeff. The min. observation time is detd. by the min. length of gradient pulses and the subsequent recovery of the app. from eddy-current and magnetoacoustic effects. In the current expts., the min. observation time is about 7 ms. The max. time is detd. by the spin-lattice and spin-spin relaxation times of the fluid. For these expts., the max. observation time was chosen to be T1 of the spins. Pulsed field gradient NMR expts. were conducted on fluid-satd. glass sphere packs and on a sample of onion tissue. The diffusion coeff. for the intracellular fluid in an onion was detd. The diffusion coeffs. for distd. water and viscous oil in the pores of a monosized sphere pack were also detd.
Mendeley saves you time finding and organizing research
Choose a citation style from the tabs below