Xenon diffusion

Close-packed monolayer model, M0O3, 37 7 Cloverite, xenon diffusion in, 42 14 Cluster formation, 32 343-344 Cluster modeling... 

Fig. 2 shows the spectrum as a function of time of HP xenon diffusing into porous Vycor glass, which has interconnecting pores of 42A diameter. The experiment in this case was done in batch mode, where a previously collected volume of HP xenon is passed into the sample space in a static NMR probe containing the Vycor sample. The spectrum was collected with a series of pulses with small tip angles so as not to destroy the magnetization of the HP xenon. The experiment is started even before there is gas in the sample space so that... 

Sref = 0 is the reference (xenon gas at zero pressure) 5s is characteristic of xenon -wall interactions, and depends on the form and the dimensions of the internal void volume, and on the ease of xenon diffusion 5xe corresponds to Xe-Xe interactions, this term being proportional to N and inversely proportional to the void volume. Under these conditions, 5 varies linearly with N and the larger the slope, the smaller the internal void space. It has been observed that for a given temperature of treatment, the residual water concentration increases with the concentration of the transition metal cations (5). 

In this work we have applied the I29xe-NMR spectroscopic technique using octamethylcyclotetrasiloxane (OMCTS) as a blocking agent to avoid the interparticle xenon diffusion over different zeolite catalyst samples. We were able to extract new information about the microporosity in individual crystallite particles. 

Xenon diffuses throu a pin-hole at race will hydrogen effuse through d lure and pressure ... 

HP xenon diffusion measurements can also be used to determine S/V ratios in porous materials, including soft materials. Extending the previous work done in liquids by Stejskal and Tanner,Butler et al determine 5/F ratio from the rate of xenon polarization exchange between the gas phase and xenon dissolved in the solid phase. This method was applied to porous polymer samples, but applications to the characterization of lung spaces are envisioned. 

An estimate of the average xenon diffusion constant in PMP can be made from the coalescence of peaks if independent domain size information(S,77j is available. A domain size for the amorphous region can be determined by fitting the proton magnetization recovery curve shown in Figure 11. The equation describing the recovery of the magnetization(26j is... 

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