Quenching of pyrene fluorescence by oxygen was used to determine oxygen diffusion coefficients in phospholipid dispersions and erythrocyte plasma membranes. The fluorescence intensity and lifetime of pyrene in both artificial and natural membranes decreases about 80% in the presence of 1 atm O2, while the fluorescence excitation and emission spectra and the absorption spectrum are unaltered. As...

Pure uo2 sinters readily at temperatures below 1600°c when non-stoichiometric oxygen introduced during the presintering treatment is available for diffusion and subsequent densification. In the absence of excess oxygen sintering occurs at temperatures above 1600°C by self-diffusion of stoichiometric oxygen in uo2 • Grain growth occurs when open porosity has been eliminated and is controlled by ...

....................................................................................................................3 Background ...............................................................................................................4 Mathematical Model .........................................................................6 Analytical Solution ............................................