Hydrogen atoms and hydroxyl radicals produced in the glow-discharge electrolysis of aqueous solutions have been identified by e.s.r. spectroscopy using 5,5-dimethylpyrroline-l-oxide (DMPO) as a spin trap. Tlie trap is able to penetrate the primary reaction zone (at the discharge/solution interface) to scavenge for free radicals. No evidence for the presence of hydrated electrons (ea; ) was found.
Very precise electrical conductivity data on a series of six glasses of molar composition 25(xNa2O + (1-x)K2O) - 5Al2O3 - 70SiO2 with 0.95 ≤ x ≤ 1 have been obtained over a large temperature range (∼ 310°C). Analysis of this data suggests that the pre-exponential term in the Arrhenius conductivity equation is temperature independent
Very precise electrical conductivity data on a series of six glasses (molar composition 25[xNa20 + ( I -x)K20]-5AI2O3-70SiO2 with 0.95 5 x 5 1 ) have been obtained over a large temperature range (=31O"C). Analysis of these data suggests that the preexponential term in the Arrhenius conductivity equation is temperature independent.
The enthalpy changes during structural relaxation or physical aging of a 58ZrF4-33BaF~-5LaF3-4AlF3 (ZBLA) glass during annealing well below the glass-transition temperature have been studied using differential-scanning calorimetry at several sub-T, temperatures. Substantial relaxation within the course of several hours was detected at temperatures as low as sixty degrees below Tg (58510. The relaxation process is extremely nonlinear and self-retarding. The time dependence of the enthalpy during the initial stages of annealing was modeled approximately using the Narayanaswamy-Tool approach. The structural-relaxation parameters obtained from this fit were used to predict rates of physical aging for rapidly cooled ZBLA glass at temperatures close to ambient.
Beginning with a 19BaF2−27ZnF2−27YbF3−27ThF4 (mol%) base glass, compositional modifications were made to improve optical properties and glass‐forming ability. Replacement of YbF3 by LuF3 removed a strong near‐ir electronic absorption band, and small additions of LiF and NaF improved glass quality. The multicomponent BaF2/ThF4 glasses had higher refractive indices and lower expansion coefficients than fluorozirconate and fluorohafnate glasses. In the 6 to 10 μm region, these materials exhibit absorption coefficients an order of magnitude lower than those reported for other heavy‐metal fluoride glasses.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.