The radical sites generated by the visible light irradiation of nitrogen-doped TiO 2 particles prepared by a mechanochemical method have been studied using cw-EPR spectroscopy. The powders prepared by planetary milling of the anatase TiO 2 with urea clearly show an absorption in the visible region, indicating doping of nitrogen. Visible light irradiation with wavelengths longer than 420 nm induces a nitrogen-centred radical site. The radical site is assigned to the interstitial NO 2À 2 radical. In the presence of air, a reversible response of the growth and decay of paramagnetic sites was observed during and after photolysis. In contrast, in degassed samples, the decay of the NO 2À 2 signals is accompanied by the concomitant growth of the neutral NO radical site after irradiation, suggesting breaking of the N-O bond.
We studied Cu-Zr-based alloys having exceptionally high glass-forming ability (GFA) and investigated the influence of Ag and Al addition on their structure and crystallization behavior. Most of the bulk glassy alloys (BGAs) do not contain any crystals, while some samples studied by high-resolution transmission electron microscopy (HRTEM) were found to contain welldeveloped medium-range order zones and nanoparticles in a bulk form. The crystallization kinetics of Cu 55 Zr 45 , Cu 50 Zr 50 , Cu 55-x Zr 45 Ag x (x = 0, 10, 20), Cu 45 Zr 45 Al 5 Ag 5 , Cu 44 Ag 15 Zr 36 Ti 5 , and Cu 36 Zr 48 Al 8 Ag 8 glassy alloys was analyzed. An influence of the cooling rate on the formation of glassy phase and thermal stability of the Cu-based glassy alloys on heating was also studied. The crystallization kinetics and phase composition of the ribbon-shape and bulk glassy samples of Cu 36 Zr 48 Al 8 Ag 8 alloys were also analyzed. The results also indicate that the best glass-forming compositions are possibly located at slightly off-eutectic area, owing to the shift of the eutectic point due to the nonequilibrium processing conditions.
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.