Papers by Author: Yusuke Moriyoshi

Abstract: Fe- and Eu-doped TiO2 nanocrystals were synthesized via Ar/O2 thermal plasma oxidation of liquid precursor mists. The use of mists ensures atomic level mixing of the elements and high supersaturation of the evaporated species upon plasma oxidation, which favors nanocrystal formation upon condensation. Iron-doped TiO2 nanopowders with controlled iron to titanium atomic ratios (RFe/Ti) ranging from 0 to 20%, were synthesized by oxidative pyrolysis of liquid-feed metallorganic precursors containing titanium tetra-n-butoxide (TTBO) and ferrocene. Europium doped TiO2 luminescent nanocrystals were also synthesized via RF thermal plasma oxidation of liquid precursor mists containing TTBO and europium nitrate.

Abstract: We investigated the electrical polarizability of MgO and B2O3 containing bioactive glass (MBG). The MBG material with good manufacturing properties but low bioactivity was electrically polarized at a high dc field. The electrical polarizability of MBG was evaluated by thermally stimulated depolarization current (TSDC) measurements and immersion in simulated body fluid (SBF). The early precipitation of calcium phosphate on the negatively charged surface of the treated MBG demonstrated the increased bioactivity of the material and confirmed its polarizability. It is suggested that the electrical interactions between the polarized MBG and ions in SBF promoted the formation of the calcium phosphate precipitation. Accordingly, the increased bioactivity of the MBG in SBF is suggested to demonstrate the conversion of MBG into electrovector ceramics by the polarization treatment.