The author's aim is to investigate ZnO varistors with high voltage to 1000V/mm and good resistance to electrical degradation, which could be applied to the UHV transmission systems and reduce ZnO varistor element amounts in surge arresters. The conduction processes in ZnO varistors is clarified. By adjusting additive type and amounts in ZnO the electrical properties of ZnO varistors can be controlled. Based on this recipe, Y, Cr, Ni, B, Si oxides were added in this study. These oxides can be divided into two categories, the Y doping group and the Si doping group. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

濃度3Mの硝酸亜鉛水溶液中170°Cで7 h水熱処理し，ついで大気中600℃で再酸化処理して合成した酸化亜鉛ZnOは持続的な暗所抗菌性を示す．このZnOについて物理化学な物性を詳細に検討した．また，カリウムKとりんPを1:3の原子比率で添加固溶させたアナターゼ型酸化チタンTiO2は暗所でも抗菌性を示すことを新たに見出した．その抗菌性発現のメカニズムについて検討した結果を報告する． / Both ZnO and TiO2 have high potential as antibacterial agents which are able to apply in various fields. Although there are already many studies about these materials focusing on their antibacterial activity, they are still getting more attention from researchers due to their unclear mechanism under dark. There have been very few reports mentioning clearly about this. Besides, the effects of the preparation methods and their physicochemical properties to the antibacterial property of ZnO, TiO2 and doped TiO2 under dark also have not been well-characterized. In the present study, synthesis and physicochemical evaluation of metal oxides which reveal antibacterial activity even in the dark conditions have been performed. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第20726号 / エネ博第354号 / 新制||エネ||70(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻 / (主査)教授 佐川 尚, 教授 萩原 理加, 教授 野平 俊之 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DGAM