No description available.

京都大学 / 新制・課程博士 / 博士(人間・環境学) / 甲第23286号 / 人博第1001号 / 新制||人||236(附属図書館) / 2020||人博||1001(吉田南総合図書館) / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 内本 喜晴, 教授 田部 勢津久, 教授 高木 紀明 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20391号 / 工博第4328号 / 新制||工||1671(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 中村 正治, 教授 辻 康之, 教授 小澤 文幸 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第21433号 / 人博第871号 / 2018||人博||871(吉田南総合図書館) / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 内本 喜晴, 教授 吉田 寿雄, 准教授 戸﨑 充男 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM

学位プログラム名: 京都大学大学院思修館 / 京都大学 / 新制・課程博士 / 博士(総合学術) / 甲第23346号 / 総総博第19号 / 新制||総総||3(附属図書館) / 京都大学大学院総合生存学館総合生存学専攻 / (主査)教授 寶 馨, 教授 内本 喜晴, 特定教授 橋本 道雄 / 学位規則第4条第1項該当 / Doctor of Philosophy / Kyoto University / DFAM

No description available.

This thesis describes the preparation and characterization of manganese oxide catalysts and their application in the oxidation of acetone, a typical volatile organic compound (VOC), and ozone decomposition. This topic is of great value because of environmental concerns of the elimination of the harmful VOCs and ozone. Manganese oxide was chosen because it is a well-known complete oxidation catalyst for VOCs and also an active catalyst for ozone decomposition. Two cases of studies were carried out in this work. The first study involved the oxidation of acetone using ozone on silica- and alumina-supported manganese oxide catalysts deposited on aluminum oxide foam substrates. The characteristics of the catalysts were determined through various techniques, including x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), Brunauer-Emmett-Teller (BET) surface area analysis, temperature-programmed reduction (TPR), and oxygen chemisorption. The use of these techniques allowed better understanding of the nature of the catalysts. Activity tests were carried out in the acetone oxidation reaction and it was found that the usage of ozone substantially reduced the oxidation temperature. Steady-state in situ Raman spectroscopy was also carried out to better understand the mechanism of the acetone oxidation reaction using ozone. The second study involved an investigation of structural and electronic properties of manganese centers of the MnOx/SiO2 and MnOx/Al2O3 catalysts during the ozone decomposition reaction using in situ x-ray absorption spectroscopy (XAS). The number of surface active sites was again determined through TPR and oxygen chemisorption measurements. The performance of the catalysts with different loadings and supports were also compared. / Master of Science

京都大学 / 新制・課程博士 / 博士(人間・環境学) / 甲第23996号 / 人博第1048号 / 新制||人||246(附属図書館) / 2021||人博||1048(吉田南総合図書館) / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 内本 喜晴, 教授 高木 紀明, 教授 白井 理, 教授 光島 重徳 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM

Given the wide range of properties and applications of intermetallic compounds, it is important to achieve a detailed understanding of their structure and bonding. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge spectroscopy (XANES) were used to study the electronic structure of several types of pnictides (compounds containing Pn = P, As). ZrAs2, forming a PbCl2-type structure, has been established to be a genuine binary phase that is strictly stoichiometric. At 900 °C, it supports extensive solubility of Ge to form the ternary extension Zr(GexAs1−x)As (0 ≤ x ≤ 0.4). XPS analysis and band structure calculations confirmed that the Ge and As atoms are anionic in character and that the substitution of Ge for As is driven by a depopulation of anion–anion antibonding states. ZrCuSiPn and REMAsO are important representatives of ZrCuSiAs-type materials. The small magnitudes of the binding energy shifts in the XPS spectra of ZrCuSiPn suggest significant covalent character in the Zr–Si, Zr–Pn, and Cu–Pn bonds, consistent with a three-dimensional structure. On progressing from ZrCuSiP to ZrCuSiAs, the charge transfer from metal to Pn atoms becomes less pronounced, as indicated by changes in the intensity of the Cu K-edge and Zr K, L-edge XANES spectra. Binding energy shifts and satellite features of the XPS spectra of REMAsO indicated that bonding in the [REO] layer is ionic, whereas bonding in the [MAs] layer is strongly covalent. Altering the electronic structure of one layer (by M or RE substitution) does not affect the electronic structure of the other layer, consistent with a two-dimensional structure in REMAsO. Metal-rich phosphides M2P (forming Cr2P-, Fe2P-, and Co2P-type structures) and M3P (forming Ni3P-type structures) were examined by XPS and XANES. The P 2p3/2 binding and P K-edge absorption energies decrease with greater ionic character of the M−P bonding and indicate the presence of anionic phosphorus. Interatomic effects play a more important role in affecting the energy shifts in these metal-rich phosphides than in the monophosphides, becoming more pronounced with higher metal concentration. Surprisingly, intraatomic effects dominate in mixed-metal phosphides (Ni1-xMx)2P despite evidence of metal-to-metal charge transfer from the Ni XANES spectra and Ni 2p XPS satellite features.

There is a great need in the transportation industry for high strength, high stiffness and lightweight materials with excellent dimensional stability. The use of these materials reduces fuel consumption and greenhouse gas emission as well as malfunctioning of components when subjected to fluctuating temperatures. Metal matrix composites (MMCs) are designed to meet these needs of transportation and other industries. However, their use is limited by lack of information on their thermal behaviour. In addition, reactions that occur in MMCs alter their microstructure and properties. These reactions have been widely investigated using X-ray Diffractometry (XRD) and electron microscopy (EM). However, these techniques cannot provide information such as charge transfer and local elemental structures in materials. Synchrotron X-ray Absorption Spectroscopy (XAS) could be used to identify reaction products in MMCs as well as provide information which XRD and EM cannot provide.<p> The thermal behaviour of Al-Mg alloy A535 containing fly ash particles as well as charge transfer and reactivity in particulate aluminium alloy metal matrix composites (MMCs) were investigated in this work. The materials studied were (i) Al-Cu-Mg alloy AA2618 and its composites reinforced with 10 and 15 vol.% alumina (Al2O3) particles and (ii) Al-Mg alloy A535 and its composites reinforced with a mixture of 5 wt.% fly ash and 5 wt.% silicon carbide, 10 wt.% and 15 wt.% fly ash. The investigative techniques used included Differential Scanning Calorimetry (DSC), Thermomechanical Analysis (TMA), Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and synchrotron X-ray Absorption Spectroscopy (XAS).<p> The results obtained showed that the coefficient of thermal expansion (CTE) of A535 decreased with the addition of fly ash and silicon carbide. Also, the addition of these particles improved the dimensional stability of the alloy in that the residual strain, åp, cycling strain, åc, and CTE decreased. The results obtained from XAS measurements showed evidence of charge redistribution in the aluminium in AA2618 with the addition of alumina particles. The results obtained from XAS measurements showed evidence of charge redistribution in the aluminium in AA2618 with the addition of alumina particles. The addition of alumina particles into AA2618 increased the p-orbital population and also changed the surface chemistry of the matrix. It was also demonstrated that the XAS technique can be used to determine the presence of various oxides in industrial fly ash and spinel (MgAl2O4) in alumina and fly ash particles extracted from the MMCs.