京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18641号 / 理博第4020号 / 新制||理||1579(附属図書館) / 31555 / 京都大学大学院理学研究科化学専攻 / (主査)教授 北川 宏, 教授 吉村 一良, 准教授 前里 光彦 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19014号 / 工博第4056号 / 新制||工||1624(附属図書館) / 31965 / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 杉野目 道紀, 教授 澤本 光男, 教授 辻 康之 / 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(理学) / 甲第20205号 / 理博第4290号 / 新制||理||1616(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 依光 英樹, 教授 大須賀 篤弘, 教授 丸岡 啓二 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(薬科学) / 甲第21051号 / 薬科博第94号 / 新制||薬科||10(附属図書館) / 京都大学大学院薬学研究科医薬創成情報科学専攻 / (主査)教授 大野 浩章, 教授 竹本 佳司, 教授 高須 清誠 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM

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No description available.

The J-M Reef of the Stillwater Complex, Montana (a large layered mafic intrusion), is one of the highest grade platinum group element (PGE) deposits known in the world, producing primarily palladium and platinum in a 3.4:1 ratio. "Ballrooms" of the Stillwater Complex are anomalously wide areas within or stratigraphically below the J-M Reef that host platinum group element mineralization. Ballrooms have two typical morphologies (type 1 and type 2); the first is an abrupt thickening of the mineralization that extends below the Reef Package and the second is a gentle widening of the Reef Package and associated reef mineralization to a width of over 6 m. Ballrooms are highly variable in size. Minimum dimensions for ballroom designation are a thickness (perpendicular to strike) of 6 meters and a length of 5 meters (parallel to strike). Mineralization contacts are irregular but sharp and are characterized by a dramatic decrease in sulfide content (from one to two percent in ballrooms to only trace amounts, Whole rock major and trace element compositions of rocks from ballrooms exhibit a strong geochemical control by cumulus phases. There are no significant major or trace element differences in the rocks from the two ballroom types. Moreover, cumulate mineralogy in ballrooms shows no variation from cumulate mineralogy in the JM Reef. Magnesium, Fe, and Cr exhibit a strong correlation with one another and the other major elements but do not correlate with Cu, Ni, and S. This indicates that Cu, Ni, and S were controlled by processes other than those controlling the distribution of the major elements in cumulus phases. Cl-rich hydrous phases in the ballrooms (apatite and phlogopite) are evidence for the presence of Cl-rich fluids that interacted with melt in the mineralized zone, inferred to coincide with the growth of cumulus silicate phases. Pegmatitic textures also evidence the presence of fluid. The concentrated fluids played the major role in the formation of these anomalously rich ore morphologies. This fluid likely originated when intercumulate melt became fluid saturated during crystallization of the cumulate pile at the base of the magma chamber and migrated upward as Boudreau (1999) suggests. This fluid appears to have been concentrated in some areas to form locally enriched areas of PGE mineralization (ballrooms). Areas of extensive fluid-melt interaction could produce type 2 ballrooms, while type 1 ballrooms were formed where there was little or no melt present when the upwelling fluid became sulfide saturated. The fluid generation and migration may have been caused by an eruption of flood lava from the crystallizing magma chamber. It is possible that even a small eruption from the chamber could generate a large enough pressure decease to induce fluid saturation in the melt remaining in the cumulate pile. This process may have repeated each time lava erupted from the evolving chamber and created multiple sulfide horizons in the Stillwater Complex. Evidence of sulfide remobilization and low temperature secondary alteration is abundant in ballrooms. The secondary alteration phases include sericite, zoisite/clinozoisite, serpentine, magnetite, pyrite, talc, and chlorite. A regional metamorphic event at 1.7 Ga that changed the Pb isotopic composition of the sulfides is likely the cause of the alteration. This low temperature hydrothermal event locally remobilized sulfides, chalcophile elements, and PGEs in the J-M Reef and ballrooms and may have variably depleted or enriched parts of the mineralization. This remobilization of sulfides, chalcophile elements, and PGEs has had a significant influence on the local distribution (centimeters to a few meters) of PGE bearing sulfides.

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Nanoparticles made from platinum-group metals (PGMs) have demonstrated effectiveness as inorganic, artificial peroxidase mimics. These artificial enzymes boast several advantages over natural peroxidases, including superior catalytic efficiency, chemothermal stability, and cost effectiveness. PGM nanoparticles are therefore increasingly coming into use over protein-based enzymes across a variety of sectors, including public health, medical diagnostics, environmental protection, and automotive manufacturing. However, the full range of PGM nanoparticles with potential for these applications have not yet been systematically compared. Such a comparison will be significantly beneficial to future design of PGM nanoparticles, and their optimization as catalysts for industry. The present study aims to address this need through the systematic characterization and analysis of one type of PGM nanoparticle. Research of this type will greatly improve the future effectiveness of similar particles within their respective applications. In particular, this work focuses on palladium (Pd), a metal with an extensive history of use as an inorganic catalyst of organic reactions. The first phase of the study focuses on development of a reliable method for synthesis of Pd nanoparticles smaller than 10 nm, beginning with accepted procedures for the development of similar particles. The second involves a thorough characterization of the particles, using X-ray photoelectron spectroscopy (XPS) for elemental composition, transmission electron microscopy (TEM) for morphology, X-ray diffraction (XRD) for confirmation of surface facets, infrared spectroscopy (IRS) for confirmation of citrate surface ligand, and high-resolution TEM for single crystal structure. In the third phase, the particles will be tested for catalytic activity as artificial peroxidases in the oxidation of 3,3’,5,5’-tetramethylbenzadine (TMB) by hydrogen peroxide.

No description available.