Rare earths and copper systems were studied using X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS). The use of monochromased synchrotron radiation and improved energy resolution for RIXS made possible to obtain valuable information on the electronic structure in 4f, 5f and 3d systems. Experimental results for rare-earths (Ho, Gd, Cm,U, Np, Pu) were analyzed by atomic multiplet theory based on the Hartree-Fock calculations. The inelastic scattering structures in RIXS spectra at 5d edge of actinides found to be sensitive to actinide oxidation states in different systems. Comparison of experimental and calculated Cm 5d RIXS spectra gave direct information about valency of the 248-curium isotope in oxide. Scientific understanding of processes that control chemical changes of radioactive species from spent fuel is improved by studying interactions of actinide ions (U, Np, Pu) with corroded iron surfaces. RIXS measurements at the actinide 5d edge indicate the reduction of U(VI), Np (V) and Pu (VI) to U(IV), Np(IV) and Pu (IV) by presence of iron ions. This thesis is also addressed to the study of changes in the electronic structure of copper films during interaction with synthetic groundwater solutions. The surface modifications induced by chemical reactions of oxidized 100Å Cu films with Cl−, SO42− and HCO3– ions in aqueous solutions with various concentrations were studied in-situ using XAS. It was shown that the pH value, the concentration of Cl− ion and presence of HCO3– ion in the solutions strongly affect the speed of the corrosion reaction. The Cu 2p RIXS was used to distinguish between the species present on the copper surface while in contact with groundwater solution.

In his programmatic article More Is Different (1972), Nobel laureate P. W. Anderson captured the fundamental interest in quantum matter in a nutshell. The central motive in this field is emergence. In the inaugural volume of the homonymous journal, J. Goldstein defined this as "the arising of novel and coherent structures, patterns and properties during the process of self-organization in complex systems". Famously, the idea that the "the whole is greater than the sum of its parts" goes back to Aristotle's metaphysics, and it has served as a stimulating concept in 19th century biology, economics and philosophy. The study of emergence in condensed matter physics is unique in that the underlying complex systems are sufficiently "simple" to be modelled from first principles. Notably, the emergent phenomena discovered in this field, such as high-temperature superconductivity, giant magnetoresistance, and strong permanent magnetism have had an enormous impact on technology, and thus, society. Historically, there has been a distinction between materials with localized, strongly interacting (or correlated) electrons - and non-interacting, itinerant electronic states. In the last decade, several new states of matter have been discovered, which emerge not from correlations, but from peculiar symmetries (or topology) of itinerant electronic states. The term quantum materials has therefore become popular to subsume these two strands of condensed matter physics: Electronic correlations and topology. In this thesis, I report investigations of four quantum materials which each illustrate present key interests in the field: The mechanism of high temperature superconductivity, the search for materials that combine both electronic correlations and non-trivial topology and novel emergent phenomena that arise from the synergy of electronic correlations and a strong coupling of spin- and orbital degrees of freedom. The common factor and potential key to understanding these materials is magnetism. My experimental work is focused on neutron and x-ray scattering techniques, which are able to determine both order and dynamics of magnetic states at the atomic scale. I illustrate the full scope of these methods with experimental studies at neutron and synchrotron radiation facilities. This includes both diffraction and spectroscopy, of either single- or polycrystalline samples. My in-depth analysis of each dataset is aided by structural, magnetic and charge transport experiments. Thus, I provide a quantitative characterization of magnetic fluctuations in an iron-based superconductor and in two Dirac materials, and determine the magnetic order in a Dirac semimetal candidate and a complex oxide. As a whole, these results demonstrate the elegant complementarity of modern scattering techniques. Although such methods have a venerable history, they are presently developing at a rapid pace. Several results of this thesis have only been enabled by very recent instrumental advances.

Transformation of amorphous calcium phosphate (ACP) and brushite into hydroxylapatite, an important biomineral, has been documented. The relationships between synthesis conditions and the formation and transformation of these phases are not comprehensively understood. The metastable nature of ACP has made it historically challenging to investigate, and many analyses attempt to stabilize the phase through drying or including additional ions or proteins in the reaction. In situ investigations provide an incisive approach to examining the structure and transformation of ACP and brushite as a function of synthesis conditions. The first project develops a new method for in situ analyses of the structure of ACP and brushite shortly after reagent mixing, without chemical stabilization. This method was used in the second project to examine how the initial Ca/P affects ACP structure and transformation. Our results identify the first structural differences in types of ACP, controlled by the initial Ca/P. At ratio 0.2 the Ca – P bonding geometry is primarily monodentate, ratio 5.0 produces a coordination that is primarily bidentate, and there is a mix of monodentate and bidentate coordinates at intermediate ratios between the two. These results are independent of system pH between the examined range of 6-11. Further ex situ transformation experiments identified that at ratio 0.2, ACP transformed directly into hydroxylapatite, but at higher ratios the transformation product is brushite. This is a promising mechanism for direct ACP to hydroxylapatite conversion at a biologically relevant pH. In the final project, the statistically significant synthesis parameters (age, pH, temperature, supersaturation, and initial ion ratio) for ACP, brushite, and hydroxylapatite formation are evaluated. Binary logistic regression analysis and nonlinear continuous logistic regression analysis are applied to a dataset compiled from the literature. Equations were developed that predict the percentage of ACP and brushite that will form. The equations and significant variables seem to depend on the transformation pathway of brushite and ACP. The current analysis did not comprehensively describe hydroxylapatite formation when trying to concurrently evaluate the ACP to hydroxylapatite and brushite to hydroxylapatite pathways. Taken together, these studies provide new ways to study and interpret calcium phosphate phases as they form and transform. Experiments identified new relationships between the chemistry and structure of ACP. The new in situ experimental method and the equations we developed can be used to improve future experimental designs towards a comprehensive understanding of the calcium phosphate system. / Doctor of Philosophy / Hydroxylapatite is a mineral made of calcium and phosphate, that is similar to the mineral components of bones and teeth in humans and other mammals and fish. Hydroxylapatite and other calcium phosphate phases can form when solutions, rich in calcium and phosphate, are mixed. Phases without long-range crystal structure, are amorphous calcium phosphates (ACP). Additional calcium phosphate minerals, like brushite can also form. If brushite and ACP are left in solution, they will transform into hydroxylapatite over time. Major questions include the need to learn the short-range atomic structure of ACP and how ACP and brushite transform into hydroxylapatite In this dissertation, I investigate how chemistry and other variables such as age and time impact the calcium phosphate phase to form and how it transforms with aging. The first project develops a new method to study the structure of ACP and brushite without drying the study materials or adding additional chemicals or proteins to prevent them from transforming. The sample forms in a solution and flows directly through an X-ray beam for structural analysis. This method is used in project two to examine how the ratio of calcium and phosphate in the beginning of the reaction affected the structure of ACP and how it transformed. The results identify the first structural differences in types of ACP, controlled by the initial Ca/P. At a ratio of 0.2 a calcium and phosphorus atom mostly share only one oxygen between them, but at Ca/P = 5.0, they mostly share two oxygens. At ratios in between 0.2 and 5.0 they share a mix of one and two oxygens. The results are independent of pH. Additionally, at ratio 0.2, ACP transformed directly into hydroxylapatite, but at all other ratios it transformed to brushite. Investigations of direct ACP to hydroxylapatite transformation are usually performed at a pH above that found in humans, but the transformation at low ratio occurred at a biologically relevant pH. In the final project statistical analysis was used to identify what synthesis conditions (out of age, pH, temperature, supersaturation, and initial ion ratio) had a significant impact on the formation of ACP, brushite, and hydroxylapatite. Equations were developed that can be used to predict the percentage of ACP and brushite that form based on the statistically significant variables. The current analysis did not fully describe hydroxylapatite formation. Results suggest separate equations are needed for hydroxylapatite forming directly from ACP and directly from brushite. Combined, these studies have created new ways to study calcium phosphate phases as they form and transform. This work experimentally identified new relationships between the chemistry and structure of ACP. Both the method and equations will help researchers improve their future experimental designs so investigations can be more directly compared to create a comprehensive understanding of calcium phosphates.

The staling of baked products remains a significant cause of economic loss due to the loss of enjoyment seen as crumb firming occurs. The aims of the current project have been to investigate the stability of amylases in bakery formulations. In addition, the impact of partial hydrolysis products of starch on staling is investigated. Specific assays were used to measure ƒÑ-amylase and ƒÒ-amylase, in the presence of the other potentially interfering activity. ƒÑ-Amylase activity levels appeared to gradually increase during the proofing stages and then to decline upon heating of the dough. However, the activity remaining in the final baked loaf was readily measurable indicating that not all of the enzyme had been inactivated. Free and total ƒÒ-amylase activities were also measured and most was found to be in the free form. ƒÒ-Amylase was unstable with only relatively low activities remaining in the final baked loaf. It appears that of the two amylolytic enzymes, ƒÑ-a mylase is sufficiently stable that it may exert some impact on the crumb characteristics in the freshly baked product and during subsequent storage. In order to assess the likelihood that amylolysis is of significance to crumb characteristics, HPLC was used to analyse aqueous extracts for sugars. Commercial flours were found to contain low levels of sugars with maltose being the predominant sugar present. A number of commercial breads were also analysed and the composition found to vary between the different samples. Typically maltose was present at higher levels than the other sugars. When experimental loaves were analysed, the patterns showed that other sugars declined during proofing whereas maltose remained at readily measurable levels. Upon baking and subsequent storage the amounts of maltose increased. These results are consistent with the findings that some amylolytic activity remains in the baked product. In the third phase of this study, a potential means of investigating the role of particular carb ohydrates in product textures and staling rates was examined. The approach of spray drying was used to prepare microencapsulated maltodextrin. The encapsulating agents used were based upon rice starch and guar galactomannan. When these microcapsules were incorporated into the breadmaking formulation and baked, it appeared that softer crumb characteristics were achieved. The data also indicates an effect of delay in the staling rates. In a preliminary evaluation of the potential of two X-ray scattering methods, it was found that both techniques appear useful. The differences seen for samples of bread crumb analysed at various stages of storage did not show large differences in the intensity patterns. Of the two approaches, small angle analysis (SAXS) appears to show greater potential for application in ongoing studies of staling. In conclusion, cereal grain ƒÑ-amylase may be more stable during breadmaking than previously thought. There appears to be an increase in the level of some low molecular weight sugars in the final, baked product. Microencapsulation may offer a useful technique for the study of the role of specific carbohydrates during baking and storage of breads.

QC 20100629

Thesis (PhD)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: John W. Peters. Includes bibliographical references (leaves 131-147).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1951. / Typescript with manuscript equations. Vita. Includes as (Part III): Multiple diffuse small sngle acettering of x-rays / David L. Dexter and W.W. Beeman. Reprinted from Physical review, vol. 76, no. 12 (15 Dec. 1949), p. 1782-1786. Includes bibliographical references.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18778号 / 理博第4036号 / 新制||理||1581(附属図書館) / 31729 / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 松田 和博, 教授 八尾 誠, 教授 田中 耕一郎 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

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