Dissertations / Theses on the topic 'X-ray diffraction analyses'
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Tsuboi, Chiaki. "X-ray crystal structure analyses of magnetically oriented microcrystalline suspensions." Kyoto University, 2016. http://hdl.handle.net/2433/216190.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第19936号
農博第2186号
新制||農||1044(附属図書館)
学位論文||H28||N5009(農学部図書室)
33022
京都大学大学院農学研究科森林科学専攻
(主査)教授 木村 恒久, 教授 西尾 嘉之, 教授 髙野 俊幸
学位規則第4条第1項該当
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Bilton, Clair. "Hydrogen bonding in organic systems : a study using X-ray and neutron diffraction and database analyses." Thesis, Durham University, 1999. http://etheses.dur.ac.uk/4795/.
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This thesis covers three topics related to the field of crystal engineering. Three different approaches to improving the understanding of hydrogen bonding are covered; analysis of a family of related molecules, investigations of specific functional groups and a systematic, data-driven study of intramolecular hydrogen bonding patterns. Chapters 2 to 4 and chapter 11 cover the background theory to the different methods used to obtain the data discussed in the remainder of the thesis. X-ray and neutron diffraction techniques are discussed, along with sections describing the Cambridge Structural Database, which was used as a data source throughout this work, and a brief section on intermolecular forces. Crystal structure analyses of seventeen gem-alkynol molecules are given in chapters 5 to 10. The gem-alkynol functionality is particularly interesting for a study of intermolecular interactions as it is a combination of both a strong and weak hydrogen bonding group. The group of molecules was investigated with the aim of locating robust supramolecular motifs. The group is subdivided into sections containing molecules with similar structures and their packing patterns are discussed. The second experimental section, chapters 12 and 13, comprises statistical studies into the function of the azido and cyano functional groups as hydrogen bond acceptors. The technique used was to use the Cambridge Structural Database as a data source for the main analysis, then complement the results with simple theoretical calculations. The remaining chapter, 14, describes a systematic analysis of intermolecular hydrogen bonded motifs. A data-driven approach was designed which allows direct comparison of motifs by means of a probability ordered list.
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Parris, Juanita M. "X-ray diffraction analyses of synthetic polymers in the 3,3-substituted polyoxetane family and their copolymers." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39373.
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A series of crystalline, substituted polyoxetanes were studied using X-ray fibre diffraction as the primary investigative tool. Three systems were probed, each presenting a unique facet of structure analyses.The structure of poly(3,3-bis(hydroxymethyl)oxetane) using X-ray fibre diffraction was proposed. Modelling studies and FT-IR have been used to arrive at a probable conformation in which the backbone was found to be planar zigzag and the hydroxyls in the sidechain were extended. Few reflections were observed and it was not possible to grow lamellar single crystals for electron diffraction.
The preliminary structure of poly(3,3-bis(hydroxymethyl)oxetane) diacetate using X-ray fibre diffraction on films and fibres and electron diffraction on lamellar single crystals provided a tentative packing scheme based on the most intense equatorial reflections. CP/MAS $ sp{13}$C NMR indicates slight deviations in the environments for the acetate groups on the same residue.
X-ray fibre diffraction of atactic P(MHMO) resulted in a unit cell of comparable dimensions as in P(BHMO). The intensity and quality of the fibre patterns suggest identical structures. P(BHMO-co-MHMO) is a random copolymer in which the MHMO units are incorporated into the crystalline lattice of P(BHMO). One melting endotherm is observed for all compositions and decreases linearly with increasing content of MHMO. These data support a phenomenon known as isomorphism.
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Seeley, Jack R. "Optical and X-Ray Diffraction Analyses of Shock Metamorphosed Knox Group Dolostone from Wells Creek Crater, Tennessee." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou152597581946267.
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Zhiou, Seifeddine. "Réaction à l'état solide d'un film mince de Ni(Co) avec InGaAs : analyses microstructurales." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY067/document.
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Cette thèse porte sur l’analyse microstructurale d’intermétalliques formés par réaction à l’état solide entre une couche mince de métal Ni(Co) et un substrat d’InGaAs et s’inscrit dans le cadre du développement de reprises de contact pour les dispositifs MOSFET sub-10 nm ou les applications photoniques. Ce travail comporte une partie relative au développement d’une méthodologie de diffraction des rayons x adaptée à ces composés très texturés et deux parties distinctes où nous décrivons et discutons les résultats expérimentaux.L’étude microstructurale (phase, texture…) des intermétalliques obtenus par réaction à l’état solide est rendue complexe par la formation transitoire de phases métastables, non stœchiométriques parfois, contraintes mécaniquement, et présentant en général des orientations cristallines (texture cristallographique) très marquées. Du fait de cette complexité microstructurale, ces intermétalliques n’ont souvent pas été caractérisés de façon complète et peu de connaissances se trouvent sur leur structure et leur formation. Aussi, et pour caractériser de façon complète et sans omettre des phases ou des orientations dans le système Ni-In-Ga-As, nous avons contribué au développement d’une méthode de mesure globale et rapide par diffraction des rayons X permettant de reconstruire une cartographie large 3D de l’espace réciproque. Les données recueillies par cette méthode sont reconstruites afin d’extraire soit des diagrammes de diffraction dits « détexturés », soit des figures de pôle…permettant une analyse semi quantitative de la microstructure des échantillons.Dans la première partie des résultats expérimentaux, nous nous intéressons à la caractérisation des intermétalliques formés à partir d’empilements Ni/InGaAs/InP recuits ex-situ à différentes températures. Nous décrivons la formation des intermétalliques, leurs textures, et leurs paramètres structuraux. Nous relevons certains aspects de la microstructure qui évoluent en fonction de la température de recuit comme l’anisotropie de texture, la stœchiométrie des intermétalliques et le domaine d’existence thermique et nous proposons des hypothèses qui peuvent expliquer l’évolution de ces phénomènes. Cette première étude faite sur des substrats InP a été confrontée aux résultats obtenus pour des intermétalliques similaires réalisés sur substrats InGaAs/GaAs/Si. En effet, les substrats Si sont les substrats industriellement ciblés pour la réalisation de composés logiques à canal III-V à grande échelle (sur des plaquettes de 300mm de diamètre). Ensuite, nous avons comparé la métallisation de la couche d’InGaAs dans le cas de Ni pur avec la métallisation d’InGaAs lorsqu’un élément d’alliage (Co) est ajouté à la couche de Ni. Ainsi, l’analyse microstructurale révèle des différences notamment sur les textures qui ont été interprétées sur la base de considérations thermodynamiques, mais aussi structurales comme l’alignement des deux couches entre elles, liées à des aspects plus cinétiques.Dans la deuxième partie de ce travail, nous présentons les résultats des analyses in situ effectuées par cartographies de l’espace réciproque en 3D au synchrotron ESRF à Grenoble. Il s’agit de suivre en temps réel par diffraction des rayons X, les réactions à l’état solide des échantillons du type Ni (7 nm et 20 nm)/InGaAs/InP et Ni0.9Co0.1 (20 nm)/InGaAs/InP lors de recuits par rampes... Ensuite, nous avons effectué des recuits isothermes sur les échantillons de type Ni (20 nm)/InGaAs/InP. Ces différentes mesures, couplées avec des hypothèses sur la croissance nous ont permis d’extraire les paramètres cinétiques relatifs à la formation de la première phase d’intermétallique. Les textures observées et leur évolution lors des recuits thermiques in situ sont différents des recuits ex situ. Ceci peut notamment être expliqué par un mode de recuit différent dans le cas in situ où la cinétique du système est plus lente, favorisant ainsi les structures et textures les plus stablesThis thesis focuses on the microstructural analysis of intermetallics formed by solid-state reaction between a thin layer of Ni (Co) metal and an InGaAs substrate and was carried out in the framework of contact development for sub-10 nm MOSFET but have also photonic applications. This work includes a part related to the development of an X-ray diffraction methodology adapted to highly textured compounds and two distinct parts in which we describe and discuss the experimental results.The microstructural study (phase, texture ...) of intermetallics obtained by solid-state reaction is complicated due to the formation of transient metastable, often non-stoichiometric and mechanically stressed phases. These phases have generally very marked crystalline orientations (crystallographic texture). Because of this microstructural complexity, these intermetallic have often been not fully characterized and there is little knowledge about their structure and formation. Moreover, and to fully characterize the Ni-In-Ga-As system without omitting phases or textures, we have contributed to the development of a comprehensive method of rapid measurement by X-ray diffraction to reconstruct large 3D maps of the reciprocal space. The collected data through this method are reconstructed to extract either diffraction diagrams called "detextured" diagrams or pole figures ... which allows a semi-quantitative analysis of the intermetallic microstructure.In the first part of the experimental results, we focus on the characterization of intermetallic formed through Ni / InGaAs / InP stacks and annealed ex situ at different temperatures. We describe the formation of the intermetallics, textures, and structural parameters. We note some aspects which vary depending on the annealing temperature such as the texture anisotropy, the stoichiometry of intermetallic and range of thermal existence and propose hypotheses that can explain the evolution of these phenomena. The studies on InP substrates were compared to results obtained for similar intermetallic made on GaAs / Si substrates. Indeed, the Si substrates are targeted for industrials to achieve logic compounds III-V channel large-scale (on 300 mm wafers). Then, we compared the metallization of the InGaAs layer in the case of pure Ni metallization with the results when an alloying element (cobalt) was added to the Ni layer. The microstructural analysis revealed several differences especially texture differences. These differences were interpreted on the basis of thermodynamic considerations, but also on the basis of structural alignment of the two layers together which are also linked to more kinetic aspects.In the second part of this work, we present the analysis results of studies performed by in situ 3D Reciprocal Space Mapping on the ESRF synchrotron in Grenoble. We followed the formation and stability of the intermetallics by real-time X-ray diffraction measurements, for different kind of samples: Ni (7 nm and 20 nm) / InGaAs / InP and Ni0.9Co0.1 (20nm) / InGaAs / InP, using ramp annealing... Then, we performed isothermal annealings for Ni(20 nm) / InGaAs / InP samples. These measurements, coupled with assumptions on the intermetallic growth, allowed us to extract the kinetic parameters for the formation of the first phase of the intermetallic. The observed textures and their evolution during in situ thermal annealings are different than ex situ annealing. This can be explained by a different mode of annealing in the case of in situ where the kinetics of the system is slower, thus favoring the most stable structures and textures
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Song, Guangjie. "Structure analyses of cellobiose and cellulose using X-ray diffraction and solid-state NMR spectroscopy on oriented samples." Kyoto University, 2015. http://hdl.handle.net/2433/199362.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第19038号
農博第2116号
新制||農||1031(附属図書館)
学位論文||H27||N4920(農学部図書室)
31989
京都大学大学院農学研究科森林科学専攻
(主査)教授 木村 恒久, 教授 西尾 嘉之, 教授 髙野 俊幸
学位規則第4条第1項該当
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Uchida, Hinako. "CRYSTAL CHEMICAL AND STRUCTURAL ANALYSES OF SOME COMMON ROCK-FORMING MINERALS: SPINEL, KALSILITE, CLINOPYROXENE AND OLIVINE." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/194999.
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Natural and synthetic common-rock forming minerals were examined using single-crystal X-ray diffraction (SXRD) and electron microprobe (EMP) analyses. The influences of common defect features, such as inclusions in spinel and oxygen positional disorder and twinning in kalsilite, were reported on the respective structures. The case studies show that these defect features could lead to a misinterpretation of X-ray intensity data. The structural interpretations obtained from these XSRD analyses could be significantly different when physical properties of the crystals are considered.In the second part of my dissertation, comparative crystal chemical studies on mantle-derived minerals such as spinel, clinopyroxene, and olivine are reported. These studies were carried out to examine temperature, pressure, and compositional effects on the structures of these phases. In particular, packing arrangements of oxygen atoms were examined in detail to investigate how the packing affects element partitioning among upper-mantle minerals. At ambient conditions, oxygen packing is more distorted in the order of spinel < olivine < clinopyroxene. The packing of oxygen atoms in olivine might have a significant control on element substitutions at high pressure. Because elements whose radius is larger than that of Mg distort the packing of mantle olivine (Fo~89), olivine might limit the amount of those elements, such as Fe2+, entering the structure. In contrast, substitutions of smaller cations in C2/c clinopyroxenes increase packing distortion. For clinopyroxenes enclosed in peridotite and eclogite, higher equilibration pressures are associated with more distorted, less efficiently packed structures. Unlike many minerals reported in Thompson and Downs (2001), spinel becomes more packed with rising temperature when intracrystalline cation exchange reactions are possible. Despite wide chemical variations, spinel samples from one geological environment display a constant packing distortion, which might suggest that spinel is capable of achieving an optimal packing configuration at a given P and T.
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Stuart, Kevin L. "Discovery of Possible Paleotsunami Deposits in Pangandaran and Adipala, Java, Indonesia Using Grain Size, XRD, and 14C Analyses." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6719.
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Grain size, 14C age, and X-ray diffraction (XRD) analyses of sediments indicate possible tsunami deposits on the southern coast of Java near Pangandaran and Adipala. Previous studies that have described known recent and paleotsunami deposits were used for comparison. Fining-upward grain size trends, interbedded sand and mud, sediment composition, and trends in heavy mineral abundances are among the characteristics used for tsunami deposit identification. At Batu Kalde, an archaeological site south of Pangandaran, a layer of aragonitic sand with marine fossils was found atop a layer of archaeological fragments at an elevation of ~2-5 m. It is likely this layer was deposited by a tsunami, potentially generated by a mega-thrust earthquake. Archaeological material remains suggest that the tsunami occurred ~1300 years ago. A bivalve with an age of 5584-5456 cal YBP was buried within the deposit, perhaps long after its death. At Goa Panggung, a cave east of Batu Kalde, fining-upward grain size trends, composition of sediments, and radiocarbon ages suggest the presence of at least one tsunami deposit. A 5040-4864 cal YBP piece of charcoal overlying modern organic matter suggest that the tsunami first scoured the cave floor, reworking existing material and making interpretation difficult. At Adipala, in western Central Java, fining-upward grain size, upward decrease in heavy mineral abundances, and lateral continuity of sand layers revealed the existence of two possible tsunami deposits buried within the sediments in a swale ~1.6 km from the ocean. Age of the deposits is undetermined.
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Aubin, Marlène. "Révéler la chimie des préparations antiques, à usage cosmétique ou médical, impliquant des sels de métaux lourds." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066479/document.
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Dès l'Antiquité, les oculistes, médecins spécialisés dans le soin des yeux, utilisaient des médicaments solides sophistiqués appelés collyres. Ils étaient composés de substances minérales, végétales et animales. Ce travail résulte d'une collaboration interdisciplinaire destinée à préciser la composition chimique et les structures des phases inorganiques ainsi que les procédés de fabrication de ces collyres. Les techniques analytiques mises en œuvre sont la spectroscopie Raman, la spectrométrie de fluorescence des rayons X (XRF) et la diffraction des rayons X (XRD). L'étude de la stabilité de réplicas à base de sels métalliques (plomb, zinc, cuivre, fer), fréquemment mentionnés dans les textes antiques, a permis de préciser les phases initialement présentes dans ces médicaments. Quatre collections de collyres archéologiques (Musée Gallo-Romain de Lyon, Musée d'Archéologie Nationale, Cabinet des Médailles de la BnF, Musée Atestino d'Este) ont été étudiées sur site au moyen d'instruments portables. Une méthodologie, combinant les résultats obtenus par XRF et par XRD, a été développée afin d'obtenir les proportions entre les phases inorganiques présentes. Les compositions obtenues par analyses physico-chimiques ont ainsi été comparées aux compositions décrites dans les textes anciens et, pour la première fois, des liens entre les deux ont été établisIn the Antiquity, oculists (eye care specialised physicians) mixed mineral, vegetal and animal substances to prepare elaborate solid medicines termed collyria. In an interdisciplinary work, we investigated the chemical composition, the inorganic phases structure and the manufacturing process of such collyria. The implemented analytical techniques were Raman spectroscopy, X-ray fluorescence (XRF) and X-ray diffraction (XRD). The stability of metallic salts based replicas prepared according to ancient texts recipes was studied in order to identify the pristine phases. Four collections of archaeological collyria (Musée Gallo-Romain de Lyon, Musée d’Archéologie Nationale, Cabinet des Médailles de la BnF, Musée Atestino d’Este) were studied on site, using portable devices. A methodology combining XRF and XRD results was developed to quantify the inorganic phases distribution. For the first time, a straight relationship was established between compositions obtained by physico-chemical analysis and ancient recipes
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Sinangil, Mehmet Selcuk. "Estimation of crystal size and inhomogeneous strain in polymers using single peak analysis." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/19096.
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Griffiths, Jennifer Ann. "X-ray diffraction measurements for breast tissue analysis." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444776/.
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Biological tissues exhibit elastic x-ray scatter properties unique to individual tissue types. It has been suggested that these properties could be exploited in the discrimination of tissues in diagnostic radiology, particularly in mammographic imaging. The work in this thesis investigates the elastic scatter from human breast tissues with a view to moving the Diffraction Enhanced Breast Imaging (DEBI) technique towards the clinical domain. Instrumentation was considered in terms of a suitable scatter detector and its associated collimation. A phosphor coated low-light-level CCD in conjunction with a parallel hole array collimator was introduced as a possible angular dispersive diffraction detector, and conically collimated HPGe was found to be a suitable detector for energy dispersive diffraction. Diffraction imaging was achieved using both planar and tomographic imaging techniques. The planar imaging considered the spatial resolution needed for clinically useful results and showed that depth information of the order of 1 cm can easily be obtained using diffraction imaging techniques. A micro-tomographic diffraction imaging technique was used to further present knowledge of the 'scatter signatures' of human breast tissue. The tissue is naturally inhomogeneous, so precise knowledge of a sample's composition is needed in order to accurately classify its scatter signature. A total of twenty seven breast tissue samples were examined, covering a range of tissue types, with nineteen of these samples being extensively studied. The microCT produced diffraction images of the inhomogeneous tissue samples and their diffraction signatures were related to the results of conventional histopathological analysis. A correlation was observed between the predominant tissue type in a sample and the ratio of the intensity of the sample's scatter at momentum transfers of 1.1 and 1.5 nm-1. A Student's t-test performed on these results gave the probability of a null hypothesis for correlation of less than 1%.
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Tian, Yu. "X-ray Diffraction Analysis of with Hydrogen Interstitials." Thesis, Uppsala universitet, Materialfysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-353796.
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Barium Zirconate is a material valuable in many aspects. Among all the significant characteristics of (BZO), the possibility of hydrogen interstitials is of great importance. With the help of X-ray diffraction analysis, many kinds of structure-related information of a crystal sample can be collected. In this thesis, the XRD pattern of hydrogen induced expansion and contraction of oxygen atoms in the BZO perovskite lattice is investigated both experimentally and theoretically.
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Catteaux, Rémy. "Étude de bioverres sol-gel à base de SiO2, CaO, Na2O, P2O5 et dopés à l'argent." Thesis, Valenciennes, 2015. http://www.theses.fr/2015VALE0011/document.
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Les bioverres du système quaternaire SiO2-CaO-Na2O-P2O5 obtenus par fusion doivent être coulés à 1400°C, ce qui ne permet pas la mise en forme de matériaux complexes comme par exemple des composites macroporeux en biocéramiques (HA et TCP) recouverts d’une couche uniforme de bioverre. Pour contourner cette limitation, la voie sol-gel a été utilisée dans cette étude. Le but principal a été de synthétiser par le procédé sol-gel, deux compositions quaternaires du système SiO2-CaO-Na2O-P2O5 habituellement obtenues par fusion. Il s’agit des compositions 45S5® de L.L. Hench et 47Q de C. Duée. Ces verres sont inversés, c’est à dire qu’ils contiennent plus d’éléments modificateurs (calcium et sodium) que d’éléments formateurs (silicium et phosphore). Pour la synthèse sol-gel, du TEOS (TétraEthylOrthoSilicate) et du TEP (TriEthylPhosphate) ont été utilisés pour introduire les formateurs. En utilisant des précurseurs minéraux pour le calcium et le sodium, il existe des difficultés à maintenir le gel amorphe lors de son séchage. En effet, les précurseurs minéraux sont le siège de mécanismes de dissolution-précipitation liés entre autres aux solvants choisis, à la nature et à la concentration des anions dans le milieu. L’étude s’est donc orientée vers l’utilisation d’autres précurseurs des modificateurs afin de limiter la part des anions qui contribuent au phénomène de précipitation non souhaité. Deux procédés de synthèse originaux ont été alors mis au point avec des précurseurs alcoolates, acétates et du glycérol. Avec ces procédés, la nature amorphe des composés a été confirmée et leurs caractéristiques thermiques ont été ensuite étudiées. Tous les verres sol-gel réalisés sont bioactifs. Les compositions de base, 45S5® et 47Q, ont été ensuite dopées avec de l’argent afin de doter les bioverres d’une action antibactérienne. Des cellules L132 ont été utilisées pour évaluer la toxicité des poudres des deux procédés solgel. Le procédé le moins toxique a été conservé pour la suite de l’étude. Les bioverres dopés et non dopés ont été alors déposés à la surface d’échantillons plats et macroporeux en HA et TCP par une technique de trempage-retrait. Des tests de prolifération et de formation de biofilms par Pseudomonas aeruginosa ont été réalisés sur des pastilles de TCP recouvertes et ont mis en évidence un effet toxique des dépôts contenant de l’argent. Des mesures de prolifération et de vitalité sur des cellules humaines MG63 ont été également réalisées et ont permis d’observer également un effet toxique. Cet effet n’est pas souhaitable dans ce cas car il affecte la biocompatibilité de l’implant. Il devrait cependant être confirmé par d’autres tests réalisés avec d’autres lignées cellulairesBioglasses of quaternary system SiO2-Na2O-CaO-P2O5 obtained by melting are cast at 1400 ° C, which does not allow the shape of complex materials, for example macroporous bioceramics composites (HA and TCP) coated with an uniform layer of bioglass. To overcome this limitation, the sol-gel process has been used in this study. The aim has been to synthesize by sol-gel process, two quaternary compositions usually obtained by melting in the SiO2- CaO-Na2O-P2O5 system. These are two compositions: 45S5® of L.L. Hench and 47Q made by C. Duée. These glasses are reversed, ie they contain more modifiers elements (calcium and sodium) as formers elements (silicon and phosphorus). For the sol-gel synthesis, TEOS (TetraEthylOrthoSilicate) and TEP (TriEthylPhosphate) have been used to introduce the formers. When minerals precursors are used for calcium and sodium, there are difficulties to maintain amorphous the gel during its drying. Indeed, minerals precursors have some dissolution-precipitation mechanisms linked to the selected solvents and the nature and concentration of anions in the medium. The use of other modifiers precursors has been made in the study to limit the proportion of anions contributing to the undesired precipitation phenomenon. Two original synthesis methods have been developed with alkoxide precursors, acetates and glycerol. With these processes, the amorphous nature of the compounds has been confirmed and their thermal characteristics have been studied. All sol-gel glasses are bioactives. The compositions, 45S5® and 47Q, have been doped with silver to add an antibacterial action to the bioglasses. L132 cells have been used to test the toxicity on the powders of the two sol-gel processes. The least toxic process is has been retained for the other tests. Doped and undoped bioglasses have been coated on the surface of flat and macroporous samples of HA and TCP by a dip-coating technique. Proliferation tests and biofilms formation by Pseudomonas aeruginosa have been made on coated TCP and show toxic effects of silver. Proliferation and vitality tests have been also made on MG63 human cells and have allowed to observe a toxic effect. This effect is not suitable in this case because it affects the biocompatibility of the implant. It would, however, be confirmed by other tests with other cell lines
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Davydok, Anton [Verfasser]. "X-ray diffraction analysis of InAs nanowires / Anton Davydok." Siegen : Universitätsbibliothek der Universität Siegen, 2013. http://d-nb.info/1044457511/34.
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Rajkumar, Ganeshalingam. "X-ray diffraction analysis and modelling of polycrystalline fibres." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487950.
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This thesis concerns the development of software techniques for polycrystalline fibre diffraction analysis and the application of the techniques to the determination of the structures of target molecules. Fibre diffraction analysis is one of a powerful method for determining the structure of polycrystalline fibres. However, one of the main shortcomings of this method is the paucity of intensity data; the observed intensities need to be modelled using suitable methods. This particular problem is further complicated by the fact that no direct Fourier synthesis methods can be used because of the cylindrical averaging inherent in fibre diffraction patterns. An attractive strategy is to use software programs for performing semi-automated data extraction from fibre diffraction patterns using refined method of data stripping and modelling. Even though there are some software packages available to do part of this, process the best one, the CCP13 suite, required a great deal of improvement and development. In this thesis, the design, development and applicability of such a software package, FibreFix, are described. Using several practical examples, we show how this software package has aided in solving practical structure-determination problems. Covered in the thesis are: (i) Development,of several techniques as part of the CCP13 software for performing data stripping and structure analysis; (ii) Design and development of a new integrated CCP13 software package, FibreFix, incorporating these techniques; (iii) Evaluation of FibreFix to show that the analysis and modelling processes in data reduction for fibre diffraction can be simplified substantially using the FibreFix software. To show this two different, but related, case studies are described: crystalline natural rubber and E-DNA. Our results show that the structures modelled by the software package are well above our threshold for satisfactory modelling. This claim is supported by very satisfactory X-ray amplitude fitness and in reduction in the R-factor of the models. We have analysed the structure of oriented natural rubber, obtaining a very good fit with the observed X-ray amplitudes and a best R factor of 0.18. We have also analysed different possible models for E-DNA. The R-factors indicate that 172 D-DNA-like models are better than 152 models. We have a found a satisfactory structure for E-DNA, which gives a good fit with the X-ray amplitudes and a best R-factor 0f 28%. This project has substantially, improved the CCP13 fibre analysis software, now all incorporated within FibreFix, which can be used for data stripping of many forms of fibre diffraction pattern. The structures of rubber and E-DNA have also been used as targets to utilize and enhance the capability of the LALS (linked atom least-squares) modelling and refinement program.
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Mhiri, Akram. "Elaborations, caractérisations et études spectroscopiques des composés hybrides organiques-inorganiques R2SnBr6 avec R=N(CH3)4 et R=N(CH3-CH2)4." Thesis, Le Mans, 2020. http://www.theses.fr/2020LEMA1032.
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Ce travail s'est inscrit dans le cadre d’un projet de recherche qui vise à synthétiser et caractériser de nouveaux matériaux hybrides organiques-inorganiques pouvant être utilisés dans la fabrication de cellules photovoltaïques, mais avec des éléments moins polluants que les composés actuellement proposés. Pour cela nous avons élaboré et étudié deux nouveaux composés à base d'étain : le bis tétraméthylammonium hexabromostannate ([N(CH₃)₄]₂SnBr₆), et le bis-tétraéthylammonium hexabromostannate ([CH₃-CH₂]₄SnBr₆). Les études expérimentales sont basées sur des analyses thermiques (ATD, DSC, ATG), la spectrométrie par dispersion en énergie (EDX), la diffraction de rayons X sur poudre et sur monocristal, les spectrométries vibrationnelles (infrarouge et Raman), la spectrométrie d’impédance complexe et la spectrométrie UV-Visible.Il est apparu que [N(CH₃)₄]₂SnBr₆ est de symétrie cubique du type K₂PtCl₆. Il est constitué d'octaèdres SnBr₆²- non connectés entre eux, séparés par des tétraméthylammoniums, pouvant être considéré comme dérivé d'une structure pérovskite dans laquelle la moitié des sites de symétrie octaédriques sont occupés par des SnBr₆²- et la moitié par des lacunes (structure pérovskite 0D). Cet arrangement laisse ainsi de très larges volumes libres de tout atome, et nous avons même montré qu'il présente des canaux ouverts infinis de large section (0,5 nm de diamètre), pouvant ainsi être considéré comme poreux. Les analyses vibrationnelles couplées à des calculs ab-initio sur l'octaèdre SnBr₆²- et l'ion tétraméthylammonium (TMA+) ont permis d'expliquer sans ambiguïté les spectres et de conclure à l'existence de désordre local. Les signaux infrarouges, Raman et EDX suggèrent aussi la présence d’OH- ou d’'eau, probablement en relation avec la structure lacunaire. Il a été montré que le composé subit une transition de phase réversible à plus haute température (vers 100°C). Les études vibrationnelles confirment la transition de phase, de même que les études des propriétés diélectriques. Le gap (2,31 eV) est proche de la largeur de la bande interdite 2,7 eV du semi-conducteur Cs₂SnBr₆ utilisé dans les cellules solaires.Le bis-tétraéthylammonium hexabromostannate [CH₃-CH₂]₄SnBr₆ à température ambiante présente une structure (rhomboédrique) composée également d'octaèdres SnBr₆²- non connectés, mais d'arrangement structural compact, contrairement au composé au TMA. Son étude en température révèle deux transitions réversibles mais avec fortes hystérésis à 262K/239K et à 362K/307K (chauffage/refroidissement). Son énergie de gap est égale à 2,51 eVThis work is part of a research project that aims to synthesize and characterize new organic-inorganic hybrid materials that can be used in the manufacture of photovoltaic cells, but with less polluting elements than the compounds currently proposed. For this we have developed and studied two new compounds based on tin : bis tetramethylammonium hexabromostannate ([N(CH₃)₄]₂SnBr₆), and bis-tetraethylammonium hexabromostannate ([CH₃-CH₂]₄SnBr₆). The experimental studies are based on thermal measurements (ATD, DSC, ATG), energy dispersion spectrometry (EDX), powder and single crystal X-ray diffraction, vibrational spectrometries (infrared and Raman), complex impedance spectrometry, and UV-Visible spectrometry.It appeared that [N(CH₃)₄]₂SnBr₆ is of cubic symmetry of the K₂PtCl₆ type. It consists of unconnected SnBr₆²- octahedra, separated by tetramethylammoniums, which can be considered to be derived from a perovskite structure in which half of the sites of octahedral symmetry are occupied by SnBr₆²- and half by vacancies (perovskite structure 0D). This arrangement thus leaves very large volumes free of any atom, and we have even shown that it has infinite open channels of large section (0,5 nm in diameter) ; it can thus be considered as a porous material. The vibrational analyzes coupled with ab-initio calculations on the SnBr₆²- octahedron and the tetramethylammonium ion (TMA+) made it possible to unambiguously explain the spectra and to conclude to the existence of local disorder. Infrared, Raman and EDX signals also suggest the presence of OH- or water, probably related to the porous structure. It has been shown that the compound undergoes a reversible phase transition at a higher temperature (around 100°C). Vibrational studies confirm the phase transition, as do studies of dielectric properties. The gap (2,31 eV) is close to the width of the 2,7 eV forbidden band of the Cs₂SnBr₆ semiconductor used in solar cells.Bis-tetraethylammonium hexabromostannate [CH₃-CH₂]₄SnBr₆ at room temperature exhibits a (rhombohedral) structure also composed of non-connected SnBr₆²- octahedra, but of compact structural arrangement, unlike the compound with TMA. Its temperature study reveals two reversible transitions but with strong hysteresis at 262K / 239K and at 362K / 307K (heating / cooling). Its gap energy is equal to 2,51 eV
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Murphy, Caitlin Anne. "An analysis of a continuum X-ray Diffraction/Fluorescence instrument." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/114332.
Full textAbstract:
Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 40-41).
Scientists at NASA's Goddard Space Flight Center have developed a Combined X-ray Diffraction/Fluorescence (CXRDF) instrument. CXRDF performs simultaneous chemical and structural analysis of an unprepared sample, making it ideal for planetary mineral identification. In an effort to analyze the effectiveness of CXRDF, samples were chosen from a list of minerals that are important in the debate about the origin of the outcrops at Meridiani Planum on Mars. These samples were run on both CXRDF and a laboratory X-ray diffractometer. The datasets were compared, looking at peak identification, d-spacing resolution, and whether the instruments could definitively identify each sample. CXRDF successfully measured the d-spacings for each mineral, and the chemical analysis data were very valuable. However, for CXRDF to be able to definitively identify minerals, its d-spacing range and resolution will need to be improved, in addition to its data analysis software.
by Caitlin A. Murphy.
S.B.
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Turner, Stuart Matthew Robert. "Novel X-ray diffraction and the remote analysis of Mars." Thesis, University of Leicester, 2017. http://hdl.handle.net/2381/39449.
Full textAbstract:
The scientific exploration of Mars is currently being undertaken with the goals: to determine if Mars ever supported life; to understand the past and present climate; and to understand the evolution of its surface and interior. To achieve these goals, orbital and in-situ exploration of Mars is required. Detailed orbital high-resolution hyperspectral, image and topographic datasets enable the identification of areas of scientific interest on the surface of Mars. In-situ measurements are then taken by planetary landers and rovers to characterise the environment in great detail. This thesis has used orbital datasets to investigate impact craters on Mars, and has also focused on the development of a novel X-ray diffraction instrument technique that could be used to characterise the surface of Mars in-situ. The study of post-Noachian impact craters with hyperspectral data returned by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), highlighted two impact craters that may have hosted an impact-induced hydrothermal system. One of these impact craters shows spectral evidence for the presence of the mineral prehnite (Ca2Al2Si3O10(OH)2) that likely formed as a result of impact-induced hydrothermal activity, and might have provided a habitable environment for microbial life. A novel back-reflection X-ray diffraction technique that is uniquely insensitive to sample morphology, facilitating the analysis of unprepared whole-rock samples, was successfully tested on a range of samples from rock-forming minerals to carbonates, sulphates and phyllosilicates. A range of experimental facilities were utilised in this work, including a beamline at the Diamond Light Source synchrotron facility where the technique was further validated in a high-resolution configuration. The work presented in this thesis exemplifies the identification of an area of scientific interest on Mars, and the extensive testing and development of an instrument technique that could be used to geologically characterise such an identified area in-situ.
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Kumari, Maini S. M. "Development of a breast tissue diffraction analysis system using energy dispersive X-ray diffraction." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1370578/.
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Research groups have shown that diffraction techniques could be applied for characterising materials. In particular, Energy Dispersive X-ray Diffraction (EDXRD) technique has been successfully used in characterising materials such as plastics, drugs and biological tissues. The size of breast tissues used for characterisation so far has been small, in the range of mm. In order to exploit the fullness of the EDXRD technique in characterising breast tissues and hence enable early and precise breast tumour detection, the presented research work takes the existing research work a step forward by developing a breast tissue diffraction analysis system wherein breast-sized tissue-equivalent materials have been studied for tumour detection and an optimised EDXRD system for breast tissue analysis has been presented. For the development of this breast tissue analysis diffraction system, a ray-tracing model of the EDXRD system has been developed. The model has been used to predict diffraction spectra. These model predictions have been further used to optimize system parameters for an EDXRD system so it could be used for breastsized samples. Materials like plastics, pharmaceutical drugs and tissues have been characterised on this optimized system. The diffraction spectra collected have been used to build a diffraction spectrum database which has been further used to generate diffraction images for detection of tumour of size as small as 0.5 cm. Following this abstract, in the thesis, Chapter 1 introduces how X-rays interact with matter and what research groups have achieved so far in breast tissue diffraction. Ray-tracing model of EDXRD system forms Chapter 2 wherein the system parameters along with the corrections used in the model and model predictions have been presented. The characterisation of materials using optimized EDXRD system has been detailed in Chapter 3. Chapter 4 elaborates the generation of diffraction images. Chapter 5 presents the conclusions and suggests future work. The thesis ends with a list of references.
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Dent, A. J. "The development of anomalous (resonance) X-ray diffraction techniques for solution." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384555.
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Hey, Jakob. "From X-ray diffraction data annealing to comprehensive charge density analysis." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://hdl.handle.net/11858/00-1735-0000-0001-BBE1-7.
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Bohndiek, Sarah Elizabeth. "Active pixel sensors for breast biopsy analysis using X-ray diffraction." Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1444112/.
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Breast cancer diagnosis currently requires biopsy samples to be analysed by a histopathologist a time consuming, highly specialised process. X-ray diffraction is a quantitative technique that can distinguish between healthy and diseased breast biopsy samples using the change in proportions of fat and fibrous tissue that occurs when cancer invades. A semi-automated breast biopsy analysis system based on X-ray diffraction could yield a faster patient diagnosis. Recording X-ray diffraction patterns is a challenging task needing low noise, large area, and wide dynamic range detectors. Scientific complementary metal oxide semiconductor (CMOS) Active Pixel Sensors will soon be able to meet all of these demands in a single device. Characterization of two novel Active Pixel Sensors that advance towards an ideal X-ray diffraction detector is presented. 'Vanilla' exhibits a low read noise of 55e r.m.s. and high quantum efficiency of up to 70% so was selected for the design and implementation of the first 'Active Pixel X-ray Diffraction' (APXRD) system. Following on from Vanilla, the 'Large Area Sensor' (LAS) covered an area of over 29cm2 and had a wide dynamic range of over 95dB. The first linear systems model of an Active Pixel Flat Panel Imager (scintillator coupled APS) was formulated in the design of the APXRD system, to select filters to narrow the spectral width of the X-ray beam and predict the recorded scatter intensity. Following system implementation, scatter signatures were recorded for numerous breast tissue equivalent samples. A multivariate analysis model calibrated with these was able to predict the percentage fat content of an 'unknown' sample to within 3% a very promising result. The width of the filtered polychromatic X-ray spectrum had only a minor influence on the APXRD scatter signatures indicating that the system preserves all relevant structural information.
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Joyce, Anne-Marie. "Analysis of Metallurgically Bonded Electrospark Deposited Coatings." ScholarWorks@UNO, 2019. https://scholarworks.uno.edu/td/2670.
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Molina, Cathy. "Incorporating Electrochemistry and X-ray Diffraction Experiments Into an Undergraduate Instrumental Analysis Course." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115123/.
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Experiments were designed for an undergraduate instrumental analysis laboratory course, two in X-ray diffraction and two in electrochemistry. Those techniques were chosen due their underrepresentation in the Journal of Chemical Education. Paint samples (experiment 1) and pennies (experiment 2) were characterized using x-ray diffraction to teach students how to identify different metals and compounds in a sample. in the third experiment, copper from a penny was used to perform stripping analyses at different deposition times. As the deposition time increases, the current of the stripping peak also increases. the area under the stripping peak gives the number of coulombs passed, which allows students to calculate the mass of copper deposited on the electrode surface. the fourth experiment was on the effects of variable scan rates on a chemical system. This type of experiment gives valuable mechanistic information about the chemical system being studied.
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Bray, Lois Marie. "Petrographic, X-ray diffraction, and chemical analysis of pottery from Anyang, China /." Diss., ON-CAMPUS Access For University of Minnesota, Twin Cities Click on "Connect to Digital Dissertations", 2001. http://www.lib.umn.edu/articles/proquest.phtml.
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Huang, Pao-Cheng. "Analysis of single-crystal semiconductor thin film structure by x-ray diffraction." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/20145.
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Ibrahim, Marcelle. "Étude du comportement mécanique d’UO2 implanté en helium par micro-diffraction des rayons X et modélisation par éléments finis." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1140/document.
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Dans le but d'étudier le comportement mécanique du combustible nucléaire dans un scénario de stockage direct à long terme, des polycristaux d'UO2 sont implantés en ions Hélium dans une fine couche surfacique (environ 1 µm), induisant des déformations. Ces déformations sont mesurées, à l'échelle des grains, par micro-diffraction des rayons X, en utilisant un rayonnement synchrotron (ESRF). Des méthodes d'analyse d'images sont développées pour traiter automatiquement le grand nombre de clichés de diffraction. Le développement d'outils statistiques permet de détecter des clichés problématiques et d'améliorer la précision de l'analyse. Pour des faibles profondeurs d'implantation, l'interaction mécanique entre les grains peut être négligée. Les résultats expérimentaux peuvent être approchés par un modèle mécanique simple. À plus grandes profondeurs, les résultats expérimentaux montrent une plus grande interaction mécanique aux joints de grain qui peut être modélisée par éléments finis. Des outils de géostatistique ont été utilisés pour quantifier ces interactions. Le gonflement et les constantes élastiques de la couche implantée peuvent être ajustés à travers les déformations mesurées sur un grand nombre de grains d'orientations différentes. Ces études permettent de déterminer le gonflement du combustible nucléaire en conditions d'irradiation, ainsi que les modifications de ses propriétés élastiquesIn order to study the mechanical behavior of nuclear fuel during direct long term storage, UO2 polycrystals were implanted with Helium ions at a thin surface layer (1 µm approximately), which leads to stress and strain fields in the layer. Strains were measured, at the grains scale, by X-ray micro-diffraction, using synchrotron radiation (ESRF). Image analysis methods were developed for an automatic analysis of the large number of diffraction patterns. Applying statistical tools to Laue patterns allows an automatic detection of low quality images, and enhances the measurement precision. At low layer thickness, the mechanical interaction between grains can be neglected. At higher thickness, experimental results showed a higher mechanical interaction near grain boundaries that can be modeled using finite elements method. Geostatistical tools were used to quantify these interactions. The swelling and the elastic constants in the implanted layer can be estimated through the measured strains on a large number of grains with different orientations. This work allows the determination of the swelling of nuclear fuel in irradiation conditions, as well as the modification of its elastic properties
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Rachwal, James D. "X-ray diffraction applications in thin films and (100) silicon substrate stress analysis." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/1745.
Full textAbstract:
Silicon is used as a substrate for X-ray mirrors for correct imaging. The substrate needs to be mechanically bent to produce a certain curvature in order to condition and focus the X-ray beam. The X-rays impinge a mirror at very shallow angles, in order to reduce the amount of intensity loss in the diffraction process. The X-ray mirrors need to be bent to an extremely precise profile, and even small distortions from this profile can reduce the effectiveness of the X-ray mirrors. The X-rays that impinge on the mirror also produce large amounts of heat that can change the temperature of the substrate, resulting in its thermal expansion and distortion. By measuring the distortions in-situ caused by these temperature changes it may be possible to correct for these errors. A four-point bending fixture was designed for in-situ X-ray bending experiments in order to measure the distortions to the (100) silicon sample caused by the bending setup.
By being able to measure the distortion caused by the setup, in like manner it would be possible to measure distortion caused by thermal expansion. Several alignments were needed in order to obtain accurate results, including adding copper powder on top of the sample. The copper powder that was added is not under stress, and therefore will not shift its reflection peak when the sample is under bending stress, thus serving as a reference in order to make corrections. The strain results were then compared to values calculated from mechanical deflections from bending. Despite the efforts to control accuracy, a significant variation appeared in the values when the top surface was in compression. As an alternative an IONIC stress-gauge was used to measure the deflections of the sample rather than calculate them.
Another alternative was to calculate the deflection of the substrate by first determining the stress in the layer deposited onto the mirror's substrate by using sin²psi technique, then using Stoney's equation to determine the change in curvature of the substrate, with the stress in the layer being known. Several tests were performed to demonstrate the ability to measure these deflections.
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Intisar, Amir. "A portable CCD array detector for in-situ analysis of powder samples using combined X-ray diffraction/X-ray fluorescence techniques." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4401.
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This work describes the design, development and testing of a portable charge-coupled device detector system to be used for the simultaneous collection of X-ray diffraction and X-ray fluorescence data from powdered samples. The detector was designed for both terrestrial and extra-terrestrial applications that require in-situ analysis of samples, where access to a laboratory instrument is restricted. The detector system incorporates 4 e2v technologies CCD30-11 devices, employing multi-phase pinned technology for low noise operation. Geometrical calculations and thermal studies concerning the design of the detector are presented, with particular emphasis on motivations for the chosen geometry. Initial characterisation and calibration of the detector was performed in a laboratory environment using a purpose built test facility. The test facility included a high brightness X-ray micro-source from Bede Scientific Instruments, coupled with an XOS polycapillary collimating optic, which was used to deliver a focused beam of low divergent X-rays to the sample. The design of the test facility is discussed and the spectra and flux produced by the X-ray micro-source are investigated. The operational performance of the detector is highlighted and the use of the instrument in different applications is described, namely the planetary sciences and pharmaceuticals sector. Finally, based on the knowledge gained from initial testing of the instrument, improvements to the detector design are outlined, which greatly enhance the combined X-ray diffraction/X-ray fluorescence performance of the instrument.
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Seymour, Thomas. "Synchrotron X-ray diffraction peak profile analysis of neutron- and proton-irradiated zirconium alloys." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/synchrotron-xray-diffraction-peak-profile-analysis-of-neutron-and-protonirradiated-zirconium-alloys(5765de34-361d-4a74-a9b0-22eb047dd6f3).html.
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One of the degradation processes of zirconium-based nuclear fuel assemblies is irradiation-induced growth, an anisotropic, stress-independent, macroscopic deformation mechanism that elongates fuel cladding tubes axially. Irradiation-induced growth is driven by the irradiation-induced formation of dislocation loops, where the evolution of the loop structure can be complex, with the initial formation of loop generating transient growth, while the later formation of component dislocation loops, or loops, leads to accelerated growth. A full mechanistic understanding of loop nucleation is as yet unforthcoming. This thesis utilizes the diffraction peak broadening analysis software, named extended Convolutional Multiple Whole Profile, to study the dislocation structure evolution of neutron- and proton-irradiated zirconium alloys in order to validate proton-irradiation as a effective tool for the study of irradiation damage in relation to irradiation-induced growth. The diffraction profiles obtained exhibit unexpected features present in the tails of the Bragg peaks, tentatively attributed here to either strained regions of matrix, or diffuse scattering from severely distorted regions around nucleating precipitates, both originating from an increased solute concentration. The diffraction results indicate that the proton-irradiated samples exhibit qualitatively similar behaviours as seen from neutron-irradiation, such as a threshold irradiation dose before the formation of loops, however, a continued increase of loop dislocation density determined from peak broadening analysis is not observed by transmission electron microscopy. It is also shown that the Nb-containing Low-Sn ZIRLO® alloy has a lower dislocation density than the Nb-free Zircaloy-2 after the formation of loops correlating well with the relative irradiation-induced growth behaviours observed in- reactor. A correlation between a reduction in the loop dislocation density and the formation of loops is observed in Low-Sn ZIRLO® and Zr-1.60Sn-0.033Fe, providing support for the hypothesis that vacancy loops transform into loops. Zr- 0.61Sn-0.024Fe and Zr-1.60Sn-0.033Fe alloys show a rapid increase in the loop dislocation density in the initial stages of proton-irradiation, likely due to the low irradiation-resistance of the precipitates present in these alloys.
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Гордієнко, Олена Володимирівна, Елена Владимировна Гордиенко, Olena Volodymyrivna Hordiienko, Ольга Сергіївна Ярмоленкo, Ольга Сергеевна Ярмоленко, Olha Serhiivna Yarmolenkо, and El Falougy H. "Age-related features of hydroxyapatite structure in a spongy bone tissue." Thesis, Comenius University of Bratislava, 2018. https://essuir.sumdu.edu.ua/handle/123456789/85447.
Full textAbstract:
The structure and size of hydroxyapatite depend on age. X-ray diffraction analysis helps to determine age-related features of hydroxyapatite structure in a spongy bone tissue. Comparing the obtained data with literature data (6,7,8), the ontogenetic transformations in spongy bone tissue can be divided into several periods:
1) period of intensive osteogenesis - in immature age;
2) stabilization period is in mature animals;
3) period of regressive changes with the predominance of resorption processes in old rats.
The mineral component of the calcaneus matrix in laboratory rats of different age groups is characterized by changes at the microstructural level. An increasing in crystallite size rises the level of microdeformation of the crystal lattice. Defective increase, i.e. structural imperfection of biominerals, indicates violations of normal metabolic processes in the calcaneus, which in turn leads to a decrease in its strength.
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Hofmann, Felix. "Probing the deformation of ductile polycrystals by synchrotron X-ray micro-diffraction." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:4a5db5b9-1673-40bf-a25f-2e09a572a108.
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Microscopic beams of penetrating synchrotron radiation provide a unique tool for the analysis of material structure and deformation. This thesis describes my contributions to the development of new synchrotron X-ray micro-beam diffraction experimental techniques and data interpretation, and the use of experimental results for the validation of material deformation models. To study deeply buried material volumes in thick samples, the micro-beam Laue technique was extended to higher photon energies. Through-thickness resolution was achieved either by a wire scanning approach similar to Differential Aperture X-ray Microscopy (DAXM), or by applying tomographic reconstruction principles to grain-specific Laue pattern intensity. Both techniques gave promising first results. For reliable micro-beam Laue diffraction measurements of elastic strains in individual grains of a polycrystal, understanding of the error sources is vital. A novel simulation-based error analysis framework allowed the assessment of individual contributions to the total measurement error. This provides a rational basis for the further improvement of experimental setups. For direct comparison of experimental measurements and dislocation dynamics simulations, diffraction post-processing of dislocation models in two and three dimensions was developed. Simulated diffraction patterns of two-dimensional dislocation cell/wall type structures captured correctly some of the features observed experimentally in reciprocal space maps of a large-grained, lightly deformed aluminium alloy sample. Crystal lattice rotations computed from three-dimensional dislocation dynamics simulations of a Frank-Read source showed anisotropic orientation spread similar to that observed in micro-beam Laue experiments. For the experimental study of crystal lattice distortion, a novel technique was proposed that combines micro-beam Laue diffraction with scanning white-beam topography. Diffraction topography allows the study of lattice rotation at scales smaller than the scanning beam size. The new technique makes it possible to apply classical topography methods to deformed samples.
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Prestidge, M. C. "Data analysis and processing in X-ray diffraction studies from myosin heads in muscle." Thesis, Open University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292345.
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Vanhamme, Géraldine. "Etude de la réactivité des alitiers du haut-fourneau dans les ciments de type CEM III." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209956.
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En Europe, suite à la fermeture de nombreux sites sidérurgiques, une utilisation croissante de laitiers de haut-fourneau d’origine et d’âge variés voit le jour depuis plusieurs années. Cette évolution conduit à une diversification de la composition chimique et minéralogique des laitiers. Connaître l’influence de ces caractéristiques sur la réactivité des laitiers utilisés en substitution du clinker dans les ciments de haut-fourneau (CEM III) devient, dès lors, primordial pour assurer les performances de tels ciments.Dans ce contexte, le présent travail a pour but d’investiguer l’influence de la composition chimique et de l’âge des laitiers sur leur réactivité tant par des essais physico-mécaniques que par une caractérisation physico-chimique et minéralogique de CEM III/B à différentes échéances d’hydratation. L’effet néfaste du vieillissement des laitiers est clairement mis en exergue et son impact diffère selon la composition chimique de départ du laitier. Les ions aluminium engendrent une accélération de l’hydratation et une amélioration des résistances physico-mécaniques à jeune âge mais, à long terme, ils conduisent à une perte de ces dernières. Concernant l’influence des ions titane dans les laitiers, la tendance générale observée est une diminution des performances physico-mécaniques.
Sur base de ces résultats, une évaluation de la représentativité de moyens accélérés d’estimation de la réactivité des laitiers est effectuée. Il est mis en évidence que seules les mesures de résistances physico-mécaniques classiques permettent d’évaluer correctement la réactivité des différents laitiers.
Une évaluation de la détermination de la teneur en constituants de CEM III/B par la méthode Rietveld est menée par comparaison avec la méthode de dissolution sélective de la norme EN 196-4 et le dosage des constituants par pesée. Moyennant une utilisation adaptée de cette méthode, les résultats obtenus à l’aide de celle-ci sont très encourageants.
In Europe, following the closure of many steel plants, an increased use of blast furnace slag (BFS) of various age and origin was born for several years. This evolution leads to a diversification of the chemical and mineralogical composition of the BFS. Knowing the influence of these characteristics on the reactivity of slag used in substitution of clinker in blast-furnace cement (CEM III) becomes, therefore, crucial to ensure the performance of such cements.
In this context, this work aims to investigate the influence of chemical composition and age of BFS on their reactivity by both physico-mechanical and physico-chemical and mineralogical characterization of CEM III/B at different times of hydration. The adverse effect of ageing of BFS is clearly highlighted and its impact varies depending on the chemical composition of the BFS. Aluminum ions generate an acceleration of the hydration and improve mechanical strength at early age, but at long term, they lead to a loss of the strength. Regarding the influence of titanium ions in the BFS, the general trend is a decrease of the physical and mechanical performance.
Based on these results, an assessment of the representativeness of accelerated means of estimating, the BFS reactivity is done. It is emphasized that only measures of physical and conventional mechanical strength can accurately assess the reactivity of different BFS.
An evaluation of the determination of the amount of CEM III/B components by the Rietveld method is based upon comparison with the selective dissolution method from the EN 196-4 norm and components determination by weight. Through appropriate use of this method, the results obtained are very encouraging.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Yoon, Chunhong. "Image Analysis and Diffraction by the Myosin Lattice of Vertebrate Muscle." Thesis, University of Canterbury. Electrical and Computer Engineering, 2008. http://hdl.handle.net/10092/1899.
Full textAbstract:
Closely packed myosin filaments are an example of a disordered biological array responsible for the contraction of muscle. X-ray fiber diffraction data is used to study these biomolecular assemblies but the inherent disorder in muscle makes interpretation of the
diffraction data difficult. Limited knowledge of the precise nature of the myosin lattice disorder and its effects on X-ray diffraction data is currently limiting advances in studies on muscle structure and function.
This thesis covers theoretical and computational efforts to incorporate the myosin lattice disorder in X-ray diffraction analysis. An automated image analysis program is developed
to rapidly and accurately quantitate the disorder from electron micrographs of muscle cross-sections. The observed disorder is modelled as an antiferromagnetic Ising model and the model verified using Monte Carlo simulations. Theory and methods are developed for efficient calculation of cylindrically averaged X-ray diffraction from two-dimensional
lattices that incorporate this disorder.
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MELO, ADEILSON P. de. "Caracterização do jade e dos silicatos da familia do jade para aplicação em dosimetria das radiações." reponame:Repositório Institucional do IPEN, 2007. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11550.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Köhl, Martin [Verfasser], and T. [Akademischer Betreuer] Baumbach. "Analysis of nanostructures based on diffraction of X-ray radiation / Martin Köhl. Betreuer: T. Baumbach." Karlsruhe : KIT-Bibliothek, 2014. http://d-nb.info/1065732163/34.
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Tusche, Christian Alexander. "A surface X-ray diffraction analysis of reactive and non-reactive metal metal oxide interfaces." Berlin Logos-Verl, 2007. http://d-nb.info/987720155/04.
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Loveridge, Andrew. "Quantitative analysis of shock propagation in crystals by use of time resolved x-ray diffraction." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249492.
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Cook, Emily Jane. "Analysis of energy dispersive x-ray diffraction profiles for material identification, imaging and system control." Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1446057/.
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This thesis presents the analysis of low angle X-ray scatter measurements taken with an energy dispersive system for substance identification, imaging and system control. Diffraction measurements were made on illicit drugs, which have pseudo- crystalline structures and thus produce diffraction patterns comprising a se ries of sharp peaks. Though the diffraction profiles of each drug are visually characteristic, automated detection systems require a substance identification algorithm, and multivariate analysis was selected as suitable. The software was trained with measured diffraction data from 60 samples covering 7 illicit drugs and 5 common cutting agents, collected with a range of statistical qual ities and used to predict the content of 7 unknown samples. In all cases the constituents were identified correctly and the contents predicted to within 15%. Soft tissues exhibit broad peaks in their diffraction patterns. Diffraction data were collected from formalin fixed breast tissue samples and used to gen erate images. Maximum contrast between healthy and suspicious regions was achieved using momentum transfer windows 1.04-1.10 and 1.84-1.90 nm_1. The resulting images had an average contrast of 24.6% and 38.9% compared to the corresponding transmission X-ray images (18.3%). The data was used to simulate the feedback for an adaptive imaging system and the ratio of the aforementioned momentum transfer regions found to be an excellent pa rameter. Investigation into the effects of formalin fixation on human breast tissue and animal tissue equivalents indicated that fixation in standard 10% buffered formalin does not alter the diffraction profiles of tissue in the mo mentum transfer regions examined, though 100% unbuffered formalin affects the profile of porcine muscle tissue (a substitute for glandular and tumourous tissue), though fat is unaffected.
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Chandril, Sandeep. "In situ structural and compositional analysis using RHEED electrons induced x-rays." Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10641.
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Thesis (Ph. D.)--West Virginia University, 2009.Title from document title page. Document formatted into pages; contains ix, 97 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 95-97).
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Beyerlein, Kenneth Roy. "Simulation and modeling of the powder diffraction pattern from nanoparticles: studying the influence of surface strain." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41211.
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Accurate statistical characterization of nanomaterials is crucial for their use in emerging technologies. This work investigates how different structural characteristics of metal nanoparticles influence the line profiles of the corresponding powder diffraction pattern. The effects of crystallite size, shape, lattice dynamics, and surface strain are all systematically studied in terms of their impact on the line profiles.
The studied patterns are simulated from atomistic models of nanoparticles via the Debye function. This approach allows for the existing theories of diffraction to be tested, and extended, in an effort to improve the characterization of small crystallites. It also begins to allow for the incorporation of atomistic simulations into the field of diffraction. Molecular dynamics simulations are shown to be effective in generating realistic structural models and dynamics of an atomic system, and are then used to study the observed features in the powder diffraction pattern.
Furthermore, the characterization of a sample of shape controlled Pt nanoparticles is carried out through the use of a developed Debye function analysis routine in an effort to determine the predominant particle shape. The results of this modeling are shown to be in good agreement with complementary characterization methods, like transmission electron microscopy and cyclic voltammetry.
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Watts, Michael Robert. "The analysis of diffraction measurements of internal strains in metal matrix composites." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313918.
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SOUZA, JULIANA P. de. "Estudo da sinterização de vidros aluminossilicatos por calorimetria exploratória diferencial." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23660.
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Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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SCAPIN, MARCOS A. "Aplicacao da difracao e fluorescencia de raios X (WDXRF): ensaios em argilominerais." reponame:Repositório Institucional do IPEN, 2003. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11251.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Bassi, Andrea Li. "X-ray and light scattering from nanostructured thin films." Thesis, Durham University, 2000. http://etheses.dur.ac.uk/4631/.
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The object of this thesis is the study of nanostructured thin films using inelastic fight scattering and elastic x-ray scattering techniques. Their use in combination with other techniques is a powerful tool for the investigation of nanostructured materials. X-ray, Raman and Brillouin characterisation of cluster-assembled carbon films, promising for applications in the field of catalysis, hydrogen storage and field emission, is here presented. X-ray reflectivity (XRR) provided a measure of the density. Raman spectroscopy showed that the local bonding in these amorphous films depends on the size distribution of the clusters and that it is possible to select the cluster size in order to grow films with tailored properties. Brillouin scattering provided a characterisation at the mesoscopic scale and an estimate of the elastic constants, revealing a very soft material. XRR was employed to study density, layering and roughness of a wide range of amorphous carbon films grown with different techniques. Some films possess an internal layering due to plasma instabilities in the deposition apparatus. By comparing XRR with Electron Energy Loss Spectroscopy, a unique value for the electron "effective mass" was deduced and a general relationship between sp(^3)-content and density was found. XRR and H effusion were used to determine the hydrogen content. A study of the size-dependent melting temperature in tin nanoparticle thin films was undertaken with a combined use of X-Ray Diffraction (XRD) and light scattering. A redshift in the position of a Rayleigh peak in the temperature-dependent Brillouin measurements was shown to be related to the melting of the nanoparticles and explained by an effective medium model. XRD also provided information on the low-level of stress in the particles. Low-frequency Raman scattering was used to study the behaviour of the acoustic modes of a single particle as a function of temperature.
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Vine, David John. "New quantitative methods in analyser-based phase contrast X-ray imaging." Monash University. Faculty of Science. School of Physics, 2008. http://arrow.monash.edu.au/hdl/1959.1/57830.
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New quantitative methods are developed for analyser-based phase contrast imaging (ABI) with hard X-rays. In the first instance we show that quantitative ABI may be implemented using an extended incoherent source. Next, we outline how complex Green’s functions may be reconstructed from phase contrast images and we apply this method to reconstruct the thick perfect crystal Green’s function associated with an ABI imaging system. The use of quantitative ABI with incoherent X-ray sources is not widespread and the first set of results pertains to the feasibility of quantitative ABI imaging and phase retrieval using a rotating anode X-ray source. The necessary conditions for observation of ABI phase contrast are deduced from elementary coherence considerations and numerical simulations. We then focus on the problem of extracting quantitative information from ABI images recorded using an extended incoherent X-ray source. The results of an experiment performed at Friedrich-Schiller University, Germany using a rotating anode X-ray source demonstrate the validity of our approach. It is shown that quantitative information may be extracted from such images under quite general and practicable conditions. We then develop a new use for phase contrast imaging systems that allows the Green’s function associated with a linear shift-invariant imaging system to be deduced from two phase contrast images of a known weak object. This new approach is applied to X-ray crystallography where the development of efficient methods of inferring the phase of rocking curves is an important open problem. We show how the complex Green’s function describing Bragg reflection of a coherent scalar X-ray wavefield from a crystal may be recovered from a single image over a wide range of reciprocal space simultaneously. The solution we derive is fast, non-iterative and deterministic. When applied to crystalline structures for which the kinematic scattering approximation is valid, such as thin crystalline films, our technique is shown to solve the famous one-dimensional phase retrieval problem which allows us to directly invert the Green’s function to retrieve the depth-dependent interplanar spacing. Finally we implement our Green’s function retrieval method on experimental data collected at the SPring-8 synchrotron in Hyogo, Japan. In the experiment we recorded analyser-based phase contrast images of a known weak object using a thick perfect silicon analyser crystal. It is then demonstrated that these measurements can be inverted to recover the complex Green’s function associated with the analyser crystal Bragg peak. The reconstructed Green’s function is found to be in good agreement with the prediction of dynamical diffraction theory.
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Browne, Peter Anthony. "Determination of residual stress in engineering components using diffraction techniques." Thesis, University of Salford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365984.
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Zelaya, Carlos. "X-Ray Structure Analysis and Topological Charge Density Studies of Gossypol Derivatives." ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1841.
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Gossypol and gossypol derivatives are natural byproducts of a variety of cotton plant species that poses interesting chemical, biological, and medicinal properties that are currently heavily researched. Supporting evidence suggest that gossypol and gossypol derivatives act on the Bcl-2 proteins that have been linked to certain cancers. Gossypol amine derivatives, specifically, are actively researched and a variety of amine derivatives have already been synthesized. However, gossypol and its derivatives are challenging compounds to work with because many of its derivatives tend to exist in various tautomeric forms. When analyzing gossypol and its derivatives it is the complex electron configuration that dictates the chemical mechanism and biological activity. The following research provides a charge density study that describes in detail the electronic configuration via Bader's topological analysis of di(methoxy)gossypol and di(propylamino) gossypol. In addition, a series of crystallographic studies of gossypol amine derivatives and di(methoxy)gossypol are also analyzed.
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Moore, Zakhia. "Application of X-ray Diffraction Methods and Molecular Mechanics Simulations to Structure Determination and Cotton Fiber Analysis." ScholarWorks@UNO, 2008. http://scholarworks.uno.edu/td/888.
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The results of three very different studies are presented. X-ray diffraction has been utilized for single-crystal structure determinations, fiber diffraction analyses, and in conjunction with molecular modeling of Cellulose IIII. Although each technique is different in its sampling, data acquisition, data treatment, and identification, the common denominator has been the use of x-rays. The single-crystal structure determination of ethylene glycol bis(tropane-3-carboxylate) is presented as an example of the use of modern single-crystal x-ray instrumentation including the use of coupled charged devices (CCDs) as detectors for accurate data collection and rapid elucidation of crystal structures. The structure determination of Cellulose IIII by x-ray diffraction and computer modeling is presented to show how the use of x-rays in weakly diffracting materials can generate a reliable structure and be a key component in model building. Finally, a study is presented in which x-ray fiber diffraction data is utilized to investigate possible correlations between the crystallite orientation, crystallinity, crystallize size and the strength properties of cotton fibers collected from various countries.