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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 151 for “"powder diffraction"”.
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An Improved Flexible Neutron Detector For Powder Diffraction Experiments
… sources for neutron scattering. Neutron powder diffraction instruments will be an important element of these facilities and the incorporation of detectors into these instruments with a high neutron capture efficiency is desirable. A new detector design named the Flexible Embedded Fiber …
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Advances in the modelling of in-situ powder diffraction data
X-ray powder diffraction is a well-established technique to analyse structural and microstructural properties of materials. The possibility to record in-situ powder diffraction data allows studying changes within the structure and microstructure of a sample that occur in dependence on the applied …
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Structural studies using synchrotron X-ray powder diffraction and other techniques
… 1 gives an introduction to X-ray and neutron powder diffraction and the use of these techniques for crystal structure determination and refinement. The Rietveld structure refinement method is described and examples of different methods of structure determination from powder diffraction data …
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Molecular Dynamics and X-ray Powder Diffraction Simulations: Investigation of nano-polycrystalline microstructure at the atomic scale coupling local structure configurations and X-ray powder Diffraction techniques
… purpose of supporting the analysis of the X-ray powder diffraction patterns with a better, atomic level understanding of the studied system. Complex microstructures were generated with a new modified Voronoi tessellation method which provides a direct relation between generation parameters and …
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Monte Carlo Simulations of Powder Diffraction at Time-of-Flight Neutron Sources
Measured powder diffraction patterns contain contributions from the sample and the instrument. Most available data analysis software operates on the measured data to extract sample parameters, however, few programs can take sample parameters and rigorously simulate the expected diffraction profile …
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Quantification of fatigue damage in AISI 316L stainless steel using X-Ray powder diffraction (XRD)
… using a non-destructive examination Power X-ray diffraction (PXRD). In industry, the evaluation of material deformation post cycling loading is often performed using microscopic techniques such as transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD). However, each …
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The complementary use of theoretical structure prediction and X-ray powder diffraction data in crystal structure determination
… work was carried out by comparing the simulated powder diffraction patterns of theoretical predicted crystal structures of small organic materials with their experimental powder diffraction patterns, so that the experimentally identified structure could be automatically singled out from the many …
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Kristallstrukturuntersuchungen von Hauptgruppen-Nitriden mittels Pulverbeugung
… new nitrides and imides were investigated by powder diffraction methods. The crystal structures of a series of nitridophosphates and nitridocarbonates which were available only as powder were solved by direct methods after indexing and extraction of the integrated intensities. By neutron …
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Mixed anion complex hydrides for hydrogen storage
… Na\(_2\)BH\(_4\)NH\(_2\), have been solved by powder diffraction methods and characterised by infrared and Raman spectroscopy. The thermal decomposition of these hydrogen rich materials was investigated and hydrogen was observed as the major gaseous product in all cases. Ammonia was observed as …
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Compositional tuning, crystal growth, and magnetic properties of iron phosphate oxide
… iron atoms. This was based on neutron powder diffraction featuring unique broad, flat-topped magnetic reflections due to needle-like magnetic domains. In order to confirm the magnetic structure and origins of frustration, this thesis will expand upon the research focused on this …
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Preparation and Characterization of Solid Solutions of Ternary and Quaternary Antimony Oxides
… change and chemical modification. The beamline diffraction techniques, including synchrotron and neutron powder and single crystal diffraction techniques were employed as major techniques to investigate the structural and magnetic properties. The lab instrument techniques, including lab X-ray …
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The low-temperature formation of mixed-metal oxides
… and MoO₃ in air at room temperature. X-ray powder diffraction data show that the formation of highly crystalline Li₂MoO₄ is largely complete after 10 min, and that this product crystallises with the phenacite structuretype. This structure is the same as that derived from an X-ray diffraction …
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Synthesis and Properties of New Oxychalcogenide Materials
… used in this project. The theory behind the powder diffraction techniques used throughout is described, and information on specific methodology used in the data collections and analysis of this work is given. SQUID magnetometry is also discussed. Chapter 3 discusses the variable temperature …
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Magnetic ordering and spin wave dynamics in transition metal arsenides
… at different temperatures using neutron powder diffraction techniques, and using inelastic neutron scattering techniques to characterize exchange interactions in these materials. We discover a new ternary metallic arsenide Cu0.82Mn1.18As which crystallizes in the hexagonal crystal system …
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Synthesis and characterisation of metal oxides and fluorinated perovskite-related oxides
… nitrogen by the incorporation of cobalt. X-ray powder diffraction and Mossbauer spectroscopy show that in iron-rich systems the limited reduction of iron and cobalt leads to the segregation of discrete metallic phases without destruction of the perovskite structure. In cobalt-rich systems, the …
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High temperature studies of sodalites
… Characterisation by X-ray powder diffraction and Rietveld refinements showed that for the chloride and bromide systems the substitution of silver for sodium causes a contraction of the unit cell and M-X bonds in the MX4 tetrahedral units in the sodalite cages, with an …
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Experimental evaluation of polychromatic neutron diffraction
Neutron diffraction is a technique that allows scientists to measure the arrangement and motions of atoms in a crystalline lattice by observing neutrons scattering at angles that are characteristic of the interatomic distances of the crystal. This is useful for studying the response of crystals to …
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Advanced Characterization of Nanocrystalline Materials by Synchrotron Radiation X-ray Diffraction
… Among the possible spectroscopies, X-ray Diffraction (XRD) is especially suited to investigate materials at the nanoscale. However, to benefit of the full potential of SR XRD, a complete control of the diffracted signal is necessary, including the optics and general setâ up of the …
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Synthesis and characterisation of d-Bi2O3 related materials stabilised by substitutions of Ca, Ga, Nb and Re.
… of such materials, characterised by neutron powder diffraction, X-ray powder diffraction, electron diffraction, extended X-ray absorption of fine structure measurements, differential thermal analysis and impedance spectroscopy. The structure of two new fluorite-related materials, …
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A structural database for pharmaceutical salt selection
… were characterised by single crystal X-ray diffraction and their hydrogen bond interactions and molecular packing arrangements were examined using Mercury and XPac. This enabled the identification of robust hydrogen bonded synthons and supramolecular constructs for salts of secondary or …
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