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Showing 1 to 20 of 104 for “"exafs"”.
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Exafs Studies of Transition Metal Exchanged Zeolites
The extended X-ray absorption fine structure (EXAFS) that appears on the high energy side of the absorption edge of an element has been shown to be due to modifications to the final state wave function of the ejected photoelectron from the absorbing atom by its near neighbors.('1,2,3) Consequently, …
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EXAFS and Related Studies of Materials for Polymer Battery Use
… the polymer electrolyte morphology included DSC, EXAFS and VTPM. Impedance spectroscopy was employed to determine the sample conductivity as a function of temperature. The polymer electrolytes were of the form PEOn:MX2, where n represents the number of ethylene oxide repeat units associated with …
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Negative Thermal Expansion in Zincblende Structure: an EXAFS study of CdTe
… the local origin of NTE in zincblende crystals, EXAFS measurements have been performed on CdTe, which has NTE properties intermediate between Ge and CuCl. In this work an accurate evaluation of the bond thermal expansion, parallel and perpendicular MSRDs and distribution asymmetry of the first …
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Electrically Polarised Electrodes in DMSO and DMF electrolytes of Pseudohalide Salts: In situ IR studies supported by EXAFS/XANES and other techniques
… and extended X-ray absorption fine structure (EXAFS) were used to obtain direct information on the coordination state of electrogenerated products. From EXAFS/XANES data, the Ni(II)/NCS⁻ and NCSe⁻ complexes were confirmed to be octahedral bearing at least one monopseudohalide-ligand with the …
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Modeling Metal Protein Complexes from Experimental Extended X-ray Absorption Fine Structure using Computational Intelligence
… Extended X-ray Absorption Fine Structure (EXAFS) spectra carry information about the chemical structure of metal protein complexes. However, pre- dicting the structure of such complexes from EXAFS spectra is not a simple task. Currently methods such as Monte Carlo optimization or simulated …
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Structure of valinomycin-K+ complex and cryptate-k+ complex in solution by extended x-ray absorption fine structure
… is Extended X-ray Absorption Fine Structure (EXAFS). EXAFS is small oscillatory signals added on to the smooth x-ray absorption structure curve produced from the excitation of an inner electron out of its bound inner shell into a free electron state. The oscillations are produced from …
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Enhanced structural characterisation of supported catalysts
… characterisation methods, TEM, XRD and EXAFS were explored. Subsequent chapters focussed on improving the EXAFS analysis by (i) using molecular dynamics simulations as the inputs for structural fitting and (ii) by using a Cu UPD layer to cap the surface of the nanoparticles, thereby …
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A study of amorphous hydrogenated titanium carbide films: Structure, stability, and role of hydrogen doping
… using extended x-ray absorption fine structure (EXAFS), and extended energy-loss fine structure (EXELFS). The thesis presents a detailed description of the physical mechanism associated with EXAFS and EXELFS, a simple theoretical derivation of the EXAFS expression, a comparison of EXAFS and …
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X-Ray Absorption in Layered Crystals
Extended x-ray absorption fine struture (EXAFS) spectra have been obtained for a group of layered transitional-metal dichalcogenide crystals, including the nonstoichiometric compounds Ti(,1+x)Se(,2) and the alloys Zr(,x)Ti(,1-x)Se(,2). Fourier transform analysis of the EXAFS spectra has been …
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Structure of and Phase Transformations in Bulk Amorphous (GaSb)i_x(Ge2)I
… solids has been applied — the technique of EXAFS — under a variety of conditions: at low temperatures, under high pressures and at ambient conditions. Combined EXAFS and powder diffraction methods have been used to study the high pressure behavior of materials. The results revealed a complex …
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Developments of time-resolved XAFS spectroscopy techniques - applications in homogeneous catalysis
… In the standard scanning data acquisition mode, EXAFS spectra are obtained in timescales that vary from minutes to hours. An alternative data acquisition method, i.e. the energy dispersive (ED) mode, has been developed which allows short collection times and thus enables structural information on …
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Der Einfluss der Koordination von Spurenelementen in silikatischen und aluminosilikatischen Schmelzen auf Elementverteilungsprozesse in magmatischen Systemen
… die Untersuchung der Feinstruktur mittels der EXAFS-Spektroskopie (engl. Extended X-Ray Absorption Fine Structure) quantitative Informationen über die lokale Umgebung, während RIXS (engl. resonant inelastic X-ray scattering), sowie die daraus extrahierte hoch aufgelöste Nahkantenstruktur, XANES …
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Synthese und Charakterisierung von O,S-kernmodifizierten Porphyrinen und ihren Übergangsmetallkomplexen
… und Komplexe durch Röntgendiffraktometrie, EXAFS, NMR, UVVIS, Fluoreszenzspektroskopie, CV unf MS. Darstellung und Beschreibung dendritischer Heteroporphyrinmoleküle.
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A study of the structure of v-B2S3 and sodium thioborate glasses
… using extented x-ray absorption fine structure (EXAFS) to explore the structure of these glasses. Part of the analysis of the EXAFS data is a data reduction process which can influence the final outcome greatly. It is this data reduction process that is described here in order to guide new …
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Characterising catalyst preparation: from adsorbed precursor complex to catalyst particle
… this relationship using techniques such as EXAFS, XRD and TEM.<br/>A selection of Pt and Pd precursors has been deposited onto both Al2O3 and SiO2 supports and the resulting materials examined using these characterisation methods. Bimetallic combinations of these precursors have also been …
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XAS studies of metal speciation in hydrothermal fluids
… complex [NiCl₃(H₂O)]⁻, confirmed by both EXAFS analysis and XANES simulations. A similar coordination change of Mn(II) chloroaqua complexes has been quantitatively identified by analysis of both XANES and EXAFS data collected between 30 to 550 °C at 600 bar, with chlorinity ranging from …
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Structure and Ozone Decomposition Reactivity of Supported Manganese Oxide Catalysts
… and near edge x-ray absorption fine structure (EXAFS and NEXAFS) showed that the manganese oxide was highly dispersed on the surface of the supports. EXAFS spectra suggest that the manganese active centers on all of the surfaces were surrounded by five oxygen atoms. These metal centers were of a …
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Nanostruktur ionenbestrahlter Fe/Al- und Co/Cu-Grenzschichten
… von zahlreichen Analyseverfahren (RBS, CEMS, EXAFS, Röntgenverfahren, TEM, AES und magnetische Messungen), sowie Simulationsrechnungen auf Basis des ballistischen Mischens (TRIDYN) untersucht. Anschließend wird mit Hilfe von Ionenstrahlmischen und thermischem Anlassen die Grenzschichtstruktur …
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