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Diffraction Investigations (diffraction + investigation)

Distribution by Scientific Domains
Chemistry66%
Physics and Astronomy22%

Kinds of Diffraction Investigations

  • x-ray diffraction investigation
    		•

    Selected Abstracts

    In Situ Time-Resolved Neutron Diffraction Investigation during Oxygen Exchange in Layered Cobaltite Cathode Materials,

    ANGEWANDTE CHEMIE, Issue 45 2009
    Lorenzo Malavasi Dr.
    Man achte auf den Sauerstoff: Mit dem im Titel genannten Verfahren können die beim Sauerstoffaustausch in einem Material auftretenden Strukturänderungen untersucht werden (siehe Diagramm für die Zunahme des Sauerstoffgehalts, wenn der Gasfluss von Ar auf O2 umgestellt wird). Die Methode wird an einem schichtförmigen Cobaltit demonstriert, einem vielversprechenden Kathodenmaterial für Brennstoffzellen. [source]

    ChemInform Abstract: Tetragonal to Orthorhombic Phase Transition in SmFeAsO: A Synchrotron Powder Diffraction Investigation.

    CHEMINFORM, Issue 33 2009
    A. Martinelli
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    X-ray Diffraction Investigations of Microstructure of Calcium Hydroxide Crystallites in the Interfacial Transition Zone of Concrete

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2003
    Valeri S. Harutyunyan
    This work presents theoretical and experimental X-ray diffractometry investigations of the morphology and deformation state of calcium hydroxide (Ca(OH)2, CH) crystallites in the interfacial transition zone of concrete. Based on the developed theoretical approach, the distributions of CH crystallites and their coherent domains over strains and sizes are reconstructed. The average amounts of planar defects, cracks, and possible stacking faults within a CH crystallite are estimated. A comparative analysis is conducted for the morphology of CH texture depending on the type of aggregate particles (granite and smoky quartz) used. [source]

    Neutron Diffraction Investigations and Magnetic Properties of LnNi3.5Al1.5 Compounds and Their Hydrides (Deuterides).

    CHEMINFORM, Issue 10 2006
    M. Bououdina
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

    Single-crystal neutron diffraction investigation on crystals belonging to the langasite family: a comparative study

    ACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2010
    R. Chitra
    Crystals of the langasite family are of interest as they are piezoelectric in different devices. The properties of these classes of crystals can be modified within certain limits by isomorphous substitution. Single-crystal neutron diffraction studies were carried out for LGT (La3Ga5.5Ta0.5O14), LGST (La3Ga5.25Ta0.25Si0.5O14) and LGZrT (La3Ga5.25Ta0.25Zr0.5O14) as the neutron study gives a better average picture of the crystal properties over a macroscopic region of the grown crystal. The effect of small substitutions at various sites on the piezoelectric properties of the crystal was studied. [source]

    Single-crystal X-ray and neutron powder diffraction investigation of the phase transition in tetrachlorobenzene

    ACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2006
    Charlotte K. Broder
    The polymorphic phase transition of 1,2,4,5-tetrachlorobenzene (TCB) has been investigated using neutron powder diffraction and single-crystal X-ray diffraction. The diffraction experiments show a reversible phase change that occurs as a function of temperature with no apparent loss of sample quality on transition between the two phases. Neutron powder diffraction gives detailed information on the molecular structural changes and lattice parameters from 2,K to room temperature. The structure of the low-temperature form has been elucidated for the first time using single-crystal X-ray diffraction. Comparison of the , and , structures show that they are both based on the same sheet motif, with the differences between the two being very subtle, except in terms of crystal symmetry. Detailed analysis of the structures revealed the changes required for inter-conversion. A computational polymorph search showed that these two sheet structures are more thermodynamically stable than alternative herringbone-type structures. [source]

    Morphological, structural and optical study of quasi-1D SnO2 nanowires and nanobelts

    CRYSTAL RESEARCH AND TECHNOLOGY, Issue 10-11 2005
    D. Calestani
    Abstract 0.1,0.3 mm thick entanglements of quasi-one-dimensional semiconducting Tin dioxide nanocrystals, in form of nanowires and nanobelts, are successfully grown by low cost Chemical Vapour Deposition directly on large area (100 mm2) Al2O3, SiO2 and Si substrates. Their lateral size ranges from 50 to 700 nm and their length can achieve several hundreds of micrometers. Transmission Electron Microscopy reveals either the nanowires and the nanobelts grow in the tetragonal Rutile structure. Diffraction contrast analyses and selected area diffraction investigations show the nanowires are single crystals without defects while the nanobelts sometimes present twins inside. An almost cylindrical shape and an average diameter of about 30,50 nm for the smallest nanowires is reported. X-ray diffraction investigations exclude the presence of spurious phases. A broad band structured in two emissions peaked at about 450 nm and 560 nm is revealed by large area Cathotoluminescence, while single nanocrystal spectroscopy shows that the reduction of the lateral dimension of the nanobelts from 1000 nm to 50 nm blue-shifts the main emission band at 560 nm of about 40 nm (at room temperature). These preliminary results suggest a possible role of oxygen vacancies and of the surface/volume ratio on the origin and the blue shift of Cathodoluminescence spectra. The near band edge emission, typical of bulk tin dioxide (,320 nm), is not found in nanobelts narrower than 1000 nm. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    In situ X-ray diffraction analysis of iron ore sinter phases

    JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3 2004
    Nicola V. Y. Scarlett
    Owing to the depletion of world lump iron ore stocks, pre-treated agglomerates of fine ores are making up a growing proportion of blast-furnace feedstock (,80%). These agglomerations, or `sinters', are generally composed of iron oxides, ferrites (most of which are silicoferrites of calcium and aluminium, SFCAs), glasses and dicalcium silicates (C2S). SFCA is the most important bonding phase in iron ore sinter, and its composition, structural type and texture greatly affect its physical properties. Despite its prevalence and importance, the mechanism of SFCA formation is not fully understood. In situ powder X-ray diffraction investigations have been conducted into the formation of SFCA, allowing the study of the mechanism of its formation and the observation of intermediate phases with respect to time and temperature. Studies have been carried out to investigate the effects of changing the substitution levels of aluminium for iron. The use of the Rietveld method for phase quantification gives an indication of the order and comparative rates of phase formation throughout the experiments. [source]

    A comprehensive investigation of the structural properties of ferroelectric PbZr0.2Ti0.8O3 thin films grown by PLD

    PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2009
    David Walker
    Abstract X-Ray diffraction investigations were made of high-quality epitaxial thin films of the ferroelectric material lead zirconate titanate, PbZr0.2Ti0.8O3 (PZT), grown by pulsed laser deposition (PLD). Layers from 7 to 200,nm in thickness were studied, deposited on a 30,nm SrRuO3 (SRO) electrode on a [001] oriented SrTiO3 (STO) substrate. The out-of-plane lattice parameters of the PZT films were measured by high-resolution X-ray diffraction using CuK,1 radiation. A significant enhancement of the c lattice parameter with film thickness was observed, the maximum value of 4.25,Å reached in the 30,50,nm thick films. For film thicknesses greater than 100,nm, the c lattice parameter is relaxed, towards the bulk value of 4.13,Å at this composition. The in-plane lattice parameters were studied by Grazing incidence X-ray scattering (GIXS), using 15,keV synchrotron radiation at I16, Diamond. The a lattice parameter of domains with [001] oriented normal to the sample surface was effectively lattice matched to the SRO layer in the 7,nm ultra-thin film, but relaxed compared to the SRO in thicker films. The tetragonality of the [001] oriented domains decreases with increasing film thickness, approaching the bulk value of 1.05 in the thickest films. Evidence for the presence of [100] oriented a -domains was found in PZT films as thin as 30,nm, the proportion of which increased with increasing film thickness, suggesting they grow in order to relieve stresses that would prevent the epitaxial growth of thicker PZT films. The a -domains in the thicker films were found to be located nearer to the PZT/SRO interface than to the top surface of the PZT. [source]