منابع مشابه
Pinwheel patterns and powder diffraction
Pinwheel patterns and their higher dimensional generalisations display continuous circular or spherical symmetries in spite of being perfectly ordered. The same symmetries show up in the corresponding diffraction images. Interestingly, they also arise from amorphous systems, and also from regular crystals when investigated by powder diffraction. We present first steps and results towards a gene...
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Diffraction images with continuous rotation symmetry arise from amorphous systems, but also from regular crystals when investigated by powder diffraction. On the theoretical side, pinwheel patterns and their higher dimensional generalisations display such symmetries as well, in spite of being perfectly ordered. We present first steps and results towards a general frame to investigate such syste...
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We present a scheme to identify quasicrystals based on powder diffraction data and to provide a standardized indexing. We apply our scheme to a large catalog of powder diffraction patterns, including natural minerals, to look for new quasicrystals. Based on our tests, we have found promising candidates worthy of further exploration.
متن کاملSimulation of powder diffraction patterns of modified ordered mesoporous materials
Powder diffraction patterns of ordered mesoporous materials are simulated with a newly developed program, which allows investigation of the influence of any desired matter distribution in the unit cell on the diffraction pattern. The simulation process can be subdivided into two major steps. First, a unit cell is generated from SiO2 and, optionally, other building units. A weighted random place...
متن کاملVII. Workshop Powder Diffraction Structure Determination and Refinement from Powder Diffraction Data
New techniques have been integrated into EXPO (Altomare et al., 1999), a package devoted to extracting the integrated intensities from an indexed powder diffraction pattern and to solving crystal structures via Direct Methods. An efficient peak-search algorithm and an improved version of the program TREOR90 (Werner et al., 1985) have been introduced in order to offer new tools for a more powerf...
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ژورنال
عنوان ژورنال: Philosophical Magazine
سال: 2007
ISSN: 1478-6435,1478-6443
DOI: 10.1080/14786430601057953