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Glide Plane (glide + plane)
Selected AbstractsThree-dimensional visualization of the inner structure of single crystals by step-scanning white X-ray section topographyJOURNAL OF SYNCHROTRON RADIATION, Issue 6 2006Taihei Mukaide Visualization of the three-dimensional distribution of the crystal defects of large single crystals of calcium fluoride has been demonstrated by white X-ray section topography using sheet-like X-rays (BL28B2 at SPring-8). An image of the three-dimensional distribution of the crystal defects was reconstructed by stacking section topographs, which expressed the images of cross sections of the sample. The section topographs were recorded using a CMOS flat-panel imager or a CCD detector combined with scintillator (Gd2O2S:Tb) and relay lens system. The section topographs were measured by repeating cycles of exposure and sample translation along the direction perpendicular to the top face of the sample. Using high-brilliance and high-energy white X-rays (,60,keV) efficiently, visualization of the three-dimensional structure of subgrains of a sample of up to 60,mm in diameter was achieved. Furthermore, the three-dimensional distribution of the glide plane in the crystal was visualized by reconstructing the linear contrast of the glide plane. [source] HRTEM of dislocation cores and thin-foil effects in metals and intermetallic compoundsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 5 2006M.J. Mills Abstract Examples of the observation and analysis of dislocation cores and dislocation fine structure in metals and intermetallics using high resolution transmission electron microscopy are discussed. Specific examples include the 60° dislocations in aluminum, a,011, edge dislocations in NiAl, and screw dislocations in Ni3Al. The effect of the thin TEM foils on the structure and imaging of these dislocations is discussed in light of embedded atom method calculations for several configurations and coupled with image simulations. Some generalizations based on these calculations are discussed. These analyses enables determination of the spreading or decomposition of the edge component of the cores, both in and out of the glide plane, which can have significant implications for the modeling of macroscopic behavior. Microsc. Res. Tech. 69:317,329, 2006. © 2006 Wiley-Liss, Inc. [source] Gliding dislocations in Bi2Te3 materialsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2009N. Peranio Abstract In Bi2Te3, dislocations were found with an uniquely high mobility at room temperature. The gliding dislocations were analysed and their effect on the thermoelectric properties is discussed. The glide of dislocations was induced by heating with a focused electron beam at 120 keV, external stresses were not applied. The dislocations were bowed out in the glide direction and were only pinned at the surface of the samples. Stereomicroscopy combined with image simulations yielded basal plane dislocations with a density of 109 cm,2 and Burgers vectors of type ,110,. Video sequences showing the glide of single dislocations and groups of dislocations were recorded. Isolated dislocations showed a high mobility in ±,110, direction at a velocity of 10,100 nm s,1. Dislocation dipoles were pinned and did not glide. Dislocations equidistantly arranged within the same glide plane showed a collective movement. Dislocations piled up in different glide planes were fixed and acted as barriers for gliding dislocations. The motion of dislocations was attributed to residual shear stresses of about 10 MPa, and their glide directions depended on the sign of the Burgers vector. Attractive and repulsive forces of dislocations directly visualise the forces due to the elastic strain fields of other dislocations. The relevance of phonon scattering on dislocations in Bi2Te3, particularly due to their high mobility and density, was confirmed by two inspections: (i) Dislocations decrease the lattice thermal conductivity due to phonon scattering on the elastic strain field. The phonon mean free path was estimated to about 800 µm at 3 K and agreed with published data. (ii) The dislocation resonance theory of Granato and Lücke predicts an interaction between phonons and dislocations acting as oscillating strings. The attenuation of ultrasound was estimated and was compared with published data. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] catena -Poly[[(trifluoromethanesulfonato-,O)silver(I)]-,-di-2-pyridylamine-,2N2:N2,], a chain polymer with short Ag,C contactsACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2006Peter G. Jones The title compound, [Ag(CF3O3S)(C10H9N3)]n, is a chain polymer in which neighbouring monomeric units are related by a glide plane. The silver centre is four-coordinate; the donor atoms are one trifluoromethanesulfonate O atom and one pyridine N atom from each of two symmetry-related dipyridylamines, and an additional and unexpected Ag,C contact [2.6464,(16),Å] is observed to a pyridine C atom. The chains are reinforced by one classical N,H,O and two `weak' C,H,O hydrogen bonds. [source] (2RS)-5,6:7,8-Dibenzobicyclo[2.2.2]octan-2-olACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2003Kenneth W. Muir The racemic form of the title secondary monoalcohol, C16H14O, forms crystals in which the molecules are linked into chains by hydrogen bonding. The chain architecture is unusual; adjacent molecules are related pseudosymmetrically, by either a pseudo-diad or a pseudo-glide plane, while alternate molecules are related exactly by a crystallographic glide plane. [source] Gliding dislocations in Bi2Te3 materialsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2009N. Peranio Abstract In Bi2Te3, dislocations were found with an uniquely high mobility at room temperature. The gliding dislocations were analysed and their effect on the thermoelectric properties is discussed. The glide of dislocations was induced by heating with a focused electron beam at 120 keV, external stresses were not applied. The dislocations were bowed out in the glide direction and were only pinned at the surface of the samples. Stereomicroscopy combined with image simulations yielded basal plane dislocations with a density of 109 cm,2 and Burgers vectors of type ,110,. Video sequences showing the glide of single dislocations and groups of dislocations were recorded. Isolated dislocations showed a high mobility in ±,110, direction at a velocity of 10,100 nm s,1. Dislocation dipoles were pinned and did not glide. Dislocations equidistantly arranged within the same glide plane showed a collective movement. Dislocations piled up in different glide planes were fixed and acted as barriers for gliding dislocations. The motion of dislocations was attributed to residual shear stresses of about 10 MPa, and their glide directions depended on the sign of the Burgers vector. Attractive and repulsive forces of dislocations directly visualise the forces due to the elastic strain fields of other dislocations. The relevance of phonon scattering on dislocations in Bi2Te3, particularly due to their high mobility and density, was confirmed by two inspections: (i) Dislocations decrease the lattice thermal conductivity due to phonon scattering on the elastic strain field. The phonon mean free path was estimated to about 800 µm at 3 K and agreed with published data. (ii) The dislocation resonance theory of Granato and Lücke predicts an interaction between phonons and dislocations acting as oscillating strings. The attenuation of ultrasound was estimated and was compared with published data. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The role of the tangent bundle for symmetry operations and modulated structuresACTA CRYSTALLOGRAPHICA SECTION A, Issue 3 2010Philippe Kocian An equivalence relation on the tangent bundle of a manifold is defined in order to extend a structure (modulated or not) onto it. This extension affords a representation of a structure in any tangent space and that in another tangent space can easily be derived. Euclidean symmetry operations associated with the tangent bundle are generalized and their usefulness for the determination of the intrinsic translation part in helicoidal axes and glide planes is illustrated. Finally, a novel representation of space groups is shown to be independent of any origin point. [source] | ||||||||||