Results 141 to 150 of about 58,697 (194)

Prismatic dislocation loops and concentric dislocation loops in HPHT-grown diamond single crystals

Materials Science and Engineering: A, 2003
Abstract As-grown diamond single crystals grown from Fe–Ni–C system under high temperature–high pressure were examined by transmission electron microscopy. There exist prismatic dislocation loops and concentric dislocation loops in the diamond, which are related to the nonequilibrium nature of the diamond synthesis process.
Long-Wei Yin, Mu-Sen Li, Zeng-Da Zou, Zhi-Guang Gong, Zhao-Yin Hao   +4 more
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Dislocation-loop-mediated smectic melting

Europhysics Letters (EPL), 2006
We report the direct observation, using freeze-fracture transmission electron microscopy, of topological melting in a lyotropic system in the vicinity of a smectic-cholesteric (N*) phase transition. The proliferation of dislocations leads to at least one, and possibly two intermediate phases, characterised by orientational ordering of the dislocation ...
P Moreau, L Navailles, J Giermanska-Kahn, O Mondain-Monval, F Nallet, D Roux   +5 more
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Dislocation loops in finite systems

Physical Review B, 1994
The distortions induced by dislocation loops are studied in finite systems. The influence of finite size, D, of the system, surface tension, and surface-bending elastic constant on the nematic-smectic (NA) phase transition is discussed. In thin freely suspended smectic liquid-crystal films the nematic-smectic transition temperature, ${\mathit{T}}_ ...
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Dislocation loops in irradiated iron

Philosophical Magazine, 1963
IT has been suggested many times that the hardening of iron and steel on irradiation may result from the interaction of glide dislocations with dispersed clusters of point defects. Two observations of such clusters using the technique of transmission electron microscopy have been reported in the literature1,2.
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Analysis of passing dislocation loops

Physica Status Solidi (a), 1974
The equilibrium configurations of passing dislocation loops on parallel slip planes have been determined as a function of applied stress using numerical techniques. It is shown that the stable equilibrium configurations of the loops correspond to minima in the energy surface determined by two loop radii, while the unstable equilibrium configurations ...
K. Sadananda, M. J. Marcinkowski
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Dechanneling due to dislocation loops

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1988
Abstract A theoretical description of axial dechanneling due to a special type of dislocation loops is presented. It is based on the discontinuous model with the displacement field calculated using the theory of Burgers. Using RBS data of Bentini et al. (1987) buried layers of dislocation loops in silicon are analysed.
Konrad Gärtner, Amaldo Uguzzoni
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Crack tip-dislocation loop interactions

Materials Science and Engineering: A, 1991
The elastic interaction between a circular dislocation loop and a crack in an infinite isotropic medium has been studied. This is believed to have a profound influence on the process of dislocation emission from the crack tip, especially in irratiated metals where loops are found in abundance.
A.S. Kirtikar, A.H. King
openaire   +1 more source

Circular edge dislocation loop

Czechoslovak Journal of Physics, 1960
A solution of the stress, deformation and deformation energy is given for an edge dislocation with its dislocation line having the shape of a circle in an unlimited isotropic medium. The possibility of using this solution in studying the dislocation loop in a crystal is discussed.
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Dislocation loops in quenched aluminium

Philosophical Magazine, 1958
Abstract Electron transmission micrographs of polycrystalline aluminium quenched from ∼ 600°c into iced brine show that the specimens contain many dislocation loops with diameters of the order of several hundred A. Some of the loops are hoxagonal in shape, and occur on (111) planes, and have a Burgers vector ½ [110] not in the plane of the loop.
P. B. Hirsch, J. Silcox, R. E. Smallman, K. H. Westmacott   +3 more
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Circular dislocation loops in bimaterials

Journal of Physics: Condensed Matter, 1991
The solution of the elastic field in bimaterials due to a circular dislocation loop of arbitrary orientation within one of the materials is presented. The bimaterial is idealized as two semi-infinite isotropic elastic solids either perfectly bonded together or in frictionless contact with each other at the planar interface.
H Y Yu, S C Sanday
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