In this paper we analyse the behaviour of a pile-up of vertically periodic walls of edge dislocations at an obstacle, represented by a locked dislocation wall. Starting from a continuum non-local energy Ec modelling the interactions—at a typical length scale of 1/c— of the walls subjected to a constant shear stress, we derive a first-order approximation of the energy by Γ-convergence in the lim...

We study the dynamics of focal conic domain (FCD) formation in a thermotropic smectic phase under shear stress. It is known that increasing the shear stress induces a non-equilibrium phase transition from a smectic phase with FCDs (SmAI) to another smectic phase (SmAII) in which the layers are oriented. By quenching the shear stress from the SmAII phase to the SmAI phase, we find three characte...

We present models of localized plastic deformation inside Persistent Slip Band channels. First, we investigate the interaction between screw dislocations as they pass one another inside channel walls in copper. The model shows the mechanisms of dislocation bowing, dipole formation and binding, and finally dipole destruction as screw dislocations pass one another. The mechanism of (dipole passin...

Strained oxide thin films are of interest for accelerating oxide ion conduction in electrochemical devices. Although the effect of elastic strain has been uncovered theoretically, the effect of dislocations on the diffusion kinetics in such strained oxides is yet unclear. Here we investigate a 1/2<110>{100} edge dislocation by performing atomistic simulations in 4-12% doped CeO2 as a model fast...

The structural, electrical, and optical properties of GaN grown on 6HSiC(0001) substrates by molecular beam epitaxy are studied. Suitable substrate preparation and growth conditions are found to greatly improve the structural quality of the films. Threading dislocation densities of about 1 × 10 cm for edge dislocations and < 1 × 10 cm for screw dislocations are achieved in GaN films of 0.8 μm t...

Based on an orientation-dependent dislocation line energy, a solution to the acoustic nonlinearity parameter is obtained for pure and mixed dislocations in anisotropic crystals. The solution is validated by comparison with molecular dynamic simulations. Parametric studies using this new solution show that (i) elastic anisotropy can significantly change the nonlinear behavior of dislocations inc...

We analyse a continuous magnon spectrum which is excited in FMR in a ferromagnetic sample with dislocations. Calculations are presented for the moments of the uniform mode. Numerical comparisons of the moment method with literature data and the Born approximation are given for the broadening of the resonance line. In monocrystalline ferromagnets, the dislocations have the remarkable effect on r...

condylar dislocation is not an uncommon condition and occurs when the condyles are displaced anterior to the articular eminence and are unable to reduce back into the glenoid fossa. long-standing dislocations are difficult to treat with the conservative methods and usually need surgical intervention. in this paper, a long-standing dislocation treated by bilateral extra-oral ramus osteotomy is d...