In 4H-silicon carbide crystals, basal plane slip is the predominant deformation mechanism. However, prismatic often observed in single crystals grown by physical vapor transport method as diameter expands to 6 inches or larger. Thermal modeling has shown that occurrence of attributed increased radial thermal gradients. While X-ray topography can be used characterize presence and extent slip, fe...

The pathways by which dislocations, line defects within the lattice structure, overcome microstructural obstacles represent a key aspect in understanding the main mechanisms that control mechanical properties of ductile crystalline materials. While edge dislocations were believed to change their glide plane only by a slow, non-conservative, thermally activated motion, we suggest the existence o...

The strain of GaN layers grown by Metal Organic Chemical Vapor Deposition (MOCVD) on three vicinal 4H-SiC substrates (0, 3.4 and 8 offcut from [0001] towards [11-20] axis) is investigated by X-ray Diffraction (XRD), Raman Scattering and Cathodoluminescence (CL). The strain relaxation mechanisms are analyzed for each miscut angle. At a microscopic scale, the GaN layer grown on on-axis substrate ...

Chronic unreduced anterior dislocations of the shoulder are rare. Arterial and neurological complications in chronic glenohumeral dislocations are even less frequent. We report three cases of old anterior shoulder dislocations. Open reduction is indicated for most chronic shoulder dislocations. Arterial lesions require urgent intervention with reconstruction. Conservative treatment is advised f...

Strained thin films often contain ordered networks of misfit dislocations which can determine their chemical and mechanical properties. We consider the reaction of sulfur with two-monolayer films of Cu on Ru(0001). These films contain a network of parallel partial dislocations, separating regions of fcc and hcp stacking, with threading edge dislocations where partial dislocations meet. Sulfur r...