This paper deals with the passage from discrete to continuous in modeling the static elastic properties, in the setting of anti-planar linear elasticity, of vertical screw dislocations in a cylindrical crystal. We study, in the framework of Γ-convergence, the asymptotic behavior of the elastic stored energy induced by dislocations as the atomic scale ε tends to zero, in the regime of dilute dis...

Screw dislocations play an important role in materials' mechanical, electrical and optical properties. However, imaging the atomic displacements in screw dislocations remains challenging. Although advanced electron microscopy techniques have allowed atomic-scale characterization of edge dislocations from the conventional end-on view, for screw dislocations, the atoms are predominantly displaced...

Dislocations of the cervicothoracic junction are frequently missed. Experience of this rare injury over 27 years at the Spinal Injuries Unit in Sheffield confirms that nearly two-thirds were not properly diagnosed on admission. Only two of the 14 dislocations studied were reduced by conservative methods and these were both associated with fractures of the posterior bony elements. Open reduction...

Asymmetric bilateral dislocations of the hips are rare injuries. Among the small number of reports in the literature, most have attributed the cause to high-velocity motor crashes. These dislocations are often seen to be associated with fractures of the proximal femur or the acetabulum. We present a case of a 45-year-old man with bilateral asymmetric dislocation of hips which were purely ligame...

The influence of dislocations on nitrogen±oxygen (N±O) complexes in nitrogen-doped Czochralski (NCZ) silicon was investigated. It was found that N±O complexes were generated during annealing at 650 C for 10 min. In the early stage of annealing the amount of the N±O complexes in NCZ silicon with dislocations was almost the same as in dislocation-free NCZ silicon. However, the N±O complexes in NC...

The deformation behavior of nanoparticles continues to be an exciting area for materials research. Typically, nanoparticles show a conspicuous lack of dislocations, even after significant deformation. Therefore, it has been suggested that dislocations cannot exist or/do not play a role on the deformation of nanoparticles. In situ TEM nanoindentation is a critical tool for addressing this issue ...

The motion of dislocations in irradiated materials has unique features that are not seen in unirradiated materials undergoing plastic deformation. In the present work, we show dislocation dynamics studies that reveal the single and collective aspects of dislocation motion in materials under displacement cascade damage. First, we investigate the dynamics of dislocation interaction with irradiati...

Conductive atomic force microscopy ~C-AFM! and surface photovoltage ~SPV! microscopy were used to investigate local electronic structure in p-type GaN. C-AFM imaging revealed locally reduced forwardand reverse-bias conductivity near threading dislocations. In addition, regions near threading dislocations demonstrated significantly enhanced surface photovoltage response when compared to regions ...