نتایج جستجو برای: dislocation

تعداد نتایج: 28502  

2016
Berhe Gebreslassie

The causes of hip dislocation in children are fall down accidents in 50% of cases, road traffic accidents in 30%, and sports and recreational activities in 15% [4]. Even though this is one of the emergency condition in orthopedics, patients present in developing countries late to a health facility. The definition of old or late dislocation of the hip was not clearly mentioned on literatures but...

2009
G. P. Purja Pun Y. Mishin

Self-diffusion along screw and edge dislocations in Al is studied by molecular dynamics simulations. Three types of simulations are performed: with pre-existing vacancies in the dislocation core, with pre-existing interstitials, and without any pre-existing defects (intrinsic diffusion). We find that diffusion along the screw dislocation is dominated by the intrinsic mechanism, whereas diffusio...

2001
Markus Lazar

We consider a static theory of dislocations with moment stress in an anisotropic or isotropic elastoplastical material as a T (3)-gauge theory. We obtain Yang-Mills type field equations which express the force and the moment equilibrium. Additionally, we discuss several constitutive laws between the dislocation density and the moment stress. For a straight screw dislocation, we find the stress ...

2015
Zhiyang Lin Marisol Koslowski

Self-organized criticality (SOC) is widely observed in systems ranging from creep deformation of single crystal ice to the movement of glacier. -The behavior of these SOC systems follows a power law distribution, which is timeand space-scale invariant. Previous phase field simulation of single crystal nickel has shown that plastic flow is characterized by intermittent dislocation avalanches, wh...

2000
Leonid Burakovsky Dean L. Preston Richard R. Silbar

We present a theory of the melting of elemental solids as a dislocation-mediated phase transition. We model dislocations near melt as non-interacting closed strings on a lattice. In this framework we derive simple expressions for the melting temperature and latent heat of fusion that depend on the dislocation density at melt. We use experimental data for more than half the elements in the Perio...

2005
V. A. Lubarda

If there is an equilibrium arrangement of a given collection of dislocations, each having a fixed size and shape, in an externally loaded or unloaded elastic body, the corresponding potential energy will be stationary with respect to infinitesimal perturbations of the dislocation positions. This leads to the dislocation equilibrium conditions: the Peach– Koehler forces along the dislocation lin...

Journal: :Physical review letters 2008
J Y Huang F Ding B I Yakobson

Dislocation dynamics dictate the mechanical behavior of materials. Dislocations in periodic crystalline materials have been well documented. On the contrary, dislocations in cylindrical carbon nanotubes, particularly in multiwalled carbon nanotubes (MWCNTs), remain almost unexplored. Here we report that a room temperature 1/2<0001> sessile dislocation in a MWCNT becomes highly mobile, as charac...

2002
Markus Lazar

A (linear) nonsingular solution for the edge dislocation in the translational gauge theory of defects is presented. The stress function method is used and a modified stress function is obtained. All field quantities are globally defined and the solution agrees with the classical solution for the edge dislocation in the far field. The components of the stress, strain, distortion and displacement...

Journal: :The Journal of bone and joint surgery. British volume 1982
G C Bennet M Rang D P Roye H Aprin

Almost one child in twenty with trisomy 21 will develop spontaneous dislocation of the hip between learning to walk and the age of 10 years. After the age of two years spontaneous habitual dislocation may occur. If left untreated, acute dislocation, subluxation and fixed dislocation follow in sequence. The natural history of the condition is described and the clinical and radiological features ...

2013
Akio Ishii Ju Li Shigenobu Ogata

Dislocation pipe diffusion seems to be a well-established phenomenon. Here we demonstrate an unexpected effect, that the migration of interstitials such as carbon in iron may be accelerated not in the dislocation line direction ξ, but in a conjugate diffusion direction. This accelerated random walk arises from a simple crystallographic channeling effect. c is a function of the Burgers vector b,...

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