The charge carried by moving dislocations was measured in NaCl single crystals doped with divalent cation impurities, and the connection between the charge and the concentration of the free cation vacancies of the crystal was investigated. According to the experimental results the dislocations carry negative charge and the magnitude of the charge changes proportionally to the concentration of t...

We study the interaction between vacancies in a two-dimensional van der Waals crystal by molecular dynamics simulation. We find that the vacancy–vacancy interaction is attractive at short distances, but its binding energy is not enough to keep the pair bounded at the melting region where the vacancies are more likely to be created. c © 2007 Elsevier Ltd. All rights reserved. PACS: 61.72.-y; 61....

A high-speed method for elliptical object location is proposed. Through the use of the geometric symmetry, it first locates the centers of elliptical objects and classifies the boundary points. Then, each point possible on an elliptical object boundary is used to obtain the remaining three parameters of the elliptical object. Since each boundary point is at most transformed to one point on the ...

A new elliptical invisible cloak is proposed using a coordinate transformation in the elliptical-cylindrical coordinate system, which crushes the cloaked object to a line segment instead of a point. The elliptical cloak is reduced to a nearly-circular cloak if the elliptical focus becomes very small. The advantage of the proposed invisible cloak is that none of the parameters is singular and th...

The use of elliptical chainrings (also called chainwheels or sprockets) has gained considerable interest in the amateur and professional cycling community. Nevertheless, we are unaware of any scientific studies that have examined the performance benefits of using elliptical chainrings during an actual performance trial. Therefore, this study examined the influence of elliptical chainring use on...

Elliptical galaxies were once thought to be similar in their structure and dynamics to rotationally flattened bodies like stars. The discovery that elliptical galaxies rotate much more slowly than a fluid body with the same shape has led to a qualitative change in our understanding of the dynamics of these systems. It is now believed that elliptical galaxies are fully triaxial in shape. Self-co...

We analyse the effect of a low-frequency elliptically polarized electric field on an excited hydrogen atom using classical dynamics. It is shown that at particular frequencies the ionization probability is a non-monotonic function of the field strength and that at these frequencies the classical ionization probabilities agree well with those of experiment. We show that this unusual behaviour is...

We present evidence for non-Gaussian velocity fields within the cores of luminous elliptical galaxies. This evidence is based on high signal-to-noise ratio, medium-resolution spectroscopy of the cores of early-type members of the Virgo and Coma Clusters obtained with the Wisconsin-Indiana-Yale-NOAO 3.5 m telescope. The Virgo data were acquired using an integral-field unit (DensePak), which allo...

We study the influence of particle shape on the shear band formation in quasistatic granular media in biaxial compression test using two-dimensional Distinct Element Method (DEM). Elliptical-shaped particles are used to study the influence of particle shape. We also report an experimental verification to check the ability of DEM to model elliptical particles created by the clustering technique....