It is also recognized that a moving screw dislocation
, which cuts through another crew dislocation, acquires a jog or discontinuity which produces a row of vacancies or interstitials as the moving dislocation continues its advance.
mu]] = 0 and a screw dislocation
which can be right-handed for which [b.
Suppose that a piezoelectric material is transversely isotropic and containing a charged screw dislocation
around a finite crack of length 2a as shown in Fig.
A prime example is the presence of a screw dislocation
in a crystal (Fig.
Few centers of screw dislocation
are evident and the wall surface resembles a foliated fabric ("pseudofoliated").
As shown in , the screw dislocation
Burgers vector is equal to the wavelength of the screw dislocation
16) elaborated on an earlier proposal of Bassett and Hodge (17) that linked lamellar twist with repetition of isochiral screw dislocations
in growing lamellae.
The results obtained by PLM for micropipes and elementary screw dislocations
are comparable with the topography provided by back-reflection synchrotron white beam X-ray topography (SWBXT); while the results for grain boundaries and stress striations are comparable with that provided by the transmission mode X-ray topography.
For the present data, assuming that only screw dislocations
(Burgers vector 1/2<110>) are present, it holds that [C.
Four months ago, when two independent research groups reported the discovery of billions of spiral defects in superconducting thin films, both teams suggested that putting these defects, called screw dislocations
, into wires might boost their current-carrying capacity, or critical current density, to that of thin films (SN: 4/6/91, p.
Levine of Washington State University, has succeeded in deriving the effect of screw dislocations
on Bragg x-ray scattering (25).
The yield behavior of these materials was successfully analyzed in relation to the average crystal thickness, on the basis of a model assuming crystal slip through thermally activated nucleation of screw dislocations