977 research outputs found
New angles on D-branes
A low-energy background field solution is presented which describes several
D-membranes oriented at angles with respect to one another. The mass and charge
densities for this configuration are computed and found to saturate the BPS
bound, implying the preservation of one-quarter of the supersymmetries.
T-duality is exploited to construct new solutions with nontrivial angles from
the basic one.Comment: Latex, 12 pages, still no figures, references update
Towards the Classification of Non-Marginal Bound States of M-branes and Their Construction Rules
We present a systematic analysis of possible bound states of M-brane
solutions (including waves and monopoles) by using the solution generating
technique of reduction of M-brane to 10 dimensions, use of T-duality and then
lifting back to 11 dimensions. We summarize a list of bound states for one- and
two-charge cases including tilted brane solutions. Construction rules for these
non-marginal solutions are also discussed.Comment: Latex, 37 page
Local availability and long-range trade: the worked stone assemblage
Inter disciplinary study of major excavation assemblage from Norse settlement site in Orkney. Combines methodological and typological developments with scientific discussion
Two-electron bond-orbital model, 1
Harrison's one-electron bond-orbital model of tetrahedrally coordinated solids was generalized to a two-electron model, using an extension of the method of Falicov and Harris for treating the hydrogen molecule. The six eigenvalues and eigenstates of the two-electron anion-cation Hamiltonian entering this theory can be found exactly general. The two-electron formalism is shown to provide a useful basis for calculating both non-magnetic and magnetic properties of semiconductors in perturbation theory. As an example of the former, expressions for the electric susceptibility and the dielectric constant were calculated. As an example of the latter, new expressions for the nuclear exchanges and pseudo-dipolar coefficients were calculated. A simple theoretical relationship between the dielectric constant and the exchange coefficient was also found in the limit of no correlation. These expressions were quantitatively evaluated in the limit of no correlation for twenty semiconductors
Magnetometer with miniature transducer and automatic transducer scanning apparatus
Magnetometer is simple to operate and has fast response. Transducer is rugged and flat and can measure magnetic fields as close as 0.08 mm from any relatively flat surface. Magnetometer has active region of approximately 0.64 by 0.76 mm and is capable of good spatial resolution of magnetic fields as low as 0.02 Oe (1.6 A/m)
A magnetic field measurement technique using a miniature transducer
The development, fabrication, and application of a magnetometer are described. The magnetometer has a miniature transducer and is capable of automatic scanning. The magnetometer described here is capable of detecting static magnetic fields as low as 1.6 A/m and its transducer has an active area 0.64 mm by 0.76 mm. Thin and rugged, the transducer uses wire, 0.05 mm in diameter, which is plated with a magnetic film, enabling measurement of transverse magnetic fields as close as 0.08 mm from a surface. The magnetometer, which is simple to operate and has a fast response, uses an inexpensive clip-on milliammeter (commonly found in most laboratories) for driving and processing the electrical signals and readout. A specially designed transducer holding mechanism replaces the XY recorder ink pen; this mechanism provides the basis for an automatic scanning technique. The instrument has been applied to the measurements of magnetic fields arising from remanent magnetization in experimental plated-wire memory planes and regions of magnetic activity in geological rock specimens
Vapor phase growth of group 3, 4, and 5 compounds by HCl transport of elements
Technique has been devised for vapor-phase epitaxial growth of group 3, 4, and 5 binary, ternary, or quaternary compounds by HCl transport of the constituent elements or dopants. Technique uses all the constituents of the alloy system in their elemental form. Transport of these elements by an HCl + H2 carrier gas facilitates their transport as subchlorides
Hermitian D-brane solutions
A low-energy background field solution describing D-membrane configurations
is constructed which is distinguished by the appearance of a Hermitian metric
on the internal space. This metric is composed of a number of independent
harmonic functions on the transverse space. Thus this construction generalizes
the usual harmonic superposition rule. The BPS bound of these solutions is
shown to be saturated indicating that they are supersymmetric. By means of
T-duality, we construct more solutions of the IIA and IIB theories.Comment: 14 pages, Latex, no figure
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