120,751 research outputs found
Electron Band Structure in a Two Dimensional Periodic Magnetic Field
In this paper we study the energy spectrum of a two dimensional electron gas
(2DEG) in a two dimensional periodic magnetic field. Both a square magnetic
lattice and a triangular one are considered. We consider the general case where
the magnetic field in a cell can be of any shape. A general feature of the band
structure is bandwidth oscillation as a function of the Landau index. A
triangular magnetic lattice on a 2DEG can be realized by the vortex lattice of
a superconductor film coated on top of a heterojunction. Our calculation
indicates a way of relating the energy spectrum of the 2DEG to the vortex
structure. We have also derived conditions under which the effects of a weak
magnetic modulation, periodic or not, may be reproduced by an electric
potential modulation, and vice versa.Comment: 16 pages in TeX and 5 uuencoded figure
Wind tunnel buffet load measuring technique
Indirect force measurement technique estimates unsteady forces acting on elastic model during wind tunnel tests. Measurement of forces is practically insensitive to errors in aeroelastic scaling between model and full-scale structure, simplifying design, fabrication and dynamic calibration
Numerical calculation of the transonic potential flow past a cranked wing
The widely transonic swept-wing code, FL022, was found to have an error in the transformed flow equation in the computational domain. The revised version of the code correctly accounted for the non-straight leading edge geometry and its effect on the pressure distribution
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