17,678 research outputs found
Subcritical Superstrings
We introduce the Liouville mode into the Green-Schwarz superstring. Like
massive supersymmetry without central charges, there is no kappa symmetry.
However, the second-class constraints (and corresponding Wess-Zumino term)
remain, and can be solved by (twisted) chiral superspace in dimensions D=4 and
6. The matter conformal anomaly is c = 4-D < 1. It thus can be canceled for
physical dimensions by the usual Liouville methods, unlike the bosonic string
(for which the consistency condition is c = D <= 1).Comment: 9 pg., compressed postscript file (.ps.Z), other formats (.dvi, .ps,
.ps.Z, 8-bit .tex) available at
http://insti.physics.sunysb.edu/~siegel/preprints/ or at
ftp://max.physics.sunysb.edu/preprints/siege
A multiprocessor implementation of a contextual image processing algorithm
There are no author-identified significant results in this report
Green-Schwarz Formulation of Self-Dual Superstring
The self-dual superstring has been described previously in a
Neveu-Schwarz-Ramond formulation with local N=2 or 4 world-sheet supersymmetry.
We present a Green-Schwarz-type formulation, with manifest spacetime
supersymmetry.Comment: 11 pg., (uuencoded dvi file) ITP-SB-92-5
Confocal Ellipsoidal Reflector System for a Mechanically Scanned Active Terahertz Imager
We present the design of a reflector system that can rapidly scan and refocus a terahertz beam for high-resolution standoff imaging applications. The proposed optical system utilizes a confocal Gregorian geometry with a small mechanical rotating mirror and an axial displacement of the feed. For operation at submillimeter wavelengths and standoff ranges of many meters, the imaging targets are electrically very close to the antenna aperture. Therefore the main reflector surface must be an ellipse, instead of a parabola, in order to achieve the best imaging performance. Here we demonstrate how a simple design equivalence can be used to generalize the design of a Gregorian reflector system based on a paraboloidal main reflector to one with an ellipsoidal main reflector. The system parameters are determined by minimizing the optical path length error, and the results are validated with numerical simulations from the commercial antenna software package GRASP. The system is able to scan the beam over 0.5 m in cross-range at a 25 m standoff range with less than 1% increase of the half-power beam-width
REGULATORY EFFECTS OF POTASSIUM ON (Na + + K + )-ACTIVATED ADENOSINETRIPHOSPHATASE *
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73830/1/j.1749-6632.1974.tb19092.x.pd
Time-Delay Multiplexing of Two Beams in a Terahertz Imaging Radar
We demonstrate a time-delay multiplexing technique
that doubles the frame rate of a 660–690-GHz imaging radar
with minimal additional instrument complexity. This is done by
simultaneously projecting two offset, orthogonally polarized radar
beams generated and detected by a common source and receiver.
Beam splitting and polarization rotation is accomplished with a
custom designed waveguide hybrid coupler and twist. A relative
time lag of approximately 2 ns between the beams’ waveforms is
introduced using a quasi-optical delay line, followed by spatial
recombination using a selectively reflective wire grid. This delay is
much longer than the approximately 20-ps time-of-flight resolution
of the 30-GHz bandwidth radar, permitting the two beams’
reflected signals from a compact target to be easily distinguished
in digital post-processing of the single receiver channel
Heat-transfer and pressure drop correlations for hydrogen and nitrogen flowing through tungsten wire mesh at temperatures to 5200 deg r
Heat transfer and friction pressure drop for forced convection of hydrogen and nitrogen through electrically heated tungsten wire mes
A 4500 deg R /2500 deg K/ flowing-gas facility
High temperature flowing gas heater consisting of four stages for heating gase
Versatile liquid helium scintillation counter of large volume design
Design and performance of large liquid helium scintillation counter for meson experiment
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