92,119 research outputs found
Dynamical properties of a two-dimensional electron gas in a magnetic field within the composite fermion model
We investigate the response of a two-dimensional electron gas, in the
fractional quantum Hall regime, to the sudden appearance of a localised charged
probe using the Chern-Simons theory of composite fermions. The dynamic
structure factor of the electron gas is found to have a major influence on the
spectral function of the probe. In particular, there is an orthogonality
catastrophe when the filling factor is an even-denominator filling fraction due
to the compressibility of the state, but there is no catastrophe at
odd-denominator filling factors because these states have a gap to excitations.
The catastrophe is found to be more severe for composite fermions in zero
effective magnetic field than it is for electrons in zero real magnetic field.
Oscillations in the spectral function, arising when the composite fermions are
at integer filling, have a period equal to the composite fermion cyclotron
energy. We propose a tunneling experiment which directly measures the spectral
function from which one could determine the composite fermion effective mass.Comment: 15 pages of REVTEX. Uses multicol package. Twoside option is default.
There are 29 figures in GIF format to save spac
Integrated payload and mission planning, phase 3. Volume 2: Logic/Methodology for preliminary grouping of spacelab and mixed cargo payloads
The logic and methodology for a preliminary grouping of Spacelab and mixed-cargo payloads is proposed in a form that can be readily coded into a computer program by NASA. The logic developed for this preliminary cargo grouping analysis is summarized. Principal input data include the NASA Payload Model, payload descriptive data, Orbiter and Spacelab capabilities, and NASA guidelines and constraints. The first step in the process is a launch interval selection in which the time interval for payload grouping is identified. Logic flow steps are then taken to group payloads and define flight configurations based on criteria that includes dedication, volume, area, orbital parameters, pointing, g-level, mass, center of gravity, energy, power, and crew time
Chebychev trajectory optimization program /CHEBYTOP 2/ Final report
Computer program for electric propelled spacecraft interplanetary, flyby, and rendezvous trajectory optimization based on Chebyshev approximation and polynomial representation
Development of an aerodyanmic theory capable of predicting surface loads on slender wings with vortex flow
The Boeing Commercial Airplane Company developed an inviscid three-dimensional lifting surface method that shows promise in being able to accurately predict loads, subsonic and supersonic, on wings with leading-edge separation and reattachment
Artwork Interactive Design System (AIDS) program description
An artwork interactive design system is described which provides the microelectronic circuit designer/engineer a tool to perform circuit design, automatic layout modification, standard cell design, and artwork verification at a graphics computer terminal using a graphics tablet at the designer/computer interface
Advanced surface paneling method for subsonic and supersonic flow
Numerical results illustrating the capabilities of an advanced aerodynamic surface paneling method are presented. The method is applicable to both subsonic and supersonic flow, as represented by linearized potential flow theory. The method is based on linearly varying sources and quadratically varying doublets which are distributed over flat or curved panels. These panels are applied to the true surface geometry of arbitrarily shaped three dimensional aerodynamic configurations
Chebychev Trajectory Optimization Program /CHEBYTOP/ Final report
Digital computer program for interplanetary trajectory optimization and variable thrust dat
Induction probe determines levels of liquid metals
Mutual-inductance probe accurately measures liquid levels in a variety of liquid metals at elevated temperatures. It can be used in pyrochemical processes for the recovery of spent reactor fuel
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