17,811 research outputs found
Some interactions among driver, vehicle, and roadway variables in normal driving
Effects of road and vehicle conditions, visual warning signs, direction of turns, night time, and skill on automobile driver performance are studied in several experiments. Considered criteria are variability in speed and acceleration
Movie of the interplanetary magnetic field
Description of movie representing IMP-1 MAGNETOMETER observations of interplanetary magnetic fiel
Interplanetary magnetic field IMP-1, motion picture of the transverse components
Motion picture report of IMP-1 magnetometer observations of interplanetary magnetic fiel
Anomalous spin-dependent behaviour of one-dimensional subbands
We report a new electron interaction effect in GaAs/AlGaAs quantum wires.
Using DC-bias spectroscopy, we show that large and abrupt changes occur to the
energies of spin-down (lower energy) states as they populate. The effect is not
observed for spin-up energy states. At B=0, interactions have a pronounced
effect, in the form of the well-known 0.7 Structure. However, our new results
show that interactions strongly affect the energy spectrum at all magnetic
fields, from 0 to 16T, not just in the vicinity of the 0.7 Structure.Comment: 4 pages, 2 figure
All-electrical injection and detection of a spin polarized current using 1D conductors
All-electrical control of spin transport in nanostructures has been the
central interest and chal- lenge of spin physics and spintronics. Here we
demonstrate on-chip spin polarizing/filtering actions by driving the
gate-defined one dimensional (1D) conductor, one of the simplest geometries for
integrated quantum devices, away from the conventional Ohmic regime. Direct
measurement of the spin polarization of the emitted current was performed when
the momentum degeneracy was lifted, wherein both the 1D polarizer for spin
injection and the analyzer for spin detection were demonstrated. The results
showed that a configuration of gates and applied voltages can give rise to a
tunable spin polarization, which has implications for the development of
spintronic devices and future quantum information processing.Comment: 5 pages, 3 figure
Experimental analysis of multistatic multiband radar signatures of wind turbines
This study presents the analysis of recent experimental data acquired using two radar systems at S-band and X-band to measure simultaneous monostatic and bistatic signatures of operational wind turbines near Shrivenham, UK. Bistatic and multistatic radars are a potential approach to mitigate the adverse effects of wind farm clutter on the performance of radar systems, which is a well-known problem for air traffic control and air defence radar. This analysis compares the simultaneous monostatic and bistatic micro-Doppler signatures of two operational turbines and investigates the key differences at bistatic angles up to 23°. The variations of the signature with different polarisations, namely vertical transmitted and vertical received and horizontal transmitted and horizontal received, are also discussed
Sensitivity of the magnetic state of a spin lattice on itinerant electron orbital phase
Spatially extended localized spins can interact via indirect exchange
interaction through Friedel oscillations in the Fermi sea. In arrays of
localized spins such interaction can lead to a magnetically ordered phase.
Without external magnetic field such a phase is well understood via a
"two-impurity" Kondo model. Here we employ non-equilibrium transport
spectroscopy to investigate the role of the orbital phase of conduction
electrons on the magnetic state of a spin lattice. We show experimentally, that
even tiniest perpendicular magnetic field can influence the magnitude of the
inter-spin magnetic exchange.Comment: To be published in PhysicaE EP2DS proceedin
Experimental position-time entanglement with degenerate single photons
We report an experiment in which two-photon interference occurs between
degenerate single photons that never meet. The two photons travel in opposite
directions through our fibre-optic interferometer and interference occurs when
the photons reach two different, spatially separated, 2-by-2 couplers at the
same time. We show that this experiment is analogous to the conventional
Franson-type entanglement experiment where the photons are entangled in
position and time. We measure wavefunction overlaps for the two photons as high
as 94 3%.Comment: Updated to published version, new fig. 4., corrected typo
Ballistic electron spectroscopy
We demonstrate the feasibility of ballistic electron spectroscopy as a new
tool for mesoscopic physics. A quantum dot is utilised as an energy-selective
detector of non-equilibrium ballistic electrons injected into a two-dimensional
electron system. In this paper we use a second quantum dot as the electron
injector to evaluate the scheme. We propose an application in the study of
interacting 1D and 0D systems.Comment: 3 pages, 4 figure
- …
