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

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

Spin-dependent transport in a quasiballistic quantum wire

We describe the transport properties of a 5 $\mu$m long one-dimensional (1D) quantum wire. Reduction of conductance plateaux due to the introduction of weakly disorder scattering are observed. In an in-plane magnetic field, we observe spin-splitting of the reduced conductance steps. Our experimental results provide evidence that deviation from conductance quantisation is very small for electrons with spin parallel and is about 1/3 for electrons with spin anti-parallel. Moreover, in a high in-plane magnetic field, a spin-polarised 1D channel shows a plateau-like structure close to $0.3 \times e^2/h$ which strengthens with {\em increasing} temperatures. It is suggested that these results arise from the combination of disorder and the electron-electron interactions in the 1D electron gas.Comment: 4 pages, 5 figures, latex to be published in Phys. Rev. B (15/3/2000

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

Coulomb-Blockade directional coupler

A tunable directional coupler based on Coulomb Blockade effect is presented. Two electron waveguides are coupled by a quantum dot to an injector waveguide. Electron confinement is obtained by surface Schottky gates on single GaAs/AlGaAs heterojunction. Magneto-electrical measurements down to 350 mK are presented and large transconductance oscillations are reported on both outputs up to 4.2 K. Experimental results are interpreted in terms of Coulomb Blockade effect and the relevance of the present design strategy for the implementation of an electronic multiplexer is underlined.Comment: 4 pages, 4 figures, to be published in Applied Physics Letter