8,007 research outputs found
Antisymmetric magnetoresistance in magnetic multilayers with perpendicular anisotropy
While magnetoresistance (MR) has generally been found to be symmetric in
applied field in non-magnetic or magnetic metals, we have observed
antisymmetric MR in Co/Pt multilayers. Simultaneous domain imaging and
transport measurements show that the antisymmetric MR is due to the appearance
of domain walls that run perpendicular to both the magnetization and the
current, a geometry existing only in materials with perpendicular magnetic
anisotropy. As a result, the extraordinary Hall effect (EHE) gives rise to
circulating currents in the vicinity of the domain walls that contributes to
the MR. The antisymmetric MR and EHE have been quantitatively accounted for by
a theoretical model.Comment: 17 pages, 4 figure
Multilevel semantic analysis and problem-solving in the flight domain
A computer based cockpit system which is capable of assisting the pilot in such important tasks as monitoring, diagnosis, and trend analysis was developed. The system is properly organized and is endowed with a knowledge base so that it enhances the pilot's control over the aircraft while simultaneously reducing his workload
Dynamical mean-field equations for strongly interacting fermionic atoms in a potential trap
We derive a set of dynamical mean-field equations for strongly interacting
fermionic atoms in a potential trap across a Feshbach resonance. Our derivation
is based on a variational ansatz, which generalizes the crossover wavefunction
to the inhomogeneous case, and the assumption that the order parameter is
slowly varying over the size of the Cooper pairs. The equations reduce to a
generalized time-dependent Gross-Pitaevskii equation on the BEC side of the
resonance. We discuss an iterative method to solve these mean-field equations,
and present the solution for a harmonic trap as an illustrating example to
self-consistently verify the approximations made in our derivation.Comment: replaced with the published versio
Quantum Anomalous Hall Effect in HgMnTe Quantum Wells
The quantum Hall effect is usually observed when the two-dimensional electron
gas is subjected to an external magnetic field, so that their quantum states
form Landau levels. In this work we predict that a new phenomenon, the quantum
anomalous Hall effect, can be realized in HgMnTe quantum wells,
without the external magnetic field and the associated Landau levels. This
effect arises purely from the spin polarization of the atoms, and the
quantized Hall conductance is predicted for a range of quantum well thickness
and the concentration of the atoms. This effect enables dissipationless
charge current in spintronics devices.Comment: 5 pages, 3 figures. For high resolution figures see final published
version when availabl
Passenger transmission and productiveness of transit lines with high loads
Deterministic transit capacity analysis applies to planning, design and operational management of urban transit systems. The Transit Capacity and Quality of Service Manual (1) and Vuchic (2, 3) enable transit performance to be quantified and assessed using transit capacity and productive capacity. This paper further defines important productive performance measures of an individual transit service and transit line. Transit work (p-km) captures the transit task performed over distance. Passenger transmission (p-km/h) captures the passenger task delivered by service at speed. Transit productiveness (p-km/h) captures transit work performed over time. These measures are useful to operators in understanding their services’ or systems’ capabilities and passenger quality of service. This paper accounts for variability in utilized demand by passengers along a line and high passenger load conditions where passenger pass-up delay occurs. A hypothetical case study of an individual bus service’s operation demonstrates the usefulness of passenger transmission in comparing existing and growth scenarios. A hypothetical case study of a bus line’s operation during a peak hour window demonstrates the theory’s usefulness in examining the contribution of individual services to line productive performance. Scenarios may be assessed using this theory to benchmark or compare lines and segments, conditions, or consider improvements
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