5,060 research outputs found
Quasiclassical approach to the spin-Hall effect in the two-dimensional electron gas
We study the spin-charge coupled transport in a two-dimensional electron
system using the method of quasiclassical (-integrated) Green's functions.
In particular we derive the Eilenberger equation in the presence of a generic
spin-orbit field. The method allows us to study spin and charge transport from
ballistic to diffusive regimes and continuity equations for spin and charge are
automatically incorporated. In the clean limit we establish the connection
between the spin-Hall conductivity and the Berry phase in momentum space. For
finite systems we solve the Eilenberger equation numerically for the special
case of the Rashba spin-orbit coupling and a two-terminal geometry. In
particular, we calculate explicitly the spin-Hall induced spin polarization in
the corners, predicted by Mishchenko et al. [13]. Furthermore we find universal
spin currents in the short-time dynamics after switching on the voltage across
the sample, and calculate the corresponding spin-Hall polarization at the
edges. Where available, we find perfect agreement with analytical results.Comment: 9 pages, 6 figure
Comment on "Magnetic response of Disordered Metallic Rings: Large Contributions of Far Levels"
Comment on cond-mat/0205390; PRL 90, 026805 (2003
Measurement of energy eigenstates by a slow detector
We propose a method for a weak continuous measurement of the energy
eigenstates of a fast quantum system by means of a "slow" detector. Such a
detector is only sensitive to slowly-changing variables, e. g. energy, while
its back-action can be limited solely to decoherence of the eigenstate
superpositions. We apply this scheme to the problem of detection of quantum
jumps between energy eigenstates in a harmonic oscillator.Comment: 4 page
Effect of the Strawberry Genotype, Cultivation and Processing on the Fra a 1 Allergen Content
Birch pollen allergic patients show cross-reactivity to vegetables and fruits, including
strawberries (Fragaria × ananassa). The objective of this study was to quantify the level of the
Fra a 1 protein, a Bet v 1-homologous protein in strawberry fruits by a newly developed ELISA,
and determine the effect of genotype, cultivation and food processing on the allergen amount.
An indirect competitive ELISA using a specific polyclonal anti-Fra a 1.02 antibody was established
and revealed high variability in Fra a 1 levels within 20 different genotypes ranging from 0.67
to 3.97 μg/g fresh weight. Mature fruits of red-, white- and yellow-fruited strawberry cultivars
showed similar Fra a 1 concentrations. Compared to fresh strawberries, oven and solar-dried
fruits contained slightly lower levels due to thermal treatment during processing. SDS-PAGE and
Western blot analysis demonstrated degradation of recombinant Fra a 1.02 after prolonged (>10 min)
thermal treatment at 99 â—¦ C. In conclusion, the genotype strongly determined the Fra a 1 quantity
in strawberries and the color of the mature fruits does not relate to the amount of the PR10-protein.
Cultivation conditions (organic and conventional farming) do not affect the Fra a 1 level, and seasonal
effects were minor
Improved high pressure turbine shroud
A new high pressure turbine shroud material has been developed from the consolidation of prealloyed powders of Ni, Cr, Al and Y. The new material, a filler for cast turbine shroud body segments, is called Genaseal. The development followed the identification of oxidation resistance as the primary cause of prior shroud deterioration, since conversion to oxides reduces erosion resistance and increases spalling under thermal cycled engine conditions. The NICrAlY composition was selected in preference to NIAL and FeCRALY alloys, and was formulated to a prescribed density range that offers suitable erosion resistance, thermal conductivity and elastic modulus for improved behavior as a shroud
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