39,397 research outputs found
Evidence of Klein tunneling in graphene p-n junctions
Transport through potential barriers in graphene is investigated using a set
of metallic gates capacitively coupled to graphene to modulate the potential
landscape. When a gate-induced potential step is steep enough, disorder becomes
less important and the resistance across the step is in quantitative agreement
with predictions of Klein tunneling of Dirac fermions up to a small correction.
We also perform magnetoresistance measurements at low magnetic fields and
compare them to recent predictions.Comment: Major changes made: 1) Taking into account properly the contribution
of the resistance of monopolar junctions to the odd part of the resistance.
To better present the results we use a fitting parameter for the amplitude of
screening in graphene. 2) Wrong data for the diffusive model in figures 3, 9
and 10 was plotted in former version. 3) Figure 5 moved to EPAP
Rigorous Bounds to Retarded Learning
We show that the lower bound to the critical fraction of data needed to infer
(learn) the orientation of the anisotropy axis of a probability distribution,
determined by Herschkowitz and Opper [Phys.Rev.Lett. 86, 2174 (2001)], is not
always valid. If there is some structure in the data along the anisotropy axis,
their analysis is incorrect, and learning is possible with much less data
points.Comment: 1 page, 1 figure. Comment accepted for publication in Physical Review
Letter
Effects of high and low barometric pressures on susceptibility and resistance to infection Quarterly status report, 1 Apr. - 30 Jun. 1969
Effects of atmospheric pressure on susceptibility and resistance to infectio
Effects of high and low barometric pressures on susceptibility and resistance to infection Quarterly status report, 1 Oct. - 31 Dec. 1968
Effects of high and low barometric pressures on susceptibility and resistance to infection in mic
Effects of high and low barometric pressures on susceptibility and resistance to infection Quarterly status report, 1 Jul. - 30 Sep. 1969
Atmospheric pressure effects on mice resistance to bacterial or virus infection
Inelastic collisions of relativistic electrons with atomic targets assisted by a laser field
We consider inelastic collisions between relativistic electrons and atomic
targets assisted by a low-frequency laser field in the case when this field is
still much weaker than the typical internal fields in the target. Concentrating
on target transitions we show that they can be substantially affected by the
presence of the laser field. This may occur either via strong modifications in
the motion of the relativistic electrons caused by the electron-laser
interaction or via the Compton effect when the incident electrons convert laser
photon(s) into photons with frequencies equal to target transition frequencies.Comment: 4 pages, 2 figure
Space shuttle orbiter test flight series
The proposed studies on the space shuttle orbiter test taxi runs and captive flight tests were set forth. The orbiter test flights, the approach and landing tests (ALT), and the ground vibration tests were cited. Free flight plans, the space shuttle ALT crews, and 747 carrier aircraft crew were considered
Common-Resolution Convolution Kernels for Space- and Ground-Based Telescopes
Multi-wavelength study of extended astronomical objects requires combining
images from instruments with differing point spread functions (PSFs). We
describe the construction of convolution kernels that allow one to generate
(multi-wavelength) images with a common PSF, thus preserving the colors of the
astronomical sources. We generate convolution kernels for the cameras of the
Spitzer Space Telescope, Herschel Space Observatory, Galaxy Evolution Explorer
(GALEX), Wide-field Infrared Survey Explorer (WISE), ground-based optical
telescopes (Moffat functions and sum of Gaussians), and Gaussian PSFs. These
kernels allow the study of the Spectral Energy Distribution (SED) of extended
objects, preserving the characteristic SED in each pixel. The convolution
kernels and the IDL packages used to construct and use them are made publicly
available
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