1,491 research outputs found
Veselago lensing in graphene with a p-n junction: classical versus quantum effects
The feasibility of Veselago lensing in graphene with a p-n junction is
investigated numerically for realistic injection leads. Two different set-ups
with two narrow leads are considered with absorbing or reflecting side edges.
This allows us to separately determine the influence of scattering on electron
focusing for the edges and the p-n interface. Both semiclassical and
tight-binding simulations show a distinctive peak in the transmission
probability that is attributed to the Veselago lensing effect. We investigate
the robustness of this peak on the width of the injector, the position of the
p-n interface and different gate potential profiles. Furthermore, the influence
of scattering by both short- and long-range impurities is considered.Comment: 10 pages, 7 figure
Omni-directional L-band antenna for mobile communications
The principle and design of an L-band omni-directional mobile communication antenna are discussed. The antenna is a circular wave guide aperture with hybrid circuits attached to higher order mode excitation. It produces polarized and symmetric two split beams in elevation. The circular waveguide is fed by eight probes with a 90 degree phase shift between their inputs. Radiation pattern characteristics are controlled by adjusting the aperture diameter and mode excitation. This antenna satisfies gain requirements as well as withstanding the harsh environment
Low Temperature Susceptibility of the Noncentrosymmetric Superconductor CePt_3Si
We report ac susceptibility measurements of polycrystalline CePt_3Si down to
60 mK and in applied fields up to 9 T. In zero field, a full Meissner state
emerges at temperatures T/Tc < 0.3, where Tc=0.65 K is the onset transition
temperature. Though transport measurements show a relatively high upper
critical field Bc2 ~ 4-5 T, the low temperature susceptibility, \chi', is quite
fragile to applied field, with \chi' diminishing rapidly in fields of a few kG.
Interestingly, the field dependence of \chi' is well described by the power
law, 4\pi\chi'=(B/B_c)^{1/2}, where Bc is the field at which the onset of
resistance is observed in transport measurements.Comment: 5 figure
Does economic policy uncertainty impact inflation?
Using the monthly economic policy uncertainty (EPU) index of Baker et al. (2016), we examine its impact on inflation rate in the UK over the period from 1998 to 2020. We adopt a vector autoregressive (VAR) model and generate impulse response functions. To ensure that the identified shocks will be uncorrelated, based on economic theoretical considerations, we employed Cholesky restrictions. The results show that a positive innovation in EPU index leads to a weakening of the real exchange rate and unemployment rate and at the same time a rise in inflation rate. The broad implication of the present research is that under economic policy uncertainty shocks, inflation and unemployment rate respond in accordance with the effects described by the economic theory and the Phillips curve, which emphasizes that there is a trade-off between inflation and unemployment.info:eu-repo/semantics/publishedVersio
Swimming Efficiency of Bacterium Escherichia Coli
We use in vivo measurements of swimming bacteria in an optical trap to
determine fundamental properties of bacterial propulsion. In particular, we
determine the propulsion matrix, which relates the angular velocity of the
flagellum to the torques and forces propelling the bacterium. From the
propulsion matrix dynamical properties such as forces, torques, swimming speed
and power can be obtained from measurements of the angular velocity of the
motor. We find significant heterogeneities among different individuals even
though all bacteria started from a single colony. The propulsive efficiency,
defined as the ratio of the propulsive power output to the rotary power input
provided by the motors, is found to be 0.2%.Comment: 6 page
Shall Be Bright at Last: Reflections on Suffering and Hope in the Letters of Paul
These nine essays on suffering offer exercises in Christian hope. The contributors reveal honest and tender wounds of the many harsh realities of life in a broken world awaiting full redemption. They meditate on Paul\u27s holy words that teach us to pray with expectation and live by faith. They encourage fellow pilgrims to trust the path and stick together.
Shall Be Bright at Last is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.
CC BY-NC-SAhttps://digitalcommons.georgefox.edu/monographs/1000/thumbnail.jp
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