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

The impact of treewidth on ASP grounding and solving of Answer Set Programs

Peer reviewe

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