Twist-controlled Resonant Tunnelling between Monolayer and Bilayer Graphene

We investigate the current-voltage characteristics of a field-effect tunnelling transistor comprised of both monolayer and bilayer graphene with well-aligned crystallographic axes, separated by three layers of hexagonal boron nitride. Using a self-consistent description of the device's electrostatic configuration we relate the current to three distinct tunable voltages across the system and hence produce a two-dimensional map of the I-V characteristics in the low energy regime. We show that the use of gates either side of the heterostructure offers a fine degree of control over the device's rich array of characteristics, as does varying the twist between the graphene electrodes.Comment: 5 pages including references and 3 figure

On the accurate long-time solution of the wave equation in exterior domains: Asymptotic expansions and corrected boundary conditions

We consider the solution of scattering problems for the wave equation using approximate boundary conditions at artificial boundaries. These conditions are explicitly viewed as approximations to an exact boundary condition satisfied by the solution on the unbounded domain. We study the short and long term behavior of the error. It is provided that, in two space dimensions, no local in time, constant coefficient boundary operator can lead to accurate results uniformly in time for the class of problems we consider. A variable coefficient operator is developed which attains better accuracy (uniformly in time) than is possible with constant coefficient approximations. The theory is illustrated by numerical examples. We also analyze the proposed boundary conditions using energy methods, leading to asymptotically correct error bounds

The supermassive black hole in NGC4486a detected with SINFONI at the VLT

The near-infrared integral field spectrograph SINFONI at the ESO VLT opens a new window for the study of central supermassive black holes. With a near-IR spatial resolution similar to HST optical and the ability to penetrate dust it provides the possibility to explore the low-mass end of the M-sigma relation (sigma<120km/s) where so far very few black hole masses were measured with stellar dynamics. With SINFONI we observed the central region of the low-luminosity elliptical galaxy NGC4486a at a spatial resolution of ~0.1arcsec in the K band. The stellar kinematics was measured with a maximum penalised likelihood method considering the region around the CO absorption band heads. We determined a black hole mass of M_BH=1.25^{+0.75}_{-0.79} x 10^7 M_sun (90% C.L.) using the Schwarzschild orbit superposition method including the full 2-dimensional spatial information. This mass agrees with the predictions of the M-sigma relation, strengthening its validity at the lower sigma end.Comment: 7 pages, 7 figures. Accepted by MNRA

IMPACTS OF LIBERALIZING THE JAPANESE PORK MARKET

The Japanese pork market is protected by a complex set of restrictions, including a variable levy and an import tariff. The combination of these policies distorts the quantity, price, and form of Japanese pork imports. An important issue relevant to the liberalization of the Japanese pork market is the accurate measurement of the price wedge between Japanese and world pork prices. The analysis indicates that the tariff equivalent of the price wedge over the 1986-88 period was 44%. If the tariff equivalent of the price wedge is reduced over a ten-year period, Japanese pork imports are projected to increase by over 39% initially and by over 215% compared to baseline projections by the year 2000. Producer welfare can be maintained by a deficiency payment scheme. A less costly alternative is an industry buffer scheme, which maintains the level of the pork industry for two years and then implements a declining deficiency payment scheme that limits the decrease in production levels to 5% per year.International Relations/Trade,

WESTERNIZATION IN CHINA: A CASE STUDY IN PROCESSED POTATOES

Keywords: China, potatoes, westernization, food demand, convenience foods Abstract: The demand for convenience foods is growing around the world, especially in China. However, the contributing factors of this change in food preferences are still largely unknown. To measure this westernization trend, data from a survey of Chinese consumers in Beijing is evaluated using a multinomial ordered logit model to determine which consumer attributes influence the probability of consuming western foods such as French fries, mashed potatoes, and potato chips. Results show that higher income levels and positive opinions concerning western food taste have a significant influence on increased consumption of all three processed potato products. Additionally, younger ages and female gender were highly significant indicators of increased French fry and potato chip consumption.Crop Production/Industries,

Experimental studies of perceptual processes, section four Progress report, Jan. 1 - Nov. 30, 1965

Effects of neurochemical drug on behavior and ribonucleic acid measurement