Range and structure of ambient density from 30 to 120 km altitude

Range and structure of atmospheric density from 30 to 120 km - analysis of statistical models and deviations from U.S. standard and Patrick reference atmosphere

Preferential antiferromagnetic coupling of vacancies in graphene on SiO_2: Electron spin resonance and scanning tunneling spectroscopy

Monolayer graphene grown by chemical vapor deposition and transferred to SiO_2 is used to introduce vacancies by Ar^+ ion bombardment at a kinetic energy of 50 eV. The density of defects visible in scanning tunneling microscopy (STM) is considerably lower than the ion fluence implying that most of the defects are single vacancies. The vacancies are characterized by scanning tunneling spectroscopy (STS) on graphene and HOPG exhibiting a peak close to the Fermi level. The peak persists after air exposure up to 180 min, albeit getting broader. After air exposure for less than 60 min, electron spin resonance (ESR) at 9.6 GHz is performed. For an ion flux of 10/nm^2, we find a signal corresponding to a g-factor of 2.001-2.003 and a spin density of 1-2 spins/nm^2. The ESR signal consists of a mixture of a Gaussian and a Lorentzian of equal weight exhibiting a width down to 0.17 mT, which, however, depends on details of the sample preparation. The g-factor anisotropy is about 0.02%. Temperature dependent measurements reveal antiferromagnetic correlations with a Curie-Weiss temperature of -10 K. Albeit the electrical conductivity of graphene is significantly reduced by ion bombardment, the spin resonance induced change in conductivity is below 10^{-5}.Comment: 10 pages, 5 figures, discussion on STM images in the literature of defects in graphene adde

Scanning tunneling spectroscopy of a dilute two-dimensional electron system exhibiting Rashba spin splitting

Using scanning tunneling spectroscopy (STS) at 5 K in B-fields up to 7 T, we investigate the local density of states of a two-dimensional electron system (2DES) created by Cs adsorption on p-type InSb(110). The 2DES, which in contrast to previous STS studies exhibits a 2D Fermi level, shows standing waves at B = 0 T with corrugations decreasing with energy and with wave numbers in accordance with theory. In magnetic field percolating drift states are observed within the disorder broadened Landau levels. Due to the large electric field perpendicular to the surface, a beating pattern of the Landau levels is found and explained quantitatively by Rashba spin splitting within the lowest 2DES subband. The Rashba splitting does not contribute significantly to the standing wave patterns in accordance with theory.Comment: 9 pages, 9 figures, submitted to Phys. Rev.

Impact of Carbon Price Policies on U.S. Industry

This paper informs the discussion of carbon price policies by examining the potential for adverse impacts on domestic industries, with a focus on detailed sector-level analysis. The assumed policy scenario involves a unilateral economy-wide $10/ton CO2 charge without accompanying border tax adjustments or other complementary policies. Four modeling approaches are developed as a proxy for the different time horizons over which firms can pass through added costs, change input mix, adopt new technologies, and reallocate capital. Overall, we find that a readily identifiable set of industries experience particularly adverse impacts as measured by reduced output and that the relative burdens on different industries are remarkably consistent across the four time horizons. Output rebounds considerably over longer time horizons, and the adverse impacts on profits diminish even more rapidly in most cases. Over the short term employment losses mirror output declines, while gains in other industries fully offset the losses over the longer horizons. At the same time, leakage abroad is considerable in some sectors, particularly when reductions in exports are considered.carbon price, competitiveness, input-output analysis

Probing electron-electron interaction in quantum Hall systems with scanning tunneling spectroscopy

Using low-temperature scanning tunneling spectroscopy applied to the Cs-induced two-dimensional electron system (2DES) on p-type InSb(110), we probe electron-electron interaction effects in the quantum Hall regime. The 2DES is decoupled from p-doped bulk states and exhibits spreading resistance within the insulating quantum Hall phases. In quantitative agreement with calculations we find an exchange enhancement of the spin splitting. Moreover, we observe that both the spatially averaged as well as the local density of states feature a characteristic Coulomb gap at the Fermi level. These results show that electron-electron interaction effects can be probed down to a resolution below all relevant length scales.Comment: supplementary movie in ancillary file

Setting priorities for stroke care and research

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99062/1/ijs12153.pd

On the construction of evolution equations admitting a master symmetry

A method for constructing evolution equations admitting a master symmetry is proposed. Several examples illustrating the method are presented. It is also noted that for certain evolution equations master symmetries can be useful for obtaining new conservation laws from a given one