Measurement of the electronic compressibility of bilayer graphene

We present measurements of the electronic compressibility, $K$, of bilayer graphene in both zero and finite magnetic fields up to 14 T, and as a function of both the carrier density and electric field perpendicular to the graphene sheet. The low energy hyperbolic band structure of bilayer graphene is clearly revealed in the data, as well as a sizable asymmetry between the conduction and valence bands. A sharp increase in $K^{-1}$ near zero density is observed for increasing electric field strength, signaling the controlled opening of a gap between these bands. At high magnetic fields, broad Landau level (LL) oscillations are observed, directly revealing the doubled degeneracy of the lowest LL and allowing for a determination of the disorder broadening of the levels.Comment: 5 pages, 3 figures; final version for publicatio

Quantum Hall Effect and Semimetallic Behavior of Dual-Gated ABA-Stacked Trilayer Graphene

The electronic structure of multilayer graphenes depends strongly on the number of layers as well as the stacking order. Here we explore the electronic transport of purely ABA-stacked trilayer graphenes in a dual-gated field-effect device configuration. We find that both the zero-magnetic-field transport and the quantum Hall effect at high magnetic fields are distinctly different from the monolayer and bilayer graphenes, and that they show electron-hole asymmetries that are strongly suggestive of a semimetallic band overlap. When the ABA trilayers are subjected to an electric field perpendicular to the sheet, Landau level splittings due to a lifting of the valley degeneracy are clearly observed.Comment: 5 figure

RXTE and ASCA Constraints on Non-thermal Emission from the A2256 Galaxy Cluster

An 8.3 hour observation of the Abell 2256 galaxy cluster using the Rossi X-ray Timing Explorer proportional counter array produced a high quality spectrum in the 2 - 30 keV range. Joint fitting with the 0.7 - 11 keV spectrum obtained with the Advanced Satellite for Astrophysics and Cosmology gas imaging spectrometer gives an upperlimit of 2.3x10^-7 photons/cm^2/sec/keV for non-thermal emission at 30 keV. This yields a lower limit to the mean magnetic field of 0.36 micro Gauss (uG) and an upperlimit of 1.8x10^-13 ergs/cm^3 for the cosmic-ray electron energy density. The resulting lower limit to the central magnetic field is ~1 - 3 uG While a magnetic field of ~0.1 - 0.2 uG can be created by galaxy wakes, a magnetic field of several uG is usually associated with a cooling flow or, as in the case of the Coma cluster, a subcluster merger. However, for A2256, the evidence for a merger is weak and the main cluster shows no evidence of a cooling flow. Thus, there is presently no satisfactory hypothesis for the origin of an average cluster magnetic field as high as >0.36 uG in the A2256 cluster.Comment: 8 pages, Astrophysical Journal (in press

Electronic structure and time-dependent description of rotational predissociation of LiH

Adiabatic potential energy curves of the $^1\Sigma^+$ and $^1\Pi$ states of the LiH molecule have been calculated. They correlate asymptotically to atomic states, like 2s+1s, 2p+1s, 3s+1s, 3p+1s, 3d+1s, 4s+1s, 4p+1s and 4d+1s. Very good agreement is found between our calculated spectroscopic parameters and experimental ones. The dynamics of the rotational predissociation process of the $1^1\Pi$ state has been studied by solving the time-dependent Schr\"{o}dinger equation. The classical experiment of Velasco [Can. J. Phys. {35}, 1204 (1957)] on dissociation in the $1^1\Pi$ state is explained in detail

Financial Feasibility of LEED Certified Buildings for Developers and Investors

This is a case study on a small to mid-size private equity firm that deals with real estate development as well as investment to find out the financial feasibility of LEED certified buildings in today’s building climate. Interviews with two investment analysts at this firm who are versed in LEED certification about how it is looked at in their company as well as the broader industry will give insights into the feasibility of developing or investing in environmentally friendly buildings. This impacts the real estate and construction industries due to the fact that developers and investors are often times a large part of the clientele for contractors. This paper will look to industry professionals to find out some of the conditions that are needed in order to make capital investments in LEED buildings, such as geographic location, tenant motivation, and large institutional sized products. The findings of this study were that for medium to small sized investors and developers focused on maximizing rate of return through short hold periods, there are little incentives to invest in LEED certified buildings, however the analysts acknowledge that there are benefits and could be effectively implemented in long term hold approaches or for very large institutional investments

Radio jet refraction in galactic atmospheres with static pressure gradients

A theory of double radio sources which have a 'Z' or 'S' morphology is proposed, based on the refraction of radio jets in the extended atmosphere of an elliptical galaxy. The model describes a collimated jet of supersonic material bending self-consistently under the influence of external static pressure gradients. Gravity and magnetic fields are neglected in the simplest case except insofar as they determine the static pressure distribution. The calculation is a straightforward extension of a method used to calculate a ram-pressure model for twin radio trails ('C' morphology). It may also be described as a continuous-jet version of a buoyancy model proposed in 1973. The model has the added virtue of invoking a galactic atmosphere similar to those already indicated by X-ray measurements of some other radio galaxies and by models for the collimation of other radio jets

A low power blood flow transmitter. Transmission of cardiovascular response to weightlessness Progress report, 1 Mar. - 31 May 1970

Low power blood flow transmitter to determine cardiovascular response to weightlessnes