87,650 research outputs found
Salt-gradient Solar Ponds: Summary of US Department of Energy Sponsored Research
The solar pond research program conducted by the United States Department of Energy was discontinued after 1983. This document summarizes the results of the program, reviews the state of the art, and identifies the remaining outstanding issues. Solar ponds is a generic term but, in the context of this report, the term solar pond refers specifically to saltgradient solar pond. Several small research solar ponds have been built and successfully tested. Procedures for filling the pond, maintaining the gradient, adjusting the zone boundaries, and extracting heat were developed. Theories and models were developed and verified. The major remaining unknowns or issues involve the physical behavior of large ponds; i.e., wind mixing of the surface, lateral range or reach of horizontally injected fluids, ground thermal losses, and gradient zone boundary erosion caused by pumping fluid for heat extraction. These issues cannot be scaled and must be studied in a large outdoor solar pond
Evidence from scanning tunneling microscopy in support of a structural model for the InSb(001)-c(8×2) surface
In this letter we present evidence from scanning tunneling microscopy studies in support of a recently proposed structural model for the indium-terminated c(8×2) surface of InSb(001). This structural model, by Norris and co-workers, is based on a surface x-ray diffraction study [Surf. Sci. 409, 27 (1998)], and represents a significant departure from previously suggested models for the c(8×2) reconstruction on any (001) surface of the common III–V semiconductor materials. Although filled state images of the InSb(001)-c(8×2) surface have previously been published, empty states image of sufficient quality to extract any meaningful information have not previously been reported. The observations are in excellent agreement with the recently proposed model for this surface reconstruction
Hypersonic test facility Patent
Hypersonic test facility for studying ablation in models under high pressure and high temperatur
Estimating the sensitivity of wide-parameter-space searches for gravitational-wave pulsars
This paper presents an in-depth study of how to estimate the sensitivity of
searches for gravitational-wave pulsars -- rapidly-rotating neutron stars which
emit quasi-sinusoidal gravitational waves. It is particularly concerned with
searches over a wide range of possible source parameters, such as searches over
the entire sky and broad frequency bands. Traditional approaches to estimating
the sensitivity of such searches use either computationally-expensive Monte
Carlo simulations, or analytic methods which sacrifice accuracy by making an
unphysical assumption about the population of sources being searched for. This
paper develops a new, analytic method of estimating search sensitivity which
does not rely upon this unphysical assumption. Unlike previous analytic
methods, the new method accurately predicts the sensitivity obtained using
Monte Carlo simulations, while avoiding their computational expense. The change
in estimated sensitivity due to properties of the search template bank, and the
geographic configuration of the gravitational wave detector network, are also
investigated.Comment: 16 figures, 2 tables, REVTeX 4.1; minor typos corrected from v2,
updated reference
Analytic results for particles with interaction in two dimensions and an external magnetic field
The -dimensional quantum problem of particles (e.g. electrons) with
interaction in a two-dimensional parabolic potential
(e.g. quantum dot) and magnetic field , reduces exactly to solving a
-dimensional problem which is independent of and . An
exact, infinite set of relative mode excitations are obtained for any . The
problem reduces to that of a ficticious particle in a two-dimensional,
non-linear potential of strength , subject to a ficticious magnetic
field , the relative angular momentum.Comment: To appear in Physical Review Letters (in press). RevTeX file. Two
figures available from [email protected] or
[email protected]
High-Fidelity Readout in Circuit Quantum Electrodynamics Using the Jaynes-Cummings Nonlinearity
We demonstrate a qubit readout scheme that exploits the Jaynes-Cummings
nonlinearity of a superconducting cavity coupled to transmon qubits. We find
that in the strongly-driven dispersive regime of this system, there is the
unexpected onset of a high-transmission "bright" state at a critical power
which depends sensitively on the initial qubit state. A simple and robust
measurement protocol exploiting this effect achieves a single-shot fidelity of
87% using a conventional sample design and experimental setup, and at least 61%
fidelity to joint correlations of three qubits.Comment: 5 pages, 4 figure
The Mercury-Redstone project
Mercury-Redstone project development history, and contributions to future manned spacecraft design and operatio
The potential effect of an HIV/AIDS vaccine in South Africa
This paper presents a model for assessing the potential effect of an HIV/AIDS vaccine in South Africa, and for calculating the amount of vaccine that would be required. A number of different hypothetical vaccine profiles and vaccine distribution strategies are considered. Results suggest that a sterilising vaccine could reduce the HIV incidence between 2015 and 2025 by up to 50%, while a disease modifying vaccine would be unlikely to reduce HIV incidence by more than a third. The effect on AIDS mortality over the same period would be substantially smaller, and it is unlikely that any preventive vaccine would reduce AIDS mortality by more than 10% between 2015 and 2025
The potential effect of an HIV/AIDS vaccine in South Africa
This paper presents a model for assessing the potential effect of an HIV/AIDS vaccine in South Africa, and for calculating the amount of vaccine that would be required. A number of different hypothetical vaccine profiles and vaccine distribution strategies are considered. Results suggest that a sterilising vaccine could reduce the HIV incidence between 2015 and 2025 by up to 50%, while a disease modifying vaccine would be unlikely to reduce HIV incidence by more than a third. The effect on AIDS mortality over the same period would be substantially smaller, and it is unlikely that any preventive vaccine would reduce AIDS mortality by more than 10% between 2015 and 2025
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