44,316 research outputs found
Ultraviolet solid state spectroscopy in the spectral region 3000 - 300 A Final report, 1 Oct. 1960 - 1 Dec. 1969
Summary of research in solid state spectroscopy on variety of material
Optical Constants of Magnesium Oxide in the Far Ultraviolet
Optical constants of magnesium oxide in far ultraviole
Prospects for an orbital determination and capture cell experiment
A dust experiment which combines measurements of the elemental and isotopic composition of individual particles with orbital information would contribute fundamental, new scientific information on the sources contributing to the micrometeoroid population. The general boundary conditions for such a system are: (1) it must be capable of measuring velocities in the range of 10 km/sec to 100 km/sec with several percent accuracy; (2) it must collect particles in such a way that the debris atoms are locally concentrated so that precise isotopic measurements are possible; (3) it should collect particles over a wide range of sizes starting with a lower limit of 10 microns; (4) it should incorporate materials that will not compromise the isotopic measurements; and (5) it should be large enough to obtain statistically meaningful results within a reasonable exposure time. Techniques which may satisfy these conditions are described
Ground effects on Loran-C signals
In conjunction with the test and evaluation of the position fixing capabilities of the Army Manpack Loran Receiver AN/PSN-6, an extensive series of time difference and signal amplitude measurements were made within a 100 km map grid square encompassing Fort Monmouth, New Jersey. The test location is within the coverage area of the East Coast Loran-C Chain. The data were used to develop a simple smooth-earth model for the test area as well as to estimate the magnitude and distributions of deviations from this model. Local propagation processes associated with topographic features and the grid of overhead wires in the test area are shown to contribute to the deviations from the model
Optical Constants of Lithium Fluoride in the Far Ultraviolet
Optical constants of lithium fluoride in far ultraviole
Electromagnetic Polarizabilities: Lattice QCD in Background Fields
Chiral perturbation theory makes definitive predictions for the extrinsic
behavior of hadrons in external electric and magnetic fields. Near the chiral
limit, the electric and magnetic polarizabilities of pions, kaons, and nucleons
are determined in terms of a few well-known parameters. In this limit, hadrons
become quantum mechanically diffuse as polarizabilities scale with the inverse
square-root of the quark mass. In some cases, however, such predictions from
chiral perturbation theory have not compared well with experimental data.
Ultimately we must turn to first principles numerical simulations of QCD to
determine properties of hadrons, and confront the predictions of chiral
perturbation theory. To address the electromagnetic polarizabilities, we
utilize the background field technique. Restricting our attention to
calculations in background electric fields, we demonstrate new techniques to
determine electric polarizabilities and baryon magnetic moments for both
charged and neutral states. As we can study the quark mass dependence of
observables with lattice QCD, the lattice will provide a crucial test of our
understanding of low-energy QCD, which will be timely in light of ongoing
experiments, such as at COMPASS and HI\gamma S.Comment: 3 pages, talk given by B. C. Tiburzi at PANIC 201
Planning for the mobile library: a strategy for managing innovation and transformation at the University of Glasgow Library
Modern mobile devices have powerful features that are transforming access to information. Lippincott argues that as mobile devices such as smartphones become ‘key information devices’ for our users, libraries will want to have a significant presence in offering content and services that are suitable for this medium. This article outlines the process of development and implementation of a mobile strategy at the University of Glasgow Library. What began as an investigation into a mobile interface to the library catalogue evolved into a comprehensive strategic review of how we deliver services now and in the future in this rapidly changing mobile environment
Quantum Non-Barking Dogs
Quantum weak measurements with states both pre- and postselected offer a
window into a hitherto neglected sector of quantum mechanics. A class of such
systems involves time dependent evolution with transitions possible. In this
paper we explore two very simple systems in this class. The first is a toy
model representing the decay of an excited atom. The second is the tunneling of
a particle through a barrier. The postselection criteria are chosen as follows:
at the final time, the "atom" remains in its initial excited state for the
first example and the particle remains behind the barrier for the second. We
then ask what weak values are predicted in the physical environment of the
"atom" (to which no net energy has been transferred) and in the region beyond
the barrier (to which the particle has not tunneled). Previous work suggests
that very large weak values might arise in these regions for long durations
between pre- and postselection times. Our calculations reveal some distinct
differences between the two model systems.Comment: 8 pages, 3 figure
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