20,072 research outputs found
Advances in induction-heated plasma torch technology
Continuing research has resulted in significant advances in induction-heated plasma torch technology which extend and enhance its potential for broad range of uses in chemical processing, materials development and testing, and development of large illumination sources. Summaries of these advances are briefly described
High electrical resistivity carbon/graphite fibers
Carbon/graphite fibers were chemically oxidized in the liquid phase to fibers of graphite oxide. Resistivity increases as high as 10,000 times were obtained, the oxidized fiber decomposed on exposure to atmosphere. A factor of 1,000 remained as a stable increment. The largest change observed was 1,000,000 times. Best results were obtained on the most highly graphitized fibers. Electrochemical oxidation yielded a lower increase--about 10 times, but provided a controllable method of synthesis and insight to the mechanism of reaction. Tensile tests indicated that the strength of the fiber on oxidation was decreased by no more than 25 percent
Induction plasma nozzle tests
Simulation of nozzle environment in gas core nuclear rocket with induction coupled arc plasma syste
Neutrino-induced nucleosynthesis and the site of the r process
If the r process occurs deep within a type II supernova, probably the most popular of the proposed sites, abundances of r-process elements may be altered by the intense neutrino flux. We point out that the effects would be especially pronounced for eight isotopes that can be efficiently synthesized by the neutrino reactions following r-process freeze-out. We show that the observed abundances of these isotopes are entirely consistent with neutrino-induced nucleosynthesis, strongly arguing for a supernova r-process site. The deduced neutrino fluences place stringent constraints on the freeze-out radius and dynamic time scale of the r process
The Productivity of Pharmaceuticals in Improving Health: An Analysis of the OECD Health Data
Although a number of studies have been conducted on health production functions, little attention has been given to pharmaceuticals as a separate input into the production of health. Building upon existing published work, this paper uses an alternative specification and more recent data to estimate the effect of pharmaceutical expenditures on levels of health in the member countries of the Organization for Economic Cooperation and Development (OECD). In a sample of developed countries, we found that pharmaceutical consumption, as measured by per capita drug expenditures, has a positive effect on life expectancy at advanced ages. The marginal effect of pharmaceutical consumption is consistent with estimates that have been reported previously but appears to decline with increasing age. Over the past few years, the substantial and disproportionate growth of pharmaceutical expenditures for public and private payers in the U.S. has led to calls for regulatory intervention (e.g., price controls). However, our research suggests that increases in drug spending may yield further increases in life expectancy.Health production, life expectancy, pharmaceuticals, OECD, ecological studies
Entanglement signature in the mode structure of a single photon
It is shown that entanglement, which is a quantum correlation property of at
least two subsystems, is imprinted in the mode structure of a single photon.
The photon, which is emitted by two coupled cavities, carries the information
on the concurrence of the two intracavity fields. This can be useful for
recording the entanglement dynamics of two cavity fields and for entanglement
transfer.Comment: 4 pages, 3 figure
Cavity-assisted spontaneous emission as a single-photon source: Pulse shape and efficiency of one-photon Fock state preparation
Within the framework of exact quantum electrodynamics in dispersing and
absorbing media, we have studied the quantum state of the radiation emitted
from an initially in the upper state prepared two-level atom in a high-
cavity, including the regime where the emitted photon belongs to a wave packet
that simultaneously covers the areas inside and outside the cavity. For both
continuing atom--field interaction and short-term atom--field interaction, we
have determined the spatio-temporal shape of the excited outgoing wave packet
and calculated the efficiency of the wave packet to carry a one-photon Fock
state. Furthermore, we have made contact with quantum noise theories where the
intracavity field and the field outside the cavity are regarded as
approximately representing independent degrees of freedom such that two
separate Hilbert spaces can be introduced.Comment: 16 pages, 7 eps figures; improved version as submitted to Phys. Rev.
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