26,818 research outputs found
High-voltage pulse generator developed for wide-gap spark chambers
Low-inductance, high-capacitance Marx pulse generator provides for minimization of internal inductance and suppression of external electromagnetic radiation. The spark gaps of the generator are enclosed in a pressurized nitrogen atmosphere which allows the charging voltage to be varied by changing the nitrogen pressure
The crustal structure and tectonics of South America
A preliminary crustal structure map and a bibliography of crustal and upper mantle studies for South America are given. Work on the surface wave analysis and tectonic characterizations continues
Application of MAGSAT to lithospheric modeling in South America
Progress in the determination of relations of MAGSAT anomalies to lithospheric structures is reported. The prime emphasis was on a Rayleigh wave study and the determination of both group and phase velocity dispersion
Evaluation of existing knowledge of the tectonic history and lithospheric structure of South America
While data is available on the lithospheric and crustal structure of the Andes region of South America, there is limited knowledge of these aspects of the eastern portion of the continent. For this reason, a surface wave dispersion study of the area was initiated. Long period seismograms were obtained for a tripartite analysis of dispersion. A flow chart of the analysis to be conducted is presented along with a preliminary geologic/tectonic map that was prepared. Efforts to characterize the provinces identified in terms of their geological and geophysical parameters continue
Crustal and upper mantle structure data analysis
Approximately 50 seismograms obtained from the National Geophysical and Solar-Terrestrial Data Center were digitized and analysis of surface wave dispersion was begun
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Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To assess whether blue-light filtering spectacle lenses impart effects on visual function, provide protection to the macula, or both. We will also examine potential effects on the sleep-wake cycle
Phase transition and correlation decay in Coupled Map Lattices
For a Coupled Map Lattice with a specific strong coupling emulating
Stavskaya's probabilistic cellular automata, we prove the existence of a phase
transition using a Peierls argument, and exponential convergence to the
invariant measures for a wide class of initial states using a technique of
decoupling originally developed for weak coupling. This implies the exponential
decay, in space and in time, of the correlation functions of the invariant
measures
Irrelevant Interactions without Composite Operators - A Remark on the Universality of Second Order Phase Transitions
We study the critical behaviour of symmetric theory including
irrelevant terms of the form in the bare action,
where is the UV cutoff (corresponding e.g. to the inverse lattice
spacing for a spin system). The main technical tool is renormalization theory
based on the flow equations of the renormalization group which permits to
establish the required convergence statements in generality and rigour. As a
consequence the effect of irrelevant terms on the critical behaviour may be
studied to any order without using renormalization theory for composite
operators. This is a technical simplification and seems preferable from the
physical point of view. In this short note we restrict for simplicity to the
symmetry class of the Ising model, i.e. one component theory. The
method is general, however.Comment: 13 page
Zero-field superfluid density in d-wave superconductor evaluated from the results of muon-spin-rotation experiments in the mixed state
We report on measurements of the in-plane magnetic penetration \lambda_{ab}
in the optimally doped cuprate superconductor (BiPb)_2(SrLa)_2CuO_6+\delta (OP
Bi2201) by means of muon-spin rotation (\muSR). We show that in unconventional
wave superconductors (like OP Bi2201), \muSR experiments conducted in
various magnetic fields allow to evaluate the zero-field magnetic penetration
depth \lambda_0, which relates to the zero-field superfluid density in terms of
\rho_s\propto\lambda_0^-2.Comment: 4 pages, 5 figure
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