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Point source
About: Point source is a research topic. Over the lifetime, 5077 publications have been published within this topic receiving 94091 citations.
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TL;DR: In this article, two Gaussian plume inverse approaches are described for estimating emission rates from ground-level point sources observed from remote vantage points, which are compared to a simple point source Gaussian emission estimation approach that is part of Draft EPA Method OTM 33A.
52 citations
TL;DR: In this paper, the authors consider quantitative acoustic emission (AE) techniques with real and simulated sources as powerful tools for investigating failure processes in composite materials using a simulated source acting as a point source and one or more point receivers whose characteristics are known.
52 citations
TL;DR: The solution for the ekonal equation with a point-source condition has an upwind singularity at the source point as the eikonal solution behaves like a distance function at and near the source.
Abstract: The solution for the eikonal equation with a point-source condition has an upwind singularity at the source point as the eikonal solution behaves like a distance function at and near the source. As...
52 citations
Patent•
01 Apr 1994TL;DR: In this article, a high repetition-rate laser plasma target source system and lithography system is described, which consists in a preferred embodiment of a liquid tank source and freezer which freezes microscopic particles into crystal shapes which are projected by a nozzle jet from a high- repetition rate liquid-droplet injector into the path of a flashing laser beam, which results in producing soft x-rays of approximately 13 nm.
Abstract: A high repetition-rate laser plasma target source system and lithography system is disclosed. The target source system comprises in a preferred embodiment a liquid tank source and freezer which freezes microscopic particles into crystal shapes which are projected by a nozzle jet from a high repetition rate liquid-droplet injector into the path of a flashing laser beam, which results in producing soft x-rays of approximately 13 nm. Uncollected and unshot target crystals are collected and reliquified by a heater source in order to be recycled back to the liquid tank source. Optionally an auxiliary source and detector system can be used to allow for instantaneous triggering of the laser beam. The target source system can be incorporated into well known EUV lithography systems for the production of wafer chips.
52 citations
TL;DR: In this article, a study of the density structure of the protostellar collapse candidate B335 using continuum observations from the IRAM Plateau de Bure Interferometer made at wavelengths of 1.2 and 3.0 mm is presented.
Abstract: We present a study of the density structure of the protostellar collapse candidate B335 using continuum observations from the IRAM Plateau de Bure Interferometer made at wavelengths of 1.2 and 3.0 mm. We analyze these data, which probe spatial scales from 5000 to 500 AU, directly in the visibility domain by comparison with synthetic observations constructed from models that assume different physical conditions. This approach allows for much more stringent constraints to be derived from the data than from analysis of images. A single radial power law in density provides a good description of the data, with a best-fit power-law density index p = 1.65 ± 0.05. Through simulations, we quantify the sensitivity of this result to various model uncertainties, including assumptions of temperature distribution, outer boundary, dust opacity spectral index, and an unresolved central component. The largest uncertainty comes from the unknown presence of a centralized point source. The maximal point source, with 1.2 mm flux of F = 12 ± 7 mJy, reduces the power-law density index to p = 1.47 ± 0.07. The remaining sources of systematic uncertainty, of which the most important is the radial dependence of the temperature distribution, likely contribute a total uncertainty at the level of δp 0.2. Taking into account the uncertainties, we find strong evidence that the power-law index of the density distribution within 5000 AU is significantly less than the value at larger radii, close to 2.0, from previous studies of dust emission and extinction. Images made from the data show clear departures from spherical symmetry, with the globule being slightly extended perpendicular to the outflow axis. The inclusion of a crude model of the outflow as a hollow bipolar cone of constant opening angle improves the fit and leaves the resulting density power-law index unchanged. These results conform well to the generic paradigm of isolated, low-mass star formation, which predicts a power-law density index close to p = 1.5 for an inner region of gravitational free fall onto the protostar. However, the standard inside-out collapse model does not fit the data as successfully as a simple p = 1.5 power law, because of the relative shallowness of the predicted density profile just within the infall radius.
52 citations