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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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Patent
29 Oct 2003
TL;DR: A laser module comprises a laser diode secured on a semiconductor substrate for emission of a forward laser beam from its front end and a backward beam from a point source on its rear end in a horizontal direction as discussed by the authors.
Abstract: A laser module comprises a laser diode secured on a semiconductor substrate for emission of a forward laser beam from its front end and a backward laser beam from a point source on its rear end in a horizontal direction A photodiode, also secured on the substrate, has a light receiving surface extending in the horizontal direction by length L from an edge proximate to the laser diode for receiving a lower half of the backward laser beam, the light receiving surface being lower than the point source by a vertical distance Y, the edge being spaced a horizontal distance Z from the point source of the laser diode, wherein the horizontal distance Z is equal to or greater than (Y/tan θ)−L, where θ is a vertical angle in which the lower half of the backward laser beam radiates from the point source

59 citations

Journal ArticleDOI
TL;DR: A new method to determine the location and shape of an unbounded rough surface from measurements of scattered electromagnetic waves based on the point source method of Potthast, which can reconstruct the total field when the incident field is not necessarily time harmonic.
Abstract: In this paper we propose a new method to determine the location and shape of an unbounded rough surface from measurements of scattered electromagnetic waves. The proposed method is based on the point source method of Potthast (IMA J. Appl. Math. 61, 119–140, 1998) for inverse scattering by bounded obstacles. We propose a version for inverse rough surface scattering which can reconstruct the total field when the incident field is not necessarily time harmonic. We present numerical results for the case of a perfectly conducting surface in TE polarization, in which case a homogeneous Dirichlet condition applies on the boundary. The results show great accuracy of reconstruction of the total field and of the prediction of the surface location.

59 citations

Patent
22 Feb 1980
TL;DR: A radiation sensor for determining the angular location of a light source and locating a direction defined by a plurality of sources fastened to a movable structure such as a helmet-mounted sight visor is described in this article.
Abstract: A radiation sensor for determining the angular location of a light source and locating a direction defined by a plurality of sources fastened to a movable structure such as a helmet-mounted sight visor. The sensor comprises a housing with an optical mask which is provided with transparent zones of circular shape, with the result that the omnidirectional radiation transmitted by a point source is confined within a cone. Radiation-detecting means constituted by linear arrays of photosensitive elements are disposed in a plane parallel to the mask so that the center of the projected circle corresponding to the angular direction of the source is determined by the positions of sensitized elements of the detecting strips.

59 citations

Journal ArticleDOI
TL;DR: In this article, the authors reported the results of 0.5-3.0 keV X-ray observations of the central region of the Perseus cluster carried out with the Imaging Proportional Counter and High Resolution Imager aboard the Einstein Observatory.
Abstract: We report the results of 0.5--3.0 keV X-ray observations of the central region of the Perseus cluster carried out with the Imaging Proportional Counter and High Resolution Imager aboard the Einstein Observatory. In addition to the very extended thermal cluster emission and a sharply peaked component at NGC 1275 previously known, the high resolution image reveals a point source coincident with the optical nucleus of NGC 1275. The 0.5--3.0 keV luminosity of the compact source is approx.10/sup 44/ ergs s/sup -1/.

59 citations

Journal ArticleDOI
TL;DR: In this article, the static displacement and strain fields caused by the introduction of a shear dislocation point source into a layered elastic half space have been evaluated using a Thomson-Haskell matrix method (Singh).
Abstract: Summary The static displacement and strain fields caused by the introduction of a shear dislocation point source into a layered elastic half space have been evaluated using a Thomson-Haskell matrix method (Singh). The point source was found to be an adequate representation of a fault at distances greater than four fault lengths. Gross earth structure (oceanic, shield and tectonic models) cause fields that differ little from those of a uniform half space. However, significant departures from the uniform half-space fields are found to be caused by low rigidity layers, both at the surface (representing sediment cover) and at depth (representing possible zones of partial melt). Both of these features cause complexities in the strain fields that depend on the source orientation and source-receiver distance, and these may result in amplification or attenuation of the uniform halfspace fields by factors of up to 10.

58 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202350
2022133
2021103
2020135
2019123
2018133