28,613 research outputs found

    Canopus detector including automotive gain control of photomultiplier tube Patent

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    Photomultiplier detector of Canopus for spacecraft attitude contro

    Surface-gravity determinations for main-sequence B stars

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    Astronomical models for computing surface gravity of B stars from hydrogen line equivalent width

    Radiological health risks to astronauts from space activities and medical procedures

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    Radiation protection standards for space activities differ substantially from those applied to terrestrial working situations. The levels of radiation and subsequent hazards to which space workers are exposed are quite unlike anything found on Earth. The new more highly refined system of risk management involves assessing the risk to each space worker from all sources of radiation (occupational and non-occupational) at the organ level. The risk coefficients were applied to previous space and medical exposures (diagnostic x ray and nuclear medicine procedures) in order to estimate the radiation-induced lifetime cancer incidence and mortality risk. At present, the risk from medical procedures when compared to space activities is 14 times higher for cancer incidence and 13 times higher for cancer mortality; however, this will change as the per capita dose during Space Station Freedom and interplanetary missions increases and more is known about the risks from exposure to high-LET radiation

    Evaluation of bistable systems versus matched filters in detecting bipolar pulse signals

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    This paper presents a thorough evaluation of a bistable system versus a matched filter in detecting bipolar pulse signals. The detectability of the bistable system can be optimized by adding noise, i.e. the stochastic resonance (SR) phenomenon. This SR effect is also demonstrated by approximate statistical detection theory of the bistable system and corresponding numerical simulations. Furthermore, the performance comparison results between the bistable system and the matched filter show that (a) the bistable system is more robust than the matched filter in detecting signals with disturbed pulse rates, and (b) the bistable system approaches the performance of the matched filter in detecting unknown arrival times of received signals, with an especially better computational efficiency. These significant results verify the potential applicability of the bistable system in signal detection field.Comment: 15 pages, 9 figures, MikTex v2.

    Preliminary results of the University of California X-ray experiment on the OSO-3

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    Cosmic and solar X ray data obtained by Orbiting Solar Observatory /OSO-3

    The Upper Limit Solar Gamma-ray Spectrum to 10 Mev

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    Balloon flight data on upper limit solar gamma ray spectrum from quiet su

    Hard X-ray imaging facility for space shuttle: A scientific and conceptual engineering study

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    A shuttle-accommodated instrument for imaging hard X-rays in the study of nonthermal particles and high temperature particles in various solar and cosmic phenomena was defined and its feasibility demonstrated. The imaging system configuration is described as well as the electronics, aspect systems, mechanical and thermal properties and the ground support equipment
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