278,036 research outputs found

    Polarity sensitive circuit Patent

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    Electric circuit for reversing direction of current flo

    Circuit switches latching relay in response to signals of different polarity

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    A circuit using one power supply and two storage capacitors, which may be separately discharged in opposite directions through a relay in response to change in polarity of a signal, is described

    Efficacy of laser preionization with a semiconductor source and propene addition

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    It is established that propene is an effective additive instabilising uv preionised CO2 TEA laser discharges: its effect being particularly pronounced with semiconductor-edge preionised lasers where the preionisation levels are shown to be low

    Supporting the assessment, learning and teaching needs of parttime teaching staff

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    Temperature perturbation model of the opto-galvanic effect in CO2-laser discharges

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    A detailed discharge model of the opto-galvanic effect in molecular laser gas mixtures is developed based on the temperature perturbation or discharge cooling mechanism of Smith and Brooks (1979). Excellent agreement between the model and experimental results in CO2 laser gas mixtures is obtained. The model should be applicable to other molecular systems where the OGE is being used for laser stabilisation and as a spectroscopic tool

    Effect of limb darkening on earth radiation incident on a spherical satellite

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    The thermal radiation from the earth incident on a spherical satellite depends on the angular distribution of earth-emitted radiation. An analysis is presented of this dependency, and calculated results are given, based on a published limb-darkening curve for the earth. The curve was determined from Tiros data, and is a statistical average over the entire globe between 75 deg latitude. The computed effect of limb darkening was 1.8 percent at 900 km altitude, 2.5 percent at 500 km altitude, and 3.0 percent at 300 km altitude. Below 300 km, it increased rapidly with decreasing altitude. Discussion is included of various other problems inherent in the use of orbiting spheres and stabilized flat plates to measure the heat radiated from the earth

    Dynamics and star formation activity of CG J1720-67.8 unveiled through integral field spectroscopy and radio observations

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    CG J1720-67.8 is an ultra compact group of several galaxies with a low velocity dispersion, and displaying the hallmarks of mutual interaction and possible tidal dwarf galaxy formation. In hierarchical models, the system is a possible precursor to a massive elliptical galaxy. In this paper, we use new optical integral field spectroscopic and radio observations to investigate the evolutionary status of the group in more detail: global star-formation rates are estimated using Hα\alpha and 1.4 GHz radio continuum measurements; H {\sc i} observations provide an upper limit to the global neutral gas content; optical broadband colours and spectra provide ages and stellar mass estimates for the tidal dwarf candidates; the bidimensional Hα\alpha velocity field is used to trace the kinematics of the group and its members, which are compared with numerical simulations of galaxy encounters. The observations suggest a model in which multiple interactions have occurred, with the latest strong encounter involving at least two major components within the last 200 Myr. Debris from the encounter fuels ongoing star formation at the global level of ∼20\sim20 M⊙_{\odot} yr−1^{-1}, with self-gravity within the tidal tail possibly providing a mechanism to enhance the star formation rate of the tidal dwarf candidates, with bursts of star-formation in clumps of mass ∼2×107\sim2\times 10^7 M⊙_{\odot} appearing within the last 10 Myr. The amount of time required for final merging of all group components remains uncertain.Comment: 22 pages, 16 figures. Accepted for publication in MNRA
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