27,971 research outputs found

    Hadronic Axion Model in Gauge-Mediated Supersymmetry Breaking

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    A simple hadronic axion model is proposed in the framework of gauge-mediated supersymmetry breaking. Dynamics of Peccei-Quinn symmetry breaking is governed by supersymmetry breaking effects and the Peccei-Quinn breaking scale fPQf_{PQ} is inversely proportional to the gravitino mass. The gravitino mass range which corresponds to the axion window fPQ109f_{PQ} \simeq 10^{9} GeV -- 101310^{13} GeV lies in the region predicted by gauge-mediated supersymmetry breaking models. The model is also shown to be cosmologically viable.Comment: 20 pages including seven postscript figures, reviced version to be published in Physics Letters

    Electrochemical performance of a thin film type SOFC on a porous microtubular support

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    This report summarizes electrochemical performances of a thin film type SOFC prepared on a porous microtubular support. The sample was prepared via the co-sintering of YSZ electrolyte and NiO-YSZ anode bilayers on a porous microtubular YSZ support, and then an LSCF-GDC cathode layer was also prepared on the electrolyte film. Evaluations were conducted using impedance analyzer and potentio/galvanostat under a humidified hydrogen flow. Film thickness of the anode layer was controlled by the composition of the anode coating suspension and the coating conditions (coating number and coating speed etc.). Impedance analyses showed that with increasing operation temperature, semi-circle at higher frequency region became small, while semi-circle at lower frequency region weakly depended on the temperature. Electrode activation energy was calculated to be approximately 80 kJ/mol using Arrhenius plot on the semi-circle at higher frequency region.open1133Nsciescopu

    Integration of visual stimuli by the crayfish central nervous system

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    For the crayfish, properties of visually reacting interneurone types in the optic nerve are described on the basis of single-unit analysis. Sustaining fibres show: (a) ‘surround’ inhibition over the whole retina, including the excitatory field; (b) ‘on’ and ‘off’ effects at field boundaries; (c) a dark discharge in deteriorated preparations; (d) an increase in adapted firing rate and response to flashes in an ‘excited state’ of the preparation; (e) increased overall impulse frequency to fast-moving shadows at frequencies of 2-10/sec. which elicit short bursts. Dimming fibres, having mainly reversed properties, show: (a) bursts followed by adaptation to a lower ferquency level of spikes on light dimming; (b) total inhibition by illumination for times proportional to light intensity; (c) responsiveness to quickly moving shadows. 'Jittery’ movement fibres lack directional sensitivity. For them: (a) total illumination and contrast have, within a wide range, no effect on discharges to moving targets; (b) large, dark cards moved at constant speed are seen only near their visual field boundary; (c) the less predictable the movement of a small dark object is, the longer its excitatory effect lasts; (d) responsiveness of field parts exposed is decreased for long durations; (e) no firing is caused by active or passive eye motions. Space-constant fibres show changed location and size of their excitatory fields with eye position. Their potential visual fields below the horizontal plane are unresponsive, due to inhibition caused mainly by statocyst input. Two eye muscle motor fibres, also under statocyst control, are influenced by light on the limited sensory fields of two pairs of identifiable sustaining fibres. The two motor fibres, which innervate antagonistic muscles, are reversely excited and inhibited by these fields

    Parity violating observables in radiative neutrino pair emission from metastable atoms

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    We report on a possibility of measuring parity violating effects in radiative neutrino pair emission from metastable atoms; asymmetric angular distribution of emitted photons from oriented atoms and emergent circular polarization. Their observation, along with the continuous photon energy spectrum which has 6 thresholds, may be interpreted as events being a combined weak and QED process, emission of γνiνj\gamma \nu_i \nu_j in the final state. The method may greatly help to perform neutrino mass spectroscopy using atoms, a systematic determination of the neutrino mass matrix.Comment: 9 pages, 4 figure