2,621 research outputs found

    Swift Observations of the Be/X-ray Transient System 1A 1118-615

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    We report results of Swift observations for the high mass Be/X-ray binary system 1A 1118-615, during an outburst stage in January, 2009 and at a flaring stage in March, 2009. Using the epoch-folding method, we successfully detected a pulsed period of 407.69(2) sec in the outburst of January and of 407.26(1) sec after the flare detection in March. We find that the spectral detection for the source during outburst can be described by a blackbody model with a high temperature (kT ~ 1-3 keV) and a small radius (R ~ 1 km), indicating that the emission results from the polar cap of the neutron star. On the other hand, the spectra obtained after the outburst can further be described by adding an additional component with a lower temperature (kT ~ 0.1-0.2 keV) and a larger emission radius (R ~ 10-500 km), which indicates the emission from around the inner region of an accretion disk. We find that the thermal emission from the hot spot of the accreting neutron star dominates the radiation in outburst; the existence of both this X-ray contribution and the additional soft component suggest that the polar cap and the accretion disk emission might co-exist after the outburst. Because the two-blackbody signature at the flaring stage is a unique feature of 1A 1118-615, our spectral results may provide a new insight to interpret the X-ray emission for the accreting neutron star. The time separation between the three main outbursts of this system is ~17 years and it might be related to the orbital period. We derive and discuss the associated physical properties by assuming the elongated orbit for this specific Be/X-ray transient.Comment: 9 pages, 3 figures and 4 tables; accepted by MNRA

    Development of a Piezoelectric Vacuum Sensing Component for a Wide Pressure Range

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    In this study, we develop a clamped-clamped beam-type piezoelectric vacuum pressure sensing element. The clamped-clamped piezoelectric beam is composed of a PZT layer and a copper substrate. A pair of electrodes is set near each end. An input voltage is applied to a pair of electrodes to vibrate the piezoelectric beam, and the output voltage is measured at the other pair. Because the viscous forces on the piezoelectric beam vary at different air pressures, the vibration of the beam depends on the vacuum pressure. The developed pressure sensor can sense a wide range of pressure, from 6.5 × 10(-6) to 760 Torr. The experimental results showed that the output voltage is inversely proportional to the gas damping ratio, and thus, the vacuum pressure was estimated from the output voltage

    Mean-variance model with fuzzy random data

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    This paper recommends discourse feeling acknowledgment from discourse signal dependent on highlights examination and PNN-classifier. The arrangement of acknowledgment incorporates discovery of discourse feelings, extraction and determination of highlights, lastly characterization. These highlights are valued to segregate the greatest number of tests precisely and the PNN classifier dependent on discriminant investigation is utilized to characterize the six distinctive articulations. The reproduced outcomes will be indicated that the channel occupied component extortion with utilized distribution presents much better exactness with less algorithmic unpredictability than other discourse feeling articulation acknowledgment draws near

    Influence of migration policy risk on international market segmentation: analysis of housing and rental markets in the euro area

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    This paper aims to discuss the influence of migration policy risk on market segmentation of housing and rental markets in the Euro Area. Policy risk is represented by the Migration Policy Uncertainty Index (MPUI) and Migration Fear Index (MFI) of Germany and the United Kingdom; in this study, whether these indexes influence the interaction between the housing and rental markets of the two countries and euro-area countries was examined. The empirical results showed that the influence of the United Kingdom’s migration policy risk on the euro-area countries is higher than that of Germany. The United Kingdom’s MPUI and MFI significantly contribute to the influence of the United Kingdom’s housing market on other markets except for Belgium and Spain. Compared with housing market connectedness, the rental market connectedness is less influenced by migration policy risk and migration fear. This may be because variables related to short-term residence policies influence the rental market. The high policy risk is more likely to influence decisions related to long-term house purchase, but not those related to short-term residence. Finally, this study found that the higher the uncertainty of the migration policies of the United Kingdom and Germany is, the higher the house market segmentation is

    The X-ray Properties of the Energetic Pulsar PSR J1838-0655

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    We present and interpret several new X-ray features of the X-ray pulsar PSR J1838-0655. The X-ray data are obtained from the archival data of CHANDRA, RXTE}, and SUZAKU. We combine all these X-ray data and fit the spectra with different models. We find that the joint spectra are difficult to fit with a single power law; a broken power-law model with a break at around 6.5 keV can improve the fit significantly. The photon index changes from Γ\Gamma = 1.0 (below 6.5 keV) to Γ\Gamma = 1.5 (above 6.5 keV); this indicates a softer spectral behaviour at hard X-rays. The X-ray flux at 2-20 keV is found to be 1.6x10^{-11} ergs cm^{-2} s^{-1}. The conversion efficiency from the spin-down luminosity is ~ 0.9% at 0.8-10 keV, which is much higher than that (~ 10^{-3}% - 10^{-4}%) of the pulsars that show similar timing properties. We discuss non-thermal radiation mechanisms for the observed high X-ray conversion efficiency and find that emission from the magnetosphere of a greatly inclined rotator is the most favorable interpretation for the conversion rate and the pulse profiles at X-ray bands. A line feature close to 6.65 keV is also detected in the spectra of SUZAKU/XIS; it might be the Kα_\alpha emission of highly ionised Fe surrounding the pulsar.Comment: 8 pages, 6 figures and 1 tabl
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