Lu J.,Guangxi University |
Lu J.,Guangxi Key Laboratory for Relativistic Astrophysics |
Xing J.-W.,Huazhong University of Science and Technology |
Zou Y.-C.,Huazhong University of Science and Technology |
And 3 more authors.
Research in Astronomy and Astrophysics
The well-known correlation between radio luminosity (LR) and X-ray luminosity (LX), LR/LX ≃ 10-5, holds for a variety of objects, such as active galactic nuclei, Galactic black holes, solar flares and cool stars. Here we extend the relation to gamma-ray bursts (GRBs) and find that the GRBs also obey a similar LR - LX relation, with a slightly different slope of LR ∝ LX1.1. This relation implies that the explosions that occur on different scales may have a common underlying origin. © 2015 National Astronomical Observatories, Chinese Academy of Sciences and IOP Publishing Ltd. Source
Jiang W.,Guangxi University |
Jiang W.,Guangxi Key Laboratory for Relativistic Astrophysics |
Guo J.,Guangxi University |
Cao S.,Guangxi University
Russian Journal of Electrochemistry
La1.8Ti0.2MgNi9–xCox (x = 0, 0.1, 0.3, 0.5) alloys were prepared by magnetic levitation melting under argon atmosphere. The effects of Co substitution on the phase structure and the hydrogen storage properties of the alloys were investigated. The results show that LaNi5 and LaMg2Ni9 phases are contained in all experimental alloys. LaNi3 phase disappears and LaNi2 phase appears as x ≥ 0.1 and x ≥ 0.3, respectively. Electrochemical performances have been improved after Co substitution for Ni, for example, the discharge capacity and the high rate dischargeability (HRD) reach the maximum at x = 0.1, and the optimum cycling stability is obtained at x = 0.5. The positive impact of Co on the hydrogen diffusion rate in bulk enhances the HRD, but to high Co content (x ≥ 0.3), the unsatisfied hydrogen desorption capability brings relative low HRD compared with the alloy electrode at x = 0.1. © 2016, Pleiades Publishing, Ltd. Source
Lin T.,Guangxi University |
Lin T.,Guangxi Key Laboratory for Relativistic Astrophysics |
Qiu Z.R.,Sun Yat Sen University |
Yang J.-R.,National Taiwan University |
And 4 more authors.
This paper reports the transient photoluminescence properties of a typical InGaN/GaN multiple quantum well light emitting diode structure. Two decay processes were found to contribute to the photoluminescence dynamics. Based on the exciton localization model, key factors, transient lifetimes of radiative/nonradiative recombination, were obtained respectively for two decay processes by numerically fitting and separating the mixed photoluminescence efficiencies and photoluminescence decay data, which provide guidance to trace the origins of exciton localization. The origins of slow PL process and fast PL process were reasonably assigned to local compositional fluctuations of indium and thickness variation of InGaN layers, respectively. © 2016 Elsevier B.V. All rights reserved. Source
Wang Y.-Z.,Guangxi University |
Wang Y.-Z.,Guangxi Key Laboratory for Relativistic Astrophysics |
Zhao Y.,University of Florida |
Shao L.,Hebei Normal University |
And 5 more authors.
Strong spectral softening has been revealed in the late X-ray afterglows of some gamma-ray bursts (GRBs). The scenario of X-ray scattering around the circumburst dusty medium has been supported by previous works due to its overall successful prediction of both the temporal and spectral evolution of some X-ray afterglows. To further investigate the observed feature of spectral softening we now systematically search the X-ray afterglows detected by the X-ray telescope aboard Swift and collect 12 GRBs with significant late-time spectral softening. We find that dust scattering could be the dominant radiative mechanism for these X-ray afterglows regarding their temporal and spectral features. For some well-observed bursts with high-quality data, the time-resolved spectra could be well-produced within the scattering scenario by taking into account the X-ray absorption from the circumburst medium. We also find that during spectral softening the power-law index in the high-energy end of the spectra does not vary much. The spectral softening is mainly manifested by the spectral peak energy continually moving to the soft end. © 2016. The American Astronomical Society. All rights reserved. Source
Liang E.-W.,Guangxi University |
Liang E.-W.,Guangxi Key Laboratory for Relativistic Astrophysics |
Liang E.-W.,CAS National Astronomical Observatories |
Lin T.-T.,Guangxi University |
And 9 more authors.
We select a sample of 34 gamma-ray bursts (GRBs) whose Γ0 values are derived with the onset peaks observed in the afterglow light curves (except for GRB 060218, whose Γ0 is estimated with its radio data), and investigate the correlations among Γ0, the isotropic peak luminosity (Liso), and the peak energy (Ep,z) of the νfν spectrum in the cosmological rest frame. An analysis of pair correlations among these observables well confirms the results reported by the previous papers. More interestingly, a tight correlation among Liso, Ep,z, and Γ0 is found from a multiple regression analysis, which takes the form of Liso ∝ Ep,z 1.34 ± 0.14 Γ0 1.32± 0.19 or Ep,z ∝ Liso 0.55 ± 0.06 Γ0 -0.50± 0.17 Nine other GRBs whose Γ0 are derived via the pair production opacity constraint also follow such a correlation. Excluding GRB 060218, the Liso-Ep,z-Γ0 correlation is valid, and it even holds in the jet co-moving frame. However, GRB 060218 deviates the Liso'-Ep' relation of typical GRBs in the jet co-moving frame with 3σ. We argue that the Liso-Ep,z-Γ0 correlation may be more physical than the Liso-Ep,z correlation, since physically the relationship between the observed Liso and Ep,z not only depends on radiation physics, but also depends on the bulk motion of the jet. We explore the possible origins of this correlation and discuss its physical implications for understanding GRB jet composition and radiation mechanisms. © 2015. The American Astronomical Society. All rights reserved. Source