12,887 research outputs found

    GRB/GW association: Long-short GRB candidates, time-lag, measuring gravitational wave velocity and testing Einstein's equivalence principle

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    Short-duration gamma-ray bursts (SGRBs) are widely believed to be powered by the mergers of compact binaries, such as binary neutron stars or possibly neutron star-black hole binaries. Though the prospect of detecting SGRBs with gravitational wave (GW) signals by the advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)/VIRGO network is promising, no known SGRB has been found within the expected advanced LIGO/VIRGO sensitivity range for binary neutron star systems. We find, however, that the two long-short GRBs (GRB 060505 and GRB 060614) may be within the horizon of advanced GW detectors. In the upcoming era of GW astronomy, the merger origin of some long-short GRBs, as favored by the macronova signature displayed in GRB 060614, can be unambiguously tested. The model-dependent time lags between the merger and the onset of the prompt emission of the GRB are estimated. The comparison of such time lags between model predictions and the real data expected in the era of the GW astronomy would be helpful in revealing the physical processes taking place at the central engine (including the launch of the relativistic outflow, the emergence of the outflow from the dense material ejected during the merger, and the radiation of gamma rays). We also show that the speed of GWs, with or without a simultaneous test of Einstein's equivalence principle, can be directly measured to an accuracy of ∼3×10−8 cm s−1\sim 3\times 10^{-8}~{\rm cm~s^{-1}} or even better in the advanced LIGO/VIRGO era. The Astrophysical Journal, VolumeComment: 12 pages, 3 figures, published in The Astrophysical Journa

    Modeling of Electrocardiograph Telediagnosing System Based on Petri Net

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    AbstractThis paper analyzed the characteristics of the electrocardiograph telediagnosing system. Firstly, we introduce the system and Petri nets. Secondly, we built a topological diagram of this system. Then we use Petri nets to show the physical process of this system. Finally, we verified the model of the electrocardiograph telediagnosing system. With the help of model based on Petri nets, we analyzed the system performance and feasibility

    Motion Analysis of PLET during the Setting-Down Process

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    The design analysis of Subsea PLET should consider various cases, including in-place analysis, lifting analysis, setting down analysis and so on. The size and vessel space should be checked in the structural design, and the fishing protection function should also be covered. The accurate setting-down process is the prerequisite for the successful construction of the subsea project. Therefore, it is necessary to simulate the various conditions included in the setting down process. Based on practical YC13-1 project and subsea environment condition, a special type of subsea PLET is designed for the pipe rehabilitation. Theoretical study is performed to discuss the load and Fluent software is used to simulate the problems encountered in the setting-down process. Comparison on the calculation results with ROV condition and without ROV condition, it indicates the effective suppression of the movement of PLET with ROV tractive action. The study can be a good reference and guidance for the design and construction of South China Sea oil and gas field project
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