Numerical Analysis of Space Effect on the Pile-Anchor Bracing Deep Foundation Pit

Volume 8 Issue 1 (January 201

Multistage Random Growing Small-World Networks with Power-law degree Distribution

In this paper, a simply rule that generates scale-free networks with very large clustering coefficient and very small average distance is presented. These networks are called {\bf Multistage Random Growing Networks}(MRGN) as the adding process of a new node to the network is composed of two stages. The analytic results of power-law exponent $\gamma=3$ and clustering coefficient $C=0.81$ are obtained, which agree with the simulation results approximately. In addition, the average distance of the networks increases logarithmical with the number of the network vertices is proved analytically. Since many real-life networks are both scale-free and small-world networks, MRGN may perform well in mimicking reality.Comment: 3 figures, 4 page

Reanalysis of the X-ray burst associated FRB 200428 with Insight-HXMT observations

A double-peak X-ray burst from the Galactic magnetar SGR J1935+2154 was discovered as associated with the two radio pulses of FRB 200428 separated by 28.97+-0.02 ms. Precise measurements of the timing and spectral properties of the X-ray bursts are helpful for understanding the physical origin of fast radio bursts (FRBs). In this paper, we have reconstructed some information about the hard X-ray events, which were lost because the High Energy X-ray Telescope (HE) onboard the Insight-HXMT mission was saturated by this extremely bright burst, and used the information to improve the temporal and spectral analyses of the X-ray burst. The arrival times of the two X-ray peaks by fitting the new Insight-HXMT/HE lightcurve with multi-Gaussian profiles are 2.77+-0.45 ms and 34.30+-0.56 ms after the first peak of FRB 200428, respectively, while these two parameters are 2.57+-0.52 ms and 32.5+-1.4 ms if the fitting profile is a fast rise and exponential decay function. The spectrum of the two X-ray peaks could be described by a cutoff power-law with cutoff energy ~60 keV and photon index ~1.4, the latter is softer than that of the underlying bright and broader X-ray burst when the two X-ray peaks appeared.Comment: 11 pages, 7 figure

Relation of cyclotron resonant energy and luminosity in a strongly magnetized neutron star GRO J1008-57 observed by Insight-HXMT

Cyclotron line scattering features are detected in a few tens of X-ray pulsars (XRPs) and used as direct indicators of a strong magnetic field at the surface of accreting neutron stars (NSs). In a few cases, cyclotron lines are known to be variable with accretion luminosity of XRPs. It is accepted that the observed variations of cyclotron line scattering features are related to variations of geometry and dynamics of accretion flow above the magnetic poles of a NS. A positive correlation between the line centroid energy and luminosity is typical for sub-critical XRPs, where the accretion results in hot spots at the magnetic poles. The negative correlation was proposed to be a specific feature of bright super-critical XRPs, where radiation pressure supports accretion columns above the stellar surface. Cyclotron line in spectra of Be-transient X-ray pulsar GRO J1008-57 is detected at energies from $\sim 75 -90$ keV, the highest observed energy of cyclotron line feature in XRPs. We report the peculiar relation of cyclotron line centroid energies with luminosity in GRO J1008-57 during the Type II outburst in August 2017 observed by Insight-HXMT. The cyclotron line energy was detected to be negatively correlated with the luminosity at 3.2\times 10^{37}\,\ergs, and positively correlated at L\gtrsim 5\times 10^{37}\,\ergs. We speculate that the observed peculiar behavior of a cyclotron line would be due to variations of accretion channel geometry.Comment: 9 pages. 5 figures, 2 tables, accept for publication in Ap