92,881 research outputs found
Rankine-Hugoniot Relations in Relativistic Combustion Waves
As a foundational element describing relativistic reacting waves of relevance
to astrophysical phenomena, the Rankine-Hugoniot relations classifying the
various propagation modes of detonation and deflagration are analyzed in the
relativistic regime, with the results properly degenerating to the
non-relativistic and highlyrelativistic limits. The existence of
negative-pressure downstream flows is noted for relativistic shocks, which
could be of interest in the understanding of the nature of dark energy. Entropy
analysis for relativistic shock waves are also performed for relativistic
fluids with different equations of state (EoS), denoting the existence of
rarefaction shocks in fluids with adiabatic index \Gamma < 1 in their EoS. The
analysis further shows that weak detonations and strong deflagrations, which
are rare phenomena in terrestrial environments, are expected to exist more
commonly in astrophysical systems because of the various endothermic reactions
present therein. Additional topics of relevance to astrophysical phenomena are
also discussed.Comment: 34 pages, 9 figures, accepted for publication in Ap
Magnetic reconnection detonation in supernova remnants
As a key process that refreshes the interstellar medium, the dynamics and
radiative properties of the supernova remnant (SNR) expansion front not only
reflect the physical environment of the old interstellar medium (ISM)
surrounding the supernova, but they also provide information about the
refreshed ISM. However the expansion dynamics of SNRs cannot be simply
explained by the conventional law of spherical shock wave propagation; on the
other hand, the high energy radiation requires an additional electron
acceleration mechanism in the shock front beyond thermal collision. We consider
herein the detonation wave description of the SNR expansion, in which magnetic
reconnection follows the shock front and transfers the SNR magnetic field
energy to both fluid thermal energy and particle kinetic energy. The structure
of the magnetic reconnection detonation (MRD) is identified based on scaling
analysis in this paper. By applying the MRD description of the SNR expansion
shock to the example of the Crab Nebula, this paper shows that the MRD
description can explain both the accelerative expansion of the nebula as well
as the origin of the luminous expanding shell.Comment: Accepted for publication in Ap
Detailed comparison of Milky Way models based on stellar population synthesis and SDSS star counts at the north Galactic pole
We test the ability of the TRILEGAL and Besancon models to reproduce the CMD
of SDSS data at the north Galactic pole (NGP). We show that a Hess diagram
analysis of colour-magnitude diagrams is much more powerful than luminosity
functions (LFs) in determining the Milky Way structure. We derive a
best-fitting TRILEGAL model to simulate the NGP field in the (g-r, g) CMD of
SDSS filters via Hess diagrams. For the Besancon model, we simulate the LFs and
Hess diagrams in all SDSS filters. We use a chi2 analysis and determine the
median of the relative deviations in the Hess diagrams to quantify the quality
of the fits by the TRILEGAL models and the Besancon model in comparison and
compare this with the Just-Jahreiss model. The input isochrones in the
colour-absolute magnitude diagrams of the thick disc and halo are tested via
the observed fiducial isochrones of globular clusters (GCs). We find that the
default parameter set lacking a thick disc component gives the best
representation of the LF in TRILEGAL. The Hess diagram reveals that a
metal-poor thick disc is needed. In the Hess diagram, the median relative
deviation of the TRILEGAL model and the SDSS data amounts to 25 percent,
whereas for the Just-Jahreiss model the deviation is only 5.6 percent. The
isochrone analysis shows that the representation of the MS of (at least
metal-poor) stellar populations in the SDSS system is reliable. In contrast,
the RGBs fail to match the observed fiducial sequences of GCs. The Besancon
model shows a similar median relative deviation of 26 percent in (g-r, g). In
the u band, the deviations are larger. There are significant offsets between
the isochrone set used in the Besancon model and the observed fiducial
isochrones. In contrast to Hess diagrams, LFs are insensitive to the detailed
structure of the Milky Way components due to the extended spatial distribution
along the line of sight.Comment: 21 pages, 17 figures and 5 tables. Accepted by publication of A&
Optimal Controlled Teleportation
We give the analytic expressions of maximal probabilities of successfully
controlled teleportating an unknown qubit via every kind of tripartite states.
Besides, another kind of localizable entanglement is also determined.
Furthermore, we give the sufficient and necessary condition that a three-qubit
state can be collapsed to an EPR pair by a measurement on one qubit, and
characterize the three-qubit states that can be used as quantum channel for
controlled teleporting a qubit of unknown information with unit probability and
with unit fidelity.Comment: 4 page
Innovation Institution and Spatial Transfer of Energy Industry: The Case of Jiangsu Province, China
This study aims to explore the effect of innovation institution on spatial transfer of energy industry in Jiangsu, China. We focus on the disparity of innovation and energy industry, and analyze the spatial transfer difference in different types of energy industry, rather than view energy industry as a whole. The study demonstrates the spatial change of energy industry at regional level and maps the spatial pattern at city level. The study chooses intellectual property rights (IPRs) protection intensity, authorization patents and local research and development (R&D) investment as the proxy of innovation. Using official data and employing panel fixed-effect model at city-industry level, we conclude (a) innovation abilities significantly influence the spatial transfer of energy industry in Jiangsu. Especially, due to the different time, IPRs protection, patent counts, and R&D investment have different effects on different regions in Jiangsu; (b) 2010 is an important turning point for energy industry development in Jiangsu, and after 2010, the energy industry begins to shift to the middle and northern Jiangsu, whereas the spatial pattern of energy industry in coastal cities is basically unchanged; (c) there is a great difference between the regions in Jiangsu Province, and industrial upgrading has not been achieved in northern Jiangsu
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