8,993 research outputs found

    Jet-dominated quiescent state in black hole X-ray binaries: the cases of A0620--00 and XTE J1118+480

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    The radiative mechanism of the black hole X-ray transients (BHXTs) in their quiescent states (defined as the 2-10 keV X-ray luminosity 1034ergs1\le 10^{34}{\rm \,erg\,s^{-1}}) remains unclear. In this work, we investigate the quasi-simultaneous quiescent state spectrum (including radio, infrared, optical, ultraviolet and X-ray) of two BHXTs, A0620--00 and XTE J1118+480. We find that, these two sources can be well described by a coupled accretion -- jet model. More specifically, most of the emission (radio up-to infrared, and the X-ray waveband) comes from the collimated relativistic jet. Emission from hot accretion flow is totally insignificant, and it can only be observed in mid-infrared (the synchrotron peak). Emission from the outer cold disc is only evident in UV band. These results are consistent with our previous investigation on the quiescent state of V404 Cyg, and confirm that the quiescent state is jet-dominated.Comment: 11 pages, 1 figure, accepted for publication in Research in Astronomy and Astrophysic

    BCR algorithm and the T(b)T(b) theorem

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    We show using the Beylkin-Coifman-Rokhlin algorithm in the Haar basis that any singular integral operator can be written as the sum of a bounded operator on LpL^p, 1<p<1<p<\infty, and of a perfect dyadic singular integral operator. This allows to deduce a local T(b)T(b) theorem for singular integral operators from the one for perfect dyadic singular integral operators obtained by Hofmann, Muscalu, Thiele, Tao and the first author.Comment: Change of title. New abstract and new introductio

    Estimate for the 0++0^{++} glueball mass in QCD

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    We obtain accurate result for the lightest glueball mass of QCD in 3 dimensions from lattice Hamiltonian field theory. Using the dimensional reduction argument, a good approximation for confining theories, we suggest that the 0++0^{++} glueball mass in 3+1 dimensional QCD be about 1.711.71 GeV.Comment: 10 Latex page

    Void Generation Between Shell and Charge ofWarhead under the Projection Load

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    In the process of projecting, the coupled property of warhead shell and charge is an  important issueof the launching safety study. To maintain charge in close contact with the shell is one of the requirementsfor quality. For solid-liquid mixed charge , its tensile strength is very small, the dynamic response characteristicbetween warhead shell and charge make it possible to form instantaneous void between the shell and charge.his paper studies the impact of factors of instantaneous void and its development law by numerical simulation.This work lays foundation for warhead charge quality control and projection safety.Defence Science Journal, 2008, 58(6), pp.715-720, DOI:http://dx.doi.org/10.14429/dsj.58.169

    Self as method: thinking through China and the world

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    Self as Method

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    Despite China’s rise to the status of global power, many Chinese youths are anxious about their personal future, in large measure because the rapid changes have left them feeling adrift. This book, available in open access, provides a manifesto of intellectual activism that counsels China’s young people to think by themselves and for themselves. Consisting of three conversations between Xiang Biao, a social anthropologist, and Wu Qi, a rising journalist, the book probes how China has reached its current stage and how young people can make changes. The conversations touch on issues of mobility, education, family, relations between the self and the authority, centers and margins, China, and the world. The Chinese version was named the “most impactful book of 2021” by Douban, China’s premier website for rating books, films, and music. The English version is translated by David Ownby, who also penned an introduction
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