6,544 research outputs found

    r-Process Nucleosynthesis in Shocked Surface Layers of O-Ne-Mg Cores

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    We demonstrate that rapid expansion of the shocked surface layers of an O-Ne-Mg core following its collapse can result in r-process nucleosynthesis. As the supernova shock accelerates through these layers, it makes them expand so rapidly that free nucleons remain in disequilibrium with alpha-particles throughout most of the expansion. This allows heavy r-process isotopes including the actinides to form in spite of the very low initial neutron excess of the matter. We estimate that yields of heavy r-process nuclei from this site may be sufficient to explain the Galactic inventory of these isotopes.Comment: 11 pages, 1 figure, to appear in the Astrophysical Journal Letter

    Editorial: Security of cloud service for the manufacturing industry

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    With the rapid development of the industrial Internet, cloud service-based manufacturing has emerged as a next generation manufacturing paradigm that has potential to revolutionize the manufacturing industry. It is foreseeable that cloud services will be popular in the next generation manufacturing industry. In recent years, more and more manufacturing companies have recognized the benefits of cloud service and have developed cloud-based manufacturing models. However, the security problems need to be researched and solved for the cloud services in the manufacturing industry, especially the data security issues are important, and restrict the cloud application in the manufacturing industry. Regarding the security of data, some people believe that when data are stored in the cloud, manufacturing companies lose control of the data. The manufacturing companies focus on how to secure the data from the top-level management and how to minimize the security risks, such as those caused by data security or service migration challenges. The manufacturing companies select the reliable cloud service while consider function and budget feasibility. How to ensure security in cloud service for the manufacturing industry has become a topic of increasing interest for both academic researchers and developers from the industry. This special issue addresses this emerging and fast developing research area on cloud security in manufacturing industry. The summary of these papers is as follows. [...

    Chiral Condensates in Quark and nuclear Matter

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    We present a novel treatment for calculating the in-medium quark condensates. The advantage of this approach is that one does not need to make further assumptions on the derivatives of model parameters with respect to the quark current mass. The normally accepted model-independent result in nuclear matter is naturally reproduced. The change of the quark condensate induced by interactions depends on the incompressibility of nuclear matter. When it is greater than 260 MeV, the density at which the condensate vanishes is higher than that from the linear extrapolation. For the chiral condensate in quark matter, a similar model-independent linear behavior is found at lower densities, which means that the decreasing speed of the condensate in quark matter is merely half of that in nuclear matter if the pion-nucleon sigma commutator is six times the average current mass of u and d quarks. The modification due to QCD-like interactions is found to slow the decreasing speed of the condensate, compared with the linear extrapolation.Comment: 12 pages, 7 figures, revtex4 styl
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