303 research outputs found

    Electroweak axion string and superconductivity

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    We study the axion strings with the electroweak gauge flux in the DFSZ axion model and show that these strings, called the electroweak axion strings, can exhibit superconductivity without fermionic zero modes. We construct three types of electroweak axion string solutions. Among them, the string with WW-flux can be lightest in some parameter space, which leads to a stable superconducting cosmic string. We also show that a large electric current can flow along the string due to the Peccei-Quinn scale much higher than the electroweak scale. This large current induces a net attractive force between the axion strings with the same topological charge, which opens a novel possibility that the axion strings form Y-junctions in the early universe.Comment: 35 pages, 8 figures; v3: published versio

    Quantum current dissipation in superconducting strings and vortons

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    In this work, the current stability is discussed for cosmic strings with the bosonic superconductivity. A non-vanishing curvature of string generally induce the quantum instability of the current-carrying particle. Its decay rates are explored for various types of model parameters, curved string shapes, and decay processes. As a cosmological application, the stability is examined for superconducting strings in the string network and also for cosmic vortons by evaluating their cosmological evolution. The zero mode and hence the vorton cannot be stable in various cases, e.g., with a hierarchy between the current-carrying particle mass off the string and the string tension or with sizable couplings of the current-carrying particle to light species such as the Standard Model particles.Comment: 42 pages, 14 figures, 1 tabl

    冠動脈高度石灰化病変に対するスコアリングバルーンラクロスNon-Slip Elementを用いた冠動脈形成術-光干渉断層法による有用性の評価

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    Percutaneous coronary intervention (PCI) for heavily calcified lesions is challenging because these lesions are resistant to balloon dilatation and stenting. Lacrosse non-slip element (NSE) may have the potential to dilate heavily calcified lesions. We aimed to investigate predictors of successful lesion modification using Lacrosse NSE angioplasty via optical coherence tomography (OCT)-guided PCI. We investigated 32 patients with severe target lesion calcification treated with OCT-guided PCI. Successful lesion modification was defined as the complete fracture of calcification after Lacrosse NSE angioplasty. Before PCI, 172 segments with calcification were identified. After pre-dilatation using Lacrosse NSE, successful lesion modification was achieved in 117 segments (68.0%). Calcification was significantly thinner in successfully disrupted segments than in non-disrupted segments (p < 0.001). Calcification angle tended to be larger in disrupted than in non-disrupted segments (p = 0.08). Convex types were less frequently observed in disrupted than in non-disrupted segments (p < 0.001). At minimal lumen area sites, 26 segments (81.3%) were successfully modified. Similar to the overall results, the disrupted group had significantly thinner calcification than the non-disrupted group (p < 0.001). The angle of the calcified plaque was similar between the 2 groups (p = 0.39). Convex-type calcifications were less frequently observed in the disrupted group than in the non-disrupted group (p = 0.05). Receiver-operating characteristic curve analysis showed that calcification thickness < 565 μm was the best predictor of completely disrupted calcification. The thickness and shape of calcifications were predictors of successful lesion modification after Lacrosse NSE angioplasty.博士(医学)・乙第1426号・平成31年3月15日© Japanese Association of Cardiovascular Intervention and Therapeutics 2018This is a post-peer-review, pre-copyedit version of an article published in Cardiovascular intervention and therapeutics. The final authenticated version is available online at: http://dx.doi.org/10.1007/s12928-018-0553-6

    Optical trapping with structured light : a review

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    Funding: This work was supported by the National Natural Science Foundation of China (11874102 and 61975047), the Sichuan Province Science and Technology Support Program (2020JDRC0006), and the Fundamental Research Funds for the Central Universities (ZYGX2019J102). M.C. and Y.A. thank the UK Engineering and Physical Sciences Research Council for funding.Optical trapping describes the interaction between light and matter to manipulate micro-objects through momentum transfer. In the case of 3D trapping with a single beam, this is termed optical tweezers. Optical tweezers are a powerful and noninvasive tool for manipulating small objects, and have become indispensable in many fields, including physics, biology, soft condensed matter, among others. In the early days, optical trapping was typically accomplished with a single Gaussian beam. In recent years, we have witnessed rapid progress in the use of structured light beams with customized phase, amplitude, and polarization in optical trapping. Unusual beam properties, such as phase singularities on-axis and propagation invariant nature, have opened up novel capabilities to the study of micromanipulation in liquid, air, and vacuum. We summarize the recent advances in the field of optical trapping using structured light beams.Publisher PDFPeer reviewe

    Рациональные применения газотермического напыления в металлургии

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    Power Symposium, 2008. NAPS '08. 40th North American, University of Calgary, Calgary, Canada, Sept 28th to 30th, 2008This paper uses hybrid dynamical systems as a mathematical model for cascading outages in a power system. Hybrid dynamical systems can combine families of flows describing swing dynamics of generators with switching rules describing protection control mechanisms. We refer to data observed in a cascading outage in the September 2003 blackout in Italy and show a hybrid dynamical system by which propagation of outages reproduced is consistent with the data
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