46 research outputs found

    Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

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    Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

    Research on the Brand Building of Airways in China ——Brand Building of Pengda Airlines as an Example

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    面对经济全球化的浪潮,天空开放已经成为世界航空业的必然趋势,市场、资本、政策的壁垒正在逐步被打破,这既是机遇也是挑战。中国民航经过近年来规模的快速增长,已经奠定了世界民航大国的地位,与此同时,由于市场化程度低、产品同质化,民族航空业的国际竞争力仍有待大力提升。 纵观世界民航发展史,不论是新航、英航等行业常青树,还是捷蓝、维珍等行业新星,无不是以自身独特的价值屹立于世界航空之林,受到消费者的青睐和追捧,而这一独特价值的集中表现就是——品牌,品牌是一个企业基业常青的载体和象征。 本文结合先进的品牌理念和科学的管理工具,剖析民航行业发展态势和航空公司经营特征,以鹏达航空公司的品牌建设为例,从鹏航...In the face of economic globalization, the sky opening up, has become an inevitable trend in the global aviation industry, market, capital and policy barriers are gradually being broken, which is both an opportunity and a challenge. The scale of China's civil aviation through the rapid growth in recent years has laid the world's great power status of civil aviation, while the low level of the mark...学位:文学硕士院系专业:新闻传播学院新闻学系_新闻学学号:1052008115316

    Evaluating and Analyzing Click Simulation in Web Search

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    We evaluate and analyze the quality of click models with respect to their ability to simulate users' click behavior. To this end, we propose distribution-based metrics for measuring the quality of click simulation in addition to metrics that directly compare simulated and real clicks. We perform a comparison of widely-used click models in terms of the quality of click simulation and analyze this quality for queries with different frequencies. We find that click models fail to accurately simulate user clicks, especially when simulating sessions with no clicks and sessions with a click on the first position. We also find that click models with higher click prediction performance simulate clicks better than other models

    To the problem about hardening duration of blooming ingot in iron mold

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    There is given the comparative analysis of solution of the problem of blooming ingot solidification in a casting mold by different methods for the purpose of determination of complete solidification duration
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