28 research outputs found

    Weinberg like sum rules revisited

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    The generalized Weinberg sum rules containing the difference of isovector vector and axial-vector spectral functions saturated by both finite and infinite number of narrow resonances are considered. We summarize the status of these sum rules and analyze their overall agreement with phenomenological Lagrangians, low-energy relations, parity doubling, hadron string models, and experimental data.Comment: 31 pages, noticed misprints are corrected, references are added, and other minor corrections are mad

    Observation of parametric X-rays produced by 400 GeV/c protons in bent crystals

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    Spectral maxima of parametric X-ray radiation (PXR) produced by 400 GeV/c protons in bent silicon crystals aligned with the beam have been observed in an experiment at the H8 external beam of the CERN SPS. The total yield of PXR photons was about 10-6 per proton. Agreement between calculations and the experimental data shows that the PXR kinematic theory is valid for bent crystals with sufficiently small curvature as used in the experiment. The intensity of PXR emitted from halo protons in a bent crystal used as a primary collimator in a circular accelerator may be considered as a possible tool to control its crystal structure, which is slowly damaged because of irradiation. The intensity distribution of PXR peaks depends on the crystal thickness intersected by the beam, which changes for different orientations of a crystal collimator. This dependence may be used to control crystal collimator alignment by analyzing PXR spectra produced by halo protons.peer-reviewe

    The Influence of Political Connection and Institutions to the Performance and Bank Loans of Private Listed Companies

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    我国有着不同于西方发达国家的制度背景和政治制度,政府对市场的管制力度较大,上市公司的高管具有一定的政治背景,其中国有企业本身大股东的政府背景性质,其政治关联很可能是与生俱来的,而民营企业政治关联的形成则具有主动性。改革开放以来,民营经济不断发展壮大,己成为我国经济增长的主要推动力量,因此,研究政治关联对民营公司的影响这一问题在中国更具有现实启发意义。 本文以民营上市公司的高级管理人员是否是前任或现任的政府官员、人大代表或政协委员来衡量公司是否具有政治关联,选取2004年—2008年中国沪深两市所有A股民营上市公司为样本,实证研究了政治关联与制度环境对民营上市公司经营绩效和银行贷款的影响。研究...Chinese current institution and political system are different from the Western developed countries. Under this system, many executives of private listed companies are relevant to politics. Therefore the study of political influence of private companies related to this issue in China is more realistic instructive. This paper focuses on whether the company has the political connection, which measu...学位:管理学硕士院系专业:管理学院财务学系_财务学学号:1762007115174

    On Regular Language Factorisation: A Complete Solution for Unary Case

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    These are the papers for the poster talks to be given at the Eighth International Conference on Developments in Language Theory (DLT’04) to be held at Auckland, New Zeland on December 13–17, 2004. The conference is jointly organized by Massey Universty at Albany and the CDMTCS (New Zealand). The conference, organised under the auspicies of the European Association for Theoretical Computer Science (EATCS), is supported by the New Zealand Roya

    High-efficiency deflection of high-energy negative particles through axial channeling in a bent crystal

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    Deflection due to axial channeling in a silicon crystal bent along the [111] axis was observed for 150 GeV/c negative particles, mainly π− mesons, at one of the secondary beams of the CERN SPS. The whole beam was deflected to one side with the efficiency of about 90% and with the peak position at the bend crystal angle α=43 μrad. The deflection occurs mainly due to doughnut scattering of above-barrier particles by the atomic strings of the crystal. However, due to a high probability of particle recapture into bound states with the atomic strings their contribution to the deflection should be about 15% for our case according to simulation results
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