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Influence of the Randomness of Longitudinal Resistance of Ballast Bed on Track-Bridge Interaction
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作者 weiwu dai Yunfei Zhang +1 位作者 Bowen Liu Kaize Xie 《Engineering(科研)》 2023年第11期729-741,共13页
To get the influence of the randomness of longitudinal resistance of ballast bed (LRBB) on track-bridge interaction, the statistical law of LRBB was studied with existing test data and the Shapiro-Wilk test. Based on ... To get the influence of the randomness of longitudinal resistance of ballast bed (LRBB) on track-bridge interaction, the statistical law of LRBB was studied with existing test data and the Shapiro-Wilk test. Based on the principle of track-bridge interaction, a rail-sleeper-bridge-pier integrated simulation model that could consider the randomness of LRBB was established. Taking a continuous beam bridge for the heavy-haul railway as an example, the effect of the randomness of LRBB on the mechanical behavior of continuous welded rail (CWR) on bridges under typical conditions was carefully examined with a random sampling method and the simulation model. The results show that the LRBB corresponding sleeper displacement of 2 mm obeys a normal distribution. When the randomness of LRBB is considered, the amplitudes of rail expansion force, rail bending force, rail braking force and rail broken gap all follow normal distribution. As the standard deviations of the four indexes are small, which indicates the randomness of LRBB has little effect on track-bridge interaction. The distributions of the four indexes make it possible to design CWR on bridges with the limit state method. 展开更多
关键词 Continuous Welded Rail Track-Bridge Interaction Longitudinal Resistance of Ballast Bed Normal Distribution
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基于SRAP标记分析的雄性榧树及榧树物种的遗传多样性 被引量:1
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作者 刘浩凯 张辉 +3 位作者 陈文充 喻卫武 戴文圣 曾燕如 《分子植物育种》 CAS 北大核心 2021年第12期4153-4158,共6页
雌雄异株天然杂交的榧树(Torreya grandis Fort. ex Lindl)存在着丰富的自然变异,具有巨大的选育潜力,自然界也不乏与榧树优良自然变异类型经无性繁殖培育而成的栽培类型香榧(T. grandis‘Merrilli’)相媲美的优良种质。但由于历史的原... 雌雄异株天然杂交的榧树(Torreya grandis Fort. ex Lindl)存在着丰富的自然变异,具有巨大的选育潜力,自然界也不乏与榧树优良自然变异类型经无性繁殖培育而成的栽培类型香榧(T. grandis‘Merrilli’)相媲美的优良种质。但由于历史的原因及香榧产业的发展,榧树的遗传多样性受到了一定的影响。本研究在已有雌性榧树研究的基础上,采用SRAP标记对雌性榧树相同采样地的雄性榧树居群进行分析,并整合雌雄榧树居群的标记分析结果,研究了榧树物种水平的遗传多样性。结果表明,雄性榧树居群平均PPL为63.67%,等位基因数(Na)为1.636 7,有效等位基因数(Ne)为1.381 3,Nei's基因多样性(H)为0.221 8,Shannon信息指数(I)为0.331 1,说明雄性榧树存在较为丰富的遗传多样性,且变异(81.48%)主要存在于居群内个体间;与雌性榧树遗传参数相比,雄性榧树的相关遗传参数均不如雌株;就物种水平而言,榧树丰富的遗传多样性来源于雄、雌榧树共同的作用。基于研究结果提出要注重保护榧树尤其是雄性榧树的遗传多样性,同时建议基于个体的优良表现开展优株选择。 展开更多
关键词 榧树(Torreya grandis) SRAP 遗传多样性
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