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公路网节点层次划分方法 被引量:4
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作者 劳潮惠 吴群琪 王芳 《交通运输工程学报》 EI CSCD 北大核心 2013年第2期80-85,共6页
针对公路网节点层次划分问题,基于运输需求理论选取有效人口数量、有效人均收入、有效运输需求量、公路通行能力作为公路网节点层次划分的影响因素。应用灰色理论,通过计算聚类系数,建立了一种新的公路网节点层次划分方法,并基于山东省1... 针对公路网节点层次划分问题,基于运输需求理论选取有效人口数量、有效人均收入、有效运输需求量、公路通行能力作为公路网节点层次划分的影响因素。应用灰色理论,通过计算聚类系数,建立了一种新的公路网节点层次划分方法,并基于山东省17个公路网节点进行实证分析。分析结果表明:应用提出的方法,根据节点重要程度可以将山东省17个公路网节点划分为3个灰类层次,第1灰类层次为公路网关键节点,包含济南、青岛、烟台、潍坊、济宁、临沂、德州、菏泽;第2灰类层次为公路网重要节点,包含淄博、泰安、聊城、滨州;第3灰类层次为公路网一般节点,包括枣庄、东营、威海、日照、莱芜。与既有划分结果相比,提出方法的划分结果更优,与山东省实际情况相符。 展开更多
关键词 公路网 运输需求 节点层次 有效人口数量 有效人均收入 公路通行能力 灰色理论 聚类分析
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Genotype-environment interaction in Cordia trichotoma(Vell.)Arráb.Ex Steud.progenies in two different soil conditions
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作者 Wanderley dos Santos Bruno Marchetti de Souza +5 位作者 Daniele Fernanda Zulian Gilberto Terra Ribeiro Alves João Bosco Vasconcellos Gomes Mário Luiz Teixeira de Moraes Valderês Aparecida de Sousa Ananda Virginia de Aguiar 《Journal of Forestry Research》 SCIE CAS CSCD 2022年第1期309-319,共11页
Investment in silvicultural techniques is noticeably lacking,especially in breeding programs for non-conventional wood species.Studying genotype×environment interaction(G×E)is essential to the development of... Investment in silvicultural techniques is noticeably lacking,especially in breeding programs for non-conventional wood species.Studying genotype×environment interaction(G×E)is essential to the development of breeding programs.Thus,this study aimed to estimate genetic diversity of and the effects of G×E interaction on two progeny tests of Cordia trichotoma,including the estimation of genetic gain and genetic diversity after selection.For the experiment,30 progenies of C.trichotoma were tested at two sites with differing soil textures.Diameter at breast height(1.30 m above soil surface,dbh-cm),total height,diameter at 30 cm from the soil,first branch height,and survival were all monitored for four years.Statistical deviance,best linear unbiased estimator,and harmonic mean of relative performance of genetic values(MHPRVG)were all calculated to predict breeding values,estimate genetic parameters,and analyze deviance.All quantified traits varied significantly among progenies by soil type,with greatest variation recorded for genetic variability.Heritability of the progenies led to predictions of genetic gain,ranging from 7.73 to 15.45%,for dbh at four years of age.The calculated decrease in genetic diversity after selection showed that this parameter should be monitored in subsequent breeding cycles.G×E was low for all tests.The best-performing progenies proved most stable and best adapted to the different environmental conditions tested. 展开更多
关键词 effective population number Native species PRODUCTIVITY Stability and adaptability Tree improvement
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