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西双版纳勐养自然保护区砂仁类型的初步研究 被引量:2
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作者 王宝荣 党承林 《应用生态学报》 CAS CSCD 1997年第S1期60-64,共5页
通过西双版纳自然保护区勐养保护区栽培砂仁和野生缩砂密的实地调查 ,比较了二者的形态特征 ,以及考证了植物分类学上缩砂密是砂仁变种的确立过程后认为 :缩砂密是我国云南南部地区、广西、广东及毗邻国家山地广泛分布的野生类型 ,其个... 通过西双版纳自然保护区勐养保护区栽培砂仁和野生缩砂密的实地调查 ,比较了二者的形态特征 ,以及考证了植物分类学上缩砂密是砂仁变种的确立过程后认为 :缩砂密是我国云南南部地区、广西、广东及毗邻国家山地广泛分布的野生类型 ,其个体之间的差异明显 ,表现出多态性 .砂仁集中栽培于广东西南部 ,尽管个体之间也有差异 ,但其变异范围包含在缩砂密的变异范围内 ,是从缩砂密中选育出来的栽培类型 .二者之间的差异属于种群内的多型性 .缩砂密种群内丰富多样性为各地选育株系奠定了基础 . 展开更多
关键词 砂仁 栽培类型 缩砂密 野生类型 多型性 选种
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Compressibility dependence on grain size distribution and relative density in sands 被引量:3
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作者 SUN YiFei XIAO Yang HANIF Khairul Fikry 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第3期443-448,共6页
A framework of continuum breakage mechanics was used to investigate the dependence of compressibility on grain size distribution(GSD)as well as relative density of sand.Compressibility dependence on GSD was considered... A framework of continuum breakage mechanics was used to investigate the dependence of compressibility on grain size distribution(GSD)as well as relative density of sand.Compressibility dependence on GSD was considered by employing a GSD index and relative density dependence was reflected by varying the plastic-breakage coupling angle.Simulations of the experimental results including isotropic compression and one-dimensional compression of sands with different relative densities and GSDs revealed that sand compressibility increased with the increasing GSD index and plastic-breakage coupling angle.The coupling angle decreased with increasing relative density,indicating that grains would break more in sand with comparatively high relative density. 展开更多
关键词 grain size distribution DENSITY compression grain breakage thermo-mechanics
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