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聚纤纺牵伸形式的技术性能分析 被引量:3
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作者 程登木 《棉纺织技术》 CAS CSCD 北大核心 2012年第4期15-18,共4页
探讨一种新型集聚纺纱技术——聚纤纺牵伸形式的技术特点与纺纱性能。分析了聚纤纺牵伸形式的结构特点及纺纱性能,并在理论与实际纺纱两方面与传统双胶圈牵伸形式进行了对比分析。聚纤纺牵伸形式突破了上下胶圈的束缚,在结构及纺纱原理... 探讨一种新型集聚纺纱技术——聚纤纺牵伸形式的技术特点与纺纱性能。分析了聚纤纺牵伸形式的结构特点及纺纱性能,并在理论与实际纺纱两方面与传统双胶圈牵伸形式进行了对比分析。聚纤纺牵伸形式突破了上下胶圈的束缚,在结构及纺纱原理上实现了先集聚后牵伸、运用负压、网格圈和控制棒实现对纤维更有效、合理的控制,从而改善成纱条干并形成合理的成纱毛羽结构。试验结果表明:该牵伸形式能够明显改善成纱质量水平,特别是成纱条干能够比较容易地达到乌斯特2007公报5%水平。认为:该牵伸形式能够改善生产环境,简化生产管理,降低机物料及能源消耗。 展开更多
关键词 双胶圈牵伸 聚纤纺 牵伸控制 毛羽形态 条干 能耗
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Hawk mimicry and the evolution of polymorphic cuckoos 被引量:3
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作者 Rose THOROGOOD Nicholas B.DAVIES 《Chinese Birds》 CSCD 2013年第1期39-50,共12页
The resemblance of some parasitic cuckoos to Accipiter hawks has been known since ancient times. Recent experiments show that the hawk-like features of Common Cuckoos (Cuculus canorus) facilitate access to Reed Warble... The resemblance of some parasitic cuckoos to Accipiter hawks has been known since ancient times. Recent experiments show that the hawk-like features of Common Cuckoos (Cuculus canorus) facilitate access to Reed Warbler (Acrocephalus scirpaceus) host nests. However, social information alerts hosts to see through the cuckoo’s mimetic disguise. In turn, this has promoted the evolution of a cuckoo polymorphism to thwart host recognition. Here we show by comparative analyses that parasitic cuckoos with hawk-like features (yellow eyes, barred underparts, yellow legs) are more likely to be polymorphic (29% of species) than those without (8% of species). Phylogenetic analyses confirm correlated evolution of hawk-like features and cuckoo polymorphism. We suggest that mimicry dynamics are particularly likely to promote the evolution of various guises in parasitic cuckoos to beat host defences. 展开更多
关键词 Batesian mimicry brood parasitism phylogenetic analysis plumage morph POLYMORPHISM
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