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Mechanical Properties and Fracture Mechanism of a Glass Fiber Reinforced Polypropylene Composites 被引量:2
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作者 LOU Shumei yin wenying +2 位作者 MA Xiaodong YUAN Jianjun WANG Qingbiao 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2020年第3期629-634,共6页
To study the effect of some parameters, such as, length and fraction of glass fiber (GF), and the fraction of maleic anhydride grafted polypropylene (PP-g-MAH), on the mechanical properties of glass fiber reinforced p... To study the effect of some parameters, such as, length and fraction of glass fiber (GF), and the fraction of maleic anhydride grafted polypropylene (PP-g-MAH), on the mechanical properties of glass fiber reinforced polypropylene (GF/PP) composites, tensile tests, bending tests and impact tests were conducted. Scanning electron microscope (SEM) was used to characterize the fracture mechanisms of the composites. The results show that, compared with 3 mm GF, 9 mm GF can significantly improve the strength of the composite better. Addition of PP-g-MAH, a kind of grafting agent, into the PP-30% LGF composite can result in a better mechanical properties because of the strengthening of the bonding interface between the matrix and the fiber. When the mass fraction of GF is 30% and the PP-g-MAH fraction is 6%, the mechanical properties of the composite are the best. 展开更多
关键词 GF/PP mechanical properties maleic anhydride grafted polypropylene(PP-g-MAH) fracture mechanisms
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直流式双风机隔离小室运行效果模拟分析
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作者 尚世杰 吕洁 +2 位作者 尹文颖 周雨宁 路睿峰 《洁净与空调技术》 2021年第1期12-15,共4页
直流式双风机隔离小室是一种为常态化防疫设计的封闭小室,在医院疫情防控期间可将病患与正常人分隔开来,能根据污染源的不同位置,通过调节风机转速使小室维持正压或负压状态以达到隔离或防护的作用。为了确定设计参数是否满足室内空气... 直流式双风机隔离小室是一种为常态化防疫设计的封闭小室,在医院疫情防控期间可将病患与正常人分隔开来,能根据污染源的不同位置,通过调节风机转速使小室维持正压或负压状态以达到隔离或防护的作用。为了确定设计参数是否满足室内空气安全性和人体热舒适性的要求,采用计算流体力学CFD方法对小室内空气的温度场、速度场以及负压条件下病原体颗粒的运动轨迹进行了模拟。模拟结果表明,在送风温度25℃、平均风速0.25m/s的设计参数下,小室内竖向速度场和温度场相对均匀,人体对吹风感的不满意率在10%左右,对垂直温差的不满意率在1%以下;在送风量130 m^(3)/h、室内外压差为5Pa、缝隙面积0.018 m^(2)的负压条件下,小室内病原体颗粒不能逃逸出室外。 展开更多
关键词 双风机 隔离 疫情防控 吹风感 垂直温差
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Phylogeny of higher taxa of hexapoda according to 12sRNA sequences
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作者 ZHANG Yazhou ZHANG Yaping +2 位作者 LUAN Yunxia CHEN Yongjiu yin wenying 《Chinese Science Bulletin》 SCIE EI CAS 2001年第10期840-842,共3页
The phylogenetic relationship of Hexapoda has been debated for a long time, which will be resolved mainly depending on the settlement of monophyly, affinities and interrelationships among Protura, Collembola and Diplu... The phylogenetic relationship of Hexapoda has been debated for a long time, which will be resolved mainly depending on the settlement of monophyly, affinities and interrelationships among Protura, Collembola and Diplura. Mitochondrial 12sRNA gene about 355 bp fragments from one proturan species, two collembolan species, two dipluran species and one oribatid species were sequenced. The Ki-mura 2-parameter distances were calculated and a series of molecular phylogenetic trees were reconstructed by using the N-J method, from which the following points were drawn: (i) Protura and Collembola compose a monophyletic group representing absent-cerci; (ii) Diplura is not a monophyletic group, in which Campodeoid with filiform cerci belongs to a clade and Japygoid with pincer cerci and Ectognatha compose another clade, that is, Insecta s. str. stemmed from Japygoid. So it would be suggested that the phylogenetic relationship of Hexapoda is [Parainsecta (Collembola + Protura) +Campodeoid +Insecta (Japygoid + 展开更多
关键词 HEXAPODA 12sRNA PHYTOGENY higher TAXA monophyly.
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