排序方式: 共有28条查询结果,搜索用时 15 毫秒
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采用毛细管动态流变仪,选用PELD、PP、PS和PA等典型物料,研究了毛细管动态挤出下各聚合物熔体的非线性流变行为。结果表明,不同物料的流变行为对振动力场的响应特性有较大差异,只有在一定的振幅和频率下振动力场才能有效降低熔体的黏度。实验首次发现,PP、PS和PA存在窄的振动参数区域,在此区域内,熔体的动态表观黏度值大于相应的稳态值,出现“加振变黏”现象。这一新的发现表明,并非“只要引入振动就一定有利于聚合物材料的成型加工”,必须考虑不同分子结构的聚合物材料对振动的不同响应规律。 相似文献
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Wang Jie Shen XuHui Yang YanYan Zeren ZhiMa Hulot Gauthier Olsen Nils Zhou Bin Magnes Werner De Santis Angelo Huang JianPing Guo Feng Liu WenLong Yu JingBo 《中国科学:技术科学(英文版)》2021,64(5):1118-1126
Science China Technological Sciences - The China Seismo-Electromagnetic Satellite (CSES), China’s first satellite to measure geophysical fields with scientific goals in both space and solid... 相似文献
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三种挤压粉磨设备粉磨稳定性比较 总被引:2,自引:0,他引:2
从分析现行三种料层挤压粉磨的工作机理入手,提出影响粉磨稳定性的结构因素是粉磨通道截面收缩率不同,进一步阐述了通道截面宽度特征值数学模型,导出三种料层挤压粉磨截面收缩率表达式,提出在临界钳入压力角处,三种挤压通道的截面收缩率相等的论断。并以此为据,计算立磨、筒辊磨的临界钳入压力角,与现行粉磨的理论与实践引证,得出结论。 相似文献
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以对氯苯胺和三光气为原料,合成对氯苯异氰酸酯。通过考察溶剂、反应时间、原料摩尔比、反应温度和缚酸剂等因素的影响,获得了最佳反应条件,收率可达81%。 相似文献
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Xiao-Feng Pan Zhiwei Bao WenLong Xu Huai-Ling Gao Bao Wu YinBo Zhu Guan-Hua Yu Jungen Chen Si-Chao Zhang Liangbin Li Heng-An Wu Xiaoguang Li Shu-Hong Yu 《Advanced functional materials》2023,33(9):2210901
The emerging aramid-mica nanopapers, composed of aramid nanofibers (ANFs) and mica nanosheets (Mica), exhibit superiority in the field of electrical insulation compared with commercial aramid-mica micropapers. Unfortunately, their mechanical and electrical insulating properties are still less than ideal due to insufficient control of their microstructures. Herein, it is presented that by integrating ANFs and Mica into nacre-like aramid-mica nanopapers with improved structural orderliness, densification, and interlayer interaction, simultaneously improved mechanical and electrical insulating properties are achieved. Their maximum tensile strength and breakdown strength reach ≈292 MPa and ≈176 kV mm−1, respectively, which are superior to those of the state-of-the-art ANFs-based nanopapers. Particularly, the aramid-mica nanopapers show high resistance to high-temperature (250–300 °C) and oil-bath (100 °C) environments commonly involved in practical applications, and can be recycled many times, demonstrating their great potential as high-performance sustainable electrical insulating papers to be applied in advanced electrical equipment. 相似文献
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