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聚丙烯纤维-钢筋/混凝土管节受力性能试验 被引量:11
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作者 刘新荣 陈鹏 +2 位作者 邓志云 梁宁慧 谢应坤 《复合材料学报》 EI CAS CSCD 北大核心 2021年第12期4349-4361,共13页
顶管施工中钢筋/混凝土管节存在开裂现象,严重影响工程质量与后续营运。鉴于聚丙烯纤维具有改善混凝土抗拉、抗裂性能的作用,本文采用2种聚丙烯细纤维和1种聚丙烯粗纤维,设计了无纤维、单掺粗纤维及混掺三种尺度纤维的3组钢筋/混凝土管... 顶管施工中钢筋/混凝土管节存在开裂现象,严重影响工程质量与后续营运。鉴于聚丙烯纤维具有改善混凝土抗拉、抗裂性能的作用,本文采用2种聚丙烯细纤维和1种聚丙烯粗纤维,设计了无纤维、单掺粗纤维及混掺三种尺度纤维的3组钢筋/混凝土管试件,进行了三点试验,对比分析管节的开裂破坏形态、荷载挠度曲线和开裂延性指标。并建立纤维混凝土管节三点试验的有限元模型,进一步探究聚丙烯纤维掺量对钢筋/混凝土管节受力性能的影响规律。结果表明,聚丙烯粗纤维可提高混凝土管的抗裂与承载能力,聚丙烯粗、细纤维的协同作用使管达到更高的使用和极限强度。相比无纤维管,混掺多尺度纤维提升管的使用强度和极限强度分别为28.7%和36.4%。此外,数值模拟合理地预测了纤维/混凝土管节的荷载挠度响应,并针对混凝土管节的极限强度值,得到单掺和混掺聚丙烯纤维时粗纤维的最佳掺量。 展开更多
关键词 聚丙烯纤维 钢筋/混凝土管节 三点试验 受力性能 数值模拟
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The Use of Floss in Medical Faculties of Inner Mongolia Medical University in 2017
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作者 Cong Chen Lijuan Shang +11 位作者 Li Jiang Huichao Zhang Xin Wei xinrong liu Zeyu Lu Zhenduo Zhang Liying Gao Yuan Chen Yaxuan Hou Qingxia Wang Ming Jia Juan Sun 《Open Journal of Epidemiology》 2020年第3期195-202,共8页
<strong>Purpose:</strong> The aim of the present study was to determine the degree of using floss and the demographic characteristics of medical faculties of Inner Mongolia Medical University. <strong&g... <strong>Purpose:</strong> The aim of the present study was to determine the degree of using floss and the demographic characteristics of medical faculties of Inner Mongolia Medical University. <strong>Materials and Methods:</strong> Participants completed the questionnaire in the classroom. These participants came from the medical faculties of Chinese Medicine and Western Medicine. These participants were interviewed to determine the demographic characteristics. Non-flossors responded according to their reasons for not flossing. <strong>Results:</strong> A total of 3481 effective data were available for analysis. The floss prevalence was 17.21%, which was lower by 5.72% for students living in rural areas, when compared to students living in urban areas. The largest proportion of non-flossing participants in rural areas answered, “I do not know what a floss is”, while participants in urban answered, “I do not want to use it”. The largest proportion of answered flossing frequency was less than once a month. <strong>Conclusion:</strong> The present study indicates that the prevalence of using floss in medical faculties in Inner Mongolia Medical University was higher, when compared to that in Sichuan province, China, but lower than that in other countries. Although the students use floss, more than one-third of students use floss less than once a month, which is close to “never”. The prevalence in rural areas is lower than those in urban areas. Male not only comprises the total number of prevalence, but also has a frequency greater than that in females. The emphasis on using floss should be improved in medical students. 展开更多
关键词 Floss Oral Health Behavior REGION Medical Students
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热压对短碳纤维增强2024复合材料组织和性能影响 被引量:1
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作者 王飞舟 杨瑞宾 +3 位作者 张云杰 谭欣荣 刘小方 刘忠侠 《特种铸造及有色合金》 CAS CSCD 北大核心 2017年第9期1002-1006,共5页
采用真空热压烧结工艺制备了纤维长度为3mm、质量分数为3%的短碳纤维增强2024铝基复合材料。研究了热压工艺对复合材料密度、晶粒尺寸、界面结构和硬度的影响。结果表明,在450℃、50MPa下保温50min时,复合材料致密程度较高,纤维与α(Al... 采用真空热压烧结工艺制备了纤维长度为3mm、质量分数为3%的短碳纤维增强2024铝基复合材料。研究了热压工艺对复合材料密度、晶粒尺寸、界面结构和硬度的影响。结果表明,在450℃、50MPa下保温50min时,复合材料致密程度较高,纤维与α(Al)基体的界面结合良好,硬度达到最高。由于镀铜层提高了纤维与α(Al)基体的润湿性,镀铜短碳纤维比没有镀铜的短碳纤维对复合材料的性能提高更显著。 展开更多
关键词 短碳纤维增强铝基复合材料 真空热压烧结 界面 硬度
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