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CFG桩复合地基空孔深度控制技术 被引量:2
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作者 刘念 李波 崔挺 《施工技术》 CAS 2018年第A04期137-139,共3页
针对基础埋深较深的建筑,当采用CFG桩复合地基时,CFG桩施工和基坑开槽施工先后顺序对整个工程建设的进度、安全、质量以及经济性都有着重要的实际意义。唐山某工程考虑项目整体部署,同时为了避免雨季基坑开槽后泡槽对CFG桩施工进度和安... 针对基础埋深较深的建筑,当采用CFG桩复合地基时,CFG桩施工和基坑开槽施工先后顺序对整个工程建设的进度、安全、质量以及经济性都有着重要的实际意义。唐山某工程考虑项目整体部署,同时为了避免雨季基坑开槽后泡槽对CFG桩施工进度和安全性的影响,采用在现有地面首先施工CFG桩的方案。通过准确计算混凝土用量,选派有经验的人员控制停灰面,空孔最深达7.4m,将CFG桩保护桩长控制在0.7~1.5m,节省混凝土用量。同时通过精确放线,仔细调整钻杆垂直度,控制拔管速度,保证CFG桩成桩质量。 展开更多
关键词 CFG桩 空孔控制 施工技术
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Spatial control of palladium nanoparticles in flexible click-based porous organic polymers for hydrogenation of olefins and nitrobenzene 被引量:4
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作者 Liuyi Li 《Nano Research》 SCIE EI CAS CSCD 2015年第3期709-721,共13页
Two flexible click-based porous organic polymers (CPP-F1 and CPP-F2) have been readily synthesized. SEM images show CPP-F1 is a 3D network, while CPP-F2 exhibits a granular morphology. Pd(OAc)2 can be easily incor... Two flexible click-based porous organic polymers (CPP-F1 and CPP-F2) have been readily synthesized. SEM images show CPP-F1 is a 3D network, while CPP-F2 exhibits a granular morphology. Pd(OAc)2 can be easily incorporated into CPP-F1 and CPP-F2 to form Pd@CPP-F1 and Pd@CPP-F2, respectively. The interactions between the polymers and palladium are confirmed by solid-state 13C NMR, IR and XPS. Palladium nanoparticles (NPs) are formed after hydrogenation of olefins and nitrobenzene. Palladium NPs in CPP-F1 are well dispersed on the external surface of the polymer, while palladium NPs in CPP-F2 are located in the interior pores and on the external surface. In comparison with NPs in CPP-F1, the dual distribution of palladium NPs in CPP-F2 results in higher selectivity in the hydrogenation of 1,3-cyclohexadiene to cyclohexane. The catalytic systems can be recycled several times without obvious loss of catalytic activity or agglomeration of palladium NPs. Hot filtration, mercury drop tests and ICP analyses suggest that the catalytic systems proceed via a heterogeneous pathway. 展开更多
关键词 porous organic polymers click reaction heterogeneous catalysis PALLADIUM nanoparticles
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