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轨道板纵向温度变形对植筋效果影响 被引量:1
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作者 路宏遥 许玉德 何越磊 《同济大学学报(自然科学版)》 EI CAS CSCD 北大核心 2023年第12期1931-1938,共8页
温度荷载作用下的轨道板纵向伸缩变形带动锚固钢筋发生偏位,结构受力状态与设计初衷产生差异。为明确轨道板温度变形对植筋实际效果的影响,首先开展纵连板式无砟轨道温度变形监测,量化表征锚固钢筋的实际偏位量;其次建立无砟轨道植筋锚... 温度荷载作用下的轨道板纵向伸缩变形带动锚固钢筋发生偏位,结构受力状态与设计初衷产生差异。为明确轨道板温度变形对植筋实际效果的影响,首先开展纵连板式无砟轨道温度变形监测,量化表征锚固钢筋的实际偏位量;其次建立无砟轨道植筋锚固精细化有限元模型,分析不同偏位条件下植筋胶层的损伤规律;最后明确了锚固钢筋偏位与脱胶耦合作用下无砟轨道的实际植筋效果。结果表明:轨道板纵向温度变形量可达0.946mm。锚固钢筋的偏位加剧了植筋胶层损伤,且呈现垂向自上而下的演变规律,是造成锚固体系脱胶失效的主要原因。植筋胶层与轨道板的脱黏削弱了锚固体系抵抗高温上拱变形的能力,当脱胶深度超过200mm后,轨道板上拱量增大了137.18%。在无砟轨道实际植筋的效果评价中需考虑轨道板的纵向温度变形,动态调整实际养护维修方案。 展开更多
关键词 无砟轨道 温度荷载 纵向变形 锚固钢筋偏 体系脱胶 植筋效果
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Pinpointing single metal atom anchoring sites in carbon for oxygen reduction: Doping sites or defects?
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作者 Cai Zhang Wei Zhang Weitao Zheng 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第1期4-7,共4页
Enabling the conversion of chemical energy of fuels directly into electricity without combustion,fuel cells are arousing great interest in both academia and industry.A typical case is the proton exchange membrane fuel... Enabling the conversion of chemical energy of fuels directly into electricity without combustion,fuel cells are arousing great interest in both academia and industry.A typical case is the proton exchange membrane fuel cell(PEMFC),already commercialized by automobile giants.For mass popularization,however,three major criteria must be balanced:performance,durability and cost.The electrocatalysts used in both the anode and cathode are the kernel of PEMFCs,being essential for efficient operation.First in the firing‐line is the oxygen reduction reaction(ORR)at the cathode,which is normally very sluggish:over six orders of magnitude slower than the anode hydrogen oxidation reaction(HOR)[1].Thus,considerable efforts have been made to improve the cathode ORR.Identifying the main active sites is key to the design of optimum materials for enhanced ORR.Considering the complex balance of preparation,performance and cost,the active sites of metal‐nitrogen‐carbon(M‐N‐C)catalysts are particularly promising.Coupled with the single metal atom(SMA)catalysts[2–5],two excellent M‐N‐C catalysts were recently reported[6,7].New insights were thereby gained into the delicate architecture of carbon‐based SMA catalysts for ORR. 展开更多
关键词 ORR HOR PEMFC
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