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高速铁路基础结构动态性能演变及服役安全的基础科学问题 被引量:89
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作者 翟婉明 赵春发 +5 位作者 夏禾 谢友均 黎国清 蔡成标 罗强 宋小林 《中国科学:技术科学》 EI CSCD 北大核心 2014年第7期645-660,共16页
中国高速铁路已经由大规模建造进入长期安全稳定运营阶段,如何科学维护庞大规模的高速铁路运营线路,使高速铁路长期保持高安全、高稳定、高可靠的运营品质,是我国现阶段面临的重大课题.在分析总结中国高速铁路基础结构构造特点及其复杂... 中国高速铁路已经由大规模建造进入长期安全稳定运营阶段,如何科学维护庞大规模的高速铁路运营线路,使高速铁路长期保持高安全、高稳定、高可靠的运营品质,是我国现阶段面临的重大课题.在分析总结中国高速铁路基础结构构造特点及其复杂运营环境特点的基础上,提出了高速铁路基础结构动态性能演变及服役安全的三个基础科学问题:环境与动载耦合重复作用下高速铁路基础结构关键工程材料与结构动态性能演变,高速铁路基础结构累积变形与轨面几何形态的映射关系,基础结构劣化与高速列车-基础结构耦合系统动态性能的相互影响及演化机制;回顾评述了国内外在此方面的研究现状与最新进展;指出了本领域今后的发展趋势以及需要重点关注和加强的基础研究工作. 展开更多
关键词 高速铁路 轨道结构 铁路桥梁 路基 动态性能演变 列车运行安全
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Rheo-diecasting of AZ91D magnesium alloy by taper barrel rheomoulding process 被引量:5
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作者 杨柳青 康永林 +2 位作者 张帆 丁瑞华 李炯 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第6期966-972,共7页
A self-developed taper barrel rheomoulding(TBR)machine was introduced,and the rheo-diecasting process was implemented by combining TBR machine with the high pressure die casting(HPDC)machine.Microstructural characteri... A self-developed taper barrel rheomoulding(TBR)machine was introduced,and the rheo-diecasting process was implemented by combining TBR machine with the high pressure die casting(HPDC)machine.Microstructural characteristics of the rheo-diecasting components were investigated at different rotation speeds.Flow characteristics and microstructural evolution of the semi-solid slurry during the rheo-diecasting process were analyzed and the mechanical properties of the rheo-diecasting components were studied.The experimental results show that the process is able to obtain such components in which the primaryα-Mg particles are fine,nearly spherical and uniformly distributed in the matrix.When the rotation speed of internal taper barrel is 700 r/min,the primaryα-Mg particles get a mean diameter of about 45μm and a shape factor of about 0.81.The magnesium alloy melt has complex stirring-fixed flow characteristics when flowing in TBR machine.Compared with conventional die-casing process,the rheo-diecasting process can improve the mechanical properties of components;especially,the elongation is improved by 80%. 展开更多
关键词 AZ91D magnesium alloy RHEO-DIECASTING MICROSTRUCTURE flow characteristics mechanical properties
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Structure and property of metal melt Ⅳ——Evolution of titanium melt residual bond structure and its effect on dynamic viscosity 被引量:3
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作者 MI GuangBao CAO JingXia +3 位作者 HUANG Xu CAO ChunXiao LIPeiJie HE LiangJu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第8期1371-1375,共5页
Based on the concept of melt residual bonds, a calculating model quantitatively describing the evolution of the residual bond structure of titanium melt at the melting point or in a certain range above the melting poi... Based on the concept of melt residual bonds, a calculating model quantitatively describing the evolution of the residual bond structure of titanium melt at the melting point or in a certain range above the melting point was established; i.e., both the size ds and the bond number n of the residual bond structure decrease monotonously with the increase of temperature. By mathe- matical deduction, a linear relationship between the residual bond structure size ds and the dynamic viscosity 17 of Titanium melt was revealed, i.e., η= 0.876 + 0.471·ds, which is of great significance to the investigation of the relationship between the melt microstructure and the macroscopic properties of metals with high melting temperature. 展开更多
关键词 titanium melt residual bond structure dynamic viscosity calculating model
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