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指路标志与路面文字协同设置安全距离研究 被引量:5
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作者 裴玉龙 曹永臣 《武汉理工大学学报(交通科学与工程版)》 2020年第4期622-627,共6页
为解决交通指路标志信息量过多或遮挡等原因导致的驾驶人正常视认受阻的问题,考虑车辆速度、驾驶人视认特性,以及标志与标线设置位置等多方面影响因素,提出了协同距离的概念,选取城市主干路作为研究对象,进行了模拟驾驶实验.比较了路面... 为解决交通指路标志信息量过多或遮挡等原因导致的驾驶人正常视认受阻的问题,考虑车辆速度、驾驶人视认特性,以及标志与标线设置位置等多方面影响因素,提出了协同距离的概念,选取城市主干路作为研究对象,进行了模拟驾驶实验.比较了路面文字的施画对不同信息量指路标志视认效果的改善作用,分析了指路标志上各版面位置对改善作用的影响,构建了在不同设计速度、不同信息量共6种情况下,路面文字和指路标志协同设置的安全距离模型,并得到二者的最佳设置间距,作为城市主干路交通标志与标线协同设置的参考数值. 展开更多
关键词 主干路 指路标志 标线 协同设置
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DFT Study of Metal Atoms Adsorbed at Low-coordinated Sites of MgO (001) Surface
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作者 徐艺军 章永凡 +1 位作者 陈文凯 李俊篯 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2003年第6期700-704,共5页
The adsorption of metal atoms, Ni, Pd, Pt, Cu, Ag and Au, at low-coordinated edge and corner oxygen sites of MgO (001) surface has been studied theoretically by using density functional method with cluster models embe... The adsorption of metal atoms, Ni, Pd, Pt, Cu, Ag and Au, at low-coordinated edge and corner oxygen sites of MgO (001) surface has been studied theoretically by using density functional method with cluster models embedded in a large array of point charges. For comparison, the interaction of metal atoms with perfect regular oxygen site of MgO (001) surface was also calculated. As regards these metal atoms adsorbed at perfect oxygen sites of MgO (001) surface, Cu, Ag and Au are very weakly bonded to the surface of MgO; Ni, Pd and Pt, on the other hand, exhibit strong interactions with perfect oxygen sites of MgO (001) surface; the large adsorption energy shows that there exist strong bonds formed between these metal atoms with surface oxygen sites. For the metal atoms adsorbed at edge and corner sites, the adsorption energy is much increased, consistent with our previous study of CO and Cl2 adsorption on MgO (001) surface. This illustrates that the low-coordinated sites, especially corner site, are more advantageous positions for those metal atoms adsorbed on MgO (001) surface. The Mulliken population analysis indicates that the electron transferred from MgO to the metal atoms were increased with the decrease of the coordination numbers, which may be one of the reasons for changing catalytic efficiency and selectivity of the metal particles supported by MgO. 展开更多
关键词 DFT metal atoms low-coordinated sites MgO (001) surface
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