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光束质量评价的新进展
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作者 徐大刚 马冲 《大连理工大学学报》 EI CAS CSCD 北大核心 1997年第S2期49-49,共1页
光束质量评价的新进展徐大刚马冲(中国计量科学研究院北京100013)目前光束质量评价的主要依据是1995年的ISO/DIS11146国际标准文件。该文件规定了束宽、发散角、光束传输因子K2和倍衍射极限因子M2的定义及... 光束质量评价的新进展徐大刚马冲(中国计量科学研究院北京100013)目前光束质量评价的主要依据是1995年的ISO/DIS11146国际标准文件。该文件规定了束宽、发散角、光束传输因子K2和倍衍射极限因子M2的定义及其测定方法。它主要采用二阶矩束宽定... 展开更多
关键词 光束质量 激光束 光束特性 光束传输因子 二氧化碳激光 高斯光束 双曲线方式 参数测试方法 中国计量科学研究院 光束均匀性
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Evaluation of surface textures and skid resistance of pervious concrete pavement 被引量:7
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作者 陈瑜 王科进 周文芳 《Journal of Central South University》 SCIE EI CAS 2013年第2期520-527,共8页
Surface textures had long been recognized as primary factors to provide the skid resistance on pavements; however, no measurement of skid resistance on pervious concrete pavement with various surface texture parameter... Surface textures had long been recognized as primary factors to provide the skid resistance on pavements; however, no measurement of skid resistance on pervious concrete pavement with various surface texture parameters had been made. Fractal geometry was introduced in the present work to accurately simulate transect contour curves of pervious concrete specimens through fractal interpolation. It is proved that its fractal dimension (D) can be adopted to measure the skid resistance on pervious concrete pavement, overcoming the shortcomings of both macrotexture depth (DT ) and British portable pendulum number (NBP). Combined with Fujikawa-Koike tire/road contact model, the optimization method of all surface textures was recommended for designing and constructing excellently skid-resistant and noise-absorptive pervious concrete pavement. In addition, evaluating of the abrasion process and attenuation of the surface textures on concrete pavement slabs was also the focus of this work based on accelerated abrasion test. Results show that the surface textures on pervious concrete pavement slabs is extremely durable, compared to those on conventional grooved or exposed aggregate concrete pavement slabs. 展开更多
关键词 pervious concrete surface texture skid resistance fractal dimension ABRASION
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