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近地面强中子源辐射环境场分布的蒙特卡罗计算
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作者 牛进林 左应红 +2 位作者 商鹏 牛胜利 朱金辉 《现代应用物理》 2023年第4期47-52,共6页
针对强中子源在地面附近大气中形成的辐射场,研究地面介质对中子辐射场的影响,采用蒙特卡罗方法,模拟计算了不同高度单能中子源在地面高度1 m处形成的中子组织剂量分布。研究结果表明:与自由大气模型相比,由于地面介质的存在,在近源区... 针对强中子源在地面附近大气中形成的辐射场,研究地面介质对中子辐射场的影响,采用蒙特卡罗方法,模拟计算了不同高度单能中子源在地面高度1 m处形成的中子组织剂量分布。研究结果表明:与自由大气模型相比,由于地面介质的存在,在近源区中子组织剂量因地面反射而增强,在远源区,地面的屏蔽对中子组织剂量起削弱作用;针对某个探测点,存在一个最大剂量源高,并给出了最大剂量源高随水平投影距的变化关系拟合关系式,分布中子源算例表明,该拟合关系式具有一定的通用性。 展开更多
关键词 强中子源 环境场 源高度 水平投影距 地面介质
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不同花纹鞋底的止滑性能的研究 被引量:5
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作者 罗向东 刘呈宁 张秋萍 《中国皮革》 CAS 北大核心 2016年第5期49-51,56,共4页
为了探究不同花纹鞋底的止滑结构,使用肘节止滑测试仪,选择均匀圆点状、密集无规则状、波浪状3种花纹鞋底,在常见纯净水、普通食用油、一定浓度洗涤剂水溶液3种介质中,以及分别在大理石地面、普通瓷砖地面、打蜡木面、玻璃面4种常见光... 为了探究不同花纹鞋底的止滑结构,使用肘节止滑测试仪,选择均匀圆点状、密集无规则状、波浪状3种花纹鞋底,在常见纯净水、普通食用油、一定浓度洗涤剂水溶液3种介质中,以及分别在大理石地面、普通瓷砖地面、打蜡木面、玻璃面4种常见光滑表面地面上,进行止滑试验,得到摩擦系数COF值,并比较其止滑性能的强弱。结果表明:不同光滑表面地面上,鞋底的止滑性受鞋底花纹形状和介质的影响很大。 展开更多
关键词 鞋底花纹 地面介质 止滑 摩擦系数 光滑表面
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Prediction of ground surface displacement caused by grouting 被引量:3
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作者 郭风琪 刘晓潭 +1 位作者 童无期 单智 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3564-3570,共7页
Ground surface displacement caused by grouting was calculated with stochastic medium theory. Ground surface displacement was assumed to be caused by the cavity expansion of grouting, slurry seepage, and slurry contrac... Ground surface displacement caused by grouting was calculated with stochastic medium theory. Ground surface displacement was assumed to be caused by the cavity expansion of grouting, slurry seepage, and slurry contraction. A prediction method of ground surface displacement was developed. The reliability of the presented method was validated through a comparison between theoretical results and results from engineering practice. Results show that the present method is effective. The effect of parameters on uplift displacement was illustrated under different grouting conditions. Through analysis, it can be known that the ground surface uplift is mainly caused by osmosis of slurry and the primary influence angle of stratum β determines the influence range of surface uplift. Besides, the results show that ground surface uplift displacement decreases notably with increasing depth of the grouting cavity but it increases with increasing diffusion radius of grout and increasing grouting pressure. 展开更多
关键词 GROUTING ground surface displacement stochastic medium theory SEEPAGE slurry solidification shrinkage
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Energy flux characteristics of seismic waves at the interface between soil layers with different saturations 被引量:12
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作者 CHEN WeiYun CHEN GuoXing +1 位作者 XIA TangDai CHEN Wei 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第10期2062-2069,共8页
Based on the multiphase poroelasticity theory describing the propagation of waves in the unsaturated fluid-saturated porous medium,the reflection and transmission coefficients of the seismic waves at the interface bet... Based on the multiphase poroelasticity theory describing the propagation of waves in the unsaturated fluid-saturated porous medium,the reflection and transmission coefficients of the seismic waves at the interface between soil layers with different saturations are obtained.Our unsaturated model consists of a deformable skeleton in which two compressible and viscous fluids(i.e.,water and gas)flow in the interstices.Three compressional waves(i.e.,P1,P2,and P3 waves)and one shear(i.e.,S wave)wave exist in the unsaturated soils.The expressions for the energy ratios of the various reflected and transmitted waves at the interface during the transmission and reflection processes are presented in explicit forms accordingly.At last,numerical computations are performed and the results obtained are respectively depicted graphically.The variation of the energy ratios with the incident angle,wave frequency and saturation degrees of the upper and lower soil layers is illustrated in detail.The calculation results show that the allocation of incident seismic waves at the interface is influenced not only by the angle and frequency of the incident seismic waves,but also by the saturations of the upper and lower soil layers.It is also verified that,at the interface,the sum of energy ratios of the reflected and transmitted waves is approximately equal to unity as was expected.This study is of importance to several fields such as geotechnical engineering,seismology,and geophysics. 展开更多
关键词 energy flux characteristics seismic waves unsaturated soils wave reflection wave transmission
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