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本文对求解土壤或岩石中氡浓度及其表面析出率的边界条件进行了探讨。以空气中无穷远处氡浓度为零(空气中无氡源)的自然边界条件代替空气与土壤或岩石交界面氡浓度为零的边界条件,给出了土壤和岩石中氡浓度及其表面析出率的具体表达式。与前人研究结果比较,该式中增加了一项,表面氡析出率缩小了一个倍数。通过对土壤、岩石的具体计算.表明两种边界条件的计算结果有相当的偏差。同时,文中还讨论了在两类边界条件下对流对土壤或岩石中氡浓度及其表面析出率计算的影响。 相似文献
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采用IED-3000R轻便型测氡仪,对四川阿坝地区土壤、空气中的氡气浓度开展初步调查。结果表明:(1)测区空气中氡气浓度较高,均在平均值185 Bq/m3附近;(2)所测得土壤的氡气浓度范围为2 736~93 486 Bq/m3,平均值为26 021 Bq/m3,远远高于全国城市土壤中氡气浓度7 300 Bq/m3的平均值,同时在156个土壤氡气浓度被测点中共有91个测点氡气浓度值超过20 000 Bq/m3,而按照国家标准,对于民用建筑工程土壤中氡气浓度超过20 000 Bq/m3要进行不同程度的防氡工程;(3)地质环境、土壤松散度、岩土性质、土壤含水率为影响阿坝地区土壤氡气浓度的主要因素。 相似文献
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土壤氡浓度日变化影响因素研究 总被引:1,自引:0,他引:1
地表壤氡可以反映地下深部的水文、地质、矿产、热源等信息,但土壤氡浓度有年变和日变的特点。为了研究土壤氡浓度日变化规律及其影响因素,采用α能谱测氡仪对土壤氡进行连续测量。结果表明:土壤氡浓度呈单峰型日变化特征,最大值出现在19:00~22:00,最小值出现在11:00~14:00,土壤温度是影响土壤氡浓度的关键因子,土壤氡浓度与土壤温度呈正相关。降雨对土壤氡浓度有显著的影响,降雨后土壤氡浓度出现双峰型日变化特征,其变化与土壤湿度和空气温度等气象因素有关。 相似文献
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在广东珠海地区采用便携式半导体测氡仪进行了大比例尺土壤氡浓度调查,测点数469个,面积大于100km2。珠海地区地下0.6 m处的平均土壤氡浓度为55.94±58.54 kBq/m3,其中在珠海斗门的第四纪沉积物地区、沉积物和风化花岗岩混合地区,以及风化花岗岩地区的土壤氡浓度分别是7.14±8.75,37.64±25.92和151.25±196.23 kBq/m3。高氡潜势区主要分布在黑云母花岗岩、风化花岗岩地区和新的工业开发区,且表现出与当地岩性密切相关。城市化和工业化改变了原有的天然辐射背景。珠海市区的平均土壤氡浓度分别为广州、泉州和晋江市平均值的8.3倍和15倍。研究结果表明:珠海是一个氡潜势较高的区域,需要进一步开展辐射防护目的的氡测量。 相似文献
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In the Ljubljana region, 53 schools were selected for measurements of radon concentrations in soil gas close to a school building, and indoor radon concentrations in one of the ground-floor classrooms of each building. The aim was to establish a relationship between radon concentrations in indoor air and in soil gas from the ground on which the building is situated. Soil gas radon concentrations between 2 and 14 kBqm-3 were found. Indoor radon concentrations ranged from 20 to 1,440 Bqm-3, with seven values exceeding 200 Bqm-3. It is concluded that good quality of the construction elements ensure low indoor radon concentration, regardless of high soil gas radon level. 相似文献
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青岛市环境氡浓度分布规律与预测方法研究 总被引:2,自引:0,他引:2
通过研究青岛市环境氡的分布规律,认为青岛虽然处在崂山花岗岩上,但由于土壤层不厚,土壤储气条件不好以及氡浓度很低的海风作用,青岛土壤氡浓度和空气氡浓度都不高。提出了一种新的土壤氡浓度预测方法,即利用现有地质资料中铀的含量评价环境氡浓度水平。 相似文献
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High indoor radon concentrations in a uranium-radium low-level area in the Eifel region, Germany, near the village of Döttingen are caused by ascending radon migration following the convection of groundwater and soil gas along pathways (fractures and faults) in the bedrock sediments of Lower Devonian age. Positive radon anomalies in the soil gas are found to coincide with the locations of houses showing the highest concentrations. These houses are older buildings without concrete foundation slabs. Normally radon concentrations in soil gas are highly correlated with the values of emanated radon calculated on the basis of radium content in the surrounding soils and rocks (diffusive radon potential). However, close to zones of tectonic fractures and faults around the maar-type volcano of Döttingen abnormally high radon concentrations, which were transported by circulating groundwater and postvolcanic exhalation of CO2 (convective radon potential) were detected. 相似文献