磷酸盐水泥对137Cs的固化性能

以含95％MgO的重烧镁砂、磷酸盐和硼砂为原料,制备了磷酸盐水泥,研究其对137Cs的固化性能。通过XRD衍射分析、SEM电镜扫描等手段对固化体物相组成及显微结构进行分析,参照国家标准“放射性废物固化体长期浸出试验”（GB7023—86）对固化体进行抗浸出性能试验。结果表明,当以磷酸氢二铵为原料时,137Cs的加入会降低磷酸盐水泥固化体的抗压强度,137Cs的含量越多,强度损失越小;当以磷酸二氢铵为原料时,随着137Cs的加入,强度先减小后增大,掺量为1．6％时强度甚至超过了空白体系;以磷酸二氢钾为原料时,137Cs的加入会使强度减小,减小程度和掺量关系的规律性不明显。以磷酸二氢铵、磷酸二氢钾为原料的固化体抗压强度明显优于以磷酸氢二铵为原料的固化体。以磷酸二氢铵为原料的固化体,137Cs的42d浸出率和累计浸出分数低至2．1×10-4（em·d11）和7．74×10^-3cm,强度值和浸出率均优于国家标准相关要求,表明了磷酸盐水泥对137Cs有良好的固化效果。     

放射性核素铯-137在土壤里不同质地中的分布规律

通过测定不同颗粒大小的土壤样品所含核素铯-137的比活度,发现土壤所含铯-137的比活度与土壤表面积存在着对数相依关系.     

基于137Cs示踪技术的土壤侵蚀研究进展

由于应用137Cs示踪技术能够提供土壤侵蚀与沉积信息,近年来137Cs示踪技术逐渐成为土壤侵蚀研究的重要方法．本文介绍了137Cs示踪法原理,回顾了其在土壤侵蚀中的研究应用,并对其优缺点进行评价．然后,总结了。137Cs示踪剂法土壤侵蚀模型,最后展望了其在土壤侵蚀研究中的前景．     

Characteristics of 137Cs deposition in steppe area

Soil wind erosion in the semiarid steppe area was studied using the 137Cs tracing technique. Comparisons of 137Cs deposition characteristics between different soil profiles indicated that slight aeolian activities occurred on sandy grasslands and semi-fixed dunes with erosion/deposition rates of less than 0.108 cm/a, whereas they were intense on semi-shifting dunes with erosion/deposition rates of higher than 1.35 cm/a.     

137 Cs在土壤中淋溶迁移的模拟试验

~(137)Cs作为示踪元素广泛应用于土壤侵蚀及泥沙沉积研究中,其在土壤中的稳定性是决定其能否用于示踪土壤沉积与侵蚀的前提条件.但也有学者对应用~(137)Cs示踪技术的重要假设提出质疑,认为被土壤颗粒吸附的~(137)Cs易解吸成Cs+离子,随水流失或被植物吸收.本文利用双层土柱模拟淋溶装置研究了~(137)Cs和土壤粒径组成在不同雨量条件下的淋失和垂直迁移特征.结果表明,在600~3 000mm降雨量内,土壤中~(137)Cs平均质量活度为10.9Bq·kg-1,略小于试验前的11.5Bq·kg~(-1),与雨量并无显著相关性,土壤中的~(137)Cs有向下垂直迁移现象,但并不显著;土壤中~(137)Cs质量活度与土壤中的黏粒含量有很好的正相关性,决定系数R2达到0.73;有待于增加模拟雨量,作进一步研究.     

Characteristics of 137Cs deposition in steppe area

Soil wind erosion in the semiarid steppe area was studied using the ¹³⁷Cs tracing technique. Comparisons of ¹³⁷Cs deposition characteristics between different soil profiles indicated that slight aeolian activities occurred on sandy grasslands and semi-fixed dunes with erosion/deposition rates of less than 0.108 cm/a, whereas they were intense on semi-shifting dunes with erosion/deposition rates of higher than 1.35 cm/a.     

土壤侵蚀137Cs法研究进展

同位素1 37Cs示踪技术具有简单、快速、准确的优点 ,它已广泛应用于土壤侵蚀的研究中 .本文先简单概述了现代土壤侵蚀速率的研究方法 ,然后着重综述了1 37Cs法在土壤侵蚀研究中的应用及其研究进展 (主要集中在1 37Cs的空间分布、土壤侵蚀速率计算模型、土壤侵蚀量估算模型等方面 ) ,最后提出未来1 37Cs法在土壤侵蚀研究中的发展趋势     

Preliminary results of the study on wind erosion in the Qinghai-Tibetan Plateau using 137Cs technique

The worldwide fallout of caesium-137 (137Cs) associated with the nuclear weapon tests during the 1950s and 1960s has provided a valuable man-made tracer for studies of soil erosion and sediment delivery. But relatively few researchers have used it to estimate wind erosion. In this note, the 137Cs technique is introduced into the studies of wind erosion and its modern processes in the Qinghai-Tibetan Plateau. Two 137Cs reference inventories of 982.11 and 2 376.04 Bq·m-2 were established preminarily, distributed in the south and middle-north parts of the studied area respectively. By analyzing the patterns of 137Cs depth profiles from sampling sites, the aeolian processes of erosion and deposition in nearly 40 years have been revealed, i.e. the shrub coppice dunes (S1) and semi-fixed dunefields (S3) experienced the alternation of erosion and deposition, while the grasslands (S4, S6 and S7) and dry farmlands (S5) suffered erosion only. By using 137Cs model, the average wind erosion rates for shrub coppice dune (S1), semi-fixed dune fields (S3), dry farmlands (S5) and grasslands (S4, S6 and S7) were estimated to be 84.14, 69.43, 30.68 and 21.84 t·ha-1·a-1 respectively, averaging 47.59 t·ha-1·a-1 for the whole plateau, which can be regarded as of the medium erosion standard. These results derived from 137Cs for the first time have significant implications for the further research of wind erosion and desertification control in the Qinghai-Tibetan Plateau.     

基于淤地坝淤积信息的小流域泥沙来源及产沙强度研究

根据黄土丘陵区王茂沟流域关地沟3号淤地坝29年泥沙沉积旋回变化,以及各旋回层泥沙中、坝控流域沟间地和沟谷地表层土壤中137Cs的测量,结合淤地坝修建、运行历史资料及次降雨资料,估算了坝控流域沟间地和沟谷地的相对产沙量和坝控流域不同时期的侵蚀产沙强度。研究表明,沟间地是该小流域泥沙主要来源,该流域泥沙的70%源自沟间地;坝控流域1959~1987年期间,年侵蚀产沙强度由强变弱,呈显著降低趋势。     

广西北部湾河口及海湾沉积物中137Cs含量分析

【目的】了解广西北部湾河口及海湾沉积物中~(137)Cs的含量,为定量研究北部湾沿岸区域土壤侵蚀和堆积状况,以及评价防城港红沙核电站运行对周围环境的影响提供科学依据。【方法】在广西北部湾河口及海湾中采集32个沉积物样品,利用高纯锗γ谱仪测定样品中~(137)Cs的含量,并与周边的背景值进行比较。【结果】在河口、海湾的表层样中,~(137)Cs比活度较低,范围为0.10~5.94Bq/kg,平均值约为1.23Bq/kg。【结论】表层沉积物中,~(137)Cs含量相对陆地含量要低,主要原因可能是沉积物样品中含沙量大,~(137)Cs吸附量相对较少导致。同时,自然因素和人为活动对~(137)Cs在河口及海湾沉积物中的再分配起重要作用。     

Distribution characteristics of ^137Cs in wind-eroded soil profile and its use in estimating wind erosion modulus

~~Distribution characteristics of ~(137)Cs in wind-eroded soil profile and its use in estimating wind erosion modulus1.Tamura, T, Jacobs, D. G, Structural implications in cesium sorp-tion, Health Physics, 1960, 6(2): 391-398. 2.Rogowshi, A. S., Tamura, T, Movement of 137Cs by runoff, erosion and infiltration on the alluvial captina silt loam, Health Physics, 1965, 11(12): 1333-3340. 3.Owens, P. N., Walling, D. E., He, Q. P., The behaviour of bomb-derived caesium-137 fallout in …