复合防氡防辐射墙面腻子的研究

针对人类居住和工作环境中普遍存在的氡和放射性污染问题,利用重晶石、石膏、沸石以及高铝水泥和石灰等国内丰富的矿产资源开发各种具有防氡防辐射的功能微集料作为基元材料,研制成功了具备防氡防辐射的双防功能的墙面腻子。在基元材料添加量为20％的情况下,采用表面析出法测得该墙面腻子对氡的屏蔽率为86．5％,对射线的屏蔽率为48．4％。     

防氡防辐射墙体腻子的研究

介绍了用滑石粉做基材 ,添加适量掺和料重晶石或沸石材料 ,研制可吸收墙体中氡气及其子体产生的辐射的墙体腻子。研究表明 :沸石的防氡性能比重晶石好 ,添加 2 0 %沸石时防氡率为 46.1% ;重晶石的防辐射性能好于沸石 ,添加 2 0 %重晶石时 ,内照射指数为 0 .10mSv。通过提高掺合料细度可较好地提高防氡防辐射的效果。     

生态复合功能涂料在四川研制成功

由四川西南科技大学教授董发勤丰持研究的863项目“生态复合功能涂料开发”、“防氡防辐射砌筑水泥／腻子／涂料及其复合体的开发”日前通过了四川省科技厅有关专家的鉴定。     

氡的危害及防氡建筑涂料

介绍了氡的逸散来源、对人体的危害及防氡建筑涂料的生产和性能。     

新型环保防氡涂料中消泡剂用量的探讨

目前,室内氡治理日益得到重视。为了更好地降低室内氡浓度,作者研发了一种新型环保防氡涂料。在该涂料的研发过程中,作者特别就其设计思路,以消泡剂为例进行了探索,并成功地解决了消泡与防氡、环保功能的互相协调问题。     

微纳米薄层石墨基水性防氡涂料的制备及其性能研究

首先制备了一种微纳米薄层石墨浆料,然后以苯丙乳液为成膜基料,配以玻璃粉、绢云母及其他颜填料和助剂,制备了一种微纳米薄层石墨基水性防氡涂料。研究发现,微纳米薄层石墨浆料的添加量以3%为宜,此时涂料的防氡效率达到92.7%,涂料颜色对其防氡效率无影响;紫外光老化时间达400 h时,涂料的防氡效率仍可达到92.3%,防氡性能长效稳定。     

氡的危害及防氡建筑涂料

介绍氡的逸散来源、对人体的危害及防氡建筑涂料的生产和性能。     

粉煤灰/煤渣砖氡污染防治的研究

采用重钙粉和聚乙烯醇水溶胶作为粉煤灰/煤渣砖的防氡材料,通过正交试验,以氡屏蔽率和抗压强度为评判指标,对粉煤灰/煤渣砖氡污染防治进行了研究。结果表明,水泥与重钙粉对氡释放量影响很大,粉煤灰和煤渣影响相对较小,煤渣、粉煤灰掺量增加,氡浓度总体上也随之增大;当重钙粉掺量增大,氡释放量降低明显;而聚乙烯醇水溶胶的用量少,对氡释放量的影响较小。加入30%重钙粉与3.0%聚乙烯醇水溶胶的砖块氡屏蔽率最高可达49.36%,抗压强度也明显提高。SEM分析表明,加入重钙粉和聚乙烯醇水溶胶,粉煤灰/煤渣砖内部大颗粒之间及表面被细小颗粒填充覆盖并相互粘合,提高了密实度,并在外表面形成致密结构,使得氡析出路径曲折,从而达到了屏蔽氡的目的。     

氡及居室氡污染

1　氡在自然界的分布氡是一种无色无味的惰性气体。是放射性元素铀、钍等衰变链的一个产物 ,是天然放射性铀系中的一个放射惰性气体 ,它具有极强的迁移活动性 ,凡有空气的空间就有氡及其子体的存在。在自然界 ,氡没有稳定的同位素 ,只有三种天然放射性同位素2 2 2 Rn2 2 0 Rn、2 19Rn。地壳及大气中均含有氡 ,它可以在特定的土壤、地下水和建筑物内富集。地壳中氡平均含量为 3× 1 0 -6,大陆表面的空气中氡平均含量为 1 0 -10Ci/m3 ,海洋表面平均含氡 2 .9× 1 0 -12 Ci/m3。离大陆和海洋表面越远 ,氡在空气中的含量越少。氡能溶解于水和…     

用氡室连续测量涂膜阻氡率方法及其算法

为解决在测量涂膜阻氡率时带来的环保、经济、重复利用氡源、连续测量寻找体系平衡态等问题，在本测量系统中设计了利用廉价易得的铀矿粉作为氡源的氡室。采取以不锈钢丝网为骨架制作无衬底涂膜样板，消除衬底在测量涂膜阻氡率时带来的影响。运用统计物理学原理，找出涂膜影响氡室内的氡浓度和集氡室内的氡浓度的规律，从而推导出了一种反映涂膜阻氡率的算法。提出了涂料阻氡性能新的表示方法；提出了一个新的物理量 ——Pδ值（防氡值）。研究结果表明：用氡室测量涂膜阻氡率方法及其算法是可行的，可作为测量涂膜阻氡率的通用标准方法，还可作为涂膜等薄膜的隔氧性能的测量方法。     

氡的危害与防护

氡是自然界唯一一种具有放射性的气体元素,研究其对人的危害与防护具有重要意义.介绍了氡的危害途径与方式,详细分析了日常生活中氡的主要来源,讨论了氡衰变特点建立的测量方法与技术,根据氡的特点与来源建议了室内氡的防护方法.     

室内放射性污染物氡危害及防治对策

主要对室内环境中氡的来源、危害做出详细的介绍。针对于室内氡的来源,提出了有效降低室内氡的措施。     

The Cellular and Molecular Carcinogenic Effects of Radon Exposure: A Review

Radon-222 is a naturally occurring radioactive gas that is responsible for approximately half of the human annual background radiation exposure globally. Chronic exposure to radon and its decay products is estimated to be the second leading cause of lung cancer behind smoking, and links to other forms of neoplasms have been postulated. Ionizing radiation emitted during the radioactive decay of radon and its progeny can induce a variety of cytogenetic effects that can be biologically damaging and result in an increased risk of carcinogenesis. Suggested effects produced as a result of alpha particle exposure from radon include mutations, chromosome aberrations, generation of reactive oxygen species, modification of the cell cycle, up or down regulation of cytokines and the increased production of proteins associated with cell-cycle regulation and carcinogenesis. A number of potential biomarkers of exposure, including translocations at codon 249 of TP53 in addition to HPRT mutations, have been suggested although, in conclusion, the evidence for such hotspots is insufficient. There is also substantial evidence of bystander effects, which may provide complications when calculating risk estimates as a result of exposure, particularly at low doses where cellular responses often appear to deviate from the linear, no-threshold hypothesis. At low doses, effects may also be dependent on cellular conditions as opposed to dose. The cellular and molecular carcinogenic effects of radon exposure have been observed to be both numerous and complex and the elevated chronic exposure of man may therefore pose a significant public health risk that may extend beyond the association with lung carcinogenesis.     

民用建筑工程室内环境中氡气的来源、危害及防护

文章介绍了氡的地球化学性质及危害,并以几年来对大量民用建筑工程室内环境污染物实测资料为依据,论述了室内环境中氡的危害、来源及应采取的防护措施。     

γ辐射和高温对放射性废物水泥固化体强度的影响(英文)

为了处理高活性、放热性C级放射性废弃物,在比利时通常采用圆柱体混凝土＂超级容器＂作为基本途径。＂超级容器＂是合成的废弃物包,废弃物由碳钢包裹组成,碳钢被波特兰水泥制成的＂缓冲器＂包裹。自密实混凝土作为一种特殊类型的混凝土,正被考虑用来制备＂缓冲器＂。一旦＂缓冲器＂被浇筑并且硬化程度很高时,放射性废弃物就被包裹在＂缓冲器＂内,存在的缝隙可以采用新拌灌浆料填充（例如自密实砂浆）。用盖子将＂超级容器＂密封后应用于＂超级容器＂的混凝土层,即混凝土缓冲器、灌浆料及盖子在硬化期间（灌浆料）与硬化之后（＂缓冲器＂与盖子）将暴露在废弃物热场与辐射场内。因此,需要解决2个主要的问题：1）γ射线（α与β射线被碳钢包裹层阻断,中子的影响可以忽略）对灌浆料硬化强度的影响;2）温度升高（从20℃升高到105℃）对硬化试件强度的影响。为了证实强度是否损失并确定强度损失后的主要机理,采用荧光显微镜,在砂浆或混凝土薄片的截面上直接分析毛细孔隙率。     

Trapping of Radioactive Inert Gas Radon on an Oxide Glass: Scintillating Glass Fiber Bundle Method

Two macroporous fiber bundle radon sensors were developed by close-packing the 50 m fibers drawn from scintillating oxide glass in the quartz tubes. Radon (²²²Rn) diffuses from the source, through these sensors in parallel or in series, to the end of the linear closed system filled with air under ambient temperature and pressure of 290.15 K 307.95 K and 760 Torr, respectively. The strategy is to provide radon atoms and alphas emitted from radon and its progeny with large accessible scintillating glass surface areas for efficient trapping and detection, respectively. The variations of count rates over 115 days indicate both the significant trapping of radon on the glass surfaces as well as the dependence of this trapping process on temperature.     

Polymer characteristics and fracture morphology of radiation-polymerized methyl methacrylate-impregnated mortar

Normal portland cement mortar–PMMA composites have been prepared under different doses of Co-60 gamma irradiation. The polymerization characteristics of MMA inside mortar and in bulk, mechanical and durability properties, and fracture morphology of the composites have been studied. The rate of in situ polymerization has been found to be faster than that in bulk. The molecular weights of the in situ and bulk PMMA were greatly reduced when a relatively higher dose of radiation was employed for the polymerization. However, the molecular weight of the PMMA-bulk was found to be higher than that of PMMA-in situ. The flexural/compressive strength and chemical durability in dil·H₂SO₄ medium of mortar–PMMA composites were, in general, superior to those of mortar–PS, though they declined under prolonged exposure to gamma irradiation. SEM micrographs of the fractured surface of the composites suggest a strong mortar–PMMA interfacial bonding and varied texture of the imbibed polymer in the matrix.