SD -3A测氡仪观测故障及解决方法

以河源4#SD - 3A测氡仪观测原理、运行性能为研究对象,结合几年来所发生的观测故障状况,在观测及维护过程分析SD -3A测氡仪故障原因,对测氡仪发生故障时采取相应的解决方法,进而熟练掌握测氡仪观测特性并及时解决实际操作难题.     

空气中氡浓度的测量及不确定度分析

本文总结了空气中氡浓度的测量方法及注意事项、控制标准,重点结合本单位的RAD7测氡仪对空气中氡浓度测量的不确定度进行了分析及计算,最后指出该测氡仪达到GB50325-2001中对空气中氡检测方法的测量不确定度的要求.     

南昌台气氡异常核实

前兆观测资料异常产生的原因总体可分为两大类:观测物理量自身变化和外部因素影响,后者即通常所称的干扰.要提取出观测资料中有价值的震兆信息,必须首先将干扰剔除,但由于前兆干扰成因本身具有复杂性和多样性,并随不同测项、不同环境而存在个体差异,故要求异常核实工作深入、细致、全面、客观.本文通过一个实例,详细介绍了异常核实的思路和流程,并确定此次异常为仪器干扰,不属于震兆异常.     

一种土壤氡浓度测量方法的改进

通过对CDI-2000土壤测氡仪的排气方式和测量周期的分析,建立了新的测量方法。既充分利用了CDI-2000自动换片、自动抽气的优点,又在不影响测量精度的情况下提高了工作效率,节约了工作成本。     

室内氡浓度与建筑材料表面氡析出率的关系研究

采用RAD7测氡仪对某8层教学楼第5层的房间进行24 h连续测定,测得室内氡浓度范围为5.65~48.7 Bq/m3,不超标。测定结果表明,清晨氡浓度较高,在5:00左右氡浓度达最高值;中午氡浓度较低,11:00左右氡浓度达最低值。经测定房间内墙面抛光瓷砖的表面氡析出率大于地板砖的表面氡析出率。房间室内的氡主要来源于建筑材料表面氡的析出和室外空气,利用氡析出率和室外氡计算的室内氡浓度与测定结果相符。     

我国六省人防工程氡浓度调查及影响因素初探

采用美国SUN公司的1027型测氡仪测得我国内蒙、山东、河南、湖北、湖南、广西6省共8个城市地下人防工程内的氡浓度,最高值为547.6 Bq/m3,最低值为22.2 Bq/m3.从地质背景、地下水、通风情况等五个方面讨论了氡浓度的影响因素,并提出主要影响因素为通风情况.     

RAD7测氡仪标准条件下不确定度的研究

研究RAD7测氡仪对空气中氡浓度测量的不确定度;通过标准氡室模拟不同的氡浓度,对该测氡仪在标准条件下测量的不确定度进行研究;取包含因子k=2时,在模拟的两种氡浓度情况下得到的该测氡仪不确定度分别为14.38%和14.52%;该测氡仪达到GB50325-2001中对空气中氡检测方法的测量不确定度的要求。     

我国六省人防工程氡浓度调查及影响因素初探

采用美国SUN公司的1027型测氡仪测得我国内蒙、山东、河南、湖北、湖南、广西6省共8个城市地下人防工程内的氡浓度,最高值为547.6 Bq／m3,最低值为22.2 Bq／m3。从地质背景、地下水、通风情况等五个方面讨论了氡浓度的影响因素,并提出主要影响因素为通风情况。     

银川台小口子泉水氡对比观测实验研究

本文以小口子泉模拟水氡观测为基础进行日常观测实验.通过加密观测、升高鼓泡水温和降低鼓泡水温实验,认为小口子泉水氡与泉点气温、鼓泡水温变化有关;不同的鼓泡水温对观测氡值有一定影响,但是影响幅度不大.通过不同的观测仪器对比实验,发现不同的观测仪器之间存在系统误差,但不影响观测资料的正常变化形态和幅度.两次实验可以为台站观测人员和分析预报人员掌握观测资料动态变化的影响因素、剔除非地震异常干扰提供帮助.     

固体径迹探测器与RAD-7测氡仪测定民用建筑工程室内氡浓度的比较

民用建筑工程室内氡的监测方法很多,其中固体径迹探测器法属于国标方法,RAD-7测氡仪法为近年来引进的仪器监测方法。本文对两种方法进行了比较,包括监测方法及原理、比对试验,并分析了2种方法的相关性、一致性和精度,以及两者在民用建筑工程室内氡验收监测的实际应用中的优缺点等,结果表明:以上两种方法从技术角度上讲,各有优点,均能满足一般室内空气中氡浓度的监测要求,虽然可利用固体径迹探测器法累积测量的结果来估算居住者受照剂量,进而评价氡的辐射危害,但因检验周期(至少30 d)过长,所以不适宜于工程检测;比较而言,RAD-7测氡仪的配置参数和测量方式更适宜于民用建筑工程的室内氡监测,已成为目前监测的主要方法,但在实际监测中,还需注意合理设置足够长的采样时间、湿度控制在10%以下、气路中残留气体的冲洗净化以及当初测值接近或超过《规范》规定的限量值时,有必要进一步延长监测时间进行跟踪监测等事项,以保证监测结果准确可靠。     

辽宁省部分城市室内氡浓度水平

对辽宁省 7个市区的办公室和居室内空气氡浓度水平进行了调查研究 ,结果表明 ,办公室室内空气中氡的平衡当量浓度为 3 9.3 / Bq· m- 3。居室空气中氡的平衡当量浓度为 43 .2 / Bq·m- 3,居民由室内氡及其子体所致年有效剂量为2 .6m Sv     

抽水蓄能电站建设中注意防止氡污染

针对某抽水蓄能电站地下勘探平洞检测氡气浓度超标问题,分析氡污染危害,提出防止氡污染的措施。     

室内氡污染的控制方法

介绍了消除氡源、控制氡源、通风和空气净化等现有房屋室内氡污染的防治方法,以及控制未来房屋内氡污染的方法。     

贵阳地区氡浓度的连续观测

叙述用静电累积氡测量仪对贵阳地区环境氡浓度进行连续四年的观测，氡浓度季节性的变化受气温、降雨量等因素的影响较大，降雨不仅可使环境氡浓度降低，而且在降雨量相近的情况下降雨次数较多氡浓度也会相对偏低。     

哈尔滨市部分新装修住宅室内空气质量的检测与评价

大量含有有害物质的装修材料的应用是引起室内空气污染的主要原因之一,经过对哈尔滨市内部分新装修住宅室内空气污染状况调查后发现,游离甲醛和总挥发性有机物均存在不同比例的超标现象。本文采用客观指数评价方法对新装修住宅的室内空气质量进行了评价,评价结果显示,48％的住宅室内空气质量符合卫生标准。     

高层建筑、建筑材料与室内氡污染

对高层建筑连续一年的室内氡浓度监测分析，发现室内氡浓度与建筑材料，建筑结构以及人们的生活习惯密切相关。     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.