广州市土壤天然放射性水平调查

本文主要分析了广州市土壤天然放射性水平的调查数据。本次土壤氡浓度调查基本采用2km×2km的网格对广州市老八区均匀布点，采用GPS（卫星定位）定位。本次调查的结果表明：广州市的γ辐射剂量率平均值高于全国水平，是高放射性本底地区；氡浓度水平虽然在不同的季节变化较大，但两次不同季节的调查结果均与全国土壤氡平均值相当，属于中等水平。     

《天津市建筑材料放射性水平调查与研究》通过市建委鉴定

2003年3月26日 ,由天津市辐射环境管理所完成的《天津市建筑材料放射性水平调查与研究》通过了市建委组织的专家鉴定。课题研究目标是 :(1)天津市建造建筑物主体工程所使用主要无机非金属类材料的放射性水平(γ辐射剂量率、天然放射性核素比活度) ;(2)建筑物饰面装饰材料的放射性水平 ;(3)不同用途民用建筑物室内γ辐射剂量率和氡年均浓度 ;(4)地面装饰材料对居室内的γ辐射剂量率和氡年均浓度的影响及近些年来变化趋势。创新了一套快速、简便、经济实用的建材放射测量方法 ,具有推广前景。其应用领域为建筑材料生产与销售行业、建材行政管…     

覆土对渣堆氡析出率与伽玛辐射的影响试验

牦牛坪稀土矿的开发,对矿区及周围地区存在放射性污染问题。试验以牦牛坪的一个渣堆为研究对象,选择当地易取的亚砂土进行覆盖试验,研究不同覆盖厚度与氡析出率和γ辐射剂量率之间的关系,推荐最佳覆盖厚度。结果表明:覆土能降低渣堆的氡析出率和γ辐射剂量率,且厚度越大,氡析出率的降低系数越大。经综合分析,最终推荐最佳覆盖厚度为50 cm。     

覆土对渣堆氡析出率与伽玛辐射的影响试验

牦牛坪稀土矿的开发,对矿区及周围地区存在放射性污染问题。试验以牦牛坪的一个渣堆为研究对象,选择当地易取的亚砂土进行覆盖试验,研究不同覆盖厚度与氡析出率和γ辐射剂量率之间的关系,推荐最佳覆盖厚度。结果表明:覆土能降低渣堆的氡析出率和γ辐射剂量率,且厚度越大,氡析出率的降低系数越大。经综合分析,最终推荐最佳覆盖厚度为50 cm。     

新疆伊犁盆地南缘天然放射性水平评价

本文根据新疆伊犁盆地南缘1∶2.5万地面γ能谱测量中的铀、钍、钾含量数据,对新疆伊犁盆地南缘地表介质的天然放射性进行了研究和评价。测量结果显示,该地区地表介质中放射性核素²³⁸U、²³²Th和⁴⁰K的比活度,分别为6.14～2584.64 Bq/kg、2.86～105.63 Bq/kg、11.58～2190.83 Bq/kg。γ射线空气吸收剂量率均值为75.56 nGy/h,低于全国(81.50 nGy/h)和世界(80.00 nGy/h)的平均值;内、外照射指数和年有效剂量都在国家限量标准控制范围内。研究区局部放射性水平相对偏高,与含铀地层露头受自然动力和人类活动等作用下铀元素扩散有关;由于含铀地层露头规模有限,其对放射性环境的影响具有强度小、范围小、不均匀特征。     

铀辐射防护杂谈——兼谈华东地质学院实验楼辐射防护设计

铀是放射性很强的剧毒物质之一,人们在生产和使用铀的实践中,对其放射性射线的危害途径和如何防护其放射性射线对人体的危害,进行了深入而有效的探索。本文拟结合华东地质学院实验楼工程的铀矿物实验室、陈列室,铀矿床实验室、陈列室(简称铀矿实验室)的设计,谈点粗浅的看法: 一、铀γ、α射线对人体的危害性. 铀矿实验室陈列和使用的铀矿石标本,会辐射出穿透性很强的γ射线。如超过了人体的允许照射剂量,则将对人体产生不同程度的危害。铀矿标本和铀矿石,随着时间的推移而衰变,产生有放射性的氡气。氡进入大气又不断衰变产生放射性更强的氡子体。当实验室工作人员进行呼吸时,氡随空气由呼吸道进入     

刚果金某铜钴矿区天然放射性外照射估算

天然放射性辐射估算,是环境评价中判定天然放射性辐射水平的一项重要工作.文章介绍了一种矿区天然放射性外照射的估算方法,通过系统地采集矿区地层岩石样品并记录其采样位置,用低本底多道γ能谱仪对样品中的镭-226、钍-232、钾-40放射性比活度进行测量,换算得到外照射空气的吸收率,按采样点位绘制矿区放射性外照射空气的吸收率分布区图,按区估算出矿区及外围天然放射性外照射年有效剂量.     

我国石煤碳化砖房致居民集体有效剂量当量的估算

本文报导了我国石煤碳化砖的历年总产量及其放射性核素~(226)Ra、~(232)Th、~(40)K的比活度。估算了室内γ吸收剂量率和平衡氡浓度及这种建筑物施于居民的附加集体有效剂量当量。     

中国锦屏地下实验室空气氡浓度监测(2010—2011)

为评估中国锦屏地下实验室的氡本底辐射环境对稀有物理事件探测实验及极低本底伽玛能谱测量装置的影响,使用测氡仪对实验大厅的空气氡浓度进行了跨度为10个月(134d)的实时监测。监测数据显示:在无通风情况下,实验大厅空气氡浓度平均值为101Bq·m-3,波动范围为60~149Bq·m-3;在通风情况下,实验大厅空气氡浓度平均值为86Bq·m-3,波动范围为19~179Bq·m-3;与国际地下实验室相比,中国锦屏地下实验室的空气氡浓度处于平均水平,能够保证各低本底实验的正常运行。     

四川地区各类建筑物内γ辐射水平

本文报导了四川地区各类建筑物内的γ辐射水平。全地区共测了4050个点,γ辐射均值为(11.7±2.0)×10~(-8)Gy·h~(-1)。不同建筑的γ辐射水平,以煤渣砖房最高(14.7±3.8)×10~(-8)Gy·h~(-1),土墙房次之(13.3±2.0)10~(-6)Gy·h~(-1),木结构(10.3±2.0)×10~(-8)Gy·h~(-1)和水泥房最低(9.7±1.9)×10~(-8)Gy·h~(-1)。     

浅析高速公路工程招投标中的最低评标价法

结合目前高速公路施工项目招投标活动的实际情况,阐述了最低评标价法的概念,归纳了其优点及存在问题,对完善最低评标价法提出几点策略,以期促进招标投标市场更加规范有序。     

Place-Making in Megaprojects in Melbourne

This article analyses state-led place-making practices in Melbourne. The two levels of government that influence planning in Melbourne make much of the city as ‘culturally vibrant’ and ‘creative’, and have incorporated creative city-inspired place-making principles into many layers of the planning system. An examination of the development of two mixed-use megaprojects in central Melbourne reveals however that ideals of culturally engaging public places, and indeed of creative landscapes for middle-class consumption, wither in the face of more basic imperatives for economic development. In these case studies the ‘creative city’, no matter how the idea is interpreted, has little traction either as a set of inclusive place-making principles or as a gentrification strategy. The article concludes that the creative city-inspired place-making objectives in the planning system at both state and local levels are ambiguous in their overall intents and completely unsupported by statutory controls. Such place-making objectives as are realised are the compromised results of the interplay of uncoordinated decisions, delivered at the pleasure of the developer.     

Pathogens in septage in Vietnam

Septage is widely acknowledged as a major source of infectious pathogens while disposal of septage, and the operation and maintenance of septic tanks, is not regulated in many developing countries. Twenty untreated septage and septage sludge samples were taken from Can Tho City, Vietnam to examine their pathogen content, and indicator micro-organisms. Escherichia coli and Enterococcus spp. were detected in all samples, regardless of sludge storage time. Phages were detected in 80% of samples. Salmonella spp. were detected in 70% of the untreated septage and 60% of septage sludge samples. Concentrations of phages and bacteria tested in septage sludge after many years of tank storage were much higher than the expected levels. Helminth ova were present in 95% of untreated septage samples with an average of 450 ova l^− 1, and were detected in all septage sludge samples with an average of 16,000 ova l^− 1. Twelve varieties of helminth ova were identified. More helminth ova varieties in higher concentrations were found in septage than those reported from stool samples. The varieties' frequency ranged from 10% to 50% and Ascaris lumbricoides predominated. Results show that pathogens and indicator micro-organisms, especially helminth ova, accumulate in sludge. Thus helminth ova should be considered when septage sludge is treated and used for agriculture. Proper health protection measures must be applied for people handling septage.     

新时期广东城市化的新特点

新时期广东城市化出现以下特点:知识源导向、城市由单体向群体化发展、产业集群推动、政府主导自上而下的集约化发展、城镇化向城市化转变、由重“数量”发展向重“质量”发展的转变。     

浅谈建筑施工临时用电安全

针对由于建筑施工临时用电安全管理的不完善和不规范操作而导致大量工伤事故频频发生的问题,为消除用电安全隐患,对建筑施工临时用电安全管理进行了归纳和分析,并提出了整改意见,以确保现场人员及电气设备的安全运行。     

谈城市历史保护规划的误区

由于缺乏起码的历史文化知识,忽视历史文化遗产的保护,错误的决策导致了建设性的破坏,要加强城市保护的教育,培养合格人才。     

浅谈我国工程项目建设成本控制存在的问题

结合目前我国施工企业工程项目成本管理现状,对工程项目成本管理过程中存在的问题进行了较详细的分析,并提出了一些解决问题的办法,以做好项目成本控制工作,进而增强企业经济实力。     

Perchlorate exposure in lactating women in an urban community in New Jersey

Perchlorate is most widely known as a solid oxidant for missile and rocket propulsion systems although it is also present as a trace contaminant in some fertilizers. It has been detected in drinking water, fruits, and vegetables throughout New Jersey and most of the United States. At sufficiently high doses, perchlorate interferes with the uptake of iodine into the thyroid and may interfere with the development of the skeletal system and the central nervous system of infants. Therefore, it is important to quantify perchlorate in breast milk to understand potential perchlorate exposure in infants. In this study we measured perchlorate in breast milk, urine, and drinking water collected from 106 lactating mothers from Central New Jersey. Each subject was asked to provide three sets of samples over a 3-month period. The average ± SD perchlorate level in drinking water, breast milk, and urine was 0.168 ± 0.132 ng/mL (n = 253), 6.80 ± 8.76 ng/mL (n = 276), and 3.19 ± 3.64 ng/mL (3.51 ± 6.79 μg/g creatinine) (n = 273), respectively. Urinary perchlorate levels were lower than reference range values for women of reproductive age (5.16 ± 11.33 μg/g creatinine, p = 0.03), likely because of perchlorate secretion in breast milk. Drinking water perchlorate levels were ≤ 1.05 ng/mL and were not positively correlated with either breast milk or urine perchlorate levels. These findings together suggest that drinking water was not the most important perchlorate exposure source for these women. Creatinine-adjusted urine perchlorate levels were strongly correlated with breast milk perchlorate levels (r = 0.626, p = < 0.0005). Breast milk perchlorate levels in this study are consistent with widespread perchlorate exposure in lactating women and thus infants. This suggests that breast milk may be a source of exposure to perchlorate in infants.     

瓷砖放射性研究

通过对瓷砖放射性抽样检测,得到了瓷砖放射性质量状况,与过去检测数据相比较,初步研究发现放射性有增大的趋势。