Realistic retrospective dose assessments to members of the public around Spanish nuclear facilities

In the frame of an epidemiological study carried out in the influence areas around the Spanish nuclear facilities (ISCIII-CSN, 2009. Epidemiological Study of The Possible Effect of Ionizing Radiations Deriving from The Operation of Spanish Nuclear Fuel Cycle Facilities on The Health of The Population Living in Their Vicinity. Final report December 2009. Ministerio de Ciencia e Innovación, Instituto de Salud Carlos III, Consejo de Seguridad Nuclear. Madrid. Available from: http://www.csn.es/images/stories/actualidad_datos/especiales/epidemiologico/epidemiological_study.pdf), annual effective doses to public have been assessed by the Spanish Nuclear Safety Council (CSN) for over 45 years using a retrospective realistic-dose methodology. These values are compared with data from natural radiation exposure. For the affected population, natural radiation effective doses are in average 2300 times higher than effective doses due to the operation of nuclear installations (nuclear power stations and fuel cycle facilities). When considering the impact on the whole Spanish population, effective doses attributable to nuclear facilities represent in average 3.5 × 10⁻⁵ mSv/y, in contrast to 1.6 mSv/y from natural radiation or 1.3 mSv/y from medical exposures.     

Determination of concentration factors for Cs-137 and Ra-226 in the mullet species Chelon labrosus (Mugilidae) from the South Adriatic Sea

Concentration factors for Cs-137 and Ra-226 transfer from seawater, and dried sediment or mud with detritus, have been determined for whole, fresh weight, Chelon labrosus individuals and selected organs. Cesium was detected in 5 of 22 fish individuals, and its activity ranged from 1.0 to 1.6 Bq kg⁻¹. Radium was detected in all fish, and ranged from 0.4 to 2.1 Bq kg⁻¹, with an arithmetic mean of 1.0 Bq kg⁻¹. In regards to fish organs, cesium activity concentration was highest in muscles (maximum - 3.7 Bq kg⁻¹), while radium was highest in skeletons (maximum - 25 Bq kg⁻¹). Among cesium concentration factors, those for muscles were the highest (from seawater - an average of 47, from sediment - an average of 3.3, from mud with detritus - an average of 0.8). Radium concentration factors were the highest for skeleton (from seawater - an average of 130, from sediment - an average of 1.8, from mud with detritus - an average of 1.5). Additionally, annual intake of cesium and radium by human adults consuming muscles of this fish species has been estimated to provide, in aggregate, an effective dose of about 4.1 μSv y⁻¹.     

食物安全:基于食品系统理论的探讨

在经济发展、消费升级、资源短缺和环境问题凸显的新的外部环境背景下,本文引入了国外新兴的食品系统理论,探讨并提出了可持续的食物安全保障的新观念.食物安全始终是中国经济发展、社会稳定和国家自立的基础.国内多数学者仍然用30年前食物匮乏时期的思路来研究现代的食物安全问题,其结果导致研究结论与现实情况不符.如何在节约资源、减少浪费的同时又能够满足人们不断升级的食物消费需求,是对未来食物安全保障的新要求.本文首先分析了我国食物安全研究的现状,指出了不足和问题,然后引入国外新兴的食品系统理论,在探讨其概念内涵的基础上,剖析了食品系统与食物安全的关系,影响食物安全的因素和研究视角,并进一步提炼出基于食品系统理论的新的食物安全保障观念,为我国研究食物安全提供借鉴.     

中国省际能源效率差异及其影响因素分析

我国省际能源效率存在较大的差异.要进一步促进能源综合利用,需要在区域层面对能源效率差异形成的因素作更加全面深入的研究,以寻求更加合理有效的促进宏观能源效率改进的理论与方法.本文基于2007年的截面数据,运用能很好地消除各因素间多重共线性的偏最小二乘回归建模,选取了14个变量来代表经济发展水平、产业结构、工业结构、能源消费结构、对外开放程度、投资水平、政府影响力、制度因素、能源价格和地理因素这10个因素,分析了各因素对能源效率地区差异的影响方向和影响程度.研究结果表明,各地区固定资产投资中外商投资比重、工业增加值中高耗能产业比重以及煤炭消费比重的差异是造成能源效率地区差异显著的主要原因.这说明投资水平、工业结构和能源消费结构是造成能源效率地区差异显著的主要因素.要在短期内缩小地区间的能源效率差距,必须严格限制某些地区高耗能行业的过快发展,加强高耗能行业的结构调整,加快淘汰落后产能,大力提升煤炭的使用效率.     

耕地集约利用影响因素的协整分析

耕地利用的集约度实质上是农户在其所面临的各种经济和制度环境约束条件下,所采取的不同耕种行为的直接结果和体现.本文试借助分析影响农户耕种行为的相关因素来探讨其对耕地集约利用的影响.利用Eviews 6.0统计软件,综合应用协整理论和误差修正模型,以湖北省为例,剖析耕地集约利用与其影响因素的长期均衡关系和短期波动效应.研究表明:在长期,户均农业劳动力人数、农业比较收入和耕地的产权保障对耕地利用的集约度存在正向影响,其增加1个百分点,将导致耕地利用的集约度分别提高0.166、0.430和0.035个百分点;农民家庭人均农业生产支出和农业生产资料价格指数对耕地利用的集约度存在负向影响,其增加1个百分点,将导致耕地利用的集约度分别下降0.004和0.008个百分点.而在短期,各影响因素对耕地利用集约度的作用方向相同而作用力大小不同.户均农业劳动力人数和农业比较收入对耕地集约利用的作用程度在短期与在长期是相似的;但耕地的产权保障和农业生产成本的变化对耕地集约利用的影响却更多体现在长期.因此,立足于稳定产权和降低农业生产成本的农业政策导向更有利于在长期保护耕地,提高耕地资源的配置和利用效率.     

新疆阿克苏地区平原区高砷地下水分布特征及富集因素分析

地下水砷污染是全球化环境问题.本文基于阿克苏地区平原区2017年75个地下水砷实测含量进行分析.结果表明,研究区地下水砷含量变化范围为ND-98.70 μg?L-1,平均值为9.42μg?L-1,超标率达26.7％.水平方向上,高砷地下水主要集中在研究区的中部偏南一带;垂直方向上,山麓斜坡冲洪积砾质平原潜水区地下水砷含...     

考虑荷载修正的衬砌背后空洞对结构安全性影响分析

以云南省某公路隧道为背景,建立考虑空洞影响下的荷载-结构修正计算模型,引入最小安全系数,对衬砌安全性进行评估.计算结果表明:背后存在空洞时,衬砌受力条件恶化,空洞处衬砌内力重分布明显,弯矩分布形态发生改变,导致衬砌安全性显著降低.拱顶或拱腰背后存在空洞时,衬砌最小安全系数均随空洞范围变大而降低.相同空洞范围下,相较于拱...     

气象因素对输变电线路电磁环境的影响

不考虑气象因素的输变电线路的电磁环境预测值与实际值之间有差距,探讨了温度、湿度、风等气象因素对输变电线路电磁环境的影响,并提出减缓措施。结果表明:温度上升,则电磁场强度及无线电干扰强度都会增强;高相对湿度下电磁场强度与湿度成正比,低湿度则无明显影响,湿度对无线电干扰的影响与线路电压有关;风使输电线发生偏移,改变空间电磁场强度。     

电极移动速度效应检测仪系统的研究

分析了国际静电放电测试研究领域现有的各种测试研究装置特点，为克服已有测试装置缺陷本团队研发设计出一种全新的静电放电测试研究系统—电极移动速度效应检测仪。对其结构设计特点、功能进行了分析。我们研制的新型静电放电测试系统兼具实现真实直线运动准确调节和多环境因素可控的优点，彻底解决了困扰国际电磁兼容静电放电研究领域电极需高速向靶移动放电与避免强烈撞击损坏仪器的难题，实现了对多种因素影响逐一准确控制，为静电放电性质更为深入广泛的研究提供了新的手段和平台。     

Theoretical and Empirical Analysis on Influence Factors of Modern Agricultural Equipment Level in the Processof Agricultural Sustainable Development

To promote modern agricultural equipment level is one characteristic of constructing and developing modern agriculture in China.This paper makes up stepwise linear regression analysis model of influence factors of modern agricultural equipment level,and chooses rural labor,per capita income of rural residents,rural investment,proportion of people at secondary education level and at higher level in per hundred rural labor force and arable land area as independent variables,and total power of machine as induced variable.The major results show that the relativity of modern agricultural equipment level,rural investment and education level of peasants is remarkable,and they are the major influence factors of modern agricultural equipment level.Raising investment level of rural infrastructure construction as well as and research and development and promotion of advanced and applicable modern agricultural equipment,improving quality and education level of peasants can accelerate the development of China’s modern agricultural equipment effectively in the process of agricultural sustainable development.