内蒙古包头放射性废物库安全运行25年

文章简要论述了内蒙古包头放射性废物库现状、扩建工程及环境整治工程概况,通过对库区、库外辐射环境质量监测,放射性处于一般环境水平,废物库运行20多年来,未对周围环境造成污染,通过整治工程的建设,达到了预期治理要求,废物库运行是安全的。     

我国辐射环境自动监测系统建设的回顾与展望

辐射环境自动监测是我国辐射环境监测工作的重要内容,是核与辐射安全监管工作的重要手段.本文回顾了“十一五”以来,我国辐射环境自动监测系统建设的进展情况和在核与辐射监管工作中所发挥的作用,总结了辐射环境自动监测系统的建设和运行经验,并对今后的工作进行了展望,提出了完善系统建设和运行的合理化建议.研究指出,作为国家辐射环境监测网的重要组成部分,辐射环境自动监测系统初步具备了对我国省会城市和主要地级城市的辐射环境质量状况的实时监测能力.但由于我国辐射环境自动监测站于2008年底才开始在全国范围内建设,起步较晚、经验不足,依然存在点位数量和代表性不够、自动化程度不够高、软件系统功能不成熟、标准化和规范化问题比较突出,缺乏质量控制技术、运行维护难度大等问题.为此本文提出：第一,增加自动监测站数量,点位布设更有针对性;第二,增加自动监测站的类型;第三,加强软件系统的分析和控制能力;第四,完善相关标准、技术规范和质保体系;第五,完善运行维护体系;第六,增强国际学习和交流.     

深圳市天然γ辐射空气吸收剂量率调查

从2007年至2011年在深圳市进行了天然γ辐射空气吸收计量的调查.调查结果显示：全市天然辐射外照射空气吸收剂量率的变化范围为（4.87 ～17.68）×10^ 8Gy/h,平均值为10.00 ×10^ 8Gy/h,与广东省平均水平相当,稍高于全国平均值,属于正常天然本底范围;天然辐射外照射致深圳市居民人均年有效剂量当量（0.22 ～ 1.08） mSv,低于广东省与全国的平均水平;集体有效剂量当量54.32×10^2man· Sv.     

紫外辐射对小分子有机酸化学凝聚性作用途径探讨

通过烧杯实验系统考察了紫外辐射对脂肪羧酸类和酚酸类小分子有机酸的化学凝聚性的作用途径.结果表明,溶液pH对柠檬酸、草酸、酒石酸和丁二酸等脂肪羧酸类有机物的混凝性能影响较小.紫外辐射处理后,脂肪羧酸类小分子有机物的混凝去除率均高于未经紫外辐射处理的水样.进一步研究表明,紫外辐射过程中发生了光化学反应,使得脂肪羧酸的表面负电性降低,进而提高了其化学凝聚性.与脂肪类小分子有机酸不同,苯酚、水杨酸和苯甲酸的化学凝聚性较差,且受紫外辐射过程的影响小.单宁酸的混凝性能较好,pH=6时的去除率最高可达90%以上,这可能与其分子中脂肪酸碳链结构的存在以及单宁酸分子较大,易与PACl的水解产物发生吸附电中和反应有关.     

铀尾矿库尾矿砂大气污染的控制研究

铀尾矿库运行期间,裸露的尾矿以扬尘形式对周边地区造成环境污染和辐射危害.因此,本文以平地型铀尾矿库为对象,应用CFD技术,探讨滩面形状(弧形、棱形和锥形)对减轻或控制运行期间尾矿库滩面颗粒物的大气迁移和环境污染的作用.结果表明,常年主导风速V=1.0m·s-1条件下,以1 mg·m-3的浓度为抑尘标准时弧形滩面抑尘效果最为明显,棱形滩面和锥形滩面抑尘效果较差.通过对不同风速下几种滩面形状防护效果的分析对比发现,小风速(V=0.5 m·s-1)下3种滩面形式辐射防护均效果良好,但随风速的增大效果逐渐减弱;弧形滩面条件下综合防护效果最佳.     

In field arsenic removal from natural water by zero-valent iron assisted by solar radiation

An in situ arsenic removal method applicable to highly contaminated water is presented. The method is based in the use of steel wool, lemon juice and solar radiation. The method was evaluated using water from the Camarones River, Atacama Desert in northern Chile, in which the arsenic concentration ranges between 1000 and 1300 μg L⁻¹. Response surface method analysis was used to optimize the amount of zero-valent iron (steel wool) and the citrate concentration (lemon juice) to be used. The optimal conditions when using solar radiation to remove arsenic from natural water from the Camarones river are: 1.3 g L⁻¹ of steel wool and one drop (ca. 0.04 mL) of lemon juice. Under these conditions, removal percentages are higher than 99.5% and the final arsenic concentration is below 10 μg L⁻¹. This highly effective arsenic removal method is easy to use and inexpensive to implement.     

Ce(Ⅲ)对UV-B辐射胁迫下大豆幼苗光化学反应的影响

用水培法研究Ce(Ⅲ)对UV-B辐射胁迫下大豆幼苗光化学反应的影响.结果表明, 20 mg·L^-1 CeCl₃使大豆幼苗净光合速率(Pn)、Hill反应、Mg²⁺-ATPase活性与光合磷酸化活力4项指标较对照提高23.2%～14.3%; 有效抑制UV-B辐射(T₁=0.15 W·m^-2和T₂=0.45 W·m^-2)胁迫下4项指标下降, 4项指标降幅［Ce(Ⅲ)+T₁为36.6%～15.9%,Ce(Ⅲ)+T₂为65.6%～33.2%］小于对应的UV-B辐射组(T₁为50.9%～23.3%,T₂为77.3%～51.4%). 动态变化显示, Ce(Ⅲ)减缓了胁迫期4项指标的下降趋势,促进了恢复期4项指标上升幅度. 说明Ce(Ⅲ)通过减轻UV-B辐射对大豆幼苗光化学反应的伤害, 遏制UV-B辐射胁迫下大豆幼苗Pn下降.     

An efficient technology to treat heavy metal--lead--contaminated soil by microwave radiation

Microwave (MW) technology can be used to vitrify contaminated soil wastes and immobilize heavy metal ions in soils. More than 93% of the Pb(II)-contaminated soil was vitrified to a glass/ceramic formation after 30 min of MW radiation. In a 6-year study, the Pb(II) concentration of the vitrified soil in the leaching test was less than 1.0 mg/l, which is substantially below the USEPA regulatory limit of 5.0 mg/l.     

Effects of cerium on growth and physiological mechanism in plants under enhanced ultraviolet-B radiation

Effect of cerium （Ce^3＋） on the growth, photosynthesis and antioxidant enzyme system in rape seedlings （Brassica juncea L.） exposed to two levels of UV-B radiation （T1： 0.15 W/m^2 and T2：0.35 W/m^2） was studied by hydroponics under laboratory conditions. After 5 d of UV-B treatment, the aboveground growth indices were obviously decreased by 13.2%-44. 1%（T1） and 21.4%-49.3% （T2）, compared to CK, and except active absorption area of roots, the belowground indices by 14.1%-35.6%（T1） and 20.3%-42.6% （T2）. For Ce＋UV-B treatments, the aboveground and belowground growth indices were decreased respectively by 4.1%-23.6%, 5.2% -23.3%（Ce＋T1） and 10.8%-28.4%, 7.0%-27.8%（Ce＋T2）, lower than those of UV-B treatments. The decrease of growth indices appeared to be the result of changes of physiological processes. Two levels of UV-B radiation induced the decrease in chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency by 11.2%-25.9%（T1） and 20.9%- 56.9%（T2）, whereas increase in membrane permeability and activities of antioxidant enzymes including superoxide dismutase（SOD）, catalase （CAT） and peroxidase （POD） by 6.9%, 22.8%, 21.5%, 9.5%（T1） and 36.6%, 122.3%, 103.5%, 208.9%（T2）, respectively. The reduction of the photosynthetic parameters in Ce＋UV-B treatments was lessened to 3.2%-13.8%（Ce＋T1） and 4.9%-27.6%（Ce＋T2）, and the increase of membrane permeability and activities of antioxidant enzymes except POD in the same treatments were lessened to 2.4%, 8.4%, 6.6%（Ce＋T1） and 30.1%, 116.7%, 75.4%（Ce＋T2）. These results indicate that the regulative effect of Ce on photosynthesis and antioxidant enzymatic function is the ecophysiological basis of alleviating the suppression of UV-B radiation on growth of seedlings. Furthermore, the protective effect of Ce on seedlings exposed to TI level of UV-B radiation is superior to T2 level.     

通风口高度对太阳能烟囱建筑自然通风和自然排烟性能的影响研究

安装太阳能烟囱后的建筑具有效果优良、节能环保的自然通风系统。室内通风口高度是太阳能烟囱建筑性能的关键参数之一。提出通过改变太阳能烟囱建筑室内通风口高度位置,使太阳能烟囱既可用于建筑的日常自然通风,也能实现室内火灾场景下的自然排烟。利用缩比例实验台研究了不同室内通风口高度对太阳能烟囱建筑自然通风与自然排烟效果的影响,发现自然通风和自然排烟效果随通风口高度增加呈现先增大后减小的趋势,且最佳室内通风口高度位于窗户上檐位置附近。研究结果对太阳能烟囱建筑的建筑结构关键参数设计具有指导意义。