Mortality and morbidity benefits of air pollution (SO2 and PM10) absorption attributable to woodland in Britain

Forests in Britain produce social and environmental benefits, in addition to marketable timber outputs. One such non-market benefit is the reduction in air pollution, linked to health impacts (mortality and morbidity). This study assesses the benefits of SO2 and PM10 absorption by trees in terms of extending life expectancy of the population and reducing hospital admissions. Working at a resolution of 1 km2 with woodland over 2 ha, it is estimated that, for Britain as a whole, woodland saves between 5 and 7 deaths, that would otherwise have been brought forward, and between 4 and 6 hospital admissions each year. The economic value of the health effect of woodland is estimated to be at least 900,000 pounds Sterling per year. Smaller areas of woodland, often located closer to population, sometimes strategically planted close to pollution sources, will generate additional air pollution absorption benefits to those estimated here. Researching such benefits would require more detailed data than is available at present for a national study. However, the health benefits of woodland are relatively small in comparison to other non-market forestry benefits.     

Water Companies' Service Performance and Environmental Trade-offs

Water companies have to ensure that supply and demand for water are kept in balance. This can necessitate the development of new sources of supply that may conflict with local wildlife interests. The paper reviews the policy background to this problem in the UK. It then presents an appraisal of a project to artificially recharge an aquifer with river water during the winter period, and abstract the water in the summer to augment shortages during drought conditions. The research investigates the preference trade-offs of water company customers between increasing security of supply and potential environmental impacts on local wetland sites and river flows. A cost-benefit analysis of the project is presented. The study also reveals a disparity between the site-specific valuation and that generated using the Environment Agency's approved benefit transfer guidelines.     

飞行器隔热瓦1200℃性能测试中接触热阻影响仿真与验证

目的 建立统一的飞行器隔热材料性能测试标准。方法 利用数值方法对飞行器隔热瓦1 200℃热环境性能测试中的传热模型进行计算。设计3种不同热导率和表面粗糙度的绝热材料隔热性能对比试验。在考虑接触面间凹凸点完全接触导热、接触间隙介质导热和相邻界面辐射传热联合作用时,能够获得与实测数据基本一致的计算结果。结果 试验证明,接触热阻是导致实测数据与理想传热结果相悖的主要原因。获得了接触热阻条件下热扩散系数随传热过程的变化关系,定量得到了相同测试条件下给定的3种不同热导率与粗糙度底部绝热材料对隔热性能测试结果的影响。结论 测试结果存在较大偏差的主要原因是表面粗糙度所致,两接触面在高温条件下更有利于热流传播。研究结果可为飞行器热防护系统设计与性能考核试验方案的确定提供重要参考依据。     

红壤中Cu、Zn、Pb 污染对蔬菜根伸长的抑制效应

采用盆栽试验,研究红壤中不同浓度Cu(0~400 mg/kg),Zn(0~750 mg/kg)和Pb(0~2000 mg/kg)对小白菜,包菜,萝卜,洋葱,番茄和黄瓜根生长的抑制与毒性效应.结果表明,蔬菜对金属的毒性响敏感程度依次是Cu>Zn>Pb.相同浓度下,Cu、Zn、Pb 对番茄和小白菜的根伸长抑制率最大,对黄瓜和萝卜的根伸长抑制率最小,表明番茄和小白菜对Cu、Zn、Pb 的毒性响应最敏感,黄瓜和萝卜则不敏感.蔬菜根长与土壤Cu有效态含量呈显著或极显著负相关(P<0.05, P<0.01),与土壤Zn 有效态含量或土壤Pb 有效态含量呈极显著负相关(P<0.01),表明土壤中重金属有效态含量是影响蔬菜根伸长的重要因素,重金属对蔬菜生长的抑制响应主要是通过有效态来实现.     

中国北方地区水体中四环素族抗生素残留现状分析

为了更好了解北方市政污水等水体中四环素族抗生素残留现状,采用固相萃取方法对中国北方地区市政污水样品进行富集和净化,以高效液相色谱-串联质谱法分析样品中四环素族抗生素残留量。在调查的13个污水样品中四环素族抗生素普遍检出,且浓度分别达到四环素1114.27ng/L、土霉素2175.65ng/L、金霉素149.09ng/L和强力霉素187.45ng/L。结果表明,在我国近岸污水排放中依然有大量四环素类抗生素存在,应加强对近岸海洋环境中抗生素残留的监测与管理。     

孔雀石绿对两种藻类的毒性

考察了孔雀石绿对小球藻(Chlorella pyrenoidosa)和金藻(Isochrysis zhan jiangensis)生长的影响,并研究了孔雀石绿对小球藻中叶绿素含量的影响.结果表明,孔雀石绿对两种藻类的生长具有较强的抑制效应,96 h的半抑制效应浓度(Ec50)分别为0.133 mg·l-1和O.017mg·l-1时属于高毒,而且对金藻的毒性大于小球藻.小球藻中叶绿素b和类胡萝卜素的含量随孔雀石绿浓度的增加而明显下降.     

弹箭外表面接插件高温高湿度耦合环境试验方法研究

目的 在地面条件下更真实地模拟弹箭外表面电器接插件在雨、雪、雾等高湿度条件下的飞行环境,方法利用数值分析方法,通过综合对比相同喷嘴结构下不同出口尺寸的外流场形态、不同压差下喷嘴出口流量等计算结果,确定喷口尺寸和工作压力.通过涡流黏度云图,确定接插件与喷嘴的相对位置关系.通过建模对喷淋方案进行效果预测后,搭建配套试验系统,并在石英灯加热器热辐射环境下开展高温高湿度耦合环境实效模拟试验.结果 试验中加热条件能够满足飞行过程中的表面温度及总加热量要求,水气环境模拟达到1.82 mm/min条件.试验后,对参试产品进行阻值测试、剖面碳化层厚度测量和热解产物分析,表征电气特性良好.结论 所述试验方法能够同时有效模拟高温高湿度飞行环境,能够对雨、雪、雾等高湿度条件下的接插件产品的飞行可靠性进行有效评估.     

中国近岸海洋和海岛环境中抗生素抗性基因的研究进展

抗生素在不同领域被大量使用甚至滥用,未被利用的抗生素会经过不同途径进入环境,导致抗生素抗性菌（antibiotic-resistant bacteria,ARBs）和抗生素抗性基因（antibiotic resistant genes,ARGs）广泛传播。ARGs作为新型环境污染物被广泛关注,成为全球性的环境问题。本文综述了中国近岸海洋与海岛环境中ARGs的赋存状况,分析了ARGs在海岛环境与近岸海洋环境中的赋存特征差异,并对海岛(海南岛)ARGs的研究提出建议。     

突发性气象灾害监测系统的设计

本文探讨了一种以新一代多普勒天气雷达为探测手段,应用GIS技术,借助Surfer等值线分析功能,获取灾害性天气落区、面积等定量化信息的方法,并据此以VB及VBA开发了一套突发性气象灾害监测系统,并给出了该系统一次典型冰雹过程的应用实例.