暴露组及其研究方法进展

过去20年中,基因组学的研究成果未能对疾病发生原因提供本质的认识,人们较早意识到环境因素对于人体健康的重要性.早期对于人体暴露的研究主要集中在内外暴露的研究,未综合考虑人体总的环境暴露.自暴露组(exposome)概念提出以来,得到了广泛关注,也使暴露科学的内涵和外延得到了延伸.暴露组是指一个人从出生至生命结束全过程各种暴露的总和,真正意义上探讨污染暴露、人体健康和疾病发生的实在本质,包括了外暴露、内暴露和社会暴露.研究方法上结合了基于生物监测的"自上向下"法和基于监测空气、水和食物等"自下向上"法,而在研究手段上涉及了环境科学的外暴露和基因组学的分子生物学等中广泛应用的研究技术.然而当前准确测量暴露组仍然是一个巨大的挑战,只有多学科技术手段和研究方法发展和融合才能更好地促进暴露组研究的进步.我国暴露科学研究起步较晚,目前学者对于暴露组的研究仍然薄弱,本文主要从暴露组的概念、研究方法以及测量技术手段入手,介绍这一新兴的研究科学.     

自然灾害遥感应用标准体系构建方法研究

遥感技术不仅能用于获得自然灾害发生之前的背景数据,而且可用于对自然灾害进行监测预警和损失评估,近年来已经成为自然灾害信息获取与分析的重要手段。标准体系构建是开展自然灾害遥感技术标准化应用的一项重要基础性工作,亟需研究和建立满足自然灾害管理需求的遥感技术应用标准体系。对国内外遥感技术标准特别是自然灾害遥感应用相关标准现状进行了综述。分析了自然灾害遥感技术应用标准化需求,探讨了标准体系构建的思路,提出了面向自然灾害遥感技术应用的并列式、串联式和混合式标准体系构建方法和洪涝灾害遥感监测关键技术标准需求。     

基于电磁混响技术的电磁环境与自然环境综合试验技术

目的研究电磁环境与自然环境综合试验方法。方法针对装备电磁环境与温度、湿度环境的多物理场综合试验需求,基于电磁混响技术,解决不同环境模拟相容性问题,对关键部件进行分析和设计,并依据相关标准进行了性能测试。依据IEC61000-4-21,分别测试电磁环境与自然环境综合箱在常温、高温和低温条件下的场均匀性。结果综合场均匀性偏差最大值小于3 d B,性能满足标准要求。结论基于电磁混响技术的综合试验方法,为装备在多重环境应力综合作用下效应机理研究和适应性考核提供了手段。     

无机沉淀对土壤有机质吸附疏水有机污染物的影响

土壤有机质对疏水性有机污染物的吸附解吸是影响其在土壤中迁移、转化和归趋的重要因素之一。老化是有机污染物和土壤等介质长时间相互作用的结果,它影响着污染物的生物有效性。已有的老化研究注重有机污染物被土壤等介质吸附隔离的机制,很少考虑土壤等吸附剂自身演化对有机污染物吸附的影响。本文通过无机沉淀处理方法来模拟自然环境过程吸附剂自身的演化对土壤有机质吸附能力的影响,从而证明吸附剂自身的变化也是影响老化效应的一个重要因素。结果表明,不同无机沉淀包裹和填充的碱提土样品比原始碱提土样品具有更小的吸附能力,同时无机沉淀处理后的样品的吸附性能随着无机沉淀离子浓度增加而降低。这可能是无机沉淀覆盖碱提土样品的内外表面积和填充碱提土样品的微孔所引起的,同时也可能是无机沉淀占据了吸附有机污染物的高能点位所致。     

管道压力对天然气射流火热辐射灾害的影响

天然气管道时常受到破坏,并诱发巨大的射流火焰,可能引燃周围建构物体。系统地分析了管道压力对天然气射流火热辐射灾害的影响,以建立天然气射流火热辐射灾害的系统定量分析方法。基于压力管道小孔泄漏模型和权重-多点源热辐射计算模型,建立了目标物体最大入射热辐射通量、管道压力和目标物与泄漏小孔水平距离的定量关系式。进而选定10 k W/m~2和31.5 k W/m~2作为城镇建筑物遭受引燃和机械破坏的热辐射通量阈值,得到了不同管道压力下天然气射流火热辐射灾害范围。计算结果表明,GB 50028—2006《城镇燃气设计规范》依据管道压力所规定的燃气管道与建筑物的安全间距不能完全满足天然气管道破坏时射流火焰的安全要求,与某武汉天然气管道射流火事故后果一致。     

Sensitive issues in natural resource management and discursive strategies addressing them

In natural resource management facilitation literature, little attention is paid to sensitive issues in multi-stakeholder interaction and learning. This article aims to fill this gap. It discusses the variety of discursive strategies used by stakeholders to address sensitive issues with regard to fishery management in Benin, in three different settings: individual interviews, homogeneous groups' discussions, and a heterogeneous group meeting. Issues that proved sensitive were discussed openly in the interviews or homogeneous groups' discussions, but not at all, or only indirectly, in the heterogeneous group meeting. With indirect discursive strategies, two out of the seven sensitive issues were put on the discussions' agenda. We conclude that the other issues were too sensitive among others because of historically grown interdependency between interventionists and fishers. We suggest that dealing with sensitive issues is an important dimension of the facilitation of interactive learning processes and provide methodological guidelines to detect and address such issues.     

Variation of reservoir fluid property during the high pressure air injection process

This research aimed at determining the variation of reservoir fluid property during the high-pressure air injection process. For this purpose, the forward multiple contact experiment was employed by pressure–volume–temperature (PVT) system to investigate the physical property variation of the crude oil and the complex oxidation reactions. The results show: under the relative low temperature and pressure condition, instead of carbon dioxide, carbon monoxide dominates the products in the air phase. The gas/oil ratio and volume ratio increased due to the generated gas while the viscosity and density achieved a descending trend. The colloid and bitumen in the oil phase reduced by half but the amount of wax achieved a small increase. The low-temperature oxidation and pyrolysis reactions caused the fluctuated change of the different compounds. The amount of light compounds decreased at the beginning and then increased while that of heavy compounds showed the opposite trend. But at last, due to the H/C ratio, the light compounds increased to more than their initial value.     

有风条件下室内火灾自然排烟模型试验研究

采用缩尺度试验方法对有风条件下室内火灾自然排烟过程准稳态进行研究,分析不同补气口、排烟口位置和风向对排烟效果的影响。试验结果表明:将补气口设在迎风面,排烟口设在背风面或侧风面时将获得比没有环境风时更好的自然排烟效果;而在其他情况下,环境风将通过减小排烟口处内外压差以及对室内烟气层产生扰动来降低自然排烟效果。在设置建筑自然排烟系统时,应综合考虑火灾具体情况以及当地风速条件,选择对自然排烟有利的排烟口与补气口位置组合,以提高自然排烟的效果。     

压缩天然气(CNG)加气站安全监控系统

根据国家科技攻关课题的研究成果以及国家有关法律法规要求,结合加气站安全生产工作的实际需要,辩识与分析CNG加气站的常见危险有害因素;统计与分析近几年加气站事故;采用事故树法对加气站的火灾爆炸危险进行分析;提出事故预防措施;研究并提出CNG加气站安全监控系统的结构和功能设计方案。CNG加气站安全监控系统在对加气站危险有害因素进行辨识、分析和评估基础上,确定需要进行监测的安全相关信息;通过对加气站运行过程中安全状态信息的智能分析,实现事故预警及联锁控制等功能,控制和消除事故风险,预防重大事故的发生;同时系统可以直接纳入应急指挥平台,为应急救援提供详实而准确的现场信息,服务于事故应急救援的科学决策。     

Evidence for bioamplification of nine polychlorinated biphenyl (PCB) congeners in yellow perch (Perca flavascens) eggs during incubation

This study investigated bioamplification of polychlorinated biphenyls (PCBs) in yellow perch (Perca flavescens) eggs resulting from nutrient utilization by developing embryos during incubation. Newly fertilized eggs containing trace levels of PCBs via maternal deposition were collected from an aquaculture pond in which adult broodstock had been reared over their natural lives. The eggs were incubated using a flow through system that received the same pond water at in-situ temperatures from which they were spawned. Replicate samples of eggs were collected at six time points throughout incubation, ranging from day 0 (newly fertilized eggs) to post-hatch larvae (2-d old). Congener specific PCB fugacities in pooled egg samples showed increases over the incubation period. Just prior to hatching, incubated eggs averaged 2.7-fold higher PCB fugacities compared to fresh eggs. The increase in PCB fugacity with egg incubation time was independent of chemical K_OW. After hatching, PCB residues were lost from the larvae, attenuating the maximum chemical fugacity achieved in late-incubated eggs. However, the rate of PCB elimination in the early larvae stages was K_OW dependent such that a significant larvae/egg fugacity ratio was still evident for intermediate and highly hydrophobic compounds 2 d post-hatching. This study provides the first evidence of in-ovo PCB bioamplification in eggs of an aquatic species and suggests that incubating fish embryos are exposed to higher chemical fugacities in-ovo than would be predicted by maternal deposition alone.