A 21-year record of methoxylated and hydroxylated polybrominated diphenyl ethers in sediments from the East China Sea

Sediments are major sinks for organic pollutants and therefore can be used as archives of pollutant history. Methoxylated (MeO-) and hydroxylated (OH-) polybrominated diphenyl ethers (PBDE) are of increasing concern because of their potential toxicity and worldwide distribution. However, there is limited information on these compounds in marine environments. Here we determined the contents of nine MeO-PBDE, ten OH-PBDE and total organic carbon in a sediment core collected from the inner shelf of the East China Sea in 2009. The historical trends of 6-MeO-BDE47, 6-OH-BDE47 and total organic carbon were reconstructed. Our results show that 6-MeO-BDE47 concentrations present no significant trend from 1987 to 2005 and then increase from 2005 to 2008. 6-OH-BDE47 concentrations generally increase slightly from 1987 to the end of the 1990s and then decrease. Comparisons between 6-OH-BDE47 and 6-MeO-BDE47 as well as total organic carbon suggest that 6-OH-BDE47 is mainly from terrigenous inputs.     

高校宿舍建筑火灾场景人员疏散模拟研究

采用Building Exodus 4.0模拟软件,研究了某校园宿舍建筑火灾场景下的出口宽度,可用出口数目,可用疏散楼梯数目以及人员对出口的熟悉程度等对疏散的影响规律.结果表明,在出口宽度到达某一阈值前,所需疏散时间随其增加而减少,超过该阈值之后,继续增加宽度对所需疏散时间影响甚微;随着可用出口和疏散楼梯数目的增加,所需疏散时间逐渐减少;人员对出口越熟悉,所需疏散时间越短.     

Governance approach to China''s environmental challenges:Towards a theoretical synthesis

This paper reviewed recent research in environmental governance as a response to environmental challenges at various spatial, temporal and administrative scales. It documented the shift of approach from regulation to governance, and attempted to provide a comprehensive understanding why and how the transformation occurred. It also described major factors and forces of environmental governance, and discussed research advance in environmental governance theory. Finally, this paper summarized recent research findings on environmental governance in China, and listed policy recommendation for enhancing the governance.     

Speciation and quantification of vapor phases in soy biodiesel and waste cooking oil biodiesel

This study characterizes the compositions of two biodiesel vapors, soy biodiesel and waste cooking oil biodiesel, to provide a comprehensive understanding of biodiesels. Vapor phases were sampled by purging oil vapors through thermal desorption tubes which were then analyzed by the thermal desorption/GC/MS system. The results show that the compounds of biodiesel vapors can be divided into four groups. They include methyl esters (the main biodiesel components), oxygenated chemicals, alkanes and alkenes, and aromatics. The first two chemical groups are only found in biodiesel vapors, not in the diesel vapor emissions. The percentages of mean concentrations for methyl esters, oxygenated chemicals, alkanes and alkenes, and aromatics are 66.1%, 22.8%, 4.8% and 6.4%, respectively for soy biodiesel, and 35.8%, 35.9%, 27.9% and 0.3%, respectively for waste cooking oil biodiesel at a temperature of 25 ± 2 °C. These results show that biodiesels have fewer chemicals and lower concentrations in vapor phase than petroleum diesel, and the total emission rates are between one-sixteenth and one-sixth of that of diesel emission, corresponding to fuel evaporative emissions of loading losses of between 106 μg l⁻¹ and 283 μg l⁻¹. Although diesels generate more vapor phase emissions, biodiesels still generate considerable amount of vapor emissions, particularly the emissions from methyl esters and oxygenated chemicals. These two chemical groups are more reactive than alkanes and aromatics. Therefore, speciation and quantification of biodiesel vapor phases are important.     

基于EFDC的二滩水库水温模拟及水温分层影响研究

采用EFDC模型模拟二滩水库2006年3～7月的水温变化过程。通过分析与热交换和热传递相关的模型参数,发现太阳短波辐射中快速波所占的比例和太阳短波辐射在水体中的慢速衰减系数这两个参数值的增大均会引起表层水温升高、底层水温降低,而太阳短波辐射在水体中的快速衰减系数对水温的影响并不明显。将不同时期坝前水温和不同断面水温的模拟值和观测值进行比较,以率定模型参数。结果显示EFDC模型能较好地模拟出大型深水库不同时期水温分层结构及沿程发展变化过程。在此基础上,分析该水库的水温分层规律,并结合水库取水规则对比分析建库前后下游河道水温的差别,以期为水库取水设计和运行管理提供科学参考,以此来减缓水库水温分层带来的影响,保护下游河道生态环境和水生生物的多样性     

质量、职业健康安全及环境三体系整合

就济钢实施质量、职业健康安全及环境三体系整合工作的依据、可行性进行论证,介绍了三体系整合的情况及实施放果。     

基于风险的检测技术在炼油设备分析中的应用

运用RBI技术在加氢装置冷高压分离器和冷低压分离器及相连管线进行的RBI分析过程,并根据风险分析的结果制定了检验计划。通过这次分析,可以看到RBI分析是一个有充分数据支持的系统的程序化的分析过程,其结论反映了设备在实际操作中的真实状况,可以为制定检修计划和长期的检修策略提供较为可靠的依据。     

Diversity and community composition of phosphorus accumulating organisms (PAOs) in the sediments of the Sanshiliujiao Lake reservoir北大核心CSCD

The diversity and community composition of phosphorus accumulating organisms (PAOs) in the sediments of the Sanshiliujiao Lake reservoir in Pingtan island, Fujian Province, were investigated by terminal restriction fragment length polymorphism (T-RFLP) methods combined with the construction of clone libraries. The diversity of PAOs in summer samples was significantly higher than that in winter. The dominant terminal restriction fragments (T-RFs) of PAOs were in the range of 200 to 300 bp in summer, while they were in the range of 150 to 200 bp in winter. Cloning sequencing and phylogenetic analysis showed that the main phyla of PAOs in the sediment of the Sanshiliujiao Lake reservoir were Proteobacteria, Actinobacteria, and Acidobacteria. Anaeromyxobacter, Azospirillum, Microlunatus phosphovorus, and Burkholderia were the dominant genera in the summer samples. Anaeromyxobacter, Methylobacterium, Solibacter, Azospirillum, and Microlunatus phosphovorus were the dominant genera in sediment samples in winter. The results of this study demonstrated that the diversity and community composition of PAOs in the sediments of the Sanshiliujiao Lake reservoir had specific seasonal characteristics. Various forms of phosphorus also showed their influence on the diversity of PAOs, especially Fe/Al-P. Our findings lays a scientific foundation for the future disclosure of microbial mechanisms involved in the phosphorus metabolic cycle in the sediments of reservoirs. © 2018 Science Press. All rights reserved.     

Genetic diversity and genetic differentiation of Squaliobarbus curriculus from the Pearl River based on mitochondrial D-loop sequences北大核心CSCD

Squaliobarbus curriculus is one of the most economically important edible freshwater fish in the Pearl River. To assess the level of genetic diversity and genetic variation of S. curriculus populations w ithin t he Pearl R iver, samples were collected from six geographical populations from six drainages. 978 base pairs of the D-loop sequence were obtained as a molecular marker. 106 haplotypes were defined among 170 S. curriculus individuals. Populations of S. curriculus in the Pearl River displayed a high haplotypic diversity index (h = 0.9820) and high nucleotide diversity index (π = 0.01353). T he results of genetic distance and genetic differentiation index show that genetic differentiation among S. curriculus populations is not significant. The neighbor-joining tree shows two clades. Clade A is composed of most haplotypes of S. curriculus. Clade B includes two private haplotypes from the Xijiang River. Haplotype network analysis is consistent with the results of genetic distance and genetic differentiation. The results of AMOVA analysis showed that most variation was found within populations (99.36%). Neutral test analysis explained that there was population expansion in the history of S. curriculus in the Pearl River. Xijiang River could be the center of origin, as supported by all the results. © 2018 Science Press. All rights reserved.     

考虑可靠性要素的应急物流设施选址分配问题的建模研究

为了提升防灾减灾系统的运行效率,研究应急物流设施选址-分配问题,构建考虑设施可靠性要素的双目标混合整数规划模型,以最小化系统总成本和最大化客户需求覆盖率为目标,确定应急物流中心的选址区位和各节点间各种物资的分配方案;考虑即使是选中开放的设施,也存在一定的中断概率,因此以不同情形表示开放设施中存在中断设施的情况;最后,通过MATLAB实现NSGAII算法,对模型求解,得出灾害发生时应急物流设施需求覆盖率与系统总成本的关系,为灾害发生后救援系统救灾成本和受灾点需求满足程度的权衡优化,提供可参考思路。