基于生态毒性的再生水补给河流氨氮控制目标研究

再生水补给河流是解决城市景观用水缺乏的重要途径,但是再生水中的氨氮,特别是游离氨对水生生物的毒害作用也不容忽视.针对再生水补给河流的典型场景,根据物种敏感度分布法(Species Sensitivity Distribution,SSD),计算得到游离氨的属急性毒性基准最大质量浓度(Criterion Maximum Concentration,CMC)为0.093 mg/L.以保护95％水生生物为目标的河水氨氮控制目标分别为4.37 mg/L(水温T≤12℃)和1.73 mg/L(水温T＞ 12℃).根据再生水补给河流的不同比例(体积比),计算再生水的氨氮控制目标.当河流上游来水分别满足地表水环境质量标准Ⅳ、Ⅴ类水体要求和CMC值,再生水占混合后河水的比例为20％～100％且水温T＞ 12℃时,再生水氨氮控制目标分别为1.7～2.6 mg/L、0.6～1.7 mg/L和1.7 mg/L;当河流上游来水分别满足Ⅳ、Ⅴ类水体要求,再生水占混合后河水的比例为50％～100％且水温T≤12℃时,再生水氨氮控制目标分别为4.4～7.2 mg/L和4.4～6.7 mg/L.当河水全部由再生水组成时,推荐再生水的氨氮控制目标为1.7 mg/L(水温T＞12℃)和4.4mg/L(水温T≤12℃).     

顶空被动加标系统的多介质动力学模型

使用多介质模型建模方法,构建了针对疏水性液体物质的顶空被动加标系统的动力学模型,以浮萍生长抑制试验系统和鱼类胚胎毒性试验系统为例,得出了3种不同性质的疏水性液体物质正壬烷、十甲基环五硅氧烷（D5）和邻苯二甲酸（2-乙基己基）酯（DEHP）在顶空被动加标系统中的浓度变化,并使用实测浓度对模型进行验证.结果表明,正壬烷和D5在两类系统中平衡24h后,水中浓度便已达到完全平衡时浓度的80%以上,而DEHP的平衡时间很长,不适合使用顶空被动加标系统开展试验,原因是DEHP的挥发性极低.实测浓度和模型预测结果偏差较小.敏感性分析表明,试验系统参数中容器直径对待测物质在水中浓度影响较大,因此可通过调整容器直径来缩短平衡时间,或提高平衡后化学物质在水中的浓度.使用所构建的模型可确定试验系统平衡时间、水中待测物质浓度和待测物质添加体积是否满足试验需求,并可通过敏感性分析来优化试验系统参数,提升试验效率和质量.以上结果完善了顶空被动加标系统应用的理论基础.     

Relationship between electric spark sensitivity and activation energy of the thermal decomposition of nitramines for safety measures in industrial processes

This study presents a new simple correlation between electric spark sensitivity of nitramines and their activation energies of thermolysis, which are important for safety measures in industrial processes. The new correlation can help to elucidate the mechanism of initiation of energetic materials by electric spark. It can be used to predict the magnitude of electric spark sensitivity of new nitramines, which is difficult to measure. The methodology assumes that electric spark sensitivity of a nitramine with general formula C_aH_bN_cO_d can be expressed as a function of its activation energy of thermal decomposition as well as optimized elemental composition and the contribution of specific molecular structural parameters. The new correlation has the root mean square and the average deviations of 1.37 and 1.09 J, respectively, for 21 nitramines with different molecular structures. The proposed new method is also tested for 16 nitramines so that there is no experimental data of electrostatic sensitivity for them.     

PACIFIC NORTHWEST REGIONAL ASSESSMENT: THE IMPACTS OF CLIMATE VARIABILITY AND CLIMATE CHANGE ON THE WATER RESOURCES OF THE COLUMBIA RIVER BASIN1

ABSTRACT: The Pacific Northwest (PNW) regional assessment is an integrated examination of the consequences of natural climate variability and projected future climate change for the natural and human systems of the region. The assessment currently focuses on four sectors: hydrology/water resources, forests and forestry, aquatic ecosystems, and coastal activities. The assessment begins by identifying and elucidating the natural patterns of climate vanability in the PNW on interannual to decadal timescales. The pathways through which these climate variations are manifested and the resultant impacts on the natural and human systems of the region are investigated. Knowledge of these pathways allows an analysis of the potential impacts of future climate change, as defined by IPCC climate change scenarios. In this paper, we examine the sensitivity, adaptability and vulnerability of hydrology and water resources to climate variability and change. We focus on the Columbia River Basin, which covers approximately 75 percent of the PNW and is the basis for the dominant water resources system of the PNW. The water resources system of the Columbia River is sensitive to climate variability, especially with respect to drought. Management inertia and the lack of a centralized authority coordinating all uses of the resource impede adaptability to drought and optimization of water distribution. Climate change projections suggest exacerbated conditions of conflict between users as a result of low summertime streamfiow conditions. An understanding of the patterns and consequences of regional climate variability is crucial to developing an adequate response to future changes in climate.     

生态敏感度评价指标体系在规划中的应用研究

生态敏感度是评价区域生态脆弱性程度的指标.在隆昌城市战略规划中,开展了生态敏感度评价工作.通过对生态敏感因子的提取、基于AHP法对因子生态敏感等级的划定、对不同开发用地类型对敏感因子受感性的分析,构建了服务于规划应用的二维生态敏感度评价体系.该体系既体现不同因子下的生态敏感度,又体现了不同开发类型下生态敏感因子的重要性,在战略规划中直接辅助城市规划中开发区域的划定与开发类型的选择.     

我国淡水中铜的水质基准及生态风险评估研究

铜是生命体必需的微量元素,但是摄入量过高又会对机体产生危害。以我国淡水生态系统为保护对象,选取有代表性的本地物种及敏感性高的模式生物作为受试生物进行急慢性毒理试验,同时,筛选收集其他淡水生物的毒性数据,通过物种敏感度分布法进行铜的水质基准阈值的推导。最后,运用商值法对我国淡水环境中铜的生态风险进行评估。结果表明,铜的短期危险浓度和长期危险浓度分别为30.9,4.1μg/L。铜对我国淡水水体的风险相对较低,在低剂量长期暴露的情况下,部分水体会对水生生物产生潜在的生态风险。     

Dynamic modeling and bifurcation analysis for the methyl isocyanate hydrolysis reaction

The aim of this work was to characterize the methyl isocyanate hydrolysis reaction and to identify its operational criteria. The parametric sensitivity and dynamic stability methodologies were performed at the Bhopal disaster circumstances, over the relevant operating parameter space. Stable and unstable conditions, bifurcations points, turning points and oscillatory behavior were determined. The combined methodology give useful guidance on the operative conditions selection and the appropriate strategy to overcome hazardous situations. The obtained results demonstrated high sensitivity to small perturbations (thermal runaway) and prevalent oscillatory behavior. Moreover, the following critical parameters for the studied dynamic system were defined: the inverse residence time of 1.5700103 and the heat transfer coefficient of 752.394.     

基于物种敏感性分布法的生态风险评价研究进展

生态风险评价是认识生态健康和污染物可能对生态环境产生不良影响的重要手段,而物种敏感性分布法是使用较为广泛的评价方法,其核心步骤是筛选出合适物种的毒性数据进行曲线拟合。在简要介绍物种敏感性分布法原理和步骤的基础上,综述了物种敏感性分布法应用的几个关键问题,即物种筛选、毒性数据选择和拟合模型确定。针对特殊水体,提出了基于区域同类型水环境物种对比的物种筛选法和基于水环境历史物种比较的物种筛选法。最后对未来的研究工作进行了展望,指出现有研究的不足和未来研究的方向。     

燃煤电厂氮氧化物产生浓度影响因素的敏感性和相关性研究

燃煤电厂氮氧化物产生浓度监测是计算排放浓度的基础,要实现氮氧化物排放浓度的控制,研究其产生浓度的影响因素很重要.因此,本文选取了187组燃煤电厂的现场实测及历史实测氮氧化物数据,装机规模覆盖12～1000MW,通过敏感性分析和偏相关分析,对不同类型燃煤机组氮氧化物产生浓度的各主要影响因素进行定量分析.敏感性分析发现,采用低氮燃烧技术的发电锅炉中,影响氮氧化物产生浓度的因素依次为机组规模、空气过剩系数、机组负荷率、煤中挥发分、煤中含氮量;未采用低氮燃烧技术的发电锅炉中,影响氮氧化物产生浓度的因素依次为煤中挥发分、空气过剩系数、机组规模、机组负荷率、煤中含氮量.通过偏相关分析发现,对于采用低氮燃烧技术的发电锅炉,在置信水平为99%的情况下,氮氧化物产生浓度与机组规模呈负相关关系,偏相关系数为-0.412;与空气过剩系数呈正相关关系,偏相关系数为0.265;与煤中挥发分呈负相关关系,偏相关系数为-0.355;与机组负荷率呈正相关关系,偏相关系数为0.245;与煤中含氮量的相关性不显著.对于未采用低氮燃烧技术的发电锅炉,在置信水平为99%的情况下,氮氧化物产生浓度与机组规模呈正相关关系,偏相关系数为0.345;与空气过剩系数呈正相关关系,偏相关系数为0.325;与煤中挥发分呈负相关关系,偏相关系数为-0.543;与机组负荷率及煤中含氮量的相关性不显著.     

基于变维分形理论的滑坡空间分布特征研究

为了对滑坡的空间分布特征进行定量的研究,以香溪河流域高阳—官庄坪段为例,基于变维分形理论对滑坡空间分布的分形模型进行了优化,定量地得到了各影响因子与滑坡空间分布之间的敏感性关系,同时对滑坡空间分布的成因进行了定性分析,结果与利用分形理论得到的定量敏感性关系相一致,表明优化的分形模型具有可靠性。