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111.
台风作为全球发生频率最高,影响最严重的一种自然灾害,对我国的影响也非常严重。在巨灾风险证券化、巨灾债券已成为巨灾保险业大趋势的背景下,发展我国台风灾害债券具有重要的现实意义。以我国受台风灾害影响最严重的省份——广东省为研究对象,收集了其近30年相关台风损失数据,利用非寿险精算技术分析其台风的损失分布和次数分布,在此基础上利用CAMP模型和现金流分析对广东省的台风灾害债券做了初步设计。 相似文献
112.
结合高空、地面实况观测数据以及1°×1°NCEP客观再分析资料,对2009年6月28日20时至29日20时(北京时)发生在三峡上游地区的一次区域暴雨过程进行了中尺度特征诊断,结果表明本次过程是东北低涡和副高稳定少动的大尺度环流背景形势下,由于高原低值系统在东移过程中与西南涡结合而产生的强降水天气过程。高原上不稳定能量的扰动和下传为西南涡的产生提供了必要能量条件,高低层的水汽平流和水汽辐合的交汇地带与最强降水带存在较好的一致性。另外,利用WRF中尺度数值模式对该次过程进行了数值模拟,结果显示在同化了地面和高空常规观测资料后,模式模拟效果得到明显改善,模拟降水能够大致体现该次过程的总的降水演变和分布情况,但后期模拟降水偏大。数值诊断结果发现,盆地西部与上升气流相伴的正涡度柱的演变过程与强降水的发生过程密切相关,该因子对于正确预报降水发生时间具有指示意义。 相似文献
113.
Dechlorane Plus (DP) has been determined in surface sediments from three Chinese coastal bays, e.g. Jiaozhou, Sishili and Taozi Bay in North China. DP concentrations ranged from <1.2 to 187 pg g−1 dry weight (dw) (mean: 24.7 pg g−1 dw) in Jiaozhou Bay, <1.2 to 135 pg g−1 dw (mean 69.9 pg g−1 dw) in Sishili Bay and <1.2 to 66.7 pg g−1 dw (mean: 40.4 pg g−1 dw) in Taozi Bay, respectively. Additionally, two dechlorinated species were quantified, which accounted for 0.6-5.1% of the ∑DP concentration.The fsyn values (syn-isomer/(syn- + anti-isomer)) in sediments from Jiaozhou Bay (mean 0.29) were close to the technical DP mixture (0.2-0.4), probably indicating local inputs of DP. In contrast, sediments in Sishili and Taozi Bay showed much lower fsyn values (mean 0.16). During transportation the DP isomers are subject to stereo selective degradation which partly resulted in the relative enrichment of anti-DP in coastal sediments. 相似文献
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116.
提出了水质凯氏氮标准样品的研究方法。在研究过程中,完成了样品的配制、均匀性、稳定性等工作。经过多家实验室协作定值,确定了样品的标准值及不确定度,并提供使用。 相似文献
117.
Huan Zhong 《Environmental pollution (Barking, Essex : 1987)》2009,157(3):981-986
This study compared the relative importance of three types of sorption (organic matter-particle, mercury-organic matter and mercury-particle) in controlling the overall mercury partitioning and bioavailability in sediments. We found that all three types of sorption were important for both inorganic mercury (Hg) and methylated mercury (MeHg). Mercury-particle sorption was more important than mercury-fulvic acid (FA) sorption in increasing the mercury concentrations with increasing aging. Bioavailability (quantified by gut juice extraction from sipunculans) was mainly controlled by mercury-particle sorption, while FA-particle and mercury-FA sorption were not as important, especially for MeHg. Bacterial activity also increased the partitioning of Hg or MeHg in the sediments and was further facilitated by the presence of organic matter. The bioavailability of Hg or MeHg from sediments was only slightly influenced by bacterial activity. This study highlights the importance of sorption from various sources (especially mercury-particle sorption) as well as bacteria in controlling the partitioning and bioavailability of Hg or MeHg in sediments. 相似文献
118.
Ionic composition of TSP and PM2.5 during dust storms and air pollution episodes at Xi'an,China 总被引:1,自引:0,他引:1
Zhenxing Shen Junji Cao Richard Arimoto Zhiwei Han Renjian Zhang Yuemei Han Suixin Liu Tomoaki Okuda Shunsuke Nakao Shigeru Tanaka 《Atmospheric environment (Oxford, England : 1994)》2009,43(18):2911-2918
TSP and PM2.5 samples were collected at Xi'an, China during dust storms (DSs) and several types of pollution events, including haze, biomass burning, and firework displays. Aerosol mass concentrations were up to 2 times higher during the particulate matter (PM) events than on normal days (NDs), and all types of PM led to decreased visibility. Water-soluble ions (Na+, NH4+, K+, Mg2+, Ca2+, F?, Cl?, NO3?, and SO42?). were major aerosol components during the pollution episodes, but their concentrations were lower during DSs. NH4+, K+, F?, Cl?, NO3?, and SO42? were more abundant in PM2.5 than TSP but the opposite was true for Mg2+ and Ca2+. PM collected on hazy days was enriched with secondary species (NH4+, NO3?, and SO42) while PM from straw combustion showed high K+ and Cl?. Firework displays caused increases in K+ and also enrichments of NO3? relative to SO42?. During DSs, the concentrations of secondary aerosol components were low, but Ca2+ was abundant. Ion balance calculations indicate that PM from haze and straw combustion was acidic while the DSs samples were alkaline and the fireworks' PM was close to neutral. Ion ratios (SO42?/K+, NO3?/SO42?, and Cl?/K+) proved effective as indicators for different pollution episodes. 相似文献
119.
反渗透处理稀土氨氮废水试验研究 总被引:4,自引:2,他引:2
根据稀土冶炼厂排放的碳铵沉淀洗涤废水的水质情况,采用NH4Cl和 NaCl模拟废水进行了反渗透可行性对比实验。模拟实验发现,在相同条件下反渗透对NaCl 较NH4Cl 有着更高的去除率,而NH4Cl 相对NaCl则有着更高的产水速率。实际废水试验结果表明,在恒定操作压力范围内回收率为65%的条件下,NH4Cl浓度为2.85 g/L的碳铵沉淀洗涤废水经反渗透处理其NH4Cl去除率为77.3%,可作为氨氮废水的预处理。对该废水处理成本进行了分析,得出其约为2.7元/m3,比相近浓度氨氮废水的氨吹脱处理成本节省约26%。 相似文献
120.
含中间层的DSA电极电催化氧化硝基苯废水的研究 总被引:1,自引:0,他引:1
为了提高难降解有机废水的可生化性,以及更高效地去除废水中的特征污染物,同时避免二次污染,利用自制的含锡锑中间层的钌钯氧化物涂层电极对有机废水中的硝基苯进行处理,并利用SEM、XRD等方法对电极中间层、表层进行微观表征。微观测试表明,基体、中间层、表层之间结合力较强,有利于增强电极寿命;水处理实验表明,电催化氧化反应体系适合高浓度有机废水的处理,由于该反应体系需要外加电解质加强传质,这在实际运用中为废水中盐度的处理提供了一种新的途径,当电流密度为20 mA/cm2、电解质浓度为10 g/L、pH=5、极板间距=2 cm时,电催化氧化体系对硝基苯具有较高的去除效率。 相似文献