61 research outputs found

    Pollution Characteristics and Ecological Risk of PBDEs in Water and Sediment from an Electronic Waste Dismantling Area in Taizhou

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    以台州某电子垃圾拆解工业园为圆心,在半径为16 km的范围内,由近及远设计了C(3 km)、S(5~10 km)和R(10~16km)三圈共30个采样点,研究了该区域水及沉积物中多溴联苯醚(PBDEs)的污染特征与生态风险.结果表明,水中PBDEs含量为9.4~57.2 ng·L~(-1),平均值为25.9 ng·L~(-1);沉积物中PBDEs含量为3.7~38 775 ng·g~(-1),平均值为2 779 ng·g~(-1);BDE-209均为主要成分.水及沉积物中PBDEs含量的空间分布态势均为:C圈>S圈>R圈,沉积物中PBDEs含量和离工业园区中心的距离呈极显著负相关(P S > R. Furthermore,the concentrations of PBDEs in sediments showed significant negative correlation against the distance from the industrial park( P < 0. 01). Compared with other regions around the world,the PBDEs contamination was more serious in the area,which indicated that e-waste dismantling activity was one of the significant sources for PBDEs pollution. It was estimated that a total of 30. 7 t PBDEs( including 28. 9 t BDE-209) was discharged into surrounding environment as a result of dismantling industrial activities in last 40 years. A preliminary ecological risk assessment for PBDEs in water and sediments was conducted by hazard quotient method. The results demonstrated that the Penta-BDEs in the center of e-waste dismantling area( a radius of 1. 5 km) was at particularly high risk level and could cause serious influence on the ecological safety and human health.环境保护公益性行业科研专项(201309047

    Size Distribution of Particle and Polycyclic Aromatic Hydrocarbons in Particle Emissions from Simulated Emission Sources

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    采用再悬浮箱模拟得到不同粒径的烹调油烟、生物质和塑料燃烧烟尘、汽车尾气和发电机烟气等颗粒,并用gC/MS对不同粒径颗粒中18种多环芳烃(PAHS)进行了分析.结果表明,烹调油烟中颗粒物存在0.44~1.0μM和2.5~10μM两个峰值,稻草和木材燃烧排放烟尘只有0.44~1.0μM一个峰值,塑料燃烧排放烟尘的峰值不明显,汽车尾气尘因含有大量的水汽导致其粒径峰值出现在2.5~10μM,而发电机排放的烟尘约93%集中在≤2.5μM的粒径范围.烹调油烟和汽车尾气尘中低环数PAHS在2.5~10μM范围内的峰值明显;随环数增加,0.44~1.0μM范围内的峰值变得明显;不同排放源亚微米颗粒中单一PAH占全部颗粒态中该PAH的比例都呈现随分子量的增大而增大的趋势.烹调油烟和燃烧排放颗粒中PAHS的组成以菲占主导,但汽车尾气和发电机烟尘中含量最高的PAHS分别是萘和苯并[g,H,I]苝.来源特征比值的比较显示,烹调油烟与生物质燃烧颗粒中PAHS的源特征较为接近,但两者都不同于汽车尾气和发电机烟尘.Particles from cooking lampblack,biomass and plastics burning smoke,gasoline vehicular exhausts and gasoline generator exhausts were prepared in a resuspension test chamber and collected using a cascade MOUDI impactor.A total of 18 polycyclic aromatic hydrocarbons( PAHs) associated with particles were analyzed by GC-MS.The results showed that there were two peaks in the range of 0.44-1.0 μm and 2.5-10 μm for cooking lampblack,and only one peak in the range of 0.44-1.0 μm for straw and wood burning smoke.But there were no clear peak for plastics burning smoke.The peak for gasoline vehicular exhausts was found in the range of 2.5-10 μm due to the influence of water vapor associated with particles,while the particles from gasoline generator exhausts were mainly in the range of ≤2.5 μm( accounting for 93% of the total mass).The peak in 2.5-10 μm was clear for cooking lampblack and gasoline vehicular exhausts.The peak in the range of 0.44-1.0 μm became more and more apparent with the increase of PAHs molecular weight.The fraction of PAH on particles less than 1.0 μm to that on the total particles increased along with PAH's molecular weight.Phenanthrene was the dominant compound for cooking lampblack and combustion smoke,while gasoline vehicular exhausts and generator exhausts were characterized with significantly high levels of naphthalene and benzo[g,h,i]perylene, respectively.The distribution of source characteristic ratios indicated that PAHs from cooking lampblack and biomass burning were close and they were different from those of vehicular exhausts and generator exhausts.国家自然科学基金项目(40971257;41171365); 环境保护公益性行业科研专项(201009004

    The Design、Calculation and Adjustment of Multi-Differential Vacuum System

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    兰州重离子加速器(HIRFL)后束运线TR2实验终端,是一个用于开展超重核研究的实验终端,实验系统工作时要求充入氦气,压强为100Pa左右,而后束运线上真空度要求为10E-6Pa,所以如何实现从实验终端充气压强为100Pa到后束运线上压强为10E-6Pa真空度的顺利过渡便成了一个重要课题。 本文从差分真空系统的原理着手,通过对差分系统材料、测量元件以及排气系统的选择,排气性能测试等,设计了TR2实验终端差分真空系统——四级差分真空系统。通过安装测试,将理论计算值与静态测试结果做了比较,引出了差分系统中充气气流效应的概念,并对该系统中充气气流效应进行定量和定性的分析,改进了差分真空系统的设计。 本文用真空系统中气体的流动与电子学电路中电子的流动相等效的思路,把四级差分真空系统等效成电子学电路,并用PSpice软件仿真计算四级差分真空系统中各级差分真空室的压力分布,并与实验结果作比较。 理论计算和静态测试结果均表明,TR2实验终端利用四级差分真空系统,可以实现从100Pa到后束运线上10E-6Pa真空度的顺利过渡兰州重离子加速器(HIRFL)后束运线TR2实验终端,是一个用于开展超重核研究的实验终端,实验系统工作时要求充入氦气,压强为100Pa左右,而后束运线上真空度要求为10E-6Pa,所以如何实现从实验终端充气压强为100Pa到后束运线上压强为10E-6Pa真空度的顺利过渡便成了一个重要课题。 本文从差分真空系统的原理着手,通过对差分系统材料、测量元件以及排气系统的选择,排气性能测试等,设计了TR2实验终端差分真空系统——四级差分真空系统。通过安装测试,将理论计算值与静态测试结果做了比较,引出了差分系统中充气气流效应的概念,并对该系统中充气气流效应进行定量和定性的分析,改进了差分真空系统的设计。 本文用真空系统中气体的流动与电子学电路中电子的流动相等效的思路,把四级差分真空系统等效成电子学电路,并用PSpice软件仿真计算四级差分真空系统中各级差分真空室的压力分布,并与实验结果作比较。 理论计算和静态测试结果均表明,TR2实验终端利用四级差分真空系统,可以实现从100Pa到后束运线上10E-6Pa真空度的顺利过

    黄土丘陵区小流域土壤稳定入渗速率空间变异

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    影响土壤降水入渗的主要因素是土壤自身的性质如土壤质地、容重、含水率、地表结皮、水稳性团粒含量、利用方式等。土壤质地不同[1],土地利用方式不同[1,2 ],土壤入渗速率均存在较大差异。周国逸等人的研究认为 ,地表结皮的形成能很快降低土壤入渗速率 ,使裸地土壤入渗速率减小到未形成结皮前的 4.84% [3];蒋定生等研究黄土高原土壤入渗速率时发现 ,土壤瞬时入渗速率与土壤容重、含水量、水稳性团粒含量间存在显著相关性[4 ]。由于受野外降雨入渗试验装置的限制 ,上述研究均停留在双环法试验或室内外人工模拟降雨定点小区实 (试 )验水平上 ,而有关整个流域土壤入渗空间变异性问题却研究较少。蒋定生等[4 ]利用双环法将黄土高原土壤入渗速率进行了系统分区 ,而该项研究着重于宏观 ,并且利用双环法测得的数值比实际情况要大得多[1,4 ]。本文利用小型野外模拟降雨试验装置[5 ],以陕北安塞县纸坊沟小流域为例 ,研究不同土地利用方式、地形地貌条件下该流域土壤入渗速率水平和垂直变化规律 ,以期从微观角度探讨小流域在不同土地利用及地形地貌条件下各点土壤入渗速率的空间变异规律。1 试验区概况及试验方法纸坊沟小流域地处黄土高原腹地 ..

    超高真空系统内Mn-Zn铁氧体材料的表面保护及清洁方法研究

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    分别对测试系统本底及经两种方法处理的M n-Zn铁氧体样品进行了测试,分析其主要的出气成分,计算出处理后的样品材料出气率。通过测试与分析,得出了对置于超高真空环境内的M n-Zn铁氧体材料表面的保护和清洁方法

    Research Report on the Synthesis of Bio-gasoline and Butanol by Highly Efficient Hydrolysis of Biomass

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    This report mainly covers the researches on the efficient hydrolysis technologies of biomass by hot water and ultra low acid combining with enzymes, acetone --butanol fermentation, and liquid alkanes production via aqueous phase reforming. Meanwhile, th

    VAKTRAK在CSR真空系统设计中的应用

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    为了准确而快速地设计计算细长形如储存环和束运线的真空系统,使之满足束流存储对真空系统内总压、分压分布的要求,有人建立了传输矩阵的模型来表述分子流条件下的气体分子传输机理,并和计算机技术结合,形成了一种简洁、高效的真空系统设计的新方法——VAKTRAK。通过介绍VAKTRAK在CSR真空系统设计中的运用,给出了此程序的使用方法和计算结果

    CHAR AS CATALYST FOR HYDROGEN PRODUCTION BY GLYCEROL REFORMING

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    Using char as catalyst, fixed bed reactor. The results show decrease with increasing of WHSV, hydrogen production from the steam reforming reaction of glycerol was studied in a that the hydrogen yield, the potential hydrogen yield and carbon conversion

    清洁、大流量真空差分系统的研制

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    本研究是为了设计一套大流量、清洁的真空差分系统.计算了超重反冲核实验装置终端真空差分系统各级的真空度;介绍了差分系统的设计和真空泵、测量设备选择;选择能在高压强下连续运行的新型分子/增压泵作为过渡流范围内的主排气泵,对分子增压泵进行了性能测试并对差分系统进行了模拟靶室实验,最后对实验结果进行了分析

    木炭催化甘油重整制氢研究

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    Using char as catalyst, fixed bed reactor. The results show decrease with increasing of WHSV, hydrogen production from the steam reforming reaction of glycerol was studied in a that the hydrogen yield, the potential hydrogen yield and carbon conversion
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