武汉市一次污染过程的局地流场和边界层结构的数值模拟

利用2013年11月武汉市逐日空气质量资料、地面气象观测资料、NCEP/NCAR再分析资料和L波段雷达探空资料,通过WRF模式模拟空气污染生消过程中的局地气象条件变化,探讨特殊地形条件下边界层结构变化和局地环流在污染物生消过程中的作用和影响。结果表明：（1）武汉地区当背景环流场强的时候,由地形引起的局地流场对污染物扩散的影响就弱,反之当背景环流场弱的时候, 地形对流场影响明显:夜间为山风,白天为谷风。夜间山风与偏西北气流及偏东气流在武汉及周边地区辐合,形成气流汇聚带,在武汉地区形成一个反复污染带,即由地形引起的局地流场对污染物扩散的贡献就大;（2）武汉地区发生空气污染时,地面湿度较高,边界层呈上干下湿状态,其特征为暖而干且有偏东小风,这导致污染物不断堆积和重污染过程的形成。     

黄河中上游能源化工区大气污染跨界环境影响分析

对黄河中上游能源化工区近地面和边界层顶气象流场及该区域大气污染长距离输送产生的跨界环境影响趋势特征进行了分析。结果表明,该区域近地面和边界层顶的流场总体上为西北向东南流动,大气污染物长距离输送可能影响的区域主要为华中地区;区域冷空气的活动对其大气污染物的清除起重要作用;通过CALPUFF模型的模拟结果表明,该区域SO2的影响程度和范围明显大于NO2,在区域内部存在污染物浓度较高的区域,但未对区外造成显著跨界环境影响。     

Investigation of titanium liquid/gas diffusion layers in proton exchange membrane electrolyzer cells

In a proton exchange membrane electrolyzer cell (PEMEC), liquid/gas diffusion layer (LGDL) is expected to transport electrons, heat, and reactants/products to and from the catalyst layer with minimum voltage, current, thermal, interfacial, and fluidic losses. In addition, carbon materials, which are typically used in PEM fuel cells (PEMFCs), are unsuitable in PEMECs due to the high ohmic potential and highly oxidative environment of the oxygen electrode. In this study, a set of titanium gas diffusion layers with different thicknesses and porosities are designed and examined coupled with the development of a robust titanium bipolar plate. It has been found that the performance of electrolyzer improves along with a decrease in thickness or porosity of the anode LGDL of titanium woven meshes. The ohmic resistance of anode LGDL and contact resistance between anode LGDL and the anode catalyst play dominant roles in electrolyzer performance, and better performance can be obtained by reducing ohmic resistance. Thin titanium LGDLs with straight-through pores and optimal pore morphologies are recommended for the future developments of low-cost LGDLs with minimum ohmic/transport losses.     

Review of advances in the thin layer chromatography of pesticides: 2004–2006

Applications of thin layer chromatography and high performance thin layer chromatography for the separation, detection, and qualitative and quantitative determination of pesticides, other agrochemicals, and related compounds are reviewed for the period from July 1, 2004 to November 1, 2006. Analyses are covered for a variety of samples, such as food, crops, biological, environmental, pharmaceuticals, and formulations, and for residues of pesticides of various types, including insecticides, herbicides, and fungicides, belonging to different chemical classes. In addition to references on residue analysis, studies such as pesticide-structure relationships, metabolism, degradation, and lipophilicity are covered, many of which make use of thin layer radiochromatography.     

川西气田地层水回注选井选层研究

根据川西气田的实际情况,对致密砂岩层回注选井选层技术进行研究,初步建立了致密砂岩层回注选井选层技术,优选出川西气田1、2、3号等5个回注井区。目前,注水规模300m3/d,累计注水量达75 698.8m3,节约生产成本约200万元,且有效缓解了高浓度氯离子地层水外排带来的环保压力。现场回注试验表明:致密砂岩层回注高浓度氯离子地层水是可行的,回注选井选层技术具有现场推广应用价值。     

保护臭氧层谈判中的美欧博弈

臭氧层损耗是重要的全球环境问题之一。最早认识到臭氧层危害的美国率先在国内立法控制相关物质,然而另一大经济体——欧共体,在这一方面却行动迟缓。在保护臭氧层的国际谈判中,美欧之间相互妥协,最终达成了对氟氯烃化合物(CFCs)进行限控的《蒙特利尔议定书》。美欧之间的分歧来自国内化工业巨头的影响,国际经济变动影响外交决策。国际环境问题背后隐藏的经济关系与大国的领导作用是影响国际环境合作的主要因素。     

Influence of dissolved humic substances on the mass transfer of organic compounds across the air-water interface

The effect of dissolved humic substances (DHS) on the rate of water-gas exchange of two volatile organic compounds was studied under various conditions of agitation intensity, solution pH and ionic strength. Mass-transfer coefficients were determined from the rate of depletion of model compounds from an apparatus containing a stirred aqueous solution with continuous purging of the headspace above the solution (dynamic system). Under these conditions, the overall transfer rate is controlled by the mass-transfer resistance on the water side of the water-gas interface. The experimental results show that the presence of DHS hinders the transport of the organic molecules from the water into the gas phase under all investigated conditions. Mass-transfer coefficients were significantly reduced even by low, environmentally relevant concentrations of DHS. The retardation effect increased with increasing DHS concentration. The magnitude of the retardation effect on water-gas exchange was compared for Suwannee River fulvic and humic acids, a commercially available leonardite humic acid and two synthetic surfactants. The observed results are in accordance with the concept of hydrodynamic effects. Surface pressure forces due to surface film formation change the hydrodynamic characteristics of water motion at the water-air interface and thus impede surface renewal.     

层燃螺旋炉排焚烧技术处理含油污泥研究

通过对几种含油污泥无害化处理技术的比选,分析不同处理技术物耗、能耗情况,优选出经济有效的含油污泥焚烧技术,结合新疆油田含油污泥的特点,采用层燃螺旋炉排焚烧技术,利用其燃烧热能生产蒸汽用于原油生产,采用余热吸收急冷与碱液半干法除酸技术,有效控制了二次污染;采用布袋除尘与烟尘固化技术确保了烟气达标排放。年节省成本支出3095.88万元。     

Soil type affects migration pattern of airborne Pb and Cd under a spruce-beech forest of the UN-ECE integrated monitoring site Zöbelboden, Austria

Anthropogenic trace element emissions have declined. However, top soils all over the world remain enriched in trace elements. We investigated Pb and Cd migration in forest soils of a remote monitoring site in the Austrian limestone Alps between 1992 and 2004. Large spatial variability masked temporal changes in the mineral soil of Lithic Leptosols (Skeltic), whereas a significant reduction of Pb concentrations in their forest floors occurred. Reductions of concentrations in the less heterogeneous Cambisols (Chromic) were significant. In contrast, virtually no migration of Pb and Cd were found in Stagnosols due to their impeded drainage. Very low element concentrations (<1 μg l⁻¹) in field-collected soil solutions using tension lysimeters (0.2 μm nylon filters) imply that migration largely occurred by preferential flow as particulate-bound species during intensive rainfall events. Our results indicate that the extent of Pb and Cd migration in soils is largely influenced by soil type.     

水体中常见无机阳离子对TiO2薄膜光催化还原Cr（Ⅵ）的影响

选择了6种水体中常见的阳离子（Na^＋、Mg^2＋、Ca^2＋、Al^3＋、Cu^2＋、Ni^2＋）,分别考查了其对TiO2薄膜光催化还原Cr（Ⅵ）的影响;从光吸收、无机离子本身的性质对光生电子的捕获及传递等讨论了上述离子影响TiO2薄膜光催化还原Cr（Ⅵ）的反应速率的原因。结果表明：由于其不能捕获光生电子,Na^＋、Mg^2＋、Ca^2＋本身对TiO2薄膜光催化还原Cr（Ⅵ）的反应速率影响不大;Al^3＋吸引电子能力较强,成为光生电子和Cr（Ⅵ）之间的桥梁,促进了Cr（Ⅵ）的还原;浓度为1 mmmol/L时,Cu^2＋显著地促进了Cr（Ⅵ）的光催化还原,其主要原因是Cu^2＋捕获光生电子的能力很强,起到了催化剂的作用,而浓度大于10 mmol/L时,Cu^2＋形成单质Cu以及对紫外光的吸收都使促进作用降低;Ni^2＋未充满的d轨道具有获得并传递光生电子的能力,也促进了Cr（Ⅵ）的还原;在浓度同为1mmol/L时,对Cr（Ⅵ）光催化还原的促进作用依次为：Cu^2＋〉Al^3＋〉Ni^2＋〉Na^＋、Ca^2＋、Mg^2＋。