NOX总量指标混合加权分配方法的研究

随着我国环境保护工作的深入发展,单因子加权已经越来越不能满足环境管理、环境预测与规划、环境影响评价的要求。＂十二五＂是我国重点区域实施火电氮氧化物总量控制的重要时期,本文提出了一种适合我国火电氮氧化物总量控制的多因子混合加权分配模型,使总量指标分配更具有公平性和可行性。     

时段长取值变化下的径流年内分配特征研究

利用东江流域控制站博罗站1954—2009年日平均流量资料,选取集中度、集中期、不均匀系数和极值比4项指标,研究了河川径流年内分配特征,在不同时段长取值下的变化规律及年际变化特征。结果表明：东江径流年内分配的集中程度及时间,基本上不会受到时段长取值大小变化的影响。集中度多年均值为0.35,集中期多年均值出现在7月上旬。径流年内分配不均匀性和变化幅度,随时段长取值缩短而增大,并与时段长的对数线性负相关。不均匀系数多年均值由基于月平均流量分配的0.62上升到基于1 d平均流量分配的0.89,极值比多年均值由基于月平均流量分配的8.63上升到基于1 d平均流量分配的39.55。径流年内分配特征在不同时段长取值下的逐年变化规律基本相似,但由于流域水资源开发等人类活动的显著影响,1973年之后的集中度、不均匀系数和极值比均明显减小,且径流年内分配的集中程度和不均匀性均要小于珠江流域的另外两大水系西江和北江。     

圆钢管轻集料混凝土梁与混凝土桥墩连接节点试验研究

为了解决圆钢管轻集料混凝土梁与混凝土桥墩的整体连接问题,共设计了穿心钢筋、穿心钢筋加弯矩传递板和穿心工字钢3种节点连接形式,采用拟静力试验研究了刚节点在低周反复荷载作用下的抗震耗能性能。试验结果表明,3种节点都具有良好的抗震耗能性能,等效粘滞阻尼系数都超过了钢筋混凝土结构要求的0.1,延性系数都大于规范规定的2;在节点屈服以后,3种节点仍然具有一定的承载力,其中穿心钢筋和穿心工字钢节点的延性系数和等效粘滞阻尼系数基本相同,穿心钢筋加弯矩传递板较其他2种刚节点稍差。     

岷江下游小型集水区3种人工林对降雨重金属含量的影响

为了解人工林对大气污染物质的过滤作用,分析研究了2011年11月10日到2012年3月4日期间7次降雨中,岷江下游 (五通桥段)一个小型集水区中水杉人工林、杉木人工林和巨桉人工林穿透水和树干茎流中的4种重金属 (Cd、Cu、Pb、Zn)含量特征.结果表明,3种人工林大气降雨、穿透水和树干茎流重金属含量呈现一致的规律,按平均值大小排列为:Zn>Pb> Cu >Cd.3种人工林穿透水重金属含量差异不显著,水杉人工林与杉木人工林树干茎流中重金属Cd、Cu和Pb含量存在显著差异.巨桉和水杉人工林对重金属Cd和Zn有较强的过滤作用,杉木林和巨桉林对重金属Cu和Pb的过滤作用较强.Pb在3种人工林中的含量均超过国家《生活饮用水卫生标准》.3种人工林穿透水和树干茎流Cd、Pb和Zn的淋溶系数小于1,为负淋溶,杉木树干茎流Cu的淋溶系数大于1,为正淋溶.大气降雨重金属含量与降雨量之间存在显著的负相关关系,水杉人工林穿透水Cu含量、杉木人工林穿透水Cd和Cu含量、巨桉人工林穿透水和树干茎流Cd和Cu含量与降雨量之间存在显著的负相关关系.     

西安泾河夏季黑碳气溶胶及其吸收特性的观测研究

为研究西安泾河夏季黑碳气溶胶及其吸收特性,利用2011年夏季西安远郊泾河大气成分站观测的黑碳气溶胶浓度、颗粒物质量浓度、探空资料、地面气象资料,计算边界层顶高度、气溶胶吸收系数、大气消光系数,导出单次散射反照率,并对其进行分析讨论.结果表明:西安夏季黑碳气溶胶浓度为6.07μg/m3;黑碳气溶胶占颗粒物质量浓度PM1.0比值为21.9%,黑碳气溶胶与颗粒物质量浓度PM1.0、PM2.5、PM10相关系数分别为0.69、0.85、0.91;黑碳气溶胶浓度受城市边界层顶高度影响,风向、风速对泾河黑碳气溶胶的堆积输送有不同作用;气溶胶吸收系数和大气消光系数日变化显著,气溶胶吸收系数占大气消光系数比值范围在12%~30%;季单次散射反照率平均值为0.76,变化范围在0.70~0.84.     

北京地区秋季雾霾天PM2.5污染与气溶胶光学特征分析

利用北京城区和郊区2011年9月1日～12月7日PM2.5质量浓度、气溶胶散射系数(σsca)和黑碳浓度观测资料,研究了雾霾天气条件下北京地区PM2.5污染与气溶胶光学参数的变化特征,并讨论了气象条件的作用.结果表明,北京地区PM2.5污染和气溶胶光学特性受雾霾天气的影响非常明显.PM2.5浓度、σsca和气溶胶吸收系数(σabs)在雾霾期均明显高于非雾霾期,雾霾期日均PM2.5浓度在城区和郊区分别达到97.6μg·m-3和64.4μg·m-3,为非雾霾期日均浓度的3.3和4.8倍.城区高PM2.5浓度造成雾霾类天气出现频率明显高于郊区.轻雾天城区PM2.5浓度、σsca和σabs明显高于郊区,区域输送的影响相对较弱,轻雾和霾天城郊差异较小,区域性特征明显,而雾天σsca城郊非常接近且在各雾霾类天气中相对最高,气溶胶散射能力最强,区域性特征较为明显.气象条件的不同造成各雾霾过程PM2.5浓度、σsca和σabs的空间分布、PM2.5污染及气溶胶消光强度上呈现不同的特点.边界层以上偏南风将南部地区污染物向北京输送,在整层下沉气流作用下使得边界层内污染物浓度增加,加之边界层高度持续稳定在600 m左右,边界层内风速很低,污染物水平、垂直扩散均很弱,造成局地污染物的累积,形成了PM2.5污染和气溶胶消光强度最强的一次雾霾过程.     

室内窗帘竖直火蔓延特性全尺寸实验研究

窗帘的安装方式对其燃烧特性有重要影响.基于9705全尺寸热释放速率实验平台,针对三种不同材质的典型窗帘试样,进行了全尺寸火灾实验.测量了试样在不同褶皱程度下的火蔓延速率、热释放速率、产生烟气的比消光系数等火灾参数,分析比较其相互关系,实验结果可为室内火灾动力学发展的数值模拟和火灾安全设计提供支撑与指导.     

New best estimates for radionuclide solid–liquid distribution coefficients in soils. Part 2. Naturally occurring radionuclides

Predicting the transfer of radionuclides in the environment for normal release, accidental, disposal or remediation scenarios in order to assess exposure requires the availability of an important number of generic parameter values. One of the key parameters in environmental assessment is the solid liquid distribution coefficient, K_d, which is used to predict radionuclide–soil interaction and subsequent radionuclide transport in the soil column. This article presents a review of K_d values for uranium, radium, lead, polonium and thorium based on an extensive literature survey, including recent publications. The K_d estimates were presented per soil groups defined by their texture and organic matter content (Sand, Loam, Clay and Organic), although the texture class seemed not to significantly affect K_d. Where relevant, other K_d classification systems are proposed and correlations with soil parameters are highlighted. The K_d values obtained in this compilation are compared with earlier review data.     

Migratory orientation of red-eyed vireos,Vireo olivaceus,in relation to energetic condition and ecological context

How and when migrants integrate directional information from different sources may depend not only on the bird’s internal state, including fat stores, but also on the ecological context during passage. We designed experiments to (1) examine the influence of stored fat on the decision to migrate and on the choice of migratory direction and (2) investigate how the integration of orientation cue information is tied to energetic status in relation to migration across an ecological barrier. Migratory orientation of red-eyed vireos (Vireo olivaceus) at twilight was recorded using two different techniques, orientation cage experiments and free-flight release tests, during both fall and spring migration. During fall migration, the amount of stored fat proved decisive for directional selections of the vireos. Fat birds chose directions in accordance with migration across the Gulf of Mexico. Lean birds oriented either parallel to the coast line (cage tests) or moved inland (free-flight releases). Whereas only fat birds showed significant responses to experimental deflections of the geomagnetic field, lean birds displayed a tendency to shift their activity in the expected direction, making it difficult to evaluate the prediction that use of the magnetic compass is context dependent. Fat loads also had a significant effect on the decision to migrate, i.e., fat individuals were more likely to embark on migration than were lean birds (true for both cage and release experiments). During spring migration, a majority of experimental subjects were classified as lean, following their arrival after crossing the Gulf of Mexico, and oriented in seasonally appropriate directions. The vireos also showed significant responses to experimental deflections of the geomagnetic field regardless of their energetic status. Free-flight release experiments during spring migration revealed a significant difference in mean directions between clear sky and overcast tests. The difference may indicate a compensatory response to wind drift or possibly a need for celestial cues to calibrate the magnetic compass. Finally, this is the first demonstration of magnetic compass orientation in a North American vireo. Received: 15 December 1995/Accepted after revision: 24 March 1996