大气环境及腐蚀性

根据近年来国内外对大气环境和腐蚀性的研究成果．描述了大气环境及腐蚀性的研究状况,介绍了国际标准化组织的分类分级标准和我国大气环境的腐蚀性的分类分级的探讨性研究以及大气腐蚀图的研究。     

道路降尘与扬尘PM_(10)排放的关系研究

道路扬尘是城市大气颗粒物主要来源之一,文章主要分析呼和浩特城区道路降尘排放、扬尘PM10排放强度并研究二者之间的关系。对呼和浩特30条典型道路进行了降尘监测,并在降尘监测期间对道路尘负荷进行了采样分析,同时记录车流量和车辆构成数据,应用AP-42排放因子模型计算PM10排放强度,分析道路降尘与PM10排放强度之间的关系。结果发现,道路降尘值为外环路>主干路>次干路>支路>胡同,分别为76.3、36.1、31.7、25.8和19.0 t(/km.230d),背景值为9.4 t(/km.230d);外环路、主干道、次干道、支路和胡同的PM10排放强度平均值分别为178、169、130、100和11 kg(/km.d);降尘值DF与道路扬尘PM10排放强度呈现较好的正相关关系,道路扬尘PM10排放强度可以用降尘表示为Q=2.6×(DFr-DFb)。     

α-Fe2O3砂芯微球制备及紫外辅助下活化PMS降解AO7

以FeCl₃为原料，尿素为沉淀剂，抗坏血酸为还原剂，聚乙烯吡咯烷酮为结构导向剂，纳米碳粉为模板，水热法制备了一种新型α-Fe₂O₃砂芯微球.通过透射电镜（TEM）、扫描电镜（SEM）、X射线衍射（XRD）和比表面积及孔径分析（BET/BJH）等手段对其结构和性能进行表征.结果表明新型α-Fe₂O₃砂芯微球尺寸均匀，直径为50μm左右，是由直径40nm"米粒状"纯相α-Fe₂O₃自聚而成，S_BET为25.45~32.46m²/g.在紫外（UV，高压汞灯）辐射下能够活化过硫酸盐（PMS）产生强氧化性的硫酸根自由基（SO₄^-·）.40min内AO7的降解率可达98.6%，采用电子自旋共振（ESR）技术鉴定了主要的活性氧自由基（ROS）为SO₄^-·.此外发现PMS作为一种电子捕获剂，能有效抑制光生电子（e_CB^-）和空穴（h_VB⁺）的复合，AO7能直接和h_VB⁺、SO₄^-·和羟基自由基（OH·）反应而迅速被氧化降解；α-Fe₂O₃回收重复使用10次，仍可以达到80%以上的去除率.通过考察α-Fe₂O₃投加量、PMS浓度、初始pH值、阴离子和初始AO7浓度等不同条件对AO7降解率的影响，发现在初始pH值为7.0，α-Fe₂O₃的投加量为1.0g/L，PMS浓度为0.3g/L时，40min内对AO7的降解率可以达到99%以上；阴离子CO₃^2-、NO₃^-以及Cl^-对该体系均有不同程度的促进作用.     

北方干旱化和土地利用变化对泾河流域径流的影响

论文以在黄土高原上发育,流经中国北方干旱、半干旱地区的黄河二级支流--泾河为研究对象,基于20世纪八九十年代的土地利用影像资料,以及泾河流域1970~2002年的气候、水文资料,采用美国农业部开发的分布式流域水文模型SWAT,分析了20世纪80~90年代泾河流域的降雨量和径流量的变化。从80到90年代,流域年降雨量呈逐年递减趋势,80年代多年平均月降雨量明显大于90年代多年平均月降雨量,尤其在7~9月,平均降雨量明显减少。受气候干旱化和土地利用/覆被变化的共同作用,80~90年代,流域多年平均年径流减少了8.92m³s^-1。为了区分气候变化和土地利用变化对流域径流的影响,采取分别固定气候因子与土地利用/覆被变化因子的方法,将模拟情景输入模型,定量区分气候和土地利用/覆被变化对流域径流的影响方式和程度。结果表明,气候干旱化趋势使流域多年平均年径流减少28.08m³s^-1,为气候、土地利用/覆被变化共同影响径流变化量的314.80%;土地利用/覆被变化使流域多年平均年径流增加26.57m³s^-1,为气候、土地利用/覆被变化共同影响径流变化量的297.87%。     

2,2',4,4'-四溴联苯醚的好氧微生物降解

从北京高碑店污水处理厂活性污泥中筛选出1株能好氧降解2,2’,4,4’-四溴联苯醚(BDE-47)的细菌,并对其降解特性及有关蛋白质进行分析,目的是了解好氧条件下BDE-47的微生物降解机制.BDE-47降解菌通过平板划线法获得,其16S rDNA与不动杆菌(Acintobacter sp.)的相似度最大,为90%.采用250 mL锥形瓶研究了所得菌对BDE-47的降解情况,在BDE-47初试浓度为146μg.L-1的条件下,经过63 d的培养,所得菌降解了45.44%的BDE-47,降解产物主要为4-OH-联苯醚,菌量增加了7倍左右.分别以BDE-47和酵母提取物为碳源培养所得菌2周,然后各自提取蛋白质,通过蛋白质双向电泳及质谱检测,发现了与BDE-47降解有关的一些特异蛋白质.本研究表明,在好氧条件下,细菌可以BDE-47为碳源生长,其过程涉及多种蛋白质的作用.     

2,2',4,4'-四溴联苯醚高效好氧降解菌的鉴定及其降解路径

2,2',4,4'-四溴联苯醚(BDE-47)是环境和生物体中普遍检出且生物毒性较大的一种多溴联苯醚同系物.本研究从广东省贵屿镇电子垃圾拆解厂周边采集的农田土壤中分离出一株BDE-47的高效好氧降解菌GYP1,考察了其对BDE-47的降解性能、降解路径及不同的环境因素对菌株降解BDE-47的影响.根据菌株形态特征、16S r DNA基因序列及系统发育树分析,将该菌鉴定为伯克霍尔德菌(Burkholderia cepacia).结果表明,菌株GYP1在好氧条件下能够利用BDE-47为唯一碳源生长,在BDE-47初始质量浓度为1 mg·L~(-1)、温度为30℃、摇床转速为150r·min~(-1)的条件下避光培养4 d,该菌株对BDE-47的降解率可达到82.4%.菌株GYP1在15~35℃和p H=4.0~7.0的环境条件范围内对BDE-47均能保持良好的降解性能,但外加蔗糖、酵母粉、联苯醚等碳源会明显抑制其对BDE-47的降解.在菌株GYP1对BDE-47的降解过程中检测到6-OH-BDE-47、5-OH-BDE-47、4'-OH-BDE-17、2'-OH-BDE-3这4种羟基多溴联苯醚及2,4-二溴苯酚,证明菌株GYP1对BDE-47的好氧降解机理主要是羟基化过程.     

Simulation of three-stage operating temperature for supersaturation water-based condensational growth tube

In order to realize accurate dynamic control of supersaturation and to study condensation growth characteristics of nanoparticles through different levels of super saturation,a series of parametric analyses and systematic comparisons between two-stage and three-stage operating temperature designs were simulated with COMSOL Multiphysics.The simulation results showed that the three-stage operating temperature did not change peak supersaturation compared with two operating temperatures,and the three-stage operating temperature was superior in decreasing the amount of water vapor and the temperature,thus lowering particle loss and variation in detection and collection.The peak supersaturation level increased by 0.3 as the flow rate increased from 0.6 to 2.0 L/min,but the supersaturation peak moved from 0.0027 z0 to 0.08 z0(i.e.,the growth time and the final size decreased by 40%).Peak supersaturation increased as the temperature difference increased or the temperature difference window was shifting left,and minimum activation size decreased.Shifting the 70℃temperature difference window from 9℃,79℃-1℃,71℃for the condenser and initiator temperatures resulted in peak supersaturation in the centerline being above 5.8,and the activation size changed as low as 1 nm.Experiments with flow rates varying by a factor of 2.5(from 0.6 to 1.5 L/min) resulted in a final size decrease of 43%(from 3.2 to 1.8 μm),and experimental results of outlet particle size distributions were equivalent with theoretical analysis as the operating temperature was changed.     

Long-Term Impacts of Land-Use Change on Non-Point Source Pollutant Loads for the St. Louis Metropolitan Area, USA

A land-use-change simulation model (LEAM) and a non-point-source (NPS) water quality model (L-THIA) were closely coupled as LEAMwq in order to determine the long-term implications of various degree of urbanization on NPS total nitrogen (TN), total suspended particles (TSP), and total phosphorus (TP) loads. A future land-use projection in the St. Louis metropolitan area from 2005 to 2030 using three economic growth scenarios (base, low, and high) and a long-term precipitation dataset were used to predict the mean annual surface runoff and mean annual NPS pollutant loads in the region. Results show mean annual TN increases of 0.21%, 0.13%, and 0.14% by 2030 compared to 2000 under the base, high, and low scenarios, respectively. TSP and TP showed similar trends with different magnitudes. Corresponding changes in annual mean surface runoff were shown to be lower than expected, which might be attributed to the small-scale conversion pattern of land uses. In the most dramatic change (high growth) scenario, the runoff would increase across time but at varying rates, and temporal pollutant loads would result in a more complicated pattern than in the other scenarios. This is attributed to the complex interactions between event mean concentrations of pollutants and the magnitude of changes in land-use acreages. By integrating L-THIA with LEAM, LEAMwq was found to be a useful planning tool to illustrate in a quick and simple manner how future water quality is connected to decision-making on future land-use change.     

Use of Remote-Trip Cameras for Wildlife Surveys and Evaluating the Effectiveness of Conservation Activities at a Nature Reserve in Sichuan Province,China

Monitoring the effectiveness of management activities within reserves is always a complicated task. When the focus of management activities is mammals, it is difficult to monitor their populations in a way that is rapid, effective, and inexpensive. We report on a mammal survey of a reserve in southwest China using remote-trip cameras. We surveyed 329 locations over 2 field seasons in 2002 and 2003. Sixteen species of mammals were detected with these cameras, with four species documented for the first time. After accounting for variation due to slope, aspect, elevation, and habitat type, the distribution of six species was positively associated with the location of conservation stations and/or patrolling routes. Species of medium-sized mammals are excellent candidates for monitoring programs based on these cameras, due to their relative abundance, sufficient size to be detected by the camera units, and sensitivity to human activity. The distribution of mammals relative to management efforts is a relatively rapid means to assess reserve effectiveness. The repeat use of the cameras as part of a monitoring plan should provide a quantifiable measure of reserve effectiveness.     

大型钢铁企业典型工序碳排放系数的确定方法探讨

为准确合理地确定适合于钢铁行业实际的碳排放系数,通过碳平衡算法求出了各工序的碳排放量,然后按碳排放系数的定义反算出了各工序的碳排放系数.同时,通过对某大型钢铁企业焦化、烧结、炼铁3个典型工序的原料产能的实测数据调查,首先基于碳平衡方程计算出典型工序的碳排放量,然后由碳排放量计算其碳排放系数.最后以该大型钢铁企业2009年的调查数据为例,按本方法计算出的焦化、烧结、炼铁工序的碳排放系数分别为0.518、0.210、1.375,与IPCC提供的默认值(0.56、0.20、1.35)极为吻合.这一结果表明,该方法用于我国钢铁行业碳排放系数体系的建立是可行的.