基于车载测试的国VI重型柴油车CO2和NOx排放研究

利用便携式尾气测量系统（PEMS）对一辆国Ⅵ重型柴油车在北京（低温）和厦门（常温）分别进行0、50%和90%负载的实际道路排放测试.结果表明,国Ⅵ重型柴油车CO₂基于功率平均排放为685 g·kWh-1,行驶阶段CO2基于里程的排放因子平均为662.35 g·km-1.NOx排放比国Ⅵ标准限值低68.3%.NOx基于功率的排放因子为82.6 mg·kWh-1,较国V下降98.6%,行驶阶段NO_x基于里程的排放因子较国V下降99%,国Ⅵ重型柴油车实际道路排放控制效果良好.研究发现,较高的NO_x排放主要集中在急加速段,并在长下坡结束时,出现NO_x排放峰值.此外,6次测试冷启动NO_x排放占整个测试阶段总排放的23.5%～56.7%.CO₂和NO_x排放随速度增加呈下降趋势,50%负载和90%负载时NO_x的排放因子接近10%负载的2倍.低温时CO₂和NOx排放因子较常温时分别升高17.7%和4.5%,...     

锅炉的定性定量安全评价方法研究

本文对锅炉危险、有害因素进行了分析,并对其危险性作了定性、定量评价,最后在分析评价和事故原因的基础上,提出了相应的对策措施.     

氮磷生态拦截集成技术治理湖泊岸区农业面源污染分析研究

农业面源污染是造成湖泊水体富营养化的重要原因之一,中国湖泊边岸广泛分布的自然村落使污染问题日益严峻,氮磷生态拦截集成技术已经作为一种经济有效的技术措施逐渐得到推广应用.通过分析国内外所采用的几种适合湖泊岸区的氮磷生态拦截技术,不同区域采用的氮磷生态拦截集成技术要因地制宜,需结合当地的农作物种植、植物种类分布、地形地貌、气候环境等因素,科学地选择净化植物与处理工艺,才能取得较好的治理效果.     

富硅肥料和水分管理对稻米镉污染阻控效果研究

在已筛选出的施硅方式(基施和叶面喷施相结合)基础上,选择典型单一镉污染稻田土壤(pH=4.97,总Cd 4.1 mg·kg~(-1)),并结合2种稻田水分管理方式,进一步开展不同水肥管理方式对常规早稻(湘早籼45)和杂交晚稻(丰源优299)的3个生育期内各部位中Cd含量及成熟期生物量的影响研究.实验设计4个处理:不施硅肥+常规间歇淹水措施(CK)、不施硅肥+全生育期淹水措施(W)、2种硅肥配施+常规间歇淹水措施(SiLsi)、2种硅肥配施+全生育期淹水措施(SiLsi+W).结果表明,4个处理下,早晚稻试验结果基本一致,但各试验处理对晚稻的阻镉效果更加明显;与CK相比,各处理都能显著降低水稻籽粒中Cd的含量且不会明显影响水稻产量,其中以SiLsi+W对籽粒的降Cd效果最佳(晚稻精米中Cd的含量为0.12 mg·kg~(-1),达到了国家粮食安全生产标准:Cd0.2 mg·kg~(-1)),分别使晚稻谷壳、糙米和精米的降Cd幅度达到93.65%、86.70%和91.18%,W和Si Lsi处理的降Cd效果次之.因此,SiLsi+W可作为一种有效的稻米镉污染控制技术.     

黄土高原自然植被恢复对土壤质量的影响

本文从土壤物理、化学和生物因子等方面综合考虑,运用土壤质量综合指数模型,计算土壤质量综合指数。定量化评价黄土高原自然植被恢复对土壤质量的影响,期望为该区植被恢复对土壤质量的影响提供理论指导,促进当地生态环境重建工作的进展。研究结果表明:1)与农田相比,植被恢复对土壤容重、水稳性团聚体、pH、电导、有机碳、全氮和微生物量碳、氮影响显著,对含水量、无机碳含量影响居中,对土壤粘粒、砂粒含量、全磷影响不显著。2)与农田相比,植被恢复后,土壤质量综合指数(SQI)值在0~10 cm和10~20 cm均有较大幅度的提高,0~10 cm比10~20 cm增幅更大。3)当地农田土壤质量处于低(V)水平,草地处于较低(Ⅳ)水平,灌木林和混交林处于中等(Ⅲ)水平,山杨和辽东栎林处于较高(Ⅱ)水平。草地恢复对于提高土壤质量的效果较差,林地恢复对提高土壤质量的效果相对最佳。     

流动注射测定阴离子表面活性剂不确定度的评估研究

流动注射测定阴离子表面活性剂具有分析速度快、准确度和精密度高、进样量少、对操作人员危害较小等优点.为了能够掌握流动注射测定阴离子表面活性剂数据的分散性,通过对量器体积测量、标准溶液配置、样品测量重复性、工作曲线拟合、测量仪器5个方面的不确定影响进行分析,从而得出流动注射测定阴离子表面活性剂的标准不确定度和扩展不确定度.最终测得阴离子表面活性剂测量结果为(0.489±0.016 mg/L);k=2.     

稀有鮈鲫Ras信号通路相关基因的克隆、序列分析及其组织分布

Ras基因是一类在生物进化过程中较为保守的原癌基因,在多种细胞生命活动中起到细胞增殖、分化和细胞骨架构建等重要作用。本文克隆了稀有鮈鲫Ras信号通路相关的k-ras、n-ras、pik3cd、pin1和raf1基因的部分c DNA片段,并分析了其序列。序列分析结果表明,k-ras的氨基酸序列与鲤鱼相对应的氨基酸序列同源性最高,为99%;n-ras、pik3cd、pin1和raf1的氨基酸序列均与斑马鱼相对应的氨基酸序列同源性最高,分别为99%、87%、96%和97%,结果表明稀有鮈鲫与鲤鱼、斑马鱼的亲缘关系较近。组织表达分析表明,k-ras、n-ras、pik3cd、pin1和raf1基因在肝脏、鳃、肾脏、脑和性腺等组织中具有表达差异性。本文为研究环境污染物对鱼类致癌作用机制和安全性评估提供分子生物学基础和科学依据。     

Sediment nutrient flux in a coastal lake impacted by diverted Mississippi River water

The internal nutrient load from bottom sediment to the water column of a Louisiana Barataria Basin lake (Lake Cataouatche) receiving diverted Mississippi River water was determined. Dissolved reactive phosphorus (DRP), ammonium (NH₄-N) and nitrate (NO₃-N) flux from sediment to water column were measured. The DRP flux averaged-0.22 mg m^-2 d^-1 under aerobic water column conditions, as compared with that 3.29 mg m^-2 d^-1 under anaerobic conditions. The average NH₄-N released under anaerobic conditions (1.42 mg m^-2 d^-1) was significantly greater than rates under aerobic conditions (-0.02 mg m^-2 d^-1), indicating a strong relationship between nutrient flux and oxygen availability in the water column. The average NO₃-N flux was 2.13 mg m^-2 d^-1 under aerobic conditions as compared with-0.24 mg m^-2 d^-1 under anaerobic conditions in the sediment-water column. When the water column maintained under anaerobic conditions was switched to aerobic conditions, the DRP, NH₄-N, and NO₃-N concentrations in overlying water decreased rapidly over a short period of time. The mean annual internal DRP and NH₄-N load from the sediment to the overlying water was estimated to be 69.26 and 29.9 tonnes (Mg) yr^-1 respectively, which represents a significant portion of the total nutrient load to the Lake. Results demonstrate that the internal flux of nutrients from sediments can contribute a significant portion of the total nutrient load to the water column and should be considered in decisions on impact of nutrient in diverted Mississippi River on water quality of Barataria Basin.     

房地产开发项目环境影响评价内容的探讨

根据房地产开发项目的特点，阐述了房地产开发项目类型、工程概况和施工期、运行期分别对环境产生的不良影响，着重分析施工期扬尘、运行期废水污染情况，以及减绶该不利影响的措施，最后总结房地产开发项目环境影响评价还须进一步探讨的问题。     

Concentrations, sources and spatial distribution of polycyclic aromatic hydrocarbons in soils from Beijing, Tianjin and surrounding areas, North China

The concentrations, profiles, sources and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) were determined in 40 surface soil samples collected from Beijing, Tianjin and surrounding areas, North China in 2007, and all sampling sites were far from industrial areas, roadsides and other pollution sources, and across a range of soil types in remote, rural villages and urban areas. The total concentrations of 16 PAHs ranged from 31.6 to 1475.0 ng/g, with an arithmetic average of 336.4 ng/g. The highest PAH concentrations were measured in urban soils, followed by rural village soils and soils from remote locations. The remote-rural village-urban PAH concentration gradient was related to population density, gross domestic product (GDP), long-range atmospheric transport and different types of land use. In addition, the PAH concentration was well correlated with the total organic carbon (TOC) concentration of the soil. The PAH profile suggested that coal combustion and biomass burning were primary PAH sources.