北京市交通道路空气中NOx的污染现状及时空变化规律研究

基于2008年及2009年分4个季节对北京市3种类型道路（开阔型、交叉路口型和峡谷型）空气中的NOx的现场监测结果,分析了3种类型道路空气中NOx的污染现状和时空变化规律及影响因素。实验结果表明,昼间北京市各类型街道空气中NOx浓度呈早晚浓度高、中午浓度低的变化规律,NOx浓度随季节和车流量变化较明显。交通道路空气中NO占NOx的分担率高,且有较好的相关性,而NO2分担率较低,与NOx相关性较差。     

黄河三角洲外来入侵物种米草对滩涂鸟类的影响

2005年5,8,10月份分别对黄河三角洲米草分布区与非米草分布区的无棣岔尖、东营市五号桩、小清河口的鸟类作了调查,并辅以2000年黄河三角洲湿地鸟类调查资料,研究了米草入侵对鸟类的影响。结果表明：米草入侵已导致黄河三角洲调查区鸟类种数减少,多样性降低,群落组成和结构发生变化,主要原因是米草入侵使鸟类觅食、栖息生境减少或丧失。     

Water‐Yield Reduction After Afforestation and Related Processes in the Semiarid Liupan Mountains,Northwest China1

Abstract: The increase of coverage of forest/vegetation is imperative to improve the environment in dry‐land areas of China, especially for protecting soil against serious erosion and sandstorms. However, inherent severe water shortages, drought stresses, and increasing water use competition greatly restrict the reforestation. Notably, the water‐yield reduction after afforestation generates intense debate about the correct approach to afforestation and forest management in dry‐land areas. However, most studies on water‐yield reduction of forests have been at catchment scales, and there are few studies of the response of total evapotranspiration (ET) and its partitioning to vegetation structure change. This motivates us to learn the linkage between hydrological processes and vegetation structure in slope ecosystems. Therefore, an ecohydrological study was carried out by measuring the individual items of water balance on sloping plots covered by different vegetation types in the semiarid Liupan Mountains of northwest China. The ratio of precipitation consumed as ET was about 60% for grassland, 93% for shrubs, and >95% for forestland. Thus, the water yield was very low, site‐specific, and sensitive to vegetation change. Conversion of grassland to forest decreased the annual water yield from slope by 50‐100 mm. In certain periods, the plantations at lower slopes even consumed the runon from upper slopes. Reducing the density of forests and shrubs by thinning was not an efficient approach to minimize water use. Leaf area index was a better indicator than plant density to relate ET to vegetation structure and to evaluate the soil water carrying capacity for vegetation (i.e., the maximum amount of vegetation that can be supported by the available soil water for an extended time). Selecting proper vegetation types and plant species, based on site soil water condition, may be more effective than the forest density regulation to minimize water‐yield reduction by vegetation coverage increase and notably by reforestation. Finally, the focuses in future research to improve the forest‐water relations in dry‐land areas are recommended as follows: vegetation growth dynamics driven by environment especially water conditions, coupling of ecological and hydrological processes, further development of distributed ecohydrological models, quantitative relation of eco‐water quota of ecosystems with vegetation structures, multi‐scaled evaluation of soil water carrying capacity for vegetation, and the development of widely applicable decision support tools.     

Uptake of polycyclic aromatic hydrocarbons by Trifolium pretense L. from water in the presence of a nonionic surfactant

A greenhouse study examined plant uptake of phenanthrene and pyrene, as representatives of polycyclic aromatic hydrocarbons (PAHs), from an aqueous solution containing a nonionic surfactant Tween 80. The uptake was conducted with 1.0 mg l(-1) phenanthrene and 0.12 mg l(-1) pyrene under a wide range of Tween 80 concentrations (0-105.6 mg l(-1)). Tween 80 at the test concentrations did not show any apparent phytotoxity toward the growth of red clover (Trifolium pretense L.). At concentrations generally lower than 13.2 mg l(-1), Tween 80 enhanced the plant uptake based on the concentrations and PCFs (plant concentration factors) of these two PAHs. When present at higher concentrations, Tween 80 inhibited the uptake of both PAH compounds by the tested plant. The maximal plant uptake was observed at 6.6 mg l(-1) Tween 80, in which PAH concentrations and PCFs were 18-115% higher than those in Tween 80-free controls. The total mass removal (off-take) of phenanthrene and pyrene by root or shoot increased initially and decreased thereafter with the increase in Tween 80 concentrations. Although shoot biomass was evidently larger than root, the off-take was much higher in root than shoot because of the larger root concentrations of these chemicals. Results from this study show promises for the potential efficacy of enhanced phytoremediation in PAH contaminated sites using surfactant amendment.     

Patterns and sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in surficial sediments of Lakes Erie and Ontario

This study determines spatial trends and congener patterns of 2378-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in surficial sediments of Lakes Erie and Ontario. Sediments are enriched in 2378-PCDFs in Lake Ontario, and the PCDD/F concentrations increased from shallow near-shore sediments towards deep-water depositional zone sediments. In Lake Erie, sediments were dominated by octachlorodibenzo-p-dioxin, and the highest PCDD/F concentrations were observed in the western basin and the southern shoreline of the central basin with a decrease towards the eastern basin and the northern shoreline of the central basin. Principal components analysis revealed that chemical manufacture and disposal of chemical waste along the Niagara River has been a major PCDD/F source to Lake Ontario; while PCDD/Fs in Lake Erie are from multiple sources including industrial sources along the Detroit River, major tributaries along the southern shoreline of the lake, and atmospherically-derived material from the upper lakes and connecting channels.     

Using FTIR to corroborate the identity of functional groups involved in the binding of Cd and Cr to saltbush (Atriplex canescens) biomass

Fourier transform infrared (FTIR) studies were performed to confirm the chemical modification of saltbush (Atriplex canescens) biomass and to provide information about the identity and binding characteristics of the chemical groups responsible for the binding of Cd(II), Cr(III), and Cr(VI). In addition, studies were performed to determine the optimum time for the binding of the three ions by saltbush biomass, and to study the efficiency of HCl and sodium citrate as stripping agents. The metal quantification was performed using inductively coupled plasma optical emission spectroscopy (ICP-OES). The results showed that 10 min or less is enough to achieve the maximum metal binding, and that aqueous solutions of 0.1 mM HCl or sodium citrate were enough to strip more than 80% of the bound Cd. It was determined that more than 70% of the bound Cr(III) was stripped using 0.1 mM HCl. Chemical modification of carboxyl and ester groups on the biomass was performed. The FTIR results confirmed that the esterification of carboxyl groups and hydrolysis of ester groups in the native biomass had occurred. The direct effect of these modifications on the binding properties of the biomass provided strong evidence that the carboxyl functionality is the main group responsible for binding Cd and Cr(III). However, the IR data showed that for Cr(VI), a different type of functional group is involved.     

Preparation of coal slurry with organic solvents

In this study, various organic solvents were used to prepare coal slurries and the rheological and thermal properties of coal-organic solvent slurries were examined. Solvents with molecules containing unpaired electrons (high basicity) show high extraction power and cause swelling of coal. Therefore, coal-organic solvent slurries usually showed higher viscosities compared to coal-water slurry. In addition, coal slurries prepared by alcohols and cyclohexanone demonstrated lower settling rates but a high specific sedimentation volume presumably because these solvents swelled coal particles well and led to the formation of weak gel structures in the bulk. In addition, ethanol and cyclohexanone are capable of breaking a considerable amount of hydrogen bonds in coal and subsequently opening up the structures. Thus, more surface area is available for combustion and the combustion rate of coal slurries was increased.     

飞雪迎春到——记第五届中国国际安全生产及职业健康展览会筹备工作

<正>由国家安全生产监督管理总局主办的中国国际安全生产及职业健康展览会(以下简称五届安展)将于2010年9月1～3日在中国国家会议中心如期举行。近年来,在党中央、国务院领导对安全生产和     

燃烧假人实验室安全监控及应急处理系统设计

针对燃烧假人实验室的安全监控和应急处理要求,根据相关国家标准,设计了感温、感烟、可燃气体探测器、声光报警器,摄像装置、通排风系统、灭火处理系统和水喷淋降温装置,并采取防雷击和防静电措施,实现了对高温、烟雾和燃气泄露等安全隐患的全面监控和处理。     

Failures during construction of a landfill lining: a case analysis.

Two tension failures occurred during the construction of the protection and leachate drainage layers for a geomembrane landfill liner on a slope of 24 degrees to the horizontal. The paper describes and analyses the design and shows that the failures occurred largely because the sequence of construction was altered without due consideration of the consequences. The designers also appeared unaware that there is a difference between the nominal strength of a structural element and its actual in-service strength. This misconception also played a major part in the failures.