Characteristics of mass distributions of aerosol particle and its inorganic water-soluble ions in summer over a suburb farmland in Beijing

Agricultural activity is one of the most important sources of aerosol particles. To understand the mass distribution and sources of aerosol particles and their inorganic water-soluble ions in a suburb farmland of Beijing, particle samples were collected using a microorifice uniform deposit impactor (MOUDI) in the summer of 2004 in a suburb vegetable field. The distribution of the particles and their inorganic water-soluble ions in the diameter range of 0.18–18 μm were measured. The dominant fine particle ions were SO₄ ^2?, NO₃ ^?, and NH₄ ⁺. The association of day-to-day variation of the concentration of these ions with temperature, humidity, and solar radiation suggested that they are formed by the reaction of NH₃ released from the vegetable field with the acid species produced from photochemical reactions. Fine particle K⁺ is likely from vegetation emission and biomass burning. Coarse particles like Ca²⁺, Mg²⁺, NO₃ ^?, and SO₄ ^2? are suggested to come from the mechanical process by which the soil particle entered the atmosphere, and from the reaction of the acid species at the surface of the soil particle. The results show that fertilizer and soil are important factors determining the aerosol particle over agricultural fields, and vegetable fields in suburban Beijing contribute significantly to the aerosol particle.     

五里塘生态农场有机废弃物的资源化生态工艺

上海市松江县五里塘生态农场以沼气工程、氧化沟和鱼塘围网养鸭为主的生态工程,有效地利用了农场产生的大量禽畜粪便并解决了沼液,沼渣的二次污染问题;在沼气池上建玻璃温室保温,使沼气池能正常越冬从而得以周年运转.生态工程的建立,取得了良好的经济、生态和环境效益.     

五氯酚对鲫鱼肝脏的氧化损伤

将鲫鱼暴露于浓度分别为 0 .0 0 16、0 .0 16、0 .16mg·L-1的PCP溶液 15d ,同时做空白对照 ,测定鲫鱼肝脏的SOD、GSH、MDA以及NO、NOS等指标。试验结果表明 ,0 .16mg·L-1组处理的鲫鱼第 13天全部死亡。与对照相比 ,在 0 .0 0 16mg·L-1浓度下 ,PCP提高了鲫鱼肝脏MDA和NO含量 ,GSH含量降低 ,SOD活性被抑制 ,NOS活性有所升高。在 0 .0 16mg·L-1浓度组 ,PCP对几个指标的影响比 0 0 0 16mg·L-1组大 ,与对照相比 ,具有显著差异 ,说明PCP暴露可导致鲫鱼肝脏的氧化损伤     

On the random placement hypothesis

A traditional method of summarizing spatial distribution of species is the observed species-area curve. Often the observed species-area curve is surprisingly close to the expected species-area curve under the hypothesis of random placement of individuals. This has been used as evidence supporting the hypothesis. In this paper, we argue that using the observed species-area curve to test the general random placement hypothesis is highly inefficient. We present a testing method based on the classical ² test for over-dispersion which is not only more efficient but also applicable to situations where complete abundance information are unavailable. We also discuss three alternatives of the hypothesis. The focus of this paper is on these and other general issues relevant to communities of different types. No applications are included in this paper.     

Degradation of 4-aminophenol by hydrogen peroxide oxidation using enzyme from Serratia marcescens as catalyst

This paper reports on the degradation of 4-aminophenol using hydrogen peroxide as oxidizer and the enzyme from Serratia marcescens AB 90027 as catalyst. The effecting factors during degradation and the degrading mechanism were studied. Also, the location of the enzyme in the cell, which could catalyze the degradation of 4-aminophenol, was analyzed. The results showed that to degrade 50 mL of 4-aminophenol whose concentration was 500 mg/L, the optimal conditions were: volume of H₂O₂ = 3 mL, temperature = 40–60°C and pH = 9–10. In the degradation process, 4-aminophenol was first converted to benzoquinone and NH₃, then organic acids including maleic acid, fumaleic acid, and oxalic acid were formed, and then finally CO₂ and H₂O were generated as final products. The enzyme that could catalyze the degradation of 4-aminophenol was mainly extracellular enzyme.     

上喷淋气体净化技术研究

以水洗除尘技术为基础,针对下喷淋洗涤净化技术的不足,提出了反传统的向上喷淋洗涤净化的理论及液滴二次细化技术,使洗涤液滴在净化段的运行停留时间得以成倍提高,洗涤循环液的消耗量大幅度降低,显著提高了净化除尘效率和可靠性,又降低了循环泵的运行电耗,综合技术经济效益高。     

固液界面吸附机制与模型——“环境水质学前沿专栏”序言

固液界面吸附是环境水化学及水处理技术研究中的一项重要内容.本文阐述了目前固液界面吸附研究方面取得的主要进展,对吸附剂表面性质、吸附络合物形态、表面反应描述中使用的一些重要实验技术、理论计算方法和模型模拟手段进行了系统的介绍,并展望了固液界面吸附研究的发展趋势.表面表征技术、理论计算及表面络合模型的发展、应用和结合有力地促进了人们对各种固液界面体系吸附机制的深入理解,对于阐明污染物在水环境中迁移转化规律,及开发新型吸附剂有着重要的科学意义.     

生物－非生物煤炭脱硫新技术的研究

对生物－非生物煤炭脱硫的原理、菌种及操作条件等问题进行了探讨和实验研究。实验结果表明非生物－乳化技术与生物脱硫技术结合应用，大大提高了脱硫效率。在２—３ｄ内煤炭黄铁矿硫去除率为５３．２％，总硫去除率为３２．７％。而且改变煤粒度或反应条件均会改变总硫去除率，最高可达４７％（２ｄ）。     

对甲醛法测定二氧化硫的疑议

采用3种方法分别制作的SO2校准曲线无显著差异，且斜率一致，测定标准样品均在保证值范围之内，说明省略标定NaSO3的过程是可行的，同时对甲醛法给定的浓度范围和斜率值进行质疑。     

盐雾加速腐蚀试验相对于石家庄大气环境试验的加速倍率研究

以45钢、A3钢、炮钢、20钢为金属试样,研究它们在中性盐雾加速试验及石家庄大气环境暴露试验中腐蚀失重与时间的变化规律。试验结果表明,两种试验方法具有较好的相关性和重现性,盐雾加速腐蚀试验相对于石家庄2002-2003全年大气环境试验的加速倍率约为30。