基于AHP-TOPSIS法综合评判的保护层开采选择*

为优选首采层作为保护层开采,选取5个一级指标和19个二级指标,建立以AHP（层次分析法）和TOPSIS（逼近理想解排序法）为基础的煤层突出危险性评价模型,通过层次分析法确定各指标的权重,结合逼近理想解排序法分析贴近度并预测出煤层突出危险可能性,并进行现场工业性实验。结果表明:AHP-TOPSIS综合评判法预测优选8号煤层作为保护层开采,并经现场工业性实验验证,瓦斯解放效果较好。该方法结合主观因素和客观因素,避免单一地从主观出发或从客观出发带来的决策失误,并选取大量评价指标,使预测结果更贴合实际情况,可作为优选保护层的理论依据。     

高铁酸钾处理水中十六烷基三甲基溴化铵

室温条件下采用新型氧化剂高铁酸钾(K2FeO4)处理十六烷基三甲基溴化铵(CTAB)模拟废水,探讨反应时间、K2FeO4投加量及体系pH值等因素对CTAB去除率的影响.结果表明,反应时间、K2FeO4投加量及溶液pH值对CTAB的去除率均有不同程度的影响,当反应时间为30 min、K2FeO4投加量与处理液中CTAB质量比为1∶1、溶液pH为7时,K2FeO4对表面活性剂CTAB的去除率达79.4%.在反应过程中,K2FeO4的强氧化性与其还原产物的絮凝作用产生协同效应,其中K2FeO4在完全反应之前CTAB的去除主要依靠K2FeO4的强氧化作用,K2FeO4反应完全之后CTAB的去除则主要依靠K2FeO4还原产物的絮凝作用.同时进一步研究了CTAB被处理前后的红外光谱特征,结果表明CTAB在降解过程中经历了链的断裂并进一步被矿化为无机小分子.化学反应动力学研究结果表明K2FeO4与CTAB的反应符合二级反应动力学规律.     

沼气产生的两步一级反应耦合模型

根据有机物厌氧产生沼气的生化机理,假设沼气通过两步相互衔接的一级反应生成,即复杂有机物的水解酸化反应和简单有机酸的产气反应.根据假设,建立了基于两步一级反应耦合的沼气产气率与产气量随时间变化的数学模型.该模型用统一的数学公式对沼气产气率随时间变化的倒“U”形曲线进行了解释,指出这一过程是两步相互衔接的一级反应相互作用的结果.已知有机物质量,通过拟合或根据经验得出K值后,利用该模型可解出任一时刻有机物的产气率、产气量、最大产气率及其发生的时间.拟合表明,两步反应的反应常数趋于相等.利用该模型可导出已有的Scholl Canyon模型,并可对Palos Verdes模型和Sheldon Arleta模型的经验假设进行解释.      

欧美农药环境降解动力学评估方法比较

农药在环境中的降解行为是评估农药环境安全性的基础,农药的降解动力学通常以一级动力学模型描述。现有的环境暴露模型也均需要输入一级动力学模型的农药在土壤中50%消失时间(DT50)。但有时一级动力学模型不适用于描述农药在环境中,特别是土壤中的降解。因此欧盟和北美自由贸易区已发布了一系列关于使用非一级动力学模型计算DT50的导则。介绍了欧美降解动力学评估方法,并用多组降解数据比较了2种评估方法的区别。     

关于城市规划中规划环评的探讨

城市规划是将持续发展、科学发展作为基础,对于城市发展中的经济结构、环境影响等内容加以规划,以发挥指导规范城市发展的作用。在城市规划的编制过程中要对环境影响加以评价。本文以城市规划与环境评价为出发点,提出规划环境影响评价存在的几点问题及解决思路,在更大的范围内保证城市规划的合理性,为政府相关部门科学决策提供依据。     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

OXYGEN SAG EQUATION FOR THREE-HALVES ORDER BOD REACTION1

Several published BOD data sets are examined to show that approximately half of them are described best in the least squares sense by treating the BOD equation as being of the three-halves order instead of first order. A dissolved oxygen (DO) sag equation for a stream is developed in which the BOD is described as a three-halves order reaction. The time when the minimum DO concentration occurs is calculated numerically. The DO sag model applied to example problems shows that an increase in the BOD reaction rate constant results in a smaller minimum DO concentration and a decrease in the time to reach the minimum DO.     

补充碳源对厌氧生物处理2,4,6-三氯酚的影响

利用半连续投料的驯化方法对３种不同来源的生物污泥厌氧降解２,４,６－三氯酚（２,４,６－ＴＣＰ）过程中补充碳源的影响进行了研究。结果表明,经过５０～６０ｄ的驯化,取自有机化工厂和造纸七厂的２种污泥的比降解速度（氯酚／ＳＳ）分别达到了０．６ｍｇ／（ｇ·ｄ）和０．２ｍｇ／（ｇ·ｄ）,而取自北京啤酒厂ＵＡＳＢ反应器的污泥的比解速率只有０．０３ｍｇ／（ｇ·ｄ）～０．０５ｍｇ／（ｇ·ｄ）。补充碳源对北京啤酒     

论结构、秩序和牵制共同决定系统功能

论述了“结构、秩序和牵制共同决定系统功能”的理论,并通过丰富的案例阐述了该理论在安全管理系统的应用。