Henry's law constants of chlorinated solvents at elevated temperatures

Henry’s law constants for 12 chlorinated volatile organic compounds (CVOCs) were measured as a function of temperature ranging from 8 to 93 °C, using the modified equilibrium partitioning in closed system (EPICS) method. The chlorinated compounds include tetrachloroethylene, trichloroethylene, cis-1,2-dichloroethylene, vinyl chloride, 1,1,1-trichloroethane, 1,1-dichloroethane, 1,2-dichloroethane, chloroethane, carbon tetrachloride, chloroform, dichloromethane, and chloromethane. The variation in Henry’s constants for these compounds as a function of temperature ranged from around 3-fold (chloroethane) to 30-fold (1,2-dichloroethane). Aqueous solubilities of the pure compounds were measured over the temperature range of 8-75 °C. The temperature dependence of Henry’s constant was predicted using the ratio of pure vapor pressure to aqueous solubility, both of which are functions of temperature. The calculated Henry’s constants are in a reasonable agreement with the measured results. With the improved data on Henry’s law constants at high temperatures measured in this study, it will be possible to more accurately model subsurface remediation processes that operate near the boiling point of water.     

恩施地区近54年降水量变化特征分析

基于湖北省恩施州的4个气象站点（巴东、绿葱坡、恩施、来凤）以及周边的3个站点（万州、奉节、五峰）近54 a逐年的降水量数据,利用气候倾向率法、ARCGIS空间分析法、小波周期分析法（Wavelet Analysis）和Mann Kendall突变分析法分别对研究区的降水量的时空变化、周期变化、突变进行了分析。研究表明：湖北恩施地区近54 a降水量呈现出波动式的下降趋势,20世纪90年代后尤为明显。从时间变化来看,70年代和90年代的降水量的下降量要比其它年代降水增加量要大;四季变化中除了冬季降水量呈现出较为明显的上升趋势外,其它3个季节降水量呈现较为明显的下降趋势。从空间变化来看,降水量最多的区域主要集中在绿葱坡地区,最少的区域主要集中在东北部的巴东和西北部利川的部分区域,形成了“一高两低”且有东北部向西部逐渐减少的分布态势     

微型舱模拟室内环境中活性炭净化甲醛的能力

利用微型实验舱(0.04 m3)模拟室内甲醛环境进行活性炭吸附实验,研究吸附后甲醛浓度随时间的变化趋势,计算活性炭对甲醛的净化效率、吸附速率和饱和吸附量,探索活性炭对室内甲醛的吸附规律.研究发现,当甲醛含量为0 ～0.40 mg,活性炭用量为0.5g时,舱内甲醛浓度随时间延长呈指数递减变化趋势,吸附后0～0.5 h甲醛浓度递减得最快,0.5～2h递减速度变缓,2～4h甲醛浓度基本上保持不变;研究E0A1、E1A4曲线斜率K及活性炭甲醛净化效率发现,每次吸附过程活性炭吸附2h可达到吸附平衡,活性炭进行3次吸附平衡即可达到吸附饱和,每次实验第一次吸附过程、每次吸附过程前半小时活性炭对甲醛的吸附能力最强;活性炭的吸附速率在吸附初期迅速降低,最后趋近于0;等量椰壳活性炭在一定浓度的污染物环境中饱和吸附量是个定值.说明使用活性炭净化室内甲醛有一定的规律可循.     

研发能力与研发效率的比较研究——以河南省大中型工业企业为例

通过构建大中型工业企业研发能力与效率的评价指标体系,运用因子定权法,对河南省18个地市的大中型工业企业研发能力与效率区域差异进行了测度和分析。研究发现,河南省大中型工业企业研发能力与效率整体协调性差,部分地区研发能力的获取是以牺牲研发效率为代价的;自主创新支撑能力、资本投入、环境约束是影响河南省大中型工业企业研发能力与效率的关键因素,而人力资本投入权重相对较小,说明河南省大中型工业企业的研发软实力有待提高。     

城市绿化法初论:概念与立法目的

城市绿化法是指调整人们在城市绿化活动中产生的社会关系的法律规范总和。它应以保障人的健康和福利、促进城市可持续发展、保障和促进城市绿化事业的发展、保护和改善生态环境、美化生活环境为立法目的。城市绿化法的立法目的既是城市绿化法创制和适用的前提和根本,也是研究城市绿化法的逻辑起点。     

Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil

Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, ρ(b), and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D(p)/D(o), ratio of gas diffusion coefficients in soil and free air) and air permeability (k(a)) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting ρ(b) values ranging from 1.40 to 2.10 g cm(-3). Results showed that D(p) and k(a) values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2mm) under variably-saturated conditions for a given soil-air content (ε), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D(p) and k(a) was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D(p)/D(f), the ratio of measured D(p) to D(p) in total porosity (f), (ii) for air permeability k(a)/k(a)(,pF4.1), the ratio of measured k(a) to k(a) at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content (ε) to total porosity (f) (air saturation). Based on the normalized parameters, predictive power-law models for D(p)(ε/f) and k(a)(ε/f) models were developed based on a single parameter (water blockage factor M for D(p) and P for k(a)). The water blockage factors, M and P, were found to be linearly correlated to ρ(b) values, and the effects of dry bulk density on D(p) and k(a) for both '+gravel' and '-gravel' fractions were well accounted for by the new models.     

环境污染的法律控制路径论说

市场失灵决定法律作为国家手段必须介入环境污染控制.无论是传统法还是针对具体环境污染问题而制定的单项环境法,都因其"滞后性和片面性",难以收到良好的控制效果.为有效应对环境问题,必须贯彻"事先预防、全面控制"的理念,制定以"计划性、综合性"为特点的环境基本法.鉴于环境基本法在各国控制环境污染的实践中成效显著,应坚持中国《环境保护法》的环境基本法定位,并随着环境问题的发展,不断完善之.     

浅论我国环境法与外商投资的关系

为调整外商中的投资环境保护问题,我佃环境法已经形成了一个包括宪法性规范,专项单行立法,地方性法规及国际公约等多层次的法律框架。我国将外商投资项目分为鼓励允许、限制禁止四类,并规定了外商投资应遵循的若干环境管理措施。但总体上看我国环境法还存在立法和执法缺陷,亟待完善。     

浅议我国环境保护产业政策

从狭义和广义两方面介绍了环境保护产业的概念,综述了我国与环境保护产业相关的法律、法规、方针以及符合我国国情的环境保护产业的政策体系,分析了环境保护产业存在的问题,提出了我国环境保护产业发展的建议。