固定底物酶底物法与多管发酵法和快速纸片法测定水中粪大肠菌群(耐热大肠菌群)的比较

采用酶底物法和多管发酵法及快速纸片法,比对分析了分组环境水样中的大肠菌群,采用无菌水和标准菌种ATCC 25922(大肠埃希菌)标准菌种检验3种方法的假阳性率与假阴性率,结果表明,固定底物酶底物法与多管发酵法用于水中粪大肠菌群(耐热大肠菌群)检测结果具有一致性。     

美欧中印“国家自主贡献”目标的力度和公平性评估

基于气候公平的不同原则,采用动态的衡量指标,建立了公平分配未来碳排放空间的综合性框架,计算了基数、平等、能力、责任和混合方案下2010~2100年全球累积碳排放配额的地区分布,并评估了美欧中印“国家自主贡献（Intended Nationally Determined Contribution,INDC）”目标的力度,提出了各国减排目标力度应当增加的程度.结果表明：美欧中印总体的INDC力度离实现2℃目标仍有差距,不同方案下的排放差距为8.0~9.6Gt CO₂,超出2030年2℃目标下全球排放的比例为20%~24%.在各自最为有利的方案下,中印能满足实现2℃目标的公平分配方案的低限要求.而在所有方案下美欧距离实现2℃目标的公平分配要求均有差距,需要进一步提高力度.公平指标的动态和静态衡量方法,以及历史责任计量起始年的选取,对公平分配的结果影响很大.     

Effect of pH on the sonochemical degradation of organic pollutants

An increasing number of organic compounds are manufactured, consumed, and discarded every year. Incomplete destruction of these compounds in wastewater treatment plants leads to pollution of natural waters, posing great health and ecological concerns. Ultrasound, as an emerging advanced oxidation technology, can quickly and effectively degrade organic pollutants in waters. To improve removal efficiency of organic pollutants in an ultrasonic system, operational parameters, especially pH, have been frequently evaluated and optimized. This review show that pH-induced changes in volatility, hydrophobicity and Coulombic force between the target compound and cavitation bubbles leads to higher degradation at acidic pH for most compounds. In addition, pH also changes free radical formation and reactivity in water during sonication, thereby altering degradation kinetics of target compounds. However, the influence of pH is not always consistent for various organic pollutants covering a broad range of physicochemical properties and reactivities. A systematic investigation on the pH effect is necessary to elucidate how pH alters cavitation bubble dynamics and collapse, radical yield and reactivity, distribution of target compounds in the vicinity of cavitation bubbles, water matrices transformation, and ultimately the degradation kinetics of organic pollutants. This first systematic review provides valuable insight into the pH effects on organic pollutant sonolysis, helps to improve our mechanistic understanding of the sonochemical system, and sheds light on future application of ultrasound in water engineering.     

条缝型空气幕对抽油烟机污染控制的辅助作用

运用数值模拟和实验测试方法,研究了住宅厨房在油烟机和送风气幕作用下的气流流动、温度分布和污染物扩散机理,并通过CFD数值计算对比分析了射速在0~5m/s范围的空气幕对厨房污染物扩散的影响.结果表明,单独使用抽油烟机作为厨房排风系统无法有效地将烹饪产生的油烟快速排向室外.空气幕作为补风装置应用在厨房通风系统不仅可以降低厨房空气温度,提高人体热舒适,而且能合理组织气流流动,降低厨房污染物浓度.然而,当油烟机排风量一定时,空气幕射速并非与油烟机捕集效率成正比,而是存在着最佳设计风速,排风速率为5m/s的最佳空气幕射速为0.6m/s.当通过增加油烟机排风量来提高捕集效率时,应根据不同的排风量确认对应的空气幕射速.     

中国近海和河口环境铜污染的状况

我国铜消费量已稳居世界前列,但随之而来的是铜带来的环境污染压力。铜污染问题不但在内陆环境逐渐突出,而且在近海和河口环境也日趋严重。通过分析近年来发表的我国近海河口海水、沉积物、牡蛎的铜含量数据,评估我国近海和河口环境的铜污染现状。数据显示,我国近海和河口环境大部分地区铜污染水平较低,但存在个别污染严重的区域。沉积物柱状样的数据显示,我国近海河口环境铜污染水平在过去几十年中呈逐渐上升趋势。铜污染已经开始威胁我国近海和河口环境的健康发展。"蓝牡蛎"和"绿牡蛎"是我国近海河口生物受铜污染影响的一个典型例子。多地发现"蓝牡蛎"的现象印证了铜污染源在近海河口环境普遍存在的观点。牡蛎受重金属污染而变色是一个值得研究的污染现象,它包含了复杂的生物学和生态学因素。本文探讨了"蓝牡蛎"和"绿牡蛎"形成的机制。     

Novel synthetic approaches and TWC catalytic performance of flower-like Pt/CeO2

A novel Ultrasonic Assisted Membrane Reduction （UAMR）-hydrothermal method was used to prepare flower-like Pt/CeO2 catalysts. The texture, physical/chemical properties, and reducibility of the flower-like Pt/CeO2 catalysts were characterized by X-Ray Diffraction （XRD）, Scanning Electron Microscope （SEM）, Transmission Electron Microscope （TEM）, N2 adsorption, and hydrogen temperature programmed reduction （HE-TPR） techniques. The catalytic performance of the catalysts for treating automobile emission was studied relative to samples prepared by the conventional wetness impregnation method. The Pt/CeO2 catalysts fabricated by this novel method showed high specific surface area and metal dispersion, excellent three-way catalytic activity, and good thermal stability. The strong interaction between the Pt nanoparticles and CeO2 improved the thermal stability. The Ce4＋ ions were incorporated into the surfactant chains and the Pt nanoparticles were stabilized through an exchange reaction of the surface hydroxyl groups. The SEM results demonstrated that the Pt/CeO2 catalysts had a typical three-dimensional （3D） hierarchical porous struc- ture, which was favorable for surface reaction and enhanced the exposure degree of the Pt nanoparticles. In brief, the flower-like Pt/CeO2 catalysts prepared by UAMR-hydrothermal method exhibited a higher Pt metal dispersion, smaller particle size, better three-way catalytic activity, and improved thermal stability versus conven- tional materials.     

双酚A对小鼠肝脏和肾脏细胞的氧化损伤

为探究双酚A(BPA)的氧化毒性,分别以剂量为20、40和80mg·kg~(-1)·d~(-1)的BPA对雄性昆明小鼠灌胃处理1周,并测定了小鼠体内活性氧自由基(ROS)水平、还原型谷胱甘肽(GSH)含量、丙二醛(MDA)含量和DNA-蛋白质交联系数(DPC)。与对照组相比,各BPA暴露组小鼠肝脏和肾脏细胞中的ROS生成量、MDA含量和DPC系数均升高,而GSH含量下降(P<0.05或P<0.01)。ROS生成量、GSH含量和DPC系数均显示出剂量-效应关系。研究表明,BPA可扰乱小鼠肝脏和肾脏细胞的氧化应激平衡,诱导细胞氧化损伤。     

Liquefaction of sawdust in hot compressed ethanol for the production of bio-oils

Direct liquefaction of lignocellulosic waste (sawdust) has been conducted in hot-compressed ethanol at temperatures from 150 to 250 °C. It was found that polyols such as glycerol, glycol and polyethylene glycol (PEG) promoted liquefaction process assisted with hot ethanol treatments seemed promising for production of bio-oils from lignocellulosic materials. Effects of different solvents and catalysts on liquefaction of sawdust were investigated. The results showed that the optimum operating condition for catalytic liquefaction is at 250 °C, 1 h of reaction time using glycerol and ethanol as solvent where operating at this condition realized the highest conversion of sawdust which is 97.8%. After reaction, the liquified product was separated by vacuum distillation. Two fractions were obtained, namely light oil and heavy oil. The properties and compositions of these two fractions were characterized in terms of Fourier transform infrared spectroscopy (FT-IR), gas chromatography–mass spectrometry (GC–MS), size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR).     

甘蔗渣纳晶纤维素酸法制备工艺的响应面法优化

为了获得甘蔗渣纳晶纤维素酸法制备的最佳工艺条件,基于Box-Behnken试验设计,选取硫酸质量分数、水解时间和水解温度为主要影响因素,采用响应面分析法优化了甘蔗渣纳晶纤维素酸水解制备工艺参数,并建立了二次多项式回归模型.方差分析表明,回归模型较好地反映了纳晶纤维素得率与硫酸质量分数、水解时间、水解温度的关系.甘蔗渣纳晶纤维素最佳的酸水解制备工艺条件为:硫酸质量分数56％,水解时间180 min,水解温度38℃.该条件下纳晶纤维素的得率达到52.93％.酸法制备工艺的响应面优化试验显著提高了甘蔗渣纳晶纤维素的得率,降低了纳晶纤维素的制备成本.     

乌鞘岭隧道施工环境保护措施探讨

对乌鞘岭隧道施工过程中的环境保护措施进行了探讨,对施工过程中产生的水污染、大气及洞内空气污染、固体废弃物污染、噪声污染、植被破坏等采取了相应的措施,取得了良好的效果。