CuO-ZnO催化剂的XRD和EXAFS研究

用XRD和EXAFS方法研究了CuO-ZnO(50:50)CO_2加氢合成甲醇催化剂的结构.XRD研究发现,在催化剂还原前后,分别存在CuO,ZnO和Cu-ZnO晶相.EXAFS研究发现,在CuO-ZnO中,Cu—O,Cu—Cu键长及Cu的氧配位数、Cu的Cu配位数与纯CuO的十分接近,在Cu-ZnO中,Cu—Wu键长、Cu的Cu配位数与纯Cu的十分接近,说明催化剂在还原前后,CU的近邻结构分别与CuO与Cu的十分接近.纯Cu的活性、选择性很低,而Cu-ZnO的活性、选择性较纯Cu的有很大提高,说明催化剂的性能与催化剂中Cu的近邻结构无关.     

型煤燃烧固硫的钠离子效应

本文用脉冲二氧化硫荧光分析仪连续测试了煤样中二氧化硫的浓度，并用Ｘ荧光、Ｘ衍射和电子扫描电镜等方法，分析了添加钠离子样品的含硫率、物相及表面形貌。实验结果表明，钠离子添加剂改变了二氧化硫释放过程，抑制了硫酸钙的分解。灰样成分中既有稳定的三元化合物３ＣａＯ．３Ａｌ２Ｏ３．ＣａＳＯ４，也有不稳定的化合物硫酸钙存在，说明钠离子添加剂对提高固硫率有促进作用。     

应用在线传感器实现前置反硝化工艺生物脱氮的过程控制

为了实现前置反硝化工艺硝化反硝化反应的过程控制,系统地研究了硝化反硝化过程中DO、pH和ORP的变化规律,并考察了它们作为硝化反硝化过程控制参数的可行性.结果表明,pH值在缺氧区的变化分为下降型和上升型,从而指示系统反硝化反应进行的程度以及内循环回流量是否充足;缺氧区末端ORP值和硝酸氮浓度具有较好的相关性;好氧区第1格室的DO浓度可以指示进水氨氮负荷高低;pH值在好氧区的变化也可分为下降型和上升型,可指示系统硝化反应进行的程度、曝气量和碱度是否充足;好氧区末端ORP值与出水氨氮、硝酸氮浓度具有很好的相关性.在此基础上建立了硝化反硝化反应在线控制系统,从而实现曝气量、内循环回流量和外碳源投加量的在线控制,提高系统出水水质、降低运行费用.图7表1参8     

Relationship between sludge settleability and membrane fouling in a membrane bioreactor

The evolution of activated sludge settleability and its relationship to membrane fouling in a submerged membrane bioreactor were studied at a lab-scale equipment fed with synthetic wastewater. It was found that sludge volume index (SVI) gradually increased and the sludge settleability was reduced, which was caused by the propagation of filamentous bacteria. With increasing SVI, the average increasing rate of trans-membrane pressure increased, the stable filtration period was shortened, and the two stages (smooth stage and accelerating stage) of the trans-membrane pressure were more obvious. At the same time, the increasing rate of trans-membrane pressure at the smooth stage decreased and the rate at the accelerating stage increased with SVI, respectively. The observation by using scanning electronic microscopes showed the cake layer with loose structure and large thickness formed on the membrane surface due to the appearance of filamentous bacteria and high SVI in sludge. Influence of the sludge settleability on the trans-membrane pressure was related to the structure and thickness of the cake layer on the membrane.     

钙化合物对前生体生成二英类的阻滞作用

针对城市生活垃圾焚烧（MSWI）过程中二（口恶）英类的生成机制以及焚烧飞灰的组成,研究了MSWI飞灰中常见的钙化合物（CaO,Ca（OH）2,CaCl2,CaSO4及Ca（NO3）2）对前生体五氯酚（PCP）及六氯苯（HCB）生成二（口恶）英类的阻滞作用.结果表明,280℃下加热2 h,Ca（NO3）2,Ca（OH）2和CaO对PCP生成二（口恶）英类的总阻滞效率分别为93.7%,80.4%和98.9%,而CaCl2和CaSO4几乎没有效果.CaO对PCP和HCB混合物生成二（口恶）英类物质同样具有良好的阻滞效果.另外,探讨了上述钙化合物对PCP及HCB生成二（口恶）英类的阻滞作用机理.     

Bayesian analysis under ordered functions of parameters

Ordered parameter problems arise in a wide variety of real world situations and are dealt with extensively in the literature. Traditional frequentist methods for dealing with these problems are rather complicated theoretically, especially when sample sizes are small. Bayesian methods are not widely used because high dimensional numerical integration is often required. However, Markov chain Monte Carlo methods provide alternatives to such numerical integration and also deal with ordered parameter problems in a straightforward manner. Little is known about the situation where functions of parameters are ordered. Such problems may seem to be of little practical concern initially, but one can readily see their importance in situations where ordering is placed on the means and variances of several normal or Gamma populations. For the Gamma distribution we will present real examples where we will analyze monthly precipitation data from San Francisco, California and Oakland Mills, Iowa. For the San Francisco data we will simultaneously order both monthly precipitation means and variances. For the Iowa data we will place ordering on seasonal average while still estimating monthly means. Our results show that we would obtain sharper, more accurate inference when order restrictions are employed.     

岳阳市城市绿化树种的选择及配置模式研究

选择观赏价值高、抗逆性强、保健功能强、经济效益高同时具有丰富历史文化底蕴和地方特色的植物材料用于城市林业建设中,可显著提高城市园林绿化的科技含量和综合效益;在园林植物配置上,根据园林美学原则和功能性要求,进行混植、群植、丛植、对植和孤植等,在充分发挥树木的群体美和个体美的同时可显著提高配置模式的整体功能性．     

海洋酸化与重金属、有机污染物和人工纳米颗粒的联合毒性效应研究进展

由于大量人类活动的影响,大气CO_2浓度持续增加,其中约1/3被海洋吸收,导致表层海水pH值降低和碳酸盐平衡体系波动,即"海洋酸化"现象。污染物的海洋环境效应一直是全球环境科学领域研究的热点。在实际环境中,海洋酸化往往与污染物共同存在并作用于海洋生态系统,且海洋酸化极有可能改变污染物的海洋环境行为从而影响其毒性效应。但现有研究大多针对海洋酸化或者污染物单独作用下的毒性效应展开,对海洋酸化与污染物的联合毒性效应的研究不足、亟待加强。为此,综述了近年来海洋酸化与典型污染物(重金属、有机污染物)及新型污染物(人工纳米颗粒)的相关文献,重点阐述了海洋酸化对污染物环境行为的影响和海洋酸化与污染物对海洋生物的联合毒性效应,指出当前的研究不足,并对未来的研究方向进行了展望。     

绿色食品产地土壤中PAHs测定方法研究

对绿色食品产地土壤中多环芳烃的气相色谱质谱联用分析法进行了研究。样品经索氏提取后硅胶氧化铝复合柱净化,最后用GC/MS内标法进行定性定量分析。方法相关系数除苯并(a,h)蒽的相关系数R2=0.9970外,其余目标化合物的相关系数R2均大于0.9991,各化合物线性关系良好。方法加标回收率大多在70%至90%间,各目标化合物的方法检测限为2.2～40ng/kg。     

地统计学在土壤重金属研究中的应用及展望

从采矿学与地质学研究中发展起来的地统计学是应用数理统计学的一个分支。与传统的统计学相比，地统计学可应用于土壤重金属研究中，能探索土壤重金属的空间分布特征及其变异规律。地统计学的基础理论与方法主要包括：区域化变量、半方差函数、克立格空间插值技术。半方差函数可以用来描述研究土壤重金属分布的空间相关性；而克立格插值可以对未采样区土壤重金属的含量进行无偏最优估计。在对地统计学理论进行简要阐述的基础上，回顾了近些年在土壤重金属研究的采样设计、空间结构分析、空间插值等方面的应用，并就其应用前景作了展望。