Catalytic decomposition of polychlorinated biphenyls (PCBs)

In this study, polychlorinated biphenyls (PCBs) were decomposed by low‐temperature heat treatment with metallic catalyst, and with metallic catalyst and a hydrogen source. Of the catalysts used, iron (Fe) was the most active catalyst for the decomposition of PCBs, and the decomposition was due to dechlorination. The addition of hydrogen sources accelerated the decomposition of PCBs in the presence of catalyst. Surface analysis of the catalyst using X‐ray photoelectron spectroscopy (XPS) suggested that the emitted chlorine was presumed to form metal chloride. The reactions of each homolog can be expressed by a successive first‐order reaction model. This means that a substituted chlorine is successively detached during this reaction. The overall decomposition rate in this reaction system was controlled by that of the lower chlorinated homologs. The decomposition rates with Fe and NaBH₄ for the lower chlorinated homologs were about 10 times as fast as the rates with only Fe.     

平面问题中主应变测量不确定度评定

目的实现平面场中主应变的测量不确定度评定。方法首先建立主应变的是非线性传播测量模型,然后应用基于二阶TAYLOR级数展开理论的不确定度传播方法(LPU方法),开展平面问题中主应变的测量不确定度评定。针对二种常用的应变花,建立以主应变为输出量、以应变花之三个方向测量应变为输入量的测量模型,并将二阶LPU方法应用于该模型。设计数值计算算例,以说明主应变不确定度的评定过程和方法,并与一阶LPU结果进行了比较。结果当应变花三个方向的应变测量结果相近时,文中方法与一阶LPU方法获得的主应变的不确定度评定结果存在明显的差异,主应变不确定度评定结果在数值上都大于应变花测量的不确定度。当应变花三个方向的应变测量结果相差较大时,文中方法和一阶LPU方法获得的主应变测量不确定度评定结果相差不大。结论特定情况下,主应变的测量不确定度值远大于应变花测量的不确定度,且与一阶LPU方法的评定结果有显著差异,二者可相差一倍。     

Simultaneous removal of NO and SO2 from dry gas stream using non-thermal plasma

In order to investigate the feasibility of sequential removal NO and SO_2 using non-thermal plasma and adsorbent simultaneously,the removal of NO and SO_2 from dry gas stream(NO/SO_2/N_2/O_2)with very little O_2 using non-thermal plasma was investigated using a coaxial dielectric barrier discharge.Comparative experiments were carried out in the dry gas stream with and without Ar respectively at O_2 concentration of 0.1%.The results showed that NO could be removed remarkably and it would be enhanced in the presence of Ar in the dry gas stream.It seems that SO_2 could not be removed unless there is Ar in the dry gas stream.The mechanism of removal of NO and SO_2 in the dry gas stream was discussed.     

香溪河附石性大型底栖动物功能摄食类群研究

利用1∶50 000地形图对香溪河进行划分,显示香溪河为一条6级河流。分析包括捕食者(PR)、撕食者(SH)、刮食者(SC)、直接收集者（GC）和过滤收集者(FC)在内的5个主要功能摄食类群的组成,发现香溪河主要摄食类群以直接收集者和刮食者为主。各功能摄食类群的密度和生物量随着河流级别的变化而发生变化,基本趋势为：直接收集者和滤食者的密度和生物量都随着河流级别的增加而增大;撕食者和刮食者的密度和生物量的密度随着河流级别的增加而减小;而捕食者在整个流域内的密度上游小于下游,生物量却是上游大于下游。研究结果表明香溪河在夏季其上游物质来源以附石性藻类生产为主,下游则以异源性细有机颗粒输入为主。此外,功能摄食类群的密度与部分环境因子具有显著的相关性：过滤收集者与Ca2+和河宽相关,收集者与SiO2相关显著,刮食者与海拔和氨氮相关性较高,撕食者与电导和PO4 P相关性较高.     

Effect of Co(Ⅱ) dopant on the removal of Methylene Blue by a dense copper terephthalate

In this research, for the first time, a series of Co(Ⅱ) doped copper terephthalate(Co X-Cu BDC,where X is doping percentage) were successfully synthesized via solvothermal method and were tested for dye removal application. The physical properties of Co X-CuBDC were studied by several techniques including X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM), energy-dispersive spectroscopy(EDS), thermogravimetric analysis(TGA)and Brunauer–Emmett–Teller(BET) surface area analysis. The incorporation of Co(Ⅱ) dopant leads to isomorphic substitution of Cu(II) in the CuBDC framework with the maximum doping percentage of 22. Doping and parent MOFs which are non-porous were used for removal of Methylene Blue(MB) from aqueous solution. Adsorption capacity of Co22-CuBDC and CuBDC are 52 and 58 mg/g, respectively, both of which are higher than the adsorption capacity recorded from several high porosity MOFs. Adsorption kinetic studies indicate that adsorption process follows pseudo-second order model while the adsorption mechanism is dominated by electrostatic attraction. Overall, even though these materials show non-porous characteristic,it can be used effectively in wastewater treatment application.     

CO2 adsorption using TiO2 composite polymeric membranes: A kinetic study

CO₂ is the main greenhouse gas which causes global climatic changes on larger scale. Many techniques have been utilised to capture CO₂. Membrane gas separation is a fast growing CO₂ capture technique, particularly gas separation by composite membranes. The separation of CO₂ by a membrane is not just a process to physically sieve out of CO₂ through the controlled membrane pore size. It mainly depends upon diffusion and solubility of gases, particularly for composite dense membranes. The blended components in composite membranes have a high capability to adsorb CO₂. The adsorption kinetics of the gases may directly affect diffusion and solubility. In this study, we have investigated the adsorption behaviour of CO₂ in pure and composite membranes to explore the complete understanding of diffusion and solubility of CO₂ through membranes. Pure cellulose acetate (CA) and cellulose acetate-titania nanoparticle (CA-TiO₂) composite membranes were fabricated and characterised using SEM and FTIR analysis. The results indicated that the blended CA-TiO₂ membrane adsorbed more quantity of CO₂ gas as compared to pure CA membrane. The high CO₂ adsorption capacity may enhance the diffusion and solubility of CO₂ in the CA-TiO₂ composite membrane, which results in a better CO₂ separation. The experimental data was modelled by Pseudo first-order, pseudo second order and intra particle diffusion models. According to correlation factor R², the Pseudo second order model was fitted well with experimental data. The intra particle diffusion model revealed that adsorption in dense membranes was not solely consisting of intra particle diffusion.     

不同灾后救援情境下医疗人员与医疗物品最优订购的报童模型

灾后救援过程中医疗人员和医疗物品的最优配置（订购）是应急管理的1个重要问题,运用多产品报童模型分析不同灾后救援情境下医疗人员与医疗物品最优配置（订购）问题。首先,针对地震、海啸等不同灾害类型的灾后救援情境,结合医疗人员和医疗物品的互补特征,提出3条基本假设;其次,分析医疗人员和医疗物品2种资源不同订购量的期望收益函数,构建2种资源的最优订购报童模型,根据海瑟矩阵证明该问题存在着最优解,并运用库恩塔克优化条件得出最优解;最后,结合数值分析方法,分析地震、海啸等救援情境下医疗人员与医疗物品的最优订购数量。研究结果表明:医疗物品最优订购数量与其成本成反比;医疗物品最优订购数量与医疗人员最优配置数量成正比,与其退货补贴成正比;医疗人员和医疗物品的最优配置（订购）数量需要满足基本的互补关系。     

地下水中石英砂滤层去除氨氮的动力学方程和基于反应活化能的分析

在中试条件下考察了成熟石英砂表面滤膜去除地下水中氨氮(NH_4~+-N)的效果,并通过改变不同的进水NH_4~+-N浓度(1.6、2.1、2.5mg·L~(-1))拟合NH_4~+-N反应动力学方程.结果表明,NH_4~+-N在滤层中的去除符合一级动力学方程;当进水流速为5 m·h~(-1)时,滤层厚度为130 cm的成熟石英砂滤层最大NH_4~+-N去除浓度为2.51 mg·L~(-1).同时,通过改变不同的进水温度(10.8、10.9、12.4、14.0℃)测试了NH_4~+-N反应活化能,结果表明,NH_4~+-N在成熟石英砂滤层中氧化所需的活化能为96.8 k J·mol~(-1).     

论行政机关提起的生态环境损害赔偿之法律范畴与路径

行政机关提起的生态环境损害赔偿之法律范畴与路径是生态环境损害赔偿立法时需要解决的两个核心问题。我国目前将生态环境损害赔偿定位为民事范畴,该定位一定程度上违背了行政责任与民事责任的界分。本文从生态环境的属性切入,得出在公私法二分语境下,生态环境损害赔偿宜纳入行政法范畴的结论;其次,通过对比美国与欧盟的做法,展开行政法视角下强制性与非强制性二元路径的探讨。本文认为,我国可借鉴美国的做法,在未来立法时采用二元路径:违法排放污染物质需要清除的,行政机关可依法责令清除污染,或采用执法和解方式与责任人达成一致;生态环境服务功能损失的恢复则不宜采用强制性命令,行政机关可与责任人进行和解。