Ag/ZnO hollow sphere composites: reusable photocatalyst for photocatalytic degradation of 17α-ethinylestradiol

Characterizations of Ag/ZnO hollow sphere by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectra, and UV–vis absorption spectra have been made after its synthesis. The results showed that the composite was hollow structure with diameters of about 1–4 μm. The samples synthesized were tested and identified as silver doped ZnO, which have extended and boosted the spectral absorption. The photocatalytic activity of Ag/ZnO hollow spheres was assessed using 17α-ethinylestradiol aqueous solution under UV irradiation. It has been observed that the 17α-ethinylestradiol absorption efficiency and degradation rate is higher for Ag/ZnO hollow spheres. As reusable photocatalysts, Ag/ZnO hollow spheres which could be easily separated from a suspension will facilitate their application in wastewater treatment with enhanced photostability.     

Direct N2O decomposition over La2NiO4-based perovskite-type oxides

Direct decomposition of N₂O by perovskite-structure catalysts including La₂NiO₄, LaSrNiO₄, and La_0.7Ce_0.3SrNiO₄ was investigated. The catalysts were prepared by the Pechini method and characterized by x-ray diffraction (XRD), BET, scanning electron microscopy (SEM), and O₂-TPD. Experimental results indicate that the properties of La₂NiO₄ are significantly improved by partially substituting La with Sr and Ce. N₂O decomposition efficiencies achieved with LaSrNiO₄ and La_0.7Ce_0.3SrNiO₄ are 44 and 36%, respectively, at 400ºC. As the temperature was increased to 600ºC, N₂O decomposition efficiency achieved with LaSrNiO₄ and La_0.7Ce_0.3SrNiO₄ reached 100% at an inlet N₂O concentration of 1,000 ppm, while the space velocity was fixed at 8,000 hr^?1. In addition, effects of various parameters including oxygen, water vapor, and space velocity were also explored. The results indicate that N₂O decomposition efficiencies achieved with LaSrNiO₄ and La_0.7Ce_0.3SrNiO₄ are not significantly affected as space velocity is increased from 8,000 to 20,000 hr^?1, while La_0.7Ce_0.3SrNiO₄ shows better tolerance for O₂ and H₂O_(g). On the other hand, N₂ yield with LaSrNiO₄ as catalyst can be significantly improved by doping Ce. At a gas hour space velocity of 8,000 hr^?1, and a temperature of 600ºC, high N₂O decomposition efficiency and N₂ yield were maintained throughout the durability test of 60 hr, indicating the long-term stability of La_0.7Ce_0.3SrNiO₄ for N₂O decomposition.

Implications:Nitrous oxide (N₂O) not only has a high global warming potential (GWP₁₀₀ = 310), but also potentially destroys ozone in the stratosphere. Pervoskite-type catalysts including La₂NiO₄, LaSrNiO₄, and La_0.7Ce_0.3SrNiO₄ are applied for direct N₂O decomposition. The results show that N₂O decomposition can be enhanced as Sr and Ce are doped into La₂NiO₄. At 600ºC, N₂O decomposition efficiencies achieved with LaSrNiO₄ and La_0.7Ce_0.3SrNiO₄ reach 100%, demonstrating high activity and good potential for direct N₂O decomposition. Effects of O₂ and H₂O_(g) contents on catalytic activities are also evaluated and discussed.     

锰矿区土-水界面污染流中重金属来源分析

基于对湘潭锰矿红旗矿区土-水界面重金属污染流的采样分析,通过相关性和主成分分析法,研究了锰矿区土-水界面重金属污染流中的锰、镍、铜、锌、镉、铅重金属的来源以及同源性。结果表明:6种重金属的差异性、离散程度、变异性较大;锰—镍、锰—锌、锰—镉、锰—铅、镍—锌、铜—锌、铜—铅、锌—镉、锌—铅、铅—镉呈极显著正相关,镍与锰以外的其他重金属相关性都较低;3个主成分的贡献率分别为58.300%、16.628%、11.115%,累积贡献率达到了81.543%,并且6种重金属在主成分1的载荷非常高。结合矿区的周边环境和自身特点,表明6种重金属的主要共同来源为矿区内的矿业活动,并且工业活动、交通运输、农业活动等也对矿区造成了一定程度的重金属污染。     

柴油机微粒中可溶性有机成分的真空干燥条件

柴油机碳烟颗粒(PM)中可溶性有机组分(SOF)含量是其重要的特性参数,而真空干燥法可方便、高效、可靠地分析颗粒SOF含量,对其干燥条件的探索具有重要的研究意义和应用价值。首先采用模拟的柴油机颗粒,分析不同的干燥条件对模拟SOF(柴油、润滑油)挥发率的影响规律,得出模拟的SOF分析的最佳干燥条件;在此基础上,探索了真实柴油机颗粒SOF分析的最佳干燥条件为:干燥温度220℃、干燥时间3 h、真空度98 kPa,得知SOF组分干燥的难易程度介于柴油和润滑油之间;同时,根据此干燥条件,分析了排气管末端采集的真实碳烟颗粒的SOF含量特性。     

城市化进程中失地农民的贫困问题及其治理

运用文献研究法和定性分析方法,借鉴社会学与人类学相关理论,探讨失地农民的贫困问题,总结失地农民贫困的类型,分析失地农民的贫困原因,并提出治理对策。结果发现:部分失地农民在城市中面临着贫困问题,经济贫困、文化贫困、能力贫困和权利贫困是主要贫困类型。导致失地农民贫困的因素主要有体制与制度设置不合理、城市社会的剥夺与排斥、城乡文化的冲突与非物质文化变迁滞后以及失地农民个人能力缺失等。治理失地农民贫困问题必须从宏观层面强化制度与政策的保障作用,从微观层面加强失地农民的自身能力建设。     

包容性增长中人的全面发展的评价

本文系统地阐述了理论界对人的发展评价指标体系的不同观点,并基于现有包容性增长观的理论基础,根据经济增长对人的包容的评价维度,综合考虑了人的经济发展环境、人的社会发展环境、人的生态环境、人口素质和人的生活质量五大要素来构建指标体系。通过上述5个方面30个指标,基于因子分析法建立人的全面发展综合评价模型,对我国2004-2009年的人的全面发展情况进行评价。研究结果表明:我国2004-2009年人的全面发展状况呈现逐年上升的趋势,且增幅也逐年递增,这表明随着人的全面发展的速度加快,人的全面发展状况越来越好。结合主成分分析解析获得人的全面发展的两个主因子,分别为外部因子(25个指标)与内部因子(5个指标),两个子因子的累积方差贡献率达到87.890%,其中外部因子的贡献率为76.202%,内部因子的贡献率为11.688%。这说明,在决定人的全面发展水平的诸多因素中,外部要素和内部要素是两大主要因素,且前者的影响力大于后者。分析外部因子与内部因子的年际变化规律可知外部要素是正面因素,起着积极的作用,而内部因素则不然。说明我国人的发展存在以外延发展为主,内涵发展不足的现象。综上,文章针对内涵发展不足提出政策建议,以期通过关注人的生活质量、发展潜能和幸福指数,最终来实现人的全面发展。     

江苏省农村居民点整理时序研究

近年来,农村居民点用地整理已经成为优化农村居民点布局和实现耕地占补平衡的有效途径,与此同时,其在城乡统筹发展和资源集约利用方面的作用也越来越显著,开展农村居民点用地整理已成为实现社会经济可持续发展的必然选择。以江苏省为例,从农村居民点用地整理迫切度、可行度两个方面共选取10个指标因子,构建了农村居民点用地整理时序研究的指标评价体系,并进行两维图论聚类的空间分析,以便对农村居民点整理时序作出安排,可为制定农村居民点整理规划以及确定、实施居民点整理项目提供决策依据。结果显示：江苏农村居民点整理时序得分区域分异明显,即从总体上看苏南优于苏中,苏中又优于苏北,从各县市分布来看,南京、常州、无锡等县市的整理时序优势较高,而泗洪、响水、灌云等县市的优势较低。同时,根据地域上的相似性,也形成了一些适宜进行规模整理开发的单元组合,如由高淳、溧水、溧阳等组成的地域单元。研究结论：结合指标评价和两维图论聚类分析进行的农村居民点整理时序安排和整理分区具有较强的指导意义     

Can the African food supply model learn from the Asian food supply model? Quantification with statistical methods

This study seeks to verify the relationship or correlation between food supply and four variables that are fertilizers, machinery, permanent cropland and permanent pasture land in Africa and Asia. The data were obtained from FAOSTATS and the World Resource Institute. The data were analyzed using the SPSS version 19. Pearson’s correlation statistical tool and the multiple linear regression methods were then used within the SPSS interface to analyze the data. The results show that the levels of fertilizer application and machinery use are more significant in affecting food supply in Asia than in Africa with respect to the four variables. In Africa, permanent cropland is of greater significance when food supply is concerned with respect to these four variables. The likely trend is for Africa to enact policies that will encourage investments in machines and organic fertilizers to be able to improve its food production and supply rather than merely increasing farm sizes.     

2011年中国大陆地震灾害损失述评

列出了2011年中国境内5.0级以上地震目录,总结了当年我国大陆地区各次地震灾害事件的基础数据信息和灾害信息,结合该年度我国大陆地区地震灾害事件发生所在省(自治区、直辖市)地震局的地震灾害评估资料,总结、归纳了2011年我国大陆地区地震灾害的主要数据和特性。最后,列出了1990年以来我国大陆地震灾害的相关数据,并进行了简单的比较。     

特大型城市客运交通碳排放与减排对策研究

本文基于对现有城市交通碳排放测算方法的比较分析,以上海市为例,采用IPCC"自下而上"法对特大型城市客运交通CO2排放进行了测算,结果显示:轨道交通是碳排放效率最高的客运方式,出租车最低;客运交通CO2排放总量增长迅速,且碳源结构发生了较大变化;近年客运交通CO2排放增量主要来自私人载客汽车,同时公务交通在客运交通碳排放中始终占较大比重。由此本文认为,控制客运交通碳排放的关键在于对以私人载客汽车和单位载客汽车为主的个体交通的管理和控制,形成以公共交通为主的交通结构。在此基础上,为了将控制碳排放纳入到城市交通政策目标中去,本文就主要城市交通政策对客运交通碳排放产生的影响进行了深入分析,并得出结论:以往的交通供给、需求管理政策对于抑制客运交通碳排放增长的作用有限;而就目前城市空间发展政策的实施效果而言,也不利于降低居民出行的碳排放水平。文章最后分别从交通供给、需求管理以及城市空间角度给出了控制客运交通碳排放的对策。