PIXE技术在分析汽车尾气颗粒物中的应用

介绍了利用PIXE分析技术对汽车尾气颗粒物的分析,获得了尾气颗粒物中的元素组成以及元素含量;同时对环境污染有影响的元素如S,Pb以及对影响污染物排放的元素如Si和Mn等进行了分析和讨论,研究表明,不同型号的汽车尾气颗粒物中,有害元素含量差异很大,虽然使用了汽油,但探测到有些尾气颗粒物中的铅含量还是相当高的,某些车型的汽车尾气中,Si,Mn含量相对偏高,此研究为治理汽车尾气污染提供依据。     

对固定污染源排气中颗粒物测定的新思考——以可凝结颗粒物为例

可凝结颗粒物是微细颗粒物,对环境的影响主要缘自其物理形态和化学组成。本文论述了可凝结颗粒物的定义和国内外颗粒物的测定方法。并就可凝结颗粒物的量级和危害进行了初步讨论,提出可凝结颗粒物是被忽略的固定源颗粒状污染物,揭示出中国现存颗粒物采样方法存在的问题,并对此问题进行研究。     

对固定污染源排气中颗粒物测定的思考——以可凝结颗粒物为例

可凝结颗粒物是微细颗粒物,对环境的影响主要缘自其物理形态和化学组成。本文论述了可凝结颗粒物的定义和国内外颗粒物的测定方法,并就可凝结颗粒物的量级和危害进行了初步讨论,提出可凝结颗粒物是被忽略的固定源颗粒状污染物,揭示出中国现存颗粒物采样方法存在的问题,并对此问题进行研究。     

洞庭湖“四水”的水动力条件对比分析

河流沉积物元素组成是源区岩石、风化作用、河流水动力分选等各种自然过程的结果.其中,水动力条件因控制沉积物的搬运形式、粒度特征、矿物组成等而对河流沉积物元素组成有极重要的控制作用.本研究对“四水”(即湘江、资江、沅江、澧水)入湖河床沉积物的矿物组成、元素富集特征进行分析,并选取合适的特征元素计算水动力分选指数(WI)来反演“四水”河流水动力条件.结果显示,Al₂O₃、TiO₂、Zr等元素是指示沉积物水动力条件的主要特征元素,“四水”的河流水动力条件为澧水>沅江>湘江>资江,WI(Zr/Al₂O₃)为本研究中描述“四水”水动力条件的最适宜指标.     

于桥水库水源地水体重金属潜在生态风险评价

针对于桥水库水源地河流中重金属可能存在的生态风险,以于桥水库水源地河流33个子流域采样点重金属的监测数据为基础,对河流悬浮颗粒物和表层沉积物中Cd、As、Pb、Cu、Cr和Zn等重金属的含量进行分析,并采用Hakanson潜在生态风险指数评价了河流表层沉积物中以上重金属污染的状况和潜在生态风险.结果表明:河流悬浮颗粒物中Cd和As的平均含量超过我国土壤环境质量一级标准值3倍,Cu和Cr的平均含量是土壤环境质量一级标准值的1.6倍,Pb和Zn的平均含量低于土壤环境质量一级标准,Cd和Cr显示出一定的生态风险;表层沉积物中Cu、As和Cr的平均含量和部分表层沉积物样品中Pr、Cd和Zn的平均含量超过我国土壤环境质量一级标准值;比较3条支流河流可知,Cd、As和Pb在沙河沉积物中含量最高,在黎河沉积物中含量最低;Cr和Zn在沙河沉积物中含量最高,在淋河沉积物中含量最低;Cu在淋河沉积物中含量最高,在黎河沉积物中含量最低. Hakanson潜在生态风险评价结果显示,水体悬浮颗粒物中As和Cd分别属于极强和较强生态风险等级,河流表层沉积物中Cd为中等潜在生态风险级别,重金属总体属于中等风险级别.     

西南喀斯特地区河流水化学研究综述与展望

喀斯特地区生态环境脆弱,河流水体溶解离子及其运移规律独特,作为世界三大喀斯特集中分布区之一的中国西南喀斯特地区,其河流水化学研究对区域河流环境乃至水环境保护有重要意义。从河流水体中主要离子组成角度出发,综述了中国西南喀斯特地区河流水化学研究现状和进展,归纳了喀斯特地区河流水化学时空特征及其影响因素。总结了喀斯特地区河流水化学特征及其影响规律,指出目前研究存在的问题、研究热点、难点及突破点。     

龙岩市大气中PM10的微观形貌特征及组成分析

选择福建省龙岩市环境监测站的大气常规监测点位为采样点, 于2009年9月16日至9月23日进行24 h连续采样, 采用扫描电镜方法分析样品中PM₁₀的微观形貌特征和元素组成, 通过与当地典型污染源颗粒物的微观形貌和特征元素进行对比, 确定其主要污染来源. 研究结果表明: 各类污染源的微观形貌及特征元素均有明显区别,  不同采样点样品中PM₁₀的微观形貌特征及元素组成也有差异, 据此分析得出的大气PM₁₀颗粒物来源与化学质量平衡受体模型(CMB8.2)源解析结果一致.     

厦门市大气颗粒物化学元素特征

无机化学元素是大气颗粒物的主要化学构成成分。Al、Si、Ca、Fe、Zn和K等化学元素为大气可吸入颗粒物PM10中的主要地壳元素成分．重金属元素As、Cd、Sb、Pb和Hg等尽管浓度较低，但其毒性较大，容易富集在细颗粒物表面．且能长时间停留在空气中，对人体及生物体会产生危害．     

大气颗粒物浓度与重金属元素分析研究进展

 综述了大气颗粒物浓度与重金属元素分析方面的研究进展,阐述了大气颗粒物的界定、来源和组成、途径和危害、检测仪器和方法、相关技术标准等,比较了国内外相关标准、检测仪器等的发展情况,指出中国在法律法规、监测标准、测量仪器开发等方面仍存在一定差距,开发自动、在线、连续监测大气颗粒物的浓度及所含重金属元素的种类、含量等一体化仪器是检测仪器的发展方向.     

中国大气颗粒物污染与致癌研究进展

 室外空气污染和污染空气中的颗粒物是一类致癌物，而近年中国的大气颗粒物污染仍然维持在较高浓度水平。通过综述中国近年大气颗粒物污染现状和开展的颗粒物致癌机制研究，分析中国研究中颗粒物有关实验动物致癌性的证据和颗粒物致癌的人群流行病学线索，阐述大气颗粒物与癌症的关系，提出中国亟需开展相关研究。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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