西安市长乐公园土壤重金属含量的测定及污染评价

用HNO3-HF-HClO4联合消煮法处理西安市长乐公园土壤样品,根据测定其中Pb,Zn,Cu,Cr,Cd等重金属的含量,得出其平均值均高于中国土壤环境背景值.相关性分析显示,Pb,Zn,Cu 3种元素之间具有较高的相关性.用单因子指数法、内梅罗污染指数法评价了西安市长乐公园土壤重金属污染程度,得出公园土壤中5种重金属处于中等污染水平.     

粤北某矿区地表土壤重金属污染的分布研究

为了查清粤北某大型铅锌矿区周边地表土壤重金属的污染情况,对该地的冶炼、采矿和选矿区周边三处地表土壤,13个样点和39个样品中的Pb、Zn、Cu、Cd 4种主要重金属的分布进行了系统的检测与分析.结果表明:冶炼厂周边主要是Pb、Cd两种重金属超标,分别为国家土壤环境质量二级标准的1.72和15.3倍;采矿区周边重金属污染较严重,Pb、Cu、Cd 3种重金属依次为国家土壤环境质量二级标准的3.90、1.17和17.17倍;而选矿区周边农田的土壤重金属含量均在国家土壤环境质量二级标准内.     

碳酸盐岩地区不同种植方式下黄壤重金属含量特征及评价

以贵州开阳县不同种植方式下的黄壤为供试样品,对其重金属含量特征及污染水平进行探究。结果表明:不同种植方式下,单作土壤在种植前和收获后为酸性,而连作和间作在两个时期为中性;土壤重金属Cd、Cr、Cu、Zn和Pb的含量变化规律基本一致,均呈现种植前高于收获后;土壤pH与土壤重金属Cd、Cr、Cu、Zn的变异程度均不大,而Pb在连作种植前与间作收获后的变异程度较大;相关性分析显示,Cd与Cu、Pb之间、Cu和Zn、Pb之间均具有较高的同源性;综合污染指数(P_综)表现为单作(种植前)间作(收获后)连作(种植前)单作(收获后)间作(种植前)连作(收获后),分别为14.20、13.67、13.62、11.38、9.89和8.04,均高于3.0,属于重度污染等级,土壤受污染相当严重,其中单作和连作在收获后污染程度较种植前有不同程度的下降,而间作则呈上升趋势。在所选定的污染评价因子中,Cd的贡献率极高,为土壤污染的主要影响因子,其次是Cr.     

秦岭铅锌矿冶炼厂区周边土壤重金属分布特征研究

目的为了解铅锌过程中重金属对周边土壤的污染情况。方法对秦岭凤县铅锌矿冶炼厂周边8个区域土壤中Zn、Pb、Cd、Cu等4种主要重金属的分布规律进行了初步研究,分析了冶炼厂周边环境现状,提出了对策建议。结果研究表明冶炼厂周边土壤重金属污染严重,绝大部分区域重金属含量已超过对照点测定值和国家土壤环境质量二级标准,最高超标倍数依次为Zn10倍、Pb6．5倍、Cd6．2倍、Cu4．0倍。结论厂区常年主导下风向土壤中重金属含量高于上风向土壤中;冶炼厂周边土壤环境中重金属污染以Zn为主,其次为Pb和Cd,Cu污染较小。     

内蒙古不同产地甘草和土壤中重金属含量与评价

为研究内蒙古道地甘草产地土壤和甘草根重金属的含量特征和污染状况,选取鄂尔多斯杭锦旗、赤峰翁牛特旗和锡林郭勒盟正蓝旗三个产地,采集两个土层土壤(0—20cm,20—40cm),对重金属As、Hg、Cd、Pb和Cu的含量及相关性进行了分析.结果表明:三个产地土壤中As、Hg、Cd、Pb和Cu的含量均显著低于国家土壤环境质量一级标准;除鄂尔多斯土壤重金属As,赤峰土壤重金属As和Cu以及锡林郭勒盟土壤重金属Cd、Pb和Cu的含量高于内蒙古土壤背景值外,其他指标均显著低于内蒙古土壤背景值.用单项污染指数法、内梅罗综合污染指数法和潜在生态评价指数法评价产地土壤重金属的污染状况,结果表明三个产地土壤都是清洁的.土壤中As、Hg和Cu相互之间,均呈极显著负相关,可能这三种重金属之间存在着一种平衡和制约的关系;甘草根中As、Cd和Pb相互之间均呈极显著正相关;而土壤中重金属Pb与甘草根中重金属As、Cd和Pb呈极显著正相关,这也许能够为预防甘草重金属超标提供依据.另外,产地所采甘草根中五种重金属含量均显著低于药用植物及制剂外经贸绿色行业标准.     

雪鸡坪-春都铜矿区土壤重金属污染评价

以香格里拉县雪鸡坪-春都铜矿区土壤为研究对象,分析长期采矿活动对表层土壤重金属含量的影响.通过对矿区土壤的重金属(Cd,Hg,As,Cu,Cr,Zn,Pb)含量进行测定,以国家土壤环境质量3级标准和云南省土壤背景值为评价标准,采用内梅罗综合指数法分析矿区土壤的重金属污染现状,运用Hakanson潜在生态危害指数法进行潜在生态风险评估.结果表明:矿区长期开采活动导致Hg,As,Pb,Zn,Cu这5种重金属含量高于云南省土壤背景值,Hg,As,Pb,Zn,Cu,Cd这6种重金属含量高于全国土壤背景值;Cu的单因子污染指数值最高,污染水平超标,为该矿区土壤的主要污染元素;综合土壤环境指数为1.14,土壤受到轻度污染;矿区Hg元素具有强的生态危害,Cu元素具有中等生态危害,其余元素为轻微生态危害,综合生态危害指数为226.22,整体上该矿区的生态风险属于中等水平.     

基于标准化方法的峰峰煤矿塌陷区农田表层土壤重金属污染评价研究

为进一步评估煤矿塌陷对农田土壤环境的影响,文章系统采集测试了煤矿塌陷区农田表层土壤39件,运用标准化方法对重金属元素As、Cd、Cr、Cu、Hg、Ni、Pb和Zn进行了污染评价研究。结果表明峰峰煤炭塌陷区农田表层土壤重金属元素均值均高于全国土壤环境背景均值。表层土壤重金属元素污染组合特征为:元素Pb、Cr、As和Ni为一族;元素Hg、Cd、Zn、Cu为一族。表层土壤明显受到了重金属元素Cd、Cu、Hg、Pb和Zn的污染。重金属元素Hg的污染程度以轻度为主,中度为辅;重金属元素As、Cd、Cu和Zn为点状轻度污染。     

黄河三角洲农田土壤-作物系统重金属污染风险评估

重金属严重影响着农业用地土壤环境质量以及农产品安全,已引起国内外广泛关注. 本研究以我国重要的粮 食产区黄河三角洲典型农田为对象,评估了农田土壤-作物系统中重金属的污染风险. 研究结果表明,黄河三角洲农田 土壤中重金属 Cr、Cu和 Pb的质量分数具有显著性差异(P<0.05), Cr的质量分数(47.20mg·kg-1)最高, Cu(26.00 mg·kg-1)次之,而 Pb(13.90mg·kg-1)最低,各重金属分布存在中等的空间异质性. 根据单因子污染指数和内梅罗综合 污染指数,黄河三角洲农田土壤总体上处于清洁水平,重金属污染风险较低,但不同作物区具有显著性差异(P<0.05). 小麦田和水稻田土壤 Cr、Cu的质量分数显著高于藕池和玉米田,小麦田和水稻田土壤 Pb的质量分数与藕池差异不显 著,但显著高于玉米田.3种重金属元素在各主要农作物的地上部分均呈现一定程度的富集,且 Cu的富集程度最高,Pb 的富集程度最低;不同作物对重金属元素的富集程度不同,对 Cr的富集程度由高到低呈现为玉米、藕叶、水稻、小麦,对 Cu的富集程度由高到低呈现为玉米、水稻、藕叶、小麦,而对 Pb的富集程度由高到低呈现为水稻、玉米、小麦、藕叶.      

草海湖底沉积物重金属垂直分布特征及污染状况评价

选取贵州省威宁县草海湖底沉积物为研究对象,对Pb、Cr、Zn、Cu、As 5种重金属的含量进行测定。采用单因子指数法和潜在生态风险指数法对各重金属污染状况进行分析评价,定量确定了草海湖底沉积物中主要的污染因子和潜在生态风险程度。结果表明:5种重金属中,Zn和Pb的含量均高于中国土壤环境背景值和贵州省土壤环境背景值,其中Zn含量最大,其次是Pb、Cr、Cu、As;各重金属在不同深度上有不同的变化规律;草海湖主要的重金属污染因子为Zn、Pb,湖底沉积物重金属的综合污染指数为8. 88,属于中度污染,潜在生态危害程度低。     

陈腐垃圾的重金属污染特征及其潜在风险评价

以九江市生活垃圾填埋场陈腐垃圾为调查对象,分析了不同填埋结构不同回灌方式下陈腐垃圾中Cr、Cu、Zn、As、Cd、Hg和Pb的含量.结果表明:4个填埋体陈腐垃圾中Cr、Cu、Zn、As、Cd、Hg和Pb重金属平均含量均低于《土壤环境质量标准》(GB 15618-1995)三级标准,厌氧填埋体D(渗滤液回灌)陈腐垃圾中的Cr略微超标,2种填埋结构清水回灌方式陈腐垃圾中重金属的含量低于渗滤液回灌方式;准好氧填埋结构陈腐垃圾内梅罗综合污染指数处于清洁水平,厌氧填埋结构陈腐垃圾内梅罗综合污染指数处于轻微污染水平.潜在生态风险评价表明,不同填埋结构、不同回灌方式垃圾填埋场陈腐垃圾的重金属潜在生态风险指数(RI)均处于轻微生态风险水平,没有明显的级别差异.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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