中山市不同区域农田土壤汞分布特征与污染评价

本文以中山市东部、北部、南部和中部农田土壤中的汞为研究对象,共采集139个土壤样品,经王水消解后用原子荧光光谱仪分析样品的汞含量水平.结果表明土壤汞含量范围为0.004~0.515 mg·kg~(-1),平均值为0.120 mg·kg~(-1),四个区域汞含量大小依次为中部东部南部北部.根据单项污染指数判断,中部土壤受汞污染较多,超标率相对较大.地质累积指数法也显示中部区域受人为活动影响大,汞污染程度大于其他三个区域.两种评价方法均显示中山大部分农田土壤为未污染状态,只有少数为轻度或中度污染.人类活动是导致中山土壤汞污染的主要因素,应密切关注和采取改善措施.     

南方典型稻田土壤-水稻系统环境质量评价

为研究南方典型区域稻田土壤—水稻系统中重金属含量,系统采集了江西省进贤县、金溪县、渝水区、高安市、安福县和兴国县等6个水稻主产区典型田块土壤、水稻和灌溉水,重点分析了土壤和水稻铅、镉、砷和汞含量及其土壤养分,并采用单因子污染指数和内梅罗综合指数对土壤—水稻系统中重金属含量进行评价。结果表明,研究区稻田土壤pH、有机质、总氮、总磷、总钾、碱解氮、有效磷和速效钾总均值分别为5.48、32.99 g/kg、2.06 g/kg、0.54 g/kg、16.04 g/kg、156.71 mg/kg、14.00 mg/kg和94.98 mg/kg。研究区土壤铅、镉、砷和汞含量总均值分别为35.46、0.18、7.21和0.17 mg/kg,单因子污染指数均小于1,内梅罗综合污染指数为0.56,土壤环境质量等级为清洁;但渝水土壤镉含量为0.37 mg/kg,超过限量标准(0.30 mg/kg),土壤环境质量属于警戒状态。研究区糙米铅、镉、砷和汞的含量总均值分别为0.06、0.17、0.24和0.0086 mg/kg,单因子污染指数均小于1,内梅罗综合污染指数均值为0.77,糙米环境质量等级为警戒限;但兴国和渝水糙米镉含量分别为0.22和0.35mg/kg,均超过限量标准(0.20 mg/kg),环境质量等级分别为警戒限和轻度污染。相关性表明,糙米镉与土壤镉和铅呈显著正相关,而与土壤砷呈显著负相关;糙米砷与土壤砷和有效磷呈显著正相关。总之,重金属镉是调查区域水稻安全性最主要的潜在污染元素,需重点关注兴国和渝水两地水稻食品安全。     

漳州市近郊表土壤总汞空间分布特征及与城市化关系探讨

针对25个采自漳州市近郊自然土壤的表层样品进行了细致汞总量检测,依据市国土部门提供的空间图形数据构建环境信息系统,利用GIS的相关功能进行分析成图.结果表明,研究区内总汞含量分布不均,空间变化大.近郊表土中总汞含量在0.203-1.265 mg·kg-1范围内,平均为0.64mg·kg-1高于福建土壤背景值.以2003与2007年二个时间断面观察,漳州市城市化主要为其东部区、西部为差异性扩张.扩张迅速区虽然不是总汞含量最高值区,但同未扩张区比较却明显偏高.全区中的总汞高值区与重工业区有一定程度的对应关系.     

庐江矾矿区土壤理化特性研究

为深入了解矿区废弃地土壤理化特性,探究其复垦困难的关键因素,以庐江矾矿为研究对象,对土壤理化性质进行测定。结果显示:矿区土壤为砂质壤土;含水量为12.09%,干旱等级为轻旱;土壤容重为1.39 g·cm~(-3);p H为4.20;有机质含量为0.59%,全氮为0.037%,有效磷和速效钾分别为7.66 mg·kg~(-1),55.06 mg·kg~(-1)。这表明矿区砂化明显,具有轻度干旱现象,土壤呈酸性、结构性差,有机质、全氮缺失严重,氮磷钾比例失调,养分极低。土壤理化性质之间相关性分析表明:土壤含水量与容重存在极显著的负相关性,有机质与p H、有效磷均存在显著的正相关性,与全氮存在极显著相关关系;有效磷与全氮也存在显著正相关性。     

草原矿区苔藓植物多样性及其与土壤理化性质的关系

以内蒙古半干旱区草原的代表煤矿—胜利煤矿及周边的贝子庙、植物园、南山水库为研究区,通过对苔藓植物群落特征和土壤理化性质的相关性研究,分析了复垦过程中土壤对苔藓植物分布的影响.结果表明,胜利矿区苔藓植物有4科6属7种,各生境苔藓总盖度排序为贝子庙>植物园>矿区南排土场>水库>人工林>矿区北排土场.多样性指数分析结果表明,南排土场苔藓群落物种复杂程度高.对苔藓植物群落盖度与土壤理化性质的相关性分析表明,土壤pH值、粉粒含量、沙粒含量和石砾含量对苔藓植物的分布都有显著影响.通过对苔藓植物群落结构与土壤理化性质的多元分析,发现不同研究区苔藓植物群落结构的差异性与环境因子的综合影响有关.     

葛仙米生长区水稻田土壤有效磷及总磷探讨

为了探明葛仙米生长区水稻田土壤含磷量状况,弄清楚葛仙米生长区水稻田有效磷及总磷含量特点及其影响因素.随机采集代表性水稻田土壤,测定其中有效磷及总磷含量,采集水稻田土壤样9个,确定两个水稻田土壤剖面(0～30cm厚度),测定结果如下:葛仙米生长区水稻田表层土壤和剖面土有效磷含量极其丰富;表层土壤有效磷含量变化范围为51 ～ 270 mg/kg,平均值为177 mg/kg;剖面土有效磷含量变化范围在99.75 ～ 241.5 mg/kg,有一峰值,有效磷含量根际土壤层低于2～5em(峰值处).总磷含量范围在279～ 1354 mg/kg.同时对土壤水稻田表层土壤样进一步做土壤蔗糖酶、脲酶、蛋白酶、碱性磷酸酶、纤维素酶活性检测,结果分析显示土壤蔗糖酶与有效磷有极显著相关性,其它酶无显著相关性.葛仙米生长区水稻田土壤蔗糖酶维持在47.707～ 55.031 mg/(g·d)之间.多元回归方程为:y(有效磷含)mg/kg=113.653+2.11x(蔗糖酶活性mg/(g·d)).     

土壤重金属与土壤理化性质的空间变异及研究

对研究区的部分土壤理化性质及土壤重金属的空间变异特性进行了分析,均表现出一定的空间变异性,并通过克里格插值得到它们的空间分布格局,表现出了一定的相似性,说明土壤理化性质与土壤重金属在空间分布上存在一定的相关性;通过对它们之间的空间相关性分析,表明克里格插值结果与实际计算结果是一致的,结果表明,土壤有机质、pH及各粒级含量土壤与Cu,Hg,As含量的相关性显著,与Zn,Pb和Cr为中等相关,且均为正相关,而与Cd的相关性不显著.在实际生产中,可以通过土壤部分理化性质来估计土壤重金属的分布特征.     

郑州市典型城市土壤剖面Zn、Ni分布特征分析

为探讨城市土壤重金属的分布、成因及迁移特征,选取郑州市不同功能区土壤9个典型剖面,2个城郊对照剖面,对Zn、Ni含量及其剖面分布进行分析.结果表明:郑州市城市土壤Zn含量与城郊对照土壤存在显著差异;城市土壤Zn含量变幅为17.05～1 400.72 mg/kg,空间变异非常大,平均值为306.67 mg/kg,高于土壤环境质量Ⅱ级标准,存在一定程度的Zn污染;城市土壤Ni含量变幅为6.70～22.33 mg/kg,平均值为12.41 mg/kg,均低于土壤背景含量,不存在Ni污染.城市土壤Zn、Ni含量的剖面分布比较复杂;土壤Zn的剖面分布与居民生活、工业以及交通等人类活动关系密切,具有在表层和亚表层累积的特点;土壤Ni含量大小主要受成土母质影响,垂直分布及迁移主要受城市人类活动扰动的制约而无一定规律.土壤中Zn含量与土壤理化性质不存在相关关系,而Ni含量与土壤粘粒、阳离子交换量等具有显著的正相关关系.     

霍侯一级路两侧土壤磁化率空间分布及其对重金属污染指示意义

以霍侯一级路表层土壤为对象,测定土样的磁化率、重金属(Pb、Cu、Zn)含量和理化指标,利用统计分析对重金属来源进行分析并对污染做出评价.结果表明:公路两侧土壤的低频和频率磁化率均值分别为77×10~(-8) m~3kg~(-1)和5.46%,土壤中超顺磁颗粒含量较少,磁化率的高值主要由人为活动产生的磁性颗粒沉积造成.随着到公路距离的增大,低频磁化率减小,而频率磁化率增大.Pb、Cu、Zn的含量分别为33.76-150.45mg/kg、18.41-67.86mg/kg和40.53-240.67mg/kg,都不同程度的超过山西土壤背景值.低频磁化率与pH、频率磁化率呈显著负相关,与砂粒含量正相关,而频率磁化率与粘粒含量呈负相关,有机质与磁化率表现弱相关,三种重金属之间相关性也很高.污染评价表明重金属的污染程度由强至弱依次为:PbZnCu,土壤环境总体处于中度污染.另外,基于磁化率的土壤分级标准得出的土壤污染程度也符合积累指数计算得到的结果,但此法的适用范围还有待于进一步的研究.     

四川凉山州野生蘑菇重金属汞和砷含量分析

检测了采自于四川省凉山州16种野生蘑菇的汞和砷含量.所有样品中,大白菇(Russula delica)具有最高的汞含量,为0.8607mg/kg干物质,其次为美味牛肝菌(Boletus edulis),汞含量0.7625mg/kg干物质.在采集地土壤中4个样点未检出汞的情况下,有3个样点采集的蘑菇中均有汞的检出,说明野生蘑菇对汞元素强烈的积累能力.采于四川会理锌矿区林家山的喇叭陀螺菌(Gomphusfloccosus)具有最强的积累砷的能力,子实体中的砷含量为1.9581—4.0035mg/kg干物质,其次为白杯伞(C litocybe phyllophila)子实体,砷的含量3.6418mg/kg干物质.采于会理县锌矿区的松塔牛肝菌(Strobilomyces strobilaceus)和采于西昌市大箐山林场的美味牛肝菌子实体中未检出砷含量.表明不同种类蘑菇积累汞和砷的能力不同;不同采集地同种蘑菇对砷和汞的积累能力也不同;蘑菇对汞和砷的积累与土壤中汞和砷的含量有关.     

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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