北江枯水期多环芳烃的污染分布特征与风险评估

2016年12月北江清远段采集19个水和表层沉积物样品,采用气相色谱质谱(GCMS)法测定了样品中的多环芳烃(PAHs),分析了枯水期北江水环境中PAHs的污染水平,并对生态风险进行了评价。结果表明,枯水期北江清远段水中PAHs浓度范围为41. 2～413. 8 ng·L~(-1),主要以二环芳烃和三环芳烃为主,与国内外已报道河流湖泊相比,北江清远段水中PAHs污染处于中等污染水平;沉积物中PAHs浓度范围为54. 8～951. 5ng·g~(-1),以三环芳烃和四环芳烃为主,与国内外河流湖泊沉积物相比较,处于低污染水平。运用特征比值法对PAHs来源进行分析,北江清远段水和沉积物中枯水期PAHs污染来源主要由燃烧源所致,部分采样点存在混合源。通过计算终生致癌风险(ILCR)模型对北江清远段水体进行健康风险评价,结果表明,枯水期各采样点的致癌风险可忽略,婴幼儿的PAHs致癌风险高于青少年和成人。采用效应区间低、中值法(ERL/ERM)对枯水期表层沉积物中PAHs进行生态风险评价,个别点位表层沉积物中Dib超出ERL值,对生态环境潜在负面效应较小。     

甲基取代多环芳烃的致癌活性与其分子轨道之间的关系

一前言甲基多环芳烃是多环芳烃的重要类型,在香烟的烟中、汽车的排气中、煤气和煤燃烧的排出物中都有足够量的甲基取代多环芳烃,绝大多数的甲基取代物和其母体多环芳烃之间致癌性差别不大,但有些甲基取代多环芳烃却在致癌性方面明显地不同于其母体多环烃的致癌性。尤其是四个环分子左右的分子表现得十分突出。例如(艹屈),其分子结构式如图1所示它表现较小的致癌活性,其甲基衍生物MC,在1,2,3,4,7,8,9,10,位置上的甲基取代(艹屈)仅表现较小的致癌活性,而6位(或12位)仅表现稍强的活性,但是5(或11)位的甲基取代(艹屈)却表现与苯并(a)芘相当的致癌活性.又例如苯并(a)蒽其分子结构式     

多环芳烃致癌活性的MO指标

多环芳烃的致癌活性和它的结构有关,有些人曾从分子轨道理论的观点研究致癌性和分子特性的关系,以期找出能反映致癌活性的结构指标。早期Pullman等曾提出了多环芳烃致癌的量子理论,他们根据定位能的计算进行了总结,发现致癌物有高电子密度的活性K区,可以和蛋白质或核酸受体发生亲电反应,同时还有电子密度较低的非活性L区,在L区则可发生代谢去活化的反应。当K区的邻位定位能(包括键及碳原子)小于3.31β,     

湄洲湾表层沉积物中多环芳烃的含量分布及来源分析

2000年10月在湄洲湾海域6个站位采集表层沉积物样。采用GC／MS法分析其多环芳烃的含量。结果显示：在这些沉积物样中，美国环保署优控的16种多环芳烃的含量分布较为均匀，其范围为196．7～299．7ng／g，平均值为256．1ng／g；显著低于长江口、珠江口及其欧美主要港口表层沉积物中多环芳烃的含量。对多环芳烃特征组分的比值(菲／蒽比值，荧蒽／芘比值)及16种多环芳烃中四、五和六环总含量的百分比的分析表明：湄洲湾表层沉积物的多环芳烃主要来源于燃料的高温燃烧。     

太湖表层沉积物中的多环芳烃及其毒性评估

通过有机萃取和色质联用分析太湖沉积物中15个多环芳烃,其中12个被检出,包括5种世界卫生组织规定的PAHs代表物．分析结果表明,太湖北部的多环芳烃总量明显高于中部和南部。低分子量多环芳烃与高分子量多环芳烃的含量差别不大,但在地域上比例有所变化;根据荧蒽／芘(Fl／Py)的比值统计,多环芳烃主要来源于石油燃烧,部分为煤和木材的燃烧形成．基于沉积物中多环芳烃的环境质量标准,在9种同系物中有3种超过毒性风险效应低值,但都小于毒性风险效应中值,因此太湖沉积物中多环芳烃的环境毒性相对较低．太湖沉积物中多环芳烃的不均匀分布也反映了沿湖地区的经济发展程度．     

多环芳烃的环境分布及其生物修复研究进展

围绕环境中广泛存在的有机有毒物质多环芳烃，介绍了该类污染物质来源、性质、危害及不同环境领域中污染现状，尤其针对不同领域中其分布、存在形态、归趋模式等进行了综合评述，讨论了国内外多环芳烃污染土壤、海洋及沉积物所应用的生物修复原理和相应科学技术研究，其中包括微生物基本代谢原理、微生物共代谢机理和应用，阐述了微生物基因调制研究的最新动态和通过激发微生物生物活性，加速多环芳烃降解的多种技术手段，最后总结了多环芳烃环境污染的有关控制途径及其管理规范，并展望了生物修复研究的发展前景。     

天津地区鱼塘沉积物中多环芳烃污染浅析

对天津地区典型鱼塘沉积物中16种多环芳烃（PAH）的含量进行了测定，结果表明，高庄子鱼塘和小南河鱼塘沉积物中多环芳烃的主要来源为工业废水排放所输入的石油类物质；由于微生物、含氧酸根等元素对多环芳烃的降解起着促进作用，污水鱼塘沉积物中多环芳烃的残留量要低于清水鱼塘，据此提出了对策和建议。     

松花江吉林市江段江水中多环芳烃来源的研究

为研究松花江吉林市江段中多环芳烃来源,采集了松花江吉林市江段2013年5月(平水期)、2013年8月(丰水期)和2014年1月(枯水期)的江水、沉积物、废水、降尘、降水及地表径流样品,测定了其中16种多环芳烃的含量,利用主成分分析法对降水中多环芳烃的来源进行分析,同时计算松花江吉林市江段中多环芳烃的输入通量。结果表明:江水中多环芳烃来源较为广泛,不同水期江水中多环芳烃来源有一定的差别,但所有水期石油源和交通源均是江水中多环芳烃的主要来源,平水期和丰水期沉积物中PAHs的主要来源是燃烧源,其次是石油源。松花江吉林市江段的多环芳烃最主要是通过上游来水的方式进入到江水中,其它输入方式按输入通量由多到少依次为废水排放、降尘、降水、地表径流。     

水环境中多环芳烃的光降解研究进展

多环芳烃是一类可致癌、致畸、致突变的持久性有机污染物,对人体和环境存在着危害.文章主要针对水环境中多环芳烃的来源与危害、水中光降解多环芳烃的一些影响因素、多环芳烃的光降解产物的鉴定进行了简单的阐述.     

油田居住区土壤中多环芳烃污染特征与风险评价：以胜利油田为例

油田城市作为一类与采油厂共同发展起来的特殊城市,长期的原油开采和城市活动导致了其居住区土壤多环芳烃污染特征的特殊性和复杂性。本文以胜利油田内的居民区土壤为研究对象,调查了城镇、郊区和农村3种不同土地利用类型的45个土壤样品,从污染水平、空间分布和潜在来源等方面阐明了研究区土壤中16种多环芳烃的污染特征,并且根据毒性当量计算了16种多环芳烃的终生癌症风险增量。结果表明：16种多环芳烃总量的浓度范围为16.24～685.2 ng/g,平均为（126.0±158.3）ng/g。在三种土壤类型中,城镇和郊区土壤普遍受到多环芳烃的污染,且主要成分为菲、?、芘和荧蒽。在土壤剖面中,表层多环芳烃的浓度水平通常高于底层,该趋势在郊区和城市地区的剖面中尤为明显。通过分析土壤中多环芳烃的特征比值结果以及多环芳烃与与总石油烃含量的相关性,揭示了油田居民区土壤中多环芳烃主要来源于石油污染。致癌风险评估结果指出了油田区农村、城郊的表层土壤以及城区的所有土层土壤中的多环芳烃均存在致癌风险,需要研究人员和政府人员对这类地区中的多环芳烃污染开展进一步的监测、分析和管理工作。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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     

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