黄河入海口表层沉积物中多环芳烃（PAHs）分布特征及来源

对丰水期、枯水期黄河入海口8个站位表层沉积物中多环芳烃（PAHs）进行提取分离,利用气相色谱-质谱联用仪（GCMS-QP2010）定量分析。丰水期沉积物中共检出15种2-5环PAHs,而枯水期沉积物中共检出25种2-6环PAHs。丰水期表层沉积物中PAHs的总浓度在90.13～351.36ng/g之间,枯水期表层沉积物中PAHs的总浓度在39.34～218.92ng/g之间。同国内外其它河口、海湾相比,黄河入海口沉积物中PAHs相对较低,PAHs含量、分布具有明显的季节性变化特征,丰水期PAHs浓度高于枯水期PAHs浓度。由多环芳烃参数菲/蒽、荧蒽/芘与甲基菲/菲比值表征黄河入海口表层沉积物中PAHs主要来源于燃料不完全燃烧。     

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．     

红枫湖表层沉积物中多环芳烃的分布及来源分析

对贵阳红枫湖表层沉积物16种优控多环芳烃进行了定量分析.结果表明,红枫湖沉积物中多环芳烃总含量为273.6～944.3 ng/g,具有不利的生物影响效应,存在养殖动物的食用安全隐患;其污染来源以高温燃烧产物为主,主要由化石燃料及木材的高温燃烧废气及工业和生活废水排放等人为污染引起的.     

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。     

舟山海域沉积物中多环芳烃的分布及来源

对舟山海域表层沉积物中多环芳烃的分布和来源进行了研究,利用快速溶剂萃取方法对样品进行前处理,再经气相色谱-串联质谱联用仪(GC-MS/MS)对26种多环芳烃进行检测,并采用主成分分析法对多环芳烃来源进行分析.结果表明:15种优控多环芳烃的总含量为10.5～521.8ng/g,其分布呈现沿岸高、外海低的特点;26种多环芳烃的总含量为13～2 422ng/g,主要来源于石油泄漏,如船舶和港口漏油,以及航道运输和船舶排污的影响,同时也受到汽车尾气排放和成岩来源的影响.     

淮河中游重化工聚集区干流水体中多环芳烃研究

淮河是中国七大河流之一,在中国国民经济发展中具有举足轻重的地位.有机物污染是淮河的主要污染形式.多环芳烃(PAHs)是一种典型持久性有机污染物(POPs),在水中的浓度较低.易于被悬浮物和沉积物吸附.为探讨淮河中游重化工聚集区干流水体中多环芳烃的含量和分布情况,2007年10月在淮南和蚌埠段采集悬浮物样品和表层沉积物样品.所采集的环境样品经自然风干后,利用二氯甲烷提取,无水硫酸钠和固相萃取柱组合净化,采用气相色谱-质谱联用法(GC-MS)同时定性和定量检测其PAHs含量,获得了美国EPA优先表中所列的16种PAHs含量数据,在此基础上探讨了淮河中游重化工聚集区干流水体悬浮物和沉积物样品中PAHs的分布特征.并初步分析了蚌埠市饮水源区蚌埠闸处PAHs的超标情况.结果表明:①淮河中游重化工聚集区干流水体环境样品中PAHs总含量变化幅度较大,其悬浮物浓度范围为1 169.44～4 048.86 ng/g,表层沉积物中浓度范围为91.98～1 292.52 ng/g;②就单一组分而言,悬浮物中萘含量最高,表层沉积物中二苯并[a,h]蒽最高;③受采样点环境和PAHs本身性质影响,悬浮物中PAHs量远大于其沉积物中量,整体呈现悬浮物中以低环PAHs为主、沉积物中以高环PAHs为主的特征;④根据<国家海洋沉积物质量标准>,蚌埠闸沉积物中PAHs超标严重,对蚌埠市的饮水安全产生一定的威胁,同时,此处悬浮物中PAHs含量也很高,潜在危害性更大,应给予重视.     

第二松花江流域水体表层沉积物多环芳烃的污染特征与暴露风险评价

考察第二松花江表层沉积物中16种多环芳烃类化合物(PAHs)的质量比.结果表明:16种PAHs的总质量比为350.0~3 877.4ng/g,平均质量比为1 322.6ng/g,4~6环相对丰度为58.5%,2~3环相对丰度为41.5%;PAHs在上游水区的质量比最高,与长江河口相近;除河源区外,大部分水域沉积物中PAHs人为来源为化石燃料的燃烧,少部分为石油源;除表层沉积物中芴和苊烯可能具有一定的暴露风险外,其他PAHs存在的暴露风险较小,即第二松花江沉积物PAHs总量远低于风险评估低值(ERL),存在的暴露风险较小.     

多环芳烃在新安江河流-水库体系表层沉积物中的分布、来源及生态风险评估

利用气相色谱-质谱联用仪(gas chromatography-mass spectrometer, GC-MS)分析了新安江河流-水库体系表层沉积物样品中16种优控多环芳烃(polycyclic aromatic hydrocarbons, PAHs)的含量.结果表明, 16种PAHs在表层沉积物样品中均有不同程度的检出,总浓度(∑_(16)PAHs)范围是260～1 652 ng/g dw (dry weight,干重),平均值为973 ng/g dw,以高分子量的PAHs为主.的区域是兰江∑_(16)PAHs值最高(1 530 ng/g dw),最低值出现在水库中心库区(600 ng/g dw). PAHs源解析表明,底泥中PAHs可能主要来源于煤和木材的燃烧.参考已有研究的分类标准,发现新安江上游、水库中心库区和富春江表层沉积物中PAHs处于中等污染水平,而水库回流区和兰江沉积物受到PAHs的污染较大.通过生态风险分析,发现所有底泥样品均可能存在急性毒理效应,但不存在频发性急性毒理效应.     

贵州省黔南地区表层土壤中多环芳烃分布特征

为了解黔南地区表层土壤中多环芳烃(PAHs)的污染状况,共采集12个县市土壤样品98份进行16种多环芳烃的定量分析,对其分布特征、污染水平进行了探讨.结果表明,土壤中PAHs检出含量为0.4~755.9μg/kg,其中芴和苯并(a)蒽为检出率最高的主要污染物,均值分别为4.47和6.95μg/kg,与国内其它地区报道相比,黔南地区表层土壤受到一定程度的PAHs污染,但处于较低的污染状态.     

骆马湖表层沉积物中多环芳烃的源解析

运用主因子分析和多元线性回归分析法对骆马湖表层沉积物中16种优控多环芳烃（PAHs）的来源进行源解析,探讨几种主要燃烧源PAHs的贡献率．结果表明,沉积物中PAHs主要来源于煤炭和秸秆燃烧以及交通工具尾气排放,累计贡献率为99．7％．     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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