层次分析法在管道穿越河流方案选择中的应用

引入层次分析法,解决大口径油气管道河流穿越的方案选择问题。介绍了层次分析法的基本原理,详细论述了用层次分析法进行大口径油气管道河流穿越方案选择的步骤,以施工周期、河床适应性、施工工艺复杂性、对其它行业的影响、投资为评价因素,构建了最佳河流穿越方案选择的层次结构模型,并应用层次分析法对输气管道唐河穿越方案进行了分析,得出了多个穿越方案对于最佳河流穿越方案的相对权重,最后确定水平定向钻穿越为唐河最佳穿越方案。     

地质雷达技术在管道河流地层划分中的应用

该文从河流穿越岩土工程勘察中遇到的问题入手,引入地质雷达技术,并通过工程实例介绍了雷达技术在河流穿越中的应用,通过雷达成果剖面与工程地质钻探剖面的对比分析,体现了雷达技术的应用优势,有效的填补了钻孔间的盲区,弥补了常规岩土勘察技术中的不足,为输油气管道河流穿越勘察增加了一种新方法。     

复杂地质条件下定向钻穿越技术在油气管道施工中的应用

油气管道施工中,沿线多处经过公（铁）路、河流、峡谷、大山等穿（跨）越点,都需要采取特殊的穿（跨）越施工方法。本文就复杂地质条件下定向钻穿越技术在油气管道施工中的应用进行了深入的探讨,提出了自己的建议和看法,具有一定的参考价值。     

长输管道河流穿越技术探讨

长输管道是现代油、气资源开发利用的重要基础,其对提高油、气资源的运输安全有着重要的意义。在长输管道设计、建设中,长输管道的河流穿越是设计建设中所面临的重要问题。如何科学利用长输管道河流穿越技术进行长输管道建设是管道设计施工的首要工作。本文从长输管道河流穿越需求分析入手,对长输管道河流穿越技术应用进行了简要论述。     

定向钻穿越的质量控制探讨

在油气管道工程的施工过程中,油气管道定向钻穿越工程技术要求高、施工风险大,结合我国地域辽阔,地理情况复杂多样的特点,给管道定向钻穿越增加了难度,增大了其定向钻穿越的风险。针对油气管道定向钻穿越过程中存在的施工风险因素,特对定向钻穿越施工前、施工中风险预测、质量控制、穿越质量监管重点、防范等方面作一探讨,为定向钻穿越工程提供宝贵的资料和可借鉴的经验,从而有助于定向钻穿越的顺利完成。     

机坪输油管道荷载附加应力分析

应用ABAQUS有限元软件,考虑管土相互作用,建立并验证了管道结构有限元分析模型.应用该模型,分析了管周附加应力的分布特征,计算了飞机、施工重型车辆和压路机荷载作用下,管道附加应力及其引起的管道结构应力和变形随管道埋深的变化规律.结果表明:不同管道埋深对应的管周附加应力在管顶至管两侧60°的范围内有显著差异,且该范围内附加应力近似呈抛物线分布.即使管道埋深小至1倍管径时,飞机荷载和施工重型车辆荷载引起的管道结构应力和变形仍远小于容许值,而压路机高振幅振动压应力引起的管道结构应力达到管道强度失效的临界标准,是管道承受的最不利外荷载类型,对管道埋深有重要影响.     

油气输送管道应力分析及应变设计研究

人类进入21世纪,能源的全球供求矛盾呈现日益突出的趋势。如何保障我国石油安全有效地供给,已经成为我们面临的巨大挑战。该文针对油气输送管道所受的各种应力的分析,展开了基于应变的油气输送管道的设计讨论。若想对抗各种应力对油气输送管道的损害,需要加强油气输送管道强度和韧性。     

复杂荷载作用下空冷系统排汽管道力学性能分析——以火电厂空冷岛为例

目的研究火电厂空冷系统排汽管道应力分布情况,确定用于设计的最不利应力分布模式.方法以火电厂空冷岛为例,采用《钢制压力容器分析设计标准》(JB4732-1995)中计算薄膜应力的方法,考虑将基本载荷、地震荷载及风荷载进行组合,形成各种组合工况,应用ANSYS对某300 MW火电厂空冷岛系统的排汽管道进行大量的仿真分析,并对计算结果进行整理.结果各工况结果中管道应力最大的区域发生在三通,该处一次局部薄膜应力最大值为236 MPa,小于应力限值SⅡ=259 M Pa;除三通外其他区域在各种荷载工况下的最大薄膜应力均较小.其中与-X方向风荷载组合的各计算工况中,管道应力水平比之没有风荷载作用的相对较高,说明风荷载对管道应力影响较大,原因是管道属于高耸结构,且上部结构迎风面积较大.薄膜应力与弯曲应力求和后最大值为280 MPa,该应力为一次应力加二次应力,远小于限值SⅣ=518 M Pa.结论管道应力最大的区域为三通,三通区域的应力水平远高于其他区域,最终得出危险荷载工况作用下管道支座、三通、下部三通、折角以及盖板的应力分布,为300 MW直接空冷排汽管道提供设计依据.     

穿越公路输气管道力学性状影响因素研究

穿越道路管道在长距离输气管道中占有较大比例,而埋设在路面下的管道所承受的主要荷载之一就是车辆荷载,随着经济与交通运输业的迅猛发展,由车辆荷载引起的埋地管道的失效与破坏问题越来越严重.鉴于此,通过选取适当的材料本构关系、接触参数及车辆荷载模型,建立起车辆荷载作用下埋地输气管道的有限元模型并利用数值模拟和算例验证等方法,对车辆荷载作用下埋地输气管道的力学性状进行了分析和模拟.     

卵石层地质条件下定向钻穿越的技术优化

本文结合江西天然气管道工程撩河定向钻穿越工程的设计及施工情况,对穿越地段曲线设计、管道壁厚选取、进场道路、卵石层处理、管线回拖等方面的技术难点进行了研究分析,并提出了最优的解决方案,其中定向钻穿越入土角度一般控制在5～20°,出土角度一般控制在4～26°为宜;定向钻穿越河流的曲率半径不小于l500D;计算管道的最小壁厚时,必须考虑管道壁厚计算是在最小屈服极限条件下,管道能够承受同拖力作用的最小壁厚;根据已有的道路合理选择穿越位置时,必须考虑钻机进场的道路;水平定向钻穿越两岸砂卵石层的河流时,建议采用套管隔离卵石层的做法来穿越卵石层,并根据回拖场地情况提出回拖方式。     

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     

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

正~~     

Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has