水平隧道管道固定墩推力虚功原理解答及应用

建立进出洞口处设置固定墩的水平隧道管道超静定结构力学计算模型,在求解基本假设的前提下,提出隧道管道"驻点"的概念,同时考虑隧道管道弯头处节点位移变形协调条件,采用虚功原理对隧道管道固定墩推力进行理论分析,得出考虑管墩摩擦和不考虑管墩摩擦情况下的解析计算公式.应用此解析公式和4套管道有限元分析软件(Ansys,Autopipe,Algor,CaesarⅡ),对西气东输二线管道工程X80钢级、管径1 219 mm的隧道管道固定墩推力进行计算分析.结果表明,固定墩推力随着管径、壁厚的增加而增大,其关系近似呈线性;解析解和有限元计算结果吻合较好,其最大相对计算误差仅为4.2%,说明解析公式计算结果可以满足工程需要,验证了分析结果的正确性.     

无补偿直埋供热管道固定墩设计探讨

供热管道无补偿直埋敷设冷安装施工中、固定墩的设置最关键的单位工程。本文探讨了土层冻深与管道推力的关系，融化土层应的变化，等与固定墩设计的有关问题。     

无补偿冷安装直埋供热管道固定墩设计几个问题的分析

分析了无补偿冷安装直埋供热管道固定墩地耐力、管道轴向推力，固定墩受力等问题。     

埋地热输管线固定墩选形试验研究

为充分利用埋地管线固定墩材料的承载能力，必须加大墩子迎土面积，且墩子的尺寸应经优化计算。本试验验证了优化设计的燕翅墩的承载能力。试验结果表明，新设计的固定墩的承载能力比原有固定墩大得多，经济效益明显。     

直埋管道固定墩结构探讨

随着管道直埋技术的成熟,管道直埋已在全国范围普及．直埋具有许多优点,如施工速度快．占地小,投资低等．但是大直径管道推力通常很大,固定墩的设计形式,将直接影响到工程造价和安全运行．分析了固定墩的受力状态,对其设计方法进行了一些探讨．     

无补偿直埋供热管道支架式固定支座的设计

对无补偿直埋供热管道固定墩的设计提出新的想法，拟采用支架式固定支座代替混凝土固定墩，以避免原有固定墩体积大、工程造价高易下沉等缺陷，并对设计中管道轴向推力、土壤与管道摩擦力、地耐力等的计算及理论依据进行了阐述．     

集中供热管网中直埋蒸汽管道的设计

本文结合工程实际论述直埋蒸汽管网设计中几个方面的问题，包括：将管网合理的划分管段；管网热补偿的设计；合理布置管网的疏水点；合理的设计管道的埋深；固定墩的设计及钢外套管的应力计算；管件的设置等。设计的合理是工程成功的前提保证。     

有关城市地下综合管廊结构设计经验

本文对城市地下综合管廊和供热管道直埋敷设固定墩设计中经常遇到的具体问题及解决方法进行论述，实用性较强，对于地下综合管廊及直埋热力管道设计具有可参考性。     

直埋管道弯头受力分析及设计方法

在管道敷设中，不可避免地要用到弯头。对直埋弯头受力计算办法作了简要介绍，并提出了对弯头处的具体处理措施，总结了直埋弯头设计的一些方法。     

高压大口径油气管道跨长计算

基于几何非线性,考虑当量轴向力(S₀)对管道挠曲的影响,提出了有或无固定墩单跨无补偿器管道强度计算方程。有固定墩跨越管道的设计计算是显式的。对于无固定墩两端埋地跨越管道,认为埋地管道的横向反力和轴向摩擦力分别与其横、轴向位移成正比,内力和变形计算最终可归结为两个非线性方程的求解,管道的自振固有频率可由特征方程数值解求得。提出了S₀为压力或拉力的显式判别式。并区分S₀为压力、零、拉力,列出内力、挠度、频率计算方程。介绍了静强度验算和动力设计的方法,给出了算例。     

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

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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