矩形管道层流流动近似计算

本文利用变分方法推出了矩形管道中完全发展段层流流动的速度,继而讨论了矩形管道中的流量、沿程阻力系数和压力损失等。实验结果表明,本文的分析是可靠的。     

埋地供水管道的地震反应研究

本文介绍了目前国内外埋地供水管道的多种地震反应分析方法,并结合实际管道施工中的实例,比较了各种分析方法的计算结果,最后运用ANSYS有限元软件对管道与土壤环境进行了仿真模拟,得出了有限元分析结果,通过比较有限元分析结果和理论计算结果,进一步验证管道地震反应分析方法的可行性,为有限元法在埋地管道地震反应分析中的应用起到了推动作用。     

油气长输管道综合评价模型设计与实现

现有的管道安全评价模型普遍采用专家打分法等主观性方法,但在确定权重时,受主观意识影响较为严重,存在评价结果与现场实际吻合度不高、评价结果不够全面等缺点。笔者针对油气长输管道安全评价实施现状及评价需求,在对油气长输管道安全评价目标和特点分析基础上,确定了油气长输管道的主要评价指标,应用模糊数学方法建立了油气长输管道综合评价模型,并对评价模型的关键技术进行分析,其中综合运用变异系数法、层次分析法进行量化分析准则层权重,通过建立优先关系矩阵和模糊一致矩阵的方法确定指标层权重。通过算例验证了所推出模型的可行性和准确性。     

岩溶管流水力学模型的典型研究——以后寨地下河为例

岩溶区，地下管道中的水流不符合渗透定律，当岩溶管道被地下水充满形成承压管流系统，在性质上类似有压管路水流，因而应当采用水力学的原理对岩溶水运动进行描述。本文推出了有裂隙水均匀入渗时地下河管道沿程水头损失计算公式，并提出了岩溶管道等效直径的计算方法。用水力学模型对管道系统计算等效直径及预测管道水头损失值，与实测值基本一致，这些结果是可以接受的。研究成果表明，应用水力学原理解决岩溶管流区地下水运动问题具有良好的前景。     

泊肃叶公式的推导及实验验证

流体在管道内流动时,其流量与管道的几何尺寸,流体性质,管道两端的压差有关,其规律即泊肃叶公式。本文采用量纲分析法推出泊肃叶公式的基本形式,再用实验来验证。确定式中的比例常数k与泊肃叶公式中的常量8π等值。     

镶衬垫煤浆管道清水阻力损失预估方法

本文由流体运动方程式推出镶衬垫管道的沿程清水阻力损失预估方法。用平均速度梯度射线代替非圆形截面管道当量直径,在76mm管径管道系统实验结果与估算值相符。     

流体输送管道水击载荷动力学模拟分析

在流体输送管道中,因各种原因会发生水击现象,从而对管道以及管线上的设备造成危害。为深入了解管线水击现象的产生与发展过程、压力波动及其不稳定载荷对管道结构的影响并预防水击所带来的破坏作用,用管道应力分析、设计软件CAESAR II建立了某输送管线突然停泵造成管线中的压力波动影响的管道动力学模型,根据水击载荷频谱分析了在水击载荷动力作用下输送管道内各关键点的位移、应力和支反力,同时进行了输送管道系统的模态分析和固有频率分析。这些结果为合理设计输送管道、管道强度设计和消除水击现象提供了参考依据。     

双层海底管道隆起屈曲参数分析

海底管道在铺设安装过程中可能因为操作不当,使得管道在海底时存在局部的初始隆起.管道初始局部缺陷是诱发海底管道产生屈曲的潜在因素.管道轴向压力是导致海底管道发生屈曲的主要原因.当海底管道在高温载荷下工作时,管道将会由于温度变化引起轴向力的增大而发生隆起屈曲.对于双层管道来说,内管与外管之间的相互作用是非常复杂的,双层管的复杂结构导致其整体屈曲理论分析十分困难,因此提出了一种有限元模型,该模型利用管中管技术分析具有初始缺陷管道的隆起屈曲问题.基于该模型开展了参数分析,得到了管道初始不直度和环隙对海底高温管道发生隆起屈曲的影响趋势.同时这些计算结果对我国实际工程项目中的双层管隆起屈曲分析具有一定的参考价值.     

基于GZCORS的石化供气管道测量中的应用

本文以GZCORS在石化供气管道测量中的应用为研究对象,论文首先简要介绍了GZCORS系统的特点和功能,进而分析了GZCORS在石化供气管道测量中的应用模式,在此基础上,论文探讨了作业实施方法及测量结果,最后进行了误差分析,通过对比采用GZCORS系统和常规RTK测量方式两种方法得出的数据精度,总结出了GZCORS系统的优、缺点。     

沉降性浆体倾斜管道浓度分布的研究

首先推导了流体在倾斜管道中的速度分布模型,在此基础上,从固体颗粒在管道中的三种运动状态出发,提出了倾斜管道沉降性浆体浓度分布的计算模型,并用相关实验结果对所提出的模型进行了简单的验证。     

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     

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     

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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