三层网架的优化设计研究

通过对不同屋面组成、不同跨度和不同支承位置的4种形式的三层网架进行优化分析、求得了在给定条件下的最优网格尺寸和网架高度。通过二层与三层网架的对比计算分析、提出了三层网架的适用范围。     

使用多层组合外套的船用液压联轴器的 最优极限承载能力分析

比较船用液压联轴器的单层、双层、三层组合外套进行受力和强度分析,分析了三种方式的最优极限承载能力.研究表明,船用液压联轴器使用双层组合外套比单层弹性极限承载能力提高了17.43%,使用三层组合外套比单层弹性极限承载能力提高了24.17%.使用三层组合外套比双层组合外套弹性极限承载能力仅提高了6.74%,但是三层组合外套安装工艺复杂、生产成本较高,从经济分析考虑在船舶及大型机械部件上大多采用双层组合外套.     

双层柱面组合网壳的滞回特性模拟

针对单层网壳跨度小和双层网壳耗钢量大的缺点,应用大型通用有限元软件ANSYS对双层柱面组合网壳进行了滞回特性分析。介绍了双层柱面组合网壳具有跨度大和低耗钢量等。它充分利用了混凝土的高抗压强度和低廉的造价,采用钢筋混凝土上弦板来代替一般网壳的上弦杆,从而形成了一种钢结构与钢筋混凝体结构协同工作的组合结构,即双层柱面组合网壳。组合网壳是一种受力合理的空间结构,也是一种板系、梁系与杆系协同工作的结构体系。国内外对双层柱面组合网壳结构在地震和低周期反复荷载作用下滞回特性的研究很少,着重对地震和低周期反复荷载作用下的双层柱面组合网壳结构进行研究分析,得出双层柱面组合网壳结构的频谱相当密集;其具有良好的抗震性能,其滞回曲线比较饱满,未发生捏缩现象。双层柱面组合网壳是一种很有发展潜力的结构形式。     

三层网架的静力分析和结构选型

通过对不同支承条件不同边长比的七种形式的六十二种三层网架进行静力特性研究,得出了三层网架内力、反力及位移的分布规律。讨论了三层网架的边桁架及中层弦杆的作用。提出了不同条件下三层网架的选型问题。     

大跨度三层与双层新型组合式平板网架结构

介绍一种新型组合式平板网架，以适应跨度在100m以上的特大跨度建筑中应用。用三层网架与两层网架合理组合，达到覆盖跨度大，以保证刚度和强度的条件下，作到节约用钢量的目的。     

三层网架模型试验研究

本文介绍了4.4×6.8×0.48m棋盘形四角锥三层网架模型试验的方法及结果。试验表明,三层网架是一种安全可靠、刚度较大,内力分布更加均匀的新型结构。网架挠度、杆件内力的实测值和按空间桁架位移法计算的理论值吻合较好。     

某体育馆屋面网架结构设计

以实际工程为背景,对三层网架(局部双层)的结构设计做了简要介绍,对网架支座设计中常见的问题进行了探讨并提出了解决方案。     

三层及多层网架的应用和研究

本文论述了什么是三层,多层网架,该种网架的用途,国内外应用的实例,以及国外的研究概况。三层网架的性能,不仅取决于其形式和用钢量,而且受到支承的布置、边支撑与中层的影响。本文着重论述了常用的三层网架的形式,边支撑和中层的作用,支承的布置方法等,以及它们对杆件內力和挠度的影响。     

网架系杆钢管混凝土拱组合桥的研究

提出了一种新的桥梁结构形式———网架系杆钢管混凝土拱组合桥．并将这一构思首先应用于一座５０ｍ跨１０ｍ宽的双车道公路桥中．结合空间网架结构、钢管混凝土结构、系杆拱桥的受力特点,阐述了这种新型式桥的结构构成、受力机理、分析方法及美学特性     

空间网架结构边界约束对网架温度应力的影响

结合边界约束条件对网架温度应力的影响来控制网架结构边界条件的选型。分析了网架结构在弹性约束、固定和强迫位移条件下的总刚度矩阵处理方法；介绍了网架结构在均匀温度场变化下，由于杆件不能自由的热胀冷缩而产生了温度应力，同时阐述了它的分析方法。并且根据有限元理论和Visual Basic6.0编程语言编制了温度应力分析程序，针对具体的工程实例来探讨温度应力在边界的切线与法线方向约束条件分别选取固定、弹性、放松三种情况进行五种组合的条件下杆件温度应力的变化规律，从而确定了网架的边界形式。     

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     

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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