空腹式钢筋混凝土板拱桥荷载横向分布研究

为了进一步探究空腹式钢筋混凝土板拱桥的荷载横向分布规律,简化桥梁计算,通过改变空间模型中虚拟横梁的间距及抗弯刚度,分析了主拱圈拱顶截面的横向分布规律;并通过荷载试验结果对分析的结论进行验证。结果表明:当虚拟横梁间距取虚拟纵梁间距的1.5倍及虚拟横梁抗弯刚度调整为主梁的5倍时,计算出空腹式板拱桥跨中横向分布理论值与实测值最大误差在1.2%以内,具有一定的精确性,可为实际工程设计提供参考依据。     

斜梁桥荷载横向分布的能量法

采用能量原理在广义刚性横梁法的基本假定下,横梁为不变形的刚性梁,根据单根斜梁在单位力(或单位矩)作用下的一般计算公式,导出了斜梁桥荷载横向分布的计算公式,推出了斜梁桥通用的荷载横向分布的计算公式.并对正梁桥、平行四边形斜梁桥等几种特例下各系数进行了计算.该方法特别适用于可以简化为梁格的窄梁桥荷载横向分布计算.     

斜梁桥荷载横向分布的能量法

本文采用能量原理在刚性横梁的基本假定下,推出了对正、斜桥通用的荷载横向分布的计算公式。并对几种特殊例下的系数进行了计算。本文方法特别适用于可以简化为梁格的窄梁桥荷载横向分布计算。     

公路梁桥主梁剪力荷载横向分布计算

本文应用梁格分析方法,简述了公路梁桥主梁剪力荷载横向分布的特性。对由多主梁和三、四或五片横梁组成的梁格作了分析。本文的目的在于提出计算主梁剪力荷载横向分布系数的近似方法,并用电算编制了设计用表。     

基于静载试验的Ⅰ型钢-混组合梁桥的荷载横向分布研究

为探讨装配式Ⅰ型钢-混组合梁桥的荷载横向分布规律,以跨径为30 m的钢-混组合简支梁桥为研究对象,通过MIDAS Civil有限元软件建立梁格模型反算其横向分布系数,同时采用偏心压力法、修正的偏心压力法、刚接板梁法、"G-M法"等计算其横向分布系数,与静载试验结果进行对比,研究其荷载横向分布规律.试验结果表明:对于跨径...     

非规整刚接T梁桥荷载横向分布计算方法

荷载横向分布系数是既有T梁桥加宽设计的关键问题之一。根据刚接梁法基本假定,应用力法原理推导了刚接梁法一般力法方程,可用于由截面特性和间距不同的T梁组成的非规整刚接T梁桥荷载横向分布计算。实例计算表明该方法的计算精度满足工程要求。同时对一座非规整加宽T梁桥进行了计算分析,计算结果与空间实体有限元结果吻合较好。基于荷载横向分布分析和新旧规范对比,分析了加宽方案。     

三跨连续四肋拱桥横向分布研究

以某公园三跨连续四肋拱桥为例,运用midas有限元分析软件建立空间梁格模型,探索多跨多肋拱桥各拱肋荷载横向分布规律,并采用midas Civil空间梁格模型施加单位力法得到该桥各拱肋的荷载横向分布系数.研究结果表明:在偏载情况下,偏载一侧的两根肋承担了大部分荷载;在正载情况下,四个拱肋的受力呈现对称性,荷载主要由中间的两根拱肋承担.     

钢-混凝土组合简支桥面连续结构横向应力分析

针对钢-混组合简支梁桥的桥面连续结构开裂等病害,围绕桥面连接板的横桥向应力问题,采用线弹性理论和板的偏微分方程进行分析,得出了桥面连接板挠度和应力的分布函数,建立非线性有限元模型,并进行实桥荷载试验.通过比较理论解、有限元解和实测试验结果,证实了理论解和有限元的有效性.根据得到的分布函数,发现横桥向和纵桥向上的最大拉应力出现在钢梁端部位置的连接板的上缘.此外,还分析了连接板区域尺寸变化对横桥向应力峰值的影响,包括纵梁端部距支座的长度、纵梁的间距以及连接板区域整体尺寸变化.结果表明：较小的纵梁间距和较长的纵梁端部与支撑之间的距离会导致连接板中的横向拉应力峰值增加,并提高横向拉应力在总应力中的占比,从而导致桥面连接板早于设计荷载开裂.因此对于纵梁间距较小、梁端长度较长的钢-混组合简支梁桥桥面连续结构,仅计算其纵桥向受力性能会导致计算结果偏危险,建议按照本文方法考虑横桥向应力对桥面连接板的影响.     

用梁格法模拟斜交板梁的荷载横向分布

本文介绍的是用梁格法模拟斜交板梁桥荷载试验时的荷载横向分布问题,由于斜交板梁荷载横向分布的复杂性,通过简化计算的方法和ANSYS的BEAM44梁单元计算的方法求出横向分系数,得出理论应力与挠度值和试验相比较,分析讨论其斜交空心板梁横向分布其根据实际情况计算适用性及准确性。     

移动荷载作用下三跨钢-混组合连续梁桥面铺装动态响应

为研究移动荷载作用下三跨钢-混组合连续梁桥面铺装层响应,建立了一种三跨钢-混组合连续梁模型,桥面铺装层采用沥青混合料黏弹属性,移动荷载采用DLOAD与UTRACLOAD子程序实现.结果表明,上面层、下面层、水泥混凝土层及钢板层的最大垂向挠度值比纵梁大17%.由于纵梁与横梁支撑,纵梁的最大垂向挠度比非纵梁小6.6%,横梁最大垂向挠度比非横梁小3.1%.剪力钉与混凝土全接触时的竖向挠度最大,黏结与接触共同作用时的竖向挠度次之,全黏结时的竖向挠度最小.桥面铺装层承受垂向压应力,上、下面层承受横向压应力,钢板层承受横向拉应力,上面层与水泥混凝土层承受纵向压应力,下面层既承受纵向压应力又承受纵向拉应力,钢板层承受纵向拉应力.     

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