新广州站中央采光带杂交结构受力性能分析

为了了解新广州火车站中央采光带杂交结构体系的受力性能,讨论了其下部索杆体系的预应力设计水平,分析了结构体系中柔性构件对其静力性能的影响,并对其进行了特征值屈曲分析和非线性屈曲分析,文章最后讨论了上弦钢杆件截面、钢拉杆和下弦拉索截面及其预应力对结构竖向刚度的影响.计算结果表明:杂交体系中下部索杆体系和上部面内钢拉杆可以较大地提高结构的刚度;该杂交结构体系满足整体稳定性的要求,但其端部区域是结构稳定的薄弱环节之一;结构的竖向刚度随着钢杆件截面的增大而增加;上弦钢拉杆的截面及预应力的增加对结构竖向刚度有一定的提高;下弦拉索截面对结构刚度的影响较大,但是其预应力值的影响较小.     

大跨度空间网格结构多维多点随机地震反应分析

对大跨度空间网格结构进行三向正交地震动的多点激励下的随机地震反应分析．建立了多维多点随 机地震动激励下的地震反应分析方法,并依据建筑抗震设计规范确定了平稳随机地震动功率谱密度的模型 参数．数值仿真分析了某柱距80 m的大跨度平板网架分别在一维地震动或三维地震动的一致激励、行波激 励和考虑部分相干效应的随机激励下的地震反应．结果表明:考虑地震动的空间效应后,关键杆件的内力 增幅可达30％;多维地震作用比单维地震作用下结构杆件的内力大．由此得出结论,对于大跨度空间网格 结构的地震反应分析,必须考虑多维地震动的多点激励．     

考虑上下协同工作大跨度储煤结构的抗震性能

为了研究多维地震作用下大跨度储煤结构的振动特性,通过对考虑上下部协同工作的双层网壳结构进行了多维地震响应分析,对比分析双层网壳结构在单维地震与多维地震动作用下的动力响应的差别,分析结果表明:采用一致地震激励的方法进行大跨度网壳结构的动力分析是不够完善的,在进行前期工程设计时,大跨度空间结构其上下协同工作的特性不容忽视,在多维一致地震作用下,整体结构的各杆件内力响应整体大于网壳结构,下部支承结构附近的节点位移和杆件内力变化较大;多点地震激励下的整体结构的杆件内力响应整体小于一致激励,当视波速取值较大时,杆件内力与一致激励较接近.可为今后类似大跨度空间结构工程参考和借鉴.     

两种典型空间结构多维多点激励下抗震分析

采用三角级数法模拟生成满足给定的相干函数和考虑三维地震分量相关性的非平稳人造地震动,基于直接输入位移法建立了地震动多维多点激励时程分析模型.选取两种典型大跨度空间结构为研究对象,分别计算分析了两种结构在地震动一维一致激励、一维多点激励和多维多点激励下的反应,并对多维多点激励下不同视波速情况引起的结构反应进行了对比分析.分析结果表明:地震动多点激励下两类结构大多数杆件的最大受力大于一致激励作用,多维多点激励下杆件内力计算结果与单维多点激励下的结果变化规律基本相似,单维多点激励给出偏于不安全的结果,不同的地震波视波速情况多维多点激励作用对大跨度结构地震反应影响很大.     

沥青路面结构早期破坏的动力特性分析

为了研究沥青路面结构早期破坏问题,采用三维有限元模型模拟沥青路面结构在动载作用下的响应情况,分析了弯沉、应力的变化规律.结果表明:在动载作用下,轮载中心处的弯沉和应力均较静载作用时小,但弯沉值的变化具有显著的波动性,轮载中心以外的其他任何点的弯沉值均可能出现大于静载作用时的弯沉;结构层表面拉应力和压应力交错出现,上面层的轮载边缘附近所产生的拉应力数值相对静载明显增大,沥青表面极易产生拉裂破坏, 与规范所规定的拉应力验算点有一定差异.建议在拉应力验算时,增加车轮边缘附近验算点,以保证路面结构表面不产生开裂破坏.     

偏心拉杆极值应力的电测法研究

基于组合变形理论推导了偏心拉杆危险点的拉、压应力计算公式;利用静态电阻应变仪及材料力学多功能台,采用半桥单臂惠斯通电桥测得了杆件材料的杨氏弹性模量及偏心拉杆的危险点应力;采用半桥双臂及全桥对臂法分别测得了轴向力及弯矩单独作用下的拉应变,并由胡克定律得到了偏心拉伸截面上的最大拉应力及压应力.研究表明,通过电测法所得危险点应力与理论值非常吻合,研究结果证实了方法的可行性.     

钢筋混凝土环形截面构件破坏的统一表达

通过对环形截面构件的研究,建立在复合受力务件下的统一破坏表达．首先建立截面的应力屈服方程;然后把截面应力用所施加的内力表达出来,代入屈服方程,得到环形截面构件在拉压、弯、剪、扭4种内力共同作用下破坏的统一表达式和相互作用曲线（面）．应用塑性力学、断裂力学和组合材料力学的成果,从理论的高度把钢筋混凝土构件破坏的形式统一起来,有较大的理论意义和实用价值．     

自由形态单层壳体栓接节点

针对自由形态(free-form)单层壳体中的栓接节点,运用ABAQUS通用有限元软件对多种工况作用下的节点承载力性能进行了计算机模拟.分析了螺栓预紧力和杆件轴向拉压应力等因素对节点刚度和承载能力的影响.理论分析和试验研究表明,栓接节点处连接截面在荷载作用下会产生明显的相对转动变形,整体结构分析时对这类连接不能按全刚接连接考虑.最后,在总结受力性能和破坏模式的基础上,给出了栓接节点的使用维护和工程设计建议.本文研究将为自由形态壳体结构中的栓接节点设计提供理论依据.     

自由形态单层壳体栓接节点承载力性能研究

针对自由形态（free-form）单层壳体中的栓接节点,运用ABAQUS通用有限元软件对多种工况作用下的节点承载力性能进行了计算机模拟.分析了螺栓预紧力和杆件轴向拉压应力等因素对节点刚度和承载能力的影响.理论分析和试验研究表明,栓接节点处连接截面在荷载作用下会产生明显的相对转动变形,整体结构分析时对这类连接不能按全刚接连接考虑.最后,在总结受力性能和破坏模式的基础上,给出了栓接节点的使用维护和工程设计建议.本文研究将为自由形态壳体结构中的栓接节点设计提供理论依据.     

碳纤维布用于墙体抗震加固方式的研究

以主拉应力破坏理论为基础,分析了在水平地震作用下,墙体内一点的主拉应力方向与该点水平剪应力和垂直压应力比值之间的关系,试验研究表明碳纤维布能够有效分担部分墙体拉应力. 针对不同类别的建筑物墙体,建议按其主拉应力方向粘贴碳纤维布.     

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.     

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