建模方式对T型桥梁地震反应的影响研究

研究了不同的建模方式对不同的墩高、不同场地条件下桥梁地震反应的影响程度。研究发现：无论在何种场地条件、何种桥墩高度的桥梁,单梁模型在纵、横桥向地震响应的分析精度都较高,能满足工程设计需要;梁格模型纵向地震响应分析误差在5％以内,横向地震响应分析误差在10％-20％。因此,对于横向由多片梁组成的T梁桥,单梁模型建模简单且精度较高,能满足工程设计需要。     

梁格法在变宽异型箱梁桥设计中的应用

基于剪力-柔性梁格法的基本原理,建立变宽异型箱梁结构的有限元模型,得到全桥纵向和横向的内力分布情况,并建立单梁模型与梁格模型进行应力计算结果的对比。结果表明:梁格模型简单易行、精度高,可满足工程设计的要求,可用于变宽异型箱梁结构的设计。     

城际铁路变宽度连续箱梁桥的动力特性

研究了变宽度连续箱梁桥在成桥状态下的动力特性.以某五跨变宽度连续箱梁桥为背景,建立整桥三维空间有限元模型,对大桥的模态进行分析,并选用50年超越概率分别为3%(E1)和10%(E2)两个水准的反应谱进行成桥阶段的地震响应分析.结果表明:E1,E2概率下,变宽度连续箱梁桥制动墩上的内力较大,且顺桥向地震荷载作用对制动墩的内力影响比横桥向地震荷载作用大,竖向地震荷载作用对桥墩轴力影响较大,而对桥梁上部结构位移影响不大,变宽度连续箱梁桥地震反应随桥墩高度增加而增强.建议桥梁设计时,重点考虑固定墩及固定支座的设计,并对固定墩底部进行加固处理,抗震分析时,慎重考虑地震荷载竖向分量取值.通过地震反应谱分析,在规范要求的地震荷载作用下,变宽度连续箱梁桥整体抗震性能良好,满足抗震设计要求.     

非径向支承弯梁桥荷载横向分布的简化计算

用刚性横梁法计算非径向支承弯梁桥的荷载横向分布 ,在计算单梁挠度时考虑了主梁梁端非径向支承的影响 ,得到了更为精确的结果 ,根据影响参数 ,编制了相应的表格 ,方便工程设计人员查用 .同时 ,还得到了此类桥梁的一个重要性质———转动中心的轨迹 .     

单梁模型在斜交连续梁桥荷载试验计算中的适用范围

介绍了桥梁荷载试验计算的常用方法,采用梁格模型和单梁模型分别对不同跨宽比和斜交角的等跨连续梁桥进行计算,分析梁格模型和单梁模型的内力、位移在不同跨宽比和斜交角情况下的变化规律.为等跨连续梁桥荷载试验的计算模型选择提供参考.     

剪力——柔性梁格法在RM2006中的应用

利用国际知名有限元软件RM2006对某座小半径曲线箱梁桥分别采用单梁模型及空间梁格模型进行分析比较,结果表明使用RM2006依据剪力-柔性梁格理论建立空间梁格模型简单易行,分析的精度能满足工程设计的要求。     

连续斜交梁桥地震下碰撞效应分析

从连续斜交梁桥震后普遍的落梁震害和平面旋转现象出发,提出一种带碰撞单元并考虑竖向、水平及扭转刚度的单梁简化模型.以一座3m×30m连续斜交梁桥为工程背景,通过动力特性分析和地震下考虑碰撞效应的非线性时程分析,将简化模型的计算结果与精细化板单元有限元模型的结果进行对比.研究结果表明:该简化模型不仅能较准确地计算结构的动力特性,还能较准确计算斜交梁桥在碰撞下的非线性位移,反应碰撞后桥面的平面旋转现象;碰撞刚度在一定范围内对非线性位移不敏感,可采用主梁轴向刚度为碰撞刚度,但梁端截面最外缘的碰撞单元对非线性位移较敏感,需保证在梁端截面最外缘处设置碰撞单元.     

大跨度斜拉桥拉索分段模拟对动力特性的影响

为反映斜拉桥拉索本身和桥梁的相互耦合的动力特性,将单根拉索用多根索单元分段精细模拟,考虑拉索本身振动对传统的单梁式斜拉桥的整体动力特性计算结果的影响,同时还提出一个考虑拉索分段但忽略拉索本身振动的分析模型,并对三种模型的分析结果进行了比较,最后用一个风洞试验的气弹模型对动力特性进行了校核.     

考虑随机变量相关性的桥梁地震易损性分析

引入Nataf变换,结合均匀设计响应面法,提出了一种综合考虑地震动和结构不确定性及结构参数相关性的桥梁地震易损性分析方法.以一多跨连续梁桥为研究对象,分别对算例桥梁在考虑与不考虑结构参数相关性情况下进行了地震易损性分析.同时,分析了考虑结构参数变量相关性对结构易损性分析和响应面模型精度的影响.结果表明:本文方法可以有效考虑结构参数之间的相关性,且考虑变量相关性后建立的响应面能够更好地拟合结构真实的极限状态函数曲面;桥梁结构在各个破坏状态下的失效概率均有一定程度的降低;忽略结构参数相关性的影响,可能会低估桥梁结构在地震作用下的抗震性能.     

考虑弦杆约束的新型板桁加劲梁扭转变形计算方法

针对某拟建千米级跨度高速铁路悬索桥所采用的新型板桁加劲梁,依据剪切刚度等效原则,构建闭口薄壁箱形梁连续化等效模型;基于截面刚性周边假定,考虑弦杆纵向约束作用,建立连续化等效模型的扭转平衡微分方程,推导得到扭转角解析公式。构建悬索桥连续化等效单梁有限元模型,推导悬索桥加劲梁扭转角解析式。通过算例验证该解析公式计算所得加劲梁扭转角与空间精细化有限元计算结果吻合良好,弦杆纵向约束作用对新型板桁加劲梁扭转变形影响不可忽略。研究结果表明：相比于空间精细化有限元模型,连续化等效单梁模型计算所得悬索桥加劲梁挠度和扭转角最大相对误差分别为1.8%和14.7%,依据解析式计算所得相对误差分别为7.1%和6.3%;对于悬索桥加劲梁扭转刚度初步设计,上述2种方法的精度误差均在可接受范围内,且计算效率大幅提高,具有较好的适用性。     

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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-