带刚性伸臂减震层高层结构抗震性能对比与分析

通过推导三角形形式钢管伸臂对有效层间位移的放大公式,得到了带刚性伸臂减震层高层结构中黏滞阻尼器的模态附加阻尼比计算公式.以一个框架-核心筒结构为例,对其分别设置刚性伸臂减震层、对角支撑减震层及加强层在近场脉冲波和非脉冲波作用下的抗震性能进行了对比与分析.结果表明,带刚性伸臂减震层高层结构的抗震性能在3类结构中最为优越,而脉冲波则会导致层间位移等性能指标大幅增加,设计时不容忽视.同时,带刚性伸臂减震高层结构抗震性能的提高与剪力墙到外框柱轴线间的距离成正比,与层高成反比,与阻尼器竖向夹角的余弦相关.     

风荷载下伸臂桁架-ATMD组合系统最优伸臂桁架位置研究

基于虚拟激励法和最优控制理论,提出伸臂桁架-主动调谐质量阻尼器(ATMD)组合系统的风振最优控制模型。首先推导伸臂桁架主体结构与ATMD耦合后的控制运动微分方程组并基于虚拟激励法求解该方程组,发展新的伸臂桁架-ATMD组合系统数值简化模型。基于新提出的组合系统数值简化模型,应用固定点理论求解ATMD最优控制力,获得伸臂桁架-ATMD组合系统的最优控制力模型。将新提出的伸臂桁架-ATMD组合系统数值简化模型和最优控制力模型进行有效数值组合,构建该组合系统的整体最优控制模型。将本文提出的基于固定点理论的最优控制模型与基于线性二次规划方法的最优控制模型、被动最优控制模型和无控制模型进行对比分析。最后应用基于固定点理论的最优控制模型对伸臂桁架-ATMD组合系统的最优伸臂桁架位置进行单参数敏感性分析,研究最优伸臂桁架位置对不同结构影响因素的敏感性以及ATMD对不同类型伸臂桁架系统的抗风控制效果。研究结果表明：主体结构伸臂桁架系统类型不同,不同控制方案的作用效果不同,且主动控制方案对加速度响应的控制效果优于对位移响应的控制效果;与纯伸臂桁架系统相比,风荷载作用下主动调谐质量阻尼器对组合系统的最优伸...     

一种新型的筒型粘弹性阻尼器

高分子阻尼材料在板壳结构中作为阻尼层布置,阻尼减振效果很好。利用这类阻尼材料设计并制成集中式阻尼器结构,便于应用到桁架类结构或建筑结构中去。本文介绍一种新型粘弹性阻尼器,包括：动力学建模、阻尼器动力学特性测试方法、结构设计和在实际桁架结构中应用的实验结果。     

基于自复位变摩擦阻尼器的结构减震控制

目的针对常摩擦力摩擦阻尼器不能根据结构反应实时调整滑动摩擦力、导致减振效果不稳定的问题,研发一种自复位变摩擦阻尼器.方法基于库仑摩擦定律建立自复位变摩擦阻尼器的恢复力模型,通过对设置以及未设置阻尼器的结构分别进行确定性及随机地震反应分析,研究该阻尼器的减振效果.结果确定性地震动作用下,自复位变摩擦阻尼器能够有效减小结构的层间位移反应,而绝对加速度反应通常有所增大;随机地震动作用下,自复位变摩擦阻尼器能明显减小无控时层间位移较大楼层的位移反应,多数楼层绝对加速度均方根值的均值和标准差有所减小,而楼层绝对加速度峰值大多增大.结论自复位变摩擦阻尼器能明显降低结构的位移反应,且位移控制效果基本上不随输入地震动加速度峰值的变化而改变,但受控结构的加速度反应通常较无控结构有一定增大.     

基于地震动特性的悬挂减振结构性能

分析了一栋已建悬挂建筑在不同地震动输入下的结构响应规律.首先,根据其特点,建立了相应的数值分析模型.其次,在3组远断层地震波和3组近断层地震波输入下,分析了地震动特性对悬挂结构减振效果的影响;最后,给出了阻尼器分布对减振效果的影响.分析结果表明:在远断层和近断层地震波作用下,存在最优的阻尼系数使得筒体的动力响应最小.虽然地震波频谱特性不同,但优化得到的最优阻尼系数差别不大.在近断层地震波作用下,主结构的动力响应较大,且减振效果相对较差.阻尼器连接悬挂楼面和主结构筒体时,能够较好地约束悬挂楼面的层间位移和相对于筒体的位移.近断层地震波作用下悬挂楼面的层间位移和相对于筒体位移比远断层地震波作用下大得多.当阻尼器的总量一定时,按三角形或悬挂楼面的基本振型布置阻尼器比均匀分布能取得更好的减振效果,且能够更好地抑制悬挂楼面的位移.     

粘滞阻尼器参数在连续梁桥地震反应中的响应分析

结合甘肃某高速公路一连续梁桥为背景建立Midas有限元分析模型,采用非线性动力时程分析法进行地震响应分析;在设置粘滞阻尼器后通过采用不同的阻尼系数组合工况对受到地震波作用的桥梁结构,对其墩底内力和梁端位移进行分析比对,得出论述当中实际桥梁工程案例设置粘滞阻尼器的最优阻尼系数,分析比较设置阻尼器前后的减振效果.结果表明,粘滞阻尼器在连续梁桥的抗震设计中有优越的性能,对梁端的位移、固定墩墩底剪力和固定墩墩底的弯矩明显减小;阻尼器的布置方案对桥梁抗震性能影响较为明显.     

单自由度结构的磁流变阻尼顶层隔振

提出了应用磁流变阻尼装置的顶层隔振控制方法．首先，对小质量比TMD的控制理论进行了深入研究，将最优TMD参数的计算公式推广到大质量比范围．以大质量比TMD控制的减振机理为基础，对顶层隔振结构的动力特性进行了研究，对参数影响进行了分析，建立了合理的顶层隔振结构体系；其次，引入磁流变阻尼器对顶层隔振结构的隔振层进行控制，避免TMD控制范围较窄和隔振层变形过大等弱点；最后，对单自由度结构进行了顶层隔振控制，理论分析结果证明：以大质量比TMD理论为基础的顶层隔振控制方法是有效的，结合了磁流变阻尼器的控制后可以避免这种方法的一些弱点，在不增加结构自重的前提下，能够保证结构良好的控制效果，隔振层的位移和结构层的加速度都得到较好的控制，控制效果达到30％左右，以磁流变阻尼器半主动控制效果最好。     

金属连梁阻尼器在高层剪力墙结构的设计方法

目的研究金属连梁阻尼器在高层剪力墙结构的设计,解决在高层剪力墙结构连梁中如何合理的布置金属阻尼器的问题.方法使用钢剪切型阻尼器对某高层剪力墙结构进行消能减震设计,从减震原理出发,展现阻尼器如何通过为结构提供更大的附加阻尼比和影响结构的主振周期,进而降低结构的水平地震影响系数,实现显著降低结构在地震作用下的反应的过程,并对消能减震结构进行经济技术分析.结果阻尼器的设置增大了单位工程造价,但可使结构在地震下使用功能连续,虽然略增大造价,但保证了建筑物的安全及功能;基底剪力可减小13%～42%,最大层间位移角可减小15%～47%,倾覆力矩可减小32%～52%,保障了人民的人身安全和财产安全.结论通过计算无控结构在多遇地震下的层间位移以及结构待布置连梁位置处的内力,确定阻尼器的设计屈服位移和屈服力,并将阻尼器均匀的布设在每一层可大大降低结构的地震反应,为工程人员进行类似的高层剪力墙消能减震设计提供了经验和参考;阻尼器的设置虽然导致造价略有增加,但可显著的降低结构各项指标在地震作用下的反应.     

核筒悬挂结构的动力特性及参数优化

基于欧拉伯努利梁理论和层剪切模型,应用拉格朗日方程推导了单段核筒悬挂减振控制结构的运动方程.在此基础上通过时程分析评价了结构的减振性能,应用复模态叠加法对结构的响应进行了频域分析,以主体核筒顶点位移和悬挂楼面层间位移响应为优化目标,对悬挂楼面的侧移刚度、阻尼器的刚度和阻尼系数进行优化.分析结果表明,存在最优的侧移刚度和阻尼器刚度使得核筒位移响应最小,存在较优的阻尼器阻尼系数可同时有效抑制核筒和悬挂楼面的响应,所以通过合理设置结构参数能够显著减小核筒悬挂减振结构的动力响应.     

高层建筑加强层粘滞阻尼系统的优化分析

提出了一种设加强层的框架-核心筒结构耗能减振系统,利用加强层与外围框架柱二者之间相对大的位移差,布设竖向粘滞阻尼器.基于结构简化计算简图,分别得到了采用假定振型法和有限单元法的数学模型.基于模态阻尼比,参数分析确定了阻尼器的最优阻尼系数.以一个安装了加强层阻尼系统的高层建筑为例,仿真分析了其在地震激励下的动力响应.研究表明,加强层阻尼系统可以大幅提高结构的模态阻尼比,有效减小结构的动力响应.     

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