高层框架自由振动的Sturm-Liouville微分方程

提出一个计算高层框架基本周期的简单方法.为简化计算,用一个等直弯-剪悬臂梁来模拟高层框架结构进行动力分析.证明了高层框架自由振动的微分方程是四阶Sturm-Liouville微分方程,用变分法推导出计算高层框架自由振动基本周期的表达式.     

水平荷载作用下空腹巨型框架受力性能研究

根据截面惯性矩相等的原则,推导了空腹巨型框架等效截面高度系数以及材料用量比。以12层巨型框架为例．对比计算了实腹结构与空腹结构的自振周期、振型及位移、内力,并探讨了刚域与次框架对结构受力性能的影响。结果表明．空腹巨型框架结构自振周期较小,抗侧移刚度提高,侧移较小,且抗侧移刚度、侧移与内力突变较小,有利于增加使用空间,节省材料：刚域使得结构自振周期减小,侧移减小,次框架的存在大幅度地减少了结构侧移。     

典型框架结构的振动分析与减振控制处理

某化肥厂苯菲尔车间框架结构在正常生产中存在大幅低频振动.利用计算软件对框架建立有限元分析模型并进行模态计算,确定其周期与振型,查清大幅低频振荡的机理.同时,采用在主要动力源所在位置处加设钢支撑,以增加苯菲尔框架沿动力作用方向的刚度,使苯菲尔车间框架的振荡幅值降低到允许的限值,解决了苯菲尔车间框架振荡的工程问题.     

基于ANSYS的巨型框架结构体系地震响应分析

文章采用有限元软件ANSYS自带的APDL语言进行参数化三维结构建模,对巨型框架结构进行抗震性能计算分析,包括模态分析、谱分析及时程分析,讨论了不同主次框架刚度比下巨型框架结构的动力特性及地震响应.结果表明:钢筋混凝土巨型框架在地震作用下的侧移曲线为弯剪型;主次框架刚度比对巨型框架弹性地震反应影响较大;当结构高阶频率对...     

地震载荷作用下高层框架结构振动分析

利用ANSYS有限元软件对框架结构建立有限元模型并进行模态计算,确定其固有频率、周期和振型。计算了高层框架结构在地震载荷作用下的响应,并绘出结构各层节点x、Y和z方向位移时程曲线,为进一步振动控制提供理论参考。     

高烈度设防区多层框架结构的抗扭设计

以8度区某5层框架结构为例,探讨第一周期比及第一、二主振型对扭转效应的影响.通过调整第一周期比和对第一、二主振型提出相应限制,避免引起平面振动与扭转振动的耦合反应,降低结构破坏的几率.采用空间有限元软件SATWE等手段对该框架建立多个实体模型,并进行整体对比分析,提出了该工程较理想的结构抗扭设计方案.     

构架式基础的动力计算

为解决高转速、大功率回转机械的构架式基础的动力计算，在ＴＱ－１６型计算机上编制了计算程序。本文对此做了简单介绍。基础视作空间团聚质量系统。质量矩阵可以按不同的要求灵活地进行约化。故水平振动与铅垂振动可以方便地分别计算，亦可同时计算。计算对称结构特别迅速简便。可以考虑节点刚性区的影响。应用“迁移子空间迭代法”——它将通常的子空间迭代与施米特正交手段结合起来，以计算一定转速范围内的全部自振频率与振型。最后，利用这些振型通过振型迭加法计算阻尼强迫振动的振幅与动内力。     

基于ANSYS的多层框架结构模态分析

利用大型有限元软件ANSYS对11层框架结构进行了模态分析,分别计算了不同情况下纯框架体系和框架—填充墙体系结构自振周期,分析了不同因素对框架结构周期折减系数的影响。     

碟式分离机"转鼓-转轴-支承"系统的振动研究

全面推导了“转鼓-转轴-支承“系统的系统振动方程、转轴弯曲振动微分方程及其简化方程、主振型方程和频率方程,给出了某型号分离机前三阶临界转速与主振型的计算结果,讨论了临界转速的影响因素.文章最后给出了系统共振转速的测试结论和测得的分离机振动频谱图.     

框架结构考虑填充墙共同作用的抗震性能有限元分析

针对填充墙体具有一定抵抗变形的能力且对框架主体的抗震能力存在一定程度影响,采用SAP2000软件建模与计算平台,分别创建了未设置填充墙体的纯框架模型和设置了填充墙体的框架模型,对模型进行模态和振型反应谱分析来计算研究由于填充墙体的存在对于框架结构的自振周期、层间位移角和层间剪力等结构固有性质、变形以及内力响应方面的影响。结果表明:四周设置了墙体的框架结构受地震作用的影响相对较小,抵抗地震作用的能力相应提高。     

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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