粘弹性正交各向异性对称层合板的非线性动力响应

分析了几何非线性粘弹性正交各向异性对称层合矩形板的非线性动力响应问题。由Kirchhoff假设，Boltzmann算子和Kaman方程，在假设poisson比为常数的条件下，推导了粘弹性正交各向异性对称层合板的非线性动力方程，该方程为一非线性偏微分，积分方程组，经无量纲化和应用Galerkin方法之后，得到关于时间变量的非线性微分，积分型的方程，以三层(单层各向同性)对称矩形层合板作为特例进行数值计算，得到不同材料性质对频谱曲线以及时间，位移曲线的影响，当退化为各向同性粘弹性薄板时，其计算结果与文[1]的一致。     

含热传导效应粘弹性板耦合非线性动力分析模型

基于薄板大挠度Karman理论和用Boltzmann叠加原理描述的粘弹性材料本构方程、动力学平衡方程和热粘弹能量原理建立了横向周期荷载、面内均布荷载和温度场作用下,考虑热传导效应的粘弹性矩形板的热机耦合非线性动力学模型,并用Galerkin方法将该热机耦合非线性动力学模型转化为非线性微分．积分动力系统．且该热机耦合非线性动力学模型可以退化为粘弹性板动力学模型、仅含热膨胀效应粘弹性板动力学模型和热机耦合弹性板动力学模型．     

屈曲粘弹性倾斜矩形板的非线性振动分岔

粘弹性矩形板在工程中经常发生各种振动，根据屈曲粘弹性倾斜矩形板的非线性动力方程，采用Melnikov法及Galerkin原理研究了其在铅垂周期扰力作用下的非线性振动分岔。并讨论分析了倾斜角、长宽比、板厚等因素对屈曲粘弹性矩形板发生混沌运动区域的影响，得到了倾斜角、板厚的增加会使混沌运动区域减小，长宽比的增大会使混沌运动区域变大的重要结论。     

非线性粘弹性桩的横向混沌运动

研究了轴向周期载荷作用下非线性粘弹性嵌岩桩的横向混沌运动．假定桩和土体分别满足Leaderman非线性粘弹性和线性粘弹性本构关系,得到的运动方程为非线性偏微分．积分方程;利用Galerkin方法将方程简化为非线性常微分方程,并进行了数值计算;考察了几个参数的影响．数值结果表明非线性粘弹性桩可以通过准周期分叉方式进入混沌运动状态．     

粘弹性索非线性响应及动力稳定性

根据Ｒｅｖｌｏｎ材料的一维本构方程及索的运动方程导出了粘弹性索在重力作用下,面内和面外的偏微分运动方程。利用Ｇａｌｅｒｋｉｎ方法将偏微分方程转化为一组非线性常微分方程。给出了粘弹性索的动力稳定性分析方法。通过数值仿真研究说明了弹性和粘性参数对索的动态响应的影响。     

一类非线性粘弹性梁的动力学模型及其简化

建立了描述均匀粘弹性梁动力学行为的偏微分－－积分方程，梁的材料满足Ｌｅａｄｅｒｍａｎ非线性本构关系，对于两端简支的情形用Ｇａｌｅｒｋｉｎ方法进行了截断简化为常微分－－积分方程，地于特定材料进一步简化为常微分方程。     

粘弹性基础上粘弹矩形板的非线性振动响应分析

采用多重尺度法,利用Ｍａｔｈｅｍａｔｉｃａ符号推导,求解了粘弹性基础上粘弹矩形板的非线性振动问题,并系统地分析了主共振情况,得到了二阶近似解的骨干曲线。     

粘弹性曲梁的动力稳定性

利用线性粘弹性力学中的微分型本构关系,建立了粘弹性Timoshenko曲梁在均布随从力作用下的屈曲运动微分方程。分离屈曲位移中的空间变量和时间变量,采用归一化幂级数法建立起该非保守系统的复特征方程,在考察位移单值性条件的基础上,运用拟牛顿法得出粘弹性曲梁振动参数随随从力的变化关系曲线,研究了支承条件对粘弹性曲梁非线性动力稳定性的影响,并考察了材料粘性对结构动力稳定性的影响。     

沥青混合料力学特性和研究方法

沥青混合料是高等级道路路面的主要建筑材料，多年来的研究表明其是一种复杂的热流变材料。其变形与受力状态．温度及加载速率等多种因素有关。其具有明显的各向异性、不均质、甚至不连续性，因此它具有复杂的非线性性质。沥青混合料在受载情况下常常表现出明显的非线性粘弹性性质，过去对于其进行力学分析的研究往往局限于线粘弹性，使其优良的力学性能得不到充分的发挥。粘弹性理论是在力学和材料之间发展起来的边缘科学，是连续介质力学的一个重要组成部分。目前，国内外学者在粘弹性理论研究领域取得了许多重要的研究进展，线粘弹性理论已发展得较为完善，非线性粘弹性理论由于实验和数学上存在的困难尚处于不断的发展和完善之中。     

亚音速气流下不对称双跨粘弹性板的非线性振动特性研究

研究了亚音速气流作用下不对称双跨粘弹性板的非线性振动特性。考虑von Kármán几何大变形, 利用Hamilton原理,建立了不对称双跨粘弹性板的非线性运动方程, 并对其采用分离变量法进行了离散, 运用线性势理论得到了亚音速气流的气动压力表达式, 利用板的边界条件和中间支承条件得到了双跨板的模态函数。研究了来流速度对双跨板非线性振动特性的影响, 分析了不对称程度和粘弹性阻尼系数对结构发生混沌运动的影响。     

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.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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

正~~