差压式电容传感器膜片的变形分析与优化设计

为研究差压式电容传感器测量膜片的受压变形，将经典的von Kármán薄板理论应用于受有预张力作用的弹性圆薄板问题，采用同伦分析法给出近似解析解.将求解结果与有限元软件ANSYS的仿真结果进行对比，表明两者吻合度较高.预张力大小对膜片在受压情况下的变形影响较大，从而影响传感器的电容输出特性.利用传感器性能测试验证了预张力对传感器非线性特性的影响.结果表明：选择合适的预张力可以有效提升传感器的线性度，适当降低膜片厚度可以提高输出的灵敏度.分析结果对差压式电容传感器的膜片设计具有重要的参考价值.     

边界条件对附于软基体上压电薄膜的局部屈曲的影响

本文研究了附于预拉伸弹性软基体上的压电薄膜的局部屈曲行为,弹性软基体和刚性支座之间为滑动边界。通过比较弹性软基体和刚性支座之间为固支情况下附于基体上压电薄膜的局部屈曲行为,讨论边界条件对于压电薄膜的局部屈曲的影响。     

考虑界面应力时含椭圆孔正交异性材料的反平面问题研究

研究了远场作用反平面剪切载荷时含纳米椭圆孔正交异性材料问题。基于Gurtin-Murdoch表面/界面理论模型引入界面应力,利用复变弹性理论和保角映射方法,给出了考虑界面应力时含椭圆孔正交异性材料反平面问题的解析解答,获得了应力场的闭合解。研究表明:当椭圆孔在纳米量级时,正交异性材料内应力场受孔隙尺寸影响显著。随着椭圆孔尺寸的增大,界面效应对应力场的影响逐渐减弱,趋近于经典弹性理论的解答。界面效应对正交异性材料内应力场的影响随着材料弹性主方向比55/44的增大逐渐减弱。     

压电效应对软基体上压电薄膜局部和整体屈曲的影响

附于预拉伸软基体上的弹性薄膜会发生局部屈曲,将这一特性应用于微纳米系统,可以发明新的可延展性电子器件.通过变分法推导了压电薄膜/软弹性基板复合系统的控制方程,分析了基体预拉伸情况下的压电薄膜/基体复合系统的整体屈曲机制.进一步研究了局部屈曲和整体屈曲的转换现象,得到了2种屈曲模式临界条件的解析解.结果发现,薄膜材料的压电效应对整体屈曲和局部屈曲2种屈曲模式的临界条件都具有不可忽略的影响,压电薄膜系统比弹性薄膜系统具有更高的刚度和更好的稳定性.     

基于ABAQUS的各向异性复合材料梁的分析研究

基于大型有限元著名软件ABAQUS,对复合材料梁有限元分析进行了研究.以承受均布荷载的悬臂梁作为实例进行分析,根据Lekhniskii的各向异性弹性理论应力解答,推导得出梁弯曲轴线的方程,然后把有限元数值计算结果与各向异性弹性理论解答对比分析,验证ABAQUS对复合材料梁建模分析的正确性,并讨论材料各向异性、材料弹性主轴方向以及高跨比对结果的影响.     

弹性地基上对称正交铺设层合板的受迫振动

研究置于弹性地基上受到面向预加荷载的对称正交铺设层合板在受到冲击荷载作用时的动力响应，根据高阶剪切变形理论推导出由位移表示的运动方程，用模态叠加法解得振动频率及动力响应，把所得的结果与一阶剪切变形理论做了比较，并讨论了材料、几何参数、地基刚度系数对动力响应的影响。     

弹性基础上预应力中厚矩形板的横向振动

基于Reddy高阶剪切板理论，研究预加均匀温度场和面内机械荷载作用下，双参数弹性基础上各同同性中厚矩形板的振动特性，给出了确定板振动频率的半解析数值方法，通过算例考察了温度变化，面内荷载、基础刚度参数、边界条件、横向剪切变形等对板振动特性的影响，结果表明，温度升高与预加面内压力将使板的自振频率下降，而增加基础刚度和预加面内拉力则有助于提高板的自振频率。     

有限深地基表面在环形均布荷载作用下的沉陷计算

本文提出了完全粘合于刚性下卧层上的有限深弹性层地基表面环形面积上作用均匀分布荷载时的沉陷计算公式,并对各种层厚比情况下地基沉陷系数算出了数值结果。这些结果可以直接应用于基础圆板的计算。本文又一次从理论上证明了,对于空间问题,半无限地基和文克勒地基都是有限深弹性层地基的特殊情况。     

位错与纳米裂纹干涉的反平面问题

针对位错与纳米裂纹干涉的反平面问题,提出了一种新方法,得出了精确解.首先利用复变函数中的保角变换方法,将直线裂纹问题化为孔板问题,再借助于柯西积分,获得了该问题的精确解答,然后分别推导出有、无表面效应作用时的应力场和位错力的解析表达式.数值结果表明:当裂纹尺寸缩减到纳米量级时,表面效应的影响使裂纹尖端附近的应力场和位错力减小,但随着裂纹长度的增大,表面效应的影响能力逐渐减弱,含表面效应的解答逐渐趋近于无表面效应的经典弹性理论解答.     

带有周期性裂纹薄膜热弹性场模拟研究

通过建立带有周期性裂纹缆索薄膜/基底二维平面模型,分析不同参数对薄膜热弹性场的影响。运用有限元软件分析了在温度荷载作用下不同薄膜/基底弹性模量比、热膨胀系数对薄膜位移场、应力场的影响并且与理论值进行对比。结果表明有限元模拟结果与理论预测结果吻合良好,以上因素变化对薄膜轴向位移、轴向应力有明显的影响。薄膜表面位移和拉应力随着薄膜/基底弹性模量比与薄膜热膨胀系数的增大而增大,基底会对薄膜的热弹性场起到限制作用,边缘效应也会对薄膜热弹性场起到影响。理论值在薄膜与基底弹性失配较小或在薄膜边缘处不能准确的预测实际值。     

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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