表层正交异性材料夹层板弯曲平衡方程及边界条件

分别根据夹层板的Ｒｅｉｓｓｎｅｒ理论和Ｈｏｆｆ理论,推导出表层为正交各异性材料夹层板的弯曲平衡微分方程,方程中包括ψｘψｙω三个广义位移。     

空腹夹层板的构造及连续化分析方法

空腹夹层板是一种的楼盖体系，有良好的力学性能及技术经济指标。本文介绍了空腹夹层板楼盖的构造及特点。采用Ｒｅｉｓｓｎｅｒ型夹层板理论，导出了空腹夹层板连续化的六阶偏生分方程式，给出了矩形平面周边简支条件下微分方程的解析解，并作了算例分析。     

变厚度夹层板的弯曲问题

以三个广义位移和夹芯厚度为基本变量,以 Ｒｅｉｓｓｎｅｒ 理论的基本假设为基础,建立了夹芯层厚度沿一个方向线性变化的三层夹层板弯曲问题的偏微分方程当令 ＝ ０ 时,方程便退化为经典的等厚度夹层板的平衡偏微分方程     

变厚度夹层板的弯曲问题

以三个广义位移和夹芯层厚度为基本变量,以Ｒｅｉｓｓｎｅｒ理论的基本假设为基础,建立了夹芯层厚度沿一个方向线性变化的三层夹层板弯曲问题的偏微分方程。当令φ＝０时,方程便退化为经典的等厚度夹层板的平衡偏微分方程。     

夹层矩形板的非线性动力屈曲

研究了夹层矩形板的非线性动力屈曲问题,基于Ｒｅｉｓｓｎｅｒ假设和Ｈａｍｉｌｔｏｎ原理下的夹层矩形板的非线性运动控制方程,应用伽辽金方法和双金参数摄动法确定四边简支夹层矩形板在纵向简谐载作用下的非线性动力不稳定区的边界,并对影响动力稳定性的若干因素进行探讨。     

新型CSIPs复合夹层板的力学性能研究

结合玻璃纤维增强复合材料(Fiber Reinforced Polymer,即FRP)和SIPs板(Structural Insulated Panels)的优点,提出了一种以FRP作为面板,扩展聚乙烯泡沫(EPS)为芯板的CSIPs复合夹层板.为了掌握CSIPs复合夹层板的力学性能,首先采用Reissener大挠度理论,推导了CSIPs复合夹层板的挠度和极限承载力的计算公式;然后应用ANSYS软件进行了有限元模拟分析;最后制作1 000 mm*1 000mm的CSIPs复合夹层板进行了模型试验研究.结果表明,理论分析解、有限元模拟结果和试验结果三者基本一致,根据大挠度理论推导出的CSIPs复合夹层板的位移及极限承载力正确;CSIPs复合夹层板重量轻、强度高的优点突出.     

矩形夹层板的非线性弯曲问题

本文将非线性弯曲的理论引入夹层板的表板,在考虑表板抗弯刚度情况下导出了矩形夹层板非线性弯曲的基本方程,并进一步求解了四边固支的矩形夹层板的大挠度问题,所得结果的线性项部分与文献(2)的线性理论的计算结果基本相同。本文并讨论了线性理论适用的范围。本文的公式便于工程应用。     

四边简支条件下对称蜂窝夹层板的弯曲振动分析

应用经典叠层板理论(CPT)、一阶剪切板理论(FSDPT)和三阶剪切板理论(TSDPT)对四边简支条件下对称蜂窝夹层板的弯曲振动进行了分析.弯曲振动分析中将蜂窝芯层等效为一正交异性层,其等效弹性参数由修正后的Gibson公式获得,推导了蜂窝夹层板在四边简支条件下的固有频率方程.经具体算例表明,对于铝蜂窝夹层板固有频率的计算,三阶剪切板理论的计算精度要高于经典叠层板理论和一阶剪切板理论.     

试析交流电路功率的教学内容处理

在讲授交流电路的功率时，要注意分清内容的重点和难易程度，使学生从道理上弄懂，从根本上解决问题。设某一交流电路两端的瞬时电流和瞬时电压为：ｉ＝Ｉｍｓｉｎｗｔ（１）ｕ＝Ｕｍｓｉｎ（ｗｔ＋ψ）（２）电路的瞬时功率为ｐ瞬＝ｕｉ＝Ｕｍｓｉｎ（ｗｔ＋ψ）·Ｉｍｓｉｎｗｔ＝ＵｍＩｍｓｉｎ（ｗｔ＋ψ）ｓｉｎｗｔ＝２ＵＩｃｏｓψｓｉｎ２ｗｔ＋ＵＩｓｉｎψｓｉｎ２ｗｔ（３）（３）式中右边第一项的变化规律与电阻的瞬时功率的变化规律相同，只是多了一个系数ｃｏｓψ。如果电路中只有电阻原件，ψ＝０　ｃｏｓψ＝１　ｓｉｎψ＝…     

芯板垂向可压缩夹层板有限元建模及声辐射性能分析

针对以往夹层板理论大多忽略芯板的垂向应变这一不足,构造了一种考虑芯板垂向可压缩变形的夹层板位移模式,并推导了相应的有限元单元及控制方程,求解了夹层板动力响应,进而利用有限元结果通过边界元法求解了一定频率范围内的夹层板声辐射功率,分析了芯板几何物理参数对夹层板声辐射性能的影响.结果表明,考虑芯板垂向可压缩变形在夹层板声辐射性能研究中是合理的,也是必要的;在一定范围内增加芯板厚度、降低其弹性模量均可减小夹层板单点简谐激励下的声辐射水平.     

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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