180°铁电畴夹层结构中的畴层波

从压电方程出发,讨论了180°畴夹层结构中的铁电畴层波特性,得到了对称和反对称两种振动模,并给出了色散关系及波场的空间分布,认为反对称振动模为另一种新的铁电畴层振动模,并讨论了双层等厚180°畴结构的情况,得到具有新特点的反对称铁电畴层振动模.     

双层压电板的180°畴中传播的SH型电声表面波研究

本文从一般的压电方程出发,给出了在双层压电板的180°畴中传播的SH型电声表面波波解,着重讨论了两层的厚度相等时的情况,并给出了其色散关系及波场的空间分布.理论分析和实验测试均表明等厚双层压电板与铁电畴层波波导具有相似的传输特性,且更有利于低频信号的传输.     

不同压电陶瓷中的铁电畴层波

本文对SH型压电表面波在由不同压电陶瓷组成的180°畴层结构中的传播问题进行了讨论,通过理论分析和数值计算得出了铁电畴层波在此结构中传播时的存在条件和色散关系.文中给出了铁电畴层波的一般化存在条件.研究结果表明,层状结构中除了Love型波外,还能传播另一类SH型表面波,即铁电畴层波.     

畴层波的色散性质

本文通过理论计算,分析了畴层界面振荡对畴层波的作用.计算得出了不同条件下界面振荡对所在界面的表面波的色散关系影响的结果.     

偶数维空间中黏性波方程解的逐点估计

考虑偶数维空间中黏性波方程柯西问题解的逐点估计.黏性波方程是流体力学中重要的数学模型,它既有波的传播特性,又受黏性项的影响.利用格林函数的方法:首先,对柯西问题的基本解即格林函数施以Fourier变换;其次,用光滑截断函数将格林函数的Fourier变换分成低频、中频和高频3个部分分别讨论;再次,利用Fourier逆变换的性质得到格林函数的逐点估计;最后结合Duhamel’s原理得到解的逐点估计.柯西问题的解呈现出广义惠更斯原理.     

有限多层180°铁电畴中界面波的色散特性

从克利斯托夫方程出发,通过数值计算,对PZT-有限多层180°铁电畴结构中的界面波的色散特性进行了理论探讨.指出偶层数结构基模类似于铁电畴层弯曲波,奇层数结构基模类似于铁电畴层波,并与其他一些情况下的结果进行了比较,最后通过实验验证了部分理论结果.     

材料常数对铁电畴层波色散特性的影响

考虑到铁电畴层波色散方程的复杂性，通过分析其色散曲线的特点，在大量数值计算的基础上，讨论了传播介质的材料常数对铁电畴层波色散特性的影响，找出了传播介质的材料常数对铁电畴层波相速度极小值ｖｍｉｎ及与之相对应的频率因子ｋｈ的影响规律，为铁电畴层波的实际应用提供了理论基础．     

高铁地震波场特点的理论分析

为了利用高铁震源反演浅层或深层地下结构, 将高铁铁路桥墩视为点源位置, 分别利用波阵面叠加、求解声波波场和半无限空间弹性波波场等方法, 对高铁激发的远场波场进行模拟。利用不同类型的震源时间函数与格林函数卷积计算得到的波场结果显示, 考虑高铁自重影响的桥墩静力响应的低频震源时间函数对应的波场与实际记录具有一定的相似性。     

移动通信在树林中的电波传播特性

对发射机位于一个 4层树林模型中的树冠层 ,而接收机位于树干层的移动通信进行了研究。首先利用并矢格林函数推导出了问题的积分表达式 ,然后利用准静态法、鞍点法以及支点切割法得到了接收场的求和表达式。当发射机和接收机之间的水平距离增加到一定量时 ,沿空气 树冠界面的侧面波在总场中占主导地位 ,而在这之前透射波和多次反射波在总场中占主导地位。还给出不同工作频率和不同水平距离情况下的传输损耗的计算结果     

用并矢格林函数方法求解四层丛林模型的场:Ⅱ应用部分(英文)

本文用矢格林函数方法求解了在四层丛林模型中任意极化的电偶极子的电磁场。给出了侧面波决定的远区场及使该场有最大激励的偶极子的最大入射角。     

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     

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