各向异性抛物势对量子点中极化子基态结合能的影响

量子点中三个方向存在不同的抛物限制势,采用线性组合算符和幺正变换方法研究了各向异性抛物势对量子点中强耦合极化子的振动频率和基态结合能的影响.导出了振动频率和基态结合能随电子-声子耦合强度和量子点中的有效受限长度的变化关系.数值结果表明:振动频率和基态结合能是电子-声子耦合强度的增函数.它们随三个不同的有效受限长度的增加而迅速减少.表现出量子点在三个不同方向的新奇的量子尺寸限制效应.     

正切平方量子阱中的非线性光学折射率

从理论上研究了正切平方量子阱(QWs)在不同温度、流体静压作用下非线性光学折射率的变化.在有效质量近似的框架下,通过求解薛定谔方程得到本征函数和能量本征值.利用密度矩阵理论和迭代方法,得到了非线性光学折射率变化(RIC)的解析表达式.计算结果表明,流体静压、温度、电势和QWs的直径对RIC有很大的影响,所得结果可以为研究正切平方量子阱的光学折射率变化提供必要的理论依据.     

抛物型量子点的非线性光学整流研究

在紧凑密度矩阵方法和迭代法的框架下,从理论上研究了抛物型量子点(QDs)在不同的量子点半径、宽度以及外加电场和磁场下光学整流(OR)系数.在有效质量近似下,计算了量子点中电子的受限波函数和能量.给出了典型GaAs/AlGaAs抛物型量子点的数值结果.通过研究发现,非线性光学整流系数受到量子点的宽度、半径以及电场和磁场的...     

倾斜磁场中各向异性抛物量子盘的光吸收特性

从理论上研究了倾斜磁场中具有各向异性抛物量子盘的光吸收特性。利用有效质量近似,通过求解量子盘的哈密顿量,得到了量子盘的能级,通过使用密度矩阵理论和迭代法,给出了系统的总光吸收系数。结果表明系统沿x方向上受限势频率ω_x、参数η以及磁场倾角θ的变化均会对量子盘的光吸收系数产生明显影响。此外,在一定范围内当受限势频率ω_x、磁场倾角θ增大时,总光吸收系数的共振峰位置会向入射光子能量高的区域移动。     

斜磁场作用下抛物量子点的折射率系数变化规律研究

本文首先使用有效质量近似的方法研究了在斜磁场作用下各向异性抛物量子点系统,并求得了系统的能级与波函数。然后运用密度矩阵与迭代的方法得到系统的线性、非线性以及总的折射率改变的表达式,使用典型的GaAs材料来进行数值计算。计算结果表明,磁场的倾斜角度以及系统参数对于总的折射率系数的改变有较大的影响,随着磁场倾斜角度的增加,总的光折射率系数改变的峰值却在减少,并且向着高能量方向移动;然而随着系统结构参数的增加,总的光折射率系数改变却在不断的增加。     

非对称量子点中束缚磁极化子的跃迁频率

在磁场和库仑场作用下,采用线性组合算符法计算了非对称量子点中极化子的跃迁频率.计算结论:跃迁频率不仅与磁场回旋频率有关,还与横向和纵向有效受限长度、极化子的振动频率、库仑束缚势、电子-声子耦合强度有关.研究结果表明:极化子的跃迁频率分别是磁场回旋频率、库仑束缚势、极化子的振动频率、电子-声子耦合强度的增函数;是横向和纵向有效受限长度的减函数,说明量子尺寸效应较显著.     

半抛物量子阱中二阶非线性光学性质的研究

本文对外加电场作用下GaAs/AlGaAs半抛物量子阱非线性光整流和二次谐波极化率进行了研究.首先,本文运用密度矩阵和迭代的方法获得外加电场作用半抛物量子阱系统光整流和二次谐波极化率的表达式.同时,采用有限差分法求得多外加电场作用下该系统的能级和波函数,避免了精确求解过程中的多重不恰当近似.结果表明:1)有限差分法计算结果相当精确;2)外加电场和受限势频率与系统能级、受限势形状、以及光整流和二次谐波极化率有着密切的关系,同时,可以通过外加电场和受限势频率实现对该系统光整流和二次谐波极化率的有效调控.将为基于子带跃迁的光电子器件的制备提供理论基础.     

高斯光束经非线性指数型发散梯度折射率棒透镜的成像公式

用抛物函数近似非线性指数型折射率的线性部分，导出高斯光束经非线性指数型发散梯度折射率棒透镜的成像公式。几何光学条件近似下得到的简化成像公式与几何光学理论得到的精确解比较，误差很小。     

轴向磁场中电弧的螺旋不稳定性

讨论了抛物形电导率、线性热势电导率、正态分布电导率以及抛物形透明辐射模型下，轴向磁场中电弧的螺旋不稳定性。将所得结果与均匀电流分布情形作比较，稳定区域变大，与实验结果相符。     

各向异性抛物势对量子点中强耦合极化子激发态的影响

在各向异性抛物势限制下,采用Huybrechts线性组合算符和Lee-Low-Pines(LLP)幺正变换方法研究了量子点中强耦合极化子激发态的性质.导出了极化子第一激发态振动频率和第一激发态能量随电子-声子耦合强度和各向异性抛物势在量子点三个方向上的有效受限长度的变化关系.数值结果表明:第一激发态振动频率和第一激发态能量是电子-声子耦合强度的增函数且它们均随有效受限长度的增加而迅速减少,表现出量子点新奇的量子尺寸限制效应.     

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