深亚波长二维光栅研究的新方法——等效介质层法

采用耦合波理论对结构尺寸远小于波长的二维亚波长周期光栅进行讨论。结果表明,这种二维亚波长周期光栅可等效为一介质层,这种介质层具有双折射晶体的性质,文中给出了相应的等效折射率。     

可见光波段亚波长防伪光栅的实验研究

研究可见光波段亚波长防伪光栅的制做.给出了用2θ夹角一次光刻、2θ夹角摆动δ角两次光刻和2θ夹角旋转β角两次光刻等干涉光刻工艺设计和构建可见光波段亚波长光栅微结构的基本原理.优化设计的干板表面曝光量分布函数可用于构建特定面形分布的光栅微结构.制作了可见光波段的1维和2维亚波长光栅微结构,给出了其SEM和AFM实验数据和理论分析图形,检验了微结构的彩色防伪光变效果.实验结果表明:该干涉光刻工艺能够构建出表面光滑、深度较大的复杂光栅微结构,并能展现出一定的彩色光变效果.     

亚波长结构抗反射表面的设计方法

对亚波长结构抗反射表面的设计原理和设计方法进行了较详细的论述.基于等效媒质近似理论,给出了一维光栅结构的等效折射率.描述了二维对称结构的一维近似分析方法及其等效折射率估算方法.为得到大的特征尺寸,提出了基脊和隙空的混合设计概念.     

亚波长结构抗反射表面的设计方法

对亚波长结构抗反射表面的设计原理和设计方法进行了较详细的论述，基于等效媒质近似理论，给出了一维光栅结构的等效折射率，描述了二维对称结构的一维近似分析方法及其等效折射率估算方法，为得到大的特征尺寸，提出了基脊和隙空的混合设计概念。     

图案几何参数对硅晶圆片表面吸收率的影响

利用时域有限差分法(FDTD)研究了晶圆片中SiO2沟槽尺寸变化对其表面吸收率的影响.同时利用等效介质理论(EMT)对预测结果进行了进一步解释分析.计算结果表明,次波长光栅时,EMT可以很好地预测光谱吸收率的变化;当SiO2沟槽宽度增加时腔共振效应提高了晶圆片表面的吸收率;当光栅周期与入射波长大小相当且填充比不是很小时,吸收率曲线在短波长区会出现较为强烈的震荡.     

镀有敏感膜的长周期光纤光栅NO气体传感特性

为提高长周期光纤光栅(LPFG)化学传感器检测折射率小于1.4介质时的灵敏度,实现对一氧化氮(NO)气体的高灵敏度检测,采用在常规长周期光纤光栅包层外镀上折射率大于包层折射率的SiO2-WO3薄膜的方法,运用四层阶跃折射率耦合模理论,分析长周期光纤光栅谐振波长的光谱特性.当膜厚为最佳值时,谐振波长变化率最大,灵敏度最高.在室温下,用镀有不同膜厚的传感器检测体积分数为2%的NO气体.结果表明,只有镀3层膜的传感器谐振波长红移4.77 nm,灵敏度达3%,元件响应时间10 s,恢复时间20 s,其他膜厚的传感器谐振波长没有变化.     

森林环境电磁脉冲传播仿真的时域抛物方程方法

采用森林环境的3层等效模型,首先将植被等效为均匀有耗介质,推导有耗介质中电波传播的时域抛物方程方法,其次仿真电磁脉冲传播的时域特性,并通过傅里叶变换,给出了与Tamir经验值在频域的比较算例,最后证明时域抛物方程方法的有效性.     

平面多层介质中时谐辐射场的Green函数

利用物理方法求解了平面分区介质中时谐辐射场的Green函数,以三层介质结构为例,给出系统的等效反射率和折射率。结果表明,当源点与场点在边层介质中时,其Green函数具有行波形式,复合介质层的作用可用系统等效参数描述;而内域介质层中的Green函数,则因介质界面对波的折射和多次反射,使之满足边界条件,因而还附有驻波形式的通解。     

BST负折射特性实验验证

对钛酸锶钡BaxSr（1-x）TiO3（0〈x〈1）（BST）柱阵列异向介质棱镜的负折射进行了实验验证．实验结果表明,该BST柱构成的三维异向介质的负折射特性不依赖于柱体的排列周期,而是BST柱自身的谐振造成了电磁波在该棱镜中的负折射．BST柱排列周期仅对二次负折射的强度产生影响．例如：周期阵列的BST柱异向介质棱镜的斜边是阶梯状时,因具有光栅结构,使得在该斜边上发生的二次负折射被增强;随机阵列的BST棱镜的斜边不具有光栅结构,观察到的二次负折射就比较弱．采用等效介质理论的仿真结果与我们的实验结果符合较好．     

用3.1 eV光辐射测量法研制光纤Bragg光栅

给出了用3.1 eV(波长400 nm)荧光监测法在载氢商用通信光纤上制作光纤Bragg光栅的实验.采用244 nm SHG(二次谐波振荡):氩离子激光器和振动掩模,在其Bragg中心波长(λ=1 550.65 nm),得到反射率96%和3 dB带宽0.2 nm的光纤光栅.这种光纤光栅在光纤传感系统具有广泛的应用价值.     

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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