用改进的线性近似方法研究单模激光损失模型随机共振

采用周期信号、具有实虚部关联的量子噪声和抽运噪声作用下的单模激光损失模型,运用改进的线性化近似方法计算得到了模型输出光强的相关函数、功率谱及信噪比.分析了激光的净增益系数、噪声强度和输入信号对信噪比(SNR)随量子噪声实虚部关联系数(λ)变化曲线的影响.研究发现了信噪比随量子噪声实虚部系数的变化出现了新的随机共振现象.     

关联噪声驱动下单模激光损失模型的输出功率

运用线性化近似方法分析具有实虚部关联的量子噪声和泵噪声驱动的单模激光损失模型的动力学性质,计算了光强的关联函数、功率谱及输出功率,讨论了量子噪声实虚部关联系数λq,量子噪声强度P和净增益系数a0对输出功率的不同影响,并发现输出功率S随λq,的关系曲线在a0改变时出现了类似于概率分布中的“重复相变”等新现象．     

亚硝酸钠光学性质的第一性原理研究

为了更好地理解亚硝酸钠在铁电相和顺电相间光学性质的差异，计算了它的介电虚部ε2(ω)、光吸收系数I(ω)及反射系数R(ω)．ε2(ω)、I(ω)和R(ω)的计算结果表明，亚硝酸钠是一种各向异性比较明显的材料，并且其光学性质在铁电相中要比在顺电相中具有更高的各向异性．     

基于FFT的正弦信号频率估算新方法

介绍一种新的基于FFT的正弦信号频率估计的插值方法。该方法利用了DFT最大值谱线及与其相邻两根谱线系数的实部(或虚部)进行插值得到频率估计值。与传统的算法不同,在本方法中不需要判断第二大峰值谱线的位置,避免了找该谱线时可能会出错,从而使频率估算值出错的问题。另外,插值时算法中先对几根谱线DFT系数的实部和虚部的大小进行比较,实部大于虚部时用利用实部进行插值,反过来则利用虚部进行插值,从而减少了噪声的影响并提高了估算精度。数值模拟结果表明利用该方法可以得到良好的插值效果,能取得很小的频率估算偏差。     

用有效介质理论模拟Ag/AAO纳米有序阵列复合结构光学常数

运用Maxwell—Garnett有效介质理论，计算了Ag／阳极氧化铝（AAO）纳米有序阵列复合结构的光学常数（250～2000nm波段），探讨了Ag组分的体积分数对Ag／AAO光学常数的调制作用和Ag纳米粒子的长径比对其表面等离子共振吸收的影响．模拟结果表明，随着Ag组分体积分数的增加，在小于450nm波段，Ag／AAO复合结构的介电函数实部和折射率均逐渐减小，而介电函数虚部和消光系数逐渐增大；在大于450nm波段，Ag／AAO复合结构的介电函数实部、介电函数虚部及折射率均逐渐增大，消光系数则变化较小．模拟结果显示出Ag纳米粒子的长径比与复合结构表面等离子共振吸收峰位有较强的相关性．另外，理论模拟预期透射谱也与实验透射谱变化趋势一致．     

等离子体噻吩聚合膜紫外吸收的讨论

从等离子体噻吩聚合膜的反射谱和透射谱,运用传递距阵方法计算得到膜的光学常数:折射率n_f和消光系数k_f(受测量仪器限制,反射谱和透射谱以能量(?)ω表示的频率宽度为0.4～4.0 eV)。等离子体噻吩聚合膜在这个频率宽度内,没有显示出对光的强吸收。由膜的折射率谱及塞尔迈耶公式,可推断在大于4.0 eV紫外区,等离子体噻吩聚合膜存在一定强度的吸收。并进一步利用复数介电函数的实部与虚部之间的 k-k关系,以振子模型进行外推,对等离子体噻吩聚合膜的紫外吸收进行讨论。     

电子计算机在防振油锯设计中的应用

<正>本文从油据系统的频响函数H(ω)出发,较全面地论述了油锯系统的力学模型的确定和简化,用傅氏变换的方法求解油锯系统的常系数微分方程,应用电子计算机,对油锯系统的质量、刚度及其分布进行优化设计,使得对人体最敏感的振动带内的|H(ω)|1。     

量子噪声实虚部关联对饱和激光模型光强涨落的影响

文章基于实、虚部关联的量子噪声及泵噪声驱动的饱和激光模型，推导了近似福克—普郎克方程、激光强度定态概率分布函数，通过计算机进行数据计算及作图，得到了定态情况下光强概率分布函数图形，讨论了量子噪声实、虚部的互关联对光强关联函数的影响。结果表明：量子噪声实、虚部互关联会增大激光强度的涨落。     

修正条纹调节的圆谐联合变换相关器作旋转不变的目标检测

提出一种修正条纹调节的圆谐联合变换相关器作旋转不变的目标检测的方法．在这种方法中,参考图像（即圆谐展开分量的实部和虚部）、圆盘状的局部偏置函数以及目标图像同时显示于输入面．这一方法对联合功率谱作了修正,先将联合功率谱减去纯输入景物（含局部偏置函数）的功率谱和参考图象（含局部偏置函数）的功率谱,再加上局部偏置函数的功率谱,然后将所得修正的联合功率谱乘以条纹调节滤波函数．它能产生比普通的圆谐联合变换相关器更好的相关输出．给出计算机模拟结果．     

实虚部间关联泵噪声对激光动力学性质的影响

在损失模型中引入平方色泵噪声,并考虑泵噪声实虚部间关联λp,推导了一个新的含有λp的光强朗之万方程.用线性化近似的方法从理论上对具有实虚部间关联的泵噪声驱动的单模激光的动力学性质进行分析,计算了光强的关联函数、功率谱及输出功率S.讨论了泵噪声实虚部间的关联强度λp、泵噪声强度p'、净增益系数a和关联时间τ对S的影响,发现λp对光强的输出功率影响显著.当λp=±0.5时,输出功率S最大,|λp|=1或λp=0时,输出功率S最小.     

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