非线性光纤耦合器中三阶色散对孤子脉冲作用研究

对双芯光纤中三阶色散影响下光孤子的传输特性进行了数值模拟计算,讨论了三阶色散所引起的孤子的线性的时间延迟,它既不同于自陡峭效应引起的延迟,也不同于自频移效应引起的延迟,而是另一种独立的管迟,这种三阶色散延迟,这种三阶色散延迟对于光耦合工关特性将产生一定程度的影响。     

二阶光孤子传输波形失真的补偿

研究了高阶效应影响下,色散位移光纤中二阶孤子间的相互作用,分析了二阶孤子对衰变后时域波形的变化．研究表明,引入非线性增益控制和谱共轭相结合的方法可以有效抑制孤子间互作用,实现波形失真的补偿,并且孤子脉冲不偏离原来的时间槽。     

高阶非线性对双折射光纤中亮孤子成形的影响

本文采用拉格朗日近似方法讨论了高阶非线性对双折射光纤中亮孤子传输特性的影响，给出了计入五阶非线性时入射到双折射光纤中的光脉冲演化成束缚亮孤子对的阈值条件．研究结果表明，与不计入高阶非线性的情形相比，正的高阶非线性减小入射脉冲演化成束缚亮孤子对的振幅阈值；负的高阶非线性的存在，不仅提高了入射脉冲演化成束缚亮孤子对的振幅阈值，而且还存在着入射脉冲演化成束缚亮孤子对的振幅上界.     

饱和非线性光纤中孤子传输特性的数值研究

文章以包含五阶非线性效应的高阶非线性薛定谔方程为模型,数值分析了饱和非线性光纤中孤子的传输特性.结果表明,五阶非线性效应影响下,皮秒孤子间的相互作用与不含五阶非线性效应孤子情况并不相同,其相互作用更为严重.这对光孤子通信系统是非常有害的.数值计算结果发现,同时采用不等振幅和不等位相法,选取合适的振幅比和相对相位可以对孤子间的相互作用进行有效的抑制.     

超高速光孤子传输特性分析及数值模拟

通过数值解非线性耦合薛定谔方程,研究高速光孤子通信系统中高阶色散和偏振模色散对孤子传输的影响,并数值模拟孤子在单模光纤中的演变。研究结果表明：偏振模色散导致孤子脉冲展宽、峰值功率下降、峰值点随传输距离漂移;高阶色散和偏振模色散使孤子加速展宽、脉冲沿出现非对称的振荡结构,脉冲峰值点随传输距离的漂移而发生改变。     

五次非线性对光孤子传输的影响

光孤子传输中的高阶非线性效应一直是光纤通讯发展的制约因素,本文从理想基态光孤子传输方程入手,以数值方法、傅里叶变换为手段,以MATLAB为工具,模拟五次非线性对光孤子传输的影响.通过编程模拟得到结果,在入射功率较大的时候(我们取50 W),此时五次非线性效应不可忽略,有γ20时,它将抑制高阶孤子的形成,为自散焦现象;当γ20时,它将促进高阶孤子的形成,为自聚焦现象.同时γ2会导致脉冲产生侧峰.     

超短DM光孤子系统中自频移影响及其抑制方法

针对色散管理孤子系统中孤子幅度、脉宽等参数的动态周期变化特性,采用时域和导频滤波复合控制方法,建立了光脉冲的传输方程,研究了短皮秒DM光孤子系统中控制孤子自频移(SSFS)影响的可行性和有效性,采用变分法分析了高速DM啁啾高斯准孤子在喇曼自频移条件下传输演化特性,采用沿线上导频滤波控制方法,将自频移控制在设计范围内,稳定了孤子中心频率.对40 Gbit/s长距离高速DM孤子传输系统的传输特性进行了数值模拟,所得结果与理论分析完全一致.     

高阶色散和五阶非线性对类明孤子传输特性的影响

从修正的非线性薛定谔方程(MNLSE)出发,采用变分法,导出了在高阶色散和五阶非线性共同作用下类明孤子脉冲参数随传输距离的演化方程组;求出了振幅与脉宽、脉宽与啁啾之间的约束关系及脉宽随传输距离演化的解析解;分析讨论了光纤中高阶色散和五阶非线性共同作用对类明孤子传输特性的影响.     

高速孤子传输系统稳定性研究

定时抖动是通信系统的重要性能指标,本文从光孤子的基本概念入手,根据光脉冲的传输动力学方程,采用变分法分析高斯准孤子在孤子互作用和高阶效应条件下传输演化特性的影响以及产生定时抖动的机理.本文研究了光孤子通信系统的传输控制理论及其数学模型,采用时域和频域复合控制的方法,建立了光脉冲的传输方程,采用变分法研究了波分复用系统中孤子互作用,自陡峭和拉曼效应等扰动因素对孤子参数演化的动力学方程,得出了孤子传输系统定时抖动的计算公式,比较了几种信道间隔下的孤子互作用,采用时域和频域复合控制方法有效的抑制孤子的定时抖动,从而延长的孤子系统的传输距离.设计了160Gb/s长距离高速孤子传输系统并对传输特性进行了数值模拟,结果与理论分析一致.     

非线性Schrdinger 方程在光纤通讯中的应用(英文)

综述了非线性Ｓｃｈｒ¨ｏｄｉｎｇｅｒ 方程在光纤通讯系统中的一些应用，主要内容有：１） 光纤中Ｎ孤子相互作用；２） 光纤中的脉冲传播；３） 在色散移位光纤中的飞秒孤子孤子相互作用；４） 强耦合非线性参数孤波；５） 光纤中有限带宽孤子传播的高阶效应；６） 用非线性环形反射镜对有限带宽孤子传输中的噪声积累进行抑制。     

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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