单摆混沌现象的研究

利用MATLAB软件强大的数值计算功能,使用龙格库塔法严格求解无阻尼单摆和有阻尼单摆的运动方程,研究单摆摆长、阻尼系数和初始摆角对单摆运动的影响．研究结果表明：单摆的周期与初始摆角有关,单摆周期随初始摆角的增大而增大;当两种单摆的参数取值处于某些范围肘,均能出现混沌现象;阻尼单摆在正阻尼条件下演化出随机吸引子,在负阻尼条件下演化出随机排斥子．通过计算不同参数值的单摆方程,发现单摆的运动对初始摆角、阻尼系数有很强的依赖性．最后提出了一种衡量混沌系统敏感性的量化指标——敏感系数,计算结果表明,初始摆角、单摆摆长、阻尼系数均能影响单摆的敏感系数．     

大角度单摆运动的周期研究

对单摆运动进行了讨论。单摆的周期是物理学中的一个基本问题,通过力学分析,建立了单摆的动力学方程,用机械能守恒定律分析了单摆周期,并给出了精确公式。利用三角函数作为一种近似方法,对单摆的动力学方程进行了简化,给出了大角度条件下单摆运动的周期的近似公式。对近似公式和精确公式进行了对比,最后进行了数值计算,结果表明,所得到的单摆运动周期的近似公式在大多数情况下都与精确公式符合的很好。     

单摆混沌现象的研究

利用MATLAB软件强大的数值计算功能,使用龙格库塔法严格求解无阻尼单摆和有阻尼单摆的运动方程,研究单摆摆长、阻尼系数和初始摆角对单摆运动的影响.研究结果表明:单摆的周期与初始摆角有关,单摆周期随初始摆角的增大而增大;当两种单摆的参数取值处于某些范围时,均能出现混沌现象;阻尼单摆在正阻尼条件下演化出随机吸引子,在负阻尼条件下演化出随机排斥子.通过计算不同参数值的单摆方程,发现单摆的运动对初始摆角、阻尼系数有很强的依赖性.最后提出了一种衡量混沌系统敏感性的量化指标——敏感系数,计算结果表明,初始摆角、单摆摆长、阻尼系数均能影响单摆的敏感系数.     

复杂单摆的KAM理论

建立了一类复杂单摆的运动方程.首先利用一个动量守恒的首次积分将二自由度系统转化为单自由度系统,然后利用KAM理论,将重力能量作为小扰动项,研究了复杂单摆的运动规律.研究表明:当重力能量与总能量相比很小时,或者单摆总能量充分大时,复杂单摆的KAM不变曲线仍然存在,整个系统做拟周期运动,扰动系统仍然具有无重力系统的运动规律...     

大摆幅单摆的运动研究

详细讨论了单摆的运动情况,指出了两种不同的单摆(刚性摆和柔性摆)在大摆幅的情况下运动的区别。并与小摆幅的情况做了对比,从而对单摆的运动规律有了一个更加完整的认识。     

基于智能手机的单摆实验创新设计

利用智能手机视频录制功能与视频分析软件相结合,对单摆运动实验进行了创新设计,对单摆运动的y－t图像分别进行傅里叶分析和数值拟合,计算单摆运动的周期。该方法简单易行,精确度高。将其应用于实际教学,效果好,学生实验兴趣高。     

从单摆到混沌--计算机辅助教学一例

介绍了计算机辅助单摆运动的教学过程，给出了相空间单摆运动的相轨迹，并就相关问题进行了讨论。     

单摆法测量空气密度实验分析

考虑空气浮力对单摆运动的影响,从单摆运动方程出发,计算得出振动周期与空气密度的关系,通过测量两个不同密度摆球单摆的相关物理量,求出空气密度,并分析了空气浮力对测量重力加速度的影响.     

单摆Duffing振子系统建模及其非线性特性数值仿真分析

从单摆问题引出Duffing方程问题,推出了关于Duffing振子的单摆运动方程.利用Matlab进行数值仿真模拟,分析了其运动中的分岔、Lyapunov指数和混沌等非线性特征.     

关于单摆方程的C++语言数值解法

文章运用C 语言给出了非线性单摆运动方程的数值解法,并依据程序的计算结果描绘了非线性单摆的振动曲线及相图,还定量研究了非线性单摆的振动周期与振幅的关系.     

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