忆阻蔡氏对偶混沌电路分析

提出了用分段单调荷控忆阻器代替对偶蔡氏混沌电路中的非线性电阻,构造出基于忆阻器的对偶蔡氏混沌电路。对该忆阻蔡氏对偶混沌电路的理论推导、稳定性、Lyapunov 指数和数值仿真等动力学特性进行了分析。研究结果表明：该系统为双涡卷混沌吸引子,该忆阻蔡氏对偶混沌电路的动力学特征对初值敏感异于普通混沌电路。     

一种含有磁控忆阻器的四阶混沌电路的特征分析

该文提出了一种简单的磁控忆阻器模型,并利用它设计了一个混沌电路。通过数值模拟计算得到了一个三维带状混沌吸引子,且此时忆阻器的伏安特性曲线不是传统的"8"字形。通过计算系统的相图、分岔图和Lyapunov指数谱,发现调节电容参数或忆阻器初始状态可以实现电路系统在混沌态和各周期态之间的转变,发现调节磁通能使系统出现二周期到四周期再回到二周期的奇特分岔现象。该研究工作对利用忆阻器设计混沌电路并应用于密码通信具有积极的参考价值。     

基于Chua电路的一个超混沌系统的控制同步

Chua电路具有广泛的应用价值,受到越来越多的研究者的关注.借助于最新提出的忆阻器电路元件,在Chua系统的基础上构造了一个新的超混沌系统.通过PC控制和线性反馈方法,分析了两个线性耦合的超混沌系统的同步,数值仿真也验证了理论分析的有效性.     

基于最优控制的一类忆阻混沌系统的同步

本文基于线性二次型问题的最优控制理论,研究了蔡氏忆阻混沌系统的同步问题,提出了一种实现蔡氏忆阻混沌系统同步的方案。并利用李雅普诺夫稳定性定理证明了两个同构蔡氏忆阻混沌系统达到同步的充分条件。该方法能够实现控制能量消耗和同步误差的综合最优。数值仿真结果验证了文中所给方法的有效性。     

一种基于有源忆阻器模型的混沌电路

提出一种内部状态变量导数中含有平方项的有源忆阻器模型;并基于该模型构造了一个仅含电容、电感和忆阻器三个元件的混沌电路系统。该系统仅包含有一个平衡点;且吸引子关于原点中心对称。通过系统的李雅普诺夫指数谱和分岔图发现,在不同的电阻参数下该系统会以混沌危机和倒分岔两种方式退出混沌。最后,利用运算放大器等对该忆阻器进行电路模拟,给出了混沌系统的电路实现。     

有源荷控忆阻器在非线性电路中的应用

根据理论分析,搭建了一种新的二端口有源忆阻器.该有源荷控忆阻器不使用光敏电阻和数字电位器,理论上比较精确,并且容易在实验中实现.仿真和实验证明了这种有源忆阻器和真正的无源忆阻器具有相同的电路特性.此外还将该有源忆阻器加入到蔡氏混沌电路中,在非线性电路中成功实现混沌现象,证明了它可以等效于一个二端口元件接入其它电路工作,为忆阻器的应用打下了基础.     

基于忆阻器的混沌电路设计与硬件实验

通过在经典QI混沌系统中加入三次非线性磁控忆阻器,构造出了一种四维忆阻混沌系统.分析了该系统的基本动力学特性,证明该系统可以产生混沌吸引子.设计了硬件电路,通过改变元件参数观察到不同类型的吸引子和极限环,实验结果与仿真结果相符合.提出的基于忆阻器的混沌电路设计与硬件实验方案不仅可以拓展传统混沌电路的实现方法,还为非线性...     

通过切换控制和模糊建模镇定基于忆阻的混沌系统

研究了以忆阻器为基础的混沌系统的稳定性.基于该系统建立了一个T-S模型并设计了一个开关控制器.通过李雅普诺夫稳定性理论,取得了一个以保证结论成立的准则.最后用数值结果验证了本研究方法的有效性.     

基于忆阻器的固定时间混沌通信方法

混沌信号具有隐蔽性、不可预测性和高度复杂等特点，特别适用于保密通信和扩频通信等领域。为有效解决有限时间同步控制过度依赖初始条件的问题，基于固定时间稳定性理论，通过设计状态反馈控制器给出了忆阻神经网络实现固定时间同步的充分条件，并对停息时间进行了精确估计。在此基础上，以驱动混沌忆阻神经网络为发射器，以具有不同初值的响应系统为接收器，采用混沌遮掩的方式实施信号加载，实现在固定时间内恢复加密信号，确保保密通信的安全性和时效性。     

含忆阻器的并联混沌电路动力学分析

忆阻器在保密通信、图像加密中具有重要应用价值。本文提出一种有源压控忆阻器,将该忆阻器和电容、电感并联构成了一个基于忆阻器的并联混沌电路,建立了该系统的无量纲数学模型。采用基本动力学分析方法对系统进行分析,计算了该电路的Lyapunov指数和Lyapunov维数,通过数值仿真得出该系统的相轨图和Poincaré映射,分析了系统的平衡点稳定性,采用Lyapunov指数谱和分岔图等分析方法,研究了电路参数改变对系统动力学行为产生的影响。数值仿真和理论分析结果表明,该系统可以产生一类特殊的超混沌吸引子,并且随着电路参数的变化产生复杂的非线性动力学行为。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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