一类节点结构相同的复杂网络脉冲同步

研究采用脉冲方法实现复杂网络的混沌同步问题,考察了脉冲信号作用下复杂网络的稳定性,推导出稳定性判定定理,以判断能否用脉冲信号实现复杂网络的脉冲同步.研究得到:脉冲信号作用下复杂网络稳定性判定定理,并通过4个节点的蔡电路网络的同步问题说明定理的有效性和方便实用性,数值模拟验证了理论结果的正确性.该研究成果对复杂网络的同步提供了一个可行的选择方案.     

超混沌系统脉冲同步及其应用

研究了采用脉冲同步理论解决混沌系统的同步问题,并利用脉冲同步方法构造超混沌脉冲同步系统.根据同步渐进稳定性条件作为前提对系统进行数值仿真.采用同步误差的线性反馈作为脉冲信号,结合谱半径的稳定性定理采用合适的脉冲周期对系统进行了同步仿真实验.实现了超混沌系统的同步.并以正弦信号为例进行了信号传输的实验,进一步在加入白噪声的情况下考察了其同步效果.仿真效果表明,该方法具有较好的鲁棒性和抗噪能力,是对传统同步方法的改进和优化,具有一定的实际应用价值.     

不确定参数Liu系统的自适应同步在保密通信中的应用

基于稳定性理论,用自适应控制的方法构造了一个同步系统,实现对任意传输信号的及时准确恢复;用此方法对Liu系统进行了数值仿真,结果表明系统能很好地达到同步。将该系统应用到保密通讯中,信息信号和混沌信号相加构成混沌传输信号,在接收端信息信号能被有效复原,仿真研究表明该通信方案确实可行。     

CHEN系统同步及其在保密通讯中的应用

基于稳定性理论,用自适应控制的方法构造了一个同步系统,实现对任意传输信号的及时准确恢复;用此方法对CHEN系统进行了数值仿真,结果表明系统能很好地达到同步。将该系统应用到保密通讯中,信息信号和混沌信号相加构成混沌传输信号,在接收端信息信号能被有效复原,仿真研究表明该通信方案确实可行。     

基于区间同步实现混沌保密通信

利用区间同步方案实现混沌保密通信是基于脉冲和语音信号有一些间隙或一些幅度相对弱的区间的特点。在发射端,对语音信号在时域内进行压缩使其出现幅度为０－的一些区间,然后将脉冲信号或压缩后的语音信号对混沌信号进行调制。在接收端,利用约束来同步和自由演化同步,将所传送的脉冲信号或语音信号从已调制的混沌信号中提取出来。最后,以Ｈｅｎｏｎ映射和Ｄｕｆｉｎｇ混沌系统为例子进行计算机模拟。     

Rossller 混沌系统的脉冲同步在通信中的应用

利用脉冲控制方法构造了一个Rossller脉冲同步系统。并将它用于语音和图像的保密传输。从仿真效果看，该方法有较好的鲁棒性和抗噪能力。特别是它在掩盖通用中允许信号的幅度较大，这是传统的驱动－响应法－被动法和耦合同步法难以比拟的。     

Rossler混沌系统的脉冲同步在通信中的应用

利用脉冲控制方法构造了一个Rossller脉冲同步系统,并将它用于语音和图像的保密传输.从仿真效果看,该方法有较好的鲁棒性和抗噪能力.特别是它在掩盖通信中允许信号的幅度较大,这是传统的驱动-响应法、主动-被动法和耦合同步法难以比拟的.     

基于有序子集期望最大化的螺旋半扫描重建

提出了基于直接螺旋半扫描数据的有序子集期望最大化（OSEM）迭代重建．该方案省略了螺旋CT中对投影数据的插值步骤,利用螺旋CT中相邻重建层间的相似性,将当前层的重建结果作为下一层重建时OSEM算法的初始输入．实验结果表明,在螺距较小的情况下,该重建方案使得螺旋CT在重建质量优于滤波反投影的前提下,所需的重建时间显著减少．     

认识数字音频中的字时钟

数字音频设备必须在传输数字音频信号时同步,否则,数字音频信号可能不被正确地接收.可以通过一种叫做“字时钟”的方式来实现数字音频设备之间的同步：它实际上是在一个系统中为所有数字音频信号同步的时钟信号.本文揭示了该信号在同步过程中的工作原理和工作方式.     

认识数字音频中的字时钟

数字音频设备必须在传输数字音频信号时同步,否则,数字音频信号可能不被正确地接收.可以通过一种叫做“字时钟”的方式来实现数字音频设备之间的同步：它实际上是在一个系统中为所有数字音频信号同步的时钟信号.本文揭示了该信号在同步过程中的工作原理和工作方式.     

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.     

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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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