Spatiotemporal quasiperiodicity transition to chaos in the one-way coupled bistability lattice system

One-way coupled optical bistability lattice (OCBL) system for open flow is investigated. By using numerical simulations spatiotemporal quasiperiodicity is found. A rough phase diagram indicating the main spatiotemporal dynamic behavior in weakly coupled lattice is given. The transitions between spatiotemporal quasiperiodicity and chaos are observed. This result is important for the understanding of turbulence. Project supported by the Natural Science Foundation of Hebei Province.     

有机电双稳态器件

有机电双稳态器件(organic electrical bistability devices,OEBDs)具有低成本、易加工、小体积、快响应、低功耗和高存储密度等优点,在未来的信息存储和逻辑电路方面有着非常广阔的应用前景,正受到人们越来越多地的关注。但是有机电双稳态器件的工作原理还没有得到很好地理解,并且工作过程中所涉及的新概念、新理论等基本科学问题以及制备和加工过程中所涉及的新结构、新方法、新技术和新材料还有待进行深入地研究。本文综述了有机电双稳态器件近年来的研究进展,并探讨了它在电开关存储方面的应用前景以及需要解决的问题。     

基于表面等离子体激元纳米微腔的光学双稳态

在狭缝金属波导内放入非线性介质,利用非线性Kerr效应以及金属-非线性介质-金属所构成表面等离子体激元Fabry-Perot微腔形成的正反馈机制,在纳米尺度光子器件内实现光学双稳态。时域有限差分计算结果表明,由于表面等离子激元的局域增强效应,双稳态可以在低入射光强条件下发生。     

含负折射率介质非线性Bragg腔的双稳态特性

研究了含负折射率介质一维光子晶体非线性Bragg腔的透射特性、光学增强和双稳态特性.对负折射率介质无色散和有色散非线性Bragg腔及由两种正折射率介质构成的非线性Bragg腔的透射谱、光学增强、缺陷模的线宽、入射光的红移量、双稳态开关阈值进行了比较.含负折射率介质的非线性Bragg腔可显著增大腔内光学增强效应,降低缺陷模的线宽、入射光的红移量和双稳态开关阈值.     

基于光纤Fabry-Perot滤波器的电光混合光学双稳态

提出了一种新型的电光混合光纤光学双稳装置,它由波长为1.55μm带尾纤的DFB半导体激光器、全光纤可调谐Fabry_Perot滤波器和电光反馈电路构成。实验中通过改变输入光强实现了光学双稳运转。讨论了该双稳器件在激光光强稳定器和光纤传感器方面的应用。     

掺铒光纤中的双稳态现象的研究

在以掺铒光纤为增益介质的环形光纤激光器中观察到了光学双稳态现象,定性分析了双稳态形成的机理,即掺铒光纤不同位置分别存在增益饱和和吸收饱和,而且吸收饱和有着更低的饱和阈值。通过理论衍生的公式对增益特性曲线进行了拟合,并结合增益特性曲线对光双稳态的产生给出了定量的解释。     

光学双稳性的强迫振动模型

本文提出一个新的光学双稳性模型.基于平均场近似,慢变振幅近似和绝热近似的思想,把光学双稳系统看成一个“黑箱”,类比非线性振动理论,指出不同的光学双稳过程(包括不同的工作物质和不同的腔(F-P腔或环腔)),能用一个恰当的强迫振动方程统一地描述.方程中所包含的都是可测量的宏观参量,使得可能直接用实验拟合,与理论结果进行定量对照.用振动理论的方法,把方程演变成自治方程组,从而方便地得到光学双稳性稳态和动态解的一般形式.并用若干已报道的具体例子验证了这个模型的普适性.     

Qualitative behavior of systems of tumor–CD4+–cytokine interactions with treatments

Immunotherapies are important methods for controlling and curing malignant tumors. Based on recent observations that many tumors have been immuno‐selected to evade recognition by the traditional cytotoxic T lymphocytes, we propose mathematical models of tumor–CD4⁺–cytokine interactions to investigate the role of CD4⁺ on tumor regression. Treatments of either CD4⁺ or cytokine are applied to study their effectiveness. It is found that doses of treatments are critical in determining the fate of the tumor, and tumor cells can be eliminated completely if doses of cytokine are large. Bistability is observed in models with either of the treatment strategies, which signifies that a careful planning of the treatment strategy is necessary for achieving a satisfactory outcome. Copyright © 2014 John Wiley & Sons, Ltd.     

Optical bistability via quantum interference from incoherent pumping and spontaneous emission

We theoretically investigate the optical bistability (OB) in a V-type three-level atomic system confined in a unidirectional ring cavity via incoherent pumping field. It is shown that the threshold of optical bistability can be controlled by the rate of an incoherent pumping field and by interference mechanism arising from the spontaneous emission and incoherent pumping field. We demonstrate that the optical bistability converts to optical multi-stability (OM) by the quantum interference mechanism.     

径向压缩单壁碳纳米管的力学行为

寻求具有卓越性能而又易于制造的纳米开关是纳米科技界的一个研究热点. 首先基于碳纳米管的结构双稳性提出了一种纳米开关的原型设计, 其由关到开的转换可通过径向压缩实现; 然后利用基于REBO-II作用势的分子动力学模拟, 系统分析了径向压缩单壁碳纳米管的力学行为和不同纳米管的双稳性特征, 给出了一些纳米管双稳性的特征参数, 对于工程设计具有一定的指导意义.