A new three-dimensional chaotic system and its modified generalized projective synchronization

Based on the Chen chaotic system,this paper constructs a new three-dimensional chaotic system with higher order nonlinear term and studies the basic dynamic behaviours of the system. The modified generalized projective synchronization has been observed in the coupled new three-dimensional chaotic system with unknown parameters. Furthermore,based on Lyapunov stability theory,it obtains the control laws and adaptive laws of parameters to make modified generalized projective synchronization of the coupled new three-dimensional chaotic systems. Numerical simulation results are presented to illustrate the effectiveness of this method.     

智能卡和口令结合的动态认证方案

远程认证协议能有效的保证远程用户和服务器在公共网络上的通信安全。提出一种匿名的安全身份认证方案,通过登录 的动态变化,提供用户登录的匿名性,通过用户和服务器相互验证建立共享的会话密钥,抵抗重放攻击和中间人攻击,实现用户安全和隐私,通过BAN逻辑分析证明改进方案的有效性,通过安全性证明和性能分析说明了新协议比同类型的方案具有更高的安全性、高效性。     

Kondo Resonance versus Fano Interference in Double Quantum Dots Coupled to a Two-Lead One-Ring System

We analyse the transport properties of a coupled double quantum dot （DQD） device with one of the dots （QD1） coupled to metallic leads and the other （QD2） embedded in an Aharonov-Bhom （A-B） ring by means of the slaveboson mean-field theory. It is found that in this system, the Kondo resonance and the Fano interference exist simultaneously, the enhancing Kondo effect and the increasing hopping of the QD2-Ring destroy the localized electron state in the QD2 for the QD1-leads, and accordingly, the Fano interference between the DQD-leads and the QD1-leads are suppressed. Under some conditions, the Fano interference can be quenched fully and the single Kondo resonance of the QD1-leads comes into being. Moreover, when the magnetic flux of the A-B ring is zero, the influence of the parity of the A-B ring on the transport properties is very weak, but this influence becomes more obvious with non-zero magnetic flux. Thus this model may be a candidate for future device applications.     

Phase Transition and EOS of Marmatite （Zn0.76Fe0.23S） up to 623K and 17 GPa

In situ energy dispersive x-ray diffraction for natural marmatite （Zn0.76Fe0.23S） is performed up to 17. 7 GPa and 623 K. It is fit, ted by the Birch-Murnaghan equation of state （EOS） that Ko and α0 for marmatite are 85（3）GPa and 0.79（16）＊10^-4 K^-1, respectively. Fe^2＋ isomorphic replacing to Zn^2＋ in natural crystal is responsible for high bulk modulus and thermal expansivity of marmatite. Temperature derivative of bulk modulus （OK/OT）p for marmatite is fitted to be -0.044（23） GPaK^-1. The unambiguous B3-B1 phase boundaries for marmatite are determined to be Pupper（GPa）= 15.50 - 0.016T（℃） and Plower （GPa）=9.94-0.012T（℃） at 300-623K.     

目标图像长宽比对Vander Lugt相关器特性的影响

分析了使用VLC进行光学相关识别时目标图像长宽比的变化对匹配滤波器畸变容限和输出相关峰值的影响。利用非约束纯相位匹配滤波器算法和迂回相位编码方法设计匹配滤波器,对具有确定面积和透过率而长宽比不同的矩形目标进行光学相关识别。模拟和实验结果表明：随着目标图像长宽比增加,匹配滤波器畸变容限减小,相关峰值降低。VLC更容易识别长宽比趋近1的目标图像。     

BaWO_4晶体的拉曼光谱分析

BaWO4晶体是一种很有应用前景的喇曼激光晶体。本文根据对称性分类,用商群理论分析了Ba-WO4晶体的喇曼光谱。一个原胞中含有两个BaWO4分子,理论上有36个振动膜,和我们用群论计算得数目一致。其中有18支拉曼活性光学膜。我们测得了10支拉曼峰,并对测得的各个配置的拉曼峰进行了指认,其中X(ZZ)X配置921cm-1处的喇曼峰强度最强,线宽较窄,对于作为喇曼激光晶体来讲是很有益的。     

Universal Scaling Law for Atomic Diffusion and Viscosity in Liquid Metals

The recently proposed scaling law relating the diffusion coefficient and the excess entropy of liquid [Samanta A et al. 2004 Phys. Reu. Lett. 92 145901; Dzugutov M 1996 Nature 381 137], and a quasi-universal relationship between the transport coefficients and excess entropy of dense fluids [Rosenfeld Y 1977 Phys. Rev. A 15 2545],are tested for diverse liquid metals using molecular dynamics simulations. Interatomic potentials derived from the glue potential and second-moment approximation of tight-binding scheme are used to study liquid metals.Our simulation results give sound support to the above-mentioned universal scaling laws. Following Dzugutov,we have also reached a new universal scaling relationship between the viscosity coefficient and excess entropy.The simulation results suggest that the reduced transport coefficients can be expressed approximately in terms of the corresponding packing density.     

Design of Two-Dimensional Photonic Crystal Edge Emitting Laser for Photonic Integrated Circuits

An edge emitting laser based on two-dimensional photonic crystal slabs is proposed. The device consists of a square lattice microcavity, which is composed of two structures with the same period but different radius of air-holes, and a waveguide. In the cavity, laser resonance in the inner structure benefits from not only the anomalous dispersion characteristic of the first band-edge at the M point in the first Brillouin-zone but also zero photon states in the outer structure. A line defect waveguide is introduced in the outer structure for extracting photons from the inner cavity. Three-dimensional finite-difference time-domain simulations apparently show the in-plane laser output from the waveguide. The microcavity has an effective mode volume of about 3.2（λ/nslab）^3 for oscillation mode and the quality factor of the device including line defect waveguide is estimated to be as high as 1300.     

稀土共晶闪烁材料研究进展

闪烁材料已经被广泛用于高能物理、核医学影像、工业无损检测、港口安全检查、地质勘探、航天探测等领域。具有5d→4f允许跃迁的三价稀土离子激活的稀土闪烁材料具有高光输出和快荧光衰减特性,已成为无机闪烁材料的重要组成部分。随着上述各应用领域,尤其是核医学诊断对成像分辨率提出了越来越高要求,核医学影像对探测成像设备的核心材料——闪烁材料性能的要求也有了更高的要求。最近研究表明,具有有序微纳结构的共晶闪烁材料由于具有微米级的像素单元,在对高能射线探测中可显著提高成像分辨率,而受到了特别的关注。本文从共晶闪烁材料的制备、性能优化及应用等方面,综述了稀土共晶闪烁材料中有序微纳结构的形成机制及其对材料闪烁性能的影响,以及近年来稀土共晶闪烁材料的研究进展。     

NⅢ—ArⅩⅣ离子的双电子激发六重态跃迁的理论计算

根据相对论多组态理论，采用ＧＲＡＳＰ２（１９９２）程序计算了ＮⅢ—ＡｒⅩⅣ的１ｓ２ｓ２ｐ３６Ｓ０－１ｓ２ｓ２ｐ２３ｄ６Ｐ跃迁精细结构，计算的波长值与Ｊ．Ｈ．Ｂｌａｎｋｅ［１］等人的计算值和实验值进行了比较，并为六重态离子谱线辨识提供了有益的参考。