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。     

不确定信息处理及在归纳学习中的应用

信息的不确定性是由于模糊性、随机性、不完全性、不精确性等因素造成的,不确定性信息在现实世界中广泛存在.关于这方面的研究主要集中在模糊性这种不确定性上.我们课题组在此领域的研究已经持续20余年,概括起来讲,早期的研究兴趣在于模糊(非可加)测度与积分的理论建立,主要研究了传统的可加测度与积分理论到非可加情况的推广;尔后的兴趣转向为如何用数值方法确定非可加测度;近期的研究兴趣在于从已有数据中获取模糊控制规则以及具有模糊表示的归纳学习问题.近10年的研究曾得到了多项基金项目资助,出版专著3部,发表学术论文100余篇,30余篇被SCI收录,20余篇被EI收录,省级以上奖励3项.以下是我们近期研究工作的一个总结,主要包括模糊决策树归纳;基于模糊信息的决策表简化;产生模糊规则的扩张矩阵算法;模糊归纳学习在其他领域中的应用;基于示例学习的模糊控制等.     

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。     

时滞对磁通耦合及化学耦合神经元分岔及同步的影响

以化学突触耦合神经元模型为基础,讨论了抑制性及兴奋性条件下达到同步的区别及同步的类型.并根据磁通耦合对神经元放电的影响,讨论了具有时滞、磁通耦合和化学耦合Morris-Lecar(ML)神经元模型的放电状态、分岔类型及其同步情况.发现具有磁通耦合和化学耦合ML神经元系统在不同参数下会产生丰富的逆倍周期分岔或加周期分岔行为.而时滞的引入,虽然可以增加系统的周期性,但同时也会破环系统同步.相反,适当的耦合强度能够增加同步.