Experimental verification of enhanced transmission through two-dimensionally corrugated metallic films without holes

We present experimental results to verify extraordinary optical transmission through two-dimensionally periodic, corrugated metallic films without holes as predicted by Bonod et al. [Opt. Express 11, 482 (2003)]. We also experimentally confirmed that using symmetric structures (metallic films sandwiched between two identical dielectric media) is advantageous for boosting the coupling of surface plasmons so as to create strong transmission peaks.     

地层静温预测的非牛顿流体数学模型

根据热力学参数、泥浆参数及井筒结构参数等，先选定一个地层温度梯度进行计算，得出泥浆出口温度.将此计算值与实测温度值比较，按照比较结果再修正所选的地层温度梯度.如此反复，直到得出合理的地层温度梯度.在此基础上，从热力学及流体力学等有关方程出发， 经过推演得到井壁上温度随深度变化以及地层温度分布的数学模型.由于钻井过程中泥浆、 岩石及其温度场间是相互作用、相互影响的，这为研究热 流 固耦合渗流过程的理论与应 用提供了一种新的方法. 关键词： 温度梯度 非牛顿流体 数学模型     

冲击作用下的摩擦力效应实验研究

针对摩擦力效应产生的机理, 本文设计了三种不同尺寸的试件进行SHPB实验, 得到了摩擦力效应对实验的定量影响, 在此基础上对混凝土的DIF进行了修正研究, 为混凝土抗冲击工程设计提供了参考依据. 关键词： 冲击 混凝土 SHPB 摩擦力     

Nonclassical state via superposition of two coherent states (π/2 out of phase) and related entangled states

Nonclassical features of the superposition of two coherent states which are π/2 out of phase are discussed, such as sub-Poissonian photon statistics and quadrature squeezing, as well as negativity of the Wigner function. Special nonclassicality is found in the special state where the relative phase of superposition has relationship with the average photon number. The analysis of the amount of entanglement is also presented for the related two-mode entangled coherent states.     

The effect of electronic orbital interactions on p-type doping tendency in ZnO series： First-principles calculations

The electronic structures and optical properties of B3 ZnO series of Znelectronic structures, optical properties, pseudopotential plane-wave method, \\ \hspace*{1.9cm} p-type doping tendency,electronic structures, optical properties, pseudopotential plane-wave method, \\ \hspace*{1.9cm} p-type doping tendencyProject supported by the National Natural Science Foundation of China (Grant No~10625416).2007-04-252007-06-18The electronic structures and optical properties of B3 ZnO series of Zn4X4-yMy（X ：O, S, Se or Te; M = N, Sb, C1 or I; y = 0 or 1） are studied by first-principles calculations using a pseudopotential plane-wave method. The results show that Zn d-X p orbital interactions play an important role in the p-type doping tendency in zinc-based Ⅱ-Ⅵ semiconductors. In ZnX, with increasing atomic number of X, Zn d-X p orbital interactions decrease and Zn s-X p orbital interactions increase. Additionally, substituting group-V elements for X will reduce the Zn d-X p orbital interactions while substituting group-VII elements for X will increase the Zn d-X p orbital interactions. The results also show that group-V-doped ZnX and group-Ⅷ-doped ZnX exhibit different optical behaviours due to their different orbital interaction effects.     

One-step green route to narrowly dispersed copper nanocrystals

We report a total “green” chemical method in aqueous solution for synthesizing stable narrowly distributed copper nanoparticles with average diameter less than 5 nm in the presence of Polyvinylpyrrolidone (PVP) as a stabilizer and without any inert gas protection. In our synthesis route, ascorbic acid, natural vitamin C (VC), an excellent oxygen scavenger, acts as both reducing agent and antioxidant, to reduce the metallic ion precursor, and to effectively prevent the common oxidation process of the newborn pure copper nanoclusters.     

基于数字相干叠加的相干光正交频分复用系统中光纤非线性容忍性研究

光正交频分复用系统中的光纤非线性效应制约着系统进一步的扩容. 针对此问题, 提出一种数字相干叠加的方法, 用于提高相干光正交频分复用系统对光纤非线性的容忍性. 仿真中, 5通道的波分复用下偏振复用相干光正交频分复用系统的每个通道传输四进制正交振幅调制映射的71.53 Gbit/s信号在光纤中传输400 km. 首先, 通道间隔为25 GHz, 与传统相干光正交频分复用系统相比, 色散补偿前后, 使用数字相干叠加的相干光正交频分复用系统的信噪比分别提升了6.02 dB和9.05 dB, 最佳入纤光功率均增大了2 dB; 其次, 通道间隔为50 GHz, 色散补偿前后, 信噪比分别提升了4.9 dB和8.75 dB. 通过理论推导及仿真, 验证了所提方法能有效消除相干光正交频分复用系统的一阶非线性失真, 进而提高系统对光纤非线性的容忍性.