Performance of third-order ghost imaging with second-order intensity correlation

The third-order ghost imaging with the second-order intensity correlation is theoretically and experimentally demonstrated.The resolution and visibility of the reconstructed image are discussed,and the relationship between resolution and visibility is analyzed.The theoretical results show that a tradeoff exists between the visibility and resolution of the reconstructed image;the better the image resolution,the worse the image visibility.Numerical simulations are carried out to verify this theory,and a ghost...     

水轮机活动导叶内部三维固液两相紊流计算及磨损预估

本文报导了水轮机活动导叶内部固液两相紊流的三维数值分析结果和磨损预估结果。文中基于N－S方程和两相紊流的k—ε—Ap模型,采用贴体坐标和交错网格系统,用SIMPLEC算法对水轮机活动导叶内部的固液两相紊流进行数值模拟,提出设计工况时活动导叶内部的两相紊流特性。在数值模拟的基础上,根据Finnie模型预估了活动导叶的磨损。并与Drtina的实验结果进行了比较．     

Narrow-linewidth single-polarization frequency-modulated Er-doped fiber ring laser

We demonstrate a 1550-nm narrow-linewidth fiber ring laser with stable single polarization by using single-mode Er-doped fiber as active fiber and saturable absorber. A polarization-maintaining circulator is used to acquire single-polarization laser light with the degree of polarization of 99.8%--99.9%. The linewidth measured using a delayed self-heterodyne method is less than 0.5 kHz. Frequency of the fiber laser can be modulated by driving the waveguide phase modulator with proper voltage. A Mach-Zehnder interferometer with the optical path difference between two arms of about 36 km is used to study the long-distance coherent detection of the fiber laser for frequency-modulated continuous-wave application.     

利用量子纠缠态确定性地降低通信复杂度

文章提出一种确定性地降低两体系系统中的通信复杂度的方案，它利用了一组处于任意纠缠纯态的粒子对。在这个方案中，对于一个任意的两变量布尔函数，一个被通信双方事先分享纠缠态可以使通信复杂度降低。与只通过经典通信或双方仅仅通过交换经典信息相比较而言，利用本方案其通信复杂度降低了一个比特。     

TiO2纳米管的电化学性能研究

以锐钛矿相TiO2粉末和氢氧化钠作原料,应用化学合成法,于高温高压反应釜中制备TiO2纳米管.TEM、XRD分析显示,所得产物为锐钛矿相四方结构的TiO2纳米管.恒流充放电、循环伏安法测试表明,该TiO2纳米管首次嵌锂容量达260 mA.h/g,可逆容量高,有希望成为未来一种较好的新型锂离子电池负极材料.