Numerical Simulation for Coherent and Partially Coherent Beam Propagation through Atmospheric Turbulence

Propagation properties of coherent and partially coherent beams in atmospheric turbulence are investigated respectively by using numerical simulation It is found that a partially coherent beam has a spreading larger than a coherent beam. However, from the point view of relative beam spreading and intensity scintillation, a partially coherent beam is less affected than the corresponding coherent beam, which may be the most important virtue of partially coherent beams that could be utilized to improve the performance of laser engineering. The beam wandering is almost independent of the degree of the source coherence. More aperture averaging occurs when beam becomes more coherent.     

光纤傅里叶变换光谱仪干涉图的对称化处理

偏离中心条纹的抽样以及光纤干涉仪的缺陷引起光纤傅里叶变换光谱仪(FFTS)输出的干涉图不对称,导致由傅里叶余弦变换计算得到的光谱带有相位误差,影响光谱的线型。文章首次将卷积方法应用到光纤傅里叶变换光谱仪中干涉图的对称化处理,利用干涉图的中心部分计算出相位误差,通过傅里叶变换得到了对称化处理函数,用卷积运算在时域完成了光谱的相位误差校正。实验研究表明,在FFTS中该方法能在时域有效地实现干涉图对称化,校正了光谱的相位误差。该方法不仅克服了双边干涉图的缺点,而且校正的结果有较高的准确度。     

混沌光通信与OC-48光纤通信的波分复用

数值证实并分析了混沌激光通信与现行光通信的波分复用传输,对于100 GHz的信道间隔,混沌激光通信系统实现了传输速率为1 Gbit/s数字信号的保密传输,现行光通信系统实现了传输速率为2.5 Gbit/s数字信号的传输.研究表明,当现行光通信中脉冲光信号的峰值功率不超过17 dBm时,混沌激光通信可在传输距离80 km内实现并行传输.此外,当现行光通信中脉冲光信号的峰值功率为7 dBm时,系统接收到的信号质量受混沌激光通信的干扰很小,当光纤传输距离从80 km增加到160 km时,对应的眼图开启度从82% 关键词： 混沌光通信 混沌同步 波分复用 信道串扰     

High efficiency broad bandwidth erbium-doped superfluorescent fiber source

A practical two-stage double-pass structure using high concentration erbium-doped fiber and 1480-nm pump laser diode is suggested for a high power and broad bandwidth erbium-doped superfluorcscent fiber source. A considerable increase in output power and bandwidth extension is achieved by adding an unpumped fiber and a broadband fiber mirror to make the most of wasted backward amplified spontaneous emission as both pump and input light source simultaneously. Superfluorcscent fiber source with nearly 80-nm bandwidth and 28.6-mW output power is obtained experimentally.     

基于TiO2的绿色多相催化剂催化CO2与环氧化合物偶联反应

金属离子掺杂纳米TiO2(M-TiO2,M=Zn2+,Cu2+,Co2+,Mn2+,Ni2+)在CO2与环氧化合物的偶联反应中表现出较高的催化活性.反应以四正丁基碘化铵(TBAI)为共催化剂,在无溶剂条件下进行.考察了反应温度、反应时间和CO2压力在Zn-TiO2/TBAI体系中对反应性能的影响.作为无毒的多相催化剂,Zn-TiO2可循环使用5次,其催化活性没有明显降低.     

Computations of Bergman Kernels on Hua Domains

The Bergman kernel function plays an important ro1e in several complex variables.There exists the Bergman kernel function on any bounded domain in Cn. But we can get the Bergman kernel functions in explicit formulas for a few types of domains only,for example:the bounded homogeneous domains and the egg domain in some cases.     

巧用圆规画线段

在七年级上学期数学的学习中,我们知道了可以用直尺和圆规(简称尺规法)画一条线段等于已知线段,我们又知道只用直尺画线段是一件很容易的事情,那么,能否用圆规来画     

Reinhardt域的最大全纯自同构群的Bergman核函数

By using the transformation rule for the Bergman kernel functions under proper holomorphic mappings and the theorem of Lu Qikeng,the Bergman kernel function and full group of holomorphic automorphism for a Reinhardt domain are given in this note.     

RESEARCH ANNOUNCEMENTS Einstein-Khler Metric on Cartan-Hartogs Domain of the First Type

S. Y. Cheng and S. T. Yau showed in [CY] that any C2 bounded pseudoconvex domain in C?has a complete Einstein-Kahler metric with constant negative Ricci curvature. N. Mok and S. T. Yau[MY] have extended this result to arbitrary bounded pseudoconvex domain in Cn. Complete Einstein-Kahler metric with Explicit form, however, is only known in the case of homogeneous domain.     

心钠素

心钠素首先于1983年从大鼠的心房组织中分离得到,但对它的研究可追溯到本世纪50年代。1956年Kisch,1964年,Jamieson先后在哺乳动物心房的心肌细胞中发现存在着一种特殊的分泌颗粒(Atrial specific Gran-