一种新颖的超结构光纤Bragg光栅梳状滤波器的设计

报道一种新颖的用于多波长光纤激光器的超结构光纤Bragg光栅（SFBG）梳状滤波器，其突出特点是仅由单个光栅构成、折射率调制和局部啁啾富于变化、反射峰均匀性好、窄带宽和标准的信道间隔.采用基于LP算法的IS光纤光栅设计技术，将整体加窗切趾法改进为各信道独立加窗切趾，成功地设计出所需的SFBG，同时对SFBG的制作技术也进行了探讨.用传输矩阵法分析反射谱、时延曲线和群时延抖动.结果表明，所设计的SFBG满足各项设计指标要求，在DWDM系统中，这种新颖的SFBG可望成为用于多波长光纤激光器的最理想的高性 能梳 关键词： 超结构光纤Bragg光栅 光栅设计 梳状滤波器     

Synthesis of acetone oxime through acetone ammoximation over TS-1

The ammoximation of acetone to acetone oxime with 30 wt.% hydrogen peroxide over TS-1 has been studied. The conversion of acetone and the selectivity to acetone oxime can reach 99% and 94%, respectively. The by-products are the corresponding hydrazone, imine and small amounts of unidentified compounds. The influence of various parameters such as solvent, temperature, amounts of catalyst and the NH₃ to acetone molar ratio were investigated. This revised version was published online in August 2006 with corrections to the Cover Date.     

将SVRT模型应用到单原子多原子反应F+CH2D2→CH2D/CHD2+DF/HF中

由于含时波包方法具有经典的直观又不乏量子力学的准确 ,选择含时波包方法来处理F +CH2 D2 →CH2 D/CHD2 +DF/HF反应 .把半刚性振转子 (SVRT)模型应用到该反应体系中 ,研究了两个通道中该反应从基态反应物开始在修正过的J1(MJ1)势能面上计算出来了反应几率、积分截面、速率常数 .反应几率随能量变化的图的数值结果给出了振荡结构 ,这些振荡结构是可以和动力学振荡联系起来的 .而这些振荡结构在积分截面随着能量变化的图中就被反应几率求和后的平均结果所掩盖了 .速率常数和实验结果的比较也得到了较好的结果 .     

Electronic structures and ferroelectric properties of ABi2Ta2O9 (A=Ca, Sr, and Ba)

The electronic structures of ABi₂Ta₂O₉ (A=Ca, Sr, and Ba) were calculated by using first-principles under optimized structure. As the size of A-site cation decreases from that of Ba²⁺ to Ca²⁺, the band-gap between O 2p and Ta 5d increases from 2.0 to 2.9 eV, which responses to the stronger orbital hybridizations between Ta 5d and O 2p orbits favoring improvement of the ferroelectric property, decrease in leakage current, and increase in both spontaneous polarization and Curie temperature by the structural distortion. In contrast to CaBi₂Ta₂O₉ and SrBi₂Ta₂O₉, the hybridization between Ba 5p orbits and O 2p orbits in BaBi₂Ta₂O₉ has better structural stability.     

基于人工神经网络的商业银行信用风险模型

在对人工神经网络的基本原理进行简要介绍的基础上 ,着重对构建商业银行信用风险的人工神经网络模型进行了研究 ,实证结果表明 ,人工神经网模型具有很高的预测精度     

Molybdenum nitride fibers or tubes via ammonolysis of polysulfide precursor

Millimeter-sized molybdenum nitride (MoN), in the forms of fiber-like prisms or hollow tubes, has been successfully synthesized via thermal ammonolysis of molybdenum polysulfide precursor. The initial morphology of the precursor is well preserved in the final product. This method could be expanded to preparation of other fiber-like nonmetal ceramics without addition of template. The polysulfide precursor (abbreviated to PS), hydrothermally prepared at 30°C (PS1) or 150°C (PS2), was characterized by various methods for better comprehension of the sulfide-nitride topotactic conversion model.     

企业信息化中的网络存储整合应用

首先介绍了网络存储技术中NAS技术和SAN技术的基本原理,并对两者的特性进行了比较;然后详细介绍了企业信息化过程中网络存储整合的一个典型案例,分析了其整合前存在的不足,制定有效的整合实施方案,并对实施过程中许多关键技术部分进行了阐述,最终很好的达到了预定目标;最后总结了网络存储整合需要规划多种技术相融合的必要性.     

Study on a Distributed Wavelength Routing Algorithm in WDM Optical Transport Networks

A new design scheme for a distributed algorithm for routing and wavelength assignment (RWA) is developed in this paper, and the communication rules between the nodes to exchange signaling packets are discussed. The Adaptive-Alternate-Routing-Least-Load (AARLL) algorithm is implemented in the distributed scheme for the first time. Under dynamic traffic circumstances, the influence of the race condition, which does not exist in centralized scheme, on the network performance is analyzed and the analyzed results show that the race condition has a major impact on network performance only under light traffic load, while under medium and heavy traffic load the impact is very small. To analyze the performance loss caused by adopting the distributed algorithm for RWA, the capacity loss factor (CLF) is introduced and the calculated results show that CLF does not exceed 6% under medium traffic load.     

一种基于循环小波累积量的谐波恢复方法

循环统计量是乘性和加性噪声中谐波恢复问题的主要分析工具之一。本文在其基础上提出了一种新的理论与方法——基于循环小波累积量的谐波恢复方法。首先,提出了循环小波累积量的定义。然后,建立了基于一阶、二阶、三阶循环小波累积量的谐波分量的频率和相位的估计方法。在此基础上,采用了一种可调参数的小波,通过调节其参数来改善传统方法中频率分辨率低的缺陷。最后给出了模拟实验结果。