Enantioseparation of Dencichine and D-Isomer on L-Cysteine Derivative Phase by Ligand-exchange Chromatography

Dencichine (β-N-oxalyl-L-α, β-diaminopropionic acid, L-ODAP), a nonprotein amino acid, is a haemostatic agent present in important Chinese medicinal herbs such as Panax notoginseng, as well as other Panax species1. It was first isolated from the seeds …     

利用液晶光阀实现的光学形态变换

提出了基于液晶光阀的光学二值图像领域处理器，利用它完成了扩、蚀和边缘检测等形态变换操作，并给出了实验结果。     

自适应相位制中波同步广播及现场试验

在本试验中，采用智能同步广播激励器和ＣＣＴＶ传输的１ＭＨｚ标频，实现了中波同步广播同频保护率趋于０ｄＢ．并提出了自适应相位跟踪同步的概念。     

介质加载圆柱腔的场分析

本文应用严格场匹配法解决了介质加载圆柱腔的本征问题，计算了圆柱腔在纵向部分填充介质后ＴＥ０１ｎ模和ＴＭ０１ｎ模的本征频率和本征场型的变化。特别分析了本征模式在空气段为截止模的情况。本文的分析方法亦可应用到纵向部分填充介质的传输线和其它形状的谐振腔。     

A dynamic frequency grid allocation scheme for the efficient designof equiripple FIR filters

In the design of a digital filter, the frequency response is often optimized to meet a given set of specifications on a dense grid of frequency points. The density of the frequency grid points must be sufficiently high so that the frequency response of the filter does not violate the specifications at frequencies in between the grid points. However, the computational complexity of the design process and the storage requirements of the computer increase with the number of frequency grid points. We propose a novel dynamic: grid point allocation technique for the design of minimax optimum FIR filter. It uses a sparse frequency grid but will produce a design that is the same as one designed on very dense frequency grid points. It requires significantly less computer time and memory resources compared with fixed grid point algorithms     

受激喇曼散射在掺铒光纤放大器中的影响

本文在分析了均匀掺杂分布式光纤放大器（d－EDFA）的基础上，提出了沿传输方向掺杂浓度单调下降（单变），和降升结合（两变）的两种渐变型分布式光纤放大器，并用传输方程研究了透明传输和最佳掺杂浓度下，受激喇曼散射对均匀、单变和两变型三种d－EDFA的各种特性的影响．     

Performance Optimizations for Deploying VoIP Services in Mesh Networks

In the recent past, there has been a tremendous increase in the popularity of VoIP services as a result of huge growth in broadband access. The same voice-over-Internet protocol (VoIP) service poses new challenges when deployed over a wireless mesh network, while enabling users to make voice calls using WiFi phones. Packet losses and delay due to interference in a multiple-hop mesh network with limited capacity can significantly degrade the end-to-end VoIP call quality. In this work, we discuss the basic requirements for efficient deployment of VoIP services over a mesh network. We present and evaluate practical optimizing techniques that can enhance the network capacity, maintain the VoIP quality and handle user mobility efficiently. Extensive experiments conducted on a real testbed and ns-2 provide insights into the performance issues and demonstrate the level of improvement that can be obtained by the proposed techniques. Specifically, we find that packet aggregation along with header compression can increase the number of supported VoIP calls in a multihop network by 2-3 times. The proposed fast path switching is highly effective in maintaining the VoIP quality. Our fast handoff scheme achieves almost negligible disruption during calls to roaming clients     

Development of a low cost microwave mixer using a broad-band substrate integrated waveguide (SIW) coupler

A low cost single-balanced mixer is designed using a newly designed 90/spl deg/ substrate integrated waveguide (SIW) 3-dB coupler, which takes the advantages of low cost, low profile, and high performance. An X-band single-balanced SIW mixer is designed and fabricated with a standard printed circuit board process. Measured conversion loss of 6.8dB and the wide-band response from 8.5 to 12GHz are presented.     

Series analysis of valid sequences in calculation of synchronisation delay for T-codes

An analysis of the series encountered in Higgie's algorithm of computing average synchronisation delay for T-codes is presented. Convergence for the limiting case of those series is established and an analytical method is developed to verify a result previously found by simulation. These lead to significant improvement in the algorithm, facilitating the search for optimal T-codes for any information source.