Recursive algorithms for deriving bandpass or band-rejection filters from lowpass filters

Two recursive algorithms are presented for calculating the coefficients of a bandpass transfer function, given the lowpass prototype transfer function. In both cases, the method is general, valid for prototypes having both poles and zeros, and provides excellent accuracy. Moreover, it is shown that the coefficients of band-rejection filters can be derived by using either algorithm.<>     

Direct optical injection locking of 20 GHz superlattice oscillators

For the first time, a direct optically injection-locked oscillator based on the Esaki-Tsu effect in superlattices is reported. The microwave output power is -7 dBm at 20 GHz with an optical input power of -10 dBm at a wavelength of 1.3 μm     

A novel dynamic survivable routing in WDM optical networks with/without sparse wavelength conversion

In this paper, we study the dynamic survivable routing problem, both in optical networks without wavelength conversion and in optical networks with sparse wavelength conversion, and propose a novel hybrid algorithm for it based on the combination of mobile agents technique and genetic algorithms (GA). By keeping a suitable number of mobile agents in the network to cooperatively explore the network states and continuously report cycles (that are formed by two disjoint-link routes) into the routing tables, our new hybrid algorithm can promptly determine the first population of cycles for a new request based on the routing table of its source node, without the time consuming process associated with current GA-based lightpath protection schemes. We further improve the performance of our algorithm by introducing a more advanced fitness function that is suitable for both the above networks. Extensive simulation studies on the ns-2 network simulator show that our hybrid algorithm achieves a significantly lower blocking probability than the conventional survivable routing algorithms for all the cases we studied.     

Design and Manufacture of GeSi/Si Superlattice Nanocrystalline Photodetector

According to Maxwell＇s theory, the optical transmission characteristics in GeSi/Si superlattice nanocrystalline layer have been analyzed and calculated. The calculated result shows that when the total thickness L is 340 nm, the single mode lightwave can be transmitted only at periodic number M≥15.5. In addition, at the direction of transmission, when the transmission distance is larger than 500 μm, the lightwave intensity is decreased greatly. Based on the above parameters, the design and manufacture of GeSi/Si superlattice nanocrystalline photodetector are carried out.     

变温条件下HDPE/CB的正电子湮灭特性

对掺杂了25份（phr）导电炭黑（CB）的样品进行了正电子湮灭寿命谱的变温测量，在玻璃化转变温度以上，随着温度的增加，自由体积的大小线性增加，在玻璃化转变温度以下，自由体积的大小基本不变，o-Ps的强度在－40℃下基本不变，从－40℃以上开始增加，但在50℃以上上升有加快的趋势，与PTC材料的PTC现象和导电性能有一定的关联。     

包钢选矿厂降低铁精矿中氟含量的技术攻关

为了降低铁精矿氟含量,通过采取控制磨矿粒度、改进浮选工艺、采用高效捕收剂等措施,使包钢选矿厂铁精矿氟含量由1999年的0.75%降低到2000年的0.65%、2001年的0.58%,为包钢环保工作目标的完成做出了突出贡献.     

ZnS掺杂技术研究及应用现状

对现阶段国内外在ZnS及ZnS基材料掺杂改性方面的研究成果作一概述性介绍，综述了纳米级ZnS发光材料掺杂改性的基本机理，主要的掺杂技术、方法，并对多种掺杂元素的效果进行了分析比较。     

Contribution a l'etude du polymorphisme de Ga2S3: Structure cristalline de Mn0,23Ga1,85S3

The Mn_0.23Ga_1.85S₃ phase belongs to the solid solution $\text{ф}{}_0$, stable at low temperature in the Ga₂S₃MnS system. It is hexagonal superstructure of the wurtzite, with the Ga₂S₃α′ type ($\text{a}\text{= 6.397}\text{A}\text{?}$; $\text{c}\text{= 18.027}\text{A}\text{?}$Z = 6; space groupe P6₁ or P6₅). Its crystal structure has been refined by the least squares method to a final R = 0.06 with 323 independant reflections. This structure is closely related to Ga₂S₃ α described by Hahn and Frank, and differs only by the partial occupation of the vacant metal site of Ga₂S₃ by Mn atoms in statistical disorder.