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     

国内外压力容器标准对射线透照检测要求的对比分析

对欧美压力容器标准与GB 150—1998中对射线透照检测要求进行了对比分析,并结合中国的压力容器标准及行业发展现状,对GB 150—1998标准中相应条款提出了修订建议。     

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.     

煤矿水害防治不精确推理模型的建立

采用基于可信度的方法建立了煤矿水害防治的不精确推理模型,并给出了该模型中不同规则的不确定性传播的算法,为建立煤矿水害防治专家系统提供了基础.     

可见光共振腔发光二极管的研究进展

共振腔发光二极管是一种具有优良发光性能的光电器件。概述了对可见光共振腔发光二极管的共振腔结构、反射镜材料体系、基本工作机理和发光特性，并展望了这种器件的发展前景。     

高强铝合金断裂韧性的研究现状及展望

通过对三种裂纹模式的概述，引出了铝合金断裂韧性的概念及断裂判据，重点评述了影响高强铝合金断裂韧性的内在与外在因素，以及断裂韧性与其它力学性能间的关系，最后提出了几个在今后的研究及应用中需要重点解决的问题。     

网格曲面中孔洞的光滑填充算法研究

三角网格模型是几何描述的一种重要形式，有着广泛的应用。但三角网络模型常常会存在孔洞缺陷。这些孔洞的存在一方面影响视觉效果，另一方面会影响许多后续的操作，如快速原型制造、有限元分析等，因此有必要对这些孔洞进行修补。目前绝大多数孔洞填充算法是将网格模型中的孔洞提取成空间多边形，并对孔洞多边形进行三角化。这种处理方法的主要缺陷是没有考虑网格曲面在孔洞附近的几何形态，因而填充部分不能与整个曲面光滑地融为一体。笔者提出了一种三角网格曲面中孔洞的光滑填充算法。该算法根据孔洞周围网格曲面的几何信息来增加孔洞内部的采样点，然后再对增加的采样点进行三角化，较好地解决了填充部分与整体曲面光滑连接的问题。     

关于最远点判定及直径的唯一性

给出了点到有界集最远点的一些必要或充分条件，然后对直径的唯一性也给出了一些判定条件。