Tuning fuzzy power-system stabilizers in multi-machine systems by global optimization algorithms based on efficient domain partitions

In this paper, the problem of global tuning of fuzzy power-system stabilizers (FPSSs) present in a multi-machine power system in order to damp the power system oscillations is considered. In particular, it is formulated as a problem of global minimization of a multiextremal black-box function over a multidimensional hyperinterval. A global optimization technique, recently proposed, is used for solving the stated problem: the search hyperinterval is partitioned into smaller hyperintervals and the objective function is evaluated only at two vertices corresponding to the main diagonal of the generated hyperintervals, thus avoiding unnecessary ponderous simulations. Then, the performances of this technique are numerically compared with ones of a genetic algorithm (GA).     

Hybrid numerical scheme for time-evolving wave fields

Many problems in geophysics, acoustics, elasticity theory, cancer treatment, food process control and electrodynamics involve study of wave field synthesis (WFS) in some form or another. In the present work, modelling of wave propagation phenomena is studied as a static problem, using finite element method and treating time as an additional spatial dimension. In particular, WFS problems are analysed using discrete methods. It is shown that a fully finite element-based scheme is very natural and effective method for the solution of such problems. Distributed WFS in the context of two-dimensional problems is outlined and incorporation of any geometric or material non-linearities is shown to be straightforward. This has significant implications for problems in geophysics or biological media, where material inhomogeneities are quite prevalent. Numerical results are presented for several problems referring to media with material inhomogeneities and predefined absorption profiles. The method can be extended to three-dimensional problems involving anisotropic media properties in a relatively straightforward manner. Copyright © 2006 John Wiley & Sons, Ltd.     

基于单片机技术的机械设备计时器的研制

介绍一种基于单片机和振动传感器技术，采用软、硬件结合设计的新型数字式机械设备计时器，分析了原理、硬件结构、技术方法、配套设备和软件功能。     

测尘仪原理与应用

本文介绍了测尘仪器的基本原理,着重阐述了透射法和散射法的基本原理和实际应用.     

节能建筑中人体传热模型和计算公式

讨论人体新陈代谢发热率及其影响因素;论述节能建筑中舒适的环境温度、空气相对湿度、空气流速以及新鲜空气供给量的最佳值范围;同时考虑皮肤和肺部的显热散热和蒸发潜热散热,建立了传热模型,得出了计算公式。     

空气钻井条件下录井工艺方法与技术配套探讨

针对玉门青西油田深部高陡易斜地层存在可钻性差、自然造斜能力强，致使钻井周期长、成本高等特点，中油集团公司在吐哈油田设立钻探“工程探索井（L14井）”重大科研项目，试验研究空气钻井技术。根据L14井录井的实际情况，首先分析了空气钻井条件对录井带来的影响和常规的录井工艺方法和技术设备存在的不足；从5个方面介绍了录井工艺、技术方法的改进，探讨了空气钻井下的岩屑上返理论；介绍了配置装备的改进，分析了该井录井配套技术的应用效果。从该试验井的录井效果看，经改进的录井工艺、方法及装备基本上能满足空气钻井的需要，取全取准了地质及工程资料，为地质解释和评价提供了可靠依据；在工程监测、保障施工安全方面，工程录井也发挥了作用。但综合录井仪软件及后台评价程序还不适应空气钻井的需要，相关的理论研究及工艺完善还有许多课题尚需深入。     

聚合物分解法制备微波介质陶瓷粉体的研究

对采用聚合物分解（Ｐｅｃｈｉｎｉ）法制备ＭｇＴｉＯ＿３粉体进行了研究。通过对聚合中间产物进行红外光谱分析，研究了聚合物分解法制备ＭｇＴｉＯ＿３陶瓷粉体的聚合反应过程及产物。并与用传统固相反应法制备粉体工艺进行对比．从而证明用聚合物分解法可获得单一ＭｇＴｉＯ＿３相材料．并可降低粉体的煅烧温度。     

管内覆丝网强化对流换热及阻力特性的实验研究

通过实验对管内覆丝网管进行了强迫对流换热和阻力特性研究。结果表明：管内覆丝网使换热明显增强，阻力也相应增长。菱形丝网对角线距离与平行边距离之比对换热效果有决定作用，丝网厚度对换热的影响比较小，而丝网网格的大小对换热几乎没有影响，在相同的泵功率和几何条件下，换热系数最大增加２１％。     

铸铝激光熔融处理后的组织与性能

应用光学和电子显微镜及显微硬度计研究了铸造Al-Si合金经激光表面熔融处理后的组织和性能。指出,组织分熔化区、过度区和基体三层。在熔化区中树枝状先共晶α相的平均宽度由原始组织的20～40μm细化到2～3μm,同时共晶组织也被大大细化。这些变化使显微硬度值由67.4提高至109～115.     

强度调制型光纤传感器信号补偿技术的现状与应用

简要地介绍了强度调制光纤传感器的特点,着重分析和比较目前国内外五种有代表性的强度调制型光纤传感器信号补偿方法及其应用状况.