RFRA算法在移动机器人磁罗盘定位中的应用研究

磁罗盘是一种可以用于移动机器人定位的重要传感器。该文介绍了移动机器人磁罗盘定位系统中TS模糊模型的构建、鲁棒模糊回归聚类算法RFRA的基本框架与实现,并在实验中验证了这种算法的性能。     

协同演化算法研究进展

协同演化算法(coevolutionary algorithms,CEA)是当前国际上计算智能研究的一个热点,它运用生物协同演化的思想,是针对演化算法的不足而兴起的,通过构造两个或多个种群,建立它们之间的竞争或合作关系,多个种群通过相互作用来提高各自性能,适应复杂系统的动态演化环境,以达到种群优化的目的.介绍了协同演化算法的研究状况以及目前的研究进展,概述了它的基本算法、主要特点、理论与技术,同时介绍了一些主要的应用领域,指出了协同演化算法的研究方向.     

PIECEWISE LYAPUNOV FUNCTIONS FOR SWITCHED SYSTEMS WITH AVERAGE DWELL TIME

The stability properties of linear switched systems consisting of both Hurwitz stable and unstable subsystems are investigated by using piecewise Lyapunov functions incorporated with an average dwell time approach. It is shown that if the average dwell time is chosen sufficiently large and the total activation time ratio between Hurwitz stable and unstable subsystems is not smaller than a specified constant, then exponential stability of a desired degree is guaranteed. The above result is also extended to the case where nonlinear norm‐bounded perturbations exist.     

Application of empirical electron theory of solids and molecules to composition design of multi-component medium-low-alloy steels

For austenitic octahedral segregation structure units, their pure mathematics statistic distributive probability is calculated by the empirical electron theory (EET) of solids and molecules and K-B formula. The practical distributive probability can be obtained only if the statistic distribution of austenitic octahedral segregation structure units and the interaction of the alloying elements in steel are considered. Based on 8 groups of experimental data of original steels, three empirical formulas revealing relationships between material macromechanics factor (Sm) and tensile strength (σb), or impact energy (AK), or hardness (HRC) of multi-component medium-low-alloy steels were established, respectively. Through the three empirical formulas, new supersaturated carburizing steel has been successfully designed and developed. The other 2 groups of the original experimental steels are used as the standard steel for testing the percentage error of the new steel. The results show that the calculated values are well consistent with those of measured ones and the new supersaturated carburized steel can meet the requirements of the die assembly of cold-drawn seamless stainless steel tube of Taiyuan Iron & Steel (Group) Company LTD.     

基于非对称贴近度的水库移民后期扶持效果评价模型研究

国家对大中型水库移民实行前期补偿加后期扶持的政策,后期扶持工作是帮助移民重建社会和经济关系的系统工程。对于后期扶持政策的实施效果评价,目前多采用基于最大隶属度原则的模糊综合评判法。但该方法在应用过程中可能会丢失大量信息,从而引起评价结论失真。非对称贴近度方法能够在一定程度上避免最大隶属度原则的缺陷。本文首先结合文献和专家意见建立后期扶持效果评价指标体系,利用层次分析法确定指标权重,在此基础上构建基于非对称贴近度的移民后期扶持效果评价模型,并将其应用于龙门县大中型水库移民后期扶持政策实施效果评价。实例分析表明,该模型能客观地反映当地移民后期扶持的效果并揭示不足之处,评价结果较为可信、合理,可为水库移民后期扶持工作实践提供参考。     

热塑性导电塑料在屏蔽电磁波干扰中的应用

介绍了复合型导电塑料，特别是导电纤维增强热塑性塑料在屏蔽电磁波干扰中的应用现状和技术发展趋势，讨论了3种主要的导电纤维即碳纤维，镀镍碳纤维和不锈钢纤维的优缺点；比较了不同的加工设备和加工方法对这类导电复合材料性能的影响。     

Studies on novel composites of polyoxymethylene/ polyamide 6

A series of new composite of polyoxymethylene/polyamide 6 (POM/PA 6) were synthesized by using ε‐caprolactam as a reactive solvent with POM soluble in it. Incorporating a small content of POM (1–4 wt %) into PA 6 led to a great improvement of impact resistance POM/PA 6. The effects of POM content on the mechanical, morphological, and thermal properties of the composites were investigated. Incorporating minor POM (1 wt %), disposed in finely dispersed level (about 1 μm), into PA 6 matrix can greatly reduce the crystallization rate and crystallinity of PA 6. Scanning electron microscopy measurements indicated that much microfibers with aspect ratio about 10 appeared with the addition of 3 wt % POM because of the change of phase separation mechanisms. As a result, with a small content of PA 66 (1–4 wt %) incorporated, the impact strength and elongation of POM/PA 6 were improved markedly, with retention of good tensile strength. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 335–339, 2006     

Crystallization behavior of nylon 11/montmorillonite nanocomposites under annealing

Exfoliated nylon 11/montmorillonite (MMT) nanocomposites were prepared via in situ polymerization by the dispersion of organically modified MMT in 11‐aminoundecanoic acid monomer. The polymorphic behavior of the nylon 11/MMT nanocomposites was investigated with X‐ray diffraction, transmission electron microscopy, and Fourier transform infrared with attenuated total reflectance. MMT induced and stabilized the δ‐crystalline form of nylon 11. The crystal structure of nylon 11 was transformed from a hexagonal δ‐form structure to a triclinic α‐form structure during the annealing process. Meanwhile, the hydrogen bonds in the nanocomposites also exhibited some differences from neat nylon 11 after annealing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5483–5489, 2006     

地震影响下西南干旱山区泥石流危险性特征与防治对策

"5·12"汶川大地震后,中国西南地区积累了大量的松散堆积物,在强降雨作用下,这些松散堆积物容易启动产生泥石流.2010年中国西南地区更是经历了罕见的旱灾,长历时的干旱易引发强烈的森林火灾,后期易形成更强的降雨,同时,在干旱作用下,松散堆积物中的黏土颗粒收缩,在降雨作用下会迅速吸水膨胀,阻塞土体空隙,使孔隙水压力迅速增大,土体抗剪强度随之降低,更易启动产生泥石流.此文在历史上泥石流危险性特征的基础上,结合地震活动规律与干旱区分布特征,进行泥石流危险区划分,并在此基础上提出防控建议.