悬锤式小巧光电测角仪

本文给出一种基于微型光电编码器和８９Ｃ２０５１ 单片机的数字显示的小巧测角仪。其创新点在以重锤杆做为转动角度的基准线; 并用磁吸合方式与被测体固定。该仪在一些场合应用特别方便     

Excess volumes and excess viscosities of binary mixtures of some cyclic ethers + bromocyclohexane at 298.15 and 313.15 K

Excess Volumes,V ^E, and excess viscosities, ^E, at 293.15 and 313.15 K are reported for binary mixtures of some cyclic ethers (tetrahydrofuran, tetrahydropyran, 2-methyltetrahydrofuran and 2,5-dimethyltetrahydrofuran) + bromocyclohexane. These properties were obtained from density and viscosity measurements. ^E and ^E show negatives values for all the mixtures.     

一种用于入侵检测的改进人工免疫算法

通过对基于信息熵和基于欧氏距离的免疫算法的分析和改进,提出一种新的适用于入侵检测的人工免疫算法（AIAID）。该算法引入马氏距离的思想,改进相似度和期望繁殖率的计算,把抗体不同特征的重要性和取值范围加入到相关运算中,对算法流程进行优化。设计一种新的基于AIAID的入侵检测系统模型。实验表明,将AIAID用于入侵检测能够明显缩短训练时间,提高检测效率。     

改进邻居集合的个性化推荐算法

协同过滤算法是目前个性化推荐系统中应用最成功的推荐算法之一,但传统的算法没有考虑在不同时间段内寻找最近邻居问题,导致寻找的邻居集合可能不是最近邻居集合。针对此问题,提出一种改进邻居集合的个性化推荐算法。该算法赋予每项评分一个按时间逐步递减的权重,利用加权后的评分寻找目标用户的最近邻居。实验表明,改进的算法提高了推荐系统的推荐质量。     

Optimal replacement policy for a two-dissimilar-component cold standby system with different repair actions

In this paper, a cold standby repairable system consisting of two dissimilar components and one repairman is studied. When failures occur, the repair of both component 1 and component 2 are not ‘as good as new’. The consecutive operating times of component 1 after repair constitute a decreasing geometric process, while the repair times of component 1 are independent and identically distributed. For component 2, its failure is rectified by minimal repair, and the repair time is negligible. Component 1 has priority in use when both components are good. The replacement policy N is based on the failure number of component 1. Under policy N, we derive the explicit expression of the long-run average cost rate C(N) as well as the average number of repairs of component 2 before the system replaced. The optimal replacement policy N*, which minimises the long-run average cost rate C(N), is obtained theoretically. If the failure rate r(t) of component 2 is increasing, the existence and uniqueness of the optimal policy N* is also proved. Finally, a numerical example is given to validate the developed theoretical model. Some sensitivity analyses are provided to show the influence of some parameters, such as the costs for replacement and repair, and the parameters of the lifetime and repair time distributions of both components, to the optimal replacement policy N* and corresponding average cost rate C(N*).     

Transport properties of nonelectrolyte liquid mixtures—IV. Viscosity coefficients for benzene,perdeuterobenzene, hexafluorobenzene,and an equimolar mixture of benzene + hexafluorobenzene from 25 to 100°c at pressures up to the freezing pressure

Viscosity coefficient measurements made with an estimated accuracy of ±2% using a self-centering falling body viscometer are reported for benzene, perdeuterobenzene, hexafluorobenzene and an equimolar mixture of benzene + hexafluorobenzene at 25, 50, 75 and 100°C at pressures up to the freezing pressure. The data for each liquid at different temperatures and pressures are correlated very satisfactorily by a graphical method based on plots of 9.118×10⁷ V ^2/3/(MRT)^1/2 versus logV, and are reproduced to within the experimental uncertainty by a free-volume form of equation. Application of the empirical Grunberg and Nissan equation to the mixture viscosity coefficient data shows that the characteristic constant G is practically temperature- and pressure-independent for this system.     

熔体流动时间法测定PBT树脂特性粘数的研究

开发了一种新的特性粘数分析方法 ,该方法采用熔体流动时间计算特性粘数 ,与经典特性粘数分析方法有很好的相关性且具有分析时间短、费用低、无污染等优点。     

模糊综合评价法在长江下游贵池河段水质评价中的应用

对水质评价存在诸多方法,而模糊综合评价法具有评价结果合理、更接近客观实际等优点,因而得到越来越广泛的应用。通过模糊评价方法对长江下游贵池河段2005～2009年间水环境综合评价,并采用加权平均原则求取隶属等级,取得较好的效果。     

我国超高分子质量聚乙烯纤维的检测手段及发展现状

根据国内主要超高分子质量聚乙烯纤维制造商产品的测试结果,论述了国产该纤维的主要性能及其与国外同类产品的质量差距,论述了目前我国各生产厂家及相关检测机构在强度、模量、断裂伸长、耐磨性、蠕变率、分子质量等纤维主要性能测试中存在的问题,提出了解决建议,同时指出了我国在超高分子质量聚乙烯纤维应用方面与国外的差距．     

基于遗传算法的关联议题并发谈判

基于遗传算法的并发谈判在电子商务应用中具有独特的优势,但已有的研究尚未考虑议题之间的相关性、动态权重的变化规则依赖于对手信息的获取,极大地限制了其使用价值.对此,提出议题分组的方法以解决议题的相关性问题,而议题权重的变化则采取从历史资源中发掘知识的方法进行动态调整.构建了基于遗传算法的关联性议题并发谈判模型,给出了模型的形式化描述、谈判算法设计和动态权重更新方案.通过对模型的实验和比较分析,证实了该方案能够更方便地满足用户谈判的多样性需求,解决谈判中议题关联性的问题,而且能够快速、有效地得出最优谈判结果.