图书信息检索中读者兴趣偏好挖掘模型的建立仿真

针对传统挖掘模型对图书信息检索中读者兴趣偏好数据进行挖掘时,存在的挖掘效率低、耗时长等问题,提出基于聚类分析的读者兴趣偏好挖掘模型.采用分类索引分布树法对图书相似度与读者兴趣距离进行计算,通过兴趣因子对兴趣偏好度进行度量,并以此为基础,采用相关反馈模型Rocchio算法对读者兴趣图书检索进行扩展,引入聚类分析法建立图书信息检索中读者兴趣偏好挖掘模型.实验仿真结果表明,采用改进模型时,其挖掘效率、时间及误差均优于传统模型.     

Development of an energy-saving method of resistance projection welding of multilayer welded structures

A highly efficient energy-saving method of resistance projection welding of 3–4 components in a single cycle is described. The method is based on the automatically regulated gradual introduction of electric energy into the zone between the electrodes.     

粉末涂料的颜色测控

介绍了粉末涂料的颜色测量与控制方法,包括颜色测量的基本知识、目测、仪器测量、配色及生产控制,详细介绍了仪器测配色流程,指出做好颜色测控工作必须把仪器测量与人的视觉评判、实践经验等充分结合起来。     

基于语义Web服务的高校学生工作管理系统的服务匹配策略

本文首先介绍语义Web服务匹配研究概况,接着引用基于本体的OWL-S对服务进行语义描述,然后提出基于语义相似度的二级Web服务匹配模型,较好得解决了服务匹配中精确度和复杂度之间的平衡问题。     

提升管中气固两相流动行为的相似特性

在15.1 m高循环流化床实验装置上对提升管内的轴向压力梯度、局部颗粒浓度和颗粒速度进行了较系统的实验测试,研究了提升管中气固两相流充分发展段在不同操作条件下流动行为的相似特性.结果表明,在(G_s /ρ_p)^1.2/U^2.0_g相近的操作条件下,上行气固两相流充分发展段的颗粒浓度、下降颗粒时均速度、絮状物颗粒浓度和出现频率在空间的分布特征基本相同.对于同一提升管内的同一气固两相流系统,只要表观气速和颗粒循环速率按(G_s /ρ_p)^1.2/U^2.0_g同步变化,不同操作条件下的上行气固两相流在充分发展段就具有相似的宏观和微观流动行为.     

Coloration of polypropylene with interference pigment and the effect of wetting agents on its optical properties

Coloration of polypropylene with interference pigment with and without dispersing agents, namely propylene glycol and poly (ethylene glycol) were studied. Effect of pigment concentrations and dispersing agents on various color properties of the molded specimens, such as reflectance versus wavelength characteristics, angular dependency, K/S data, and flop index were evaluated using the CIE system with goniospectrophotometer. Surface image analysis was also conducted. Based on the above parameters, design equations were developed. The study revealed that the effective concentration of the interference pigment was 0.5% and better color characteristics were found when poly (ethylene glycol) was used as a dispersing agent. Presented at the Symposium on Color and Appearance Instrumentation (SCAI), cosponsored by the inter-Society Color Council (ISCC) and the Federation of Societies for Coatings Technology (FSCT), April 15–16, 2003 in Chicago, IL.     

Investigation on interface of NiFeCr/NiFe/Ta films with high magnetic field sensitivity

NiFeCr/NiFe/Ta films with excellent performance were prepared by magnetron sputtering system.The anisotropic magetoresistance (AMR) value (△R/R) and magnetic filed sensitivity (Sv,Sv=[d(△R/R)/dH]max.) for the 12 nm NiFe film deposited on NiFeCr buffer layer were 3.66％ and 1.42 × 10-4 ％T-1,respectively.The higher Sv of the film is close to that of a spin valve (SV).The microstructure analysis shows that the NiFeCr buffer layer has adopted the same structure with the same interplanar distance as the NiFe layer,inducing a strong NiFe (111) texture,and that the NiFeCr/NiFe interface is quite smooth,leading to a high degree of specular reflection of conduction electrons.Both increase the △R and reduce the R in the film,which lead to the high △R/R.Clean substrate surfaces are critical for preparation of high performance NiFeCr/NiFe/Ta films,and sputter cleaning or pre-deposition of 5 nm amorphous A12O3 layer in the deposition chamber can provide the required clean substrate surfaces for the growth of the buffer layer.     

某供弹动力系统泵站容量和蓄能器参数匹配研究

某供弹动力系统是自行研制产品,采用液压储能方案解决高速供弹瞬间大功率输出要求与系统分配的小功率电源之间的矛盾,其泵站容量和蓄能器参数匹配设计是实现节能的关键.为此,利用AMESim软件平台构建机械—液压—控制于一体的供弹动力系统模型,进行液压系统动力学分析,研究泵站容量和蓄能器参数的匹配方法.分析结果表明:在一个工作循环中蓄能器有多次充、放油过程,以系统平均耗油的0.7～0.8倍作为泵站容量,适当提高系统最高压力(0.6～0.8 MPa),以蓄能器油腔容积变化的最大范围和小压差确定蓄能器参数,可稳定蓄能器连续供油速率,保证系统及时供弹,达到节能目的.     

基于即时学习算法的铸坯质量预测方法

传统铸坯质量预测大多基于全局建模方法,存在自适应能力较差、预测精度不稳定等不足。为此,提出了一种基于即时学习算法的铸坯质量预测方法,主要特征为构建基于即时学习算法的局部模型,以取代传统全局模型,实现建模和预测同时在线进行,更适应于场景复杂、工况多变的连铸生产过程;根据连铸生产数据的时变性特点,在相似度计算中引入时间权重因子,强化样本数据与待测数据的相关性,更有利于提高铸坯质量预测模型精度。以国内某钢厂65号高碳钢铸坯三角区裂纹为例,具体说明即时学习算法在铸坯质量预测局部模型构建中的应用,并与铸坯质量预测全局模型的预测结果进行对比分析及评价。结果表明,基于即时学习算法的局部模型在评价指标上均优于全局模型,全局模型的预测准确率为65%,基于即时学习算法的局部模型准确率提升至90%,进一步阐明基于即时学习算法的局部模型用于铸坯质量预测的有效性。