TiO2掺杂SmTaO4陶瓷热物理性能研究

热障涂层是燃气轮机高温部件保护的重要材料之一,SmTaO4陶瓷具有优异的高温相稳定性和力学性能,有望成为新型热障涂层材料。本研究采用固相法制备TiO2掺杂SmTaO4陶瓷,研究结果表明：掺杂TiO2未改变SmTaO4陶瓷晶体结构,样品均为单斜相,掺杂2% mol TiO2的SmTaO4陶瓷烧结过程中出现的第二相为Sm0.33TaO3;随着TiO2含量增加,SmTaO4陶瓷的热导率先下降后上升,当TiO2掺杂含量为2%时,热导率最低为1.42W?m?1?K?1,低于SmTaO4（1.59W?m-1?K-1,900℃）,与7-8YSZ相比（2.1~2.7 W?m?1?K?1,100~900℃）下降了近30%。掺杂2%TiO2的SmTaO4陶瓷热膨胀性系数最大值为10.8×10-6K-1,大于YSZ（~10.0×10-6K-1）和SmTaO4（9.62×10-6K-1,1200℃）,与纯SmTaO4相比,TiO2掺杂提高了SmTaO4陶瓷的热膨胀系数。因此,TiO2掺杂SmTaO4陶瓷有望作为新型热障涂层材料使用。     

巡检机器人机械臂空间变形解析模型分析

根据高压输电线路检测环境,提出一种高压输电线路巡检机器人.以该输电线路巡检机器人为研究对象,采用Denavit-Hartenberg法建立巡检机器人的连杆坐标系,推导巡检机器人的变换矩阵.并应用微分变换法推导巡检机器人的雅可比矩阵,得到操作空间外力(速度)与关节空间内力(速度)的线性映射关系.机器人操作臂的刚度影响整个...     

SVM方法在火箭发动机故障预测中的应用研究

为了实时、准确、可靠地预测液体火箭发动机故障,在分析标准支持向量机回归方法(SVR)和最小二乘支持向量机回归估计法(LS-SVR)特点的基础上,建立了液体火箭发动机故障预测模型,并分别将其应用于液体火箭发动机参数预测问题。研究结果表明:SVR和LS-SVR两种方法都能有效解决液体火箭发动机故障预测过程中的非线性、高维数、小样本、局部极小等问题。     

基于拉式生产模式的企业人力资源需求分析

拉式生产是采用订单生产的方式,这样可以有效地减少仓储的成本。但是订单的不确定性给企业的生产带来了新的问题——企业如何确定自己的生产能力？文中通过对订单分析,并结合企业效益以及潜在损失来确定企业的生产能力,并进一步分析了生产人员的需求。     

Preparation,properties, and applications of acrylic–polyurethane hybrid emulsions in extinction electrophoresis

Aqueous acrylic–polyurethane hybrid emulsions (PUA) were fabricated by semibatch emulsion copolymerization using a mixture of acrylic (AC) monomers in the presence of an isocyanate terminated polyurethane (PU). The effects of PU content on the morphology of the hybrid emulsions and film properties were here investigated in detail using FT‐IR, UV, TEM, and SEM. TEM images clearly showed that hybrid emulsions exhibited a core‐shell structure before neutralization. However, after neutralization with N,N‐dimethylethanolamine, the typical particles exhibited phase inversion, producing particles with irregular hemispheres shapes and diameters about 0.5 μm. SEM images showed that the film surface became rougher as PU content increased, peaking at 10 wt %, the gloss of this film was 23.1 (60°). The UV transmittance spectra of the PUA hybrid emulsion within a wavelength range 700–200 nm decreased as PU content increased. This was consistent with the changes in the surface roughness of the film. Electrophoresis took place on an aluminum alloy surface and the product was dried at 120°C. The film exhibited excellent mechanical performance due to curing reaction between the N?C?O group on PU and hydroxyl group on the AC copolymer. The gloss of the film was found to be as low as 4.0 after electrophoresis testing. These films may be useful in practical extinction electrophoresis. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40078.     

任意位姿物体机器视觉测量视差变形补正

提出一种对机器视觉测量视场内任意位姿目标物体视差变形导致测量误差进行物体自动跟踪和变形补正的方法。在分析视差变形基础上,提出自动跟踪检测模型,得出补正参数。通过改进的序贯相似性检测算法(SSDA)模板匹配、图像的二值化处理和腐蚀、质心坐标求取和轮廓边缘搜索等计算,计算出反映目标物体位置、姿态偏移的特征参数,从而求得目标物体自动跟踪位置、姿态偏移补正量。以任意位姿M4螺母内螺纹检测为实验对象,实验结果表明,该自动跟踪补正方法可行,具有较好的跟踪一致性,取得了较好的视差变形补正效果。     

Elastoplastic contact mechanics model of rough surface based on fractal theory

Because the result of the MB fractal model contradicts with the classical contact mechanics, a revised elastoplastic contact model of a single asperity is developed based on fractal theory. The critical areas of a single asperity are scale dependent, with an increase in the contact load and contact area, a transition from elastic, elastoplastic to full plastic deformation takes place in this order. In considering the size distribution function, analytic expression between the total contact load and the real contact area on the contact surface is obtained. The elastic, elastoplastic and full plastic contact load are obtained by the critical elastic contact area of the biggest asperity and maximun contact area of a single asperity. The results show that a rough surface is firstly in elastic deformation. As the load increases, elastoplastic or full plastic deformation takes place. For constant characteristic length scale G, the slope of load-area relation is proportional to fractal dimension D. For constant fractal dimension D, the slope of load-area relation is inversely proportional to G. For constant D and G, the slope of load-area relation is inversely proportional to property of the material ϕ, namely with the same load, the material of rough surface is softer, and the total contact area is larger. The contact mechanics model provides a foundation for study of the friction, wear and seal performance of rough surfaces.     

离子液体复配溶液吸收CO_2的研究进展

综述了近年来国内外利用离子液体吸收CO2的研究状况,重点分析了离子液体-水复配溶液和离子液体-有机胺复配溶液吸收分离CO2的特点及其机理,讨论了温度、压力、配比、特殊基团等相关影响因素对脱碳过程的影响。对尚存在的问题提出建议,并对前景做了展望。     

蠕动进给超声磨削ZrO_2陶瓷实验研究

建立了超声磨削在小直径磨轮、大切深、蠕动进给条件下单颗磨粒最大切深模型; 对ZrO2陶瓷进行蠕动进给机械磨削和蠕动进给超声磨削对比试验, 考察了磨削参数对磨削力的影响.实验结果表明: 超声振动可减小磨削力.     

梨形针自动化加工研究

作为喷丝板微孔的精整工具,梨形针对喷丝板的生产有极其重要的作用。根据梨形针的形状尺寸,利用机器视觉系统设计了自动加工梨形针的光机电一体化装置,实现了梨形针的自动化加工以及形状尺寸的在线实时检测,其加工精度可达±3μm。与传统手工加工方法相比,该装置提高了梨形针加工自动化程度,保证了加工尺寸的一致性,操作简单易行。