Sn-Bi系低温无铅钎料的研究现状与展望

锡铋钎料是近年来比较有发展潜力的低温无铅钎料,其广泛应用于低温钎焊相关产业中。锡铋钎料中Bi的脆性、 Sn-Bi钎料在服役过程中出现相的粗化以及Sn-Bi/Cu焊点Bi在界面偏聚等问题一直以来是国内外学者争相研究的热点。文中结合国内外对Sn-Bi钎料的最新研究成果,主要阐述了Ag, Cu, Zn, Sb, Ni等5个元素对Sn-Bi钎料的熔化特性、力学性能、润湿性以及钎焊点显微组织和性能等方面的影响,指明了不同成分的钎料在目前研究中存在的问题及今后研究的方向。     

锌冶炼铅银渣还原焙烧挥发铅锌试验研究

研究了铅银渣还原焙烧挥发铅、锌,考察了升温制度、焙烧温度、焙烧时间、焦粉用量、添加剂用量等对铅锌挥发率的影响。结果表明:在1 200℃下恒温焙烧60 min,控制焦粉用量40%、添加剂氧化钙用量4%,铅、锌挥发率分别高达98.85%和97.6%,挥发效果较好。     

关于汽车尾气成分动态检测技术的分析

动态检测技术,是汽车尾气成分分析的新方法,它具有基础性、检测性以及服务性等特征。基于此,本文结合技术设计的相关原理,着重分析检测技术应用要点,以达到彰显汽车生产技术优势,实现城市环境优化的目的。     

燃气轮机试验台水力测功器系统设计

基于ENN1500燃气轮机试验台建设,讨论了水力测功器的特性曲线,给出了水力测功器的选型方法、水系统设计要求以及水力测功器控制PID调节方法;讨论了转速转矩传感器的测量原理,给出了选型方法和安装使用要求;同时,还设计了基于PXI和LabVIEW的测控系统平台,经试验验证,设备运行良好,满足燃气轮机试验需求。     

Health Monitoring of Long-Haul Fiber Communication System Using Chaotic OTDR

A novel chaotic optical time-domain reflectometry(OTDR)-based approach was proposed for monitoring long-haul fiber communication systems with multiple fiber segments. The self-phase modulation and group velocity dispersion effects of the optical cable was considered in demonstrating the proof-of-concept experiment and simulation. In experiments, the correlation peaks are clearly obtained from the correlation trace between the reference and reflected(or scattered) light signals propagating in three optical-fiber segments. The technique affords a high spatial resolution of 2 m, and further long-haul fiber simulations indicate that the sensing distance can be more than 3300 km. Thus, the new proposed technique can be effectively applied for health monitoring of long-haul fiber communication systems.