一种改进的超薄聚丙烯酰胺等电聚焦电泳实验

目的:介绍一种自制、简易、高效的平板微型聚丙烯酰胺凝胶等电聚焦电泳方法。方法:将载玻片黏合作为制胶模具,剪滤纸制成上样芯子进行等电聚焦电泳。结果:电泳条带清楚,样品容量大,电泳时间短,操作性强。结论:此方法简单、有效、实用,所需凝胶量少,节约成本,值得推广。

The comparison between laser screw welding and resistant spot welding of lap joint with large thickness ratio

The present paper investigates the welding forming,microstructure and shear tensile test of lap joints with large thickness ratio which were fabricated by laser screw welding(LSW)and resistant spot welding(RSW).The comparison was conducted on two kinds of lap joints,galvanized sheet and hot pressed steel(GS-HPS),galvanized sheet and high strength steel(GS-HS).The microstructure and fracture morphology were analyzed by optical microscope.It was demonstrated that with large thickness ratio the sound lap joint of GS-HS could be obtained by LSW regardless of the irradiation of laser beam from thick metal to sheet or otherwise,and the morphology shows it is better when the laser is irradiated on the thick metal.Nevertheless,when the laser beam was applied on thick metal of HPS,blind hole or blowhole was formed in the center of joint,which is attributed to the shrinkage during solidification of the molten pool.Small pores or dispersed porosity appeared on the faying face of the joint without predetermined gap which provides the degassing.However,the increase of predetermined gap could reduce the shear strength and nugget size.Two kinds of joints made by LSW have superior shear strength than those made by RSW when the laser were applied on galvanized sheet.

Microstructure, Mechanical Property and Corrosion Resistance Property of Cr26Mo3.5 Super Ferritic Stainless Joints by P-TIG and Laser Welding

The characteristics of microstructure, mechanical property and corrosion behavior of Cr26Mo3.5 super stainless steel joints by pulse tungsten inert gas(P-TIG)welding and laser welding were investigated. The results indicate that the widths of the center equiaxed grain zone(EGZ)and the columnar grain zone(CGZ)increase with the increase of heat input in both welding processes. The precipitates of Nb and Ti carbides and nitrides are formed in the weld metal(WM)and the heat affected zone(HAZ). The joints by laser welding show better tensile and corrosion resistance properties than those by P-TIG welding due to the heat concentration and lower heat input. The tensile strength and elongation increase with the decrease of heat input, and the fracture mode of the joints turns into ductile-brittle mixed fracture from ductile fracture when the welding method turns into P-TIG welding from laser welding. Moreover, the corrosion resistance of all joints declines slightly with the increase of heat input. Hence, laser welding is more suitable for welding Cr26Mo3.5 super stainless steel in engineering applications.

激光螺旋点焊在白车身焊装上的应用分析

用激光螺旋点焊针对两层镀锌薄板工况进行焊接,结果表明合适的焊接参数和预留板间间隙条件下,焊缝成形良好,焊缝组织在搅动作用下得到细化,接头的力学性能优于常规电阻点焊。增加板间间隙使得焊核尺寸减小,接头力学性能降低,但仍和电阻点焊相当。经过分析,激光螺旋点焊可代替电阻点焊和弧焊,提高生产效率和作业可达性,提高车身结构设计自由度,在白车身焊装工艺中具有较大的应用潜力。

旅团部队应先行建立办公用品集中采购制度

一、旅团部队推行办公用品集中采购的必要性1.旅团部队推行办公用品集中采购是军队预算改革的配套之举。新的预算改革要求,上年度要对下年度的经费进行全面测算,各项经费和物资都必须全部纳入预算。

变电检修过程中的设备维护与保养策略研究

本文旨在研究变电检修过程中的设备维护与保养策略。变电站作为电力系统中的重要组成部分,其设备的维护与保养对电力系统的安全运行至关重要。通过制定科学合理的维护与保养策略,可以延长设备的使用寿命,提高设备的可靠性,降低故障风险。本文综述了相关文献和实践经验,总结了变电检修过程中的设备维护与保养策略的研究现状和应用效果,为变电站设备的维护与保养提供理论和实践支持。

变电设备振动监测与故障诊断技术研究

本文研究变电设备振动监测与故障诊断技术,旨在实现对设备运行状态的实时监测和故障诊断。研究介绍了变电设备振动监测的重要性,讨论了变电设备故障诊断技术的应用。详细介绍了基于振动信号的故障诊断方法,最后分析了变电设备振动监测与故障诊断技术面临的挑战。通过本文的研究,可以提高变电设备的可靠性和安全性,为电力系统的稳定运行做出贡献。

成都地铁一号线车辆紧急通风逆变器故障检测方法研究

基于紧急通风逆变器工作原理,研制了紧急通风逆变器故障检测设备,并对检测设备的正确性进行了验证。目前该检测设备已应用于地铁车辆检修工作中,有效避免了紧急通风逆变器故障件上车和故障返修件入库,大大节省了紧急通风逆变器的检修时间。