Effect of surface modification of metal hydride electrode on performance of MH/Ni batteries

A novel method was applied to the surface modification of the metal hydride(MH)electrode of MH/Ni batteries.Both sides of the electrode were plated with a thin silver film about 0.1μm thick using vacuum evaporation plating technology,and the effect of the electrode on the performance of MH/Ni batteries was examined.It is found that the surface modification can enhance the electrode conductivity and decrease the battery ohimic resistance.After surface modification,the discharge capacity at 5C(7.5A)is increased by 212 mA.h and the discharge voltage is increased by 0.11 V,the resistance of the batteries is also decreased by 32%.The batteries with modified electrode exhibit satisfactory durability.The remaining capacity of the modified batteries is 89%of the initial capacity even after 500 cycles.The inner pressure of the batteries during overcharging is lowered and the charging efficiency of the batteries is improved.     

基于虚拟仪器的频谱分析仪设计

运用LabVIEW软件，结合数据采集模块LabJack U12，实现频谱分析虚拟仪器的设计。本文主要介绍频谱分析虚拟仪器的功能及软件设计方法     

含缺陷海洋井架承载能力及剩余寿命分析北大核心

为掌握某在役海洋修井机井架的实际承载能力和剩余寿命情况,结合ANSYS APDL命令流和井架承载能力评估方法,建立井架承载能力可视化有限元模型;利用等效截面法建立含缺陷井架模型,分析腐蚀、杆件初弯曲、应力集中3种缺陷对井架承载能力的影响;通过加载应力测试结果对模型进行验证,并在此基础上提出基于年腐蚀率的井架剩余寿命预测方法。结果表明:采用无缺陷井架模型分析井架实际承载能力存在较大误差,不能准确反映井架的实际受力和变形情况;含缺陷井架模型分析结果同加载应力测试结果吻合,模型准确,3种缺陷中腐蚀缺陷对井架实际承载能力影响最大。经分析,该井架实际承载能力为865 kN,剩余寿命为13a,分析结果可为井架安全作业提供参考。     

TiAl/Ti/V/Cu/40Cr钢扩散连接界面组织结构对接头强度的影响

研究了TiAl/Ti/V/Cu/40Cr钢的扩散连接，结果显示：在TiAl/Ti界面处形成了对接头强度有利的Ti3Al TiAl双相层及Ti固溶体层，而Ti/V/Cu/40Cr界面处未出现金属间化合物及其它脆性相，接头最高拉伸强度可达420MPa，接近TiAl母材。     

熔模铸造熔炼车间防止金属浪费的三点措施

分析了当前熔模铸造所面临的形势，指出了生产实践中熔炼车间容易造成金属浪费的三个环节，并提出了相应的预防措施。通过加强管理，避免浪费，降低了铸件生产成本，增强了市场竞争能力。     

面向焊接的软开关有源功率因数校正仿真研究

在分析软开关有源功率因数校正电路原理的基础上，建立了一套软开关有源功率因数校正的仿真电路。通过仿真，研究了在不同静态负载下实现全程软开关的条件。并研究了谐振电容和谐振电感的参数对整个电路性能的影响，对谐振电容和谐振电感的选取具有指导意义。     

Mechanical properties and microstructures of hot extruded AE42 alloy with addition of zinc

Mechanical properties and microstructures of AE42 magnesium alloy with addition of Zn and subjected to hot extrusion at 370 ℃ and an extrusion ratio of 8：1 were investigated. The results show that for the AE42 alloy, the addition of Zn can obviously improve its elongation as well as the ultimate tensile and yield strengths below 150 ℃. The addition of Zn can refine the mierostructure of the AE42 alloy, and result in the precipitation of Mg17Al12 and MgZn2 phases. Due to the addition of Zn to the AE42 alloy, the amount of Al11RE3 phase decreases, while the Al11RE3 phase becomes short rod-shaped from acicular and block, and distributes along the grain boundaries, which will have a stronger effect on the tensile properties of the alloy at elevated temperature. In addition, with the presence of MgZn2 precipitates, the sliding of grain boundaries is restrained and the strength of the alloy gets enhanced.     

聚酯反应器熔化极气体保护焊接

MAG焊因其高效受到焊接界的青睐，但因飞溅大和形差有其引起机械性能下降等原因，在压力容器焊接上一直受到限制。随着国内外MAG焊设备、工艺和焊接材料的技术进步，这一局面正在得到改观。介绍了聚酯反应器夹套封头／端盖焊接上采用MAG焊的一些情况，着重介绍了如何从焊接工艺、焊接设备、焊接材料方面解决飞溅和成形问题。     

自动轧管机组的计算机软件系统

介绍了自动轧管机组计算机软件系统的功能与结构、硬件与软件的配置。分析了穿孔轧制压力的数学模型。     

贵金属深加工的废水处理方案

金银等贵金属实现其工业用途的前提是对其进行深加工，在深加工过程中产生的大量含酸、碱、重金属和氰化物的废水对环境造成的危害已经成为社会极为关注的问题。本文对这类废水的来源和常用处理方法进行了论述，提出一套适合于以金银作为深加工对象的废水处理方案，在保证充分回收贵金属的前提下，合理地使废水中的氰化物、重金属、酸和碱得到有效的处理。本文案具有经济、简便和实用的特点。