发达国家高校与企业科研合作的经验

随着科学技术和社会经济的发展,高等学校和社会的关系日益密切。高等理工科学校要培养出适应工业企业需要的高质量人才,必须克服脱离社会、脱离实际的倾向。为此,高校正在积极探索与社会,特别是与工业企业进行科研合作,培养高质量人才的新路子。本文仅就发达国家高等学校与企业在科研合作方面所取得的成功经验作概要介绍。     

白泥比表面与活性对铝酸钠溶液脱硅的影响

在以前的一些著作中,我们曾经指出,铝酸钠溶液在有大量白泥存在时,不论在压煮器里,还是在敞口的搅拌槽中脱硅都能获得高纯度的溶液。例如,当接近于工业成分的铝酸纳溶液,在无添加剂或有100克/升白泥的条件下,在压煮器里于170℃下进行脱硅时,所     

液化石油气钢瓶环缝锁底接头两道埋弧焊工艺

介绍了液化石油气钢瓶环缝锁底接头、两道埋弧焊工艺。锁底接头成形加工工艺简单，上下封头组对操作便利。环缝焊接质量稳定可靠，生产率高，适用于大规模机械化生产，是一种能使钢瓶生产实现优质高效的焊接方法。     

美国人对纳米技术态度分歧

在金属切削行业，有关纳米技术刀具涂层的各种报告非常令人鼓舞：纳米涂层能提高刀具的断裂韧性，并使刀具能加工出光洁度更高的工件表面；纳米涂层使机床能以更高速度进行加工，并可在干式或准干式切削条件下进行加工。     

缝隙式浇注系统在ZCuAl9Fe4Ni4Mn2轴套上的应用

YB25.01.057-42轴套是8000型烟机关键件之一,材料为ZCuA19Fe4Ni4Mn2,铸件重10 kg.技术要求为φ94 mm(毛坯φ100 mm)表面粗造度Ra0.40 μm,不许有气孔、渣孔,否则镀不上铬.原工艺采用传统的底注式浇注系统,废品率达50%以上.经分析,改用缝隙式浇注系统,废品率降至8%以下,大大加快了生产进度,降低了生产成本.     

高速动车组转臂定位座焊接质量控制

针对动车组转向架转臂定位座焊缝出现焊缝未熔合、焊缝咬边、焊接变形难控制及生产效率低等问题,通过分析转臂定位座的结构特点,优化了焊接工艺参数及焊接顺序。结果表明,优化后的焊接工艺有效解决了焊缝质量问题,焊后无需进行返修、调修。该方法节省了大量的劳动成本和生产成本,显著提高了生产效率。     

Fabrication of niobium doped Pb（Zr, Ti）O3 fibers by viscous polymer processing

A technique based on viscous polymer processing （VPP） was described, which can produce high ceramic content green fibers. PZT-5 ceramic powders were ball milled to get high dispersibility. The slurry prepared for VPP was a composition of PZT-5 powder, PVA binder and glycerin. High ceramic content PZT-5 fibers were extruded with the slurry. The results show that the ceramic powders have fine mean particle size of 0.54 pan, high specific surface area of 3.55 m^2/g and zeta potential of 8.81 mV after 16 h milling. The fibers sintered at 1 280 ℃ for 4 h have pure perovskite structure and grains of 2-5 μm in size, with little pores or cracks. The ultimate tensile strength of sintered fibers is up to 13.84 MPa compared with 2.88 MPa of green fibers. The remnant polarization （Pr） and coercive field （Ec） of the fibers are 50.65 μC/cm^2 and 2.45 kV/mm, respectively. This fiber can withstand an electric field of 9 kV/mm higher than the ceramic （5 kV/mm）, which shows high directional and compact qualities.     

Effect of Zr content on quench sensitivity of AlZnMgCu alloys

The effect of Zr content on quench sensitivity of AlZnMgCu alloys was investigated by mechanical properties testing and microstructure observations. The results show that with the increase of Zr the quench sensitivity relative to hardness and strength increases, while that relative to elongation decreases. From hardness and strength viewpoints, the low quench sensitivity is observed for the Zr-free and 0.05% Zr-containing alloys, which is quite quench sensitive from the ductility viewpoint. The largest quench sensitivity relative to hardness and strength is observed for 0.1% Zr-containing alloy, this is mainly due to large amount of high angle grain boundaries and incoherent Al3Zr dispersoids caused by recrystallization, which may efficiently promote heterogeneous precipitation during air quenching. More than 0.05% Zr can significantly decrease the quench sensitivity relative to ductility, which can be primarily attributed to recrystallization inhibiting and grain refining effects of Zr.     

电化学清砂

我厂铸造车间生产的液压元件毛坯,材质是高强度孕育铸铁,要求铁水浇注温度较高,造型方法采用湿型,铸件表面粘砂严重。又由于内腔结构复杂,芯砂很难完全清除,仅采用普通的清理方法,往往得不到满意的效果。一九七二年我们参考日本进口燃气加热式电化学清砂设备,自制安装了一套硅整流、电阻加热式电化学清砂系统,几年来的生产实践证明     

全桥式逆变电路抗单向偏磁自动调节保护电路

本文提出了全桥式逆变电路抗单向偏磁自动调节保护电路。该电路通过提取变压器承受的双向电压信号和工作磁通信号以及实时进行闭环反馈控制,保证了全桥式逆变焊接电源的变压器正反向工作磁通相等,从而解决了全桥电路的不平衡问题。