旁压试验换算曲线法在工程勘察中应用

通过旁压试验与载荷试验实测资料对比 ,提出了旁压试验换算曲线法 ,用旁压试验替代载荷试验在某工程中运用 ,较准确查明了强风化层承载能力 ,充分论证了高层建筑物采用天然地基的可能性。     

Preparation and emission property of scandia pressed cathode

Scandia pressed cathodes were prepared by powder metallurgy method using mixed powder of scandia doped tungsten and barium-calcium aluminates obtained by different mixing methods.The element distribution uniformity greatly affected the emission property.The powder prepared by ball-milling had small particle size and uniform distribution of different elements.This kind of powder was favorable for the chemical reaction among Ba,Ca aluminates,scandia and tungsten to take place sufficiently to form active substance which can improve the emission property.The emission current density of the cathode prepared with ball-milling powder was about 8 times higher than that prepared by manually mixing method,4 times higher than Os coated M-type cathode.The higher content of the active substance on the cathode surface prepared by ball-milling led to the better emission performance of the cathode.     

氧化钪混合钨基扩散型阴极表面结构的研究

采用XRD、SEM和AES等分析方法对氧化钪混合钨基及浸渍后的阴极微观结构及表面活性元素的行为进行研究.结果表明:基体内Sc_2O_3弥散均匀分布.在阴极激活过程中,Ba和Sc从内部向表面扩散,在阴极表面形成含Ba、Sc、O的表面活性层,其厚度为M型阴极活性层厚度的10倍以上.对自由钪的产生机制进行了探讨.