用稀土多元渗法制备钾稀土钨青铜KxLayWO3的XPS研究

Potassium tungsten bronze K_xLa_yWO₃ (x>0.5 and y<0.01) was synthesized by rare earth co-permeation method using α-K₇[SiMg₃(OH₂)₃W₉O₃₇] as the precursor. Binding energies of La, W, O and C were determined by XPS. From the XPS data, a peak at 34.21 eV indicates that some W⁶⁺ turned into W⁵⁺ by rare earth co-permeation. The binding energies La3d were the same in the surface and inner of the composite, showing that rare earth element La could diffuse into the body of the composite and the compound of K_xLa_yWO₃ was formed at the same time. The binding energies of O1s in K_xLa_yWO₃ surface were 531.4 eV and 532.0 eV, respectively, while peak at 531.4 eV disappeared through etching process. The result implies that the binding energy of 531.4 eV was due to the adsorbent O. In addition, the binding energies of C1s in the surface were 283.5 eV, 285.0 eV and 286.7 eV respectively, while the inner had only one peak at 285.0 eV due to standard C1s. This proves that there was no C in the core.     

凸轮与平底从动件的接触变形与接触刚度计算

将凸轮与平底从动件接触视为二维线性接触,基于无限大半空间模型对从动件的变形量进行了分析,利用圆柱体二维线接触变形的计算方法对凸轮接触变形进行了计算,从而得到了凸轮与平底从动件的接触变形量与接触刚度理论计算公式。利用Palmgren公式和有限元方法对计算公式进行了验证,并分析了接触刚度与凸轮曲率半径、接触力之间的关系,结果表明:接触应力、接触半宽、凸轮接触变形量的理论计算值与有限元计算结果几乎相等,凸轮与从动件的接触变形量之和的理论计算值与有限元计算值相差小于5%;凸轮与平底从动件的接触变形之和、接触刚度都与接触处凸轮的曲率半径无关,而与凸轮与平底从动件间的接触力大小有关。