A Cu-Sn-Pb alloy modelled after an antique was cast and the powder-corrosion (P-C) was prepared on it under simulated na......

本文介绍了坐标面的垂直面上圆的轴测投影的一种比较简便的画法。一般平面上圆的轴测投影是椭圆,本文通过理论推导计算作出了一种......