珠算式的连身加法

连身加的前身叫定身加，若身外有数，叫身外加，这种算法早在唐代就已经产生(这种算法必须是法首为1)。到了宋代，杨辉将这种算法推广到法首不是1的情况(主要指法首是2)，命名为连身加。连身加的运算原理实质上与定身加一样，只不过是定身加几次而已。无论是唐代还是宋代有关论述这种算法的，讲的都是筹算、笔算。     

Shear Strength Measurements in LY-12 Aluminium Alloy During Shock Loading

Lateral stress of LY-12 aluminium alloy under plate impact shock loading was measured. Based on the measured data, the Hugoniot relation and shear strength were obtained. The result has demonstrated that the shear strength of the tested material increases remarkably with the increasing longitudinal stress. This means that the assumption of constant shear strength usually adopted in shock stress calculation is not suitable for the present material.