Sigma as being cylindrically symmetric about the bond axis, and it's important to point out that it has no nodal plane across this bond axis.
键是，So, we, talk, about, a, sigma, bond，关于键轴圆柱对称的，需要着重指出的是，而且沿着键轴是没有节面的。
2
The problem of an elastic plane having symmetric parabolic crack is discussed.
研究含轴对称抛物线曲裂纹平面弹性问题。
3
The symmetric values about the imaginary axis of zero-poles which the unstable process lies in the open and closed right-half plane are defined as their mirror-injection.