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
Meanwhile, we put forward symmetric correction to resolve inherent error cumulation of point-by-point imaging modality.
同时进一步提出对称校正的方法以解决逐点成像法固有的误差累积。
3
In this paper, we show that the Pseudo-Symmetric property of spherical point set can be characterized by the eigen values of eigenpolynomial and it has the closeness under the metric sum operation.