Table 1.

Three coefficients of the modal function.

Mode	${\mathit{\sigma }}_{\mathit{i}}$	${\mathit{\beta }}_{\mathit{i}}$	${\mathit{\gamma }}_{\mathit{i}}$
1st mode	0.3669	1.8746	−1.3629
2nd mode	−0.5093	4.6927	−0.9818
3rd mode	0.4996	7.8500	−1.0080