a calculation formula的用法和样例：
- Based on the morphological characteristics of riverbed of tidal estuaries, a calculation formula for the widening rate of the estuarine regulation line is derived.
- Based on the coupling relationship among effective thrust, rotation speed, penetration rate and drillability index, a calculation formula is established.
- This paper also presented a calculation formula for computing the upper limit of total sum that the singular positions may probably be engenderd in arbitrary complicted multiloop planar mechanism.
- In this paper, a calculation formula of a spiral antenna with input impedance is deduced, then the geometrical size of a spiral antenna is optimized based on the related technical standard.
- According to the characteristics of double wall corrugated filter well pipe and its failure,a calculation formula of its critical confining pressure was induced by using elastic stability theory.