If xm -a(modn) have solutions, then the number of its solutions is not relative to a, hence the formula of the number of solutions of the comgruence x"=l(modn) is the formula of the number of solutinos of the comgruence xm≡a(modn) ,too.

This paper introduces a new analytical formula for designing a planar rank and rocker mechanism according to travel velocity-ratio coefficient.

This paper introduces a new analytical formula for designing a planar rank and rocker mecha- nism according to travel velocity - ratio coefficient.

Based on the concept of equivalent soil resistivity and the previously derived analytic formula for grounding resistance of a single rod in two~layer soil, an analytic formula is deduced to estimate grounding resistance of combined grounding rods in two~layer soil.

Based on these properties we propose an analytic formula to reconstruct wave fields.

Based on Furior series,an analytic formula for analyzing the prestress in the web of box girder with single bar was deduced through simplifying the action of single vertical prestressing bar as a couple of concentrated forces with equal value but opposite direction acting on a thin rectangular board with infinite length.