We refer you to the prefix circular of our mr. t. r. announcing the establishment of our firm In this city .

请参照我们公司 T.R.先生的 介绍 函，该函通知本公司将于本市开业。

First order nonlinear non - holonomic mechanical systems having variable mass was deduced from the T. R. Kane 's equation for the mechanical systems having variable mass .

本文从变质量力学系统的 Kane方程，推出了变质量一阶非线性非完整系统的拉格朗日方程。