L. E. El’sgol’ts, “Differential Equations,” in the Series International Monographs on Advanced Mathematics and Physics, Gordon and Breach Publishers, Inc., New York, and Hindustan Publishing Corporation, Delhi, 1961, pp. 145-155.

has been cited by the following article:

• TITLE: A New Differential Operator Method to Study the Mechanical Vibration

  AUTHORS: Quansheng Ji, Xiaomei Ji, Linhong Ji, Yuxi Zheng

  KEYWORDS: New Differential Operator Method; Mechanical Vibration (Torsional Vibration of Rolling-Mill); Torque Amplification Factor; Model Analysis Method; Laplace Transform

  JOURNAL NAME: Modern Mechanical Engineering, Vol.2 No.3, August 31, 2012

  ABSTRACT: In this paper, we propose a unified differential operator method to study mechanical vibrations, solving inhomogeneous linear ordinary differential equations with constant coefficients. The main advantage of this new method is that the differential operator D in the numerator of the fraction has no effect on input functions (i.e., the derivative operation is removed) because we take the fraction as a whole part in the partial fraction expansion. The method in various variants is widely implemented in related fields in mechanics and engineering. We also point out that the same mistakes in the differential operator method are found in the related references [1-4].