Abstract: A fault detection method for a rotating machine based on sparse time synchronous averaging is disclosed, and the method includes: collecting a vibration signal and a rotating frequency or rotating frequency pulse signal of the rotating machine and performing analog-to-digital conversion to obtain the vibration signal and rotating speed information by a sensor; according to the type and number of detection components in the rotating machine, constructing a component-aware comb vector g based on the vibration signal and rotating speed information, wherein the type includes the gear, rotor and bearing; constructing a quasi-time synchronous average vector w based on the component-aware comb vector g; constructing a sparse time synchronous averaging model F by using the quasi-time synchronous average vector w; solving the sparse time synchronous averaging model F with an optimization solution algorithm to obtain a sparse spectrum and a reconstruction time signal.

Abstract: Disclosed is a method for determining 224Ra in a sediment by using a pulse ionization chamber emanometer, which belongs to the technical field of analysis and measurement. A pulse ionization chamber emanometer (PIC), a new emanometer, is used. Based on the half-life characteristics of different radon isotopes, one can separate the 220Rn activity from the total counts by dual counting. The resulting 220Rn measurement then can be used to determine the 224Ra activity in sediment according to the principle of secular radioactive equilibrium.