Duan Fajie, Professor, Doctoral supervisor. Main research interests are laser and optical measurement, online testing, and underwater acoustic detection. In laser and optical measurement, he addresses new measurement challenges in industrial manufacturing through application of laser technology, optical testing, photoelectric sensor, computer vision detection and modern signal processing theory. He has explored new theories and methods with state-of-the-art technology and constructed advanced measuring equipment and systems for the sustainable development of the manufacturing industry. In online testing, he focuses on the running status parameters online measurement and compensation of major equipment including aircraft engines, gas turbines, machine tools, especially the high-speed rotary sheet online testing method based on tip timing parameters state principle. In underwater acoustic detection, he explores underwater acoustic detection of underwater towed array and fixed array implementations and technology based on array processing methods and techniques of underwater acoustic signals, etc.