On the afternoon of June 30, 2021, at the invitation of the School of Electrical and Automation Engineering of Nanjing Normal University, Associate Professor Xuejun Yan and Associate Researcher Xin Li from the School of Modern Engineering and Applied Science of Nanjing University visited our school for academic exchanges and made a presentation in the meeting room 202 of Qiming Building. The academic report titled "Photoacoustic Nondestructive Testing Technology and Application" and "Mechanics/Acoustic Metamaterial Design and Performance". This report was hosted by Dr.Zhen Wang. More than 20 teachers, graduate students and undergraduates from our school participated in this academic exchange meeting.

Xuejun Yan, holds a doctorate degree in engineering. He is currently an associate professor at the School of Modern Engineering and Applied Science of Nanjing University, and the R&D director of the Institute of Photoacoustic Superstructure, Nanjing University. The main research directions are: photoacoustic interaction of artificial microstructures, ultra-fast "photo-acoustic-thermal" comprehensive experimental characterization technology, laser vibration measurement and laser ultrasonic non-destructive testing, low-dimensional nanomaterial heat transport research and micro-nano processing Technology etc. He has long been engaged in the research and development of acoustics, photoacoustics and ultrasonic testing instruments, and independently developed a series of high-precision acoustic and vibration measurement instruments such as laser ultrasonic high-speed imaging instruments, laser Doppler vibrometers, vector acoustic sensors, and acoustic cameras. More than 30 invention patents have been applied for, of which 13 have been authorized and 1 patent achievement has been transferred. Based on this type of testing equipment, he has published more than 20 high-level SCI papers such as Nat. Mater., Adv. Mater., APL, etc., presided over 1 National Natural Science Foundation Youth Project, participated in 1 National Major Instrument Research and Development Project, and Natural Foundation Key Project 1 item, undertook multiple enterprise technology research and development projects.

In the report, Mr.Xuejun Yan  first introduced the application prospects of laser ultrasonic technology in nondestructive testing fields such as industry and medicine, and pointed out that the application of laser ultrasonic nondestructive testing technology to the inspection of 3D printing molten pool can greatly improve the detection accuracy and detection efficiency. Then, Mr. Xin Li  enumerated the design and application of 3D printing technology (metal and non-metal) in mechanical metamaterials. At the same time, the significant effects of gradient mechanics metamaterials in central air conditioning and high-speed rail noise reduction are explained. Teachers Yan and Li elaborated on the broad application prospects of 3D printing in future industrial development and scientific research from the perspective of 3D printing non-destructive testing and 3D printing metamaterials.

After the report, the teachers and classmates discussed with Teachers Yan and Li, and exchanged scientific issues such as the impact of the measurement environment on the real-time detection of the 3D printing molten pool, and the application of 3D printing metamaterials to the noise reduction of high-speed railways. There is a strong academic atmosphere on site, and all teachers and students have benefited a lot. The academic report was successfully concluded with the warm applause of teachers and students. (Contributed by Wang Zhen)

                                                                June 30, 2021