On Nov.4, Prof. Walter Arnold from Fraunhofer-Institute for Non-Destructive Testing, Germany visited IACAS at the invitation of Academician Ying Chongfu.

Prof. Walter Arnold paid a visit to the Underwater Acoustic Transducer and Testing Technology Laboratory, the State Key Laboratory of Acoustics and the Ultrasonic Physics and Exploration Laboratory. Then he had a warm talk with Academician Ying Chongfu and many other friends there. Prof. Walter Arnold also gave a brilliant academic lecture titled "Ultrasonic modes in atomic force microscopy". He introduced cantilever vibration modes in atomic force microscopy (AFM), the spectrum and imaging of AFM and transverse AFM. After the lecture, the researchers of IACAS had a discussion with Prof. Walter Arnold on the researches of electromagnetic acoustic transducers of Rail Wheel.