On November 19th, Professor Guo Jianzhong from Shaanxi Normal University visited the laboratory and gave a wonderful lecture entitled "Ultrasonic Evaluation and Rehabilitation Research of Skeletal Muscle Fatigue". Professor Guo started the discussion from theoretical research and discussed the work content of the other laboratory for many years. The work content not only includes the research of algorithms and the construction of experiments, but also the research and development of instruments and the cooperation of industry, university and research. The scope of the content and the scope of coverage left a deep impression on the audience. After the meeting, Professor Guo also invited colleagues from the laboratory to Xi'an for exchanges and inspections, and to further expand the communication and cooperation between the two laboratories.