On Apr. 24, 2007, Dr. Lan Jun was invited to give a report in our institute. The report was on Transducer and Calculation Method of Array Numerical Value. In his report, Dr. Lan introduced Finite-element Design Transducer, Array Calculation Analysis and some other hot issues in this field. The seminar was anchored by Research Professor Mo Xiping. After the report, Dr. Lan had a warm discussion with the audience.