I. D. Avramov is with the Institute of Solid State Physics, 1784 Soï¬a. Bulgaria. F. L. Walls and T. E. Parker are with the National Institute of Standards ...... Ultrasonics and the Frequency Control Symposia, and was the Technical. Program Chair for the ... in Orlando, and the 1992 IEEE Ultrasonics Symposium in Tucson. He is.
