Calendar: 1974-1975 Page 439

Iviii Annual Report of the Delegacy The application of novel transducers and nonlinear acoustic wave interactions to flow measurements and inspection methods is one of the principal objectives of the ultrasonics research guided by Professor Turner During the year detailed calculations of non-linear behaviour in piezoelectric semiconductors have been completed and will be applied to the design of real-time acoustic convolution and correlation devices Professor Turner visited the University of Toronto McGill Uni- versity and the Bell Telephone Laboratories at Murray Hill and Holmdel New Jersey during the summer to discuss acoustic wave and optical communications research He also visited the Headquarters in New York and the Ecole Superieure d'Electronique et de Radioelectricite Bordeaux University The first objective of Dr Lindsay's work on noise in collision free systems has been achieved by expressing the problem in terms of fairly general class of random fractions The applications of the method to systems comprising crossed electric and magnetic fields is now being investigated The work of his group on mode-locking in lasers is continuing with the interest gradually concentrating on the transient behaviour and noise properties of such systems Dr Burtt completed major portion of his research on low energy bombardment of clean metallic surfaces in ultra high vacuum by publishing the results of his investigations Mr Boff continued his research on the effects of thermal and flicker noise on the spectral output of electronic oscillators He was invited to give lecture to the engineering and research staff of Racal Electronics Ltd on 'Level control mechanisms in electronic oscillators' As part of the programme of intercollegiate co-operation he gave series of lec- tures at University College Department of Electrical and Electronic Engineering on 'Profit or Loss-an Introduction to Break-even Analysis' The Department entertained many distinguished visitors during the session Among these Professor Polak from Berkeley gave talk on optimisation techniques Professor Wessel Berg from the Norwegian Technical University Trondheim discussed travelling wave amplification in semiconductors and Mr Willshaw for- merly Director of Research company lectured on the elec- tronic valve industry Mr Alan Reddish of was reappointed Visiting Professor for second year and gave two lectures on technical communication to the Department