Acoustics in Nanjing University


      Chinese were keen students at sound as remarked by Prof. Yuan-ren Zhao, a world known
linguist. Related phenomenon had brought to the attention for thousands of years although
the name of acoustics or the "study of sound" was firstly appeared by Shen Ke (1031-1095)
in his book Sketches and Notes by Menxi. In addition, the Theory of Sound by Lord Rayleigh
laid basis for my interest in this branch of science since I was an undergraduate of physi-
cs in mid 30's. This interest also encourages me to write the paper as entitled.

      Speaking of the history of development of acoustics at Nanjing University during my h-
omecoming from USA in summer 1951, I was a professor of physics offering courses for stude-
nts in nuclear physics and electromagnetism, but I didn't miss my favorite subject acoustics
for there were question raised by architects related to improving sound qualities from thea-
ters to auditoriums they designed. About two years later, a new problem came up from an army officer concerning the design of a long-range and high power loudspeaker for broadcasting sp-
eech signals etc. up to a distance around 10 km from the seashore. Together with my young as-
sociate W. Wu, we built up a small temporary anechoic chamber by testing some small sample speakers. The final design proved to be successful and won a nation-wide encouragement. The success also inspired us to do a further research on the effect of temperature and humidity
on the sound propagation by designing a one meter diameter hollow metal sphere with both sou-
nd source and receiver enclosed inside. This set-up proved to be capable of the measuring of sound absorption in various temperatures and humidity. This research won admirations from ac-
ousticians home and abroad.

      Up to spring of 1955, the laboratory was better equipped. The so-called the Acoustical Faculty was then formally established, with 6 faculty members plus some 20 junior and senior
year students majoring in acoustics. However it was considered to be the first acoustical gr-
oup among all Chinese universities or embryo of the Institute of Acoustics approved by the M-
inistry of Education of National Government later. In these years, students had some practi-
ce in audio-acoustics, including electro-acoustics, noise abatement by practicing outside the campus.

      International exchange began in late fifties by the mutual visits with then Soviet Un-
ion and Eastern Europe, exemplified by a joint research with Prof. E. G. Mihailov of Lening-
rad, which led us give a correct solution of a world debatable problem concerning the ultra-
sound absorption in ethyl acetate. The favorable comment by Prof. And Academician Brekhovsk-
ikh in 1956 w as quite an encouragement to students as well as young faculty members. Besid-
es researches d evoted to practical or applied problems, the lab also accepted the research
on "acoustics of solids" as assigned by the Ministry of Education shared with two other top universities strong in this field. But it was a pity that all preparations came to naught b-ecause of the "Cul-tural Revolution" in summer of 1966.

      Our research directions were somewhat readjusted because of a ten-year "close down" of
our teaching and researches. For keeping up the world progress, collaborations through acad-
emic exchanges with some famous acoustician of USA, UK, France, German and Italy took place
since these years. For example, the visit to Prof. R. Stephens of London University by Prof.
Y. Wang in early 1979, followed by my participating the 50th Anniversary of the Acoustical Society of America and became an invited professor of UCLA, which was followed by Prof. I. Rudnick's immediate revisit in the same year and he gave a series of lectures on low temper-
ature acoustics. Then the academic exchanges became more often, such as Prof. Y. A. Shui to Stanford, Prof. And Academician S. Y. Zhang to Wayne, Prof. X. F. Gong to Moscow etc. These exchanges became more often as years rolled on.

      What deserved special mention were the international acoustical conferences held in Na-njing since early eighties. For examples the workshop on Ultrasonics at 1985, attendees from abroad included Prof. B. A. Auld of Stanford, R. B. Thomson of Iowa, Prof. Thomas and Kuo fr-
om Wayne as well as other famous scientists from France. Another one with hundreds of partic-
ipants was a Sina-Japanese Conference held in 1987, both the 14th Int. Conference as well as
the 9th Int. Conference of Opto-acoustics were held in June 1996, plus the latest one worksh-
op on similar topics in year 2,000 at Hotel Hilton.

      Up to date of this writing, there is comparatively a big growth of the institute both t-
he number of faculty members from instructors to professors with about 16 full professors, gr-
aduate students up to 70 and around 160 undergraduate seniors. However, there are some 18 res-
earch programs going on, from nonlinear fluid dynamics, sonoluminescence, opto-acoustics, cha-
os communication to some more practical problems such as noise control and electro-acoustics. Some of these researches did win yearly national awards, I just mention one of the year 1999, also some equal amount of items won awards from the National Science Committee to other minis-
tries etc. As to myself, two problems have been considered to be chief contribution:
(1) The propagation of sound in foggy atmosphere and (2) The study of water tank soliton and
its unification and chaos. However, these two aspects have been continued some of my students
and made further progress. One more important progress needs special mention is the growth of
the younger generation of the institute. Although some of the senior colleagues were retired,
the institute remains to be more active by those of the young generation. The chair of the De-
partment of Electronics X. L. Wang and the Institute director J. C. Cheng with W. C. Chen are
all very capable administrators and prolific authors. So there will be a new realm in acousti-
cs beyond so far my already reported.

---- By R.J.Wei