# Wang Dezhao

Wang Dezhao or Ouang Te-Tchao (Chinese: 汪德昭; December 20, 1905 – December 28, 1998) was a Chinese physicist who was known for his research in atmospheric electricity and underwater acoustics. Under the direction of Paul Langevin, he helped the French improve sonar at the beginning of World War II and after his return to China, Wang was considered as the founder of national defense water acoustics in China.

## Early life and education

Wang was born in 1905 in Guanyun, Jiangsu, China to an intellectual family. His father was a graduate of Liangjiang Higher Normal School in Nanjing and later served as a civil servant at the Ministry of Agriculture and Forest of the Republic of China. Wang grew up in Beijing. In 1928, one year before his graduation from the Physics Department of Peking Normal University, he was appointed T.A. by his professor, university president Zhang Yihui who then by the end of 1931, introduced Wang to the prominent French physicist Paul Langevin during his visit to China. This encounter pushed Wang's decision to pursue his studies in France. In 1933, he made the trip to Europe. After one year as a language student at the Université Libre of Bruxelles, he became Langevin's student at École supérieure de physique et de chimie (ESPCI) of Paris where Langevin was the head.

## Career in France

Wang was entrusted by Langevin with the research on ionization of particles suspended in the atmosphere, a domain in which Langevin himself had abundantly researched at the turn of the 20th Century for his own doctoral thesis, and in which the world of scientists were increasingly interested for its utility in meteorology and radio-electronics. From 1934 to 1940, Wang published 9 scientific papers and completed the task with his French state doctoral thesis on the Electrization of the Particles Suspended in the gas. Langevin performed a complementary calculation on the results obtained by Wang on a roll of toilet paper when he was secretly imprisoned during 38 days by the Gestapo and then, he reviewed a part of Wang's thesis when he was under house arrest by the end of 1940. Wang's new discoveries on the equilibrium between big and small ions of suspended particles in the gases, as well as the equation he obtained between the numbers of big/small ions and the mobility of small ions, confirmed and completed later by another French scientist J. Bricard in 1948, was referred to as "Langevin-Ouang-Bricard" theory by the geophysical science community in the 1950s.
In 1939, shortly after France and U.K. declared war against Nazi Germany, while all the Langevin laboratories at ESPCI was converted to the Research Group IV of the National Defense Ministry, Wang worked on multiplying the emission power of the ultrasonics submarine detector - known as Sonar today - that Langevin invented by the end of World War I using piezoelectric quartz crystals transducer. Wang succeeded to increase its power per unit area by applying sintering process, which improved greatly the efficiency and the reliability of the active sonar system. The technology was transferred to the UK Royal Navy for immediate implementation. Wang has also succeeded to put together an acoustic system capable of dispersing the heavy fog on military airports by creating large amplitude sound waves using a series of high air pressure Hartmann whistles causing the dispersal of particles suspended in the air.
A profound friendship was built up between Ouang and Langevin beyond their student-teacher relationship. During the World War II, while Langevin was under home arrest, Wang refused to work for ESPCI led by a pro-German director Jean Thibaud and joined Irène and Frédéric Joliot-Curie - also student of Paul Langevin - at their Institute du Radium, where he researched more in radioactivity until the liberation of Paris by allied forces and the return of Langevin to ESPCI. From that point to the middle of 1950s, while continuing the research in ionized gases based on Langevin's theory and his previous work, Wang made breakthroughs in the following domains:
* Inventing high sensibility electrometers;
* Measuring the absorption, dispersion and speed of ultrasound in fluid;
* Proving the existence of negative electrophoresis discovered by Felix Ehrenhaft;
* Using β ray to measure and control the thickness of emulsion on photo film and paper.
After the war, Wang was awarded with the Prix Hughes by the Academie des Sciences in 1945 for his contribution in the field of ionized gases; and was promoted by Centre national de la recherche scientifique (CNRS) from researcher to research director. In 1947, by the recommendation of Frédéric Joliot-Curie, he was appointed consultant to the Commisariat à l'Energie Atomique (CEA). He has also been working as scientific consultant for some private companies in France and in the U.K., la Société Quartz and Silice among others.
Influenced by Langevin and Joliot-Curie, both French communist party members, as well as the communist dominant French Resistance movement during the german occupation of the WWII, Wang was also involved in the social life in Paris. In 1949 he was elected president of Association of Chinese students in France - a progressive association regrouping the left-wing Chinese students - disbanded in the fall 1952 by the French government under the global anti-communist waves and at the request of the Republic of China's government withdrawn to Taiwan in the late 1940s.

## Career in China

With his sympathy for the communist movement in China, Wang moved back to People's Republic of China in 1956, seven years after the communists took control and seven years before France formally recognized it. Wang's return to China, as the return of many other western-educated scientists at the same period, was highly anticipated and celebrated by the highest level communist leaders, they saw on him the key to build up a crucial part of the young regime's national defense system - sonar - dubbed as "the underwater great wall". Wang entered the Chinese Academy of Sciences (CAS), where he was elected as academician in 1957, served as associate director of Institute of Electronics in charge of the underwater acoustics research. In 1964, he helped set up the Institute of Acoustics (IOA) and served as its director. Approved by the Chairman Mao Zedong and Premier Zhou Enlai, 100 undergraduate students were picked by CAS even before their graduation from three most prestigious colleges of the time - Peking University, Tsinghua University and Che Kiang University - to form Wang Dezhao's research team. Wang wrote textbooks, trained the young team personally and set the stage for their research career, while leading the experiments on and under the South China Sea.
Wang survived the Culture Revolution (1966-1976) during which the IOA was dismantled, while himself was deprived of all positions and subjected to humiliations, confiscation of property, tortures, custody. After Deng Xiaoping seized power in the aftermath of Mao's era in 1977, Wang wrote a long letter urging Deng to put the IOA and his team back on track. He obtained an immediate favorable response.
Through his retirement in 1984, Wang supported his students to succeed in various basic research subjects, among others:
* on the normal mode theory;
* on the theory of horizontal coherence of signal field in shallow water;
* on the relationship between sound field and bottom-reflection-loss in shallow water;
* on the theory of turning-point convergence-zones in deep underwater sound channels in the South China Sea;
* on the effects of internal waves on the underwater sound propagation.
In addition, a series of advanced defense and civil sonar products were also developed. One of the most important was the Bottom-Fixed Underwater Acoustic Surveillance System designed, developed and manufactured by Wang and his students.
Along with scientific papers, Wang has authored with his students English-Chinese, French-Chinese scientific lexicons of acoustical terms and, in 1981, a treatise entitled Underwater Acoustics.
Wang served several terms as representative in China's National People's Congress and as member in standing committee of Chinese People's Political Consultative Conference. In the 1980s, he re-established the Association of Old Students from France and served as Chairman for one term; he also petitioned to create the Middle School affiliated to the Chinese Academy of Sciences, known as Zhongguancun Middle School today, and served as honorific head of school.

## Awards

France
* 1945 : Prix Hughes awarded by Académie des Sciences for his research in ionized gases
* 1980 : Médaille étrangère by French Acoustical Society
* 1992 : Officier de la Légion d'honneur awarded by François Mitterrand - Président de la République, decorated by Hubert Curien - Minister of Research
China
* 1982, 1989 : National Natural Science Award
* 1982 : Prize for Important Scientific and Technological Achievements
* 1997 : Ho Leung Ho Lee Prize in Physics

## Publications and references

* 1 2 3 "CAS Members----Institute Of Acoustics Chinese Academy Of Sciences". english.ioa.cas.cn. Retrieved 2019-01-15.
* ↑ 陈恂清 (1995). 汪德昭院士传略. 北京: 海洋出版社. ISBN 7-5027-3814-2.
* ↑ Note de M. Ouang Te-Tchao, Présentée par M. Paul Langevin (1936-11-03). "Sur la numération des particules en suspension dans l'air". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 203: 855 – via Gallica.
* ↑ Note de M. Ouang Te Tchao, Présentée par M. Paul Langevin (1937-03-15). "Sur la grosseur des particules de fumée mises en suspension dans l'air". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 204: 852 – via Gallica.
* ↑ Note de MM. Ouang Te Tchao et André Langevin, Présentée par M. Paul Langevin (1937-11-29). "Sur l'état d'équilibre entre gros ions est petits ions dans un gaz". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 205: 1049 – via Gallica.
* ↑ Note de M. Ouang Te-Tchao, Présentée par M. Paul Langevin (1938-01-10). "Sur le spectre de mobilités des gros ions". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 206: 240 – via Gallica.
* ↑ Note de M. Ouang Te Tchao et Mlle Anne-Marie Moulin, Présentée par M. Paul Langevin (1938-05-09). "sur l'état d'équilibre entre gros ions et ions produits par les rayons X dans un gaz". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 206: 1464 – via Gallica.
* ↑ Par MM. Henri Le Boiteux, Ouang Te-Tchao (1938-07-21). "Sur la loi de répartition des mobilités des gros ions". Journal de Phys et le Radium. 1938, 9 (11): 501–504 – via HAL.
* ↑ Note de M. Ouang Te-Tchao, Présentée par M. Paul Langevin (1939-01-23). "Sur la formation des gros ions dans les gaz en fonction de la grosseur des particules en suspension". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 208: 271 – via Gallica.
* ↑ Note par MM. Ouang Te-Tchao et Henri Le Boiteux, transmise par M. Paul Langevin (1939-04-24). "Sur le coefficient d'absorption des petits ions par les particules neutres en suspension dans l'air". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 209: 1288 – via Gallica.
* 1 2 Note de M. Ouang Te Tchao et Mme Odette Thellier, transmise par M. Paul Langevin (1940-12-30). "Sur l'équilibre ionique dans l'atmosphère". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 211: 799 – via Gallica.
* 1 2 Te-Tchao, Ouang (1941). "Recherches sur l'électrisation des particules en suspension dans les gaz au moyen des ions produits par les rayons X ou par des corps radioactifs". Annales de Physique (in French). 11 (16): 47–144. Bibcode:1941AnPh...11...47T. doi:10.1051/anphys/194111160047. ISSN 0003-4169.
* ↑ André Langevin (1971). Paul Langevin, mon père, l'homme et l'oeuvre. Paris, France: Les Editeurs Français Réunis. p. 174.
* ↑ Bricard, J. (1949-03-01). "L'Equilibre ionique de la basse atmosphere". Journal of Geophysical Research. 54 (1): 39–52. Bibcode:1949JGR....54...39B. doi:10.1029/JZ054i001p00039. ISSN 2156-2202.
* ↑ Bruno Vitale, Annali di Geofisica (June 1952). "Equilibrio Ionico Nella Bassa Atmosfera e le Teorie Sulla Ricombinazione".
* ↑ Holl, W.; Mühleisen, R. (1955-05-01). "On the equilibrium of ionisation in air containing nuclei". Geofisica Pura e Applicata. 31 (1): 115–118. Bibcode:1955GeoPA..31..115H. doi:10.1007/BF01999592. ISSN 1420-9136. S2CID 122649619.
* ↑ Mokrý, Pavel (2016-09-01). "100 years of piezoelectric materials in acoustics - From a sonar to active metasurfaces". Proceedings of Meetings on Acoustics: 045008. doi:10.1121/2.0000521. {{cite journal}}: Cite journal requires |journal= (help)
* ↑ "Paul Langevin". www.ob-ultrasound.net. Retrieved 2019-01-16.
* ↑ 科技日报 陈东 (1989-09-14). "奔向太阳升起的地方 记汪德昭院士".
* 1 2 3 4 5 Liu Zhenkun, Liu Tianming (2008). WANG Dezhao. Beijing, China: Gold Wall Press. ISBN 978-7-80251-038-8.
* ↑ Note de MM. Jean Surugue et Ouang Te-Tchao, transmise par M. Paul Langevin (1943-08-09). "Sur la diffraction des rayons X par le quartz en oscillation ultrasonore". Comptes rendus hebdomadaires des séances de l'Académie des sciences – via Gallica.
* ↑ Note de MM. Ouang Te-Tchao, Jean Surugue et Tsien San-Tsiang, Présentée par M. Frédéric Joliot-Curie (1943-11-08). "Intensité absolue des électrons de conversion de RaD". Comptes rendus hebdomadaires des séances de l'Académie des sciences – via Gallica.
* ↑ SURUGUE, Jean; OUANG, Te-Tchao (December 1943). "Influence des ultrasons sur la diffraction des rayons x par le quartz". Cahier de Physique. 18: 10 – via ESPCI Bibliothèque, Centre de ressources historiques.
* ↑ Note de MM. Ouang Te Tchao, Jean Surugue et Mlle Marguerite Perré, Présentée par M. Frédéric Joliot-Curie (1944-01-31). "Sur l'intensité absolue des raies de conversion interne du radioactinium". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 218: 190 – via Gallica.
* ↑ Note de MM. Ouang Te Tchao et Jean Surugue, Présentée par M. Frédéric Joliot-Curie (1944-04-03). "Sur le rayonnement γ de faible energie du radioactinium". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 218: 591 – via Gallica.
* ↑ Note de Mme Eliane Montel et M. Ouang Te Tchao, Présentée par M. Frédéric Joliot-Curie (1951-04-23). "Sur l'analyseur de Paul Langevin pour l'étude des mobilités des ions gazeux". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 232: 1543.
* ↑ Ouang, Te-Tchao; Montel, Eliane (1954-07-01). "Sur la mobilité des ions dans l'air". Journal de Physique et le Radium (in French). 15 (7–9): 586–587. doi:10.1051/jphysrad:01954001507-9058601. ISSN 0368-3842. S2CID 98731837.
* ↑ Ouang, Te-Tchao; Montel, Eliane; Pannetier, P. (1953-11-01). "Sur un électromètre monofilaire de grande sensibilité" (PDF). Journal de Physique et le Radium (in French). 14 (11): 627–629. doi:10.1051/jphysrad:019530014011062700. ISSN 0368-3842. S2CID 97315182.
* ↑ Note de M. Ouang Te-Tchao, présentée par M. Paul Langevin (1946-04-15). "Sur l'absorption des ondes ultrasonores par le sulfure de carbone". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 222: 1215 – via Gallica.
* ↑ Note de M. Ouang Te-Tchao, Présentée par M. Paul Langevin (1946-05-13). "Sur la dispersion des ondes ultrasonores par le sulfure de carbone". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 222: 1165 – via Gallica.
* ↑ Ouang, Te-Tchao (1954-10-01). "Sur la mesure de la vitesse des ultrasons dans les liquides par des indicateurs radioactifs". Journal de Physique et le Radium (in French). 15 (10): 697. doi:10.1051/jphysrad:019540015010069701. ISSN 0368-3842. S2CID 97119742.
* ↑ Note de Ouang Te-Tchao, presentée par M. Jean Cabannes (1950-04-03). "Sur la photophorèse négative". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 230: 1518 – via Gallica.
* ↑ Note de M. Pierre Tauzin, presentée par M. Aimé Cotton (1951-02-05). "Théorie de la photophorèse positive et négative". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 232: 493 – via Gallica.
* ↑ Note de Ouang Te-Tchao, presentée par M. Jean Cabannes (1952-03-31). "Optique - Expériences et remarques sur la photophorèse". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 234: 1542 – via Gallica.
* ↑ Note de M. Pierre Tauzin, presentée par M. Eugène Darmois (1952-06-04). "La photophrèse négative et ses rapports avec une expérience radiométrique récente". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 234: 2265 – via Gallica.
* ↑ Note de M. Ouang Te-Tchao et Mme Eliane Montel, présentée par M. Jean Cabannes (1953-09-28). "Action des rayons β de 204Tl et de 90Sr sur les films photographiques ordinaires". Comptes rendus hebdomadaires des séances de l'Académie des sciences. 237: 800 – via Gallica.
* ↑ Te-Tchao, Ouang (1956-12-01). "Sur la mesure d'épaisseur des feuilles par l'absorption des rayons β émis par 60Co, 204Tl, 90Sr, et 106Ru" (PDF). Journal de Physique et le Radium (in French). 17 (12): 1019–1020. doi:10.1051/jphysrad:0195600170120101901. ISSN 0368-3842.
* ↑ Zak, Sonia (2000). Ouang Te Tchao. Paris, France: Causette. ISBN 978-2913430013.
* ↑ 高天赋. "德高昭然──纪念汪德昭院士--《应用声学》1999年04期". www.cnki.com.cn.
* ↑ Liu Zhenkun, Liu Tianming (2008). WANG Dezhao. Beijing, China: Gold Wall Press. pp. 131–138. ISBN 978-7-80251-038-8.
* 1 2 3 "Wang Dezhao". www.hlhl.org.cn.
* ↑ "《汪德昭院士文集》介绍 1995". 中国科学院院士文库.
* ↑ 侯自强; 彭汉民等 (1995). 汪德昭文集. Beijing, China: Institute of Acoustics, CAS.
* ↑ "《英汉声学词汇》介绍 1982". 中国科学院院士文库.
* ↑ "《法汉水声学词汇》介绍 1986". 中国科学院院士文库.
* ↑ "《水声学》介绍 1981". 中国科学院院士文库.
* ↑ Dezhao, Wang; Erchang, Shang (1981). Underwater Acoustics《水声学》. Beijing, China: Science Press. ISBN 9787030380425.
* ↑ "Prix et Médailles de la S.F.A." www.sfa.asso.fr. Retrieved 2019-01-17.