Chu , Paul Ching-Wu
- (1941–) American physicistChu was born in Hunan, China, but his parents were members of the Nationalist Party and the family fled to Taiwan in 1949 for political reasons. After graduating in physics from Chengkung University, Chu moved to America in 1963 and gained his PhD in 1968 from the University of California, San Diego. After spending some time working for the company AT & T, Chu entered academic life, first at Cleveland State University, and since 1979 as professor of physics at the University of Houston.Much of Chu's work has been in the field of superconductivity. A major breakthrough had been achieved in 1986 when Alex Muller had discovered some materials that become superconductive below the relatively high critical temperature of 35 K (–238°C). This temperature was still too low to be economic. The vital temperature was 77.4 K (–195.8°C) – the temperature below which nitrogen becomes liquid. The aim was to find materials that could be cooled to a superconducting state using relatively cheap liquid nitrogen, rather than the extremely expensive liquid helium (b.p. –268.9°C). Chu was determined that his Houston laboratory would be the first to find a superconductor with a critical temperature above 77.4 K.The superconductor found by Muller was a ceramic material composed of barium, lanthanum, and copper oxide (Ba–La–CuO). Chu began by reproducing Muller's work. He next developed new methods of synthesis for this type of compound and began first to vary the ratio of elements in the compound. Initial results obtained by reducing the amount of copper were encouraging, but could not be repeated. However, at high pressures of 10,000 atmospheres it was possible to increase the critical temperature to about 40 K. Changing the proportions of the elements could raise the temperature to 52.5 K, but this was still at high pressures.The original Muller compound contained three metals in the ratio 2:1:4. Many researchers concentrated on substituting other metals in the same ratio. Copper seemed to play a special bonding role and was judged by Chu to be indispensable. Chu decided to replace the lanthanum with other related lanthanoid elements. One he chose to work with was yttrium (Y). Finally, in January 1987, just a year after Muller's breakthrough, Chu found that the critical temperature of Y1.2Ba0.8CuO4 was 93 K and that the effect was stable and permanent.
Scientists. Academic. 2011.
Look at other dictionaries:
Paul Samuelson — Paul A. Samuelson Neo Keynesian economics Photo taken 1950 (age 35) Born May 15, 1915(1915 05 15) Gary … Wikipedia
Chu Ching-wu — This is a Chinese name; the family name is Chu. Paul C.W. Chu Born February 12, 1941 … Wikipedia
Paul Cohen (mathematician) — Not to be confused with Paul Cohn. Paul J. Cohen Born April 2, 1934(1934 04 02) Long Branch, New Jersey Died March 23, 2007 … Wikipedia
Paul Chun (actor) — Paul Chun Chinese name 秦沛 Chinese name 秦沛 (Traditional) Chinese name 秦沛 (Simplified) Birth name Chiang Ch ang Nien 姜昌年 … Wikipedia
Paul Chu — may refer to:*Chu Ching wu, Paul C.W. Chu, president of The Hong Kong University of Science and Technology *Paul K Chu, professor at City University of Hong Kong *Paul Chu, actor also known as Kong Chu or Paul Chu Kong … Wikipedia
Eric Chu — 朱立倫 PhD 1st Mayor of New Taipei Incumbent Assumed office … Wikipedia
I Ching divination — Among the many forms of divination is a bibliomancy method using the I Ching (易經) or Book of Changes. The book is structured as 32 pairs of hexagrams, divided in half after the first 30. The text was a subject for civil service exams in Imperial… … Wikipedia
Evergreen Mak Cheung-ching — This is a Chinese name; the family name is Mak. Evergreen Mak Chinese name 麥長青 (Traditional) Chinese name 麦长青 (Simplified) Pinyin Mài Chángqīng ( … Wikipedia
Guodian Chu Slips — The Guodian Chu Slips (zh cp|c=郭店楚簡|p=Guōdiàn Chǔjiǎn) were unearthed in 1993 in Tomb no. 1 of the Guodian tombs in Jingmen, Hubei. The archeological team suggested the tomb should be dated to the latter half of the Warring States period (mid 4th … Wikipedia
John Ching Hsiung Wu — [Sometimes erroneously written as John Chin Hsung Wu] (also John C.H. Wu; pinyin: Wu Jingxiong) (born Ningbo 1899 1986) was a Chinese poet, lawyer, and writer. He wrote works in Chinese, English, French, and German on Christian spirituality,… … Wikipedia