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High Temperature Superconductors
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13321 |
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Section : |
NATURAL SCIENCE
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| Issue
Date : |
10 / 1987 |
3,813 Words |
| Author
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Charles Sheffield
Charles Sheffield is the author of several science fiction
novels as well as numerous articles and essays on physics and
space science. |
It is rare for physics research to be considered newsworthy, rarer still for it to appear on the front pages. Rarest of all, perhaps, is for a conference on that research to be an event at which the president of the United States, serving as keynote speaker and accompanied by the secretary of state, the secretary of defense, and the secretary of energy, announces a comprehensive 11-point initiative to promote U.S. competitiveness in the field of high-temperature superconductors. Yet this is exactly what happened in Washington on July 28, 1987.
Some other countries are showing just as much national interest as the United States, with particularly strong programs in Japan and China. A true technological race is in progress. The new field of high-temperature superconductivity has broken all the usual rules for scientific development, in rate of progress, public interest, and claims of potential long-term effects. Many scientists regard the discovery of high-temperature superconductors as the most important technological advance of the second half of the twentieth century, with the potential for profound influences on everything from computer design to medical diagnosis to transportation systems to power transmission to the international balance of trade.
At the same time, high-temperature superconductivity remains a recondite phenomenon. The path to understanding it has followed a convoluted course, leading down close to absolute zero and the coldest temperatures ever achieved by making. It is also intertwined with one of the great twentieth-century revolutions in scientific thought - quantum theory.
Superconductivity
In 1908, the Dutch scientist Kamerlingh Onnes was approaching the end of a long quest. Every known gas had been liquefied, with the exception of helium. In his attempt to liquefy that gas, Kamerlingh Onnes achieved lower and lower temperatures, working steadily toward absolute zero, a temperature of -273.16º C, where all molecular motion ceases.
When Onnes finally succeeded in liquefying helium in 1908, he understood his earlier failures. Helium remains a gas until -268.9º C - only 4.2º above absolute zero.
Having produced liquid helium, Onnes used it to conduct other low-temperature investigations. In 1911, he examined the electrical properties of materials immersed in a bath of liquid helium and discovered that certain
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