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Mach's principle

(Encyclopedia)Mach's principle mäks [key] [for E. Mach], assertion that the inertial effects of mass are not innate in a body, but arise from its relation to the totality of all other masses, i.e., to the universe...

superfluidity

(Encyclopedia)superfluidity, tendency of liquid helium below a temperature of 2.19K to flow freely, even upward, with little apparent friction. Helium becomes a liquid when it is cooled to 4.2K. Special methods...

tracer

(Encyclopedia)tracer, an identifiable substance used to follow the course of a physical, chemical, or biological process. In chemistry the ideal tracer has the same chemical properties as the molecule it replaces a...

rhenium

(Encyclopedia)rhenium rēˈnēəm [key], metallic chemical element; symbol Re; at. no. 75; at. wt. 186.207; m.p. about 3,180℃; b.p. about 5,625℃; sp. gr. 21.02 at 20℃; valence −1, +2, +3, +4, +5, +6, or +7....

Dubos, René Jules

(Encyclopedia)Dubos, René Jules rənāˈ zhül dübōˈ [key], 1901–82, American bacteriologist, b. France, Ph.D. Rutgers, 1927. He joined the Rockefeller Institute (now Rockefeller Univ.) in 1927 and became pro...

Heeger, Alan Jay

(Encyclopedia)Heeger, Alan Jay, 1936–, American physicist and chemist, b. Sioux City, Iowa, Ph.D. Univ. of California, Berkeley, 1961. Heeger has held faculty positions at the Univ. of Pennsylvania (1962–82) an...

nail, in carpentry

(Encyclopedia)nail, metal pin driven by force applied at one end into pieces of material, usually wood, to join them together. The strength of a nailed joint depends on the properties of the wood, the type and numb...

Smith, Michael

(Encyclopedia)Smith, Michael, 1932–2000, British-born Canadian biochemist, Ph.D. Univ. of Manchester, 1956. Smith was a researcher at the Univ. of British Columbia from 1961 until his death in 2000. He shared the...

sodium nitrate

(Encyclopedia)sodium nitrate, chemical compound, NaNO3, a colorless, odorless crystalline compound that closely resembles potassium nitrate (saltpeter or niter) in appearance and chemical properties. It is soluble ...

Prelog, Vladimir

(Encyclopedia)Prelog, Vladimir vlädyēˈmĭr prāˈlôg [key], 1906–98, Swiss chemist, b. Sarejevo, Austria-Hungary (now in Bosnia and Herzegovina). Educated in Prague, he worked in Yugoslavia until the German i...