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United Nations

(Encyclopedia)CE5 CE5 United Nations (UN), international organization established immediately after World War II. It replaced the League of Nations. In 1945, when the UN was founded, there were 51 members; 193...

Armstrong, Lance

(Encyclopedia)Armstrong, Lance, 1971–, American cyclist, b. Dallas, Tex. He won (1991) the U.S. amateur cycling championship, turned professional (1992), and by the mid-1990s had won the Tour DuPont twice and was...

African Union

(Encyclopedia)African Union (AU), international organization established in 2002 by the nations of the former Organization of African Unity (OAU). The AU is the successor organization to the OAU, with greater power...

Walton, Ernest Thompson Sinton

(Encyclopedia)Walton, Ernest Thompson Sinton, 1903–95, Irish physicist, educated at Methodist College (Belfast), Trinity College (Dublin), and Cambridge. He became a fellow of Trinity College in 1934 and professo...

Dalton, John

(Encyclopedia)Dalton, John dôlˈtən [key], 1766–1844, English scientist. He revived the atomic theory (see atom), which he formulated in the first volume of his New System of Chemical Philosophy (2 vol., 1808�...

phosphorescence

(Encyclopedia)phosphorescence fŏsˌfərĕsˈəns [key], luminescence produced by certain substances after absorbing radiant energy or other types of energy. Phosphorescence is distinguished from fluorescence in th...

Kourou

(Encyclopedia)Kourou, town and commune (2007 pop. 25,918), N French Guiana, on the coast 26 mi (42 km) NW of Cayenne. A rocket-launching base, the Guiana Space Center, is mainly in the commune near the town; the So...

power, in physics

(Encyclopedia)power, in physics, time rate of doing work or of producing or expending energy. The unit of power based on the English units of measurement is the horsepower, devised for describing mechanical power b...

prime mover

(Encyclopedia)prime mover: see energy, sources of. ...

Lenz's law

(Encyclopedia)Lenz's law, physical law, discovered by the German scientist H. F. E. Lenz in 1834, that states that the electromotive force (emf) induced in a conductor moving perpendicular to a magnetic field tends...