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equation

(Encyclopedia)equation, in mathematics, a statement, usually written in symbols, that states the equality of two quantities or algebraic expressions, e.g., x+3=5. The quantity x+3, to the left of the equals sign (=...

hydroxide

(Encyclopedia)hydroxide hīdrŏkˈsīd [key], chemical compound that contains the hydroxyl (−OH) radical. The term refers especially to inorganic compounds. Organic compounds that have the hydroxyl radical as a f...

jet propulsion

(Encyclopedia)CE5 Types of jet engines: In the propeller-driven turbine a stream of high-velocity gases provides the power to drive the turbine and turn the propeller. In the jet-driven turbine the stream of gas...

nuclear reactor

(Encyclopedia)CE5 Power reactor system nuclear reactor, device for producing controlled release of nuclear energy. Reactors can be used for research or for power production. A research reactor is designed to pr...

Martin, Archer John Porter

(Encyclopedia)Martin, Archer John Porter, 1910–2002, English biochemist, educated at Cambridge. From 1938 to 1946 he carried on chemical research in the laboratories of the Wool Industries Association at Leeds, Y...

Fitch, Val Logsdon

(Encyclopedia)Fitch, Val Logsdon, 1923–2015, American nuclear physicist, b. Merriman, Neb., Ph.D. Columbia, 1954. During World War II Fitch was drafted into the army and worked on the detonator for the atomic bom...

impressionism, in music

(Encyclopedia)impressionism, in music, a French movement in the late 19th and early 20th cent. It was begun by Debussy in reaction to the dramatic and dynamic emotionalism of romantic music, especially that of Wagn...

hives

(Encyclopedia)hives (urticaria), rash consisting of blotches or localized swellings (wheals) of the skin, caused by an allergic reaction (see allergy). The swelling is caused by distention of the skin capillaries a...

thorium

(Encyclopedia)thorium thôrˈēəm [key] [from Thor], radioactive chemical element; symbol Th; at. no. 90; mass number of most stable isotope 232; m.p. about 1,750℃; b.p. about 4,790℃; sp. gr. 11.7 at 20℃; va...

absorption

(Encyclopedia)absorption [Lat.,=sucking from], taking of molecules of one substance directly into another substance. It is contrasted with adsorption, in which the molecules adhere only to the surface of the second...