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hydrogen bomb

(Encyclopedia)hydrogen bomb or H-bomb, weapon deriving a large portion of its energy from the nuclear fusion of hydrogen isotopes. In an atomic bomb, uranium or plutonium is split into lighter elements that togethe...

Defense Advanced Research Projects Agency

(Encyclopedia)Defense Advanced Research Projects Agency (DARPA), U.S. government agency administered by the Department of Defense (see Defense, United States Department of). It was established in 1958, in reaction ...

Richter, Burton

(Encyclopedia)Richter, Burton rĭkˈtər [key], 1931–2018, American physicist, b. New York City, Ph.D. Massachusetts Institute of Technology, 1956. A professor at Stanford, Richter designed and built a particle a...

Seaborg, Glenn Theodore

(Encyclopedia)Seaborg, Glenn Theodore sēˈbôrg [key], 1912–99, American chemist, b. Ishpeming, Mich., grad. Univ. of California at Los Angeles, 1934, Ph.D. Univ. of California at Berkeley, 1937. In 1939, he beg...

fusion

(Encyclopedia)fusion, in physics. 1 The change of a substance from the solid to the liquid state, also known as melting. The heat given up by a unit mass of a substance during fusion is called the latent heat of fu...

Centers for Disease Control and Prevention

(Encyclopedia)Centers for Disease Control and Prevention (CDC), agency of the U.S. Public Health Service since 1973, with headquarters in Atlanta; it was established in 1946 as the Communicable Disease Center. The ...

Voice of America

(Encyclopedia)Voice of America, broadcasting service of the United States Information Agency, est. 1942. Originally set up as a means of fighting the cold war, the Voice of America produces and broadcasts radio pro...

Conant, James Bryant

(Encyclopedia)Conant, James Bryant kōˈnənt [key], 1893–1978, American educator, chemist, and diplomat, b. Dorchester, Mass., grad. Harvard (B.A., 1913; Ph.D., 1916). Except for a brief period in the army (1917...

Brahic, André Fernand

(Encyclopedia)Brahic, André Fernand, 1942–2016, French astrophysicist, b. Paris. He was introduced to astrophysics by Evry Schatzman, a leading French theoretician, and obtained his doctorate from the Univ. of P...

maser

(Encyclopedia)maser māˈzər [key], device for creation, amplification, and transmission of an intense, highly focused beam of high-frequency radio waves. The name maser is an acronym for microwave amplification b...