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ultrasonics
(Encyclopedia)ultrasonics, study and application of the energy of sound waves vibrating at frequencies greater than 20,000 cycles per second, i.e., beyond the range of human hearing. The application of sound energy...baryon
(Encyclopedia)baryon bârˈēŏnˌ [key] [Gr.,=heavy], class of elementary particles that includes the proton, the neutron, and a large number of unstable, heavier particles, known as hyperons. From a technical poi...Rosenberg Case
(Encyclopedia)Rosenberg Case, in U.S. history, a lengthy and controversial espionage case. In 1950, the Federal Bureau of Investigation arrested Julius Rosenberg (1918–53), an electrical engineer who had worked (...polonium
(Encyclopedia)polonium pəlōˈnēəm [key], radioactive chemical element; symbol Po; at. no. 84; mass no. of most stable isotope 209; m.p. 254℃; b.p. 962℃; sp. gr. about 9.4; valence +2 or +4. Polonium is an e...Gorbachev, Mikhail Sergeyevich
(Encyclopedia)Gorbachev, Mikhail Sergeyevich mēkhəyēlˈ sĭrgāˈyəvich gərbəchofˈ ...force
(Encyclopedia)force, commonly, a “push” or “pull,” more properly defined in physics as a quantity that changes the motion, size, or shape of a body. Force is a vector quantity, having both magnitude and dir...Marshall Islands
(Encyclopedia)Marshall Islands, officially Republic of the Marshall Islands, independent nation (2015 est. pop. 53,000), in the central Pacific. The Marshalls extend over a 700-mi (1,130-km) area and comprise two m...Foreign Ministers, Council of
(Encyclopedia)Foreign Ministers, Council of, organization of the foreign ministers of the World War II Allies—the United States, Great Britain, France, and the USSR—that, in a long series of meetings, attempted...Côte d'Ivoire
(Encyclopedia)CE5 Côte d'Ivoire kōt dēvwärˈ [key] or Ivory Coast, officially Republic of Côte d'Iv...Nevada
(Encyclopedia)CE5 Nevada nəvădˈə, –vä– [key], far western state of the United States. It is bordered by Utah (E), Arizona (SE), California (SW, W), and Oregon and Idaho (N). In the 20th cent. the ...Browse by Subject
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