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complementarity principle

(Encyclopedia)complementarity principle, physical principle enunciated by Niels Bohr in 1928 stating that certain physical concepts are complementary. If two concepts are complementary, an experiment that clearly i...

sunstone

(Encyclopedia)sunstone. 1 Crystal mineral thought by some to have been used by the Vikings as an aid to navigation, especially in conditions of low visibility due to clouds or fog when the position of the sun was u...

solid-state physics

(Encyclopedia)solid-state physics, study of the properties of bulk matter rather than those of the individual particles that compose it. Solid-state physics is concerned with the properties exhibited by atoms and m...

kaolinite

(Encyclopedia)kaolinite kāˈəlĭnīt [key], clay mineral crystallizing in the monoclinic system and forming the chief constituent of china clay and kaolin. It is a hydrous aluminum silicate commonly formed by the...

Kosterlitz, John Michael

(Encyclopedia)Kosterlitz, John Michael, 1943–, British physicist, b. Scotland, Ph.D. Oxford, 1969. He was on the faculty at the Univ. of Birmingham, England, from 1974 to 1982, when he became a professor at Brown...

Pople, Sir John Anthony

(Encyclopedia)Pople, Sir John Anthony pōpˈəl [key], 1925–2004, British computational chemist. Trained as a mathematician at Cambridge (B.A. 1946, Ph.D. 1951), he worked at Cambridge (1951–58) and England's N...

nonmetal

(Encyclopedia)nonmetal, chemical element possessing certain properties by which it is distinguished from a metal. In general, this distinction is drawn on the basis that a nonmetal tends to accept electrons and for...

alloy

(Encyclopedia)alloy ălˈoi, əloiˈ [key] [O. Fr.,=combine], substance with metallic properties that consists of a metal fused with one or more metals or nonmetals. Alloys may be a homogeneous solid solution, a he...

Ketterle, Wolfgang

(Encyclopedia)Ketterle, Wolfgang, 1957–, German physicist, Ph.D. Max Planck Institute for Quantum Optics, Garching, Germany, 1986. He has been a professor at Massachusetts Institute of Technology since 1990. Kett...

stellar structure

(Encyclopedia)stellar structure, physical properties of a star and the processes taking place within it. Except for that of the sun, astronomers must draw their conclusions regarding stellar structure on the basis ...