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luminescence

(Encyclopedia)luminescence, general term applied to all forms of cool light, i.e., light emitted by sources other than a hot, incandescent body, such as a blackbody radiator. Luminescence is caused by the movement ...

Barton, Derek H. R.

(Encyclopedia)Barton, Derek H. R., 1918–98, British chemist, b. Gravesend, England, grad. Imperial College of Science and Technology (B.S. 1940, Ph.D. 1942, D.Sc. 1949). He was on the faculty of Imperial College ...

thermionic emission

(Encyclopedia)thermionic emission thûrmˌīŏnˈĭk [key], emission of electrons or ions by substances that are highly heated, the charged particles being called thermions. The number of thermions emitted increase...

poisonous plant

(Encyclopedia)poisonous plant, any plant possessing a property injurious to man or animal. Plants may be poisonous to the touch (e.g., poison ivy, poison sumac), or orally toxic (e.g., poison hemlock, deadly amanit...

Bakelite

(Encyclopedia)Bakelite bāˈkəlīt [key] [for its inventor, L. H. Baekeland], synthetic thermosetting resin. It has been widely used both alone, to form whole objects, and in combination with other materials, as a...

limonite

(Encyclopedia)limonite hĕmˈətīt, hēˈ– [key], yellowish to dark brown mineral, a hydrated oxide of iron, FeO(OH)·nH2O, occurring commonly in deposits of secondary origin, i.e., those formed by the alteratio...

arsenopyrite

(Encyclopedia)arsenopyrite mĭsˈpĭkəl [key], silver-white to steel-gray mineral with the metallic luster characteristic of a pyrite. It is a sulfarsenide of iron, FeAsS, crystallizing in the orthorhombic system ...

Hoffmann, Friedrich

(Encyclopedia)Hoffmann, Friedrich hôfˈmän [key], 1660–1742, German physician. He taught and practiced at Halle from 1693. He studied and wrote on such varied topics as pediatrics, mineral waters, and meteorol...

heat exhaustion

(Encyclopedia)heat exhaustion, condition caused by overexposure to sunlight or another heat source and resulting in dehydration and salt depletion, also known as heat prostration. The symptoms are severe headaches,...

Joplin

(Encyclopedia)Joplin jŏpˈlĭn [key], city (1990 pop. 40,961), Jasper and Newton counties, SW Mo., at the edge of the Ozarks; settled c.1839, inc. 1873. It is a railroad center, the shipping and processing point o...