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mineral

(Encyclopedia)mineral, inorganic substance occurring in nature, having a characteristic and homogeneous chemical composition, definite physical properties, and, usually, a definite crystalline form. A few of the mi...

palladium, chemical element

(Encyclopedia)palladium [Gr. Pallas, goddess of wisdom], metallic chemical element; symbol Pd; at. no. 46; at. wt. 106.42; m.p. 1,554℃; b.p. 2,970℃; sp. gr. 12.02 at 20℃; valence +2, +3, or +4. Palladium is a...

Paterson

(Encyclopedia)Paterson, city (1990 pop. 140,891), seat of Passaic co., NE N.J., at the falls of the Passaic River; inc. 1851. Founded in 1791 by Alexander Hamilton and others of the Society for Establishing Useful ...

Yokohama

(Encyclopedia)Yokohama yōˌkōhäˈmä [key], city (1990 pop. 3,220,331), capital of Kanagawa prefecture, SE Honshu, Japan, on the western shore of Tokyo Bay. Japan's second largest city and one of its leading sea...

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...

solid

(Encyclopedia)solid, one of the three commonly recognized states in which matter occurs, i.e., that state, as distinguished from liquid and gas, in which a substance has both a definite shape and a definite volume....

photoelectric effect

(Encyclopedia)photoelectric effect, emission of electrons by substances, especially metals, when light falls on their surfaces. The effect was discovered by H. R. Hertz in 1887. The failure of the classical theory ...

Saint-Denis, city, France

(Encyclopedia)Saint-Denis săN-dənēˈ [key], city (1990 pop. 90,806), Seine–Saint-Denis dept., N central France. It is an industrial suburb N of Paris. Metals, chemicals, machinery, electronics, and food produc...

caravan

(Encyclopedia)caravan, group of travelers or merchants banded together and organized for mutual assistance and defense while traveling through unsettled or hostile country. Caravan trade is associated with the hist...

element

(Encyclopedia)CE5 element, in chemistry, a substance that cannot be decomposed into simpler substances by chemical means. A substance such as a compound can be decomposed into its constituent elements by means o...