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dredging

(Encyclopedia)dredging, process of excavating materials underwater. It is used to deepen waterways, harbors, and docks and for mining alluvial mineral deposits, including tin, gold, and diamonds. The Dutch at an ea...

Moorish art and architecture

(Encyclopedia)Moorish art and architecture, branch of Islamic art and architecture developed in the westernmost lands of the Muslims, known as the Maghreb: N Africa and Spain. The Great Mosque at Al Qayrawan in Tun...

Sakha Republic

(Encyclopedia)Sakha Republic yəko͞oˈshēə [key], constituent republic (1995 pop. 1,035,000), c.1,200,000 sq mi (3,108,000 sq km), NE Siberian Russia. Yakutsk is the capital. The Sakha Republic is bounded in the...

semiconductor

(Encyclopedia)CE5 N-type and P-type crystals: In a pure silicon crystal each silicon atom (Si) is surrounded by four valence electrons. In the N-doped semiconductor, illustrated in the left-hand figure, some sil...

Shan State

(Encyclopedia)Shan State shän [key], state (1983 pop. 3,718,706), c.60,000 sq mi (155,400 sq km), E central Myanmar. Taunggyi, the capital, and Lashio are its principal cities. It borders on China in the north, La...

superconductivity

(Encyclopedia)superconductivity, abnormally high electrical conductivity of certain substances. The phenomenon was discovered in 1911 by Heike Kamerlingh Onnes, who found that the resistance of mercury dropped sudd...

Williams, Tennessee

(Encyclopedia)Williams, Tennessee (Thomas Lanier Williams), 1911–83, American dramatist, b. Columbus, Miss., grad. State Univ. of Iowa, 1938. One of America's foremost 20th-century playwrights and the author of m...

manganese

(Encyclopedia)manganese măngˈgənēs, mănˈ– [key] [Lat.,=magnet], metallic chemical element; symbol Mn; at. no. 25; at. wt. 54.93805; m.p. about 1,244℃; b.p. about 1,962℃; sp. gr. 7.2 to 7.45, depending o...

roof

(Encyclopedia)roof, overhead covering of a building with its framework support. Various methods of construction, such as are suited to different climates, have diversified exterior and interior architectural effect...

dentistry

(Encyclopedia)dentistry, treatment and care of the teeth and associated oral structures. Dentistry is mainly concerned with tooth decay, disease of the supporting structures, such as the gums, and faulty positionin...