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Butte, city, United States

(Encyclopedia)Butte byo͞ot [key], city (2020 pop. 34,494), seat of Silver Bow co., SW Mont.; inc. 1879. It...

lubrication

(Encyclopedia)lubrication, introduction of a substance between the contact surfaces of moving parts to reduce friction and to dissipate heat. A lubricant may be oil, grease, graphite, or any substance—gas, liquid...

ruthenium

(Encyclopedia)ruthenium ro͞othēˈnēəm [key], metallic chemical element; symbol Ru; at. no. 44; at. wt. 101.07; m.p. about 2,310℃; b.p. about 3,900℃; sp. gr. 12.41 at 20℃; valence commonly +2, +3, +4, +6, ...

Buryat Republic

(Encyclopedia)Buryat Republic bo͝oryätˈēə [key], constituent republic (2020 est. pop. 985,431), c.135,600 sq mi ...

technetium

(Encyclopedia)technetium tĕknēˈshēəm [key] [Gr. technetos=artificial], artificially produced radioactive chemical element; symbol Tc; at. no. 43; mass no. of most stable isotope 98; m.p. 2,200℃; b.p. 4,877�...

Khakass Republic

(Encyclopedia)Khakass Republic khəkäsˈēə [key], constituent republic (1990 est. pop. 573,000) 23,900 sq mi (61,900 sq km), S central Siberian Russia, in Krasnoyarsk Territory. Abakan (the capital) and Chernogo...

tungsten

(Encyclopedia)tungsten tŭngˈstən [key] [Swed.,=heavy stone], metallic chemical element; symbol W; at. no. 74; at. wt. 183.84; m.p. about 3,410℃; b.p. 5,660℃; sp. gr. 19.3 at 20℃; valence +2, +3, +4, +5, or...

chromium

(Encyclopedia)chromium krōˈmēəm [key] [Gr.,=color], metallic chemical element; symbol Cr; at. no. 24; at. wt. 51.9961; m.p. about 1,857℃; b.p. 2,672℃; sp. gr. about 7.2 at 20℃; valence +2, +3, +6. Chromiu...

Hainan

(Encyclopedia)Hainan hīˈnänˈ [key], island and province, c.13,100 sq mi (33,940 sq km), China, in the S...

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...

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