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Grand Junction

(Encyclopedia)Grand Junction, city (2020 pop. 65,560), seat of Mesa co., W Colo., at the junction of the Gunnison and Colorado rivers; inc. 1891. The shipping and pro...

radium

(Encyclopedia)radium rāˈdēəm [key] [Lat. radius=ray], radioactive metallic chemical element; symbol Ra; at. no. 88; mass number of most stable isotope 226; m.p. 700℃; b.p. 1,140℃; sp. gr. about 6.0; valence...

actinide series

(Encyclopedia)actinide series, a series of radioactive metallic elements in Group 3 of the periodic table. Members of the series are often called actinides, although actinium (at. no. 89) is not always considered a...

thorium

(Encyclopedia)thorium thôrˈēəm [key] [from Thor], radioactive chemical element; symbol Th; at. no. 90; mass number of most stable isotope 232; m.p. about 1,750℃; b.p. about 4,790℃; sp. gr. 11.7 at 20℃; va...

Hahn, Otto

(Encyclopedia)Hahn, Otto ôˈtō hän [key], 1879–1968, German chemist and physicist. His important contributions in the field of radioactivity include the discovery of several radioactive substances, the develop...

Port Hope

(Encyclopedia)Port Hope, town (1991 pop. 11,505), SE Ont., Canada, on Lake Ontario, E of Toronto. It has a large plant for refining uranium ore and is a summer resort. ...

nuclear energy

(Encyclopedia)CE5 Graph of binding energy per nucleon as a function of mass number nuclear energy, the energy stored in the nucleus of an atom and released through fission, fusion, or radioactivity. In these pr...

U , letter of the alphabet

(Encyclopedia)U, 21st letter of the alphabet, corresponding to the Greek upsilon [Gr.,=u without the aspirate]. Until the late Middle Ages the capital was V, the minuscule u, no distinction being made between the c...

Flinders Ranges

(Encyclopedia)Flinders Ranges, mountain chain, extending 260 mi (418 km) between Lake Torrens and Lake Frome, South Australia state, Australia; rises to 3,900 ft (1,189 m) at St. Mary's Peak. Uranium and copper are...

Pierrelatte

(Encyclopedia)Pierrelatte pyĕrlätˈ [key], town, Drôme dept., SE France. The center of France's nuclear industry, Pierrelatte has a large uranium-producing complex. Other industries include jute weaving and the ...