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praseodymium

(Encyclopedia)praseodymium prāˌzēōdĭmˈēəm, –sēō– [key] [Gr., =green twin], metallic chemical element; symbol Pr; at. no. 59; at. wt. 140.90765; m.p. 931℃; b.p. 3,512℃; sp. gr. about 6.8; valence +...

protactinium

(Encyclopedia)protactinium prōˌtăktĭnˈēəm [key], radioactive chemical element; symbol Pa; at. no. 91; mass number of most stable isotope 231; m.p. greater than 1,600℃; b.p. 4,026℃; sp. gr. 15.37 (calcula...

Plücker, Julius

(Encyclopedia)Plücker, Julius yo͞oˈlyo͝os plüˈkər [key], 1801–68, German mathematician and physicist. He became professor of mathematics (1836) and of physics (1847) at the Univ. of Bonn. He is known for h...

Chongqing

(Encyclopedia)Chongqing cho͞ongˈkĭngˈ [key], city and independent municipality, 592 sq mi (1,534 sq km), in SE ...

hardening

(Encyclopedia)hardening, in metallurgy, treatment of metals to increase their resistance to penetration. A metal is harder when it has small grains, which result when the metal is cooled rapidly. Sometimes small ar...

Anhui

(Encyclopedia)Anhui or Anhwei both: änˈhwāˈ [key], province, c.55,000 sq mi (142,450 sq km), E central China. Hefei is the capital. Anhui may be divided into two climatic areas. The north...

Copiapó

(Encyclopedia)Copiapó kōpyäpōˈ [key], city (1990 est. pop. 79,268), capital of Atacama region, N central Chile, on the Copiapó River. An industrial city at the southern edge of the Atacama Desert, Copiapó ha...

Ibaraki

(Encyclopedia)Ibaraki ēbäˈräkē [key], prefecture, 2,352 sq mi (6,092 sq km), central Honshu, Japan. ...

Anaconda, city, United States

(Encyclopedia)Anaconda ănəkŏnˈdə [key], city (2020 pop. 9,162), seat of Deer Lodge co., SW Mont.; inc. 1887. Marcus Daly chose this place (1883) for the Anaconda Copper Mining Company's ...

patina

(Encyclopedia)patina pătˈənə [key], coating of carbonate of copper on articles of copper or bronze, formed after long exposure to a moist atmosphere or burial in the earth. Although commonly green, patina varie...