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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...

oxidation and reduction

(Encyclopedia)oxidation and reduction, complementary chemical reactions characterized by the loss or gain, respectively, of one or more electrons by an atom or molecule. Originally the term oxidation was used to re...

Alder, Kurt

(Encyclopedia)Alder, Kurt älˈdər [key], 1902–58, German chemist, educated at Berlin and at Kiel. He was on the research staff of the Bayer Dye Works (1936–40) before becoming (1940) professor of chemistry an...

Haworth, Sir Walter Norman

(Encyclopedia)Haworth, Sir Walter Norman, 1883–1950, British chemist, Ph.D. Univ. of Göttingen, 1911. Haworth held academic posts at Imperial College of Science and Technology in London (1911–12), the Univ. of...

Haber, Fritz

(Encyclopedia)Haber, Fritz häˈbər [key], 1868–1934, German chemist. He was a professor of physical chemistry at Karlsruhe and became director of the Kaiser Wilhelm Institute at Dahlem in 1911. During World War...

Meyerhof, Otto

(Encyclopedia)Meyerhof, Otto ôˈtō mīˈərhōf [key], 1884–1951, American physiologist, b. Germany, M.D. Heidelberg, 1909. He was professor at the Univ. of Kiel (1912–24) and at the Univ. of Berlin and direc...

National Institute of Standards and Technology

(Encyclopedia)National Institute of Standards and Technology, governmental agency within the U.S. Dept. of Commerce with the mission of “working with industry to develop and apply technology, measurements, and st...

obsidian

(Encyclopedia)obsidian ŏbsĭdˈēən [key], a volcanic glass, homogeneous in texture and having a low water content, with a vitreous luster and a conchoidal fracture. The color is commonly black, but may be some s...

night blindness

(Encyclopedia)night blindness, inability to see normally in subdued light. It is usually a result of vitamin A deficiency. The rod cells, one of two light-sensitive areas of the retina of the eye, are impaired in t...

Nivernais

(Encyclopedia)Nivernais nēvĕrnāˈ [key], region and former province, central France. It roughly coincides with Nièvre dept. Drained by the Loire and the Yonne, it is a hilly plateau, rising to the Morvan Mts. i...