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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...

zirconium

(Encyclopedia)zirconium zərkōˈnēəm [key], metallic chemical element; symbol Zr; at. no. 40; at. wt. 91.224; m.p. about 1,852℃; b.p. 4,377℃; sp. gr. 6.5 at 20℃; valence +2, +3, or +4. Zirconium is a very ...

Bernoulli

(Encyclopedia)Bernoulli or Bernouilli both: bĕrno͞oyēˈ [key], name of a family distinguished in scientific and mathematical history. The family, after leaving Antwerp, finally settled in Basel, Switzerland, whe...

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...

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...

mercuric chloride

(Encyclopedia)mercuric chloride or mercury (II) chloride, chemical compound, HgCl2, a white powder of colorless rhombohedral crystals, somewhat soluble in water. It is also called bichloride of mercury or corrosive...

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...

Krebs, Sir Hans Adolf

(Encyclopedia)Krebs, Sir Hans Adolf krĕbz, krĕps [key], 1900–1981, English biochemist, b. Germany, M.D. Univ. of Hamburg, 1925. He taught at Cambridge and at the Univ. of Sheffield and after 1954 was professor ...