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anthracene

(Encyclopedia)CE5 anthracene ănˈthrəsēn [key], C14H10, solid organic compound derived from coal tar. It melts at 218℃ and boils at 354℃. When pure it is colorless and has a violet fluorescence; it darken...

Grünberg, Peter Andreas

(Encyclopedia)Grünberg, Peter Andreas pāˈtər ändrāˈäs grünbĕrkˈ [key], 1939–2018 German physicist, b. Pilsen, Germany (now Plzeň, Czech Republic). After receiving his Ph.D. at the Darmstadt Univ. of T...

silver chloride

(Encyclopedia)silver chloride, chemical compound, AgCl, a white cubic crystalline solid. It is nearly insoluble in water but is soluble in a water solution of ammonia, potassium cyanide, or sodium thiosulfate (“h...

adhesion and cohesion

(Encyclopedia)adhesion and cohesion, attractive forces between material bodies. A distinction is usually made between an adhesive force, which acts to hold two separate bodies together (or to stick one body to anot...

aerosol dispenser

(Encyclopedia)aerosol dispenser, device designed to produce a fine spray of liquid or solid particles that can be suspended in a gas such as the atmosphere. The dispenser commonly consists of a container that holds...

arsenic

(Encyclopedia)arsenic ärˈsənĭk [key], a semimetallic chemical element; symbol As; at. no. 33; at. wt. 74.92160; m.p. 817℃ (at 28 atmospheres pressure); sublimation point 613℃; sp. gr. (stable form) 5.73; va...

semiconductor

(Encyclopedia)CE5 N-type and P-type crystals: In a pure silicon crystal each silicon atom (Si) is surrounded by four valence electrons. In the N-doped semiconductor, illustrated in the left-hand figure, some sil...

carbon dioxide

(Encyclopedia)carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. It does not bur...

Newfoundland, breed of dog

(Encyclopedia)Newfoundland, breed of massive, powerful working dog developed in Newfoundland, probably in the 17th cent., and later perfected in England. It stands from 25 to 28 in. (63.5–71.1 cm) high at the sho...

molly

(Encyclopedia)molly or mollie, New World fish of the genus Poecilia, which includes the guppy or rainbow fish, Poecilia reticulata. Mollies, which are related to the killifishes, are found from the E and central Un...