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thermodynamics

(Encyclopedia)thermodynamics, branch of science concerned with the nature of heat and its conversion to mechanical, electric, and chemical energy. Historically, it grew out of efforts to construct more efficient he...

libido

(Encyclopedia)libido lĭbēˈdō, –bīˈ– [key] [Lat.,=lust], psychoanalytic term used by Sigmund Freud to identify instinctive energy with the sex instinct. For Freud, libido is the generalized sexual energy o...

Compton effect

(Encyclopedia)Compton effect [for A. H. Compton], increase in the wavelengths of X rays and gamma rays when they collide with and are scattered from loosely bound electrons in matter. This effect provides strong ve...

Carnot, Nicolas Léonard Sadi

(Encyclopedia)Carnot, Nicolas Léonard Sadi kärnōˈ [key], 1796–1832, French physicist, a founder of modern thermodynamics; son of Lazare N. M. Carnot. His famous work on the motive power of heat (Réflexions ...

Chlorophyta

(Encyclopedia)Chlorophyta klōrŏfˈətə [key], phylum (division) of the kingdom Protista consisting of the photosynthetic organisms commonly known as green algae. The organisms are largely aquatic or marine. The ...

joule

(Encyclopedia)joule jo͞ol, joul [key], abbr. J, unit of work or energy in the mks system of units, which is based on the metric system; it is the work done or energy expended by a force of 1 newton acting through ...

Schlesinger, James Rodney

(Encyclopedia)Schlesinger, James Rodney, 1929–2014, U.S. secretary of defense (1973–75) and secretary of energy (1977–79), b. New York City. After graduating from Harvard (A.B., 1950; A.M., 1952; Ph.D., 1956)...

beta particle

(Encyclopedia)beta particle, one of the three types of radiation resulting from natural radioactivity. Beta radiation (or beta rays) was identified and named by E. Rutherford, who found that it consists of high-spe...

adenosine triphosphate

(Encyclopedia)CE5 Adenosine triphosphate (ATP) adenosine triphosphate (ATP) ədĕnˈəsēn trīˌfŏsˈfāt [key], organic compound composed of adenine, the sugar ribose, and three phosphate groups. ATP serves ...

Mastigophora

(Encyclopedia)Mastigophora măsˌtĭgŏfˈərə [key], phylum of unicellular heterotrophic protozoans of the kingdom Protista. Most of the approximately 1,500 species of Mastigophora are propelled by one or more fl...