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maser

(Encyclopedia)maser māˈzər [key], device for creation, amplification, and transmission of an intense, highly focused beam of high-frequency radio waves. The name maser is an acronym for microwave amplification b...

particle detector

(Encyclopedia)CE5 Particle detector—Bubble chamber: A. Pressure drops as piston is raised; B. Charged particles passing through chamber ionize atoms in liquid; C. Bubbles form around atoms and form visible tra...

superconductivity

(Encyclopedia)superconductivity, abnormally high electrical conductivity of certain substances. The phenomenon was discovered in 1911 by Heike Kamerlingh Onnes, who found that the resistance of mercury dropped sudd...

radio

(Encyclopedia)CE5 A. AM transmitter B. AM receiver radio, transmission or reception of electromagnetic radiation in the radio frequency range. The term is commonly applied also to the equipment used, especially...

insecticides

(Encyclopedia)insecticides, chemical, biological, or other agents used to destroy insect pests; the term commonly refers to chemical agents only. The liabilities of chemical insecticides have encouraged interest ...

Guangzhou

(Encyclopedia)Guangzhou kănˌtŏnˈ, kănˈtŏnˌ [key], city (1994 est. pop. 3,113,800), capital of Guangdong prov., S China, a major deepwater port on the Pearl River delta. Guangzhou became a part of China in...

Saarland

(Encyclopedia)Saarland zärˈlänt [key], state (1994 pop. 1,080,000), 991 sq mi (2,567 sq km), SW Germany; formerly called the Saar or the Saar Territory. Saarbrücken is the capital; other cities include Völklin...

village

(Encyclopedia)village, small rural population unit, held together by common economic and political ties. Based on agricultural production, a village is smaller than a town and has been the normal unit of community ...

ignition

(Encyclopedia)CE5 Ignition system ignition, apparatus for igniting a combustible mixture. The German engineer Nikolaus A. Otto, in his first gas engine, used flame ignition; another method was heating a metal t...

Ptolemaic system

(Encyclopedia)Ptolemaic system tŏlˌəmāˈĭk [key], historically the most influential of the geocentric cosmological theories, i.e., theories that placed the earth motionless at the center of the universe with a...