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radio astronomy

(Encyclopedia)radio astronomy, study of celestial bodies by means of the electromagnetic radio frequency waves they emit and absorb naturally. Radio waves also come from outside the Milky Way. These extragalact...

Dewar, Sir James

(Encyclopedia)Dewar, Sir James dyo͞oˈər [key], 1842–1923, British chemist and physicist, b. Scotland. He was professor of chemistry (from 1877) at the Royal Institution, London, and later was director of the D...

aldehyde

(Encyclopedia)CE5 Aldehydes aldehyde ălˈdəhīd [key] [alcohol + New Lat. dehydrogenatus=dehydrogenated], any of a class of organic compounds that contain the carbonyl group, >C=-->O, and in which t...

activation energy

(Encyclopedia)CE5 Energy profile of an exothermic reaction: Although the total energy of the products is less than that of the reactants, the activation energy must be added to weaken or break existing bonds bef...

combining weight

(Encyclopedia)combining weight, the proportion (by weight) in which a chemical element combines with other elements to form compounds. The determination of combining weights was a very important part of early chemi...

Bosch, Carl

(Encyclopedia)Bosch, Carl, 1874–1940, German chemist and engineer, Ph.D. Univ. of Leipzig, 1898. In 1899, Bosch began working as a chemist for BASF, which merged with six other German chemical firms to become I. ...

Michael, king of Romania

(Encyclopedia)Michael, 1921–2017, king of Romania (1927–30, 1940–47). His father, Prince Carol (later Carol II), renounced his right of succession in 1925, and young Michael ascended the throne under a regenc...

mass spectrograph

(Encyclopedia)mass spectrograph, device used to separate electrically charged particles according to their masses; a form of the instrument known as a mass spectrometer is often used to measure the masses of isotop...

thermionic emission

(Encyclopedia)thermionic emission thûrmˌīŏnˈĭk [key], emission of electrons or ions by substances that are highly heated, the charged particles being called thermions. The number of thermions emitted increase...

Tsien, Roger Yonchien

(Encyclopedia)Tsien, Roger Yonchien, 1952–2016, American biochemist, b. New York City, Ph.D. Cambridge, 1977. Tsien was a researcher at Cambridge (1977–81) and a professor at the Univ. of California, Berkeley (...