Kamen, Martin David

(kā`mən), 1913–2002, American biochemist, b. Toronto, Canada, grad. Univ. of Chicago (B.S., Ph.D. 1937). He discovered carbon-14, the radioactive isotoperadioactive isotope
or radioisotope,
natural or artificially created isotope of a chemical element having an unstable nucleus that decays, emitting alpha, beta, or gamma rays until stability is reached.
..... Click the link for more information. of carboncarbon
[Lat.,=charcoal], nonmetallic chemical element; symbol C; at. no. 6; interval in which at. wt. ranges 12.0096–12.0116; m.p. about 3,550&degC;; graphite sublimes about 3,375&degC;; b.p. 4,827&degC;; sp. gr. 1.8–2.1 (amorphous), 1.9–2.3 (graphite), 3.
..... Click the link for more information. used to trace biochemical pathways and mechanisms and to date archeological and anthropological objects (see datingdating,
the determination of the age of an object, of a natural phenomenon, or of a series of events. There are two basic types of dating methods, relative and absolute.
..... Click the link for more information. ). He also carried out extensive research that underlies much of our understanding of the process of photosynthesisphotosynthesis
, process in which green plants, algae, and cyanobacteria utilize the energy of sunlight to manufacture carbohydrates from carbon dioxide and water in the presence of chlorophyll. Some of the plants that lack chlorophyll, e.g.
..... Click the link for more information. . Because of his association with Russian consular officials, whom he had met socially, he was declared a security risk in 1944 and dismissed from his job. A few years later, he was brought before the House Un-American Activities CommitteeHouse Un-American Activities Committee
(HUAC), a committee (1938–75) of the U.S. House of Representatives, created to investigate disloyalty and subversive organizations. Its first chairman, Martin Dies, set the pattern for its anti-Communist investigations.
..... Click the link for more information. and his passport was revoked. Kamen spent more than a decade trying to clear his name, but in 1955 he won a libel suit against the Chicago Tribune. He wrote Radiant Science, Dark Politics: A Memoir of the Nuclear Age (1985).

单词	kamen, martin david
释义	Kamen, Martin David Kamen, Martin David (kā`mən), 1913–2002, American biochemist, b. Toronto, Canada, grad. Univ. of Chicago (B.S., Ph.D. 1937). He discovered carbon-14, the radioactive isotoperadioactive isotope or radioisotope, natural or artificially created isotope of a chemical element having an unstable nucleus that decays, emitting alpha, beta, or gamma rays until stability is reached. ..... Click the link for more information. of carboncarbon [Lat.,=charcoal], nonmetallic chemical element; symbol C; at. no. 6; interval in which at. wt. ranges 12.0096–12.0116; m.p. about 3,550&degC;; graphite sublimes about 3,375&degC;; b.p. 4,827&degC;; sp. gr. 1.8–2.1 (amorphous), 1.9–2.3 (graphite), 3. ..... Click the link for more information. used to trace biochemical pathways and mechanisms and to date archeological and anthropological objects (see datingdating, the determination of the age of an object, of a natural phenomenon, or of a series of events. There are two basic types of dating methods, relative and absolute. ..... Click the link for more information. ). He also carried out extensive research that underlies much of our understanding of the process of photosynthesisphotosynthesis , process in which green plants, algae, and cyanobacteria utilize the energy of sunlight to manufacture carbohydrates from carbon dioxide and water in the presence of chlorophyll. Some of the plants that lack chlorophyll, e.g. ..... Click the link for more information. . Because of his association with Russian consular officials, whom he had met socially, he was declared a security risk in 1944 and dismissed from his job. A few years later, he was brought before the House Un-American Activities CommitteeHouse Un-American Activities Committee (HUAC), a committee (1938–75) of the U.S. House of Representatives, created to investigate disloyalty and subversive organizations. Its first chairman, Martin Dies, set the pattern for its anti-Communist investigations. ..... Click the link for more information. and his passport was revoked. Kamen spent more than a decade trying to clear his name, but in 1955 he won a libel suit against the Chicago Tribune. He wrote Radiant Science, Dark Politics: A Memoir of the Nuclear Age (1985).
随便看	bush bitch bush blackberry bush blue lake bushboy bush bread bush brothers banana republic bush buck bushbuck bushbuck antelope bushbucks bushbush virus bush canary bush carpenter bush cat bush chat bush-cheney bush-cheney 2004 bush clinton katrina fund bush clover bush-clovers bushcraft bush cranberry bush cricket bush-cricket bushcricket