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optical activity

(Encyclopedia)optical activity, the ability of asymmetric compounds to rotate the orientation of planar polarized light. Such compounds and their mirror images are know as enantiomers, or optical isomers. Although ...

MacDiarmid, Alan Graham

(Encyclopedia)MacDiarmid, Alan Graham, 1927–2007, American chemist, b. Masterton, New Zealand, Ph.D. Univ. of Wisconsin, Madison, 1953, Ph.D. Cambridge, 1955. MacDiarmid was on the faculty at the Univ. of Pennsyl...

Whittingham, Michael Stanley

(Encyclopedia)Whittingham, Michael Stanley, 1941–, British-American chemist, Ph.D. Oxford, 1968. Whittingham worked for Exxon Research & Engineering from 1972 to 1984, then joined Schlumberger Ltd. In 1988, h...

Walker, Sir John Ernest

(Encyclopedia)Walker, Sir John Ernest, 1941–, English biochemist, Ph.D. Oxford, 1969. He has been a researcher at the Medical Research Council Laboratory of Molecular Biology in Cambridge since 1974. In 1997 Walk...

Rabi, Isidor Isaac

(Encyclopedia)Rabi, Isidor Isaac rŏbˈē [key], 1898–1988, American physicist, b. Austria, grad. Cornell, 1919, Ph.D. Columbia, 1927. A teacher at Columbia from 1929, he became professor of physics in 1937. He i...

Sancar, Aziz

(Encyclopedia)Sancar, Aziz, 1946–, Turkish-American biochemist and molecular biologist, M.D. Istanbul Univ., 1969, Ph.D. Univ. of Texas at Dallas, 1977. From 1977to 1982, Sancar was a researcher at the Yale Schoo...

Gerhardt, Charles Frédéric

(Encyclopedia)Gerhardt, Charles Frédéric shärl frādārēkˈ zhārärˈ [key], 1816–56, French chemist, b. Strasbourg. He revived the theory of acid radicals, which he called the theory of residues, and did va...

heat capacity

(Encyclopedia)heat capacity or thermal capacity, ratio of the change in heat energy of a unit mass of a substance to the change in temperature of the substance; like its melting point or boiling point, the heat cap...

Pauling, Linus Carl

(Encyclopedia)Pauling, Linus Carl pôˈlĭng [key], 1901–94, American chemist, b. Portland, Oreg. He was one of the few recipients of two Nobel Prizes, winning the chemistry award in 1954 and the peace prize in 1...

friction

(Encyclopedia)friction, resistance offered to the movement of one body past another body with which it is in contact. In certain situations friction is desired. Without friction the wheels of a locomotive could not...