| 释义 |
van der Waals Physics.|væn də ˈvɑːls|
Also Van der Waals.
The name of Johannes van der Waals (1837–1923), Dutch physicist, used attrib. and in the possessive to designate (a) an equation of state of a gas (proposed by him in 1873) that allows for intermolecular attraction and finite molecular size, viz. (p + a/V2)(V - b) = RT (where p is the pressure, V the volume, R the gas constant, T the absolute temperature, and a and b are constants); (b) short-range attractive forces between uncharged molecules arising from interaction between (actual or induced) electric dipole moments; so van der Waals attraction, etc.
1895C. S. Palmer tr. Nernst's Theoret. Chem. ii. ii. 186 The equation assumes the form (p + a/v2)(v- b) = RT. This is van der Waals' equation of condition. 1923Jrnl. Chem. Soc. CXXIII. 3403 At the critical point in particular, Van der Waals's equation predicts that pv will be 22/3 times as great as the value given by the simple law of Boyle. 1930Engineering 5 Dec. 700/3 There were, further, different types of cohesion forces. (1) Van der Waals cohesion. 1964J. W. Linnett Electronic Struct. Molecules ii. 28 No chemical bond is formed and, except for a weak van der Waals (polarization) attraction at large distances, the two atoms repel one another. 1965P. Caws Philos. of Sci. xxii. 166 The gas law..is hopelessly inadequate in most cases, and has to be replaced by Van der Waals' equation..which is itself only approximately valid. 1979Sci. Amer. Dec. 145/1 If the sauce is kept cool, the colloidal particles are unlikely to touch one another with a frequency that would allow the van der Waals forces to make them coalesce into pools of butter. |