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algebraic number

(Encyclopedia)algebraic number: see number.

BCS theory

(Encyclopedia)BCS theory: see superconductivity. ...

tidal theory

(Encyclopedia)tidal theory: see solar system.

protoplanet theory

(Encyclopedia)protoplanet theory: see solar system. ...

encounter theory

(Encyclopedia)encounter theory, in astronomy, see solar system. ...

Avogadro's number

(Encyclopedia)Avogadro's number ävōgäˈdrō [key] [for Amedeo Avogadro], number of particles contained in one mole of any substance; it is equal to 602,252,000,000,000,000,000,000, or in scientific notation, 6.0...

atomic number

(Encyclopedia)atomic number, often represented by the symbol Z, the number of protons in the nucleus of an atom, as well as the number of electrons in the neutral atom. Atoms with the same atomic number make up a c...

octane number

(Encyclopedia)octane number, figure of merit representing the resistance of gasoline to premature detonation when exposed to heat and pressure in the combustion chamber of an internal-combustion engine. Such detona...

index number

(Encyclopedia)index number, in econometrics, a figure reflecting a change in value or quantity as compared with a standard or base. The base usually equals 100 and the index number is usually expressed as a percent...

Mach number

(Encyclopedia)Mach number mäk [key] [for E. Mach], ratio between the speed of an object and the speed of sound in the medium in which the object is traveling. An airplane that has the velocity of Mach 3.0 is trave...