The → attractive force that holds together neighboring → atoms in → molecules.
Bond, variant of band, from M.E. bende, O.E. bend, from O.Fr. bande, bende, PIE *bendh- "to bind" (cf. Goth bandi "that which binds;" Av./O.Pers. band- "to bind, fetter," banda- "band, tie" (see below); Skt. bandh- "to bind, tie, fasten," bandhah "a tying, bandage").
Band "band, tie," from Mid.Pers., O.Pers./Av. band- "to bind," banda- "band, tie," also present stem of bastan "to bind, shut," → shutter.
Fr.: albedo de Bond
The fraction of the total amount of electromagnetic radiation falling upon a non-luminous spherical body that is reflected in all directions by that body. The bond albedo takes into account all wavelengths at all → phase angles. Compare with → geometric albedo.
Named after the American astronomer George Phillips Bond (1825-1865), who proposed it; → albedo.
Fr.: accrétion de Bondi-Hoyle
The → accretion of mass by a star (assumed as point particle) moving at a steady speed through an infinite, uniform gas cloud. It is directly proportional to the star mass (M) and the medium density (ρ) and inversely proportional to the relative star/gas velocity (v). In its classical expression: 4πρ(G M)2 / v3, where G is the → gravitational constant. See Bondi & Hoyle (1944, MNRAS 104, 273) and Bondi (1952, MNRAS 112, 195). For a recent treatment of accretion in a turbulent medium see Krumholtz et al. 2006 (ApJ 638, 369).
Named after Hermann Bondi (1919-2005), an Anglo-Austrian mathematician and cosmologist and Fred Hoyle (1915-2001), British mathematician and astronomer best known as the foremost proponent and defender of the steady-state theory of the universe; → accretion.
Bondi-Hoyle accretion radius
šo'â'-e farbâl-e Bondi-Hoyle
Fr.: rayon de l'accrétion de Bondi-Hoyle
In the → Bondi-Hoyle accretion process, the radius where the gravitational energy owing to star is larger than the kinetic energy and, therefore, at which material is bound to star. The Bondi-Hoyle accretion radius is given by RBH = 2 GM / (v2 + cs2) where G is the gravitational constant, M is the stellar mass, v the gas/star relative velocity, and cs is the sound speed.
→ Bondi-Hoyle accretion; → radius.
band-e šimik, ~ šimiyâyi
Fr.: liaison chimique
A force by which chemical substances are held together by attraction of atoms to each other through sharing, as well as exchanging, of electrons.
Fr.: lien covalent
A chemical bond between two atoms of the same or different elements, in which each atom contributes one electron to be shared in a pair.
Fr.: liaison hydrogène
The attractive force between the hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule. Usually the electronegative atom is oxygen, nitrogen, or fluorine, which has a partial negative charge. The hydrogen then has the partial positive charge.
Fr.: lien polaire
A chemical bond where the electrons are shared unequally between atoms. The atom that is more electronegative will pull the electrons closer to itself.