Fr.: disque circumnucléaire
A thick disk of gas and dust clouds surrounding the → Galactic Center up to about 20 → light-years. The disk is very clumpy; the → clumps have densities of several 105 particles/cm3, radii of about 0.3 light-years, and gas temperatures above 100 K. The hydrogen mass of the disk is a few 104 → solar masses. Such circumnuclear disks are present also in other galaxies.
1) Free from darkness, obscurity, or cloudiness.
M.E. clere, from O.Fr. cler, from L. clarus "clear, bright, distinct."
Runé, from Kurd. (Sorani) rûn "bright, clear," rûn kirdin "to explain," variant of rowšan, → bright.
Fr.: nuit claire
A night sky without clouds, mist, or haze, atmospheric dust particles, and without city lights in which a sixth magnitude star is visible by naked-eye.
Fr.: molécule homonucléaire
low-ionization nuclear emission-line region
nâhiye-ye hasteyi bâ xatt-e gosili-ye kamyoneš (#)
Fr.: Noyau de galaxie à raies d'émission de faible ionisation
Same as → LINER.
Of or pertaining to a → nucleus.
Haste-yi, from hasté, → nucleus, + -i adjective-forming suffix.
varqe-ye haste-yi (#)
Fr.: barrière nucléaire
The region of high potential energy through which a charged particle must pass on entering or leaving an atomic nucleus. → Gamow barrier.
Fr.: combustion nucléaire
A → nuclear reaction inside a star that produces the energy to make the star shine and also transform chemical elements into others.
bâr-e haste-yi (#)
Fr.: charge nucléaire
The positive electric charge on the nucleus of an atom.
Fr.: combustion nucléaire
Fr.: section efficace nucléaire
Apparent cross-section possessed by an atomic nucleus when it undergoes a particular type of collision process.
cagâli-ye haste-yi (#)
Fr.: densité nucléaire
The density of an atomic nucleus (about 1014 g/cm3).
Fr.: énergie nucléaire
Energy released during a nuclear reaction as the result of the conversion of mass into energy. → mass-energy equivalence.
šekâft-e haste-yi (#)
Fr.: fission nucléaire
A → nuclear reaction in which a heavy atomic nucleus splits into two or more approximately equal parts, usually as the result of the capture of a slow, or → thermal neutron by the nucleus. It is normally accompanied by the emission of further neutrons or → gamma rays and very large amounts of energy. The neutrons can continue the process as a → chain reaction, so that it becomes the source of energy in a → nuclear reactor or an atomic bomb. It may also be a trigger for → nuclear fusion in a hydrogen bomb. Fission occurs spontaneously in nuclei of uranium-235, the main fuel used in nuclear reactors.
niru-ye haste-yi (#)
Fr.: force nucléaire
The attractive force which acts between nucleons when they are extremely close together (closer than 10-13 cm).
suxt-e haste-yi (#)
Fr.: combustible nucléaire
A substance, such as uranium-238 or plutonium-239, which undergoes nuclear fission in a nuclear reactor.
Fr.: fusion nucléaire
A → nuclear reaction between atomic nuclei as a result of which a heavier → atomic nucleus is formed, a small fraction of mass is lost, and a large quantity of energy is released. Nuclear fusion is the source of the energy of stars.
nuclear magnetic resonance (NMR)
bâzâvâyi-ye meqnâtisi-ye haste-yi
Fr.: résonance magnétique nucléaire
An analysis technique applied to some atomic nuclei that have the property to behave as small magnets and respond to the application of a magnetic field by absorbing or emitting electromagnetic radiation. When nuclei which have a magnetic moment (such as 1H, 13C, 29Si, or 31P) are submitted to a constant magnetic field and at the same time to a radio-frequency alternating magnetic field, the nuclear magnetic moment is excited to higher energy states if the alternating field has the specific resonance frequency. This technique is especially used in spectroscopic studies of molecular structure and in particular provides valuable information in medicine that can be used to deduce the structure of organic compounds.
meqnâtis-e haste-yi (#)
Fr.: magnétisme nucléaire
The magnetism associated with the magnetic field generated by atomic nuclei.