spontaneous nucleus

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• Spontaneous fission — (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 u (elements near ruthenium). In practice, however, spontaneous fission is… …   Wikipedia

• Spontaneous emission — is the process by which a light source such as an atom, molecule, nanocrystal or nucleus in an excited state undergoes a transition to the ground state and emits a photon. Spontaneous emission of light or luminescence is a fundamental process… …   Wikipedia

• spontaneous fission — ▪ physics       type of radioactive decay in which certain unstable nuclei of heavier elements split into two nearly equal fragments (nuclei of lighter elements) and liberate a large amount of energy. Spontaneous fission, discovered (1941) by the …   Universalium

• Dentate nucleus — This article is about the dentate nucleus. For other dentate, see Dentate. Brain: Dentate nucleus Sagittal section through right cerebellar hemisphere. The right olive has also been cut sagitally. (Dentate nucleus labeled at top.) Latin nucleus… …   Wikipedia

• Subthalamic nucleus — Brain: Subthalamic nucleus Coronal slices of human brain showing the basal ganglia, subthalamic nucleus (STN) and substantia nigra (SN) …   Wikipedia

• Dorsal cochlear nucleus — Brain: Dorsal cochlear nucleus Dorsal cochlear nucleus is #4, at upper left …   Wikipedia

• Medullary command nucleus — The medullary command nucleus (MCN), also called the pacemaker nucleus, is a group of nerve cells found in the bodies of weakly electric fish. It controls the function of electrocytes by regulating the frequency of electrical impulses. Signals… …   Wikipedia

• nuclear fission — fission (def. 2). [1885 90] * * * Division of a heavy atomic nucleus into two fragments of roughly equal mass, accompanied by the release of a large amount of energy, the binding energy of the subatomic particles. The energy released in the… …   Universalium

• transuranium element — Any of the chemical elements after uranium in the periodic table (with atomic numbers greater than 92). All are radioactive (see radioactivity), with half lives ranging from tens of millions of years to fractions of a millisecond. Only two,… …   Universalium

• radioactivity — /ray dee oh ak tiv i tee/, n. Physics, Chem. the phenomenon, exhibited by and being a property of certain elements, of spontaneously emitting radiation resulting from changes in the nuclei of atoms of the element. Also called activity. [1895… …   Universalium

• Nuclear fission — For the generation of electrical power by fission, see Nuclear power. Splitting the atom redirects here. For the EP, see Splitting the Atom. Nuclear physics Radioactive decay Nuclear fission Nuclear fusio …   Wikipedia