decay — [dē kā′, dikā′] vi. [ME decaien < Anglo Fr & OFr decäir < VL * decadere: see DECADENCE] 1. to lose strength, soundness, health, beauty, prosperity, etc. gradually; waste away; deteriorate 2. to rot or decompose 3. to undergo radioactive… … English World dictionary
decay — 1. Destruction of an organic substance by slow combustion or gradual oxidation. 2. SYN: putrefaction. 3. To deteriorate; to undergo slow combustion or putrefaction. 4. In dentistry, caries. 5. In psychology, loss of informat … Medical dictionary
decay — I. verb Etymology: Middle English, from Anglo French decaïr, from Late Latin decadere to fall, sink, from Latin de + cadere to fall more at chance Date: 15th century intransitive verb 1. to decline from a sound or prosperous condition 2. to… … New Collegiate Dictionary
Exponential decay — A quantity undergoing exponential decay. Larger decay constants make the quantity vanish much more rapidly. This plot shows decay for decay constants of 25, 5, 1, 1/5, and 1/25 for x from 0 to 5. A quantity is said to be subject to exponential… … Wikipedia
Proton decay — In particle physics, proton decay is a hypothetical form of radioactive decay in which the proton decays into lighter subatomic particles, usually a neutral pion and a positron. Proton decay has not been observed. There is currently no evidence… … Wikipedia
beta decay — Physics. a radioactive process in which a beta particle is emitted from the nucleus of an atom, raising the atomic number of the atom by one if the particle is negatively charged, lowering it by one if positively charged. [1930 35] * * * Any of… … 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
radiation measurement — ▪ technology Introduction technique for detecting the intensity and characteristics of ionizing radiation, such as alpha, beta, and gamma rays or neutrons, for the purpose of measurement. The term ionizing radiation refers to those… … Universalium
radiation — radiational, adj. /ray dee ay sheuhn/, n. 1. Physics. a. the process in which energy is emitted as particles or waves. b. the complete process in which energy is emitted by one body, transmitted through an intervening medium or space, and… … 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 — 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
