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half-life

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half-life

Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++
Related topics: Physics
ˈhalf-life noun [countable]  HPthe length of time it takes a radioactive substance to lose half of its radioactivity 〔放射性物质的〕半衰期
Examples from the Corpus
half-lifeThe time it takes for a dose of a drug to wear off is measured by a value called a half-life.But it has a half-life of just 140 days so there can be little delay manufacture and its incorporation into a bomb.With a half-life of 12 years, tritium could build up in the Tamar estuary and eventually enter the human food chain.The more complete descriptive term is drug elimination half-life.The time taken for half of the atoms of a radioactive isotope to decay is called its half-life.No one has a long half-life as the star of the program.These effects are less marked with fentanyl because of its shorter serum half-life.The daily intake should be divided into at least three doses because of the short half-life.
ˈhalf-life nounChineseSyllable
Corpus time the to length of substance it lose takes a radioactive


half-life
ˈhalf-life noun [countable]
the length of time it takes a radioactive substance to lose half of its radioactivity


half-lifeBrE /ˈhɑːf laɪf/ 🔊NAmE /ˈhæf laɪf/ 🔊 noun [countable] (physics 物理) the time taken for the radioactivity of a substance to fall to half its original value (放射性物质的)半衰期the time taken for the concentration of a substance in the body to fall to half its original value (体内物质的)半衰期