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half life

/ˈhɑːf ˌlaɪf/

翻译: 指某种量(如放射性物质、体内药物或化学反应物)减少到初始值一半所需的时间。也比喻事物随时间衰减或消亡的速度。

1 个条目

phrase

/ˈhɑːf ˌlaɪf/C1formalscientific
  • zh指某种量(如放射性物质、体内药物或化学反应物)减少到初始值一半所需的时间。也比喻事物随时间衰减或消亡的速度。

The time required for a quantity (such as a radioactive substance, a drug in the body, or a chemical reaction) to reduce to half its initial value. Also used metaphorically to describe the rate of decline or decay of something over time.

  1. Radioactive decayC1formal

    The time required for a quantity of a radioactive substance to reduce to half of its initial value.

    zh半衰期

    • The half-life of carbon-14 is about 5,730 years.
    • Scientists use half-life to date ancient artifacts.
    • Uranium-238 has a half-life of 4.5 billion years.
  2. Chemical eliminationC1formal

    The time it takes for the concentration of a substance (e.g., a drug) in the body to decrease by half.

    zh半衰期

    • The drug has a half-life of approximately 12 hours.
    • Doctors consider the half-life when prescribing medication.
    • The half-life of caffeine in the human body is about 5 hours.