然而，大约在同一时间，科学家们意识到彗星可能含有衰变的放射性同位素，这些同位素可能使彗星内部的温度升高到导致内部进化的温度。
About the same time, though, scientists realized comets might contain decaying radioactive isotopes that could have warmed cometary interiors to temperatures that caused the interiors to evolve.
这么大的原子核不可能是稳定的，但在足够长的时间内，在真空附近组装一个原子核以观察真空的衰变是可能的。
A nucleus that large cannot be stable, but it might be possible to assemble one next to a vacuum for long enough to observe the decay of the vacuum.
食品中的放射性碘直接引起人们的关注，但是它的半衰期相对较短并将在短时间内自然衰变。
Radioactive iodine in food is of immediate concern, but it has a relatively short half-life and will naturally decay over a short time frame.
随着时间推移，碳14将衰变为常规的碳12。
这个效应可以在时间域通过观测电压的衰变率来测量，也可以在频率域通过正弦电流和电压之间的相变来测量。
This effect can be measured in either the time domain by observing the rate of decay of voltage or in the frequency domain by measuring phase shifts between sinusoidal currents and voltages.
又如，某种放射性物质可能正在以已知的速度进行衰变，需要我们确定在给定的时间后遗留物质的总量。
Or a radioactive substance may be disintegrating at a known rate and we may be required to determine the amount of material present after a given time.
为先驱者号们提供舱内热动力源的钚238会有放射性衰变，其发射量会随着时间的推移而越来越小。
As the plutonium-238 that served as the Pioneers' onboard heat source radioactively decayed, it would have emitted less heat over time.
这里所指的半衰期是现存原子的一半发生衰变或爆炸所消耗的时间。
By that is meant the time which elapses before half of the existing atoms have disintegrated or exploded.
在过去一个世纪中，物理学家们透过全面的观察与实验，证明碳-14原子要花费5,730年的时间来衰变为一个稳定的氮- 14原子。
Physicists have proven through exhaustive observation and experimentation over the course of a century that it takes 5,730 years for Carbon-14 atoms to decay into a stable Nitrogen-14.
同位素铀衰变通过阿尔法和贝塔过程中，类似的时间尺度这一核心。
The isotope 212bi decays through both alpha and beta processes that have similar time-scales for this nucleus.
系统的响应时间是毫微秒量级的，测量得到的衰变曲线是溶液的真实衰变曲线与仪器响应函数卷积的结果。
The response time of the system was in the order of nanoseconds. The observed fluorescence decay curves were convolutional results of the real decay curves and the instrumental response curve.
因为它们有着与光速非常接近的速度，所以它们的衰变时间是实验室里静止的介子衰变时间的30倍。
Because they had a speed close to that of light, they took thirty times longer to disintegrate than muons that just sit still in the laboratory.
因为它们有着与光速非常接近的速度，所以它们的衰变时间是实验室里静止的介子衰变时间的30倍。
Because they had a speed close to that of light, they took thirty times longer to disintegrate than muons that just sit still in the laboratory.
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