Most people are not aware that caffeine has a half life of up to eight hours and can affect not only your ability to fall asleep, but also the quality of sleep you are getting.
大多数人都不知道，咖啡因有一个长达八小时的半衰期，不仅会影响你的入睡能力，而且还会影响你的睡眠质量。
Most famously, uranium-238 decays into lead-206 with a half life of 4.5 billion years, though radioactive rubidium and samarium are also useful for dating things billions of years old.
最为有名的就是铀- 238衰变为铅- 206的半衰期为45亿年，当然放射性铷和钐也同样对测算几十亿年前的物体的年龄很有用。
Objective:To study stability of stable chlorine dioxide, and predict its half life and term of validity.
目的：研究稳定态二氧化氯的稳定性能，并预测其半衰期及有效期。
The linear correlations between viscosity of bulk foaming solution and half life, reciprocal draining rate constant were experimentally examined.
本文以实验证实发泡液本体粘度与泡沫半衰期及与流失速率常数的倒数之间均存在线性关系。
Conclusions:Recovery half life of gas exchange in COPD is significantly longer than in the normal individuals and is not influenced by aminophylline in common dosage.
结论：COPD患者极量运动后气体交换参数恢复半衰期较正常人明显延长，常规剂量氨茶碱对此无明显影响。
The two film mass transfer model was used to estimate the volatilization coefficients and half life of the fourteen volatile organic chemicals(VOCs) detected in Dalian Bay.
本文采用气液双膜模型和大连湾水文参数，对大连湾检测出的挥发性有机物的挥发速率常数进行估算。
Better still, it became apparent to him that one could use radioactivity as a clock, with the half-life of a decay series enabling us to calculate the age of a rock.
更妙的是，显然人们可以用放射性作为时钟，用衰变系列的半衰期计算出岩石的年龄。
“The more we seek satisfactions in material goods, the less we find them there,” Ryan says. “The satisfaction has a short half-life -- it’s very fleeting.”
“越想在物质生活上寻找满足感，越难找到，”瑞安说：“这种满足感半衰期很短，很容易消失。”
The danger of nitrogen-16 is an issue only for plant workers and operators because its half-life is only seven seconds.
氮16的危险只针对于核电站工人和机器操作者而存在，因为它的半衰期只有七秒钟。
Iodine 131 has a half-life of eight days, meaning that every eight days it loses half its strength.
碘131有八天的半衰期，这意味着每八天其能量就下降一半。
So, the half-life is just the time that it takes for half of the reactants to disappear.
半衰期实际上是,一半反应物消失的时间。
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.
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。
It is often said that nuclear waste has a half-life of 100, 000 years…it is worth remembering that Stonehenge was built only 4, 000 years ago.
要知道，核废料的半衰期是100000年——而英 国的巨石阵仅有四千年的历史。
As with radioactivity, stories have a half-life-in other words a period by which half of newly promoted stories are relegated to a nether page.
与放射性一样，故事有一个半衰期-换言之，就是新推荐的故事从首页到被下放的周期。
Mutagenesis library is developed for identifying key residues of protein, raising the affinity, and prolonging half-life of protein.
蛋白突变库主要应用于提高蛋白亲和力、延长半衰期、确定蛋白关键残基。
The results showed that fomesafen disappeared rapidly in soil, and its half-life in Chuzhou was slightly longer than that in Hangzhou.
结果表明，其在土壤中降解消失较快，安徽试验点的半衰期比浙江试验点的略长。
The decay rate of the C-14 sample with its long half-life should be nearly constant during the short duration of the experiment.
在一个短实验周期里，具有较长半衰期的C 14样品的衰变速率应该是一个近似常数。
The half-life of some of the oral agents may be as long as 60 hours (chlorpropamide).
有些口服降糖药的半衰期可达到60小时（氯磺丙脲）。
The degradation dynamic, half-life and degradation factors of chlorpyrifos in vegetables, fruits and soils are summarized.
综述了毒死蜱在蔬菜、水果、土壤中的降解动态、半衰期以及影响药物降解因素等方面的研究现状。
Business opportunities have a half-life, just like uranium.
商业机会有半衰期，就像铀一样。
However, if the half-life is increased, the situation changes.
然而，如果半衰期增加，情况会改变。
Radioactive iodine has a half-life of eight days and decays naturally within weeks.
放射性碘的半衰期为八天，几周内自然衰变。
The city's challenge, chiefly, is to dispose of cesium-137, a radioactive isotope with a half-life of 30 years.
这座城市面临的最大问题就是处理铯—137，这是一种半衰期为30年的放射性同位素。
This radioactive element has a half-life of some 5, 700 years.
这种放射性元素半衰期约为5700年。
Cesium-137, with a half-life of 30 years, is another dangerous substance emitted in a full-scale nuclear meltdown.
核反应堆完全熔解后，会释放出另一种危险物质铯- 137。铯- 137的半衰期为30年。
It accumulates in the cooling water of nuclear reactors and is often vented in small amounts to the environment. Its half-life is 12 years.
氚聚集在核反应堆的冷却水中，通常以微量排放到环境中，其半衰期为12年。
Over the long term, the big threat to human health is cesium-137, which has a half-life of 30 years.
长期以来，对人体健康的一大威胁就是铯137，它的半衰期为三十年。
The developing thyroid gland absorbs iodine like a sponge; taking stable iodine as a pill blocks the uptake of the hazardous radioisotope, which has a half-life of 8 days.
处于发育阶段的甲状腺就如同海绵一般源源不断的吸收碘；服用稳定的碘元素会阻止危险碘同位素的摄入，碘同位素的半衰期仅为八天。
The developing thyroid gland absorbs iodine like a sponge; taking stable iodine as a pill blocks the uptake of the hazardous radioisotope, which has a half-life of 8 days.
处于发育阶段的甲状腺就如同海绵一般源源不断的吸收碘；服用稳定的碘元素会阻止危险碘同位素的摄入，碘同位素的半衰期仅为八天。
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