通过测量一束头发上较重的氢和氧同位素的比例，科学家可以构建一个地理时间轴。
By measuring the proportion of heavier hydrogen and oxygen isotopes along a strand of hair, scientists can construct a geographic timeline.
她经常把装有放射性同位素的试管放在口袋里，对试管里发出的漂亮的蓝绿光赞不绝口。
She had often carried test tubes containing radioactive isotopes in her pocket, remarking on the pretty blue-green light they gave off.
随着大量的水通过蒸发被抽离，并以雪的形式沉淀形成冰川冰，海洋中氧同位素的比率就发生了变化。
The oxygen isotope ratio of the ocean changes as a great deal of water is withdrawn from it by evaporation and is precipitated as snow to form glacial ice.
但是同位素的用处更多。
这项技术基于对同位素的研究。
这项技术依赖于对同位素的研究。
元素后面的数字表明特定同位素的身份。
The number after the element name identifies the specific isotope.
地球上没有稳定同位素的最轻的物质是什么？
What is the lightest element on Earth, with no stable isotope?
夏普和他的同事对此过程中两种氯同位素的情形进行了研究。
Sharp and his colleagues studied what happened to two isotopes of the element chlorine during that process.
经过了上千年，这两种碳同位素的比例一直是不变的。
For thousands of years, the ratio between the two has been the same.
但是研究团队发现在月球上氯的同位素的比率大约是地球上的25倍。
But the team found that on the Moon it was about 25 times that of the terrestrial chlorine isotope ratio.
它们晶体里重轻同位素的比例并不像是从地底挖出来的东西那样。
The ratio between the heavy and light isotopes of the element in their crystals is not quite right for stuff that has come out of the ground.
除了比对氧同位素的季度变化之外，渡边刚及其同事们还比对了年度的变化。
Besides finding season-to-season variations in oxygen isotopes, Watanabe and his colleagues discerned year-to-year variations.
这些同位素的比例能够告诉我们这些鸟的饮食状况，也就提供了它们的地域信息。
The isotope ratios tell you about the bird's diet. And that tells you where they dined.
地质学家在石笋上钻孔，使用铀衰变成钍的同位素的方法确定它们的年龄。
In this case the geologists drilled into the stalagmites and estimated their age from the way that uranium decays into an isotope of thorium.
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。
Taking stable iodine as a pill blocks the uptake of the hazardous radioisotope, which has a half-life of 8 days.
因此，如果对超对称性确信无疑，那么宇宙空间中元素同位素的存在就会比标准模式预测的要少。
So if supersymmetry is true, there should be less of this isotope around than the Standard Model predicts.
但是空气中的氮气中的氮原子却会被一个叫做同位素的有着不同数量中子的氮原子所替换。
But the nitrogen in the air was replaced with a nitrogen atom with a different number of neutrons, called an isotope.
从理论上讲，由此产生的搅动可以缓解识别这种宝贵同位素的负担并且有助于提取这种同位素。
In theory, the resulting agitation would ease identification of the precious isotope and aid its extraction.
他们的预测是基于积聚在地壳的罕见同位素的水平，轻微的太阳风使宇宙射线穿透地球的大气层。
Their prediction is based on levels of rare isotopes that accumulate in the Earth's crust when weak solar winds allow cosmic rays to penetrate the Earth's atmosphere.
今年3月，通过对冰岛一带贝壳的研究发现，其硬壳氧同位素的水平会随水温的变化而产生差异。
A study this March of clamshells taken from Iceland found that the levels of oxygen isotopes in the shell layers varied depending on the temperature of the water in which they formed.
并且，他们或许要对2号反应堆周边其他放射性同位素的含量，包括对铯、钡、钴、镧的浑浊度，进行重新检测。
And they still may need to retest for other radioactive isotopes that had been found in the seawater around the No. 2 reactor, including troubling quantities of cesium, barium, cobalt and lanthanum.
树木年轮的碳同位素和冰核中钚同位素的检测都显示出在上述阶段的大多数时间内太阳辐射能量出现下降。
Isotopes of carbon in tree rings and beryllium in ice cores show a drop-off in solar radiation during much of the period.
他们然后使用当地的降雪记录来寻找有气象记录的年代里降雪量和树木年轮中氧元素同位素的比率之间的关系。
They then used local snowfall records to find the relationship between precipitation and the proportion of heavy oxygen in tree rings for the years covered by the weather records.
他们对研发成功可使用的核弹并建造自己的反应堆感到自豪，尽管之后的制裁阻止他们输入技术并出席讨论同位素的会议。
They are proud of having developed a workable bomb and built their own reactors, despite sanctions that prevented them from importing technology or from attending conferences to discuss isotopes.
当研究者核对已经出版的同位素的数据时，他们发现查到的值和测量到的衰变速率不一致，而这个速率被物理学家假定是一个物理常量。
As the researchers pored through published data on specific isotopes, they found disagreement in the measured decay rates - odd for supposed physical constants.
本期《经济学人》付印之前，伊朗是否接受或讨价还价这项片面协议交易尚不明朗，该协议将使制造医学上同位素的一座研究反应炉维持运转。
As the Economist went to press it was unclear whether Iran would accept or haggle over the deal, which would keep in operation a research reactor that makes medical isotopes.
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.
“但是，多年来对地球化学的观察让我知道谨慎是明智的，”他说，“无论是这次对于氯同位素的研究还是早期对于水的研究都需要谨慎。”
"But years of observation of geochemistry have taught me that caution is wise," he says, "whether it be for the earlier claims on water or this latest work on chlorine isotopes."
因此，通过测量树的不同年轮(ring)中两种氧同位素的比例，并将结果比对年轮所显示的树龄，就可再现树木一生中所经历的所有飓风。
So, by measuring the ratio of the two isotopes in the rings of trees, and matching the result to the age of the ring, a history of hurricanes spanning the life of the tree can be reconstructed.
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