As an indicator of shifts in the Earth's climate, the isotope record has two advantages.
作为地球气候变化的指标，同位素记录有两个优势。
Almost all the oxygen in water is oxygen 16, but a few molecules out of every thousand incorporate the heavier isotope 18.
水中几乎所有的氧都是氧16，但每一千个分子中就有几个含有较重的同位素18。
It is a global record: there is remarkably little variation in isotope ratios in sedimentary specimens taken from different continental locations.
这是一个全球性的记录：在取自不同大陆位置的沉积标本中，同位素比率的变化非常小。
The oxygen isotope ratio of the ocean changes as a great deal of water is withdrawn from it by evaporation and is precipitated as snow to form glacial ice.
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。
When the air was warm, vapor containing the heavier isotope, oxygen-18, condensed and formed precipitation, in the form of snow, more readily than did vapor containing oxygen-16.
当空气温度较高时，含有较重同位素氧-18的蒸汽比含有氧-16的蒸汽更容易凝结，并形成雪状的降水。
The dated isotope record shows that the fluctuations in global ice volume over the past several hundred thousand years have a pattern: an ice age occurs roughly once every 100,000 years.
同位素年代记录显示，过去几十万年全球冰量的波动有一个模式：冰河期大约每10万年发生一次。
And this again is the fissile isotope.
这也是易裂变同位素。
The isotope does occur in nature but only extremely rarely.
钋的同位素在自然界中的确存在，但是相当罕见。
This creates regions with geographically similar isotope values.
这将形成地理上同位素构成类似的区域。
The number after the element name identifies the specific isotope.
元素后面的数字表明特定同位素的身份。
What is the lightest element on Earth, with no stable isotope?
地球上没有稳定同位素的最轻的物质是什么？
The experiment involved irregular ion movement theory and isotope theory.
这项实验涉及了不规则离子运动理论和同位素理论。
The isotope ratios tell you about the bird's diet. And that tells you where they dined.
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。
It contains a tiny pellet of fuel made from an isotope of hydrogen called deuterium.
其中放置了一个更微小的氘(氢的一种同位素)燃料丸。
When the commonest isotope of iron (56Fe) absorbs a neutron, the result is not radioactive.
当最普通的铁（56Fe）的同位素吸收了一个中子，生成物无放射性。
But the team found that on the Moon it was about 25 times that of the terrestrial chlorine isotope ratio.
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。
What's more, it detected comparatively high levels of the isotope deuterium in Venus' upper atmosphere.
除此之外，探测器还在金星高层大气中检测到较高水平的氘。
The subsequent plankton bloom sucked up the 12c and the isotope ratio veered off in the opposite direction.
随之而来勃发的浮游生物吸走了12c，碳同位素比率转向相反方向。
It also bodes ill for the prospect of fusion using helium-3, a rare helium isotope that is missing a neutron.
这也预示着，利用氦- 3这种缺少一个中子的稀有的氦同位素进行核聚变的前景很黯淡。
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。
The composition of oxygen isotope is a good tool to trace the origin and formation environment of sulfate.
氧同位素组成是一个非常有效的示踪硫酸盐的起源和形成环境的工具。
Experts have played down the dangers, arguing that the isotope of nitrogen known as nitrogen-16 lasts for only five seconds.
专家们说相关辐射危险性很小，因为氮的同位素氮16只会存在5秒钟。
When we count up the lithium atoms held in stars, there is only one-third as much of the lithium-7 isotope as there should be.
当我们算出了在各个恒星中锂原子的总数，同位素锂- 7的总量仅是在那里应有量的三分之一。
These cancers can be prevented if children are given pills containing the non-radioactive isotope of iodine soon after exposure.
这些癌症其实是可以避免的，只要在受到辐射之后，马上给儿童们服用不具有放射性的碘的同位素做成的药片。
Calculations suggest, for instance, that in the nucleus of the isotope thorium-229 is a transition that should emit ultraviolet rays.
举例来说，计算表明，钍- 229的原子核内存在着能发出紫外线的转变过程。
In this case the geologists drilled into the stalagmites and estimated their age from the way that uranium decays into an isotope of thorium.
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。
The importation of the radioactive isotope, radiation equipment and other radioactive materials should come up to applicable state regulations.
进口放射性同位素、射线装置和含有放射性物质的物品的，按照国家有关规定办理。
It is made up of old fuel rods that have become sufficiently depleted of uranium-235, the isotope that drives a reactor’s main chain reaction, to be no longer useful.
乏燃料由完全耗尽铀-235的旧燃料棒组成，核反应堆的链式反应就是由铀-235激发的。
The krypton and xenon isotope ratios in the gas samples provided a surprising result: They did not match the ratios found in the primordial cloud that spawned the solar system.
气体采样中的氪和氙同位素比值产生了一个令人吃惊的结果：这些比值跟在形成太阳系的原始云团中所发现的比值不一致。
The krypton and xenon isotope ratios in the gas samples provided a surprising result: They did not match the ratios found in the primordial cloud that spawned the solar system.
气体采样中的氪和氙同位素比值产生了一个令人吃惊的结果：这些比值跟在形成太阳系的原始云团中所发现的比值不一致。
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