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。

Thus, more of the heavy isotope is left behind in the ocean and absorbed by marine organisms.

因此，更多的重氧同位素留在了海洋里，并被海洋有机物吸收。

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The oxygen isotope ratio of the ocean changes as a great deal of water is withdrawn from it by evaporation and is precipitated as snow to form glacial ice.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。

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。

In 1931, at Columbia University, Harold Yuri discovered this isotope, which has two.

931年在哥伦比亚大学，哈罗德·尤里发现同位素，有两个核电荷数。

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。

The isotope-labeled chemical is used for the researchers to track its fate in the human body.

研究人员使用这种同位素追踪人体中的轨迹。

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。

So if supersymmetry is true, there should be less of this isotope around than the Standard Model predicts.

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。

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。

In theory, the resulting agitation would ease identification of the precious isotope and aid its extraction.

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。

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 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。

To make fuel for electricity-generating reactors, uranium is enriched to less than 5 percent of the isotope U-235.

为将燃料做成电能反应堆，铀被浓缩至U-235同位素含量5%以下。

But the nitrogen in the air was replaced with a nitrogen atom with a different number of neutrons, called an isotope.

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。

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。

This is the DEUT ERIUM PLANT, an automated facility for extracting the heavy isotope of hydrogen from the local water supply.

实际上这是个加工厂一个全自动化的设施通过来从当地水源中提取氢气的重同位素来生产氘气。

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。

And the heavier oxygen from a natural process that left more of the light isotope in the part of the nebula that made the sun.

重量较大的氧来自某种自然过程，在此过程中，大部分的轻同位素留在了形成太阳的部分星云中。