Geological dates are usually obtained by using the rates of decay of various radioactive elements found in minerals.
地质年代通常是通过矿物中发现的各种放射性元素的衰变率来获得的。
Geological dates are usually obtained by using the rates of decay of various radioactive elements found in minerals.
地质年代通常是通过矿物中发现的各种放射性元素的衰变率来获得的。
These minerals can be dated by radioactive decay techniques because of the very small quantities of radioactive trace elements they, in turn, contain.
这些矿物可以用放射性衰变技术测定年代，因为它们所含的放射性微量元素非常少。
Helium is the by product of millennia of radioactive decay from the elements thorium and uranium.
氦是钍和铀元素数千年放射性衰变的副产品。
The radioactive displacement law of Fajans and Soddy was formulated to describe the products of alpha and beta decay.
法扬斯和索迪的放射性位移定律被用来描述α和β衰变的产物。
Once the reactor has shut down, there remains "decay heat" from traces of other radioactive isotopes.
一旦反应堆关闭，它仍热存在有来自其他放射性同位素踪迹的衰变热。
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。
Only gravity and a phenomenon called the weak nuclear force, which governs some types of radioactive decay, can bind them—hence the term “weakly interacting”.
只有重力和一种可以支配某些放射性衰变的弱核力能够使其聚集凝固，“弱反应”这一术语由此得名。
But rather than test the radioactive decay using just one method, the researchers used three, involving the elements lead, samarium and neodymium.
但是，相对于仅使用一个方法测试放射性衰变，研究人员测定时使用了三种元素，铅，钐，钕。
As radon progeny decay, they emit radioactive alpha particles and attach to aerosols, dust and other particles in the air.
氡子核在衰变时发射出放射性阿尔法粒子，这些粒子可附着于空气中的浮质、灰尘及其它粒子。
His advice to Purdue: Look for evidence that the changes in radioactive decay on Earth vary with the rotation of the sun.
他向普渡大学的研究者提出建议：寻找地球上放射性元素衰变速率的变化同太阳自转的关系。
The core of this model is a function called a stretched exponential relaxation, which is similar to the decay curve of a radioactive material.
这个模型的核心是延伸型指数函数的松弛效应，就像放射性物质的衰变曲线一样。
No one knows how neutrinos could interact with radioactive materials to change their rate of decay.
没人知道中微子中微子是如何同放射性材料发生作用并改变他们的衰变速率的。
Alpha particles are these helium nuclei, and they are the result of radioactive decay.
阿尔法粒子是氦核，它们是放射性衰变的产物。
Inlarge parts of the ocean, the seafloor is made of thick, heavy clay, perfectfor absorbing radioactive decay products.
在海洋的大部分区域，海床都由厚重的粘土构成，最适合吸收放射性衰变产物。
A lump of radioactive cesium-137, for example, may decay at a steady rate overall, but individual atoms within the lump will decay in an unpredictable, random pattern.
一团放射性铯137，整体以恒定的速率衰变，但是其内部单个原子的衰变是一种不可预测的随机模式。
Quantum tunneling is involved in many physical processes, such as radioactive decay and the nuclear fusion that takes place in the Sun.
量子隧穿发生在许多的物理过程中，比如说放射性衰变和太阳上发生的核聚变。
RTGs power many space missions — including NASA's Cassini and New Horizons probes — as the slow decay of small pellets of radioactive material produces heat that can be turned into electricity.
RTG已为许多太空任务提供动力，包括美国宇航局的“卡西尼号”和“新视野”探测器。在放射性物质的小球衰退过程中可以产生出热量，从而将其转化为电能。
The process by which an atom changes from an unstable state to a more stable state by emitting radiation is called radioactive decay or radioactivity.
原子通过辐射由不稳定状态转变为更加稳定状态的过程称为放射性衰变或放射性。
What helium is available is depleted in helium-3 relative to what we see in the sun, because most of Earth's helium-4 is freshly made via natural radioactive decay of the elements uranium and thorium.
当氦衰变成为氦-3相对于我们在太阳里看到的那它就可用了，因为地球上多数的氦-4是通过元素铀和钍自然放射性衰变而造成的。
Heat from the decay of naturally occurring radioactive elements could keep a planet warm enough for water.
放射性元素在自然衰败过程中所产生的热量能使星球上的水维持液态形式。
The ash contains minerals such as zircon that can be dated precisely from the radioactive decay of some of their components.
这些火山灰中含有锆石等矿物，这些矿物中的某些组分允许进行精确的放射性测年(以确定精确的年代数据)。
At an intermediate scale, however, they areoccasionally amplified to become observable, for example when wemeasure radioactive decay.
在中间尺度上，量子效应偶尔会被放大以致可被观察到，例如我们在测量放射性衰变的时候。
During a PET scan, the patient is injected with radioactive tracer molecules that emit positrons when they decay.
正电子断层扫描仪进行人体扫描的时候，病人被注入正电子放射性核素，然后推入检测环。
Ephraim Fischbach, a physics professor at Purdue, was looking into the rate of radioactive decay of several isotopes as a possible source of random numbers generated without any human input.
普渡大学物理教授EphraimFischbach，将探测几种同位素的放射性衰变速率的方法作为一种没有人为输入因素干扰的产生随机数的可能方法。
For instance, because it takes only 8 days for the radioactive isotope iodine-131 to decay away to half its original level of radioactivity, simply waiting should be a fix.
例如，碘- 131的放射性只需要八天就衰减到它原来的一半，所以只需要等一等问题就能解决。
The positrons, produced by the decay of radioactive sodium, are cooled into a similarly sized cloud of around 1m particles and held in a neighbouring trap.
由放射性钠衰变产生正电子，冷却后形成一个由大约100万个正电子组成的体积同样大小的粒子云团，这团正电子被存放在相邻的一个容器中。
The positrons, produced by the decay of radioactive sodium, are cooled into a similarly sized cloud of around 1m particles and held in a neighbouring trap.
由放射性钠衰变产生正电子，冷却后形成一个由大约100万个正电子组成的体积同样大小的粒子云团，这团正电子被存放在相邻的一个容器中。
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