我们现在的氦源，是地下天然气田中放射元素衰变的副产品，经过数十亿年的累积，逐渐形成的。
Our modern supply of helium has gradually built up over billions of years in subterranean pockets of natural gas as a byproduct of decaying radioactive elements.
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。
Geological dates are usually obtained by using the rates of decay of various radioactive elements found in minerals.
氦是钍和铀元素数千年放射性衰变的副产品。
Helium is the by product of millennia of radioactive decay from the elements thorium and uranium.
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。
These minerals can be dated by radioactive decay techniques because of the very small quantities of radioactive trace elements they, in turn, contain.
日本的KamLAND探测器可以检测衰变的铀和钍产生的反中微子，这两种元素产生了地球放射热量中的很大部分。
The KamLAND detector in Japan can detect anti-neutrinos generated by the decay of uranium and thorium-the two elements responsible for most of the radioactive heating of the Earth.
这些物质被称作“放射性同位素”—同一种元素的变种，他们具有异常的中子数量，频繁的衰变和放出辐射。
These materials are known as "radioisotopes" -versions of an element that, because they have an abnormal number of neutrons, frequently decay and release radiation.
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。
But rather than test the radioactive decay using just one method, the researchers used three, involving the elements lead, samarium and neodymium.
行星科学家们可以通过计算一个特定元素有多少“母亲”放射性同位素衰变为“女儿”同位素来确定岩石的年龄。
Planetary scientists can determine a rock's age by calculating how many radioactive "parent" isotopes of a particular element have decayed into "daughter" isotopes.
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。
His advice to Purdue: Look for evidence that the changes in radioactive decay on Earth vary with the rotation of the sun.
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。
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.
这种超重元素通常是具有非常强的放射性，并且几乎立即会发生衰变。
Such superheavy elements are usually very radioactive and decay away almost instantly.
这四种新元素都是人造的，是由火花与原子核相互撞击并且循着放射性超重元素衰变的轨迹而发现的。
The four new elements, all of which are synthetic, were discovered by slamming lighter -nuclei into each other and tracking the following decay of the radioactive superheavy elements.
已将其用于实践的目的，去鉴别元素和阐明放射性衰变系。
It had been used for practical ends, to identify elements and to unravel radioactive decay chains.
水温来源于地热增温率及放射元素的衰变产生热能。
The water temperature originates in geothermy warming rate and the radioactive element decay has the heat energy.
每个元素至少有一个同位素不稳定原子核可以进行放射性衰变。
Each element has at least one isotope with unstable nuclei that can undergo radioactive decay.
放射性同位素，是指某种发生放射性衰变的元素中具有相同原子序数但质量不同的核素。
"Radioisotopes" refer to a certain type of elements producing radiation decay that have the same atomic number but different mass of nuclides.
根据放射性元素分布规律、地质背景及放射性元素衰变等，建立了计算氡析出率的理论公式。
On the basis of distribution of radioactive elements and geological background, the theory equation of radon exhalation rate is derived from the decay rule of radioactive elements and gas diffusion.
如同伽利略号，卡西尼号的能源来自放射性元素钸的自然衰变，产生热后再转换成电。
Like Galileo, Cassini is powered by the natural decay of the radioactive element plutonium, which generates heat that is then converted to electricity.
如同伽利略号，卡西尼号的能源来自放射性元素钸的自然衰变，产生热后再转换成电。
Like Galileo, Cassini is powered by the natural decay of the radioactive element plutonium, which generates heat that is then converted to electricity.
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