However, it is far below the purity needed to make a nuclear weapon.

不过，这个丰度还远低于制造所需的丰度。

The pact had allowed Iran to enrich uranium at a 3.67 percent concentration level.

该条约允许伊朗浓缩铀丰度限制在3.67%。

Now we're gonna add in the carbon 13 abundance, this gold line.

现在我们要加上碳 13 丰度，这条金线。

In exchange, Iran will halt nuclear enrichment above five percent in purity.

而伊朗则要保证暂停生产丰度为5%以上的浓缩铀。

For such weapons, a purity level of about 90 percent is required.

对于而言，丰度要达到大概90%才行。

Iran began enriching uranium up to 60 percent in April.

伊朗从4月份开始将浓缩铀丰度提升至60%。

The United States gave 331 kilograms of weapons-grade plutonium to Japan during the Cold War.

美国曾于冷战时期给日本331公斤级丰度的钚。

When we measure the Sun's elemental abundance, we see it's roughly 75% hydrogen, 25% helium.

当我们测量太阳的元素丰度时，我们看到大约有75%的氢、25%的氦。

Researchers around the world use this type of tool to estimate population numbers and overall abundance of species.

全世界的研究者都用这种工具来估计种群数量和物种整体丰度。

But since mid-2019 after the U.S. withdrew from the pact, Iran has pushed enrichment levels back up to 20 percent.

但自2019年年中美国退出该条约后，伊朗已将浓缩铀丰度水平推高至20%。

So, at this point, the elemental abundances were locked in.

所以，在这一点上， 元素丰度被锁定。

We found it was very significantly higher in abundance in the gut after the marathon.

我们发现在马拉松比赛后，它在肠道中的丰度明显更高。

But then around 1850, right when carbon dioxide concentration started to rise, the carbon 13 abundance started taking a nosedive.

但是到 1850 年左右，就在二氧化碳浓度开始上升的时候，碳 13 的丰度开始急剧下降。

Its abundance can be calculated from its effects on visible matter—than which, the sums suggest, it is six times more plentiful.

它的丰度可以根据它对可见物质的影响来计算——总和表明，它的丰度是可见物质的六倍。

The Big Bang model predicts certain abundances of elements — ratios of them, compared to hydrogen — and that's just what we see in the Universe at large.

大爆炸模型预测元素的丰度——元素与氢的比值——这正是我们在整个宇宙中所看到的。

They collected data from 123 papers published over the past half-century that estimated parasite abundance in various species at sites all over the world between 1967 and 2017.

他们从过去半个世纪发表的 123 篇论文中收集数据，这些论文估计 1967 年至 2017 年间世界各地不同物种的寄生虫丰度。

And so what that means is by measuring the regions of those spectra, where we see less light, we can actually understand the element abundances, like oxygen, magnesium and silicon.

所以这意味着通过测量这些光谱的区域，我们看到较少的光，我们实际上可以解元素的丰度，比如氧、镁和硅。

By measuring the abundance of that nitrogen isotope in this material, I can tell you that majestic old giants like this beauty here are actually composed of up to 85% material that's derived from salmon.

通过测量这种原料中氮同位素的丰度，我可以告诉你，那些雄伟非凡的古树，比如这一棵，实际上其构成成分中，有多达85%都是来自鲑鱼。

Using a combination of camera traps, aerial imagery, and field observations, the researchers measured the density and abundance of tapir droppings in three different parts of the rainforest over the course of seven years.

研究人员结合使用相机陷阱、航拍图像和实地观察，在七年的时间里测量热带雨林三个不同部分的貘粪便密度和丰度。

It is home to 47 species of Culicidae, including two that were first recorded in the United States in Dr. Bajwa's 2018 study, " A Taxonomic Checklist and Relative Abundance of the Mosquitoes of New York City."

这里有47种蚊动物，其中两种在美国首次被记录于巴杰瓦博士2018年的研究论文《纽约市蚊子分类清单和相对丰度》。