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。

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

测量太阳的元素丰度时，看到大约有75%的氢、25%的氦。

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

现在要加上碳 13 丰度，这条金线。

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

对于核武器而言，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%。

This new method, the probability of fire, having the memory of the fuel abundance in their formulation allowed to really identify those regions that could be much more affected compared to simpler methods that only consider weather.

这种新方法通过在其算法中纳入燃料（植被）丰度的记忆功能，能够仅考虑天气因素的简单方法更准确地识别出那些可能受到更大影响的区域。

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种蚊科动物，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》。

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，可以告诉你，那些雄伟非凡的，如这一棵，实际上其构成成分中，有多达85%都是来自鲑鱼。

Meanwhile the changing chemistry of the oceans lowers the abundance of carbonate ions, making it harder for corals to form their skeletons.

同时，海洋化学物质的变化降低了碳酸盐离子的丰度，使得珊瑚更难形成骨骼。

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%。

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。

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核武器所需的丰度。

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

该核条约允许伊朗浓缩铀丰度限制在3.67%。

In this case, high-assay low-enriched uranium.

在这种情况下，是高浓缩低丰度铀。

[Derek] They thaw out the old generation, mix it into a flask with the current generation, and then plate out a sample of the solution to see the relative abundances of the two populations at the start.

[Derek] 他将老一代解冻，将其与前一代混合到烧瓶中，然后取出溶液样本， 以查看开始时两个种群的相对丰度。

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.

大爆炸模型预测了元素的丰度——元素与氢的值——这正是在整个宇宙中所看到的。

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

但是到了 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。

So we're monitoring periodically the abundance and the diversity of the rivers.

因此，定期监测河流的丰度和多样性。

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

发现在马拉松赛后，它在肠道中的丰度明显更高。

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

所以，在这一点上， 元素丰度被锁定了。