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Helium-4
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  • Helium-4 ( or ) is a non-radioactive isotope of the element helium. It is by far the most abundant of the two naturally occurring isotopes of helium, making up about 99.
  • 网络释义

    短语

    liquid helium 3-helium 4 mixture氦3氦4溶液

    helium 3-helium 4 mixture氦3氦4混合体

    Helium-3 and Helium-4 Mixtures

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