関連する実験動画

Updated: Jul 11, 2026

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations
10:11

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

Published on: August 3, 2016

ドレイク通路の水中のネオジミウムの同位体成分

D J Piepgras, G J Wasserburg

    Science (New York, N.Y.)
    |July 16, 1982
    PubMed
    まとめ

    ドレイク海峡の海水におけるネオジムイソトープは,南極環極流が70%大西洋の水であることを明らかにする. この発見は,海洋の混合を理解し,水の交換率を計算するのに役立ちます.

    さらに関連する動画

    Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod06:06

    Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod

    Published on: August 17, 2016

    The Floating Lab: Standard Operational Procedure for Collecting and Filtering Seawater Samples from Operating Ferries for Environmental DNA Analysis06:22

    The Floating Lab: Standard Operational Procedure for Collecting and Filtering Seawater Samples from Operating Ferries for Environmental DNA Analysis

    Published on: August 1, 2025

    関連する概念動画

    ¹H NMR of Labile Protons: Deuterium (²H) Substitution00:48

    ¹H NMR of Labile Protons: Deuterium (²H) Substitution

    This lesson illustrates the role of deuterium substitution in simplifying the NMR spectrum of compounds comprising labile protons. One method employed is the use of deuterium. Amongst the three isotopes of hydrogen, deuterium (2H) has a nucleus composed of one proton and one neutron. When the D2O solvent is added to a pure dry ethanol solution, its labile proton is substituted with deuterium.
    Atomic Nuclei: Nuclear Spin State Population Distribution01:14

    Atomic Nuclei: Nuclear Spin State Population Distribution

    Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
    Atomic Nuclei: Larmor Precession Frequency01:11

    Atomic Nuclei: Larmor Precession Frequency

    The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
    Diamagnetic Shielding of Nuclei: Local Diamagnetic Current01:14

    Diamagnetic Shielding of Nuclei: Local Diamagnetic Current

    An applied magnetic field causes the electrons present in the molecule to circulate, setting up a local diamagnetic current within the molecule. The local diamagnetic current arising from circulating sigma-bonding electrons induces a magnetic field, Blocal that opposes the applied magnetic field, B0. The effective magnetic field experienced by these nuclei is given by the difference between the applied and local magnetic fields in a phenomenon called local diamagnetic shielding. Essentially,...
    ¹³C NMR: ¹H–¹³C Decoupling01:04

    ¹³C NMR: ¹H–¹³C Decoupling

    The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
    A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
    Other Nuclides: 31P, 19F, 15N NMR01:16

    Other Nuclides: 31P, 19F, 15N NMR

    Many organic, inorganic, and biological molecules contain spin-half nuclei such as nitrogen-15, fluorine-19, and phosphorus-31. As a result, NMR studies of these nuclei have found extensive applications in chemical and biological research.
    While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...