Results 51 to 60 of about 105,676 (166)
atmospheric helium isotopic ratio
Geophysical Research Letters, 1993 A recent study of the isotopic ratio of helium (3He/4He) in the terrestrial atmosphere led the individuals who made the investigation to suggest that this ratio is decreasing with time, probably due to anthropogenic release of low isotopic ratio crustal helium from oil and gas wells. The measurements made over an 11 year period from 1977 to 1988 led to
John H. Hoffman, Alfred O. Nier
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Absolute Ca Isotopic Measurement Using an Improved Double Spike Technique
Terrestrial, Atmospheric and Oceanic Sciences, 2009 A new vector analytical method has been developed in order to obtain the true isotopic composition of the 42Ca-48Ca double spike. This is achieved by using two different sample-spike mixtures combined with the double spike and natural Ca data.
Jason Jiun-San Shen +2 more
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Nuclear Engineering and Technology, 2019 An experimental validation of a nuclear forensics methodology for the source reactor-type discrimination of separated weapons-useable plutonium is presented.
Jeremy M. Osborn +5 more
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Analysis of Hydrogen Isotope Abundance by High Resolution Isotope Ratio Mass Spectrometry
Zhipu XuebaoHigh resolution isotope ratio mass spectrometry (HR-IRMS) is often used to measure the abundance of deuterium to verify the efficiency of isotope isolation of a cryogenic distillation column system.
Chao WU +5 more
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Carbon Isotope Chemistry in Protoplanetary Disks: Effects of C/O Ratios
The Astrophysical JournalCarbon isotope fractionation of CO has been reported in the disk around TW Hya, where elemental carbon is more abundant than elemental oxygen ([C/O] _elem > 1).
Seokho Lee, Hideko Nomura, Kenji Furuya
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Journal of Ginseng Research, 2018 Background: The geographical origin of Panax ginseng Meyer, a valuable medicinal plant, is important to both ginseng producers and consumers in the context of economic profit and human health benefits.
Ill-Min Chung +8 more
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Citation: 'isotope ratio' in the IUPAC Compendium of Chemical Terminology, 5th ed.; International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.12452 • License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International for individual terms. Requests for
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Progress in Earth and Planetary ScienceWe determined the carbon and nitrogen isotope compositions of biologically important 21 amino acids and 7 nucleobases, which are used as working standards. These isotopic compositions were determined using a high-sensitivity elemental analyzer coupled to
Nanako O. Ogawa +4 more
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Oxygen Kinetic Isotope Effects in the Thermal Decomposition and Reduction of Ammonium Diuranate
ACS Omega, 2021 Michael R. Klosterman +5 more
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Isotope ratio - Mass spectrometry
, 2012 This article summarizes the configurations involving isotope ratio mass spectrometry (IRMS) technology available at the CCiTUB and the wide range of possible applications. Some examples of these applications are shown.
Marimon Corbella, Rosa Maria +2 more
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