Concept

Fractionnement isotopique

Publications associées (87)

Rapid climate variability during warm and cold periods in polar regions and Europe [Variabilité climatique rapide pendant les périodes chaudes et froides aux pôles et en Europe]

Isotopic mass spectrometry coupled online with gas chromatography (GC-C-IRMS) permits measurement of relative proportions of gaseous hydrocarbon (CH4 to C4H10) and CO2, and determination of carbon isotope ratio of hydrocarbon molecules. Access to these par ...

Elsevier BV2005

The 2D MAS NMR spin-echo experiment: the determination of C-13-C-13 J couplings in a solid-state cellulose sample

David Lyndon Emsley

A simple C-13 MAS spin-echo experiment is applied to a partially C-13-labelled cellulose sample extracted from wood. C-13-C-13 J couplings are determined even though considerable chemical disorder leads to observed linewidths in the normal 1D C-13 CP MAS s ...

ACADEMIC PRESS INC ELSEVIER SCIENCE2004

Combined element (H and C) stable isotope ratios of methane in carbonaceous chondrites

Jérôme Chappellaz

Pulse-like carbon dioxide release to the atmosphere on centennial time scales has only been identified for the most recent glacial and deglacial periods and is thought to be absent during warmer climate conditions. Here, we present a high-resolution carbon ...

American Association for the Advancement of Science (AAAS)2004

Climate and interannual variability of the atmosphere-biosphere 13CO2 flux

Jed Oliver Kaplan

We present a bottom-up approach to simulate the terrestrial isotopic carbon variations using the Lund-Potsdam-Jena dynamic global vegetation model (LPJ-DGVM). LPJ is extended to include isotopic fractionation of C-13 at the leaf level during assimilation a ...

2003

Influence of the growth substrate on ester-linked phospho- and glycolipid fatty acids of PAH-degrading Mycobacterium sp LB501T

The influences of poorly water-soluble anthracene on ester-linked phospholipid fatty acid (PLFA) and glycolipid fatty acid (GLFA) profiles of Mycobacterium sp. LB501T were studied. Bacteria were cultivated on either anthracene or glucose (one culture with ...

Wiley-Blackwell2003

Are high He-3/He-4 ratios in oceanic basalts an indicator of deep-mantle plume components?

Anders Meibom, Reto Frei

The existence of a primordial, undegassed lower mantle reservoir characterized by high concentration of He-3 and high He-3/He-4 ratios is a cornerstone assumption in modern geochemistry. It has become standard practice to interpret high He-3/He-4 ratios in ...

2003

Collisionally enhanced isotopic selectivity in multiphoton dissociation of vibrationally excited CF3H

Thomas Rizzo, Monika Kowalczyk

We have studied infrared multiphoton dissociation of CF3H pre-excited to the second C-H stretch overtone under collisional conditions in view of developing a laser isotope separation scheme for carbon-13. This single stage process results in a C2F4 product ...

2003

Protein fractionation in a multicompartment device using Off-Gel(TM) isoelectric focusing

Hubert Girault, Joël Stéphane Rossier

A new protein fractionation technique based on off-gel isoelectric focusing (IEF) is presented, where the proteins are separated according to their isoelectric point (pI) in a multiwell device with the advantage to be directly recovered in solution for fur ...

Wiley-Blackwell2003

Isotopically selective infrared multiphoton dissociation of vibrationally excited SiH4

Thomas Rizzo, Joachim Makowe

We use mass-resolved 2+2 resonantly enhanced multiphoton ionization (REMPD of silicon atoms to detect isotopically selective infrared multiphoton dissociation (IRMPD) of both ground-state and vibrationally pre-excited SiH4. To demonstrate that the detectio ...

2002

Mode of occurrence, textural settings and nitrogen-isotopic compositions of in situ diamonds and other carbon phases in the Bencubbin meteorite

Philippe Gillet

Investigations on a polished thin section (PTS) by reflected-light microscopy, laser micro-Raman spectroscopy, and cathodoluminescence of the Bencubbin meteorite revealed the presence of diamond grains ranging in size from 200 nm to 1 mum in Fe-Ni metal, s ...

2002

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