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Air trapped in ice core bubbles provides our primary source of information about past atmospheres. Air isotopic composition (15N/14N and 40Ar/36Ar) permits an estimate of the temperature shifts associated with abrupt climate changes because of isotope frac ...
The Vostok core provides the longest ice record of past climatic and environmental conditions, extending back to the interglacial Marine Isotope Stage (MIS) 11, around 400 kyr ago. The MIS 11 information obtained from different time series at Vostok, namel ...
RECORDS of the variation in atmospheric methane concentration have been obtained from ice cores for the past 1,000 years and for the period 8,000-220,000 yr BP (refs 1-4), but data for the intervening period, spanning most of the present interglacial perio ...
Selective IR vibrational predissocn. (IRVP) of van der Waals clusters in a free jet is an effective way to sep. isotopes. Abs. sepn. factors a in excess of 1.1 were obsd. upon irradn. of a beam of SF6 dild. in Ar with a 20 W CO2 laser. Selection of the wav ...
The separation of hydrogen isotopes for applications such as nuclear fusion is a major challenge. Current technologies are energy intensive and inefficient. Nanoporous materials have the potential to separate hydrogen isotopes by kinetic quantum sieving, b ...
Quantitative Secondary Ion Mass Spectrometry (SIMS) determination of oxygen incorporation in epitaxial AlGaAs/GaAs layers is strongly affected by the presence of oxygen adsorbed on the surface. By flooding the sample with oxygen isotope O18 during the anal ...
The authors have produced YBaCuO thin films by mono-target ion beam sputtering. Post annealing in O2 at 850°C results in superconducting films on (100) SrTiO3 with R=0 at ~60 K. Preliminary results of chemical analysis of the films by X-ray photoelectron s ...
The efficiency of conventional aerodynamic isotope sepn. can be improved by 2 orders of magnitude with the aid of a relatively weak cw IR laser which is used to induce isotopically selective condensation. Overall isotope enrichment factors in excess of 2 a ...
The alcoholate-induced dehydrochlorination of styryl chloride possibly occurs by the 3 different competing mechanisms: E2, E1cb, and E1cb-HBA an E1cb modification. These conclusions were confirmed by H-D exchange, isotope effects, order of reaction, and re ...
