نتایج جستجو برای: noble gases
تعداد نتایج: 50564 فیلتر نتایج به سال:
The synthesis of a long-lived, truxene-based radical that is highly delocalized and exhibits a narrow EPR absorption is reported. The radical is stable for multiple hours in a solution exposed to air and remains for months in the solid state under inert gas. Characterization and properties are discussed.
INTRODUCTION We are developing a new diagnostic technology: magnetic resonance imaging (MRI) and spectroscopy of hyperpolarized noble gases. Large non-equilibrium nuclear spin polarizations can be created in the spin-1/2 noble gases, He and Xe, using the technique of spin-exchange optical pumping. Such large polarizations greatly enhance the magnetic resonance detection of He and Xe, enabling h...
Here we present a new method for the sampling and quantitative extraction of dissolved He, Ne, Ar, Kr, and Xe from lake sediment samples leading to determinations of porewater noble gas concentration profiles and the isotopic ratios 3He/4He, 20Ne/22Ne, and 40Ar/36Ar. Bulk sediment is transferred from a sediment core into standard Cu sample tubes without exposure to the atmosphere or other gas r...
Reid DD and Wadehra JM. Low-energy differential scattering of electrons and positrons from noble gases.
Polar ice cores constitute excellent archives of past environmental conditions and provide us with glimpses into the Earth’s climatic history over hundreds of thousands of years. For the past two decades, noble gases, used as conservative tracers, have played a substantial role in extracting information from these archives. Noble gas analysis can be performed on two types of ice core samples. F...
A Geochemical Approach for Monitoring a CO2 Pilot Site: Rousse, France. A Major Gases, CO2-Carbon Isotopes and Noble Gases Combined Approach — This paper presents the geochemical characterization of various gas end-members involved in a depleted gas field CO2 storage pilot (Rousse, France). In this pilot, CO2 is produced by oxycombustion from natural gas transformed into fuel gas at the Lacq pl...
The adsorption of rare gases on metal surfaces serves as the paradigm of weak adsorption where it is typically assumed that the adsorbate occupies maximally coordinated hollow sites. Density-functional theory calculations using the full-potential linearized augmented plane wave method for Xe adatoms on Mg(0001), Al(111), Ti(0001), Cu(111), Pd(111), and Pt(111), show, however, that Xe prefers lo...
The problem of radon in dwellings gained importance in 1984 after an incidence in Pennsylvania, USA; thereafter several measuring techniques have been developed and national survey programs were started throughout the world for monitoring radon levels by government authorities. The lots of work have done by researchers in this field throughout the world. Several developed countries have given g...
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