نتایج جستجو برای: helium purification
تعداد نتایج: 71071 فیلتر نتایج به سال:
This paper introduces a nonlinear Schrr odinger model for superruid that captures the process of mutual friction between the superruid and normal uid components of helium II. Superruid vortices are identiied as topological defects in the solution of this equation. A matched asymptotic analysis of Neu 7] is adapted to derive an asymptotic dynamics for the vortices in the case they are widely sep...
We present evolutionary models of helium accreting carbon-oxygen white dwarfs in which we include the effects of the spin-up of the accreting star induced by angular momentum accretion, rotationally induced chemical mixing and rotational energy dissipation. Initial masses of 0.6 M⊙ and 0.8 M⊙ and constant accretion rates of a few times 10−8M⊙/yr of helium rich matter have been considered, which...
Helium at low temperatures has unique quantum properties such as superfluidity, which causes it to behave differently from a classical fluid. Despite our deep understanding of quantum mechanics, there are many open questions concerning the properties of quantum fluids in nanoscale systems. Herein, the quantum behavior of helium transportation through one-dimensional nanopores was evaluated by m...
Suicide by helium inhalation inside a plastic bag has recently been publicized by right-to-die proponents in "how to" print and videotape materials. This article reports a suicide performed according to this new and highly lethal technique, which is also a potentially undetectable cause of death. Toxicology information could not determine helium inhalation, and drug screening did not reveal dat...
Excitation spectra up to the ionization threshold are reported for barium atoms located on the surface of helium nanodroplets. For states with low principal quantum number, the resonances are substantially broadened and shifted towards higher energy with respect to the gas phase. This has been attributed to the repulsive interaction of the excited atom with the helium at the Franck-Condon regio...
Helium has a unique phase diagram and below 25 bar it does not form a solid even at the lowest temperatures. Electrostriction leads to the formation of a solid layer of helium around charged impurities at much lower pressures in liquid and superfluid helium. These so-called 'Atkins snowballs' have been investigated for several simple ions. Here we form HenC60+ complexes with n exceeding 100 via...
für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namen...
The effect of helium in iron is an important issue in nuclear systems, as iron and iron alloys (steels) are the primary materials used for structural elements. Helium is known to cause embrittlement and decrease fatigue life, as well as aid creep and promote swelling. These effects can significantly alter the mechanical properties of the reactor materials, and generally lead to early failure an...
This paper is the first of a two-part series dealing with quantum-mechanical (density-functional-based) studies of helium-mediated deposition of catalytic species on the rutile TiO(2)(110)-(1×1) surface. The interaction of helium with the TiO(2)(110)-(1×1) surface is first evaluated using the Perdew-Burke-Ernzerhof functional at a numerical grid dense enough to build an analytical three-dimensi...
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