Search results for "GASES"
showing 10 items of 1098 documents
In-trap conversion electron spectroscopy
2002
The Penning trap REXTRAP at ISOLDE was used to test the feasibility of in-trap conversion electron spectroscopy. The results of simulations, experiments with solid conversion electron sources as well as first on-line and tests with trapped radioactive ions are presented. In addition to obtaining high-resolution spectroscopic data, the detection of conversion electrons was found to be a useful tool for the diagnostics of the trap operation. The tests proved the feasibility of in-trap spectroscopy but also revealed some potential problems to be addressed in the future.
Mixed-Valence Magnetic Molecular Cell for Quantum Cellular Automata: Prospects of Designing Multifunctional Devices through Exploration of Double Exc…
2020
In this article, we propose to use multielectron square-planar mixed-valence (MV) molecules as molecular cells for quantum cellular automata (QCA) devices. As distinguished from previous proposals ...
A Nonlinear Nonviscous Hydrodynamical Model for Change Transport Derived from Kinetic Theory
2002
In the paper, methods of Extended Thermodynamics are used to derive nonlinear closure relations for hydrodynamical models for charge transport in metals or in semiconductors, neglecting viscous phenomena. For the sake of simplicity only the case of single parabolic band approximation is studied. In this work the velocity v i is not considered as a small parameter; therefore, the models obtained can be useful when one wishes to study phenomena in a neighborhood of a stationary non-equilibrium process.
Exploring Interacting Topological Insulators with Ultracold Atoms: The Synthetic Creutz-Hubbard Model
2016
25 pags., 13 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0
Thermalization in the initial stage of heavy ion collisions
2017
The high density non-abelian matter produced in heavy ion collisions is extremely anisotropic. Prethermal dynamics for the anisotropic and weakly coupled matter is discussed. Thermalization is realized with the effective kinetic theory in the leading order accuracy of the weakly coupled expansion. With the initial condition from color glass condensate, hydrodynamization time for the LHC energies is realized to be about 1 fm/c, while the thermalization happens much later than the hydrodynamization. peerReviewed
Polikristāla kušanas un termomehānisko spriegumu trīsdimensionāla matemātiskā modelēšana peldošās zonas silīcija kristālu audzēšanas procesā : Promoc…
2021
Silīcija monokristālu audzēšanas procesā ar peldošās zonas metodi indukcijas spoles forma un materiālo īpašību anizotropija nosaka būtiskākās fizikālo lauku novirzes no aksiālās simetrijas. Šajā darbā tas ievērots, skaitliski modelējot silīcija fāžu robežas un termomehāniskos spriegumus kristālā trijās dimensijās, kas līdz šim literatūrā neparādās. Modelis atklātās kušanas frontes formai validēts ar mērījumiem no eksperimenta tipiskam 4 collu procesam, kvantitatīvi nosakot asimetriju polikristāla ārmalā, kur atrodas elektromagnētiskā lauka maksimums virs spraugas starp induktora strāvas pievadiem. Atrasti lielāki termomehāniskie spriegumi pie kristālam raksturīgās augšanas šķautnes zem trīs…
Solving the heat-flow problem with transient relativistic fluid dynamics
2014
Israel-Stewart theory is a causal, stable formulation of relativistic dissipative fluid dynamics. This theory has been shown to give a decent description of the dynamical behavior of a relativistic fluid in cases where shear stress becomes important. In principle, it should also be applicable to situations where heat flow becomes important. However, it has been shown that there are cases where Israel-Stewart theory cannot reproduce phenomena associated with heat flow. In this paper, we derive a relativistic dissipative fluid-dynamical theory from kinetic theory which provides a good description of all dissipative phenomena, including heat flow. We explicitly demonstrate this by comparing th…
Kinetic model for steady heat flow
1986
We construct a consistent solution of the Bhatnagar-Gross-Krook (BGK) model kinetic equation describing a system in a steady state with constant pressure and nonuniform temperature. The thermal profile is not linear and depends on the interaction potential. All the moments of the distribution function are given as polynomials in the local thermal gradient. In particular, the heat flux always obeys the (linear) Fourier law.
Relative importance of second-order terms in relativistic dissipative fluid dynamics
2014
[Introduction] In Denicol et al. [Phys. Rev. D 85 , 114047 (2012)], the equations of motion of relativistic dissipative fluid dynamics were derived from the relativistic Boltzmann equation. These equations contain a multitude of terms of second order in the Knudsen number, in the inverse Reynolds number, or their product. Terms of second order in the Knudsen number give rise to nonhyperbolic (and thus acausal) behavior and must be neglected in (numerical) solutions of relativistic dissipative fluid dynamics. The coefficients of the terms which are of the order of the product of Knudsen and inverse Reynolds numbers have been explicitly computed in the above reference, in the limit of a massl…
Subsecond fluorine-19 MRI of the lung
2006
Minimal scan times in rapid fluorine-19 MRI using sulfur hexafluoride (SF6) have been on the order of 10 s. Because of the very short T1 relaxation time of SF6 (T1 = 1.65 ms), high receiver bandwidths are necessary to allow for a high number of excitations. Since high bandwidths cause high levels of electronic noise, SNR per acquisition has been too low to further reduce scan time. The purpose of this study was to investigate whether scan times could be reduced using hexafluoroethane (C2F6), a gas with a longer T1 (T1 = 7.9 ms) at a relatively low bandwidth of 488 Hz/pixel. Gradient-echo images were acquired during and after completion of the wash-in of a 70% C2F6- 30% O2 mixture. Peak SNR …