Search results for "Pumping"
showing 8 items of 198 documents
High-contrast sub-Doppler absorption spikes in a hot atomic vapor cell exposed to a dual-frequency laser field
2017
International audience; The saturated absorption technique is an elegant method widely used in atomic and molecular physics for high-resolution spectroscopy, laser frequency standards and metrology purposes. We have recently discovered that a saturated absorption scheme with a dual-frequency laser can lead to a significant sign reversal of the usual Doppler-free dip, yielding a deep enhanced-absorption spike. In this paper, we report detailed experimental investigations of this phenomenon, together with a full in-depth theoretical description. It is shown that several physical effects can support or oppose the formation of the high-contrast central spike in the absorption profile. The physi…
Distribution and generation of traps in SiO2/Al2O3 gate stacks
2007
In this work we combine charge-pumping measurements with positive constant voltage stress to investigate trap generation in SiO2/ Al2O3 n-MOSFET. Trap density has been scanned either in energy or in position based on charge-pumping (CP) measurements performed under different operating conditions in terms of amplitude and frequency of the gate pulse. Our results have revealed that the traps are meanly localized shallow in energy level, deeper in spatial position and they are mostly generated near the Si/SiO2 interface. (C) 2007 Elsevier Ltd. All rights reserved.
An Approach to Delineate Groundwater Bodies at Risk: Seawater Intrusion in Liepāja (Latvia)
2018
Groundwater quality in coastal areas is frequently affected by seawater intrusion as a consequence of intensive water consumption. To achieve “good chemical status” of a groundwater body according to Water Framework Directive the effects of saline or other intrusions should not be observed. Groundwater pumping in former decades has caused a significant seawater intrusion into confined aquifer in Liepāja and has led to deterioration of relatively wide coastal area of the third largest city in Latvia. However, the area affected by seawater intrusion is a small part of groundwater body F1 which overall chemical status is good. Thus, no specific management measures have been applied to explore …
Mechanical circulatory support. An expert opinion of the Association of Intensive Cardiac Care and the Association of Cardiovascular Interventions of…
2021
Mechanical circulatory support (MCS) methods are used in patients with both acute and chronic heart failure, who have exhausted other options for pharmacological or surgical treatments. The purpose of their use is to support, partially or completely, the failed ventricles and ensure adequate organ perfusion, which allows patients to restore full cardiovascular capacity, prolonging their life and effectively improving its quality. The three most popular devices include an intra-aortic balloon pump (IABP), percutaneous assist devices (including Impella, TandemHeart), and venoarterial extracorporeal membrane oxygenation (VA-ECMO). A multidisciplinary approach with the special participation of …
Nonroutine Use of Intra-Aortic Balloon Pump in Cardiogenic Shock Complicating Myocardial Infarction With Successful and Unsuccessful Primary Percutan…
2018
Abstract Objectives The authors sought to compare outcomes of patients with myocardial infarction and cardiogenic shock (CS) treated with percutaneous coronary intervention (PCI) with or without intra-aortic balloon pump (IABP) support according to final epicardial flow in the infarct-related artery. Background A routine use of IABP is contraindicated in patients with myocardial infarction and CS. There are no data regarding the subpopulation of patients who may benefit from such support besides patients with mechanical complications of myocardial infarction. Methods Prospective nationwide registry data of patients with myocardial infarction and CS treated with PCI between 2003 and 2014 wer…
FIBRE OPTICAL COUPLER SIMULATION BY COMSOL MULTIPHYSICS SOFTWARE
2022
Funding: The research has been supported by the European Regional Development Fund project No.1.1.1.1/18/A/068. The Institute of Solid State Physics, University of Latvia as a Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.
Finite-frequency spin susceptibility and spin pumping in superconductors with spin-orbit relaxation
2020
Static spin susceptibility of superconductors with spin-orbit relaxation has been calculated in the seminal work of A.A. Abrikosov and L.P. Gor'kov [Sov. Phys. JETP, {\bf 15}, 752 (1962)]. Surprisingly the generalization of this result to finite frequencies has not been done despite being quite important for the modern topic of superconducting spintronics. The present paper fills this gap by deriving the analytical expression for spin susceptibility. The time-dependent spin response is shown to be captured by the quasiclassical Eilenberger equation with collision integrals corresponding to the ordinary and spin-orbit scattering. Using the developed formalism we study the linear spin pumping…
Spin Pumping and Torque Statistics in the Quantum Noise Limit
2017
We analyze the statistics of charge and energy currents and spin torque in a metallic nanomagnet coupled to a large magnetic metal via a tunnel contact. We derive a Keldysh action for the tunnel barrier, describing the stochastic currents in the presence of a magnetization precessing with the rate Ω. In contrast to some earlier approaches, our result is valid for an arbitrary ratio of ℏΩ/kBT. We illustrate the use of the action by deriving spintronic fluctuation relations, the quantum limit of pumped current noise, and consider the fluctuations in two specific cases: the situation with a stable precession of magnetization driven by spin transfer torque, and the torque-induced switching betw…