Search results for "ele"
showing 10 items of 69718 documents
Análisis de la utilidad del algoritmo Gradient Boosting Machine (GBM) en la predicción del fracaso empresarial
2018
Este estudio, novedoso en cuanto a la utilizacion de la metodologia basada en la cultura de los algoritmos, prueba la capacidad de la tecnica ‘Gradient Boosting Machine’ (GBM) en la prediccion de l...
Restricted compositions and permutations: from old to new Gray codes
2011
Any Gray code for a set of combinatorial objects defines a total order relation on this set: x is less than y if and only if y occurs after x in the Gray code list. Let @? denote the order relation induced by the classical Gray code for the product set (the natural extension of the Binary Reflected Gray Code to k-ary tuples). The restriction of @? to the set of compositions and bounded compositions gives known Gray codes for those sets. Here we show that @? restricted to the set of bounded compositions of an interval yields still a Gray code. An n-composition of an interval is an n-tuple of integers whose sum lies between two integers; and the set of bounded n-compositions of an interval si…
Controlled turbulence regime of electron cyclotron resonance ion source for improved multicharged ion performance
2020
Fundamental studies of excitation and non-linear evolution of kinetic instabilities of strongly nonequlibrium hot plasmas confined in open magnetic traps suggest new opportunities for fine-tuning of conventional electron cyclotron resonance (ECR) ion sources. These devices are widely used for the production of particle beams of high charge state ions. Operating the ion source in controlled turbulence regime allows increasing the absorbed power density and therefore the volumetric plasma energy content in the dense part of the discharge surrounded by the ECR surface, which leads to enhanced beam currents of high charge state ions. We report experiments at the ECR ion source at the JYFL accel…
Effect of space charge on the negative oxygen flux during reactive sputtering
2017
Negative ions often play a distinctive role in the phase formation during reactive sputter deposition. The path of these high energetic ions is often assumed to be straight. In this paper, it is shown that in the context of reactive magnetron sputtering space charge effects are decisive for the energetic negative ion trajectories. To investigate the effect of space charge spreading, reactive magnetron sputter experiments were performed in compound mode with target materials that are expected to have a high secondary ion emission yield (MgO and CeO2). By the combination of energy flux measurements, and simulations, a quantitative value for the negative oxygen ion yield can be derived.
Determination of an empirical law of aluminium and magnesium alloys absorption coefficient during Nd :YAG laser interaction
2007
International audience; Welding laser modelling requires knowledge about relative changes of many thermo-physical parameters involved in the interaction. The absorptivity of the material is one of the most important. In this study, experimental measurements of absorptivity with an integrating sphere on two alloys (aluminium and magnesium) were made. These results were compared with an analytical calculation that takes into account the trapping of the beam by multiple reflections inside the keyhole. Based on a statistical method, an empirical law is proposed connecting absorptivity with the peak power of the laser and the duration of interaction. During the interaction, two distinct phenomen…
Impact of the erase algorithms on flash memory lifetime
2017
This paper presents a comparative study on the impact of the erase algorithm on flash memory lifetime, to demonstrate how the reduction of overall stress, suffered by memories, will increase their lifetime, thanks to a smart management of erase operations. To this purpose a fixed erase voltage, equal to the maximum value and the maximum time-window, was taken as the reference test; while an algorithm with adaptive voltage levels and the same overall time-window was designed and implemented in order to compare their experimental results. This study was carried out by using an innovative Automated Test Equipment, named Portable-ATE, tailored for Memory Test Chip and designed for performance e…
Coloration mechanism of electrochromic Na x WO3 thin films
2019
International audience; The coloration mechanism of tungsten trioxide (WO3) upon insertion of alkali ions is still under debate after several decades of research. This Letter provides new insights into the reversible insertion and coloration mechanisms of Na+ ions in WO3 thin films sputter-deposited on ITO/glass substrates. A unique model based on a constrained spline approach was developed and applied to draw out ε1+iε2 from spectroscopic ellipsometry data from 0.6 to 4.8 eV whatever the state of the electrochromic active layer, i.e. as-deposited, colored or bleached. It is shown that electrochemically intercalated sodium-tungsten trioxide, NaxWO3 (x=0.1, 0.2, 0.35), exhibits an absorption…
First principles hybrid Hartree-Fock-DFT calculations of bulk and (001) surface F centers in oxide perovskites and alkaline-earth fluorides
2020
Valuable discussions with E. A. Kotomin are gratefully acknowledged. Research contribution of R. E. and A. I. P. has been performed within the framework of the EUROfusion Enabling Research project: ENR-MFE19.ISSP-UL-02 “Advanced experimental and theoretical analysis of defect evolution and structural disordering in optical and dielectric materials for fusion applications.” The views and opinions expressed herein do not necessarily reflect those of the European Commission.
Migration kinetics of ion-implanted beryllium in glassy carbon
2008
Abstract Migration kinetics of low-concentration implanted 7 Be in glassy carbon has been studied by the modified radiotracer technique at temperatures 1285 °C and 1340 °C. The annealed sample concentration profiles show two distinctive components: (i) Main profile broadening assigned to beryllium trapping in defects during annealing. (ii) Tail parts on both sides of the profile maximum related to faster migration. Of the latter the profile representing bulk diffusion lies on the region free of defect influence and is well described by concentration-independent diffusivity. The features of the concentration profile broadening towards the sample surface indicate partial Be trapping in defect…
Evolution of the microstructure of sputter deposited TaAlON thin films with increasing oxygen partial pressure
2021
Abstract Recently, quaternary oxynitrides of transition metals and aluminum have attracted increasing interest due to their tunable properties. Within the present work, a series of TaAl(O)N films was sputter deposited using constant nitrogen and varying oxygen partial pressures. The films were grown from single element Ta and Al targets. The deposition parameters were adjusted to obtain a Ta/Al atomic ratio of ~50/50 for the oxygen-free film and were held constant for the following depositions, with the exception of the increasing oxygen partial pressure and compensatory decreasing argon partial pressure. Elastic recoil detection analysis revealed oxygen contents of up to ~26 at.%, while th…