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Littérature scientifique sur le sujet « Solid-to-plasma transition »

Auteur : Grafiati

Publié le 11 janvier 2025

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Articles de revues sur le sujet "Solid-to-plasma transition"

Ferguson, Ken R., Maximilian Bucher, Tais Gorkhover, Sébastien Boutet, Hironobu Fukuzawa, Jason E. Koglin, Yoshiaki Kumagai et al. « Transient lattice contraction in the solid-to-plasma transition ». Science Advances 2, n^o 1 (janvier 2016) : e1500837. http://dx.doi.org/10.1126/sciadv.1500837.

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In condensed matter systems, strong optical excitations can induce phonon-driven processes that alter their mechanical properties. We report on a new phenomenon where a massive electronic excitation induces a collective change in the bond character that leads to transient lattice contraction. Single large van der Waals clusters were isochorically heated to a nanoplasma state with an intense 10-fs x-ray (pump) pulse. The structural evolution of the nanoplasma was probed with a second intense x-ray (probe) pulse, showing systematic contraction stemming from electron delocalization during the solid-to-plasma transition. These findings are relevant for any material in extreme conditions ranging from the time evolution of warm or hot dense matter to ultrafast imaging with intense x-ray pulses or, more generally, any situation that involves a condensed matter-to-plasma transition.

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Dorchies, F., et V. Recoules. « Non-equilibrium solid-to-plasma transition dynamics using XANES diagnostic ». Physics Reports 657 (octobre 2016) : 1–26. http://dx.doi.org/10.1016/j.physrep.2016.08.003.

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Liu, Chen, Andriani Mentzelopoulou, Fotini Papagavriil, Prashanth Ramachandran, Artemis Perraki, Lucas Claus, Sebastian Barg et al. « SEC14-like condensate phase transitions at plasma membranes regulate root growth in Arabidopsis ». PLOS Biology 21, n^o 9 (18 septembre 2023) : e3002305. http://dx.doi.org/10.1371/journal.pbio.3002305.

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Protein function can be modulated by phase transitions in their material properties, which can range from liquid- to solid-like; yet, the mechanisms that drive these transitions and whether they are important for physiology are still unknown. In the model plant Arabidopsis, we show that developmental robustness is reinforced by phase transitions of the plasma membrane-bound lipid-binding protein SEC14-like. Using imaging, genetics, and in vitro reconstitution experiments, we show that SEC14-like undergoes liquid-like phase separation in the root stem cells. Outside the stem cell niche, SEC14-like associates with the caspase-like protease separase and conserved microtubule motors at unique polar plasma membrane interfaces. In these interfaces, SEC14-like undergoes processing by separase, which promotes its liquid-to-solid transition. This transition is important for root development, as lines expressing an uncleavable SEC14-like variant or mutants of separase and associated microtubule motors show similar developmental phenotypes. Furthermore, the processed and solidified but not the liquid form of SEC14-like interacts with and regulates the polarity of the auxin efflux carrier PINFORMED2. This work demonstrates that robust development can involve liquid-to-solid transitions mediated by proteolysis at unique plasma membrane interfaces.

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Wang, Xin-Ke, Igor Veremchuk, Matej Bobnar, Jing-Tai Zhao et Yuri Grin. « Solid solution Pb1−xEuxTe : constitution and thermoelectric behavior ». Inorganic Chemistry Frontiers 3, n^o 9 (2016) : 1152–59. http://dx.doi.org/10.1039/c6qi00161k.

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The thermoelectric properties of polycrystalline materials on the basis of the solid solution Pb_1−xEu_xTe prepared by spark-plasma-sintering are characterized. The solid solution undergoes a metal–semiconductor transition in parallel to the p–n transition around 500 K.

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FISHER, DIMITRI V., ZOHAR HENIS, SHALOM ELIEZER et JUERGEN MEYER-TER-VEHN. « Core holes, charge disorder, and transition from metallic to plasma properties in ultrashort pulse irradiation of metals ». Laser and Particle Beams 24, n^o 1 (mars 2006) : 81–94. http://dx.doi.org/10.1017/s0263034606060137.

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We study the details of a gradual change in electron properties from those of a nearly-free-electron (NFE) metal to those of a strongly-coupled plasma, in ultrashort pulse energy deposition in solid metal targets. Time scales shorter than those of a target surface layer expansion are considered. Both the case of an optical laser (visible or near infrared wavelengths range) and of a free electron laser (vacuum ultraviolet or X-ray) are treated. The mechanisms responsible for the change in electron behavior are isochoric melting, lattice charge disordering, and electron mean free path reduction. We find that the transition from metal to plasma usually occurs via an intermediate stage of a charge-disordered solid (solid plasma), in which ions are at their lattice sites but the ionization stages of individual ions differ due to ionization from localized bound states. Charge disordered state formation is very rapid (typically, few femtoseconds or few tens of femtoseconds). Pathway to charge-disordered state differs in simple metals and in noble metals. Probabilities are derived for electron impact ionization and 3-body recombination of a bound ionic state in solid-density medium, applicable both in metal and in plasma regime. An evolution of energy coupling between electron and ion subsystems, from metallic electron-phonon (e-ph) to plasma electron-ion (e-i) coupling, is considered. Substantial increase in coupling parameter is expected as a result of charge disorder.

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Smirnova, K. V., D. A. Shutov, A. N. Ivanov et V. V. Rybkin. « Plasma-solution synthesis of particles containing transition metals ». Journal of Physics : Conference Series 2064, n^o 1 (1 novembre 2021) : 012096. http://dx.doi.org/10.1088/1742-6596/2064/1/012096.

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Abstract The paper proposes a new method for the synthesis of powders containing transition metals using a plasma-solution system. The reactor was an H-shaped glass cell, the two parts of which were separated by a cellophane membrane. A discharge consisting of two discharges - with a liquid cathode and a liquid anode - a high voltage is applied to titanium electrodes located above the surface of the solution. Aqueous solutions of zinc, iron, cadmium, cobalt, nickel, and copper nitrates were used as the liquid phase. Under the action of the discharge on the liquid anode, in the region of contact of the discharge with the solution the formation of a colloidal suspension was observed. The kinetics of the process of synthesis of solid-phase particles in solution under the action of a discharge have been studied. The chemical composition and morphology of the formed solid phase have been established. The mechanisms of chemical reactions occurring in the solution under the action of plasma, and the mechanisms of formation of transition metal oxides in the process of calcining the synthesized powders have been proposed.

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Singh, Swarnima, P. Bandyopadhyay, Krishan Kumar, M. G. Hariprasad, S. Arumugam et A. Sen. « Transition of a 2D crystal to a non-equilibrium two-phase coexistence state ». Physics of Plasmas 30, n^o 4 (avril 2023) : 043704. http://dx.doi.org/10.1063/5.0139228.

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In this paper, we present experimental observation of the transition of a 2D dust crystal to a non-equilibrium solid–liquid phase coexistence state. The experiments have been carried out in an L-shaped dusty plasma experimental device in a DC glow discharge argon plasma environment. Initially, a monolayer crystalline structure is formed, which is later transformed to a two-phase coexistence state using the background neutral pressure as a control parameter. Self-excited horizontal oscillations are found in the center of the monolayer prior to the appearance of the coexistence state. It is observed that a molten center coexists with a solid periphery. Various structural, thermodynamic, and dynamical quantities are used to characterize the phase state. The surface tension at the solid–liquid circular interface is also determined. A detailed parametric study is made to delineate the existence region of such a state. It is found that melting caused at the core is due to the onset of a localized Schweigert instability in the presence of a few stray particles beneath the top layer in that region.

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Rao, Lin, Edward G. Gillan et Richard B. Kaner. « Rapid synthesis of transition-metal borides by solid-state metathesis ». Journal of Materials Research 10, n^o 2 (février 1995) : 353–61. http://dx.doi.org/10.1557/jmr.1995.0353.

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A rapid self-sustaining solid-state precursor route to transition-metal borides, boride solid solutions, and boride composites has been developed. Solid-state metathesis (SSM) reactions between transition-metal chlorides and magnesium boride (MgB2) produce crystalline borides and magnesium chloride. Boride solid solutions are formed using mixed chloride precursors. By using a third precursor, such as NaN3, boride-nitride composites are synthesized. The reaction products are characterized by powder x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and inductively coupled plasma atomic absorption spectroscopy. These boride reactions become self-propagating when the adiabatic temperature is greater than the melting point of the by-product salt, MgCl2 (mp 987 K).

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Yeh, F. B., et P. S. Wei. « Effects of Plasma Parameters on the Temperature Field in a Workpiece Experiencing Solid-Liquid Phase Transition ». Journal of Heat Transfer 127, n^o 9 (27 avril 2005) : 987–94. http://dx.doi.org/10.1115/1.1999653.

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The heat transfer characteristics of a workpiece subject to plasma heating and melting are theoretically and systematically studied. Plasma etching, spray deposition, sputtering, cutting and surface treatment, etc., are usually controlled by energy transfer from plasma to workpieces. In this work, the one-dimensional unsteady conduction equation accounting for solid-liquid phase transition with distinct thermal properties in a workpiece is solved. The plasma is composed of a collisionless presheath and sheath on an electrically floating workpiece that partially reflects or secondarily emits ions and electrons. The energy transport from plasma to the surface is kinetically, analytically and exactly calculated from self-consistent velocity distributions of the ions and electrons. The results show that the predicted surface temperature and energy transmission factor agree well with experimental data. The effects of plasma characteristics and thermal parameters of the workpiece on unsteady temperature profiles and thickness of the molten layer in the workpiece are quantitatively provided in this work. Energy released from recombination of the ions and electrons on the surface is found to play the most important role on heating the workpiece. The deviation of surface temperature contributed by recombination energy can be 1000 K.

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Tachibana, K., et Y. Hayashi. « Analysis of the Coulomb-solidification Process in Particle Plasmas ». Australian Journal of Physics 48, n^o 3 (1995) : 469. http://dx.doi.org/10.1071/ph950469.

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The Coulomb-solidification process is analysed using Mie-scattering ellipsometry with the assistance of photography and scanning electron microscopy. Spherical monodisperse carbon particles are observed to grow in a methane plasma. The Coulomb-coupling parameter at the liquid-to-solid phase transition is evaluated to be around 200, which is close to the value predicted by a Monte Carlo simulation. The growth of monodisperse particles of pss: size having the same charge favours the formation of a Coulomb solid.

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Thèses sur le sujet "Solid-to-plasma transition"

Liotard, Romain. « Étude de la transition solide-plasma du polystyrène et de son influence sur les simulations de fusion par confinement inertiel en attaque directe ». Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0222.

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La fusion par confinement inertiel (FCI) en attaque directe est une méthode envisagée pour obtenir une réaction de fusion nucléaire en irradiant une cible avec plusieurs impulsions laser de haute intensité. Cette cible est une sphère constituée d'un matériau solide appelé ablateur (généralement du polystyrène), entourant un combustible de fusion (généralement du deutérium-tritium (DT) cryogénique). L'énergie apportée par l'irradiation laser provoque l'éjection de l’ablateur et l'implosion de la cible par effet fusée. Le travail mécanique exercé sur le point chaud (le centre de la cible) pendant l'implosion doit permettre de déclencher des réactions de fusion. Actuellement, les codes hydrodynamiques radiatifs utilisés pour simuler les implosions de FCI supposent généralement que l'ablateur est initialement à l'état plasma, bien qu'il soit à l'état solide. Cet état solide pourrait jouer un rôle lors de l'interaction initiale entre les lasers et la cible. En raison de la transparence initiale de l'ablateur, le laser peut pénétrer la cible, ce qui est appelé l'effet de "shine-through", et modifier le dépôt d'énergie laser, ce qui peut conduire à une modification de la dynamique des chocs se propageant dans la cible. De plus, les modifications de l’empreinte laser peuvent influencer l’évolution des instabilités hydrodynamiques au cours de l’implosion.L’objectif de cette thèse est de développer un modèle de transition solide-plasma du polystyrène fondé sur les modèles existants et pouvant être intégré aux codes hydrodynamiques de simulation de FCI. Pour ce faire, il a fallu adapter le modèle aux contraintes spécifiques de ces codes, en tenant compte des dépendances du modèle vis-à-vis de l'évolution de toutes les grandeurs hydrodynamiques, et en optimisant les coûts numériques pour éviter une augmentation excessive du temps de simulation. L'intégration de ces modifications a requis une validation expérimentale du modèle, effectuée grâce à une expérience réalisée sur le laser GCLT du CEA-DIF mesurant l'évolution de la transmittance d'une feuille de polystyrène irradiée par une impulsion laser. Les résultats obtenus ont montré une bonne corrélation entre les simulations et les mesures expérimentales, confirmant ainsi la validité du nouveau modèle couplé. Ce modèle a ensuite été utilisé pour étudier les effets potentiels de l'état solide initial sur les simulations de FCI en attaque directe. Les résultats ont révélé que la prise en compte de la transition solide-plasma influence la croissance des instabilités hydrodynamiques. Nous avons observé une réduction des instabilités de basse fréquence spatiale pour des cibles possédant un ablateur épais, et une augmentation générale des instabilités de haute fréquence spatiale due à la non-linéarité du phénomène de transition solide-plasma
Direct drive inertial confinement fusion (ICF) is a method considered for achieving nuclear fusion reactions by irradiating a target with multiple high-intensity laser pulses. This target is a sphere made of a solid material called an ablator (usually polystyrene), which surrounds a fusion fuel (usually cryogenic deuterium-tritium (DT)). The energy delivered by the laser irradiation causes the ejection of the ablator and the implosion of the target due to the rocket effect. The mechanical work exerted on the hotspot (the center of the target) during the implosion is expected to trigger fusion reactions. Currently, the radiative hydrodynamic codes used to simulate ICF implosions generally assume that the ablator is initially in a plasma state, although it is actually in a solid state. This solid state could play a role during the initial interaction between the lasers and the target. Due to the initial transparency of the ablator, the laser can penetrate the target, leading to the "shine-through" effect, which can modify the laser energy deposition and potentially alter the dynamics of the shocks propagating within the target. Additionally, changes in the laser imprint can influence the evolution of hydrodynamic instabilities during the implosion.The objective of this thesis is to develop a solid-to-plasma transition model for polystyrene based on existing models, that can be integrated into hydrodynamic simulation codes for ICF. To achieve this, the model needed to be adapted to the specific constraints of these codes, taking into account the dependencies of the model on the evolution of all hydrodynamic quantities, and optimizing the numerical costs to avoid an excessive increase in simulation time. The integration of these modifications required experimental validation of the model, which was carried out through an experiment on the GCLT laser at CEA-DIF, measuring the evolution of the transmittance of a polystyrene sheet irradiated by a laser pulse. The results showed a good correlation between simulations and experimental measurements, confirming the validity of the new coupled model. This model was then used to study the potential effects of the initial solid state on direct drive ICF simulations. The results revealed that accounting for the solid-to-plasma transition influences the growth of hydrodynamic instabilities. Specifically, we observed a reduction in low spatial frequency instabilities for targets with a thick ablator, and a general increase in high spatial frequency instabilities due to the non-linearity of the solid-to-plasma transition phenomenon

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Chapitres de livres sur le sujet "Solid-to-plasma transition"

Grimes, M. K., Y. S. Lee et M. C. Downer. « Solid to Plasma Transition in Fs-Laser-Irradiated Fe : Collapse of the Spin-Orbit Gap ». Dans Applications of High-Field and Short Wavelength Sources, 131–34. Boston, MA : Springer US, 1998. http://dx.doi.org/10.1007/978-1-4757-9241-6_20.

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Grimes, Mikal K., Yun-Shik Lee et Michael C. Downer. « Vacuum Heating vs. Resonance Absorption in the Solid to Plasma Transition of fs-Laser-Irradiated Iron and Aluminum ». Dans Springer Series in Chemical Physics, 398–400. Berlin, Heidelberg : Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-72289-9_119.

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Actes de conférences sur le sujet "Solid-to-plasma transition"

Tsui, Y. Y., A. Ng, Z. Chen, M. Z. Mo, S. H. Glenzer, V. Recoules et L. Soulard. « Ultrashort Laser Generated Warm Dense Matter - Transition from Solid to Plasma ». Dans 2020 IEEE International Conference on Plasma Science (ICOPS). IEEE, 2020. http://dx.doi.org/10.1109/icops37625.2020.9717870.

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Grimes, M. K., Y. S. Lee et M. C. Downer. « Solid to Plasma Transition in fs-Laser-Irradiated Fe : Collapse of the Spin-Orbit Gap ». Dans Applications of High Field and Short Wavelength Sources. Washington, D.C. : Optica Publishing Group, 1997. http://dx.doi.org/10.1364/hfsw.1997.the33.

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Quantitative measurements of the optical conductivity of iron under earth core conditions are important in modelling geomagnetism[1]. We approximate such conditions transiently[2] by exciting an Fe, and a control Al, surface in a vacuum or helium environment with 620 nm, 120 fs FWHM laser pulses with 105 peak-background contrast ratio at .6 ps focussed to peak intensities 1011 < I < 1015 W/cm2 on target. Figs. 1 and 2 present p- and s- polarized self-reflectivity R p,s (θ,I) for constant incident angle θ and peak intensity I, respectively. Geometric correction for the dependence of spot shape on θ has been made in plotting the data. Using very linear pulse energy reference monitors, reproducibility to within ΔR/R ≤ 0.1% was achieved. This allowed measurement of very slight reflectivity changes, as shown in the inset of Fig. 1. This figure also shows that the reflectivities of Fe and Al in the solid to plasma transition region (1013 – 1015 W/cm2) approach each other as I increases, consistent with their similar total conduction electron densities (ne ≃ 1.8 × 1023 cm−3) when the Fe d-electrons are included. This suggests qualitatively that progressive unbinding of the d-electrons dominates the changes in optical properties of Fe in this regime. Fig. 2 provides evidence that a density gradient develops during the laser pulse. It is well known[3] that θ min , the angle at which the minumum p-polarized reflectivity occurs, shifts toward smaller angles as the density gradient scale length grows. Although the largest angle of incidence attainable in the experiment was smaller than θ min under these conditions, the data clearly indicate a shift toward smaller values, seen for Fe in Fig. 2 as a crossing of the p-polarized data sets.

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Sheshadri, Karthik, M. N. Manas, Shruti Raj, Narasimhaiah Ramesh et T. S. Sheshadri. « An analytical formulation of the copper load solid to plasma transition problem when driven by a pulse forming network ». Dans 2012 16th International Symposium on Electromagnetic Launch Technology (EML). IEEE, 2012. http://dx.doi.org/10.1109/eml.2012.6325052.

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Mulser, P., A. Al-Khateeb, D. Bauer, M. Hahn, D. Lewien, H. Ruhl et A. Saemann. « Scenarios of superintense fs laser pulses interacting with solids ». Dans High Resolution Fourier Transform Spectroscopy. Washington, D.C. : Optica Publishing Group, 1994. http://dx.doi.org/10.1364/hrfts.1994.md5.

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When a superintense laser pulse inpinges on a solid the target is rapidly transformed into a ’’hot solid” followed by the transition to a hot dense plasma layer. In the presentation possible scenarios of such transitions are presented for laser irradiances ranging from I = 1016 Wcm-2 μm2 to I ≃ 1018 Wcm-2 μm2.

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Garbiec, Dariusz, Maria Wiśniewska, Mateusz Marczewski, Tomasz Mościcki, Rafał Psiuk, Justyna Chrzanowska-Giżyńska, Agnieszka Krawczyńska, Bogusława Adamczyk-Cieślak et Małgorzata Lewandowska. « Spark Plasma Sintering Of Tungsten Boride With Transition Metals Admixture ». Dans World Powder Metallurgy 2022 Congress & Exhibition. EPMA, 2022. http://dx.doi.org/10.59499/wp225371814.

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To enhance the properties of tungsten diboride, solid solutions of this ceramic with transition metals such as titanium, zirconium, and tantalum were synthesized by spark plasma sintering from the pure elements. The metallic content was in all cases 24 at.%. The specimens were characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy for microstructure analysis, X-ray diffraction for phase identification as well as measurements of density and electrical conductivity. Based on the analysis of sintering curves, two stages of reactive spark plasma sintering were observed. For instance, in the W0.76Ta0.24B2 sputtering target, the WB2 and TaB2 phases were synthesized. The density changes along the diameter from 8.99 in the center to 8.29 g|cm3 on the border of the disc. The usable properties of the obtained materials mean that W-TM-B compounds may be used such as sputtering targets for high-power impulse magnetron sputtering.

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Nickles, P. V., V. N. Shlyaptsev, M. P. Kalachnikov, M. Schnuerer, T. Schlegel et W. Sandner. « Dual pulse pumping of efficient, short pulse table top X-ray lasers ». Dans International Conference on Ultrafast Phenomena. Washington, D.C. : Optica Publishing Group, 1996. http://dx.doi.org/10.1364/up.1996.tue.11.

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We report on the first realization of efficient x-ray lasers using transient gain in collisionally excited neon-like ions. These lasers are working on a double pulse excitation scheme proposed by us in 1993 [1] for solid and foil targets.In a first step, a long ns- pump pulse produces a plasma column of the desired neon-like ions with both a uniform electron density and temperature.The second but short ps- pump pulse arrives at the preformed plasma after a certain delay and heats it up very rapidly, producing very efficiently a transient gain. Lasing was experimentally realized on the 3p-3s transitions in Titanium XII at 32.6 nm, as well as in Vanadium XIV at 30.4 nm. Additionally, in Ti a bright lasing line at 29.8 nm was recorded, which is supposed to result from a photo pumped 3d-3p transition.

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Smirnova, K. V., D. A. Shutov, A. N. Ivanov et V. V. Rybkin. « Plasma-solution synthesis of a solid phase from solutions of iron and cobalt nitrates of various concentrations ». Dans 8th International Congress on Energy Fluxes and Radiation Effects. Crossref, 2022. http://dx.doi.org/10.56761/efre2022.n1-o-046701.

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The solution of the fundamental problem of the physicochemical interaction of plasma with solutions of transition metal salts has practical applications in the field of creating new materials and purifying water from heavy metal ions. Plasma-solution synthesis has established itself as a simple and effective method for obtaining ultrafine materials with new properties. The formation of precipitation under the action of atmospheric pressure glow discharge on an iron and cobalt nitrates solution, which was the anode, was studied. It turned out that the rate of formation increases with an increase in the discharge current from 30 to 70 mA. In the course of work, the concentrations of nitrates were varied. The concentrations were chosen in such a way that the final product was stoichiometric Fe2O3·CoO. The result of the study of kinetic regularities indicates that the sedimentation of the solid phase from nitrate solutions occurs in two stages. The first is the precipitation of particles containing iron anions; the second capture is the precipitation of cobalt-containing particles.

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Barber, David, H. A. Calderón, Julio Quintero et Francisco C. Robles Hernandez. « Synthesis of Carbon Nanostructures by Thermo-Mechanical Means ». Dans ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-89866.

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Different C phases have been developed by mechanical milling, conventional heat treatments and Spark Plasma Sintering of C soot and transition metals (Fe or Ni). Transition metals are known to catalyze the development of different C phases. The energy input involved in such a processing method has been used to develop composite and ceramic materials made of transition metals and fullerenes and C soot. The as milled samples as well as the sintered composites show various dispersions of diamonds, fullerenes, carbon nanotubes, graphitic carbon, graphenes, among other nanostructures. Thus milling, heat treatment or sintering of quasi-amorphous carbon nanostructures with different transition metals under various conditions can be a simple route to synthesize the above mentioned phases in solid state. Results of electron (scanning and transmission) microscopy, Raman spectroscopy, XRD and nanohardness are presented and discussed accordingly.

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Torrell, M., I. G. Cano, J. M. Miguel, J. M. Guilemany, M. A. Laguna-Bercero et V. M. Orera. « Solid Oxide Fuel Cells Produced by Atmospheric Plasma Spray Technology : Structural and Electrochemical Characterization ». Dans ITSC 2012, sous la direction de R. S. Lima, A. Agarwal, M. M. Hyland, Y. C. Lau, C. J. Li, A. McDonald et F. L. Toma. ASM International, 2012. http://dx.doi.org/10.31399/asm.cp.itsc2012p0627.

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Abstract The use of ceramic materials in the production of solid oxide fuel cells (SOFCs) is one of the most innovative applications of these materials in recent years. The aim of this work is to assess how to obtain a complete, self-assembled SOFC (supported by electrolyte) using atmospheric plasma spray (APS) to spray the three different ceramic layers of the assembly. One of the main problems of SOFC production is the high cost of the process; the hypothesis is that these costs can be reduced by forming the three ceramic layers of the SOFC by APS technology. The anode (YSZ-NiO), cathode (LSM), and electrolyte (YSZ) layers can be produced by APS with reasonable efficiency. Another problem with SOFC manufacture is assembly and adhesion of the three layers; the creation of gradual transition layers by APS improves these aspects of the production process. Chemical and structural characterization of the feedstock powders and resultant ceramic layers was performed by laser scattering, XRD, SEM, and confocal microscopy, and the results confirmed the efficiency of the attained APS-SOFC components.

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Luk, T. S., McPherson, D. Tate, K. Boyer, C. K. Rhodes, V. L. Jacobs, P. G. Burkhalter, A. Zigler, D. A. Newman et D. J. Nagel. « X-Ray Spectral Determination of Electron Density in Dense Laser-Excited Targets* ». Dans Short Wavelength Coherent Radiation : Generation and Applications. Washington, D.C. : Optica Publishing Group, 1991. http://dx.doi.org/10.1364/swcr.1991.tua1.

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Plasmas produced by subpicosecond laser excitation of solid targets can produce bright short x-ray pulses[1] for x-ray laser pumping[2]. This type of plasma is unusual because it is hot (electron temperature in keV range), dense (near solid density) and highly non-equilibrium. It is particularly advantageous to use subpicosecond excitation to investigate this type of plasma, since expansion of the plasma can be quite small under this condition. Furthermore, it has been found that the prepulse associated with typical high-power ultraviolet laser systems does not Interfere with the subpicosecond excitation for ultraviolet transmitting solids, such as MgF2 and SiO2. This follows, since the intensity for appreciable absorption is roughly five orders of magnitude higher than the intensity associated with the laser prepulse. Also for laser radiation with wavelength of 248 nm, the critical density is 1.8 × 1022 cm−2, only a factor of 44 lower than the electron density of a completely stripped MgF2 solid target. Therefore, the laser radiation naturally interacts with a plasma of very high density. Finally, x-ray spectroscopy is particularly useful for diagnosing the conditions of the plasma for very short time intervals that are considerably outside of the range available for conventional streak-camera measurements. Since typical radiative lifetimes for kilovolt transitions are of the order of 100 fs, the emitted radiation can provide valuable information in the early hlgh-density phase of the plasma. In this experiment, we examine the dielectronic satellite from lithium-like ions in order to determine the electron density of the plasma.

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