Academic literature on the topic 'Nitrogen afterglow'
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Journal articles on the topic "Nitrogen afterglow"
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Tálský, A., O. Štec, M. Pazderka, and V. Kudrle. "Kinetic Study of Atmospheric Pressure Nitrogen Plasma Afterglow Using Quantitative Electron Spin Resonance Spectroscopy." Journal of Spectroscopy 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/5473874.
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Quantitative electron spin resonance spectroscopy is used to measure nitrogen atom density in atmospheric pressure dielectric barrier discharge afterglow. The experiment shows that oxygen injection into early afterglow increases the nitrogen dissociation in certain parts of the afterglow while it is decreased in the rest of the afterglow. Numerical kinetic modelling supports and explains the experimental data while the best fit provides some a priori unknown parameters such as initial concentrations and rate constants.
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Amorim, J., and V. Kiohara. "N(2D) in nitrogen afterglow." Chemical Physics Letters 385, no. 3-4 (February 2004): 268–72. http://dx.doi.org/10.1016/j.cplett.2003.12.101.
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Kolar, Metod, and Gregor Primc. "Haemostatic Response of Polyethylene Terephthalate Treated by Oxygen and Nitrogen Plasma Afterglows." International Journal of Polymer Science 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/1749285.
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Samples of polymer polyethylene terephthalate were coated with heparin and the haemostatic response has been determined by optical imaging of samples after incubation with fresh blood from a healthy donor. Prior to coating the samples were treated by neutral reactive particles of the oxygen or nitrogen plasma flowing afterglow. X-ray photoelectron spectroscopy analysis showed intensive functionalization of the polymer foils upon treatment with afterglows; however, the concentration of sulphur from heparin remained below the detection limit. The optical imaging showed densely distributed blood platelets in highly activated forms on untreated samples, whereas treatment with both afterglows revealed improved hemocompatibility. Best results were obtained for oxygen-functionalized polymer, whereas additional coating with heparin caused moderate loss of hemocompatibility, that was explained by deactivation of surface functional groups upon incubation with heparin.
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Guerra, Vasco, Paulo A. Sá, and Jorge Loureiro. "Nitrogen pink afterglow: the mystery continues." Journal of Physics: Conference Series 63 (April 1, 2007): 012007. http://dx.doi.org/10.1088/1742-6596/63/1/012007.
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Krčma, F., and M. Žáková. "Pink afterglow in nitrogen-argon mixtures." European Physical Journal D 54, no. 2 (May 8, 2009): 369–75. http://dx.doi.org/10.1140/epjd/e2009-00147-0.
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Zivanovic, Emilija. "Investigation of the effect of additional electrons originating from the ultraviolet radiation on the nitrogen memory effect." Facta universitatis - series: Electronics and Energetics 28, no. 3 (2015): 423–37. http://dx.doi.org/10.2298/fuee1503423z.
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The influence of ultraviolet radiation on memory effect in nitrogen has been investigated. The spectrum of the radiation which passes through the walls of the experimental sample was obtained by the spectrometer. A detailed comparison of experimental results of electrical breakdown time delay as a function of afterglow period with and without ultraviolet irradiation was performed. These studies were done for such product of gas pressure and inter-electrode distance when both breakdown initiation mechanisms exist. The research has shown that ultraviolet radiation leads to the decrease in ion concentration in early nitrogen afterglow due to recombination of nitrogen ions with electrons released from the tube walls and electrodes. Meanwhile, it has been cofirmed that this radiation has a negligible influence on the breakdown initiation in late nitrogen afterglow when a significant nitogen atom concentration is persistent. When the concentration of nitrogen atoms decreases enough, the breakdown initiation is caused by cosmic rays but UV photons have an important influence because of the rise of the electron yield.
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Piper, Lawrence G. "Further observations on the nitrogen orange afterglow." Journal of Chemical Physics 101, no. 12 (December 15, 1994): 10229–36. http://dx.doi.org/10.1063/1.467903.
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Janča, J., A. Tálský, and F. Krčma. "Recombination in nitrogen afterglow at low temperatures." Czechoslovak Journal of Physics 43, no. 12 (December 1993): 1213–21. http://dx.doi.org/10.1007/bf01590189.
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Markovic, Vidosav, Sasa Gocic, and Suzana Stamenkovic. "Homogeneous gas phase models of relaxation kinetics in neon afterglow." Facta universitatis - series: Physics, Chemistry and Technology 5, no. 1 (2007): 33–44. http://dx.doi.org/10.2298/fupct0701033m.
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The homogeneous gas phase models of relaxation kinetics (application of the gas phase effective coefficients to represent surface losses) are applied for the study of charged and neutral active particles decay in neon afterglow. The experimental data obtained by the breakdown time delay measurements as a function of the relaxation time td (?) (memory curve) is modeled in early, as well as in late afterglow. The number density decay of metastable states can explain neither the early, nor the late afterglow kinetics (memory effect), because their effective lifetimes are of the order of milliseconds and are determined by numerous collision quenching processes. The afterglow kinetics up to hundreds of milliseconds is dominated by the decay of molecular neon Ne2 + and nitrogen ions N2 + (present as impurities) and the approximate value of N2 + ambipolar diffusion coefficient is determined. After the charged particle decay, the secondary emitted electrons from the surface catalyzed excitation of nitrogen atoms on the cathode determine the breakdown time delay down to the cosmic rays and natural radioactivity level. Due to the neglecting of number density spatial profiles, the homogeneous gas phase models give only the approximate values of the corresponding coefficients, but reproduce correctly other characteristics of afterglow kinetics from simple fits to the experimental data.
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Legrand, J. C., A. M. Diamy, R. Hrach, and V. Hrachová. "Mechanisms of methane decomposition in nitrogen afterglow plasma." Vacuum 52, no. 1-2 (January 1999): 27–32. http://dx.doi.org/10.1016/s0042-207x(98)00208-5.
Full textDissertations / Theses on the topic "Nitrogen afterglow"
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Lepikhin, Nikita. "Fast energy relaxation in the afterglow of a nanosecond capillary discharge in nitrogen/oxygen mixtures." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX087/document.
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L'objectif principal du présent travail était d'étudier, comment la cinétique du plasma change dans les conditions de dépôt d'énergie spécifique élevé dans des champs électriques réduits élevé. La décharge capillaire nanoseconde a été utilisée comme outil expérimental. Les mesures sont effectuées dans l'azote pur et dans les mélanges azote/oxygène. Les paramètres électriques de la décharge sont mesurés: la tension appliquée, le dépôt d'énergie, le champ électrique et le courant électrique. Les spectres de l'émission optique de la décharge sont obtenus. La densité électronique dans les impulsions de décharge est mesurée. La décroissance du plasma est étudiée par les mesures de la densité électronique dans la post‐luminescence de la décharge. Les processus contrôlant la décroissance du plasma sont déterminés. La dépopulation de molécules excitées sur l'exemple de l'azote moléculaire N2(C) est étudié dans des mélanges azote/oxygène. Les processus responsables de la dépopulation des espèces excitées lors de la post‐luminescence de la décharge de nanoseconde à les conditions de dépôt d'énergie spécifique élevé dans des champs électriques réduits élevé sont examinés. La distribution radiale des espèces excitées à différentes compositions de gaz sont étudiée et comparées. L'étude expérimentale et numérique des processus responsables du chauffage rapide du gaz dans l'azote pur et dans les mélanges azote/oxygène dans la post‐luminescence de la décharge capillaire à la nanoseconde sont effectuées. Les particularités du chauffage rapide du gaz aux conditions de la décharge de nanoseconde à de dépôt d'énergie spécifique élevé dans des champs électriques réduits élevé sont étudués. La modification du schéma cinétique actuellement utilisé est proposéeThe main aim of the present work was to investigate, how the plasma kinetics changes at the conditions of high specific energy deposition at high reduced electric fields. The nanosecond capillary discharge was used as an experimental tool. The measurements are performed for pure nitrogen and nitrogen/oxygen mixtures. Electric parameters of the discharge are measured: the applied voltage, the energy deposition, the electric field, and the electric current. The spectra of the optical emission of the discharge are obtained. The electron density in the discharge pulses is measured. The plasma decay is studied by the measurements of the electron density in the afterglow of the discharge as well. The processes controlling the plasma decay are determined. Depopulation of excited molecules on the example of N2(C) state of molecular nitrogen is studied in nitrogen/oxygen mixtures. The processes responsible for depopulation of excited species in the afterglow of the nanosecond discharge at high specific deposited energy at high reduced electric field are discussed. The radial distributions of the excited species at different gas compositions are investigated and compared. The experimental and numerical studies of the processes responsible for fast gas heating in pure nitrogen and in nitrogen/oxygen mixtures in the afterglow of nanosecond capillary discharge are performed. The peculiarities of the fast gas heating at conditions of the nanosecond discharge at high specific deposited energy at high reduced electric field are discussed. The modification of the kinetic scheme currently in use is proposed
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Žáková, Marie. "Optická emisní spektroskopie dohasínajícího plazmatu ve směsi dusík-argon." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-216566.
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The study of plasmas generated in pure nitrogen and their afterglows are a subject of many hundreds works bringing a lot of information about the kinetic processes and energy transfer reactions. The effect of nitrogen pink afterglow has a specific position among the other kinds of discharges and post-discharges. The post-discharge, and especially the pink afterglow, is extremely sensitive to the presence of various impurities and experimental conditions (total gas pressure in a discharge tube, temperature, etc.) because of their significant influence on all kinetic processes. That is the reason, why it is so important to study this processes. The DC flowing afterglow (generated using the hollow molybdenum electrodes in the distance of 12 cm, power ± 290 W) was used for the experimental part of this work. The discharge was created in Pyrex discharge tube at different concentration ratio of nitrogen and argon. The total gas presure was in range from 500 Pa to 5000 Pa. The emission spectra of post-discharge were recorded by TRIAX 550 spectrometer with CCD detector in the range of 320-780 nm. The vibrational populations at individual vibrational levels were calculated using the emission bands of the first (N2 (B 3g) N2 (A 3u+)) and the second (N2 (C 3u) N2 (B 3g)) positive and the first negative (N2+ (B 2u+) N2+ (X 2g+) nitrogen spectral systems. The dependencies of intensity on decay time and relative vibrational populations on argon concentration and pressure were obtained. The pink afterglow was very sharp in pure nitrogen at low pressure. With the increasing total pressure it was shifted to the later decay times and it was visible for longer time, too. The same effect was observed with the increase of argon concentration in the gas mixture. At the highest argon concentrations, especially at lower pressure, the effect of pink afterglow dissapeared. The knowledge of these processes can give the solution of all kinetic reactions in plasma and this can be used in plasma chemistry and for development of new technologies. This will be a subject of further intensive studies.
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Teslíková, Ivana. "Studium dohasínajícího dusíkového plazmatu pomocí titrace rtuťových par." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2012. http://www.nusl.cz/ntk/nusl-216820.
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The aim of this master thesis is a study of nitrogen post-discharge by mercury vapours titration. The nitrogen post-discharge is investigated for many years theoretically as well as for a practical use. The object of this master thesis is a study of kinetic processes ongoing at titrations of mercury vapours during the nitrogen post-discharge at different pressures and applied powers. All experimental data were obtained from an optical emission spectroscopy of nitrogen post-discharge. DC discharge in flowing regime was chosen for measurements. The first part of experiments was carried out at the constant discharge current (100 mA), voltage (1300 V) and wall temperature (300 K). The total gas pressure was varied in range of 500-3000 Pa at nitrogen flow in range of 0.12-0.68 l/min. Nitrogen flow values were arranged to obtain constant nitrogen flow velocity for all gas pressures. The second set of experiments studied power dependencies. The current was varied in the range of 50-200 mA for constant voltage 1300 V. The total gas pressure in this case was 1000 Pa. Mercury vapours were introduced into the system by titration tube at different post-discharge time. The nitrogen pink afterglow effect was well visible at all experimental conditions. This effect corresponds to the maximum intensity of light emission, which expresses as considerable growth of characteristic pink radiation in the post-discharge time. Optical emission spectra of post-discharge were taken in the range of 320-780 nm. Besides three nitrogen spectral systems (first and second positive and first negative), the mercury line at 254 nm was recorded in the second order spectrum at 508 nm under these conditions if mercury was added. This spectral line is excited under post-discharge conditions by collisionally induced resonance energy transfer from nitrogen highly vibrationally excited ground state metastables and it opens an unique technique for their monitoring. The dependence of relative intensities on decay time for mercury spectral line and selected nitrogen spectral systems at different titration positions were measured. The relative intensities of nitrogen bands decrease with increasing of mercury line relative intensity for all total gas pressures. The pink afterglow phenomenon shifts to the later decay times with the increasing of total gas pressure. In the case of experiments at different power, it can be seen that with decreasing power mercury spectral line intensity decreases in post-discharge time. The first detailed tests of the unique detection for highly excited of nitrogen metastables were completed. However this master thesis is concentrated on the basic research which supports better indication of kinetic processes and reactions leading to transformation of excitation energy, this new knowledge should be applied in future also in technologies based on the long-lived metastable induced reactions.
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Soural, Ivo. "Studium procesů v dohasínajícím plazmatu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-233321.
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The decaying plasma was studied by the optical emission spectroscopy. DC discharge created at 45 – 200 mA in Pyrex and Quartz tubes in flowing regime was used. The emission of three nitrogen spectral systems (1st and 2nd positive and 1st negative) were studied in time evolution for pressures of 500 – 5 000 Pa at two wall temperatures – ambient and liquid nitrogen (150 K inside the decaying plasma). Results showed that all three nitrogen systems (respectively N2(B, v), N2(C, v) and N2+(B, v) states as their origins) had their population maxima called pink-afterglow in the afterglow part. These maxima decreased with the increase of pressure for all systems, and moved to the later decay time. Maxima increased with discharge current (respectively power) and moved to shorter time. Populations at temperature of 150 K were measured due to the experimental arrangement from 17 ms, only, and thus pink aftergow maximum wasn’t observed (only at 5 000 Pa some maximum was recognized). Populations were smaller at 150 K that populations measured at laboratory temperature at the middle decay time (50-100 ms). At the late time, the populations were higher at lower temperature at lower pressure. Higher shifts (in intensity and decaytime) of pink afterglow maxima were observed in Quartz tube in comparison with their values in Pyrex tube. Besides the populations, rotational temperatures of selected bands of three observed spetral systems (for 1st negative 0-0 band, 1st positive 2-0 band and for 2nd positive 0-2 band) were measured. Rotational temperatures were monitored from presumption that this kind of temperature is equal to temperature of neutral gas (at local thermodynamic equilibrium). Results from 1st negative and 1st positive system showed strong decreasing of rotational temperatures up to about 10 ms at post-discharge begin, then temperatures were constant up to 20 ms of decay time and after that they grew up. Temperatures increased with the increase of current. The part with decreased temperature correlated with pink-afterglow part of post-discharge. Unfortunately, rotational temperatures of 2nd positive system had bad reproducibility and the time profile shape was opposite. Experimental results were compared with numerical kinetic model created by group of prof. Vasco Guerra at Instituto Supetior Técnico in Portugal. Several sets of conditions for simulation at 500 and 1 000 K in active discharge were applicable for the calculation corresponding to the experiment. Comparison of numerical simulation and experimental data done for N2(B) state demonstrated that maxima populations in pink afterglow are depended on the temperature difference between active discharge and post discharge. Maxima populations were supposed in pink afterglow disappeared if the same temperatures in active and post discharges were supposed. Temperature in active discharge is higher at higher apllied power, as it was showed from rotational temperatures observation. The results clearly showed that real temperature profile must be included into the kinetic model.
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Gueye, Magamou. "Caractérisation par infrarouge à transformée de Fourier des réactions chimiques entre post-décharges et précurseurs organosiliciés : cas du 3-aminopropyltriethoxysilane (APTES)." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0020/document.
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Les travaux présentés dans ce mémoire concernent la caractérisation par infrarouge à transformée de Fourier (FTIR) et par spectroscopie d’émission optique (SEO) des réactions chimiques entre post-décharges et précurseurs organosiliciés, avec comme exemple le cas du 3-aminopropyltriéthoxysilane (APTES). Le but est d’obtenir la rétention la plus élevée possible de fonctions amine -NH2 dans les revêtements ou dans les nanoparticules synthétisées. Tout d’abord, un état de l’art des post-décharges Ar-N2 et Ar-O2 et leurs applications est présenté ainsi que la cinétique d’interaction de l’APTES dans ces post-décharges, mettant en évidence le rôle des mélanges plasmagènes sur la décomposition du précurseur et sur la nature des films déposés. Ensuite l’étude de la décomposition de l’APTES dans une post-décharge Ar-N2 est réalisée. Les analyses par SEO et par FTIR in situ montrent le rôle des atomes d’azote N dans la formation des différents sous-produits, à savoir HCN, CO et C=O. Les nanoparticules synthétisées contiennent peu d’amine primaire, et présentent une concentration non négligeable d’azote sous forme d’amide secondaire. Dans le cas de l’étude de la décomposition de l’APTES dans la post-décharge Ar-O2 en mode pulsé, une tendance se dessine : les nanoparticules synthétisées en phase gazeuse lorsque les rapports cycliques augmentent ont une composition qui s’appauvrit en azote et en carbone mais s’enrichit en oxygène. Les groupements NH2 initiaux sont fortement convertis en groupement amide. Les nanoparticules synthétisées avec des rapports cycliques élevés ont des compositions différentes de celles des films minces déposés sur les parois, plus proches de la silice et ce en raison de la gravure par l’oxygène atomique qui les affecte davantage. Le comportement spécifique des atomes d’oxygène et d’azote en post-décharge rend difficile la rétention des amines dans les polymères plasmas. Enfin nous avons terminé par une étude de l’hydrodynamique dans le cas de l’interaction entre l’acétylène et une post-décharge Ar-O2 et établi l’importance de l’écoulement sur toute approche visant à faire des mesures FTIR résolues temporellementThe present work deals with the characterization by Fourier transform infrared spectroscopy (FTIR) and by optical emission spectroscopy of chemical reactions between a post-discharge and an organosilicon precursor: the 3-aminopropyltriethoxysilane (APTES). The aim is to keep the highest retention of amine functions -NH2 in coatings or in the synthesized nanoparticles. First, a state of the art of Ar-N2 and Ar-O2 post-discharges and their applications is presented as well as the kinetics of the interaction of APTES in these post-discharges, highlighting the role plasma gases on the decomposition of the precursor and the nature of the deposited films. Then, the study of the decomposition of APTES in an Ar-N2 post-discharge is carried out. Analysis by optical emission spectroscopy (OES) and in situ FTIR show the role of the nitrogen atoms N in the formation of various main by-products, namely HCN, CO and C=O. The synthesized nanoparticles contain few primary amines, and have a significant concentration of nitrogen in the form of secondary amide. In the case of interaction APTES with pulsed Ar-O2 afterglow, there is one main trend: the nanoparticles synthesized in the gas phase when the duty cycle increases have a composition that decreases in nitrogen and carbon but increases in oxygen. The -NH2 groups are efficiently converted into amide groups. The nanoparticles synthesized with high duty cycle exhibit compositions that are different from those of thin films deposited on the walls, the latter being close to silica because of the etching by atomic oxygen, which affects them more. The specific behavior of oxygen and nitrogen atoms in post-discharge makes difficult the retention of a high level of amines in plasma polymers. Finally, we finished with a study of the hydrodynamics in the case of the interaction of acetylene with an Ar-O2 post-discharge and proved the key role of the flow for any approach aiming at getting time-resolved FTIR measurements
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Mazánková, Věra. "Spektroskopické studium dohasínajících výbojů v dusíku a jeho směsích." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-233291.
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Presented thesis gives results obtained during the spectroscopic observations of post –discharges of the pure nitrogen plasma with small oxygen admixture and in the nitrogen – argon mixture and the effect of the pink afterglow in it. The DC discharge in the flowing regime has been used for the plasma generation. The decaying plasma was study by optical emission spectroscopy, mainly in the range of 300–800 nm. The first positive, second positive, first negative nitrogen spectral system and NO spectral systems were observed in measured spectra. The band head intensities of these bands have been studied in the dependencies on experimental conditions. Simultaneously, the relative vibrational populations on the given nitrogen states have been calculated. Two discharge tubes made from different materials (PYREX glass and QUARTZ glass) were used in the case of nitrogen plasma containing low oxygen traces (up to 0.2 %). These experiments have been carried out at two wall temperatures for the determination of the temperature effect on the post-discharge. The discharge tube around the observation point was kept at the ambient temperature (300 K) or it was cooled down to 77 K by liquid nitrogen vapor. The total gas pressure of 1 000 Pa and the discharge current of 200 mA were conserved for all these experiments. The relative populations of electronic states were calculated in the dependence on the post-discharge time. The dependencies on oxygen concentration were given, too. The results showed no simple dependence of vibrational populations on oxygen concentration. Generally, slight increase of neutral nitrogen states populations was observed with the increase of oxygen concentration. These observations were well visible due to the intensity of nitrogen pink afterglow effect that was well visible at all oxygen concentrations. The pink afterglow maximal intensity was reached at about 5–10 ms at the wall temperature of 300 K in the PYREX tube. The molecular ion emission was strongly quenched by the oxygen and as this was dominant process for the pink afterglow emission the pink afterglow effect disappears at oxygen concentration of about 2000 ppm. The temperature and wall material influences were observed, too. The post-discharge in nitrogen argon mixtures was studied only in the PYREX tube at the ambient wall temperature of 300 K. The power dissipated in an active discharge was constant of 290 kW. The experimental studies had two new parameters – total gas pressure (500 Pa – 5 000 Pa) and the argon concentrations that were varied in the range of 0–83 %. Also in this case the dependencies of relative intensities of the bands given above were obtained and further the relative populations of electronic states as a function of decay time, total gas pressure and on argon concentration were obtained. The pink afterglow effect was observed at all applied discharge powers and total gas pressures. At the highest argon concentrations, especially at lower pressure, the pink afterglow effect disappeared. The presented experimental work is one of the hugest sets of experiments in the nitrogen with oxygen traces and in nitrogen-argon mixtures. These data can be used as a very good fundament for the further studies using wide numeric modeling of the post-discharge kinetic processes.
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Quichaud, Viviane. "Etude des processus elementaires : de synthese de la molecule no, en post-decharge en ecoulement, de collisions titane-gaz rares, titane-molecules, par perturbation laser resolue en temps." Paris 6, 1987. http://www.theses.fr/1987PA066135.
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I. Etude de la preparation des etats excites de no dans un dispositif de post-decharge en ecoulement a partir de n::(2) excite (prepare par transfert d'excitation a partir d'atomes ar metastables dans une decharge basse pression) et de o (obtenu par dissociation de o::(2) dans une decharge de he). Observation d'une emission intense des bandes gamma de no, qui implique un etat a courte duree de vie (b) de n::(2) et le premier etat metastable de o. Ii. Analyse des processus d'extinction et de transfert d'excitation a partir d'etats a courte duree de vie de ti (crees dans un dispositif a cathode creuse) lors de collisions avec des gaz rares (ar, ne, he) et des molecules (n::(2),h::(2)). Ces experiences permettent l'etude de cinetiques de reactions elementaires au sein d'un plasma basse pression ensemence de vapeurs metalliques, a l'aide du dispositif de post-decharge en ecoulement
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Robert, Bigras Germain. "Modification de films de graphène dans la post-décharge en flux de plasmas micro-ondes d’azote à pression réduite." Thesis, 2020. http://hdl.handle.net/1866/25251.
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Ce projet de thèse porte sur le traitement de films de graphène dans la post-décharge en flux de plasmas micro-ondes d’azote à pression réduite. Différentes considérations de contamination de surface des échantillons se sont avérées cruciales pour ce travail. Par exemple, en présence d’hydrocarbures, les traitements dans les différentes régions de la post-décharge montrent des profils de production de dommages, d’incorporation d’azote et de fonctionnalisation de contaminants distincts. Le traitement agressif qu’offre la post-décharge proche résulte en la formation de complexes amorphes graphène-hydrocarbures responsables d’une forte hausse de la teneur en azote (jusqu’à 49%) pour des désordres modérés (D:G = 1.3). Pour les traitements dans la post-décharge lointaine, les hydrocarbures jouent un rôle de couche protectrice permettant une incorporation monotone (jusqu’à 18%) à très faible dommage (D:G < 0.3). Les espèces azotées sont néanmoins faiblement liées de sorte que le transfert vers un substrat de SiO2 engendre une perte importante (> 80%) de la teneur en azote. Des considérations d’inhomogénéité de surface des films de graphène ont motivé le développement d’une nouvelle méthode d’analyse des cartographies Raman obtenues par un imageur hyperspectral. L’étude des spectres Raman au niveau des domaines versus aux joints de grains ont permis de mettre en évidence un mécanisme d’auto-réparation des joints de grains relié à l’anisotropie de la migration des adatomes de carbone en surface. L’accumulation de ceux-ci aux joints de grains mène à une émission d’adatomes responsable de l’annihilation de paires de Frenkel. Dans les plasmas azotés, il s’avère que ce mécanisme est également responsable d’une incorporation sélective d’azote aux domaines de croissance du graphène. Lorsque amorphisé, le dopage sélectif s’estompe puisque le transport des adatomes de carbone aux joints de grains, ainsi que l’accumulation essentielle au processus d’auto-réparation, deviennent entravés. Finalement, la recombinaison en surface d’atomes d’azote et la désexcitation de métastables N2(A) sont identifiés comme principaux agents pour la production de dommages dans la post-décharge en flux d’azote. Un modèle d’incorporation impliquant la formation de dommages et l’adsorption d’atomes d’azote est proposé. En présence d’espèces oxydantes dans la post-décharge d’azote, la formation de dommages demeure limitée par les populations de N et de N2(A).This thesis project deals with the treatment of graphene films in the flowing afterglow of microwave nitrogen plasmas at reduced pressure. Various surface contamination considerations were found to be crucial for this work. For example, in the presence of hydrocarbons, the treatments in the different regions of the afterglow show distinct damage production, nitrogen incorporation and contaminant functionalization profiles. The aggressive treatment offered by the early afterglow results in the formation of amorphous graphene-hydrocarbon complexes responsible for a sharp increase in the nitrogen content (up to 49%) at moderate disorders (D: G = 1.3). For the treatments in the late afterglow, the hydrocarbons act as a protective layer, allowing a monotonic incorporation (up to 18%) with very low damage (D: G < 0.3). Nitrogenous species are found to be weakly bound so that transfer to an SiO2 substrate generates a significant loss (>80%) of the nitrogen content. Considerations of surface inhomogeneity of graphene films have motivated the development of a new analysis method of Raman maps obtained by hyperspectral imager. The study of Raman spectra at growth domain versus grain boundary has revealed a self-healing mechanism of grain boundaries linked to the anisotropy of the migration of carbon adatoms at the surface. The accumulation of these at grain boundaries leads to an emission of atoms responsible for the annihilation of Frenkel pairs. In nitrogenous plasmas, this mechanism is also found to be responsible for the selective incorporation of nitrogen into the growth domains of the graphene. For amorphous graphene, selective doping fades as the transport of carbon adatoms to grain boundaries, and therefore the accumulation essential to the self-healing process, becomes impeded. Finally, the surface recombination of nitrogen atoms and the de-excitation of metastable N2(A) are identified as the main agents defect generation in the nitrogen flowing afterglow. An incorporation model involving the formation of damage and adsorption of nitrogen atoms is proposed. In the presence of oxidizing species in the nitrogen afterglow, damage formation remains limited by populations of N and N2(A).
Book chapters on the topic "Nitrogen afterglow"
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Dinescu, G., E. Aldea, D. Bivolaru, and G. Musa. "Investigation of Species in Flowing Nitrogen Afterglow by a Discharge Probe." In Molecular Physics and Hypersonic Flows, 515–24. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0267-1_34.
Full textConference papers on the topic "Nitrogen afterglow"
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Siefert, N., B. Ganguly, and P. Bletzinger. "Shockwave-Induced Enhancement of Optical Emission in Nitrogen Afterglow Plasma." In 36th AIAA Plasmadynamics and Lasers Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2005. http://dx.doi.org/10.2514/6.2005-5372.
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Kamaratos, Efstathios. "Energy transfer in a nitrogen afterglow in the presence of activated oxygen." In Medical Imaging 2003 Physiology and Function: Methods, Systems, and Applications, edited by Alexis Carabelas, Giuseppe Baldacchini, Paolo Di Lazzaro, and Dimitrios Zevgolis. SPIE, 2003. http://dx.doi.org/10.1117/12.513591.
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Lepikhin, Nikita D., Nikolay A. Popov, and Svetlana Starikovskaia. "Evolution of electronically excited nitrogen species in a nanosecond capillary discharge and in the afterglow." In 2018 AIAA Aerospace Sciences Meeting. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2018. http://dx.doi.org/10.2514/6.2018-0178.
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Razhev, A. M., D. S. Churkin, and E. S. Kargapol'tsev. "Simultaneous generation of laser radiation at 337.1 nm and Lewis-Rayleigh afterglow in inductive nitrogen laser." In 2014 International Conference Laser Optics. IEEE, 2014. http://dx.doi.org/10.1109/lo.2014.6886268.
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Lee, Jeong-Beom, Dae-Ho You, and Hong-Young Chang. "PPPS-2013: Collisional effect on the ion energy distributions outside the sheath during the afterglow of pulsed oxygen and nitrogen plasmas." In 2013 IEEE 40th International Conference on Plasma Sciences (ICOPS). IEEE, 2013. http://dx.doi.org/10.1109/plasma.2013.6633372.
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Guerra, Vasco. "Self-consistent modeling of DC and microwave nitrogen discharges and their afterglows." In THE PHYSICS OF IONIZED GASES: 22nd Summer School and International Symposium on the Physics of Ionized Gases; Invited Lectures, Topical Invited Lectures and Progress Reports. AIP, 2004. http://dx.doi.org/10.1063/1.1843497.
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