Дисертації з теми "Inductive plasma"
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1
Magin, Thierry. "A model for inductive plasma wind tunnels." Doctoral thesis, Universite Libre de Bruxelles, 2004. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211179.
Повний текст джерелаАнотація:
A numerical model for inductive plasma wind tunnels is developed. This model provides the flow conditions at the edge of a boundary layer in front of a thermal protection material placed in the plasma jet stream at the outlet of an inductive torch. The governing equations for the hydrodynamic field are derided from the kinetic theory. The electromagnetic field is deduced from the Maxwell equations. The transport properties of partially ionized and unmagnetized plasma in weak thermal nonequilibrium are derived from the Boltzmann equation. A kinetic data base of transport collision integrals is given for the Martian atmosphere. Multicomponent transport algorithms based upon Krylov subspaces are compared to mixture rules in terms of accuracy and computational cost. The composition and thermodynamic properties in local thermodynamicequilibrium are computed from the semi-classical statistical mechanics.
The electromagnetic and hydrodynamic fields of an inductive wind tunnel is presented. A total pressure measurement technique is thoroughly investigated by means of numerical simulations.
Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished
2
Rax, Jean-Marcel. "Études sur la génération non inductive de courant dans un plasma." Paris 11, 1987. http://www.theses.fr/1987PA112032.
Повний текст джерелаАнотація:
Étude détaillée de la génération de courant continu dans un plasma de fusion à l'aide d'ondes radiofréquence. Calcul des réponses du plasma à l'aide de la fonction de green de l'opérateur de collisions. Pour résoudre la partie électromagnétique, on explicite la fonction de green eikonal des équations de maxwell. Muni de ces deux outils cinétiques et électromagnétiques, on calcule les réponses principales du plasma et on compare les résultats à l'expérience petula.
3
Popelier, Lara. "Développement du propulseur PEGASES : source inductive à haute performance et accélération successive de faisceaux d'ions positifs et d'ions négatifs." Phd thesis, Ecole Polytechnique X, 2012. http://tel.archives-ouvertes.fr/tel-00793098.
Повний текст джерелаАнотація:
PEGASES est un nouveau propulseur conçu et développé au LPP. Un propulseur électrique classique éjecte de la matière positive à grande vitesse depuis un plasma électropositif pour générer la poussée. La nouveauté introduite par PEGASES est le fait que la poussée est générée par l'accélération successive d'ions positifs et d'ions négatifs issus d'un plasma ion-ion continu. Le propulseur PEGASES est composé de trois étages: (i) un étage d'ionisation constitué d'une source radiofréquence (rf) pour le couplage inductif d'un plasma électronégatif à partir d'un gaz contenant des halogènes, (ii) un étage de filtrage magnétique des électrons pour obtenir un plasma ion-ion, et (iii) l'étage d'accélération des ions utilisant des grilles polarisées alternativement pour créer un champ électrique dont le sens varie dans le temps. Durant ma thèse, j'ai travaillé essentiellement sur les premier et troisième étages sur deux prototypes de PEGASES. Un plasma ion-ion a été obtenu dans le premier prototype à partir de SF6 grâce à un filtrage magnétique important. Mais des limitations inhérentes et significatives rendent les performances insuffisantes pour le processus d'accélération voulu. Afin d'obtenir une source d'ions électriquement performante, le second prototype utilise une source inductive plane avec une bobine à noyau de ferrite et une boîte d'accord d'impédance comportant un transformateur à faibles pertes. Le couplage capacitif parasite a été réduit en optimisant la boîte d'accord et les progrès sont évalués grâce à la mesure du spectre du potentiel plasma par sonde capacitive. Le plasma est étudié à l'aide de sondes de Langmuir et d'un analyseur de l'énergie des ions (RFEA) dans les deux prototypes. Le potentiel d'un plasma ion-ion peut être contrôlé par une électrode polarisée en contact avec le plasma. L'accélération des ions issus du plasma ion-ion est étudiée dans le cas continu où la polarisation des grilles est fixée puis en imposant une tension créneau d'amplitude comprise entre 0 et ± 350 V avec une fréquence de 1 kHz. Dans le cas alternatif, les ions positifs et les ions négatifs sont accélérés durant les demi-périodes de polarisation positive et négative respectivement. L'énergie respective des deux populations d'ions peut être contrôlée indépendamment, en continu et en alternatif. Avec ces résultats est démontrée la faisabilité du concept PEGASES et l'étude du propulseur peut passer à l'étape de développement et réalisation.
4
Marx, Jean-Marcel. "Etudes sur la génération non inductive de courant dans un plasma." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37609211r.
Повний текст джерела
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Canturk, Mehmet. "Modeling Of Helically Applied Current To The Inductively Coupled Radio Frequency Plasma Torch In Two Dimensions." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12604691/index.pdf.
Повний текст джерелаАнотація:
The electrodeless plasma discharge is typically driven by radio frequency (RF)
power supply within the range (0.2 ¡40 MHz). The applied power is coupled into the plasma inductively called inductively coupled plasma (ICP). RF ICP technique has achieved significance importance in a diversity of research and industrial applications for over the last threes decades. It is still required to undertake both theoretical and experimental research. In this work, RF ICP technique is applied on the torch modeling in 2D. Based on extended electromagnetic vector potential representation, an axisymmetric model in 2D is proposed for the calculations of the electromagnetic fields in an RF ICP torch. The influence of axial vector potential is included to the vector potential formulations. This is achieved by imposing a helical current carrying wire configuration. The corresponding governing equations are solved numerically by applying finite element method (FEM) using commercial partial differential equation solver (Flex PDE3). Based on this model, the plasma behavior and properties are examined in terms of plasma parameters. Besides, a comparative iii analysis is made between proposed model called helical configuration and the one currently available in the literature called circular configuration. This study shows relatively little difference between temperature fields predicted by two models. However, significant difference is observed between corresponding flows and electromagnetic fields. Especially, tangential flow which is observed in helical configuration vanishes in circular configuration. The proposed model offers an effective means of accounting for the variations of the helical coil geometry on the flow and temperature fields and achieving a better representation of the electromagnetic fields in the discharge. Finally, it is concluded that minimum number of turns (n = 2) yields significant difference between two models whereas, maximum allowable number of turns yield no distinctions on the results of two models in terms of azimuthally applied current. However, axial effect of current still exists but very small with respect to the result obtained with minimum number of turns.
6
Ndzogha, Cyrille. "Etudes des phénomènes d’échange dans la purification du silicium par plasma et induction." Grenoble INPG, 2005. https://theses.hal.science/tel-01340596.
Повний текст джерелаАнотація:
Ce travail de thèse porte sur un procédé plasma de purification de silicium pour usages photovoltaïque. Il est appliqué à deux types de matériaux : du silicium d’origine métallurgique et des produits de recyclage des boues de sciage des lingots et des plaquettes de la filière photovoltaïque. Les boues de sciage des plaquettes sont essentiellement constituées de liquide de coupe, de particules de SiC (abrasif), de microparticules de silicium et de microparticules de fer provenant du fil de découpe. Le silicium de ces boues est un silicium de haute pureté, qui est déjà de qualité photovoltaïque. Il peut représenter jusqu’`a 60 % du poids initial du lingot. Le procédé objet du projet comporte une phase de séparation du SiC par centrifugation, suivi d’une phase d’élimination chimique du fer, puis d’un traitement par plasma réactif pour l’élimination du SiC résiduel. Ce travail porte sur cette dernière phase. Un traitement plus complexe que celui initialement prévu a été rendu nécessaire par l’existence dans les boues de sciage de particules de SiC provenant du bris des grains de l’abrasif initial. La séparation du SiC étant incomplète, le traitement par plasma a dû éliminer des quantités beaucoup plus importantes qu’initialement prévu. Cela a nécessité une modification importante du procédé initial, et la mise au point de phase de pré-traitement destiné à rendre exploitable par le plasma le produit issu de la séparation. Ce travail combine études théoriques, modélisations numériques et expérimentation. La modélisation thermodynamique permet de déterminer les meilleures conditions d’élimination des polluants (gaz réactifs adaptés, débits, températures, pressions) tandis que la modélisation du brassage électromagnétique mesure l’efficacité du renouvellement de la surface du bain liquide au cours du traitementThis thesis focuses on a plasma process of purification of silicon for photovoltaic applications. It is applied to two types of materials: metallurgical silicon and recycling products from sawing sludge ingots and from wafers of photovoltaic industry. Platelet sawing sludge consist mainly of cutting fluid, SiC particles (abrasive), silicon microparticles and iron micro-particles from the cutting wire. Silicon sludge is a high-purity silicon, which is already of photovoltaic quality. It can represent 60% of the original weight of the ingot. The present process comprises a SiC phase separation by centrifugation, followed by chemical elimination phase of the iron, then a reactive plasma treatment for removing residual SiC. This work deals with this last phase. A more complex treatment than originally planned was made necessary by the existence in the SiC particles of sawing sludge from the initial breaking of the abrasive grains. Separation of SiC is incomplete, the plasma treatment had to remove much larger quantities than originally planned. This required a significant modification of the original process, and the setting of a pre-treatment phase point intended to make it usable by the product of the plasma separation. This work combines theoretical studies, numerical modeling and experimentation. Thermodynamic modeling to determine the best conditions for the removal of pollutants (adapted reactive gases, flow rates, temperatures, pressures) whereas modeling the electromagnetic measurement brewing efficiency renewing the surface of the liquid bath during treatment
7
Guglielmi, Alexandre. "Propulseur à courant de Hall double étage à source RF inductive : étude expérimentale du fonctionnement et des instabilités basses fréquences." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30243.
Повний текст джерелаАнотація:
Contrairement aux propulseurs chimiques servant à la mise à poste, les propulseurs électriques à courant de Hall sont des moteurs de petite taille utilisés pour le maintien à poste des satellites, le changement d'orbite et les missions interplanétaires. Souvent caractérisés par de faibles poussées, ils ont l'avantage d'avoir une vitesse d'éjection et une impulsion spécifique très importantes. Le principe de fonctionnement est basé sur l'ionisation d'un gaz rare (Xe, Kr) par une différence de potentiel appliquée au travers d'une barrière magnétique. La conductivité électronique localement plus faible dans la barrière conduit à créer un champ électrique dans cette région. Les ions sont alors soumis à ce champ et sont donc accélérés à des vitesses pouvant dépasser plusieurs dizaines de km/s. Le champ électrique au niveau de cette barrière est alors responsable de l'accélération des ions et donc, simultanément, de la poussée et de l'impulsion spécifique. Afin de pouvoir agir indépendamment sur ces deux derniers paramètres, un propulseur à courant de Hall double étage (ID-Hall, Inductive Double stage HALL thruster)) a été développé. Le premier étage est l'étage d'ionisation, constitué d'une source plasma indépendante à couplage inductif, et le second étage est l'étage d'accélération constitué de la barrière. À partir de différents outils de mesures (sonde de flux ionique, analyseur à champ retardateur, caméra haute vitesse, sondes courant-tension, anode segmentée, ...) et d'un modèle numérique (HALLIS), nous avons pu caractériser le plasma, ses instabilités, et les performances du propulseur. Malgré la cartographie magnétique singulière de ce propulseur, les caractéristiques en fonctionnement simple étage sont comparables à celles des propulseurs à courant de Hall classiques. En fonctionnement double étage, la source RF affecte de manière significative le transport des électrons dans le propulseur. De plus, d'autres résultats en double étage montrent qu'à basses tensions de décharge, le courant de décharge est inférieur à celui en simple étage. L'énergie des ions extraits est plus élevée en double étage et le courant d'ion présente une diminution avec l'augmentation de la puissance RF mais reste proche de celui en simple étage. Cette étude a été réalisée en Xénon et en Argon. Des oscillations basses fréquences de grandes amplitudes (Breathing Mode) ont été observées expérimentalement, analysées par sonde résolue en temps et comparées à des résultats obtenus par le modèle. D'autres instabilités azimutales (Rotating Spokes) ont aussi été mises en évidence, ainsi qu'étudiées électriquement et par imagerie.[...]Unlike chemical thrusters, electric Hall current thrusters are small motors used for station keeping, orbiting, and interplanetary missions. Often characterized by low thrusts, they have the advantage of having a very high ejection speed and specific impulse. The principle is based on the ionization of a rare gas (Xe, Kr) by a potential difference applied through a magnetic barrier. The locally weaker electronic conductivity in the barrier leads to the creation of an electric field in this region. The ions are then subjected to this field and are therefore accelerated to speeds which may exceed several tens of km/s. The electric field at this barrier is then responsible for the acceleration of the ions and therefore, simultaneously, for the thrust and the specific impulse. In order to modify independently these two parameters, a double stage Hall thruster (ID-Hall, Inductive Double stage HALL thruster)) has been developed. The first stage is the ionization stage, consisting of an independent plasma source (ICP source), and the second stage is the acceleration region with the magnetic barrier. Using different diagnostics (ionic flux probe, retarding potential analyzer, high speed camera, current-voltage probes, segmented anode, etc.) and a numerical model (HALLIS), we were able to characterize the plasma, its instabilities, and thruster performance. Despite the singular magnetic mapping of this thruster, the characteristics in single stage operation are comparable to those of conventional Hall current thrusters. In dual-stage operation, the RF source significantly affects the transport of electrons in the thruster. In addition, other double-stage results show that at low discharge voltages, the discharge current is lower than at single stage. The energy of the extracted ions is higher in double stage and the ion current decreases with increasing RF power but remains close to the ion current in single stage. This study was carried out in Xenon and Argon. Low-frequency oscillations of large amplitudes (Breathing Mode) were observed experimentally, analyzed by time-resolved probe and compared to results obtained by the model. Other azimuthal instabilities (Rotating Spokes) have also been identified as well as studied electrically and by imaging. As soon as the source is active, at low RF power, these previous instabilities are strongly attenuated, while at higher power, other azimuthal instabilities appear (Striations). These azimutals instabilities were also studied around the source alone, by imaging in different gases and using a PIC-MCC model
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Besseler, Edmilson. "Construção e caracterização de um reator indutivo : ICP para corrosão de materiais." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259745.
Повний текст джерелаАнотація:
Orientadores: Peter Jurgen Tatsch, Stanislav A. MoshkalyovDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-11T19:17:46Z (GMT). No. of bitstreams: 1 Besseler_Edmilson_M.pdf: 3143419 bytes, checksum: 2715af82a31f1728537a14b1764455a6 (MD5) Previous issue date: 2008
Resumo: Esta dissertação apresenta as etapas do trabalho de construção de um Reator ICP destinado a processos de micro fabricação, mais precisamente, destinado a corrosões profundas de Silício a taxas de corrosões elevadas. O modelamento e as caracterizações do reator ICP foram feitas através de um protótipo e depois aplicadas a um equipamento da LAM Research que funcionava em modo RIE. Este foi adaptado para trabalhar em modo ICP, de acordo com os parâmetros obtidos no protótipo. Para isso, foi necessário a instalação do Equipamento e fornecer toda a infra-estrutura que este necessitava para seu funcionamento. Foram desenvolvidos casadores de impedância para ligação dos geradores de RF à bobina do ICP e do eletrodo de polarização da amostra, controladores de fluxo de gases, chaveadores manuais para válvulas pneumáticas, sistemas de refrigeração e tubulação de vácuo. O plasma foi caracterizado e alguns processos foram realizados com o intuído de mostrar o comportamento com relação à variação de parâmetros como pressão, potência, polarização da amostra, fluxo de gases, tempo de processo, área da lâmina exposta ao plasma e também o comportamento de diferentes tipos de máscaras. O Equipamento também foi preparado para que seja possível a comutação de gases, que futuramente será automática, de modo que se possa realizar corrosões e polimerizações consecutivas, como ocorre em processos Bosch.
Abstract: This dissertation shows the steps to building an ICP Reactor dedicated to micro fabrication process, further to deep etching of Silicon on high rates. The modeling and characterization of ICP Reactor has been done in a prototype and after applied on an RIE equipment from LAM Research, that was adapted to work in ICP mode like the prototype. To do it was necessary equipment installation and give it the infra structure needed to it works. A network matching was developed to connect the RF generator to ICP coil and to the electrode of wafer polarization, such as gas flow controllers, manual switches for pneumatic valves, cooling systems and vacuum pipes. The plasma was characterized and some processes has been realized in order to show the trends against some parameters variation as pressure, power, sample polarization (bias), gas flow, process time, wafer area exposed to the plasma and also the behavior of different kind of masks. The equipment is ready to switch some gases, which will be automatic in the future, to corrosion and polymerization consecutive process as at a Bosch process.
Mestrado
Eletrônica, Microeletrônica e Optoeletrônica
Mestre em Engenharia Elétrica
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Plihon, Nicolas. "Stabilité et structure électrique d'une décharge inductive en gaz électronégatif." Phd thesis, Ecole Polytechnique X, 2006. http://tel.archives-ouvertes.fr/tel-00083948.
Повний текст джерелаАнотація:
Les plasmas inductifs radiofréquence basse pression sont utilisés pour la gravure de motifs nanométriques. Ces plasmas contiennent des ions négatifs et peuvent être soumis à deux types d'instabilités. La première est décrite par des oscillations de relaxation entre les modes de couplage de l'énergie capacitif (E) et inductif (H). Les mesures temporelles au cours de ces oscillations sont conformes aux résultats publiés. L'autre instabilité, liée au transport des espèces chargées, n'existe que lorsque le plasma peut diffuser. Des mesures spatio-temporelles montrent que les fluctuations des paramètres plasma sont liées à la formation et à la propagation périodique d'une double couche d'amplitude moyenne. Cette double couche est une gaine interne séparant un plasma haute densité, forte température électroniques et sans ions négatifs dans la source d'un plasma faible densité, faible température électronique et de forte fraction d'ions négatifs dans la chambre de diffusion. Cette double couche propagative apparaît lorsque la fraction d'ions négatifs dépasse un seuil. Sous ce seuil, la double couche est statique et disparaît pour des fractions d'ions négatifs très faibles. Les transitions entre ces trois états sont soumises à une forte activité acoustique ionique. L'ajout d'un champ magnétique modifie le chauffage des électrons par absorption de l'onde hélicon (mode W). Des oscillations de relaxation H/W ont été observées dans une fenêtre restreinte de paramètres. D'autre part, le confinement des espèces chargées est modifié: au centre, le plasma ne contient pas d'ions négatifs; au bord, le plasma ne contient plus d'électrons, un plasma ions - ions a été créé.
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Dehbi, Leila. "Study of a radio-frequency inductive plasma discharge used to deposit an amorphous hydrogenated carbon thin film." Doctoral thesis, Universite Libre de Bruxelles, 1998. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212056.
Повний текст джерела
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Mostajeran, Goortani Behnam. "Synthèse et évaluation de la taille et de la morphologie des nanoparticules de SIO[indice inférieur 2] dans un réacteur plasma RF à couplage inductive." Thèse, Université de Sherbrooke, 2006. http://savoirs.usherbrooke.ca/handle/11143/1790.
Повний текст джерелаАнотація:
The synthesis of SiO[indice inférieur 2] nanoparticles in radio frequency (RF) plasma reactors is studied.The effect of feed rate, quench gas injection and reactor configuration, on the final size distribution and morphology of the prepared nanoparticles, are investigated.The laser scattering is used as a technique complementary to scanning electron microscopy (SEM) and the nitrogen absorption (BET) techniques, to determine the morphology, size and aggregation level of the resulting nanopowders. It is demonstrated that the quench gas configuration and reactor geometry can now be designed to control the morphology and size of the nanoparticles in these reactors. Depending on the preparation conditions and the reactor configuration chosen, various nanostructured products have been synthesised: i.e. highly aggregated nanostructured, partially sintered nanospheres and spherical nanoparticles with very low levels of aggregation. These nanostructures have their primary particles sized between 10 and 200 nm, while the aggregates sizes can lie in the range of between hundreds of nanometer to several micrometers. Computational fluid dynamics (CFD) modelling, using Fluent 6.2.16, and the fine particle model (FPM) are further employed to better understand the time-temperature history of the generated particles.The results are utilised to describe the effects of the above mentioned parameters on the formation (nucleation and growth) of the nanoparticles and clusters by various mechanisms. By combining the experimental measurements with the numerical results, the critical parameters that should be considered for a large scale production process are identified as: establishing the proper quench gas configuration, the extension of high temperature regions and the reduction of fluid circulations within the reactor.
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Dubois, Loic. "Etudes expérimentales du concept de propulseur de Hall double étage." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30320/document.
Повний текст джерелаАнотація:
Dans un propulseur à courant de Hall, la création des ions et leur accélération sont régis par le même phénomène physique. L'idée du propulseur de Hall double étage (DSHT) est de découpler l'ionisation du gaz (poussée) et l'accélération des ions (ISP), de sorte à rendre le système davantage versatile. Les travaux menés durant cette thèse visent à démontrer, grâce à des essais expérimentaux, la pertinence et la faisabilité d'un tel concept. Dans un premier temps, un prototype de DSHT, baptisé ID-HALL, a été conçu et assemblé. Il est constitué d'une source inductive magnétisée insérée dans un tube en céramique et d'un étage d'accélération identique à une barrière magnétique de propulseur simple étage. La source inductive a été optimisée de sorte à réduire le couplage capacitif et à maximiser l'efficacité du transfert de puissance par ajout de pièces en ferrite et diminution de la fréquence RF d'excitation. Dans un deuxième temps, la source inductive du propulseur a été caractérisée indépendamment du propulseur en argon et xénon pour différentes pressions. Le dispositif expérimental a permis notamment de tracer une cartographie 2D de la densité et de la température. Enfin, le propulseur a été monté dans son caisson et des mesures préliminaires (caractéristiques courant-tension, mesures par sonde RPA) ont été menées. En parallèle, des simulations utilisant un modèle hybride 2D ont été effectuées en mode simple et double étage. Elles mettent en évidence un fonctionnement versatile du moteur pour des tensions inférieures à 150 V. A terme, on visera à démontrer que la densité de courant et l'énergie des ions peuvent être, dans certaines conditions, significativement découpléesIn Hall thrusters, the same physical phenomenon is used both to generate the plasma and to accelerate ions. Furthermore, only a single operating point is experimentally observed. The double stage Hall thruster (DSHT) design could allow a separate control of ionization (thrust) and ions acceleration (ISP) to make the system more versatile. The work carried out during this PhD aims to experimentally demonstrate the relevance and the feasibility of this concept. Firstly, a new design of DSHT, called ID-HALL, was proposed and a new prototype was built. It combines the concentric cylinder configuration of a single stage Hall thruster with a magnetized inductively coupled RF plasma source (ICP) whose coil is placed inside the inner cylinder. The ICP source was improved in terms of power coupling efficiency by adding ferrite parts and by decreasing the heating RF frequency. The ICP source used in the ID-HALL thruster was then characterized independently of the thruster using argon and xenon and varying pressure. The experimental setup has allowed to measure the spatial variations of the electron density and temperature. Finally, the thruster was mounted in its vacuum chamber and preliminary measures (voltage-current characteristics, RPA measurements) were led. At the same time, simulations using a two-dimensional hybrid model were performed in single and double stage. A versatile operation for voltages lower than 150 V was highlighted. An emphasis will be given to demonstrate that the current density (given by the ion flux probe) and the ions energy (given by the RPA) might be significantly decoupled
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Nessim, Christine. "Synthèse des poudres ultrafines de TiO2 par plasma inductif Induction plasma synthesis of ultrafine titanium dioxide powders /." [S.l. : s.n.], 2001.
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Fukumoto, Hiroshi. "Model Analysis of Plasma-Surface Interactions during Silicon Oxide Etching in Fluorocarbon Plasmas." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/158076.
Повний текст джерела
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Zuber, Matthew E. "Investigation of magnetofluiddynamic acceleration of subsonic inductively coupled plasma." Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210898.
Повний текст джерелаАнотація:
Electromagnetic acceleration has the potential for various applications stemming from space electric propulsion systems to future air breathing hypersonic augmentation.Electromagnetic acceleration uses electromagnetic body force produced by the interactions of currents carried in plasma which is either externally applied or self-induced magnetic fields to accelerate the whole body of gas. Historically, these plasmas sources have been arc jets, shock tube and microwaves. Never has an electromagnetic accelerator been powered by an inductively coupled plasma (ICP) source.
The von Karman Institute has experimentally investigated the acceleration of an electrically conductive fluid produce by a subsonic ICP source. This ICP source was powered with a 15 kW and 27.1 MHz radio frequency facility called the Minitorch. The electromagnetic acceleration was accomplished with the design, fabrication and testing of a linear Hall current magnetofluiddynamic accelerator (MFDA) channel. The channel was geometrically orientated into the Hall configuration to accounts for the large Hall Effect. This channel used a single pair of copper annulus electrodes powered by a 10 kW direct current power supply. The channel was water cooled and contained various diagnostics to provide greater insight to the electromagnetic acceleration process. This was the first successful magnetofluiddynamic acceleration of an ICP source and validates the proof of concept.
One-dimensional MFD modeling was formulated and used to determine the necessary performance requirements of the MFDA channel E and B field subsystems. An interaction parameter of approximately 2.25 was required for the doubling of an inlet velocity of 300 m/sec. The required subsystem need to provide a current density was 6 Amps/cm2 with a magnetic field strength of 0.50 Tesla over an acceleration length of 0.1 meters. Additional the most critical constraint was the thermal management subsystem which was designed to overcome large heat transfer fluxes to achieve a steady state condition over a test run of 10 minutes.
The dynamic pressure measured increase the inlet velocity 101% for an argon plasma flowing at 1.01 g/s at a magnetic field strength of 0.49 Tesla. his strong acceleration of the plasma was most notable near the region of the electrodes at the exit of the 0.1 m long channel. The central region of the plasma has less dynamic pressure increase corresponding to only a maximum of 15% increase in velocity at a magnetic strength of 0.49 Tesla. Experimental results showed that axial discharge voltages increased with increased magnetic fields, indicating a strong Hall Effect in the accelerator as expected.
Theoretical analysis was accomplished using the one-dimensional equation of motion and was compared to utilizing only the momentum equation. Experimental force fluxes were compared to the calculated values of the one-dimensional equation of motion and momentum equation. The reference area for the current density was selected from intensity measurement using a high speed camera with the MFDA channel on. There was significant error in the analysis concerning using the momentum Lorentz force only versus the one-dimensional equations of motion; which included joule heating. This analysis summarized the necessity to include joule heating in the formulation of the problem.
Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished
16
Okpalugo, Osmond A. "Characteristics of argon-chlorine inductively coupled plasmas for plasma surface modification and etching." Thesis, University of Ulster, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399684.
Повний текст джерела
17
Schreuders, Cornelis. "Synthèse par plasma inductif de particules nanométriques de silicium : optimisation de la trempe." Limoges, 2006. http://aurore.unilim.fr/theses/nxfile/default/eaa5dec8-f4a4-4245-9423-2e6d8d1337a5/blobholder:0/2006LIMO0029.pdf.
Повний текст джерелаАнотація:
Une étape importante de la synthèse de nanoparticules par plasma inductif est la trempe de la phase gazeuse. Cette trempe modifie les profiles de température et de vitesse des gaz, et donc la distribution de taille des particules produites ainsi que leur composition cristallographique. Cette étude théorique et expérimentale démontre ces effets sur les propriétés des particules en fonction de paramètres de trempe, tels que la géométrie de l’anneau de trempe, le nombre d’injecteurs et le flux de gaz. Les profiles de température et de vitesse du plasma ont été modélisés par CFD puis validés expérimentalement en fonction de paramètres de procédé, tels que la puissance de couplage, la pression du réacteur, les flux de gaz du plasma. La croissance des particules a aussi été modélisée, puis comparée à des résultats expérimentaux sur la synthèse de nanopoudres de silicium. L’influence de la trempe sur la formation de différentes phases cristallines a été démontrée sur le carbure de tungstèneAn important step in the synthesis of nanoparticles by means of an inductively coupled plasma (ICP) process is quenching, which is the fast controlled cooling of the plasma gas. As quenching is influencing the temperature and velocity profiles, it is also affecting the particle size, size distribution, and phase composition of the product. In this work, the effect of several quench parameters, like nozzle number, nozzle diameter, quench gas flow rate, etc. , on the final particle size has been investigated both theoretically and experimentally. The influence of the quench and other process parameters (plate power, pressure, gas flow rates, …) on the plasma’s temperature and velocity profiles has been modelled using CFD and validated with experimental results. The particle size was modelled using a particle growth model and has been compared to results obtained from experiments with silicon. The effect of quenching on the product chemistry has been demonstrated for tungsten carbide
18
Pan, Changkang. "Characterization of solvent-plasma interactions for inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/30536.
Повний текст джерела
19
Ye, Rubin. "La dispersion turbulente et l'évaporation des particules dans des plasmas à couplage inductif Turbulent dispersion and particle evaporation in inductively coupled plasmas." Sherbrooke : Université de Sherbrooke, 2002.
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20
Despiau-Pujo, Emilie. "Gravure des semi-conducteurs III-V par plasmas inductifs chlorés." Phd thesis, Ecole Polytechnique X, 2009. http://pastel.archives-ouvertes.fr/pastel-00005582.
Повний текст джерелаАнотація:
Ce travail de thèse s'inscrit dans un domaine de recherche émergeant : la gravure par plasma pour la photonique et l'opto-électronique. La maîtrise des procédés de gravure passe par la prédiction des énergies et des flux d'espèces produites dans le plasma en fonction des paramètres de la décharge, ainsi que par la compréhension des mécanismes d'interaction plasma-surface. Ce travail aborde ces deux aspects au travers de modélisations fluides et de simulations atomistiques. Nous avons développé des simulations de dynamique moléculaire pour comprendre les mécanismes fondamentaux qui régissent la pulvérisation de deux semiconducteurs III-V (GaAs et GaN) par des ions Ar faiblement énergétiques. Cette étude numérique, confrontée à une série d'expériences, montre que la composition des matériaux bombardés est modifiée sur quelques dizaines d'angströms et que les atomes de Ga pulvérisés quittent la surface avec des énergies suffisantes pour endommager les flancs de gravure et briser les couches de passivation, notamment dans les procédés dominés par bombardement ionique. Nous avons également travaillé sur des simulations fluides (bi-dimensionnelles et globales) pour comprendre la dynamique des décharges inductives chlorées et étudier le transport des espèces au sein du plasma. Des confrontations modèle/expérience montrent que le modèle fluide 2D surestime les densités des particules chargées mais prédit de façon satisfaisante la composition neutre et ionique du plasma. Le modèle global constitue le premier pas vers une modélisation du régime basse puissance des plasmas inductifs chlorés ; il nous a permis d'étudier les instabilités qui se développent à la transition E-H.
21
Nakazaki, Nobuya. "A Study of Plasma-Induced Surface Roughness and Ripple Formation during Silicon Etching in Inductively Coupled Chlorine Plasmas." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215513.
Повний текст джерела
22
Nwogu, Vincent Ikechukwu. "Electrothermal vaporization sample introduction for inductively coupled plasma atomic emission and inductively coupled plasma mass spectrometry." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/30762.
Повний текст джерела
23
Chen, Hsin-Yi. "Inductively coupled plasma etching of InP." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0021/MQ54126.pdf.
Повний текст джерела
24
Bora, Selin. "Boron Determination In Body Fluids By Inductively Coupled Plasma Optical Emission Spectrometry And Inductively Coupled Plasma Mass Spectrometry." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611499/index.pdf.
Повний текст джерелаАнотація:
Boron element plays an important role for our country since approximately 70% of the world&rsquos reserves are in Turkey. It is widely used in different areas of industry. Besides being vital for the plants, it is important also for human health. It has been shown that high boron exposure does not affect fertility negatively and also with an increasing boron exposure, risk of prostate and cervical cancers decreases. There are different opinions regarding health effects of boron. There are both positive and negative findings. Therefore, determination of boron in body fluids such as urine and blood is necessary to monitor exposed concentration level and its relation with diseases. Furthermore, these studies may contribute to define a reference value for safe maximum daily boron intake. In this study, a method previously developed by our research group was applied for the determination of boron in urine samples. Urine and blood samples were collected from human subjects living or working in different regions of Balikesir where boron reserves are located. While urine analysis was done by using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), due to lower concentrations of boron in blood, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used for blood analysis. A sensitive method was developed using ICP-MS. Samples were digested in microwave oven by applying optimized digestion procedures. Indium (In) and Beryllium (Be) internal standards were spiked into the urine and blood samples, respectively. A sample introduction system containing no glass or silica surfaces was used in ICP-MS to eliminate boron memory effect. Two isotopes of the boron, 10B and 11B, were monitored during the study. Space charge effect due to Na+ ion and carbon interference on B and Be signals was investigated in detail. Limit of Detection was 0.021 mg/L for ICP-OES and it was 2.2 µ
g/L for ICP-MS. The accuracies of the methods were checked by using NIST 1573a Tomato Leaves and BCR Human Hair certified reference materials for urine and blood, respectively.
25
Meziani, Tarik. "Développement d'une source plasma haute-densité à couplage inductif améliorée par adjonction d'un noyau magnétique : application au dépôt de couches minces de carbone adamantin." Orléans, 2002. http://www.theses.fr/2002ORLE2056.
Повний текст джерелаАнотація:
Ce travail porte sur le développement d'une nouvelle source inductive permettant le dimensionnement vers un réacteur de grande surface. Nous avons pu montrer que l'adjonction d'un noyau magnétique permet d'accroître l'intensité de la composante radiale de l'induction magnétique entraînant une augmentation de la puissance absorbée et de la densité plasma. L'utilisation combinée d'un noyau magnétique et d'un diélectrique d'épaisseur réduite permet de multiplier la densité de particules chargées par un facteur 3. Comparée à une source classique utilisant une antenne prenant la forme d'une spirale, ce dispositif présente des performances bien meilleures avec notamment une densité ionique supérieure d'un facteur 2, et une meilleure uniformité du plasma qui reste de l'ordre de 5% sur la surface délimitée par le diamètre de l'antenne. Les résultats obtenus avec ce dispositif ont permis un dimensionnement à plus grande échelle vers une source de 80 x 80 cm2. Les principales limites à une bonne uniformité, liées aux phénomènes d'ondes stationnaires ainsi qu'au profil du champ électromagnétique induit, ont été résolus. L'uniformité du plasma est de l'ordre de 10% sur 60 x 60 cm2 avec une densité supérieure à 1011 cm-3. Enfin, l'application de la nouvelle source de 200 mm au dépôt de couches minces de carbone amorphe hydrogéné a permis la croissance rapide (> 150 nm/min) de couches relativement dures (dureté > 25 GPa). Les propriétés mécaniques des couches déposées ainsi que la vitesse de croissance ont été reliées au diagnostic de la phase gazeuse effectué principalement par spectrométrie de masse et par spectroscopie optique d'émission.
26
Gouy, Pierre-Alban. "Etudes spectrométriques de plasmas de rentrées atmosphériques (Mars-Terre) par torche plasma à couplage inductif à basse pression." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22608/document.
Повний текст джерелаАнотація:
La mise en œuvre de missions spatiales demande à développer de nombreuses technologies clés afin de surmonter certaines étapes cruciales. L’une d’entre elle concerne la rentrée atmosphérique : lorsque le véhicule pénètre dans la couche d’atmosphère, sa vitesse relative très grande par rapport au sol va engendrer des frottements importants ainsi qu’une augmentation de pression. L’énergie cinétique de l’objet va donc être transformée en énergie thermique et chauffer le gaz en formant une onde de choc. Les températures dépendent de la vitesse initiale, de la composition de l’atmosphère et de sa pression. Le gaz ainsi chauffé va s’ioniser et devenir un plasma, il va donc transférer sa chaleur au corps de la sonde non seulement par convection mais aussi par rayonnement. Afin de se protéger, le véhicule dispose d’un bouclier thermique pouvant résister aux phénomènes extrêmes rencontrés lors de la descente. Les contraintes supplémentaires vont imposer une géométrie particulière et un lourd bouclier. Ainsi l’objectif est d’avoir les protections les plus légères et efficaces possibles afin de permettre à la sonde de maximiser son emport en équipement scientifique. Pour cela, un des paramètres clés est de connaître le comportement et le rayonnement du plasma produit lors de la rentrée dans l’atmosphère. Cette thèse se positionne dans ce domaine d’étude: les expériences montées et réalisées ont pour objectif d’observer par moyens spectroscopiques un plasma correspondant à celui rencontré par les sondes spatialesMany key technologies, to overcome some crucial steps, are needed for space missions. One of them concerns the re-entry: when the vehicle enters the atmosphere layer, its high velocity relative to the ground will generate significant friction and an increase in pressure. The kinetic energy of the object will be converted into heat energy and heat the gas forming a shock wave. Temperatures depend on the initial velocity, the atmosphere composition and its pressure. The gas is ionized and become plasma, it will therefore transfer its heat to the body of the probe not only by convection but also by radiation. To protect itself, the vehicle has a heat shield that can withstand extreme phenomena encountered during the descent. Additional constraints will impose a particular geometry and a heavy shield. So the goal is to have the lightest possible and effective protections to allow the probe to maximize its payload. For this, one of the key parameters is to know the behavior of the plasma and radiation produced during re-entry into the atmosphere. This thesis is positioned in this area of study: experiments to create a re-entry plasma are intended to be observed by a spectrometer
27
Oberste, Berghaus Jürg. "Induction plasma deposition of diamond thin films." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20153.
Повний текст джерелаАнотація:
Diamonds unrivaled properties generate an enormous potential in industrial applications for thin film diamond coatings. Diamond has the highest values of hardness, thermal conductivity and elastic modules of any known material. Polycrystalline diamond coatings can be produced from thermal plasmas by Chemical Vapor Deposition (CVD). The films created by this process are often very non uniform over the deposition area. The properties of the free flowing plasma above the deposition surface and the plasma chemistry in the boundary layer above the growing film are believed to play fundamental roles in the formation of the diamond film and its uniformity.In this study, an Ar/H2/CH4 plasma (8.65% H 2, 0.25% CH4) was created by a rf inductively coupled plasma torch for the deposition of diamond thin films on a molybdenum substrate probe (5 mm diam.). With the probe surface oriented normal to the plasma flow, growth rates in the order of 70 gm/hr were obtained for highly crystalline continuous films. Temperature and electron density profiles in the plasma free flow were determined from measurements by emission spectroscopy. (Abstract shortened by UMI.)
28
Webb, Douglas P. "Intelligent autonomous inductively coupled plasma instrumental operation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0010/NQ30413.pdf.
Повний текст джерела
29
Oberste, Berghaus Jörg. "Induction plasma deposition of diamond thin films." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ44100.pdf.
Повний текст джерела
30
Young, Anita. "Fluorescence studies in the inductively coupled plasma." Thesis, University of Plymouth, 2002. http://hdl.handle.net/10026.1/1686.
Повний текст джерелаАнотація:
An Optima 3000 ICP-AES instrument was modified and the equipment necessary to carry out axial excitation atomic fluorescence was designed and constructed. Using this calibrated system, preliminary fluorescence experiments were not successful. As fluorescence is proportional to source intensity, it was considered that the excitation source, a hollow cathode lamp, may not have been sufficiently intense to produce fluorescence. A novel excitation source-driver system was designed and built in-house to operate HCLs, BDHCLs and LEDs with variable modulation frequencies and duty cycle capabilities. Studies investigating lamp response to changes in modulation frequency and duty cycle indicated that a lamp operated with a lower modulation frequency range (167 - 542 Hz) and higher duty cycles (30 - 50 %) should provide the preferred intense excitation conditions for the production of fluorescence in the ICP, When a Thermo Elemental PQ2 instrument was used, fluorescence was obtained immediately. Um'variate searches were used to optimise several plasma parameters, i.e. forward power; viewing height ALC; plasma, nebuliser and auxiliary gas flow rates. Once the optimum conditions had been determined, calibration curves were plotted for each of the elements studied (Ba, Li, Mg and Na). The calibration showed excellent linearity over five orders of magnitude (R? values ranged from 0.99995 to 1.0000) and the precision on each data point was better than 5 % RSD. Limits of detection were determined to be 27.6, 0.51, 0.43 and 0.20 ug 1* for Ba, L i , Mg and Na, respectively, which approached those reported in the literature for a commercial system. Vertical profiles of the plasma, using radial excitation, were obtained for Ba, Li , Mg and Na. Using the optimum conditions for Li and Na, vertical profiles of the plasma, using axial excitation with the more intense LEDs, were obtained. Both profiles showed that there was a relatively sharp optimum, with respect to fluorescence signal, as a function of viewing height ALC. The optimum viewing heights ALC obtained, for both radial and axial excitation fluorescence, were identical, suggesting that, irrespective of the excitation arrangement employed, only particular conditions produced in the plasma give the optimum conditions for fluorescence and that these are spatially dependent. Plasma diagnostics were performed in an attempt to explain why fluorescence was observed using the plasma produced by the Thermo Elemental but not by the Optima 3000 generator. At a viewing height of 50 mm ALC, Texc and Trot were 3080 and 2500 K for plasmas produced using the Thermo Elemental generator and 3600 and 2830 K for the Optima 3000 generator, respectively. Temperatures were calculated using the mean emission intensity at particular wavelengths. The intensities of the emitting species from the Thermo Elemental ICP were lower than those obtained from the Optima 3000 ICP for supposedly 'identical' conditions. If the number of excited species gives rise to lower emission intensities, then there must be more atoms in the lower/ground state from the plasma produced using the Thermo Elemental generator. This is of vital importance because for fluorescence to occur the fluorescence emission intensity will be dependent on the number available in the ground state for excitation {i.e. a relatively 'cool' plasma is required for fluorescence to occur). As very similar plasma operating conditions and the same concentration solutions were used in the fluorescence experiments performed using both the Optima 3000 and the Thermo Elemental ICPs, the differences observed in plasma performance may be attributed to efficiency of coupling of the generators used.
31
Dignard, Nicolas M. "Optimisation expérimentale de la sphéroïdisation des poudres métalliques et céramiques par plasma inductif = Experimental optimization of the spheroidization of metallic and ceramic powders with induction plasma." Sherbrooke : Université de Sherbrooke, 1998.
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32
Dubuisson, Cendrine. "Etude des performances analytiques d'un plasma à couplage inductif ICP observé axialement en spectrométrie d'émission." Lyon 1, 1998. http://www.theses.fr/1998LYO10263.
Повний текст джерелаАнотація:
Il existe un besoin constant d'ameliorer les limites de detection des methodes d'analyse elementaire. L'observation axiale du plasma a ete proposee afin d'ameliorer les limites de detection de la spectrometrie d'emission icp, cependant son apport reel sur les performances analytiques de la methode n'a pas encore ete clairement etabli. Nous nous sommes principalement interesses aux limites de detection et aux effets de matrice. L'evaluation d'un nouveau prototype a visee axiale a egalement ete realisee. Nous avons montre que le facteur d'amelioration moyen des limites de detection en visee axiale est de 3 a 4. Ce facteur provient a la fois d'une amelioration du rapport signal sur fond et de l'ecart-type relatif du fond pour des conditions de mesure identiques. Le prototype a visee axiale que nous avons evalue presente des limites de detection plus basses que celles determinees sur les systemes commerciaux actuels. L'utilisation d'un nebuliseur ultrasonique a permis d'atteindre des valeurs comparables a celles de l'icp-ms pour certains elements. Par ailleurs, nous avons montre que les effets de matrice peuvent etre minimises en visee axiale comme en visee laterale dans certaines conditions operatoires qui conduisent a un transfert d'energie optimal entre l'echantillon et le plasma. Dans ces conditions operatoires appelees conditions robustes, la contribution des perturbations liees aux phenomenes d'atomisation et d'excitation des elements en presence d'interferent est eliminee, l'effet residuel pouvant etre attribue a une perturbation du systeme d'introduction. Il a ete montre que l'importance de ces effets varie selon le nebuliseur et la chambre de nebulisation utilises. La caracterisation des aerosols produits montre une modification des aerosols tertiaires et/ou primaires en presence d'interferent. Ces modifications dependent a la fois du systeme d'introduction et des proprietes physiques du liquide nebulise. Par ailleurs, nous avons mis en evidence le role important de la chambre de nebulisation, de nombreuses perturbations se produisant lors des processus de filtrage et de transport de l'aerosol. L'effet residuel observe en presence d'interferent dans les conditions robustes a ete corrige par la methode de l'etalonnage interne. Ainsi, l'utilisation d'un seul etalon interne permet de compenser de facon efficace une difference importante entre la matrice des echantillons et des etalons pour toutes les raies dans les deux modes d'observation.
33
Hamman, David. "A holistic view on the impact of gold and uranium mining on the Wonderfonteinspruit / David Hamman." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8155.
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34
WEBB, BRYAN DOUGLAS. "FUNDAMENTAL INVESTIGATIONS OF A 148 MEGAHERTZ INDUCTIVELY COUPLED PLASMA DISCHARGE." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188138.
Повний текст джерелаАнотація:
Fundamental investigations have been carried out on an Inductively Coupled Plasma (ICP) operated at 148 MHz, a frequency which is nearly three times higher than any previously reported for analytical ICPs used in spectrochemical analysis. High frequency operation is expected to provide easier sample introduction into the discharge, with a consequence of less energetic conditions in the central channel. Several plasma diagnostic techniques were employed in order to determine the conditions experienced by the analyte species in this source for spectrochemical analysis. Three different torch systems were investigated at 148 MHz and compared to the "standard" 27 MHz configuration. The highest excitation temperatures and electron densities were obtained in the 27 MHz configuration, and the lowest values in the largest torch at 148 MHz. Intermediate values were obtained in the intermediate-size torches at 148 MHz. These observations correlate reasonably well with the ratio of the plasma radius to the skin depth (r/s). The skin depth defines the region in which the majority of the electrical energy is deposited into the discharge, and is smaller at 148 MHz than at 27 MHz. The measurement of electron densities also allows the estimation of how closely a particular discharge approaches Local Thermal Equilibrium (LTE). As may be expected, LTE is most closely approached in the 27 MHz arrangement. The less energetic conditions characterized by lower temperatures and electron densities result in less intense analyte emission from the high frequency ICPs. Signal-to-Background ratios and detection limits reflect this trend, but the linearity of the calibration curves and freedom from vaporization interferences are not degraded. Finally, the introduction of organic solvents is much easier, and better detection limits in an organic matrix are obtained at 148 MHz. These investigations have shown the utility of classifying the effects of changing torch sizes and operating frequencies by means of the r/s ratio. This provides the analyst with a means of selecting the general range of conditions to be employed in a particular analysis.
35
Yang, Suidong. "Diagnostics and modelling of an inductively coupled RF low-pressure low-temperature plasma." Thesis, n.p, 1998. http://oro.open.ac.uk/19841/.
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36
Smith, Scott Alan. "INDUCTIVELY COUPLED PLASMA ETCHING OF III-N SEMICONDUCTORS." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-05082002-162142/.
Повний текст джерелаАнотація:
The principal focus of this research was the employment of an in-house designed and constructed inductively coupled plasma (ICP) system for integrated studies pertaining to the etching rates and etching selectivity among AlN, GaN, and Al(x)Ga(1-x)N. An (ICP) system was chosen because of its high plasma density and low cost relative to other high-density plasma etching systems. The etch rates were studied as a function of ICP power, pressure, DC bias, and gas composition. The use of a mixture of 2 sccm BCl3 and 18 sccm Cl2 resulted in a maximum etch rate of 2.2 microns/min for GaN as well as nearly vertical sidewalls with proper masking. A selectivity value, i.e. the ratio of the etch rates between two materials, as high as 48 was achieved between GaN and AlN with the addition of low concentrations of O2 to a Cl2/Ar chemistry. The use of another selectivity technique, namely, low DC biases resulted in a maximum selectivity of 38. The mechanisms responsible for the GaN etching were determined by monitoring both the ion density with a Langmuir probe and the relative Cl radical density with an optical emission spectrometer. Increasing the ion density resulted in a non-linear increase in the etch rates; increasing the Cl radical density had a minim al affect on etch rate.
37
Lofthouse, Simon D. "Sample introduction into inductively coupled plasma mass spectrometry." Thesis, University of Hull, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343161.
Повний текст джерела
38
Chun, Ka-him, and 秦嘉謙. "Single-particle inductively coupled plasma atomic emission spectrometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/209488.
Повний текст джерелаАнотація:
Transient emission of a particle in inductively coupled plasma-atomic emission spectrometry (ICP-AES) depends on the fundamental processes of aerosol desolvation, particle vaporization and atomization, ionization, excitation and diffusion of the analyte. Ideally, the rate of the above processes can be determined from the evolution of the transient emission as the ion plume moves along the central channel of the ICP. However, the dimension of the ion plume is significantly smaller than the central channel. The signal-to-background and signal-to-noise ratios suffer when the entire channel is imaged. Deconvolution of the temporal profile is required to determine the emission intensity of the ion plume versus observation height. Small aperture can be used to locate the vertical emission position accurately, but the evolution of the plume emission is lost.
In this study, a double-slit method has been developed to pin-point two vertical positions of an ion plume. An ion plume travelling along the ICP central channel produces two peaks in the temporal emission profile. The temporal evolution of emission intensity can be correlated to delineate the degree of particle vaporization at the two positions. The relative widths and separation of the two peaks in a double-peak can be used to determine the analyte diffusion rate and particle velocity in the ICP, respectively.
An unicellular green algae, chlorella vulgaris, was used as the test particles. The average Mg content of the algae is equivalent to MgO particles of diameter of 265nm. The strong ionic emission at wavelength of 279.55nm was monitored using a ¼ -m monochromator equipped with a PMT detector. Method of curve fitting was used to filter out the noise with minimum distortion of the peak shape for accurate determination of peak height and peak width. The merits of curve fitting versus methods of smoothing such as moving average and Savitzky-Golay filtering will be discussed.
All transient emissions from the algal cells were detected with sufficient signal-to-noise ratio using a single-slit setup with slit height of 1mm at observation height of 18 mm above the load coil and ICP forward power of 1400 W. However, using the double-slit setup, less than half of the expected double-peaks were observed. One of the peaks in the double-peak can be below the detection limit and the double-peak is lost.
An innovative development of this study is that the relative sensitivity corresponding to the 2 slits can be varied to enhance the intensity of the weaker emission peak. The peak with insufficient signal-to-noise ratio for detection can be enhanced to a level above the limit of detection. The number of observed double-peaks in increased and the observed particles are more representative of the population.
Two types of double-peaks are categorized according to the relative intensity of the first peak to the second peak. A computer model was used to estimate the intensity ratio of the two emission peaks at different observation position of the ICP. The experimental and theoretical ratios agree generally. The theoretical ratio also shows the bias in the population sampled by the double-slit setup.published_or_final_version
Chemistry
Master
Master of Philosophy
39
Rizvi, Syed Shabbar Abbas. "Inductively coupled Ar/Clâ‚‚ plasma etching of GaN." Thesis, University of Ulster, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288895.
Повний текст джерела
40
Chen, Bing-Hung. "Inductively coupled radio-frequency discharges." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244566.
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41
Avrillaud, Gilles. "Génération et transfert sous vide de hautes puissances pulsées : conception et mise en oeuvre d'un générateur à stockage inductif de 640 kJ d'énergie stockée, associé à un commutateur à ouverture de plasma contrôlé magnétiquement." Palaiseau, Ecole polytechnique, 1998. http://www.theses.fr/1998EPXX0071.
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42
Ponce, de Leon Hill Claudia A. "INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY AND INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION SPECTROSCOPY USED IN THE DETERMINATION AND SPECIATION OF TRACE ELEMENTS." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin990645108.
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43
Ho, Koon-sing, and 何觀陞. "Single-cell analysis using inductively coupled plasma mass spectrometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hdl.handle.net/10722/196076.
Повний текст джерелаАнотація:
The technique of single-cell analysis using time-resolved inductively coupled plasma-mass spectrometry has been characterized and optimized. Determination of the metal contents of individual cells provides data on the natural metal contents of the cells and the corresponding distributions in the population. The distribution is a useful indicator of the health and the state of development of the cells. The contents of sorbed metals of individual cells over a duration of time are required to understand the dynamics of metal-cell interactions.
A green alga, Chlorella vulgaris, was used as a model biological cell in this study. The criteria and procedures for proper sampling of the cells into the ICP will be discussed. Ideally, each ICP-MS spike corresponds to one cell, but cell overlapping occurs because the cells enter the ICP randomly. Selection of cell number density and sample uptake rate to minimize spike overlapping will be discussed. A cell counting method based on the frequency of the spikes has been developed.
The distribution of the metal contents of cells was determined by measuring large number of spikes. The minimum number of spikes required was determined by statistical analysis. The spike intensity distribution was correlated with the size distribution of the cells. The peak maximum of the spike intensity distribution was used for the determination of the average metal content of the cells. The use of the peak maximum reduces errors due to spike overlapping in the measurement. Quantitative determination of the metal contents was achieved using standard particles for calibration. Errors in calibration using standard solution nebulization were discussed.
The technique was applied in the study of metal-cell interactions. Sorption of heavy metal ions (as environmental pollutants) by Chlorella vulgaris, and uptake of biometal (as nutrient) and metallodrug (as toxin) by Helicobacter pylori were studied. The technique requires simple sample preparation of removing the culture medium by filtration or centrifugation. The health state of the cells in the presence of toxic metals was related to the change in cell number density. The ratio of the FWHM of the spike intensity distributions of the sorbed metals to the natural metal contents of the cells is identified as a possible indicator of the location of the sorbed metals. The kinetics of metal sorption by the cells can be studied using a single cell culture. The method reduces errors due to uncertainties in cell number density and metal concentration in multiple samples that are required in conventional methods.
The optimal ICP-MS sampling depth of 17 elements, introduced into the ICP by conventional solution nebulization of aqueous standard solutions, has been determined. The elements were selected to represent a wide range of boiling points and ionization potentials. Boiling point of the dried residues and ionization potential of the analyte element were identified as the major factors that determine the optimal sampling position. Since dried sample solution aerosols are effectively nanoparticles, the study provides useful insight on the optimization of the operation conditions and calibration strategies for single-particle analysis using ICP-MS.published_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
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Lee, Kin-ho, and 李健豪. "Simulation of single-particle inductively coupled plasma-mass spectrometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196478.
Повний текст джерелаАнотація:
Time-resolved Inductively Coupled Plasma –Mass Spectrometry (ICP-MS) is a versatile tool for the analysis of single particles such as air particles, nanoparticles, and biological cells. In this study, the processes of particle vaporization and analyte atom diffusion and ionization in the ICP were investigated using computer simulation. Gold nanoparticles of particle diameter 10 to 250 nm were used as the model particle. The parameters of the model were optimized with respect to the experimental data. The relative importance of these parameters was investigated. Simulated ICP-MS intensity versus sampling depth for different particle size was calculated.
Two models of particle vaporization, namely heat-transfer-limited and mass-transfer-limited, were adopted to describe the kinetics of vaporization of the gold nanoparticles. The rate of particle vaporization of the limiting model in each 5-µs time step was used in the simulation. The heat-transfer-limited process dominates at lower position of the ICP. The mass-transfer-limited process takes over at sampling depth of 4mm or above where the ICP temperature is higher than 4000K. The simulation assumed that the gold atoms vaporized from the particle in each time step diffuse independently. The number density of the gold atoms was calculated using the Chapman-Enskog diffusion theory for each subsequent time step. The degree of ionization of the gold atoms was estimated using Saha equation and was assumed to be dependent on the plasma temperature only. The simulated ICP-MS intensity at any instant was the sum of the gold ions in the ion plumes from all previous time steps that pass through a 1-mm sampler cone.
The effects of several simulation parameters on the calculated ICP-MS intensity were investigated. The simulation depth profile of ICP-MS intensity of 100-nm gold nanoparticle was compared to the experimental ICP-MS depth profile. The ICP-MS intensity depends strongly on the ionization temperature of the plasma and the evaporation coefficient of the analyte. The ICP temperature profile, gas velocity, ionization temperature and evaporation coefficient were optimized for the best fit of simulated results to the experimental data.
Simulated calibration curves of gold nanoparticles of nominal diameter of 10 nm to 250 nm are non-linear at any sampling depth. The calibration curve rolls off at high mass due to incomplete vaporization of the larger particles in the ICP. The calibration curve at high sampling depth concaves upward in the low mass range because of significant diffusion loss of the analyte atoms for the small particles.published_or_final_version
Chemistry
Master
Master of Philosophy
45
Lee, Wan-waan, and 李雲鬟. "Studies of single-particle inductively coupled plasma mass spectrometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208541.
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Carpenter, Robert Christopher. "Inductively coupled plasma-optical emission spectrometry for forensic analysis." Thesis, University of Plymouth, 1985. http://hdl.handle.net/10026.1/2680.
Повний текст джерелаАнотація:
The fundamental characteristics and applications of inductively coupled plasma - optical emission spectrometry (ICP-OES) for forensic science purposes have been evaluated. Optimisation of ICP-OES for single elements using simplex techniques identified an ICP torch fitted with a wide bore injector tube as most suitable for multielement analysis because of a compact analytical region in the plasma. A suitable objective function has been proposed for multielement simplex optimisation of ICP-OES and its effectiveness has been demonstrated. The effects of easily ionisable element (EIE) interferences have been studied and an interference minimisation simplex optimisation shown to be appropriate for the location of an interference free zone. Routine, interference free determinations (<2% for 0.5% Na) have been shown to be critically dependant on the stability of the injector gas flowrate and nebuliser derived pressure pulses. Discrete nebulisation has been investigated for the analysis of small fragments of a variety of metal alloys which could be encountered in casework investigations. External contamination together with alloy inhomogeneity have been shown to present some problems in the interpretation of the data. A compact, corrosion resistant recirculating nebuliser has been constructed and evaluated for the analysis of small fragments of shotgun steels. The stable aerosol production from this nebuliser allowed a set of element lines, free from iron interferences, to be monitored with a scanning monochromator. The analysis, classification and discrimination of casework sized fragments of brasses and sheet glasses have been performed and a method has been proposed for the analysis of white household gloss paints. The determination of metal traces on hands following the handling of a variety of metal alloys has been reported. The significance of the results from these evidential materials has been assessed for forensic science purposes.
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Clarke, Philip Alexander. "Solid sample introduction in Inductively Coupled Plasma Emission Spectrometry." Thesis, Sheffield Hallam University, 1988. http://shura.shu.ac.uk/19472/.
Повний текст джерелаАнотація:
This Thesis describes the progress made in the area of solid sample introduction in Inductively Coupled Plasma Emission Spectrometry (ICP-ES). As an alternative to solution nebulisation two methods of introducing samples to the ICP are investigated. The first of these uses the direct insertion probe technique first described by Horlick and Salin (63). The assembly utilised an electrically operated graphite rod system. This could be used equally well with small volumes of solution sample (5ul) or small masses of solid sample (Ca.5mg). The variables of cup dimensions and material were investigated along with volume and masses of sample used. Results of calibration of both solution residues and solid samples are presented along with details of Limit of Detection and sample Relative Standard Deviation (RSD). The comparative data were found to be in good agreement and it was established that solutions derived calibration data could be used for the analysis of Ni-base samples. Other solid matrices, elemental and alloyed were investigated. These materials divided into two groups, (1) low volatility matrix, from which trace elements were released and only minimal emission from matrix elements was detected and there were no spectral interference effects, (2) volatile matrix in which the matrix vaporized in the same temperature range as the trace elements, giving rise to substantial matrix emission and spectral interferences. It was concluded that DI-ICP-ES is at its most useful when dealing with easily volatilized trace elements in a relatively involatile matrix. The second approach to sample introduction involved the use of an electrothermal vaporization cell. This provided precise control of temperature and offered considerably higher final temperatures than the direct insertion probe system. An Electrothermal Vaporization (ETV) device was designed and built in the laboratory and interfaced to the ICP such that vapour produced in the cell was carried into the plasma discharge by the 'injector' gas stream. ETV was used for liquid and solid samples and results for these samples are presented.
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Williams, John G. "Inductively coupled plasma mass spectrometry : analytical methodology and capability." Thesis, University of Surrey, 1989. http://epubs.surrey.ac.uk/844513/.
Повний текст джерелаАнотація:
The performance of the new analytical atomic techniques of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is assessed. A detailed examination of ICP-MS instrumentation was carried out to derive data on performance criteria such as precision, resolution, dynamic range and limits of detection. For most elements, sub ng.mL-1 limits of detection can be achieved together with a linear dynamic range of 4-5 orders of magnitude. Spectral simplicity is one of the attractions of ICP-MS; however, the technique is prone to spectral interference from polyatomic, analyte oxide and doubly charged ions. The significance of these species was studied together with methods for reducing their levels, in particular with use of a cooled spray chamber. Plasma operating parameters were found to effect system performance so a detailed examination of the effects of varying plasma operating parameters was carried out and showed that for ICP-MS systems used in this study, optimisation for maximum elemental signal response resulted in near minimal levels of interference species. Having assessed the optimum operating conditions and potential drawbacks of the technique, the final part of the study was devoted to elemental and isotope ratio determinations using conventional and 'novel' sample introduction methods. The study demonstrates that, apart from the interference problems identified, the technique of ICP-MS is a very useful addition to the field of analytical atomic spectrometry.
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Cheung, Wai-kwong Andy. "Investigation of probe insertion effects on plasma excitation conditions in direct sample insertion-inductively coupled plasma atomic emission spectrometry /." View the Table of Contents & Abstract, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31490955.
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Cheung, Wai-kwong Andy, and 張偉光. "Investigation of probe insertion effects on plasma excitation conditions in direct sample insertion-inductively coupled plasmaatomic emission spectrometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B45014747.
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