Dissertations / Theses on the topic 'Microwave plasmas'
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Burke, P. E. "A study of microwave induced plasmas." Thesis, London Metropolitan University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376442.
Full textNagai, Mikio, Masaru Hori, and Toshio Goto. "Properties of atmospheric pressure plasmas with microwave excitations for plasma processing." American Institute of Physics, 2005. http://hdl.handle.net/2237/7072.
Full textHirst, Peter Frank. "Low pressure plasmas for high power microwave sources." Thesis, University of St Andrews, 1992. http://hdl.handle.net/10023/13613.
Full textLuk, Kar Tsun. "Dry reforming in a microwave plasma /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CENG%202005%20LUK.
Full textPencheva, Mariana. "Modelling of atmospheric pressure argon plasmas: application to capacitive RF and surface microwave discharges." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209451.
Full textDoctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
du, Toit Erasmus. "Kinetic study of microwave start-up in tokamak plasmas." Thesis, University of York, 2017. http://etheses.whiterose.ac.uk/18949/.
Full textRidenti, Marco Antonio 1986. "Diagnóstico e modelagem de plasmas gerados por micro-ondas e aplicações." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/276981.
Full textTese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
Made available in DSpace on 2018-08-24T21:57:52Z (GMT). No. of bitstreams: 1 Ridenti_MarcoAntonio_D.pdf: 6265448 bytes, checksum: 384897ffe1b8b10a23a0ab7c3b206b76 (MD5) Previous issue date: 2014
Resumo: Neste trabalho plasmas não térmicos gerados em pressão atmosférica e sustentados por ondas de superfície em micro-ondas, tendo o argônio como gás de alimentação, foram estudados experimentalmente e teoricamente tendo em vista aspectos pouco compreendidos de suas propriedades físicas e aplicações voltadas ao tratamento de biomassa. Medições da composição elementar e dos parâmetros físicos foram realizados por meio de técnicas de diagnóstico baseadas em espectrometria de massa e espectroscopia óptica de emissão. O sistema físico foi modelado por meio das equações de continuidade das espécies neutras e carregadas, da equação do calor e da equação de Boltzmann dos elétrons, que foram acopladas utilizando um procedimento auto-consistente. Uma vez obtido o quadro geral das propriedades do plasma, foi estabelecida a condição de operação adequada ao tratamento das amostras derivadas de biomassa. O tratamento foi realizado sobre quatro tipo de amostras: lignina, xilana, celulose e bagaço de cana-de-açúcar. Dentre as contribuições importantes deste trabalho podem ser destacadas: (i) a verificação experimental do papel dos íons moleculares do argônio no processo de contração da descarga; (ii) a determinação do perfil axial no plasma dos principais íon positivos e negativos, da densidade e temperatura eletrônicas, da temperatura do gás e da densidade do estado metaestável Ar(1s5); (iii) verificação da seletividade do tratamento a plasma, tendo sido observada uma alteração significativa dos espectros de absorção no infravermelho nos casos da lignina e da xilana, mas não no caso da celulose. Esse último resultado sugere uma rota inusitada para novas tecnologias de deslignificação e síntese de novos materiais a partir de biomassa
Abstract: In this work non-thermal argon plasmas produced at atmospheric pressure and sustained by microwave surface waves were theoretically and experimentally studied in view of their non understood aspects and also the applications aimed at biomass treatment. Measurements of elemental composition and physical parameters were carried by means of plasma diagnostic techniques such as mass spectrometry and optical emission spectroscopy. Plasma modelling based on the self-consistent solution of the continuity equations of the neutral and charged species, the heat equation and the electron Boltzmann equation was developed to describe the plasma properties. Once a complete picture of the plasma behaviour was obtained, a promising condition for plasma treatment was established. Four types of biomass derived material were plasma treated: lignin, cellulose, xylan and sugarcane bagasse. Among the important contributions of this work one may highlight the following: (i) the experimental verification of the crucial role of argon molecular ions in the discharge contraction; (ii) axial profile determination of the main positive and negative ions, the electronic temperature and density, the gas temperature and the metastable state Ar(1s5) density; (iii) important modification of the infrared absorption spectra after plasma treatment in the cases of lignin and xylan, but not in the case of cellulose, suggesting a unexpected route for delignification and new materials synthesis from biomass
Doutorado
Física
Doutor em Ciências
Helal, Yaser H. "Submillimeter Spectroscopic Study of Semiconductor Processing Plasmas." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483396745873412.
Full textSimon, Antoine. "Étude de dispositifs de limitation de puissance microonde en technologie circuit imprimé exploitant des plasmas de décharge." Thesis, Toulouse, ISAE, 2018. http://www.theses.fr/2018ESAE0037/document.
Full textIn this project, the non-linear interactions between the high-power microwave signal and micro-discharges plasmas integrated in the microwave circuits or antennas of the transmitter (for example,Telecommunication transmitter, RADAR, ...) will be exploited to obtain its reconfigurability. Such a problem addresses a set of competences at the interface between plasma physics and microwaves. It concerns both upstream and engineering considerations. The work to be carried out during this project should make it possible to progress in two research tasks that will structure the activities of the thesis. First, the characterization of microdischarge plasmas will be perform then it will possible to identify and develop reconfigurable microwave devices
Osiac, Mariana [Verfasser]. "Spectroscopic studies of microwave plasmas containing diborane and acetylene / Mariana Osiac." Aachen : Shaker, 2003. http://d-nb.info/1172611483/34.
Full textAbdillahi, M. M. "Microwave induced plasmas for the spectrochemical determination of some non-metals." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/37912.
Full textZhu, Guo-Qiang. "Modeling of plasma dynamics and pattern formation during high pressure microwave breakdown in air." Phd thesis, Université Paul Sabatier - Toulouse III, 2012. http://tel.archives-ouvertes.fr/tel-00668934.
Full textThomas, David A. "Phased array imaging of two dimensional Doppler microwave backscattering from spherical tokamak edge plasmas." Thesis, University of York, 2016. http://etheses.whiterose.ac.uk/16885/.
Full textVas̆eková, Eva. "Spectroscopic studies of etching gases and microwave diagnostics of plasmas related to the semiconductor industry." n.p, 2006. http://physics.open.ac.uk/~ev295/!MASTER_THESIS.pdf.
Full textVasekova, Eva. "Spectroscopic studies of etching gases and microwave diagnostics of plasmas related to the semiconductor industry." Thesis, Open University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.690909.
Full textDucatte, Gerald Roger. "Aspects of the microwave induced plasma as an element selective detector for supercritical fluid chromatography and supercritical fluid extraction." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/39732.
Full textSamudrala, Gopi Krishna. "Multivariable study on homoepitaxial growth of diamond on planar and non-planar substrates." Birmingham, Ala. : University of Alabama at Birmingham, 2009. https://www.mhsl.uab.edu/dt/2009p/samudrala.pdf.
Full textTitle from PDF title page (viewed Jan. 28, 2010). Additional advisors: Shane A. Catledge, Joseph G. Harrison, Raymond G. Thompson, Uday K. Vaidya. Includes bibliographical references (p. 75-78).
Ma, Jie. "Exploration of the gas phase chemistry in microwave activated plasmas used for diamond chemical vapour deposition." Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445892.
Full textKroely, Laurent. "Process and material challenges in the high rate deposition of microcrystalline silicon thin films and solar cells by Matrix Distributed Electron Cyclotron Resonance plasma." Phd thesis, Ecole Polytechnique X, 2010. http://pastel.archives-ouvertes.fr/pastel-00550241.
Full textZhu, Yu. "Modeling of a microwave plasma electron source for neutralization of ion thrusters." Toulouse 3, 2013. http://thesesups.ups-tlse.fr/1970/.
Full textThe electron sources are used to neutralize the ion beams from the ion thrusters. The conventional neutralizers are thermoionic hollow cathodes, which are fragile, expensive and very sensitive to the contaminations, especially by Oxygen in Low Earth Orbit. Therefore, the research in seeking a plasma electron source is still very active. In my thesis, I have tried to understand the physics behind a microwave plasma electron source, by means of analytical global model and self-consistent numerical model, and compared the results with the experimental results. The first effort was devoted to better understand the plasma generation under the conditions similar to those of experiments. In particular, we found the best thresholds of gas flow rate, gas pressure and aperture size in order to trigger the breakdown. The second effort was devoted to understand how much is the maximum electron current that is available for extraction in the plasma source under the operation pressure range, and provide quantitative information on the plasma characteristics (plasma density, electron temperature, etc. . . ). We found the maximum current in this source is not very sensitive to the pressure and is around 20 mA/W. Knowing the maximum current, we based our last numerical study on the sheath theory, to tune the aperture size in order to extract all the electrons out from the plasma source. In the second and last study, both analytical and numerical tools were employed, and the results were in good agreements with those from the experiments
McCleary, Keith Alan. "Sample introduction and solvent effects in an argon and helium microwave induced plasma." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/40444.
Full textChruszez, Olivier. "Caractérisation de matériaux plasmas pour la conception de fonctions hyperfréquences." Phd thesis, Toulouse, INPT, 2015. http://oatao.univ-toulouse.fr/15662/1/CHRUSZEZ.pdf.
Full textIwai, Akinori. "Linear and Nonlinear Functions of Plasmas in Electromagnetic Metamaterials." Kyoto University, 2019. http://hdl.handle.net/2433/242471.
Full textRegnard, Guillaume. "Développement d'une nouvelle génération de plasmas micro-onde à conditions opératoires étendues." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENY060/document.
Full textThis work was done in the « Laboratoire de Physique Subatomique et de Cosmologie (IN2P3,Grenoble) » during a collaboration with Thales. The aim of the project was the development of a newgeneration of microwave plasma with extended operating conditions in the pressure range 0.5 mtorr to10 torr in argon. The presented work consists of: i) designing applicators based on sections of λ/4length serving as impedance transformers between the generator and the plasma with impedance ofgiven assumed value (approximate impedance adaptation); ii) experimentally determine the realplasma impedance (the real part and the imaginary part) for given operating conditions from themeasurement of modulus and phase of the reflection coefficient S11; iii) resize the different sections ofthe applicator by digital simulation taking the real plasma impedance into account; iv) finally, verifyexperimentally that the impedance adaptation between the generator and the plasma is correct. Theobtained results clearly demonstrate that it is possible, at a given frequency (here 2.45 GHz), to designand size a plasma source with an efficiency greater than 80 % for a window in pressure (at least onedecade) equivalent to an operating window in terms of plasma parameters. These individual sourceswith localized absorption of microwaves can be used in numbers to achieve uniform plasmas via theirdistribution over two-dimensional (planar sources) or tri-dimensional (volume plasma) networks, andthus for industrial surface treatments
Almustafa, Mohamad. "Modélisation des micro-plasmas, conception des circuits micro-ondes, Coupleur Directionnel Hybride pour Mesures et des applications en Télécommunication." Phd thesis, Toulouse, INPT, 2013. http://oatao.univ-toulouse.fr/14170/1/almustafa.pdf.
Full textBinner, Eleanor, and ebinner@iprimus com au. "Investigation of trichloroethene destruction for the degreasing industry." Swinburne University of Technology, 2005. http://adt.lib.swin.edu.au./public/adt-VSWT20051025.112548.
Full textMaho, Thomas. "Stérilisation de dispositifs médicaux ensachés par plasmas froids basse pression." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2077.
Full textStandard sterilization methods such as autoclave, ethylene oxide or irradiation can affect the biocompatibility of medical devices, especially those sensitive to heat or chemicals products. Numerous studies have demonstrated the possibility to use low pressure plasmas as an alternative sterilization process: low process temperature, treatment time competitive to autoclave and without any toxic agent. However, the sterile state preservation is still a problem. In the framework of the ANR PLAS'STER project, this CIFRE thesis focus on a new sterilization process development based on low pressure cold plasmas. The innovation resides in the creation and the confinement of a plasma inside a sterilization bag, thereby ensuring the conservation of the sterile state. The first part was dedicated to the physical characterization of the plasmas discharges confined inside the bag of sterilization. Secondly, the bactericidal efficiency of the process was demonstrated on Gram negative and Gram positive bacteria according to the EN556 standard. Additional tests on E. coli lead to hypothesis on the sterilization mechanisms and opened tracks on the optimization of our process. Finally, the properties analysis of biomaterials demonstrated the absence of macromolecular modifications and validated the potentiality of the process PLAS' STER as the sterilization method alternative
Arcese, Emanuele. "Numerical modeling of microwave plasma actuators for aerodynamic flow control." Thesis, Toulouse, ISAE, 2019. http://www.theses.fr/2019ESAE0020/document.
Full textIn recent decades, microwave discharge plasmas have attracted increasing attention of aerospace scientific community to the subject of aerodynamic flow control because of their capability of sub- stantially modifying the properties of the flow around bodies by effective energy deposition. The design and optimization of these plasma actuators as flow control technique require a compre- hensive understanding of the complex physics involved that the sole experiments are incapable to provide.In this context, we have interest in the numerical modeling of the mutual interaction of elec- tromagnetic waves with plasma and gas in order to better understand the nature of microwave discharges and their applicability. A challenging problem arises when modeling such phenomena because of the coupling of different physics and therefore the multiplicity of spatial and tempo- ral scales involved. A solution is provided by this thesis work which addresses both physics and applied mathematics questions related to microwave plasma modeling.The first part of this doctorate deals with validity matters of the physical model of microwave breakdown based on the local effective field concept. Because of large plasma density gradients, the local effective field approximation is questionable and thus a second-order plasma fluid model is developed, where the latter approximation is replaced by the local mean energy approximation. This modeling approach enables to take into account the non-locality in space of the electron energy balance that provides a more accurate description of the energy deposition by microwave plasma leading to the shock waves formation into the gas. A dimensionless analysis of the plasma fluid system is performed in order to theoretically characterize the non-locality of the introduced electron energy equation as function of the reduced electric field and wave frequency. It also discusses other approximations related to the choice and method of calculation of electron transport coefficients.Concerning the mathematical aspects, the thesis work focuses on the design and the analysis of a multiscale method for numerically solving the problem of electromagnetic wave propagation in microwave plasma. The system of interest consists of time-dependent Maxwell’s equations coupled with a momentum transfer equation for electrons. The developed approach consists of a Schwartz type domain decomposition method based on a variational formulation of the standard Yee’s scheme and using two levels of nested Cartesian grids. A local patch of finite elements is used to calculate in an iterative manner the solution in the plasma region where a better precision is required. The proposed technique enables a conservative local and dynamic refinement of the spatial mesh. The convergence behavior of the iterative resolution algorithm both in an explicit and implicit time-stepping formulation is then analyzed.In the last part of the doctorate, a series of numerical simulations of microwave breakdown and the filamentary plasma array formation in air are performed. They allow to study in detail the consequences of the different types of physical approximations adopted in the plasma fluid model. Then, these numerical experiments demonstrate the accuracy and the computational efficiency of the proposed patch correction method for the problem of interest. Lastly, a numerically investigation of the effects of gas heating on the formation and sustaining of the filamentary plasma array in atmospheric-pressure air is carried out. For doing this, the developed microwave-plasma model is coupled with unsteady Navier-Stokes equations for compressible flows. The simulations provide interesting features of the plasma array dynamics during the process of gas heating, in close agreement with experimental data
Mazières, Valentin. "Claquage microonde par retournement temporel." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30230.
Full textOne of the challenges that face plasma technologies is the development of plasma source concepts that can be scaled to larger dimensions, for example for the surface processing of large objects (solar panels, flat screens, large wafers, etc.). However, the more the area to be processed is large, the more it is difficult to process it. In fact, when increasing the area these technologies face physical and technological limitations. For microwave plasma sources, the inability to control plasmas comes from the multi-mode nature of large cavities, which makes the control of the spatial distribution of the electric field (and thus of the plasma) inside very difficult with conventional technologies. The objective of this thesis is to develop a microwave plasma source addressing this need for plasma control in large cavities (multimode). We then introduced an innovative concept of microwave plasma source: the "wave plasma brush". The principle of this plasma source consists in dynamically controlling the position of the plasma in a cavity by playing on the waveform of the transmitted signal to the cavity. The idea is then to use "Time Reversal", which allows a spatio-temporal focusing of the electromagnetic energy in large cavities.This thesis proposes the first theoretical studies and the first experimental demonstrations of the concept of "wave plasma brush"
Belapure, Jaydeep [Verfasser], Ulrich [Akademischer Betreuer] Stroth, and Peter [Akademischer Betreuer] Fierlinger. "Non-thermal electron populations in microwave heated plasmas investigated with X-ray detectors / Jaydeep Belapure. Gutachter: Peter Fierlinger ; Ulrich Stroth. Betreuer: Ulrich Stroth." München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1033891258/34.
Full textBelapure, Jaydeep Verfasser], Ulrich [Akademischer Betreuer] [Stroth, and Peter [Akademischer Betreuer] Fierlinger. "Non-thermal electron populations in microwave heated plasmas investigated with X-ray detectors / Jaydeep Belapure. Gutachter: Peter Fierlinger ; Ulrich Stroth. Betreuer: Ulrich Stroth." München : Universitätsbibliothek der TU München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20130416-1140667-0-8.
Full textGraef, Holger. "Dirac fermion optics and plasmonics in graphene microwave devices." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS624.
Full textThis thesis addresses three different phenomena in the DC and GHz electronic transport properties of ballistic, hBN-encapsulated graphene: Firstly, the total internal reflection of electrons is investigated in a gate-defined corner reflector. Both geometric and coherent electron optics effects are demonstrated and the device is shown to be sensitive to minute phonon scattering rates. It is then used as a proof-of-concept for GHz electron optics experiments in graphene, paving the way for phonon time-of-flight measurements. Secondly, we introduce top-gated graphene field-effect capacitors as a platform to study ultra-long wavelength plasmons with a vector network analyzer. We simultaneously measure resistivity, capacitance and kinetic inductance. A resonance is observed at 40 GHz, corresponding to a plasmon of 100 µm wavelength. This result sets a milestone for the realization of resonant plasmonic devices and the investigation of plasmon propagation in bipolar superlattices. Finally, we move our attention to the quantum Hall breakdown in a bilayer graphene sample. DC transport and GHz noise measurements show that the elusive intrinsic breakdown field can be reached in graphene. Its signature is an abrupt increase of noise, with a super-Poissonian Fano factor. A magnetoexciton instability is proposed as the origin of breakdown
Bockel-Macal, Savine. "Étude d'un procède de nitruration assistée par une post-décharge micro-ondes Ar-N₂-H₂ en écoulement : diagnostics de la phase gazeuse et modélisation du réacteur." Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL018N.
Full textPouvesle, Jean-Michel. "Réactivité des espèces métastables et des ions moléculaires de l'hélium dans des plasmas a pression élevée." Orléans, 1986. http://www.theses.fr/1986ORLE0216.
Full textMitschker, Felix [Verfasser], Peter [Gutachter] Awakowicz, and Anjana [Gutachter] Devi. "Influence of plasma parameters in pulsed microwave and radio frequency plasmas on the properties of gas barrier films on plastics / Felix Mitschker ; Gutachter: Peter Awakowicz, Anjana Devi ; Fakultät für Elektrotechnik und Informationstechnik." Bochum : Ruhr-Universität Bochum, 2019. http://d-nb.info/1175205095/34.
Full textKassir, Abdel Majid. "Spectres radiatifs de plasmas d'air, N2, Ar-N2-H2 à l'équilibre et en déséquilibre thermique : étude théorique et caractérisation d'une décharge micro-ondes." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30140.
Full textPlasma radiation plays an important role in many applications, ranging from surface modification to aerospace sciences. In a medium constituted of atoms and molecules, such as a plasma, the spectral emission analysis of these species allows one to calculate the medium's characteristic temperatures and electron number density. This study aims to characterize a plasma through its radiation in both thermal equilibrium and weak non-equilibrium conditions. To achieve this goal, a radiative spectra simulation code was developed to study the plasma radiation as a function of the medium's characteristic temperature(s). Additionally, a microwave plasma torch experimental setup was assembled allowing the generation of a weak non-equilibrium plasma, which was then characterized by means of optical emission spectroscopy. First, the context of this study will be positioned in respect to the literature and scientific project of the team. The physical laws governing equilibrium and non-equilibrium plasma will be detailed, and optical emission spectroscopy diagnostic methods normally used to probe these plasmas will be presented. In addition, radiative spectra simulation software, such as LIFBASE, SPECAIR, and SPARTAN, will be described at the end of the first chapter; spectra calculated via these software serve as a reference and comparison basis for the code developed for this work. The second part of this study focuses on the radiative spectra simulation of equilibrium and non-equilibrium plasmas. The theory of molecular radiation will be thoroughly reviewed, as will the diatomic molecules energy levels calculation. The selection rules allowing the radiative transitions between these states and leading to the particular structure of molecular spectra will be discussed, and the spectra simulated by our code will be compared to the reference spectra for the molecular systems of an air plasma and an argon-nitrogen-hydrogen plasma. The agreements and discrepancies noted during these comparisons will be underlined, as well as the necessity to compare the calculated spectra with experimental spectra in order to judge the validity of our model and those implemented in the software used as references. The third part of this work presents the experimental study that was led at the LAPLACE laboratory on the characterization of the radiation emitted by a microwave plasma torch operating at atmospheric pressure. The theory of microwaves propagation along a waveguide and the energy coupling efficiency between the microwaves and the plasma will be briefly reviewed. The experimental setup will then be detailed, and the physical conditions for generating and sustaining the discharge will be discussed. [...]
Salem, Rania. "Modélisation des plasmas micro-ondes utilisés pour le dépôt de diamant intrinsèque ou dopé au bore." Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCD013.
Full textThis thesis deals with modelling of high power density microware plasmas of H2/CH4 and H2/CH4/B2H6 mixtures used for growing intrinsic and boron-doped diamond films. The aim of this work is to establish chemical kinetic schemes in order to describe the gas phase composition and to manage limitations of physical models of high power density H2/CH4 and H2/CH4/B2H6 plasmas. This investigation relies on a numerical approach using different physical models (ID and 2D) as well as chemical models according to differents experimental parameters (pressures, power, gas composition). Comparisons are carried out with integrated densities of CH4, CH3, C2H2, C2H4, C2H6, B2H6 and B measured by TDLAS and OES in order to validate the models. Significant discrepancies highlight limitation of ID approach for high power density whereas the use of a 2D fluid model (Fluent based) proposes better description of transport phenomena. The chemical analysis of H2/CH4, H2/B2H6 and H2/CH4/B2H6 MW plasmas also shows a limitation of the current kinetic schemes for a wide range of operating conditions. In particular C/B mechanisms do not reproduce the strong influence of methane addition on B. At least, a numerical study of spatial composition of boron species near the substrate is compared to experimental results on doping efficiency
Guidi, Lorenzo [Verfasser], Eric [Akademischer Betreuer] Sonnendrücker, Caroline [Gutachter] Lasser, Eric [Gutachter] Sonnendrücker, and Olivier [Gutachter] Lafitte. "Scattering and reflection of microwave beams in fusion plasmas : Numerical analysis with semiclassical methods / Lorenzo Guidi ; Gutachter: Caroline Lasser, Eric Sonnendrücker, Olivier Lafitte ; Betreuer: Eric Sonnendrücker." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/1192441826/34.
Full textSoulier, Manon. "Caractérisation et optimisation d'une source plasma pour le traitement de semences dans le domaine agroalimentaire." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30278.
Full textAgri-food industry issues concern food products storage, and yields increase. Since the 1950's, intensive agriculture, chemical pesticides based, and massive irrigation are means used to confront increasing population needs. However, these practices have shown adverse effects on biodiversity and farmers health. Several studies have shown relevant results on cold plasmas fungicidal properties, action on seed germination and on chemicals degradation. A low-pressure air plasma (1 pascal) process was used and optimized for seed treatment. Seeds were placed onto a grounded grid inside an 80 liters reaction chamber exposed to two kinds of plasma. The main source was an electron cyclotron resonance microwave plasma applicator (MW-ECR). Plasma fundamental properties (emitted species, electron densities and temperatures) were measured to map the discharge. This characterization allowed to define two plasma regimes considering the injected power. High species density was generated inside the ECR area. At low-powers, species were diffused inside the plasma volume whereas by exceeding 100 W, they were carried towards the walls. The secondary source was a capacitively coupled radiofrequency plasma source (RF-CCP). The previous plasma parametric study was completed by varying the radiofrequency power. RF power greater than MW power results in higher reactive species density and a volume uniformization of plasma. These species are likely to interact with the seeds. This process efficiency in the agricultural issues of fungal contamination and seed yield optimization was established through two separate studies carried out on seeds which have been certified chemical treatment free. - Seeds represent the first step of the food production chain, constituting most of food products. Fungal contaminants have negative effects on seeds from field to consumer. They are crops spoilers, impacting production yields and food stocks. Molds, such as Fusarium spp. may produce mycotoxins during their metabolism process, responsible on health hazards (e.g. deoxynivalenol: DON or vomitoxin). Plasma discharges fungicidal properties were evaluated on bread wheat seeds (Triticum aestivum L.). Wheat seeds native fungal flora was identified before quantifying their inactivation by the plasma process. The microwave plasma process can face to the substrate matrix effect. This phenomenon was studied by comparing DON degradation onto plate glass carriers and wheat carriers. Post-treated seeds conformity for bread making was evaluated by physicochemical properties such as moisture and gluten contents. Germination yields were also evaluated in order to be consistent with a sustainable agriculture approach. [...]
Altaweel, Ayman. "Synthèse de nanostructures d'oxyde de cuivre par micro-post-décharge micro-ondes à pression atmospherique." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0059/document.
Full textOxidation of copper thin films deposited by magnetron sputtering on silicon and soda-lime glass substrates was performed by means of a microwave micro-afterglow to grow locally controlled nanostructures of copper oxide. The use of plasma discharges offers the possibility to handle oxygen atoms instead of oxygen molecules, which enable a substantial decrease in the synthesis temperature of about 100° typically. It was thus possible to grow hierarchical nanostructures made of nanowalls shaped in balls, nanowall with variable thicknesses, nanowires and nanodots of CuO. These different nanostructures forms successively and are distributed radially from the impact center of the post-discharge outwards. They grow by following parabolic growth rates that are due to a diffusion transport limitation. Outward diffusion occurs and creates a Kirkendall porosity at the substrate-copper interface. TEM analyses do not show any preferential orientation. Nanowires are either mono- or bi-cristals. Compressive (respectively tensile) stress was measured in Cu2O (respectively CuO). The grain size is larger in the center than on the edges of the treatment area. This enables the growth of nanowalls and nanowires with diameters pretty large close to the center whereas a smaller grain size on the edges leads to the formation of thinner nanowires but with higher surface density. The different existing growth models were considered to interpret these new results
Thouvenin, Amanda. "Dépôt et caractérisation de couches minces de SiCxNy.H par CVD assistée par plasma micro-ondes ECR avec précurseurs organosiliciés." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0196/document.
Full textSi, C and N based thin films are multifunctional materials with optical, electronical and mechanical properties showing great potential for photovoltaic and microelectronic applications and more. Those properties exhibit a strong dependency upon the structure of the thin film. Several goals were set for this thesis work: the development of a ECR microwave plasma assisted CVD deposition reactor using organosilicon precursors (hexamethyldisilazane or HMDSN and tetramethylsilane or TMS), the characterization of SiCN thin films deposited in this reactor, and the development of diagnosis tools suited for the analysis of the growing film. Two in situ characterization techniques have been developed. The interferential baseline extraction from FT-IR spectra enables the determination of thin film optical parameters (refractive index and thickness) in the infrared range. This diagnosis is applied as well with post-deposition analysis as with real time in situ control of the deposition process. Moreover, the development of a reflectometry diagnosis has allowed to monitor and control the deposition process in the visible range. Influence of substrate temperature, precursor flow and plasma power as well as thin film ageing has been studied. Those analyses have enabled the derivation of optimal deposition conditions leading to denser films with better oxidation resistance. Then, the variation of nitrogen concentration in the gaseous mixture has led to the synthesis of a wide variety of thin film compositions ranging from SiC to SiN like thin films with a large range of refractive index. Finally, using an innovative hybrid system coupling an ECR microwave plasma with the pulverization of a Si target, Si-richer thin films have been synthesized allowing for denser thin films with higher refractive indices owing to an increase in Si-C bonding
Laurent, Christopher. "Caractérisation expérimentale et optimisation de procédés plasma pour la décontamination de l'AMC (Contamination Moléculaire Aéroportée)." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30285.
Full textUn problème majeur en microélectronique est la contamination moléculaire aéroportée qui dégrade les substrats et les masques diminuant le rendement de production des composants. L'utilisation de boîtes de transport en polymères pour le stockage des substrats favorise la contamination moléculaire croisée entre les deux éléments. Il est alors primordial d'avoir un procédé de décontamination des boîtes efficace et rapide. Dans le cadre de cette thèse, plusieurs solutions de décontamination par plasmas ont été étudiées. Les plasmas étaient générés selon quatre couplages énergétiques en utilisant des excitations radiofréquence (13,56 MHz) et micro-onde (2,45 GHz). Ils étaient caractérisés avec une sonde de Langmuir et un spectromètre optique sous différentes conditions expérimentales. Enfin, un protocole de contamination au fluorure d'hydrogène a été développé pour évaluer et comparer l'efficacité de décontamination des procédés plasma à ceux utilisés actuellement en microélectronique
Gadonna, Katell. "Torche à plasma micro-onde à la pression atmosphérique : Transfert thermique." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00699619.
Full textAlrafei, Bachar. "Etude catalytique et cinétique de la méthanation du CO₂ en lit fixe et sous plasma micro-ondes Remarkably stable and efficient Ni and Ni-Co catalysts for CO2 methanation." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMIR17.
Full textThe aim of this thesis is the development of a CO₂ methanation process, within the power to gas framework, in order to be able to store the excess of electrical energy produced from renewable sources. For this purpose, high-performance Ni and Co catalysts have been developed and characterized by several techniques. The effect of nickel content, calcination temperature and cobalt addition was examined. The characterizations carried out have shown that nickel content and calcination temperature affect the nature of metal species present on the catalyst surface, as well as the reducibility of these species. A contrasting effect on reducibility and dispersion was found after cobalt addition. A 200 hours deactivation test was conducted with the most relevant catalysts. Then, a kinetic model taking into account thermal phenomena in the catalytic bed was processed. Finally, a process for CO₂ hydrogenation under microwave plasma has been developed and the synergistic effect between plasma and catalyst has been studied. This thesis is a multidisciplinary study of CO₂ methanation, starting with the catalyst, going through the process and modelling, and ending with the design of a plasma process
Kuete, Saa Duclair. "Synthèse de nanostructures d’oxyde de ruthénium par plasma micro-ondes en post-décharge à la pression atmosphérique." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0057/document.
Full textVarious ruthenium dioxide nanostructures were locally grown by the oxidation with an atmospheric pressure Ar-O2 microwave micro-afterglow of bulk ruthenium samples or thin films previously deposited by magnetron sputtering on silicon and silica. A special attention was paid to the distribution of the surface temperature of the sample which evolves typically between 530 K and 900 K. The use of plasma discharges allows a lowering of the temperature compared with the thermal oxidation conditions, given that molecular oxygen is excited or dissociated, which provides more reactive species such as singlet oxygen or atomic oxygen. According to the substrate used and the operating conditions, different nanostructures can be formed: lamellae separated by 20–50 nm, localized nano-sea urchins, high density of long nanowires and microcrystals. Nanostructures obtained were characterized by various techniques (electron microscopy, X-ray diffraction or secondary ion mass spectrometry). The grown RuO2 nanowires were determined to be generally single-crystalline with random crystallographic orientations. Very different growth mechanisms were observed and identified. Although it seems impossible to obtain uniformly distributed nanostructures on bulk ruthenium substrates, it is possible from substrates coated by a thin layer of ruthenium, which allows the formation of nanowire carpet. The possibility to localize the growth of nanowires by adding alkali salts has been studied. However, if the use of NaCl or KCl crystals locally enhances the nanowire density, they do not ensure systematically the growth of nanowires
Imam, Abdallah. "Élaboration de nanostructures d’oxydes métalliques par post-décharge micro-ondes pour la photolyse de l’eau." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0312/document.
Full textIn this manuscript, metallic oxide nanostructures were synthesized by the oxidation of iron, iron-copper and copper-zinc thin films by means of a plasma afterglow. Thin films were deposited by magnetron sputtering. The use of plasma afterglows allows a lowering of the temperature compared with the thermal oxidation conditions, given that molecular oxygen is excited or dissociated, which provides more reactive species such as singlet oxygen or atomic oxygen. This oxidation at moderate temperature promotes anisotropic crystal growth. The oxidation of iron–copper thin films leads to the synthesis of Fe2O3 nanoblades and CuO nanowalls, nanotowers and nanowires. The surface distribution of these nanostructures depends on the oxidation temperature, the concentration of the reactive species and the initial composition of the thin layers. The oxidation of copper-zinc thin films leads to the synthesis of ultra-thin ZnO nanowires in which quantum confinement could occur. As-grown nanostructures were characterized by various techniques (electron microscopy, X-ray diffraction and secondary ion mass spectrometry). The growth mechanisms described for these nanostructures relies on the role of stress, temperature, reactive species concentration and on the effect of underlying grain size. As-synthesized nanostructures will serve as photocatalysts to produce hydrogen by water splitting. In addition, ultra-thin ZnO nanowires will also serve as photocatalysts for water purification
Salman, Salman. "Reconfigurable microwave semiconductor plasma antenna." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/16290/.
Full textMoh, Sarfaraz. "Microwave assisted sputtered coatings." Thesis, University of the West of Scotland, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556071.
Full textPlujat, Beatrice. "Etude des interactions plasma/surface pour la compréhension de la croissance de couches minces SiCN : H et leur interface film/substrat : répercussions sur leurs propriétés." Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0019/document.
Full textSiNOC:H Thin-films, due to their stoichiometric flexibility, present a wide range of properties and are now used industrially in numerous applications: microelectronics, photovoltaics, mechanics, etc. We have here chosen to focus more particularly onhydrogenated silicon carbonitride SiNC:H deposited by microwave PECVD from the liquid organosilicon precursor Tetramethylsilane (TMS). The aim is to propose analternative to the use of silane pyrophoric gas currently used to deposit such materials in industrial PECVD Low Frequency/low deposition rates plasma processes. Decomposition of Ar/TMS/NH3 in the plasma phase, and resulting properties of deposited thin films are studied and correlated. Particular attention is paid to the early stages of films growth and to the study of film/substrate interface
Clem, William Charles. "Mesenchymal stem cell interaction with nanonstructured biomaterials for orthopaedic applications." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2009r/clem.pdf.
Full textAdditional advisors: Yogesh K. Vohra, Xu Feng, Jack E. Lemons, Timothy M. Wick. Description based on contents viewed July 8, 2009; title from PDF t.p. Includes bibliographical references.