Дисертації з теми "Plasma froid atmosphérique"
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Cosimi, Julien. "Caractérisations d'un jet de plasma froid d'hélium à pression atmosphérique." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30136.
Повний текст джерелаCold atmospheric pressure plasma jets are a subject of great interest in many biomedical fields for the past decade. In the various applications of these jets, the plasma generated can interact with many types of surfaces. Plasma jets influence the treated surfaces, but it is now well known that the treated surface also influences the plasma according to their characteristics. The work carried out in this thesis therefore aims to characterize a cold helium atmospheric pressure plasma jet in contact with three surfaces (dielectric, metallic and ultrapure water) by means of different electrical and optical diagnostics in order to understand the influence of the nature of the surfaces on the physical properties of the plasma and the chemical species generated. The first part of this thesis is focused on the study of the influence of surfaces on the plasma jet. Different parameters are studied, such as the nature of treated surfaces, the gas flow, the distance between the outlet of the device and the surface or the composition of the injected gas. For this purpose, helium flow at the outlet of the device is followed by Schlieren imagery with and without the discharge. Emission spectroscopy is used to determine the emissive species generated by the plasma. ICCD imagery is employed to follow the generation and the propagation of the discharge and the distribution of several excited species in the jet by using band-pass interference filters. A dielectric target causes the ionization wave to spread over its surface and a conductive target leads to the formation of a conduction channel. The evolution of excited species densities (OH*, N2*, He* and O*) increases with the relative permittivity of the treated surface. As well known, active species generated by plasma jets play a fundamental role in the kinetics and the chemistry of the mechanisms linked to plasma processes. The second part of the present work therefore relates to the spatial and temporal evaluation of the densities of the hydroxyl radical OH which plays a major role in many cellular mechanisms. The spatial mapping and the temporal evolution of the absolute and relative densities of OH are obtained by LIF and PLIF laser diagnostics. The density of OH generated increases with the electrical conductivity of the treated surface. It can be noted that the OH molecules remain present in the helium channel between two consecutive discharges (several tens of microseconds). Finally, we focus on the production of chemical species in ultrapure water treated with plasma. The influence of different parameters on the concentration of species in the treated water has been studied to optimize the production of chemical species. In experimental conditions, grounding the ultrapure water during treatment increases the concentration of H2O2. Furthermore, the grounding induces a decrease in the NO2- concentration
Hamze, Hassan. "Dépôt d’oxydes métalliques sur verre par plasma froid à pression atmosphérique." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10027.
Повний текст джерелаThe objective of this thesis is to develop and characterize the deposition of thin metal oxides based on silicon and tin by an atmospheric pressure cold plasma to improve properties of glass materials and find an ecological alternative to existing processes. This research is divided into three main parts: the first part consists in depositing from Hexamethyldisilan and Hexamethyldisiloxan thin films of SiO2/SiOxCy on soda-lime glass to improve its mechanical strength. The second part consists in depositing a thin layer of SnO2 on fluorosilicate glass from Tetrabutyltin and Tributyltin Oxide to develop an environmental friendly alternative to the current chemical vapor deposition process used in glass industry. Finally, the silicium and tin based deposits obtained are used in the third part to stop corrosion surface of fluorosilicate glasses. In parallel, the physicochemical properties of these thin films will be characterized with advanced technologies in order to optimize the deposits
Larbre, Juliette. "Décontamination de surface par un procédé plasma froid à pression atmosphérique." Paris 11, 2006. http://www.theses.fr/2006PA112134.
Повний текст джерелаThe aim of the study is to find a solution for surface decontamination. The project, build with a firm, was based on cold plasma physic using dielectric barrier discharge at atmospheric pressure. Microorganisms to kill are placed in the post-discharge with gas flow above 10 L/min. Two kinds of bacteria were tested (Corynebacterium glutamicum and spores of Bacillus subtilis) and some treatment conditions were changed: gas flow, relative humidity, surface humidity and temperature. Best performances show a high efficacy (4 log decrease in 5 minutes). From these good results we try to understand mechanisms which kill bacteria. The document discuss on three topics: plasma reactors (structure and electrical properties), gas phase chemistry and biological results
Savin, de Larclause Isabelle. "Dépôt organosilicie par plasma froid basse pression et pression atmosphérique sur substrats microstructurés." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/870/.
Повний текст джерелаThis PhD works is part of an industrial project on ophthalmic optic, developed by the company Essilor. The aim is to prepare a technological step in the apprehension of the optical function of the glass and in their production. The innovative idea is based on the introduction of some actives functions in the glass, thanks to its discretisation. To do so, Essilor turns toward the microlectronic technologies, and especially the plasma technologies. The thematic treated here is the deposition of a thin film by plasma on a microstructurated substrate. In order to obtain a quality of the film homogeneous on the whole microstructure, the coating must be conformal, i. E. It must have a thickness, composition and structure constant on all the microstructure parts. Thus, the issue of this PhD is the understanding of the mechanisms which control this property, through the use of two different processes, a microwave ECR low pressure plasma and an Atmospheric Pressure Townsend discharge. The effect of process parameters (power, substrate polarisation, temperature, gas mixture) on the conformity was studied. This allowed checking the significance of the shadow effect at low pressure and to bring out the main role of the ions. At atmospheric pressure, although mean free pass is lower compared to the microstructure size, the coating is mainly concentrated on the superior regions of the microstructure. In order to understand this phenomena, reactive mass transfer simulation and electrical field simulation was done. The diffusion seems to be responsible, and these effects are accentuated by the repartition of the electrical field at the surface. The predominance of one of these phenomena (diffusion or field effect) changes in function of the process conditions
Panousis, Emmanouïl. "Réalisation et optimisation d'un réacteur plasma froid fonctionnant à pression atmosphérique : application aux traitements de surfaces." Pau, 2006. http://www.theses.fr/2006PAUU3027.
Повний текст джерелаA dielectric barrier discharge (DBD) in Nitrogen at atmospheric pressure was the object of this work. The aim was primarily to gain insight to the physico-chemical mechanisms governing such a discharge and to also apply this configuration to the surface treatment of metals. Here, the surface treatment takes place in spatial afterglow conditions. The discharge products (active species in particular) are blown out of the inter-electrode space due to the special plasma reactors' geometry and the high gas flow. This enables the treatment of large areas and hollow objects and could easily be used in an industrial production line. The surfaces of Al-2024 and TiA6V4 metal alloys were treated during this work in an effort to render them compatible to applications involving adhesion. This work is thus composed of 3 main parts: - Numerical modeling of the DBD: results here obtained permit to qualitatively describe the discharge's electrodynamical behavior and estimate its yield in the production of active species. - Experimental study of the DBD and the afterglow: electrical diagnostic techniques were used in order to compare the two reactors studied. Optical diagnostics were then applied that helped identify the active species produced by the DBD and “follow” them in the flowing afterglow in two different configurations: the unguided and the quartz tube guided afterglow. The dominant physico-chemical mechanisms for the active species were thus identified for these conditions. - Application of the DBD in the treatment of metallic surfaces in afterglow conditions: By macroscopic and microscopic means of surface characterization it was observed that the DBD flowing afterglow were studied induces a cleaning of organic contaminants of the surface as well a possible partial de-oxidation
Bres, Lucie. "Interaction entre un plasma froid à la pression atmosphérique et des surfaces thermoplastiques industrielles : application à l'activation de surface." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30273/document.
Повний текст джерелаCarbon Fiber Reinforced Polymer (CFRP) using thermoplastic polymer matrices as Poly-EtherEtherKetone (PEEK) for example, are increasingly being used in structural engineering due to their light weight coupled with good mechanical properties. In aeronautic industry, the adhesive bonding of these composites is often required. However, their low surface energy motivates the development of robust and reliable surface activation treatments aiming at increasing the surface reactivity before painting. For this reason, we have used an atmospheric pressure plasma torch developed by AcXys Technologies(r). It is a remote plasma, well known to be an effective process to improve surface reactivity without deterioration of the bulk matrix properties. This easily implementable technology attracts many industries looking for a cost-effective and eco-friendly surface activation process. The aim of this work is to contribute to the understanding of plasma activation mechanisms leading to a greater and a more durable adhesion between PEEK matrix and an industrial painting. This study provides some insight into the effects of process parameters (device power, distance between nozzle and substrate, etc) on adhesion improvement. Mechanisms which are attributed to it are investigated by means of three point bending and crosscut adhesion standard tests. Results are discussed with respect to surface properties characterized by wettability measurements including acid-base approach, X-ray Photoelectrons Spectroscopy and Atomic Force Microscopy. In order to facilitate industrialization of atmospheric pressure remote plasma as surface activation technique, this study proposes a new approach aiming at allowing a better and more equitable comparison between atmospheric pressure plasma processes. This comparison is made through the "plasma dose" expression, similar to the one commonly used in Corona process. It is applicable for one plasma gas and accounts for both received energy and interaction time of the post-discharge with the surface. Mechanisms assigned to improvement of adhesion will be more appreciated and their characterization will contribute to a greater definition of industrial surface preparation range by remote plasma
Le, Delliou Pierre. "Étude des décharges électriques impulsionnelles à pression atmosphérique dans les milieux poreux et/ou alvéolaires." Phd thesis, Université Paris Sud - Paris XI, 2014. http://tel.archives-ouvertes.fr/tel-01062681.
Повний текст джерелаLimam, Soukayna. "La bio décontamination de surface par plasma froid : Contribution par l’étude de procédés de traitement de surface à pression atmosphérique." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC106.
Повний текст джерелаNon thermal plasma technologies have recently been receiving attention as an alternative technology for surface decontamination of thermally sensitive medical materials. This work focuses on two atmospheric pressure discharges. Bacteria exposure (contaminated samples with Escherichia coli and Bacillus stearothermophilus ) and spectroscopic measurements were made simultaneously
Bafoil, Maxime. "Stimulation de la germination des graines et de la croissance des plantes par plasmas froids à la pression atmosphérique." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30208.
Повний текст джерелаThis work is part of the convergence of the fields of plasma physics and plant biology. The objective of this thesis is to contribute answers to the mechanisms involved in the effects of cold plasmas at atmospheric pressure on the germination and development of plants. The plant model in plant biology Arabidopsis thaliana is used; by considering the reference genotype Col-0 and several of its mutants (gl2 and gpat5) in order to better highlight the effect of plasma, in particular on osmotic and saline stresses. For the direct treatment of seeds to promote germination, air plasmas are used. Indirect treatment for growth stimulation uses plasma-activated water (PAW) thanks to helium plasma jets. The results show a positive effect of the plasma treatment of air generated by a dielectric barrier discharge device on a floating electrode (FE-DBD) and also a corona device in ambient air. These direct treatments allow an increase in the germination rate but above all an increase in the speed of germination. Analysis of the seed permeability revealed a change in the seed surface due to a physical effect of the plasma on the surface. Analysis of the surface residues shows a change in lipid composition. This being strongly correlated with germination; these results allow the identification of an understanding track of the effects of plasmas on the germination of seeds. In a second part, the indirect treatment of plants with PAW has the effect of increasing the growth rate. The plasma creating a certain number of reactive species of oxygen and nitrogen (in particular nitrates and nitrites) acts as a fertilizer stimulating the growth of plants
Pavy, Allan. "Mécanismes cellulaires adaptatifs du microenvironnement tumoral exposé au plasma froid - Application au traitement du cholangiocarcinome." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS267.
Повний текст джерелаCholangiocarcinoma (CCA) is a cancer with a poor prognosis and limited therapeutic options. Surgical resection is the only curative option available, but it is applicable to only a small number of patients and offers relatively low survival rates (5-year survival of 30%) due to the typically late diagnosis of this cancer. Palliative therapies, based on chemotherapy and immunotherapy, are generally ineffective, mainly because of the desmoplastic nature of CCA, which limits the entry of drugs into the tumor site. With an increasing incidence and accounting for 2% of global cancer mortality, it is crucial to develop new therapies, including local treatments targeting tumor cells and their microenvironment, for the treatment of this cancer. It is in this context that enthusiasm for the use of cold atmospheric plasma (CAP) in the treatment of CCA has emerged. Considered the fourth state of matter and generated by the partial ionization of a gas at low temperature, CAP has demonstrated promising antitumor effects in various preclinical cancer models over the past fifteen years. It is indeed capable of producing reactive oxygen and nitrogen species (RONS). A close collaboration between the Saint-Antoine Research Center (CRSA) and the Plasma Physics Laboratory (LPP) has highlighted significant antitumor effects in an immunodeficient murine model of CCA, as well as significant remodeling of the tumor stroma, a crucial element in tumor progression. Since then, a CAP device adapted for insertion into a duodenoscope has been developed, with the aim of enabling in situ treatment of CCA tumors via endoscopy in the future. The objective of this thesis was to explore the antitumor effects of this new plasma source on in vitro and in vivo models of CCA, distinguishing the direct effects of plasma on tumor cells from indirect effects on tumorigenesis, mediated by phenotypic modifications of stromal cells, including cancer-associated fibroblasts (CAFs) and tumor endothelial cells (TECs). After demonstrating the technical feasibility and biological applicability of this endoscopic source, it was observed that the oxidative stress induced by CAP altered the activation state and migratory phenotype of CAFs, while affecting the viability and angiogenic profile of TECs. The use of three-dimensional spheroid models also revealed immunogenic signatures triggered by cold plasma treatment. Indeed, it was proven in vivo, through prophylactic vaccination, that CAP could induce immunogenic cell death (ICD) of tumor cells, promoting the recruitment of immune cells to the tumor site. Preliminary results also showed that direct treatment of subcutaneous tumors slowed tumor growth while allowing the recruitment of antitumor immune cells. Finally, after elucidating the mechanisms of ICD in vitro, a new therapeutic approach combining CAP and vaccinations was proposed, demonstrating an antitumor effect accompanied by increased infiltration of immune cells. To make the use of CAP clinically accessible, tests on porcine models were conducted to verify the thermal and electrical safety of this endoscopic source, both for the patient and the clinician. Thus, CAP opens up promising new perspectives for the locoregional treatment of CCA, by modulating the immunogenicity of tumors and impacting their desmoplastic stroma
Jidenko, Nicolas. "Caractérisation électrique et couplages électro-thermiques des décharges à barrières diélectriques dans l'air à pression atmosphérique : faisabilité de l'électrofiltration d'aérosol." Paris 11, 2004. http://www.theses.fr/2004PA112328.
Повний текст джерелаDebrabandere, Delphine. "Dépôt de couches minces par plasma froid à pression atmosphérique: application aux dépôts de SiOxCyNzHw et de TiOx." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209791.
Повний текст джерелаDans la première partie de ce travail, l’influence de l’ajout d’un gaz réactif (hydrogène ou ammoniac) dans un plasma d’azote généré avec une torche commerciale de type décharge à barrière diélectrique (DBD) est étudiée par spectroscopie d’émission optique et par des mesures simultanées de courant et tension. En particulier, des émissions de CN sont visibles dans les spectres optiques d’un plasma d’azote seul, mais ne le sont plus si un gaz réactif est ajouté. Par contre, avec de l’hydrogène ou de l’ammoniac dans le plasma, la présence de NH est détectée. Quelle que soit la nature du gaz, la décharge est filamentaire. L’ajout d’un gaz réactif permet de réduire la tension à appliquer pour maintenir la décharge.
Dans la deuxième partie, cette torche est utilisée pour déposer des couches à partir de précurseurs organosiliciés (hexaméthyldisiloxane et hexaméthyldisilazane) par plasma d’azote seul, avec hydrogène ou avec ammoniac dans une cuve industrielle mise sous azote. Diverses géométries d’injection du précurseur sont testées. L’une d’elles est choisie pour étudier les propriétés des dépôts sur de larges surfaces (de silicium pour diverses analyses et d’acier pour évaluer la résistance à la corrosion). Les dépôts par plasma d’azote seul sont de type polysiloxane. Ceux obtenus par plasma d’azote avec hydrogène contiennent moins d’azote et de carbone. Ceux réalisés par plasma d’azote avec ammoniac sont poudreux.
Dans la dernière partie, des couches d’oxyde de titane sont déposées à partir d’isopropoxyde de titane avec une torche commerciale radiofréquencée dans l’air ambiant, une décharge à barrière diélectrique à électrodes planes parallèles sous hélium à basse pression développée à l’ULB et la torche utilisée pour les dépôts à base de silicium dans une cuve de laboratoire sous azote. Les couches déposées avec la torche de type DBD sous azote contiennent de l’azote et du carbone contrairement à celles obtenues avec les deux autres installations. Ces essais ont mis en évidence la forte réactivité du précurseur avec l’humidité ambiante.
Les couches à base de silicium déposées apportent un effet barrière contre la corrosion. La résistance à la corrosion des dépôts d’oxyde de titane n’a pas encore été testée. Toutefois, dans les conditions actuelles, avec les géométries des équipements plasma utilisés, les vitesses de dépôt sont insuffisantes pour des applications en sidérurgie. D’autres géométries devraient être testées pour accroître les vitesses de dépôt.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Mericam, bourdet Nicolas. "Recherche d'optimisation énergétique d'un réacteur plasma froid de traitement d'effluents gazeux chargés en composés organiques volatils à pression atmosphérique." Phd thesis, Supélec, 2012. http://tel.archives-ouvertes.fr/tel-00765461.
Повний текст джерелаMathon, Rémi. "Décharge à Barrières Diélectriques à pression atmosphérique pour la charge bipolaire d’aérosol." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS261/document.
Повний текст джерелаThe measurement of the size distribution of an aerosol (solid or liquid particles in suspension in agas) by electrical mobility analyses requires the neutralization of the aerosol. Neutralization consistsin imparting a charge distribution with a mean charge of 0 by the diffusion of bipolar ions on aerosol.We prove the feasibility of a post- Dielectric Barrier Discharge (DBD) bipolar charger as an alternativeto radioactive neutralizer subjected to legislative constraints. The electrical characterization of awire-to-wire DBD versus the gap, the voltage and the flow-rate highlights 3 kinds of selforganizationsof filaments versus voltage. Moreover, discharge current which represents the chargedspecies production per unit of time is evaluated. In the chosen geometry and operating conditions, apost-discharge ions flux measurement method was developed. We confirm that anelectro-hydrodynamic competition controls the extraction of ions from the gap. In fact, electric fieldsand transit time control positive and negative ions densities and the ratio between them which arecritical for aerosol charging. For the post-DBD charger, ions densities decrease in the charging zone.However, this decrease does not affect the aerosol charge distribution for each particle size withconcentration. In these conditions, the post-radioactive neutralizer and post-DBD neutralizer aerosolsize measurements are compared in order to prove that the post-DBD neutralizer is available forsubmicronic aerosols sizing
Coduti, Giovanni Antonio Coduti. "Etude de l'interaction d'une onde électromagnétique avec un plasma d'air à température ambiante." Paris 11, 2005. http://www.theses.fr/2005PA112016.
Повний текст джерелаWe indicate under the name of radar a system which illuminates a portion space with an electromagnetic wave and receives waves reflected by objects which are there. It makes it possible to detect their existence and to determine characteristics of these objects. Measurements of Radar Cross Section (RCS) carried out with ONERA show that the air intake behaves as reflectors which reflect waves radars in their direction of incidence. During this study, a number of processes was explored for the SER reduction of aircraft starting from electric discharges in flows of air around atmospheric pressure. Absorption calculs of a wave EM by a homogeneous plasma shows the importance of electrons number Ne necessary for a significant attenuation in the ionized ambient air. However, the maintenance of free electrons proves to be difficult in a mixture N2 - O2 (vibrationel excitation of molecule N2 by electrons and electronic attachment on the molecule O2). Only detachment of negative ions O2- by excited oxygen O2(a1Dg) produced in the discharge could be likely to maintain a density electronic of about 1012 cm-3. Lastly, stability problems of the electric discharges still limit the use of air plasmas for the furtivity a high pressure. However, two types of discharges likely to overcome these disadvantages were put in evidence: glow discharge negative point - plan (NPP) and discharge a dynamic regulation (DDR)
Sarron, Vanessa. "Etude et optimisation d'une décharge "Plasma Gun" à pression atmosphérique, pour des applications biomédicales." Thesis, Orléans, 2013. http://www.theses.fr/2013ORLE2083/document.
Повний текст джерелаThe use of plasmas, thermic or low pressure, in biomedical goes back up to 1970s. During these last years, atmospheric pressure cold plasma jets have been developed, allowed an increase of biomedical applications of plasmas. In GREMI, a plasma jet was developed : the Plasma Gun (PG). The plasma generated by the PG propagates on long distances inside capillaries. The optimization of the aimed treatments requires a detailed study of the discharges created by the PG. The characterization of the PG highlights the generation of Pulsed Atmospheric pressure Plasma Streams or PAPS, these last ones propagating from the reactor to the capillary outlet (ambient air) where they generate a plasma plume. These PAPS present two propagation modes, during which a connection between the ionization front and the reactor is present permanently. These two modes named respectively Wall-hugging and Homogeneous, differ mainly by the morphology and their propagation velocity. These modes have common characteristics, such as the possibility of division or meeting of PAPS, as well as the transfer of PAPS through a dielectric barrier or via a hollow metal capillary. The study of the plasma plume underlined the importance of the length of capillaries on the length of the plasma jet. Furthermore, the generation of the plasma has a very strong influence on the gas flow and the jet structuration during air expansion
Mraihi, Abderrahmane. "Réalisation, caractérisation et bilan énergétique de réacteurs corona mono et multi-pointes dans l'air à la pression atmosphérique pour application à la décontamination." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1825/.
Повний текст джерелаThe aim is the realization and the characterization of corona discharge reactor especially in pulsed and positive polarity in the case of multi-tips/plan configuration for applications in chemical and biological decontaminations
Hardy, Jean-Michel, and Jean-Michel Hardy. "Modifications chimiques de la surface de l'épinette noire à la suite d'un traitement par plasma froid d'azote et d'oxygène à la pression atmosphérique." Master's thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/26496.
Повний текст джерелаL’utilisation des plasmas dans le domaine du traitement de surface est de plus en plus répandue, en particulier pour améliorer l’adhérence d’un système revêtement-substrat. Après s’être retrouvés chez les polymères synthétiques, les traitements assistés par plasma ont fait progressivement leur apparition dans le domaine du bois afin de répondre aux besoins de l’industrie forestière qui utilise les revêtements et les adhésifs. Bien que plusieurs travaux de recherche ont pu démontrer le potentiel des plasmas pour ces industries, la physique et la chimie gouvernant l’interaction plasma-bois ainsi que son rôle sur les propriétés d’adhérence demeure embryonnaire. Ce projet de maîtrise démontre que les traitements plasmas DBD à la pression atmosphérique modifient la surface du bois selon divers mécanismes tels que le mouvement d’extractibles en surface, la fonctionnalisation chimique ainsi le greffage de radicaux libre.
Whiteley, Amelia Jane. "Ingénierie de surfaces antimicrobiennes : combinaison de topographie et de fonctionnalisation par dépôt chimique en phase vapeur par polymérisation amorcée in situ et plasma atmosphérique froid." Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALI043.
Повний текст джерелаAs biofilms continue to cause damage in many different industries, leading to health issues, device failure and numerous costs, the traditional strategies used to fight against biofouling are being questioned. Indeed, the rise of antibioresistance and concerns over the toxicity of other biocides bring to light the limits of such approaches. Rather than focusing on eliminating biofilm, bioinspired strategies suggest limiting the initial bacterial adsorption by developing hydrophobic or hydrophilic surfaces. In this thesis, hydrophobic fluorine-free organosilicate thin films were deposited using two innovative deposition methods: Dielectric Barrier Discharge Cold Atmospheric Plasma (DBD-CAP) and initiated Chemical Vapour Deposition (iCVD), respectively leading to plasma polymers and conventional polymers. iCVD was also used to functionalise surfaces with superhydrophilic poly(vinylpyrrolidone). While the latter had interesting wettability properties, it’s solubility made it an impossible coating for devices to be found in bacterial suspensions or other liquid media. To overcome this, the organosilicate precursor was used as a crosslinking agent and both monomers were simultaneously injected into the iCVD reactor, creating hydrophilic and insoluble copolymers. As well as depositing these polymers on planar surfaces, they were used to coat substrates with microscale topography brought by nanoimprint lithography, and roughness achieved by plasma etching. Indeed, it has previously been shown in the literature that there are many advantages in combining chemistry and topography for antibiofouling surfaces. Finally, the developed surfaces were incubated with bacterial suspensions to assess their influence of bacterial adhesion
Odic, Emmanuel. "Propriétés physicochimiques de décharges électriques à pression atmosphérique. Application à la décontamination biologique de surface." Habilitation à diriger des recherches, Université Paris Sud - Paris XI, 2008. http://tel.archives-ouvertes.fr/tel-00351504.
Повний текст джерелаRedolfi, Michaël. "Etude de l' Oxydation de différents types d'hydrocarbures par des procédés utilisant des techniques de déharges électriques non- thermiques à pression atmosphérique: application à la problématique du démarrage à froid." Phd thesis, Université Paris-Nord - Paris XIII, 2007. http://tel.archives-ouvertes.fr/tel-00358147.
Повний текст джерелаJudée, Florian. "Liquides activés par jet de plasma froid pour le traitement sélectif du cancer colorectal : synthèse, caractérisation et essais thérapeutiques sur modèles cellulaires 3D in vitro et in vivo." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30344/document.
Повний текст джерелаPlasma devices at atmospheric pressure (AP) generate many physical active species (photons, charged particles, electric field, etc.) and chemical (free radicals, reactive oxygen species, reactive nitrogen species, etc...). This species are well known for their direct or indirect biological effects thus biomedical treatment by low temperature plasma jets at AP is currently a hot research topic. The upsurge of radioresistance and chemoresistance of microorganisms and cancer cells requires the development of new biomedical treatment. In this general context, the present work is a step towards the understanding of the effect induced by low temperature plasma jets at atmospheric pressure on colorectal cancer (second leading cause of death by cancer in France). This thesis focuses on the implementation of an in vitro biological model (multicellular tumor spheroid of colorectal cancer HCT116) in 3 dimensions which allows to take into account key parameters in tumor proliferation. This model is also well suited for the prediction of in vivo results in the aim of a subsequent clinical study. Further research about kinetic reactions of active species has been studied from the plasma device up to intracellular interactions through physical, biological and chemical analyses. Indirect treatment of tumors was carried out through helium plasma jet activated liquids. This solution was chosen for its relevance for endoscopic treatment of colorectal cancer. Interaction between plasma activated liquid and multicellular tumor spheroids has shown two distinct pathways. The first one is the genotoxicity of activated medium induced by the occurrence of hydrogen peroxide which induced DNA damages once penetrated in intracellular medium and leading to cell death by apoptosis. A direct interaction between free radicals generated in liquid medium and the latter components (amino acids, glucose, etc.) associated with the occurrence of nitrites and nitrates induces a long-term antiproliferative effect of plasma activated liquid. Chemical pathways of the formation of these active species were identified by using different analysis techniques such as electron paramagnetic resonance and optical emission spectroscopy. Therapeutic analysis have also demonstrated that plasma activated liquid damage preferentially colon cancer cells rather than healthy cells making it a particularly promising selective treatment method. The design and the characterization of a second plasma jet using argon as a carrier gas was carried out with the aim to improve the antiproliferative effect of plasmas on tumors while taking into account the requirement for the use of such device for colorectal cancer treatment
Amorosi, Cédric. "Polymérisation par plasma froid : un outil pour l'obtention de surfaces fonctionnalisées pour les applications de type biocapteur et pour les systèmes à libération de médicaments." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00864105.
Повний текст джерелаChauvin, Julie. "Etude des mécanismes anti-cancéreux induits par milieux activés par jet de plasma froid : vers une nouvelle approche thérapeutique." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30263/document.
Повний текст джерелаCancer therapies based on physical principles (radiofrequency, ultrasound, laser, electroporation...) have considerably increased in the last decade. Their objectives are to directly destroy cancer cells, to favor the targeted entry of therapeutic molecules or to stimulate the patient's immune system in order to eliminate the tumor. Cold plasma still arouses interest in the field of oncology through its ability to generate reactive oxygen species (ROS) and nitrogen species (RNS) which can be genotoxic and cytotoxic for cancer cells. Two approaches to the use of plasma are studied: either direct exposure of cells to the plasma jet, or indirect exposure via the use of a Plasma Activated Medium (PAM). The PAM being easier to deliver by injection into the tumor, this approach was chosen in this work. The work presented consists in studying the genotoxic and cytotoxic effects of PAM resulting from exposure of the medium to the helium plasma jet on in vitro and in vivo tumors. For in vitro studies, we chose to use a 3D model: the spheroid (MCTS - MultiCellular Tumor Spheroid). This model has similar characteristics to the in vivo model thanks to its spheroidal organization. The spheroids have indeed gradients of oxygen penetration, nutrients and cell proliferation. The first part of the thesis concerns the identification and quantification of the species generated in PAM. The analytical methods used are paramagnetic electronic resonance, fluorimetry, colorimetry, liquid chromatography and mass spectrometry. These analyses revealed that the toxicity of PAM was due to several factors: on the one hand to the generation of ROS and RNS and on the other hand to the degradation of cell nutrients contained in the medium via, for example, the oxidation and nitrosylation of the amino acids. The second part is dedicated to the study of the effects of PAM on HCT-116 (colon cancer) spheroids[...]
Darny, Thibault. "Etude de la production des espèces réactives de l’oxygène et de l’azote par décharge Plasma Gun à pression atmosphérique pour des applications biomédicales." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2086/document.
Повний текст джерелаOver the past ten years, the cold atmospheric pressure plasma jets (CAPPJ) became useful devices for biomedical applications. Their relatively simple design and use, combine with their ability to produce reactive species (NO, OH, O, …), led to a rapid research growth in this field. A lot of studies have been devoted to quantitative diagnostics development for the reactive species production measurements in the plasma plume. However, it is difficult to compare one jet with another because of the huge variety of discharge geometries, electric power supplies or operating conditions. This thesis deals with the study of the CAPPJ developed in GREMI, the Plasma Gun (helium feeded, microsecond voltage pulse). We have studied discharge mechanisms which strongly impact the reactive species production in near target biomedical application conditions. This study is divided in three parts : the study of helium flow modifications induced by the plasma (strioscopy visualization); the study of plasma propagation inside dielectric capillary (experimental and numerical study of fast plasma propagation dynamic and electric field evolution for helium-nitrogen mixtures); the study of conductive target-plasma interaction (space and time resolved measurements inside the capillary and the plasma plume of helium metastable production, correlated with electric field evolution). The conductive target contact concerns any in vivo biomedical treatments. CAPPJ in front of such a conductive target leads to fundamentally different discharge mechanisms compare to the free jet case
Perez, Guillaume. "Stratégies de médecine "régénérative" pour la réparation de la peau dans un modèle murin de brûlure profonde." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30096/document.
Повний текст джерелаScarring and regeneration are both repair processes observed in the animal kingdom, even though mammals always heal by a scar tissue formation that never restitute the initial tissue structure and properties. Burns healing can become abnormal and may subsequently affect the person's daily life. Considering pathological healings, we developed innovative regenerative medicine strategies to reduce or redirect the wound healing process towards a better issue in a mouse model of skin burn. First, we performed a cell therapy based on the administration of adipose mesenchymal stromal cells. Although the experiments showed promising immunomodulatory abilities, such cells failed to provide convincing results in our model of excessive burn healing. The second intent was designed after findings from the first approach and knowledge from regenerative models. Deep skin burns were treated by cold atmospheric plasma. We found that plasma-treated lesions were repaired by a considerably diminished scar. Experiments showed that the plasma treatment resulted in almost inexistent fibrosis through a reduction of inflammation and matrix deposition, emergence of regeneration follicles regeneration and a better restitution of hypodermis. In conclusion, cold atmospheric plasma significantly improves healing when applied on skin burns
Delaux, Joakim. "Activation de biopolymères par plasma atmosphérique non thermique." Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2310.
Повний текст джерелаFrançois Jerome's team developed new processes for the pretreatment of lignocellulosic biomass. This fundamental work is based on the use of non-thermal atmospheric plasma for the deplolymerization of biopolymers (cellulose, inuline) selectively. The advantage of this physical pretreatment is the non-using of catalysis or solvent and so it's resolve the dilution problem or the purifying problem usually met. A low consummation of energy can be cited too. This pretreatment could be increase the reactivity of biopolymers (hydrolysis for example) and get a better yield than the chemical or enzymes processes.The goal of the thesis is to understand what are the good conditions to obtain a cellulose more reactive for the chemical reactions and what the mechanism for the plasma treatment are. What kind of species react with the surface of the polymers and how they enter in the bulk ? What is the role of the nature and constitution (crystallinity, different polymer, kind of link…) ? Then, a study on the reactivity of the plasma cellulose was performed and the focus was put on the yield of glucose after acid hydrolysis. Like this, we can see the influence of the physical pretreatment (plasma, milling or both) on the cellulose. At the end, a mechanism is proposed by using all the information recovered in particularly with the structural analysis
Lecoq, Elodie. "Traitement préventif antifongique du pin maritime par post-décharge DBD à la pression atmosphérique et étude de l'action directe des post-déchargess sur les champignons de bleuissement du bois." Phd thesis, Université de Pau et des Pays de l'Adour, 2009. http://tel.archives-ouvertes.fr/tel-00465403.
Повний текст джерелаTyl, Clémence. "Study of the memory effect in atmospheric pressure townsend discharges in nitrogen with addition of oxidizing gas : temporally and spatially resolved electrical and optical characterizations." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30296.
Повний текст джерелаPlasma processes at atmospheric pressure using Dielectric Barrier Discharges (DBD) are a good alternative to low pressure non-thermal plasma processes for various applications such as surface treatment, thin-film coating, sterilization etc. Indeed, they can be operated without complex vacuum facilities and allow the treatment of large surfaces that can be implemented directly into assembly lines. However, DBDs are usually filamentary, leading to non-homogeneous depositions on the treated surfaces. In certain condition depending on the experimental parameters (geometry, gas nature, power supply, etc.), a homogeneous discharge can be obtained leading to a uniform surface treatment. Nevertheless, even in the homogeneous mode, the DBDs properties are not necessarily the same at any point on the discharge surface, because of the gas flow circulation in particular, but also in case of materials with a properties gradient, or in case of self-organization phenomena. In order to better characterize the spatial distribution of the discharge, a new local electrical diagnostic tool to measure the local current densities has been developed during this thesis. Indeed, electrical measurements are widely used to characterize the DBDs as they give access to various parameters such as the gas voltage, discharge current, dissipated power etc. However, the measured current is integrated on all the surface of the electrodes. To be able to measure the local currents, the 3×3 cm2 ground electrode from the discharge cell has been divided into 64 segments, and a data acquisition system has been developed in order to simultaneously acquire the 64 measured currents with a high enough sampling rate for the data processing. This new electrical diagnostic tool can be correlated in time and space with optical measurements with an intensified iCCD camera, coupled with optical filters, to obtain information on the densities of some species in the plasma. The aim of this thesis is to better understand to local power dissipation, and to refine the characterization of the involved species in the different discharge regimes, especially to obtain a homogeneous regime. Homogeneous DBDs are ignited by a Townsend breakdown. For a Townsend breakdown to occur, a production source of seed electrons is necessary between two discharges, when the electric field is lower than the breakdown voltage. This breakdown is related to a memory effect from one discharge to the following one, that is visible on the electrical measurements with a discharge current jump. The hypotheses on the memory effect origin can be separated into two categories.[...]
Douat, Claire. "Etude d’un micro-jet de plasma à pression atmosphérique." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112028/document.
Повний текст джерелаMicro plasma jets operating at atmospheric pressure in free atmosphere have recently attracted great attention because of their numerous advantages. In fact, micro plasma jets can be operated stably at atmospheric pressure and propagated over some centimeters in a free atmosphere. Moreover, these jets are non-thermal plasmas and create numerous reactive species. These properties allow to use this kind of plasma in many applications, such as surface treatment, decontamination, and plasma medicine.In this work it is shown that these micro plasma jets correspond to the fast propagation of an ionization front with no displacement of matter. A characterization of the plasma proprieties (e.g. distance and velocity of propagation) has been done as a function of the applied voltage, gas flow, gas composition and discharge geometry. The spatiotemporal distribution of the reactive species created by the plasma has been measured, with a special focus on the helium metastable atoms which have been measured by absorption laser spectroscopy. The helium metastable atom densities obtained are in the range of 1.10¹² to 5.10¹³ cm-³. Thanks to a very good spatiotemporal resolution, we have done a time-resolved full cartography of the plasma. This allowed us to show that the helium metastable atom distribution is annular near the nozzle and becomes circular as the plasma propagates. The maximum helium metastable atoms density has been measured at about half of the distance where the helium metastable atoms are present. This observation is in contradiction with results reported by numerical models. To gain further insight into the physical processes of the plasma, we have placed two micro plasma jets face to face. This study showed that both plasmas interact in such a way that they never come into contact, letting a space free of plasma between them. Moreover, we revealed that after the extinction of the plasmas, a second discharge is ignited in the previously free space. Fast imaging, spectroscopy diagnostics and electrical measurements showed that this second discharge is due to a polarity reversal, which creates an electron trap. Aiming the study of the application of micro plasma jets in the plasma medicine field, we have studied the degradation of plasmid DNA by our plasma jet. We observed that the plasma treatment leads mostly to single and double strands breaks, and to very little base oxidation and abasite site, even when oxygen is added into the gas mixture
Foletto, Marc. "Les micro-jets de plasma à pression atmosphérique et température ambiante." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30026/document.
Повний текст джерелаMicroplasma jets propagating in a helium flow surrounded by air at ambient pressure and temperature have attracted the attention of many researchers over the past decade. These microplasma jets are ignited in a cylindrical dielectric barrier discharge (DBD) powered by impulse or sinusoidal voltage pulses with an amplitude of several kilovolts and then propagate as an ionization wave in the helium flow outside the DBD. The plasma so-generated is confined to the region where helium is the dominant species because ionization of the surrounding air requires a significantly higher electric field strength than is present at the ionization front in the plasma jet. The putative biomedical applications of microplasma jets are particularly promising because they provide a way of producing reactive oxygen and nitrogen species some centimeters downstream from the DBD without significant gas heating. The objective of the work reported in this thesis has been to develop a better understanding of the influence of the operating conditions and geometry on the properties of the plasma jets. To this end, experimental and numerical studies of the hydrodynamics of the helium flow and simulations of the generation and propagation of the microplasma jet have been carried out
Jomaa, Neil. "Modélisations multi-physiques avec validations expérimentales des jets de plasmas froids d'hélium à la pression atmosphérique." Toulouse 3, 2014. http://www.theses.fr/2014TOU30094.
Повний текст джерелаThe development of reliable plasma sources well suited for biomedical applications is nowadays an increased need. These sources must meet strict requirements such as low temperature (quasi-ambient), easy handling, production of tuned active species, etc. The cold atmospheric pressure plasma jet generated by dielectric barrier discharge can meet these requirements. They are the focus of our hydro-electrodynamics model that is correlated with measurements for experimental validations. The modeled system implemented within our team consists of a quartz tube of small diameter crossed by helium gas flow and around which are wrapped two aluminum electrodes powered by a mono-polar pulsed voltage. Rapid imagery showed that the plasma jet that looks like continuous at naked eye is in reality a rapid succession of "plasma bullets" which are guided ionization waves propagating in He-air mixture, a hypothesis whose confirmation is one of the main objectives of the present work. The study was conducted in 2Drz. The finite element method was used for numerical discretization and COMSOL software is used. We developed three coupled models: hydrodynamic, electrostatic and electrodynamics models. Hydrodynamic modeling has provided us, for different radii of the tube and flow rates, the 2Drz distribution of the mole fraction of helium which is gradually diluted in the ambient air. This gas mixture is the medium in which the ionization waves propagate. The initial wave front in the vicinity of the outlet tube is the geometric electric field. Electrostatic simulation allowed us to quantify the influence of each parameter of the device on the maximum value of this geometric electric field. An important result of this study is an optimal configuration of the plasma jet device (experimentally validated) allowing us to maximize the length of the jet in order to facilitate the manipulation of the plasma source, or to minimize the magnitude of the voltage applied to the device to significantly reduce the energy cost in the case of a fixed length of the jet. The electro-hydrodynamic simulation of the plasma jet is based on the coupled system formed by the Poisson equation, the equations of particle transport, the electron energy conservation equation, the convecto-diffusive transport equation of helium in ambient air and the Navier-Stokes equation. The required input data in the models as reactions and transport coefficients determined from multi-term Boltzmann equation solution take into account the progressive dilution of He in the air. Each case of simulation of our 2Drz multi-physics model is time consuming calculation (a few days on a Xeon processor) but provide us a lot of valuable information for the optimization of the jet. Some of them are confirmation of "guided streamer " nature of plasma jet, the 2Drz rigorous analysis correlated to reaction kinetics of the different phases of the jet (development, propagation and post-discharge), the determination of its length and velocity profile, the identification of mechanisms leading to its annular shape experimentally observed, the spatial and temporal study of the average electron energy, the local electric field generating the second ionization wave, the electron current and density of the charged and neutral species such as the helium metastable playing a major role in the chemistry of the plasma and atomic oxygen because of its importance in biomedical applications. Good consistencies observed between our results and the experimental measurements are elements of validation of our hydro-electrodynamics model. We also conducted a systematic parametric study to quantify the effect of the voltage and the tube inner radius on the characteristics of the plasma jet. We have finally given, in an annex, our contribution on the physics of the interactions between our jet and micro-organisms
Orrière, Thomas. "Confinement micrométrique des décharges pulsées nanosecondes dans l'air à pression atmosphérique et effets électro-aérodynamiques." Thesis, Poitiers, 2018. http://www.theses.fr/2018POIT2272/document.
Повний текст джерелаNon-thermal plasmas generated in air at atmospheric pressure have numerous potential applications due to their non-equilibrium chemistry and ease of use. Their main advantages lie in the cost-efficient production of reactive and charged species compared to that of equilibrium chemistry. The aim of this thesis is to combine nanosecond repetitively pulsed discharges (NRP) with a microscale geometry. Using this combination, we seek to reduce the excessive heat release of NRP sparks, while nonetheless reaching high densities of reactive species and electrons. This work is comprised of three main parts. Our first goal is to study the breakdown phase, in which energy is deposited and charged species are produced. We employ both electrical characterization and optical emission spectroscopy in order to show that the NRP microplasma fully ionizes and dissociates the gas. The second part consists of the study of the recombination phase, in which the produced species recombine or survive. Results show that three-body recombination can explain the electron lifetime in this phase. Finally, we study the transport of plasma chemical species from the microplasma to a DC-biased conductive plate representing a substrate. By applying a voltage to this third electrode, we drive an electro-thermal plume via an ionic wind from the microplasma to the plate. This flow is investigated mainly by particle image velocimetry as well as Schlieren imaging. This work shows the capability of NRP microplasmas to produce high densities of reactive and charged species and transport them to a surface using an electrohydrodynamic plume
Delair, Laurent. "Caractérisation de sources plasmas dédiées à la simulation de rentrées atmosphériques et au traitement de polluants : arc soufflé basse pression et décharge de polluants." Rouen, 2004. http://www.theses.fr/2004ROUES052.
Повний текст джерелаThis work deals with the experimental study of two plasma sources : an original plasma torch (two anodic arc roots) which generates a low pressure nitrogen arcjet, and an atmospheric pressure gliding arc. The thermodynamic characteristics of the nitrogen plasma – densities and temperatures – are deduced from emission spectroscopy analysis, from its creation zone to its expansion zone. Mach number measurements are carried out at the torch exit. The study of the arc(s dynamic behaviour highlights an acoustic resonance frequency inside the arc chamber. The analysis of the gliding arc with emission spectroscopy reveals its non-equilibrium state and some abnormal ionic line broadenings in its creation zone due to plasma turbulence phenomena. Simultaneous high speed acquisitions of electrical signals and light intensity confirm its classical dynamical behaviour : ignition, lengthening, extinction. They also show the impulse behaviour of the arc column as it moves between the electrodes
Magnier, Pierre. "Etude expérimentale du contrôle d'écoulements aérodynamiques subsoniques par action de plasmas froids surfaciques à pression atmosphérique." Phd thesis, Université d'Orléans, 2007. http://tel.archives-ouvertes.fr/tel-00264817.
Повний текст джерелаAbahazem, Alyen. "Etudes expérimentales des décharges couronne pour la dépollution des gaz." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/716/.
Повний текст джерелаThe aim of this work is to study the electrical and optical characteristics of corona discharges in order to better understand their properties as a function of various operating parameters and to have the elements of experimental validation of models used to optimize these sources of active species for environmental applications. This work consists to make an experimental study of corona discharge in positive polarity, in point-to-plane geometry in air and nitrogen at atmospheric pressure, in both cases DC and pulsed voltage. The electrical analysis of corona discharge is carried out as a function of several parameters (inter-electrode distance, applied voltage, frequency and pulse width of voltage) in air and then in nitrogen. The morphology analysis of the discharge was conducted by ICCD camera. The emission spectra in the visible range were analyzed for DC and pulsed voltages in the case of air and then for the pulsed voltage in the case of the nitrogen. A comparative analyses between the electrical characteristics were made between DC and pulsed voltages in air and then between air and nitrogen corona discharges for pulsed voltage. The differences between the emission spectra of air and nitrogen have been analyzed with an emphasis on the presence of NOgamma emissions only in the case of the nitrogen and their absence in the case of air is due to the quenching of NOgamma by oxygen molecules. A new laboratory reactor multi points-plane has been implemented. Electrical and imagery analyses were performed by varying the number of points, the inter-electrode distance and the applied voltage
Maechler, Louison. "Dépôts de films organosiliciés réalisés par décharge à barrière diélectrique homogène à la pression atmosphérique : application aux films multicouches." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1070/.
Повний текст джерелаThe aim of this work is to better understand deposition processes of thin films using an atmospheric pressure cold plasma, through the synthesis of organic and inorganic materials. Two discharges are used: the Atmospheric Pressure Townsend Discharge (APTD) in nitrogen and the Atmospheric Pressure Glow Discharge (APTD) in helium. In both cases, the precursor used is hexamethyldisiloxane (HMDSO) and the oxidizing gas is nitrous oxide (N2O). The approach consists in firstly determining the chemical and structural properties of films obtained with or without oxidant gas. After this step, a discussion is proposed on the gas-phase reaction mechanisms that may explain the obtained deposits. Finally, this work highlights some possible applications of these deposits obtained at atmospheric pressure through the realization of gas barrier multilayers and of rigid multilayers with antifog properties
Gazeli, Kristaq. "Étude expérimentale de micro-plasmas froids à la pression atmosphérique générés par des hautes tensions de formes différentes." Thesis, Pau, 2015. http://www.theses.fr/2015PAUU3019/document.
Повний текст джерелаThe present PhD thesis is devoted to the study of atmospheric pressure cold micro-plasmas produced in different Dielectric Barrier Discharge (DBD) reactors which are driven by pulsed or sinusoidal high voltages. Noble gases such as helium and argon are used as carrier gases, whereas admixtures with nitrogen and oxygen are studied as well. The formation of Reactive Nitrogen and Oxygen Species (RNS, ROS) is thus achieved, and the possibility of improving the chemical (re)activity of the plasmas is demonstrated. This is of interest in the treatment of inert or living materials (e.g. surface functionalization, cell inactivation, living tissue regeneration, etc.). Plasmas are characterized by recording electrical and optical features as a function of principal operational parameters, including voltage amplitude and frequency, gas flow rate, electrode configuration, and voltage duty cycle in the case of pulsed waveform. The physico-chemical (re)activity of the plasmas is thus evaluated, while at the same time mechanisms on the plasma generation and paths for chemistry optimization are unveiled. Finally, the efficiency of the plasma in relation to biomedical applications is tested by treating different biological systems (bacteria, liposomes, cells) while preventing any thermal effect
Girard, Fanny. "Analyse physico-chimique de milieux liquides d’intérêt biologique exposés à des plasmas froids produits à pression atmosphérique et température ambiante." Thesis, Pau, 2017. http://www.theses.fr/2017PAUU3025/document.
Повний текст джерелаCold plasmas are partially ionized gases, very rich in a physico-chemical point of view. This property characterizes cold plasmas today generated at atmospheric pressure and ambient temperature and was used since about fifteen years approximately for biomedical applications (haematology, dermatology, cancer research, odontology etc.). The efficiency of these cold plasmas in the field of the medicine was proved by numerous studies. However, the involved biological phenomena are not still well included, and it is essential to know what could be the possible unwanted side effects of these reactive ionized gases. The first level of interaction of plasmas with living matter is the one with the liquid phase, which is present on the tissue surface, in vivo cells or in culture. For a decade, a particular attention was thus worn in the interactions of plasmas with liquids, to bring a level of additional understanding. The understanding of these interactions constituted the axis of this work. Various cold plasmas reactors (generated at atmospheric pressure and ambient temperature) were developed, in order to control the interactions of these plasmas with the ambient air which can be problematic for the aimed applications. The nature of the gas used to initiate the plasma was modified, to know its influence on the chemical reactivity of the gas phase. For that purpose, measurements of optical emissive spectroscopy (OES) were necessary. Besides, new electrochemical sensors and methodological approaches were developed in order to identify and quantify the reactive nitrogen and oxygen (RONS) produced in physiological liquid media, exposed to these ionized gases. The electrochemical analyses were combined UV-visible absorption spectroscopy as well as other methods of chemistry (pH-metry/conductimetry). One of the aimed objectives is to establish a correlation between the reactive species generated in the gas phase and in the liquid phase. Finally, experiments allowed us to analyze the production of RONS in liquids in situ and in real time. OES measurements showed that there are numerous chemical species generated in various plasmas (NO°, HO°, O, N2+ (FNS) etc.). The analyses of the liquid phase revealed the presence of stable oxygen and nitrogen species (H2O2, NO2-, NO3-), directly correlated with the species detected in plasmas. Furthermore, the diverse methodologies of chemical analysis allowed the detection and quantification of RONS such as the peroxynitrite anion ONOO-. The obtained results should allow to arrest in a finer way the effects led by various cold plasmas in physiological liquid media to establish links with the studies led on cultured cells and on skin within the framework of a research program financed by the ANR, National Agency of the Research
Quinio, Géraldine. "Modélisation numérique de la génération d’un plasma d’air dans un écoulement aérodynamique." Toulouse, INSA, 2005. http://eprint.insa-toulouse.fr/archive/00000445/.
Повний текст джерелаOrder to reduce the flash points in air intake of aircraft, a considered deviee consists in the partial ionisation of the air around the air intake. The aim of the thesis is to develop mathematical and numerical models in order to apprehend the main physical mechanisms which occur in the generation of air plasmas at atmospheric pressure in air flows. An asymptotic analysis of simple ionization kinetics of air flows at atmospheric pressure is first proposed. The existence of the plasma depends on the value of the flow velocity relative to a threshold value and on the existence of metastables which detach electrons from negative ions. Secondly, we were interested in the modelling of capillary discharges which allows the genera tion of a homogeneo us discharge in air at atmospheric pressure. A OD model has been made in order to understand the main physical mechanisms occurring in the discharge initiation. The numerical simulations shows the wall phenomena take an important place in the operation of the discharge. Lastly, a 2D model is developed to model a negative tip/plane corona discharge in air flows. The mode! consists of a system of non-linear convection/diffusion /reaction equations coupled with the Poisson equation. The current induced by the plasma circulation in the extemal circuit is Iinked with the potential through an ordinary differential equation in time. The numerical simulations show that when the flow velocity becomes important, a periodical formation of plasma channels carrying away by the air flow is observed
Profili, Jacopo. "Dépôt de couches minces nanocomposites par nébulisation d'une suspension colloïdale dans une décharge de Townsend à la pression atmosphérique." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30131/document.
Повний текст джерелаThis PhD work is focused on the development of a new generation of nanocomposite thin films using cold plasma at atmospheric pressure. The main objective is to improve the understanding of the mechanisms involved in this process.The strategy is based on the injection of a metal oxide nanoparticles suspension in a dielectric barrier discharge operating in nitrogen (Townsend discharge). At first, the nanocomposite thin film is deposited sequentially: the fabrication of the inorganic matrix of silica (SiO2) is separated from the collection of the nanoparticles (TiO2). Then, the nanocomposite layers are obtained by a one-step process using a direct injection inside the discharge of nanoparticles dispersed in a polymerizable organosilicon precursor (HMDSO). This manuscript is divided into four major parts: first, the synthesis of the nanoparticles and the study of their dispersion in different solvents are presented. Then, in the second part we focus on the atomization of the colloidal suspension, on the analysis of the size distributions of the injected objects and on the study of their transport towards the discharge area. These results are then used to assess the influence of the discharge on the transport and the quality of deposited nanocomposite thin films. Finally, the thin films properties are investigated when depositing on wood substrates
Lecoq, Elodie. "Traitement préventif antifongique du pin maritime par post-décharge DBD à la pression atmosphérique et étude de l'action directe des post-décharges sur les champignons de bleuissement du bois." Pau, 2009. http://www.theses.fr/2009PAUU3034.
Повний текст джерелаThe aim of this work was to study the potentialities of cold plasma treatments for preventive and curative fungicidal applications on Pinus Pinaster. Treatments were realized by exposing samples to afterglows, generated in Dielectric Barrier Discharge (DBD) reactors. For preventive application, the aim is to define if DBD afterglow treatment could be used to avoid leachability of fungicidal products used in wood industry. A fungicidal molecule containing a reactive group and a quaternary ammonium was synthesized. It can be fixed on wood by a covalent bond and its leaching can that way be avoided. It was shown that an afterglow treatment could improve the kinetics of grafting reaction in comparison with treatment by heating. An afterglow assisted fixation of this molecule on wood can consequently protect it durably against blue-stain fungi attacks. For Curative application, direct effect of afterglows on fungi spores was studied. It was shown that afterglow exposure of Aureabasidium pullulans, Ceratocystis Sp. , Penicillium Sp. And Gliocladium Sp. Spores could lead to a quasi-total inhibition of their growth, even for less than 10 minutes treatment duration. Consequently, this PhD work has shown that DBD afterglow treatments could provide solutions in wood industry, for fungicidal preventive and curative applications
Olivier, Sébastien. "Réalisation d'un dépôt photocatalytique de dioxyde de titane à basse température avec une torche plasma à la pression atmosphérique." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0007/document.
Повний текст джерелаThis PhD work deals with the deposition of photocatalytic thin films of titanium dioxide at low temperature in the post-discharge of an atmospheric pressure plasma process. The main objective is the development of a low cost route for the deposition of self-cleaning coatings on 3D thermosensitive substrates. The deposited coatings present good photocatalytic properties which origin is firstly investigated. The elemental composition, the growth mechanisms and the crystallinity of three series of coatings corresponding to three different deposition temperatures are studied. The high specific surface of the coatings, due to the growth of agglomerates, appears to be the main parameter responsible for such photocatalytic properties. But these agglomerates are also responsible for the poor mechanical properties of the coatings as their adhesion decreases with their size. These agglomerates are formed in gas phase in recirculation loops and develop through multiple phenomena: CVD growth, agglomeration at the surface of the coating and redeposition due to the influence of the post-discharge on the surface of the coating. Moreover, at a given precursor flow rate, their number and their size are interlocked. Thus, with the aim of optimizing the deposition process, the control of the formation of such structures through the decrease of the precursor flow rate, the power input and the gas flows are mandatory and are a perspective of this PhD work
Chicheportiche, Alexandre. "Données de base des ions atomiques et moléculaires de l'hélium et de l'argon pour l'optimisation des jets de plasmas froids utilisés dans le domaine biomédical." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2437/.
Повний текст джерелаThe use of cold plasma jets at atmospheric pressure (AP) for biomedical applications is a hot research topic. Such devices produce many active species (photons, radicals, charged particles, electric field, etc. ) very useful for biomedical applications. The challenge for the plasma physics community is to tune such plasma devices to abundantly or selectively produce actives species beforehand identified for their biological effects. To reach this goal, physicochemical models have been developed but require, in input data, the transport coefficients (not always available in the literature) of ions affecting the kinetics of the plasma jet. In this thesis work we are interested in helium or argon plasma jets. Thus, transport coefficients of He+ and He2+ ions as Ar+ and Ar2+ ions have been calculated in their parent gas. The originality of the work concerns the molecular ions (He2+ and Ar2+) which play the main role in the plasma jet dynamics since they are overwhelmingly present at the AP. The transport coefficients are closely related to the collision cross sections and then to the ion-neutral interaction potential curves. For the He+/He interaction system, a 1D quantum method without approximation has been used for the collision cross section calculation and an optimized Monte Carlo code allowed us to obtained the transport coefficients in the experimental error bars. On the other side, for the molecular ions He2+, two calculation methods have been considered: a 1D quantum method and a hybrid method mixing classical and quantum formulations. A compromise between these two methods finally allowed us to obtain reduced mobilities with a mean relative deviation from experiments of 5% and to expand the latter to higher electric fields. Diffusion coefficients and reaction rates, not available in the literature, have been also calculated. For the argon plasma jet, the transport coefficients for atomic ions in the ground 2P3/2 state and metastable 2P1/2 state have been obtained, using quantum collision cross sections, up to 1500 Td (1 Td = 10-17 V. Cm²) with a mean relative deviation from measurements below 0. 2%. Finally, for Ar2+ ions, the hybrid method allowed us to obtain reduced mobilities with a mean relative deviation of 2% from experiments and to calculate the diffusion coefficients and reaction rates not available in the literature
Hamidi, Assia. "Développement d’un chargeur à décharge couronne pour la mesure à 10 Hz de la concentration d’un aérosol atmosphérique." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112399.
Повний текст джерелаThe goal is to develop an aerosol charger based on a corona discharge for atmospheric concentration measurements (10^3-10^5 cm^-3) within a response time of 100 ms.Two ion sources, point-To-Hole and wire-To-Slit have been characterized. The increase of the ion flow in the post-Discharge by EHD ion confinement in both the discharge gap and the hole has been shown.At first, using an experimental survey driven in two mixing configurations, concentric and face-To-Face, we have confirmed the aerosol diffusion charging law which depends on aerosol diameter and Ni.t product, with Ni, the ions concentration and t, the charging time. Thus, the originality of this charger relies on the very high heterogeneity of unipolar ion densities (Ni0 >10^9 cm^-3) required to compensate the charging time of 50 ms. In these conditions, we have shown that aerosol diameter and the charging dynamic (which depends also on the diameter) control the aerosol trajectory.The chargers have, next, been compared in different operating conditions, mainly in terms of the maximal charging and the minimal losses. In the chosen charger (point-To-Hole ion source and concentric mixing), the relations charge/mobility and losses according to diameter have been characterized. We have also shown the linearity of the charged particles current with the aerosol concentration which allows the current-Concentration data inversionThe preliminary measurement system composed by the charger, the separator and the particle current measurements, satisfies the objectives of the study in terms of the concentration detection limit (10^3 cm^-3) and the response time (100 ms). We have thus shown the feasibility of an atmospheric aerosol concentration measurement system at 10 Hz using a corona discharge charger provided that the separation power is improved. Furthermore, knowing that aerosol losses are negligible and the lower limit of the partial charging, the developed charger is adaptable with other applications
Faider, Wilfrid. "Traitement de l’acétaldéhyde par décharges électriques impulsionnelles dans les mélanges de gaz atmosphériques : cinétique et efficacité énergétique." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112023/document.
Повний текст джерелаThe present study deals with the kinetics analysis of acetaldehyde (CH₃CHO) conversion in electrical discharges with different spatial qualities et at room temperature. Acetaldehyde concentrations up to 5000 ppm in nitrogen-based gas mixture containing up to 20% of oxygen have been investigated. Three different plasma reactors were used: an UV510 reactor producing a homogeneous plasma thanks to a pre-ionization by UV radiation (photo-triggered), a plane-to-plane and a rod-tube dielectric barrier discharges (DBDs) reactors, In both DBDs reactors discharges were driven by high voltage pulses allowing the production of weakly inhomogeneous plasma in the plane geometry and highly filamentary discharges in the cylindrical one. A high speed imaging diagnostic (ns range) of the plane-to-plane DBD shows that the plasma can be considered quasi-homogeneous. Based on a self-consistent 0D model, the kinetics study of the N₂/CH₃CHO mixture conversion in the photo-triggered discharge shows the importance of nitrogen molecule metastable states , i.e. the triplet A³Σu⁺ and the singlets group a' ¹∑⁻u, a ¹∏g, et w ¹Δu, in the acetaldehyde dissociation process. A minimum coefficient of 6.5×10⁻¹¹ cm³.s⁻¹ has been estimated for the quenching of N₂ singlets state by acetaldehyde. For the triplet states quenching the coefficient of has been evaluated between 4.2×10⁻¹¹ cm³.s⁻¹ and 6.5×10⁻¹¹ cm³.s⁻¹. This dissociation process produces radicals as CH₃, CH₃CO, HCO, H, O, and molecules like CH₄, CH₂CO, C₂H₄, C₂H₂, H₂, CO. Thus, the major by-products detected at the end of the post-discharge time are methane, hydrogen, carbon monoxide and ethane; smaller amounts of acetylene, ethene, acetone and acetonitrile were also detected. In containing oxygen mixtures, the importance of the CH3CHO dissociation processes due to N₂ metastable states quenching of decreases in favor of oxidation processes promoted by the hydroxyl radical, OH, and atomic oxygen, O (³P). Time-resolved measurements of the OH radical in the photo-triggered post-discharge show a very high reactivity of this radical with the by-products of acetaldehyde conversion. A maximum density of OH radical equal to 3.5×10¹⁴ cm⁻³ was measured for 10% oxygen and 5000 ppm of acetaldehyde. The kinetic scheme adopted in the self-consistent model for the same gas mixture gives a higher density value; by the way the model is in good agreement with the acetaldehyde conversion in N₂/O₂/CH₃CHO mixtures, as well as with the methane and ethane produced concentrations. Finally, the comparison of the three studied reactors energy efficiency shows that, for low oxygen content (less than 2%), the homogeneity of the discharge promotes the acetaldehyde conversion
Levasseur, Olivier. "Étude de la dynamique de croissance de revêtements nanostructurés multifonctionnels sur le bois par plasmas froids à la pression atmosphérique." Thèse, 2016. http://hdl.handle.net/1866/18481.
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