Thèses sur le sujet « Particles in cell (PIC) »
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Pierru, Julien. « Development of a Parallel Electrostatic PIC Code for Modeling Electric Propulsion ». Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34597.
Texte intégralMaster of Science
Spicer, Randy Lee. « Validation of the DRACO Particle-in-Cell Code using Busek 200W Hall Thruster Experimental Data ». Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/34460.
Texte intégralThe DRACO code has been recently modified to improve simulation results, functionality and performance. A particle source has been added that uses the Hall Thruster device code HPHall as input for a source to model Hall Thrusters. The code is now also capable of using a non-uniform mesh that uses any combination of uniform, linear and exponential stretching schemes in any of the three directions. A stretched mesh can be used to refine simulation results in certain areas, such as the exit of a thruster, or improve performance by reducing the number of cells in a mesh. Finally, DRACO now has the capability of using a DSMC collision scheme as well as performing recombination collisions.
A sensitivity analysis of the newly upgraded DRACO code was performed to test the new functionalities of the code as well as validate the code using experimental data gathered at AFRL using a Busek 200 W Hall Thruster. A simulation was created that attempts to numerically recreate the AFRL experiment and the validation is performed by comparing the plasma potential, polytropic temperature, ion number density of the thruster plume as well as Faraday and ExB probe results. The study compares the newly developed HPHall source with older source models and also compares the variations of the HPHall source. The field solver and collision model used are also compared to determine how to achieve the best results using the DRACO code. Finally, both uniform and non-uniform meshes are tested to determine if a non-uniform mesh can be properly implemented to improve simulation results and performance.
The results from the validation and sensitivity study show that the DRACO code can be used to recreate a vacuum chamber simulation using a Hall Thruster. The best results occur when the newly developed HPHall source is used with a MCC collision scheme using a projected background neutral density and CEX collision tracking. A stretched mesh was tested and proved results that are as accurate as a uniform mesh, if not more accurate in locations of high mesh refinement.
Master of Science
Godar, Trenton J. « Testing of Two Novel Semi-Implicit Particle-In-Cell Techniques ». Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1402492857.
Texte intégralZahri, Abdellatif. « Développement du modèle PIC-MCC 2D : application aux décharges radiofréquence ». Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1344/.
Texte intégralThe particle-in-cell method combined with the Monte Carlo techniques is a well established method for plasma modelling, and is widely used to simulate low pressure radiofrequency discharges. This technique is a simple and effective method for solving a wide variety of complex problems involving a large number of particles moving under the action of internal forces and external forces (electromagnetic fields. . . ) The purpose of our model is to understand and characterize the behaviour of low pressure plasmas in a two-dimensional geometry. We want to understand what is happening in the sheath and in particular the behaviour of the ions. In this work, we describe the PIC-MCC models and techniques needed to build such models. We chose this technique by its ability to describe correctly the plasma physics at low pressure. Indeed, this technique provides more details without any assumption on the distribution function of electrons or ions, which is far from being the case for other models including fluid models. We show some distribution functions (density and energy of charged particles, EEDF) ; the electrical characteristics of the discharge are presented. This work is part of the European project EMDPA : New Elemental and Molecular Depth Analysis of advanced materials by modulated radio frequency glow discharge time of flight mass spectrometry. This project is funded by the European Commission through the research program for technological development
Horken, Kempton M. « Isolation of photosynthetic membranes and submembranous particles from the cyanobacterium synechococcus PCC 7942 ». Virtual Press, 1996. http://liblink.bsu.edu/uhtbin/catkey/1036184.
Texte intégralDepartment of Biology
Hammel, Jeffrey Robert. « Development of an unstructured 3-D direct simulation Monte Carlo/particle-in-cell code and the simulation of microthruster flows ». Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-0510102-153614.
Texte intégralBarsamian, Yann. « Pic-Vert : une implémentation de la méthode particulaire pour architectures multi-coeurs ». Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAD039/document.
Texte intégralIn this thesis, we are interested in solving the Vlasov–Poisson system of equations (useful in the domain of plasma physics, for example within the ITER project), thanks to classical Particle-in-Cell (PIC) and semi-Lagrangian methods. The main contribution of our thesis is an efficient implementation of the PIC method on multi-core architectures, written in C, called Pic-Vert. Our implementation (a) achieves close-to-minimal number of memory transfers with the main memory, (b) exploits SIMD instructions for numerical computations, and (c) exhibits a high degree of shared memory parallelism. To put our work in perspective with respect to the state-of-the-art, we propose a metric to compare the efficiency of different PIC implementations when using different multi-core architectures. Our implementation is 3 times faster than other recent implementations on the same architecture (Intel Haswell)
Doche, Antoine. « Particle acceleration with beam driven wakefield ». Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX023/document.
Texte intégralPlasma wakefield accelerators (PWFA) or laser wakefield accelerators (LWFA) are new technologies of particle accelerators that are particularly promising, as they can provide accelerating fields of hundreds of Gigaelectronvolts per meter while conventional facilities are limited to hundreds of Megaelectronvolts per meter. In the Plasma Wakefield Acceleration scheme (PWFA) and the Laser Wakefield Acceleration scheme (LWFA), a bunch of particles or a laser pulse propagates in a gas, creating an accelerating structure in its wake: an electron density wake associated to electromagnetic fields in the plasma. The main achievement of this thesis is the very first demonstration and experimental study in 2016 of the Plasma Wakefield Acceleration of a distinct positron bunch. In the scheme considered in the experiment, a lithium plasma was created in an oven, and a plasma density wave was excited inside it by a first bunch of positrons (the drive bunch) while the energy deposited in the plasma was extracted by a second bunch (the trailing bunch). An accelerating field of 1.36 GeV/m was reached during the experiment, for a typical accelerated charge of 40 pC. In the present manuscript is also reported the feasibility of several regimes of acceleration, which opens promising prospects for plasma wakefield accelerator staging and future colliders. Furthermore, this thesis also reports the progresses made regarding a new scheme: the use of a LWFA-produced electron beam to drive plasma waves in a gas jet. In this second experimental study, an electron beam created by laser-plasma interaction is refocused by particle bunch-plasma interaction in a second gas jet. A study of the physical phenomena associated to this hybrid LWFA-PWFA platform is reported. Last, the hybrid LWFA-PWFA scheme is also promising in order to enhance the X-ray emission by the LWFA electron beam produced in the first stage of the platform. In the last chapter of this thesis is reported the first experimental realization of this last scheme, and its promising results are discussed
Drouin, Mathieu. « Vers la simulation particulaire réaliste de l'interaction laser-plasma surcritique : conception d'un schéma implicite avec amortissement ajustable et fonctions de forme d'ordre élevé ». Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2009. http://tel.archives-ouvertes.fr/tel-00442715.
Texte intégralYADAV, MONIKA. « SOME ASPECTS OF LASER-PLASMA INTERACTION FOR ELECTRON ACCELERATION ». Thesis, DELHI TECHNOLOGICAL UNIVERSITY, 2021. http://dspace.dtu.ac.in:8080/jspui/handle/repository/18736.
Texte intégralDrouin, Mathieu. « Vers la simulation particulaire réaliste de l'interaction laser-plasma surcritique : conception d'un schéma implicite avec amortissement ajustable et fonctions de forme d'ordre élevé ». Phd thesis, Cachan, Ecole normale supérieure, 2009. https://theses.hal.science/tel-00442715/fr/.
Texte intégralLaser-plasma interaction and electronic transport are pure kinetic processes thus requiring to solve the complete Vlasov-Maxwell system of equations. This thesis focuses on PIC (‘‘Particle-In-Cell'') methods, and is intended to widen the operating regime of such methods. First, we present the linear stability analysis of an explicit PIC algorithm including spatial and temporal step size effects. This study highlights the aliasing instability, which we link to the more intricate issue of numerical heating in PIC codes in the overcritical regime. We show the beneficial influence of using an increasingly high order weight function to drop this heating, thereby allowing to reach overcritical regimes relevant for comparison with experiments. Implicit PIC codes are not submitted to the constraints affecting their explicit counterparts. Particularly we can relax the need to solve high frequency electronic modes. Such a property is extremely valuable when we model the interaction between a high intensity laser and a highly overcritical plasma. Here, we give the relativistic extension of the direct implicit method, provided with an adjustable damping parameter and high order weight functions. This formalism was implemented in the code ELIXIRS, 2D in space and 3D in velocity. This code was validated for various plasma physics configurations, among them one or two electronic temperatures plasma expansions, high intensity laser-plasma interaction, and also beam-plasma instabilities in the relativistic regime. Especially, we prove the capability of the code to catch the main characteristics of the aforementioned phenomena, despite a crude spatio-temporal discretisation, thus providing significant gains of computation time
Nakata, Michael Takeshi. « Simulating the FTICR-MS Signal of a Decaying Beryllium-7 Ion Plasma in a 2D Electrostatic PIC Code ». Diss., CLICK HERE for online access, 2010. http://contentdm.lib.byu.edu/ETD/image/etd3370.pdf.
Texte intégralFerri, Julien. « Étude des rayonnements Bétatron et Compton dans l'accélération d'électrons par sillage laser ». Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX094/document.
Texte intégralAn ultra-short and ultra-intense laser pulse propagating in a low-density gas can accelerate in its wake a part of the electrons ionized from the gas to relativistic energies of a few hundreds of MeV over distances of a few millimeters only. During their acceleration, as a consequence of their transverse motion, these electrons emit strongly collimated X-rays in the forward direction, which are called betatron radiations. The characteristics of this source turn it into an interesting tool for high-resolution imagery.In this thesis, we explore three different axis to work on this source using simulations on the Particles-In-Cells codes CALDER and CALDER-Circ. We first study the creation of a betatron X-ray source with kilojoule and picosecond laser pulses, for which duration and energy are then much higher than usual in this domain. In spite of the unusual laser parameters, we show that X-ray sources can still be generated, furthermore in two different regimes.In a second study, the generally observed discrepancies between experiments and simulations are investigated. We show that the use of realistic laser profiles instead of Gaussian ones in the simulations strongly degrades the performances of the laser-plasma accelerator and of the betatron source. Additionally, this leads to a better qualitative and quantitative agreement with the experiment.Finally, with the aim of improving the X-ray emission, we explore several techniques based on the manipulation of the plasma density profile used for acceleration. We find that both the use of a transverse gradient and of a density step increases the amplitude of the electrons transverse motions, and then increases the radiated energy. Alternatively, we show that this goal can also be achieved through the transition from a laser wakefield regime to a plasma wakefield regime induced by an increase of the density. The laser wakefield optimizes the electron acceleration whereas the plasma wakefield favours the X-ray emission
Donderici, Burkay. « Time-Domain Solvers for Complex-Media Electrodynamics and Plasma Physics ». The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1216744283.
Texte intégralPenkal, Bryan James. « Steps in the Development of a Full Particle-in-Cell, Monte Carlo Simulation of the Plasma in the Discharge Chamber of an Ion Engine ». Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1367586856.
Texte intégralRevel, Adrien. « Modélisation des plasmas magnétisés. Application à l'injection de neutres pour ITER et au magnétron en régime impulsionnel haute puissance ». Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112083/document.
Texte intégralA plasma is defined as a partially or completely ionized gas. Even though, they are very present in the visible universe, natural plasmas are rare on Earth. However, they are a major interest for industries and research institutes (surface treatment, spatial propulsion). Nevertheless, the understanding of plasma behavior is complicated because of the numerous physical fields involved. Moreover, theses plasmas can be magnetized, i.e., a magnetic field, external or induced, affects significantly the particle trajectories: r/L<1 where r is the Larmor radius and L the typical length of the system. This thesis is focused on the plasma modeling in two device: the accelerator of the ITER's neutral beam injector (NBI) and the magnetron in DC or HiPIMS regime. The feasibility of nuclear fusion on Earth is subject of numerous research around the world. Because of the energy necessary to get over the Coulomb barrier, the plasma must be confined. For ITER, the confinement is achieved by intense magnetic fields. However, to reach the required conditions of nuclear fusion reactions, especially in temperature, a high energy (1MeV) neutral beam injector is needed. The particle acceleration is a critical part in the creation of the neutral beam and it represents a technical challenge which is studied in this thesis work. The magnetron is an industrial process for creating thin film by physical sputtering. The ions created by a plasma discharge tear the atoms out of the cathode which are then deposited on the anode. The magnetic field created by permanent magnets trap the electrons near the cathode improving the process efficiency. The plasma behavior inside the magnetron is studied in direct and pulsed current as well as the appearance of self-organized structures in rotation around the magnetron axis. To study these devices, several program of numerical simulation have been developed. The Particle-In-Cell methode has been chosen because it takes into account, self-consistently, the space charge of the particules. Several techniques (null collision technique, Monte Carlo Collision, a posteriori Monte Carlo) and improvement (Non uniform mesh, third order charge projection) have been developed and implemented. Moreover, an original method, Pseudo 3D, allowing a three dimensional study of the magnetron, has been used with success. Finally, these programs have been parallelized to reduce the computation time
Spirkin, Anton M. « A three-dimensional particle-in-cell methodology on unstructured Voronoi grids with applications to plasma microdevices ». Link to electronic dissertation, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-050506-145257/.
Texte intégralFaure, Nicolas. « Modélisation électromagnétique en présence de charges d’espace : application à l’étude de tubes électroniques de type magnétron ». Limoges, 2006. http://aurore.unilim.fr/theses/nxfile/default/c0847439-d574-4838-b1c8-f9b3ab431dbb/blobholder:0/2006LIMO0022.pdf.
Texte intégralThis work deals with electromagnetic modelisation in the presence of space charges. On the one hand, we developed a Particle-In-Cell code with an algorithm of the Finite Difference Time Domain type. After realisation and validation of a 2D PIC code on a rising sun structure, we extended then validated the code in 3D. In addition, we studied the inherent static and electromagnetic aspects in the electronics tubes of magnetron type operation. This approach allowed us best encircled influence of various elements like the straps and to emit at last certain rules to optimise the synthesis of new sources. This study makes it possible to have codes to optimise or develop new sources
Sprenkle, Robert Tucker. « Ion Friction at Small Values of the Coulomb Logarithm ». BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6979.
Texte intégralPebernet, Laura. « Etude d'un modèle Particle-In-Cell dans une approximation Galerkin discontinue pour les équations de Maxwell-Vlasov : recherche d'une solution hybride non conforme efficace ». Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1080/.
Texte intégralThis thesis presents the study and the development of an efficient numerical simulation's tool for the modeling of plasma/microwave interaction in an electromagnetic software based upon a Discontinuous Galerkin (DG) scheme. This work is organized following two main steps. First, we develop a Particle-In-Cell (PIC) model appropriate for DG scheme. For this, on the one hand, we propose a hyperbolic corrector method to take into account the charge conservation law and, on the other hand, we integrate physical plasma models such as high power microwave sources, emission particles surfaces and electrons beams. Then, we propose also optimal performances for the coupling of Maxwell-Vlasov equations in order to increase the efficiency and the size of the applications to treat. This leads to study a non conformal hybridization of methods to solve the Maxwell-Vlasov problem. In the first time, we work on a hybrid method between different numerical schemes to solve a 1D Maxwell problem on non conformal meshes. In the second time, we interest in a 2D TE Maxwell problem, in order to introduce a PIC model. Finally, we realise a FDTD/FDTD hybridization on two non coincident meshes for the 2D Maxwell-Vlasov system
Bourgeois, Pierre-Louis. « Modélisation de sources X générées par interaction laser-plasma en régime relativiste ». Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX073.
Texte intégralWhen an ultra-short ultra-intense laser impulsion propagates through a low density gas jet, a plasma is created and a bunch of electrons can be accelerated through laser wakefield acceleration to Gev energies in only a few centimetres. Those accelerated electrons then emit what is called Betatron radiation: a highly focused X-ray source with extremely good spatial and temporal properties, which has a lot of possible applications including ultra-high resolution imaging.In this thesis, we investigate possible improvements to one of the main numerical tools used to simulate those phenomenons: the Particle-In-Cell codes (CALDER). We have especially studied a numerical artefact called the numerical Cherenkov radiation, that occurs when relativistic particles move at speeds aproaching the speed of light in a vaccuum.We show that this artefact has a negative impact on the behaviour of the accelerated electron beam, especially on its transverse motion, which leads to important errors on the betatron radiation calculated using PIC simulations.We then introduce a new approach to mitigate the impact of this numerical Cherenkov radiation on laser wakefield acceleration simulation with a simple modification of the electromagnetic field interpolation method used in PIC codes. The results obtained with this new technique show a meaningful improvement on the electron motion wich becomes close to the theoretically expected behaviour.We then explore other possible applications for this new technique, notably improving the modelization of betatron sources, vacuum laser acceleration or direct laser acceleration.The improvement of the computation of the particles transverse motion thanks to this new method leads to more accurate results but also enables us to study physical phenomenon with subtle effects that would otherwise be hidden among the numerical noise of the simulation
Hägg, Martin. « Theoretical analysis and simulation of microwave-generation from a coaxial vircator ». Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-316595.
Texte intégralBlaclard, Guillaume. « Ultra-High Intense Laser on Dense Plasmas : from Periodic to Chaotic Dynamics ». Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS133.
Texte intégralThe advent of high power femtosecond lasers has paved the way to a promising and still largely unexplored branch of physics called Ultra-High Intensity physics (UHI). Once such a laser is focused on a solid target, the laser intensity I₀ can reach values as large as 10¹⁸⁻²⁰ W.cm⁻², for which matter is fully ionized. The plasma thus formed expands towards vacuum on a spatial scale characterized by a quantity Lg called the density gradient scale length. When Lg << λ₀ (laser wavelength), the dense plasma therefore acts as an optical mirror that specularly reflects the incident light: it is a plasma mirror. This remarkable physical system can be used in many scientific applications as compact source of high-energy and high-charge particle beams (electrons, ions) or bright source of radiations ranging from extreme ultraviolet-rays to X-rays through high harmonic generation processes. In order to finely control these sources, it is required to properly identify the different coupling mechanisms between light and matter at play during the interaction. In this manuscript, this has been made possible by performing accurate Particle-In-Cell (PIC) simulations with the WARP+PXR code. This recently developed code advances Maxwell’s equations in Fourier space, which proves to correctly model harmonic/electron emissions that standard codes fail to accurate describe even at high resolution. Based on WARP+PXR PIC simulations, we investigate the influence of Lg on the experimentally observed emission of light and particles, when a high-power laser pulse (I₀ = 10¹⁹ W.cm⁻²) reflects off a dense plasma. Our study reveals an unambiguous transition from a temporally periodic mechanism to a chaotic process as the interface becomes smoother. In particular, the latter mechanism, named stochastic heating, is fully characterized as well as its domain of validity in terms of laser-plasma parameters. In this regime, electrons in the underdense part of the gradient are exposed to the standing wave formed in front of the overcritical part of the plasma by superposition of incidence and reflected beams. While evolving in the two waves, electrons behave chaotically and absorb an important fraction of the laser energy. The nature of the interaction is revealed by reducing the equations of motion of particles in two waves to physical systems, such Kapitza’s pendulum, well-known to exhibit chaos. That correspondence gives deep physical intuitions on how electrons behave in different laser configurations, which allows us to predict major features of stochastic heating
Betar, Homam. « Kinetic Effects in Magnetic Reconnection ». Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0043.
Texte intégralPlasmas are gaseous systems of ions and electrons which interact via electromagnetic fields and display collective properties. Among these, is the notion of the magnetic line "connection". This expresses the fact that, in regimes in which charged particles spiral sufficiently fast along lines of magnetic induction, the latter is linked to the bulk plasma motion and acquire a topological identity which forbids them to break, intersect and reconnect. This topological identity, however, can be locally violated thanks to a number of kinetic effects, such as particle collisions, when the currents in the plasma are sufficiently intense: one speaks of "magnetic reconnection". Magnetic reconnection is an important ingredient of the plasma self-organization and has significance for both space and laboratory plasmas since it is at the basis of natural phenomena like solar flares and polar lights, or of disruptive processes in thermonuclear fusion experiments. A long-standing problem in the study of laboratory and astrophysical plasmas is to understand the mechanisms of acceleration of electrons and ions, as a magnetic field reconnect and release energy. In this work, we studied kinetic effects on reconnection instabilities developing spontaneously in static current sheets (tearing modes) and in combination with a class of kinetic instabilities (Weibel instabilities) that are relevant both to astrophysical plasma jets and to laser-plasma interaction experiments. We performed this study using reduced-fluid and kinetic models and we investigated the competition between tearing-type modes and Weibel-type instabilities by means of both semi-lagrangian full kinetic Vlasov-Maxwell simulations and particles in cell simulations
Jolivet, Laurent. « Étude de l'influence de l'émission électronique secondaire sur le phénomène de gaine et application aux propulseurs de satellite à effet Hall ». Toulouse, ENSAE, 2000. http://www.theses.fr/2000ESAE0020.
Texte intégralBaraka, Suleiman. « Etude de l'interactionentre le vent solaire et la magnetosphere de la Terre : Modele theorique et Application sur l'analyse de donnees de l'evenement du Halloween d'octobre 2003 ». Phd thesis, Université Pierre et Marie Curie - Paris VI, 2007. http://tel.archives-ouvertes.fr/tel-00138416.
Texte intégralFeister, Scott. « Efficient Acceleration of Electrons by an Intense Laser and its Reflection ». The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461225902.
Texte intégralCoche, Philippe. « Modélisation cinétique d’un propulseur à effet Hall ». Toulouse 3, 2013. http://thesesups.ups-tlse.fr/1995/.
Texte intégralHall effect thrusters are used for station-keeping of satellites in geostationary orbit. The originality of this kind of thruster is the use of a magnetic field which traps the electrons and creates a high electric field region. In this region, the ions are accelerated and extracted from the plasma to provide a thrust. Electron transport across the magnetic field lines is a major issue in predicting the thruster performance. Several transport mechanisms as collision phenomena and plasma turbulence have been identified to play a role but their exact contribution is still not clear. Based on two numerical particle models ("Particle-In-Cell"), composed of an explicit and implicit trajectory-tracking schemes, this work thesis aims at analyzing the proceeding of a discharge in order to isolate the transport mechanisms of electrons. It also aims at providing a better understanding of the plasma turbulence on the discharge behavior. We emphasize the strong unstationnary character of the discharge. We also study a particular transport mechanism, governed by turbulence and volumic collisions, using a particle-test numerical model
Kučera, Pavel. « USB host s mikrokontroléry PIC ». Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2010. http://www.nusl.cz/ntk/nusl-235542.
Texte intégralForestier-Colleoni, Pierre. « Etude expérimentale des champs magnétiques en surface d'une cible irradiée par laser et leurs implications sur le faisceau d'électrons ». Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0036/document.
Texte intégralThis thesis concerns magnetic fields, generated by the interaction between strong laser pulse (intensity up to1018 W/cm2) and solid target, and their effects on the fast electron beam. Indeed, the various magnetic fields created during this interaction can inuence the divergence of the fast electron beam. The magnetic field createdduring this interaction have a fundamental role on the fast electron beam characteristics : its source and its transportin the material. Diagnotics of polarimetry and crossed interferometry were developed during this thesis to observethe on-surface magnetic field of the target, and in particular, their spatial and temporal evolutions. Two types oftemporal evolution of the magnetic field were observed according to the contrast in intensity of the laser pulse : afast rise of magnetic field followed by a slower decrease created by the travel of the fast electrons in the material,and a slower growth of logarithmic form created by the pre-pulse of the laser by thermoelectric effect. The interpretation of our results obtained by these diagnotics allowed us to estimate the resistivity of the plasma.This resistivity named "anomalously high resistivity" in the literature can be explained by taking into account theinuence of the magnetic field on the electrons transport (creation of an anisotropy) and thus on the resitivity.The last diagnotic allowing the estimation of the magnetic field detailed in this thesis is the proton deectometry. itallows to observe the deviation of a proton beam during its propagation under the inuence of electric and magneticfields. Other experiments were focused on the fast electron beam divergence. Two main diagnotics were used : the K α imaging and the coherent transition radiation (C.T.R) imaging at the rear side of solid targets. These diagnoticsallowed to estimate the fast electron beam divergence for two distinct energetic electron populations. The differenceof divergence coming from characteristics of both diagnotics (electrons in charge of the emissions in different energies). The diagnotics of on-surface magnetic fields of target irradiated by intense laser, such as the technics of polarimetry and crossed interferometry developed in this thesis, are dedicated to be combined with diagnotics determining the evolution of the radial size of the fast electron beam generated by the laser-matter interaction. Their simultaneous use, and the correlation between their respective data, should allow to establish experimentally, in the short term, the inuence of the on-surface magnetic fields on the fast electron beam initial characteristics, in particular the angular and energy distributions. Our results of polarimetry on the spatio-temporal evolution of the magnetic fields of surface establish the state of the art for this type of measures. There are possible improvements, in particular as regards their use in conditions of irradiation by lasers of intensities > 1018 W/cm2. These perspectives are also the object of discussions in this manuscript
Pitsillides, Costas M. 1973. « Selective cell targeting with light-absorbing particles ». Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/89257.
Texte intégralDruma, Calin. « A particle in cell formulation for extrusion of fluoropolymers ». Ohio : Ohio University, 2003. http://www.ohiolink.edu/etd/view.cgi?ohiou1178048890.
Texte intégralAdams, Christopher Francis. « Assessment of magnetic particles for neural stem cell-based therapies ». Thesis, Keele University, 2015. http://eprints.keele.ac.uk/2494/.
Texte intégralAlmaghrabi, Mohammednoor Naher. « Flotation of coarse particles in a modified flotation column cell ». Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240560.
Texte intégralJenkins, Stuart Iain. « Applications of magnetic particles for oligodendrocyte precursor cell transplantation strategies ». Thesis, Keele University, 2013. http://eprints.keele.ac.uk/3821/.
Texte intégralValley-Omar, Ziyaad. « RNA transmission and expression from inert HIV candidate vaccine virus-like-particles ». Doctoral thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/4345.
Texte intégralIncludes bibliographical references (leaves 136-158).
HIV-1 Gag virus-like-particles (VLPs) produced in various expression systems are potent stimulators of both cellular and humoral immune responses in animal models. The encapsidation of large concentrations of random cellular RNA species is known to accompany the assembly of HIV virus particles. This RNA plays a crucial role by serving as a molecular scaffold for the assembly of Gag structural proteins into particles. Non-pseudotyped VLPs that do not present any HIV envelope glycoproteins are regarded as inert particles as they contain no replicative nucleic acid and are presumed to be unable to deliver encapsidated RNA for expression in inoculated individuals. Live virus cellular entry studies have shown that non-pseudotyped Gag particles are destined for degradation in acidified vesicles subsequent to receptor independent cellular entry. In addition to host cell RNA incorporation, Gag VLPs produced in insect cell-based, baculovirus expression systems have been observed to incorporate the baculovirus-derived Gp64 envelope glycoprotein. Gp64 has been shown to be efficient at enabling the delivery and expression of genes from recombinant baculoviruses and other Gp64 pseudotyped live viruses in mammalian cell lines both in vivo and in vitro. This study, therefore, set out to establish for the first time whether inert, baculovirus-derived (Gp64 pseudotyped) Gag VLPs could mediate delivery and expression of randomly encapsidated RNAs in mammalian cell lines.
Chaudhuri, Nazia. « The role of cell networks in response to diesel exhaust particles ». Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521907.
Texte intégralHopkins, Sally. « Applications of Sub-Micron Poly ( N-isopropyl acrylamide) Particles in Cell Culture ». Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522411.
Texte intégralHu, Bin. « Tissue engineering applications of selective activation of cell mechanosensitive receptors using magnetic particles ». Thesis, Keele University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.602978.
Texte intégralMarnett, Laura Ann. « The preparation of composite particles and their use in removal flow cell studies ». Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393944.
Texte intégralChen, Mu. « A study of polystyrene microgel particles with conjugated polymers and perovskite solar cell ». Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/a-study-of-polystyrene-microgel-particles-with-conjugated-polymers-and-perovskite-solar-cell(dc219cad-afc1-4a57-a8f8-87d22f9e97be).html.
Texte intégralLindemann, Dirk, Kristin Stirnnagel, Daniel Lüftenegger, Annett Stange, Anka Swiersy, Erik Müllers, Juliane Reh et al. « Analysis of Prototype Foamy Virus particle-host cell interaction with autofluorescent retroviral particles ». Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-176566.
Texte intégralLindemann, Dirk, Kristin Stirnnagel, Daniel Lüftenegger, Annett Stange, Anka Swiersy, Erik Müllers, Juliane Reh et al. « Analysis of Prototype Foamy Virus particle-host cell interaction with autofluorescent retroviral particles ». BMC, 2010. https://tud.qucosa.de/id/qucosa%3A28868.
Texte intégralDao, Thi Phuong Tuyen. « Hybrid polymer/liquid vesicles as new particles for drug delivery and cell mimics ». Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0190/document.
Texte intégralHybrid copolymer/lipid vesicle are recently developed self-assembled structures that could present biocompatibility and biofunctionality of liposomes, as well as robustness, low permeability and functionality variability conferred by the copolymer chains. However, to date, physical and molecular parameters governing copolymer/lipid phase separation in these hybrid membranes are not well understood. In this work, we studied in detail the formation and phase separation in the membranes of both Giant Unilamellar Hybrid Vesicles(GHUVs) and Large Unilamellar Hybrid Vesicles (LHUVs) obtained from the mixture of phospholipids in the fluid (liquid disordered) or gel state (solid ordered) with various copolymers based on poly(dimethylsiloxane) (PDMS) and poly(ethylene glycol) (PEO) with different architectures (grafted, triblock) and molar masses. For GHUVs, phase separation at the micron scale and nanoscale was evaluated through confocal microscopy, and Fluorescence lifetime imaging microscopy technique (FLIM) respectively, where as acombination of Small angle neutron scattering (SANS), Cryo-transmission electron microscopy (Cryo-TEM) and Time-resolved Förster resonance energy transfer (TR-FRET) techniques was used for LHUVs. We demonstrate that the lipid/polymer fraction, lipid physical state, and the line tension at lipid polymer/lipid boundaries which can be finely modulated by the molar mass and architecture of the copolymer are important factors that govern the formation and structuration of hybrid vesicles. We also evidence that elasticity ofthe hybrid membrane can be modulated via the lipid polymer composition, through the use of micropipettes techniques
QUATTROCCHI, NICOLETTA. « Biological camouflage imparts cell-like activity to injectable particles : the leukolike delivery system ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2011. http://hdl.handle.net/10281/20195.
Texte intégralHalsey, Richard James. « Construction and characterization of chimaeric human immunodefiency virus type 1 subtype C Gag virus-like particles ». Master's thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/4269.
Texte intégralIn this study I explored the possibility of making HIV-1 subtype C Pr55gag-based chimaeric virus-like particles (VLPs) as a boost to the HIV-IC multigene DNA vaccine pTHr.grttnC, which encodes a modified Gag-RT-Tat-Nef fusion protein (GRTTN). Furthermore, an attempt was made to produce VLP analogues to the HIV-IA polyepitope DNA vaccine pTHr.HIVA. A range of in-frame fusions with the C-termini of myristylation-competent p6-truncated Gag and native Pr55gag were made to test how the length of polypeptide and its sequence might affect VLP formation and structure.
Wang, Desheng. « CDSE Quantum Dots and Luminescent/Magnetic Particles for Biological Applications ». ScholarWorks@UNO, 2005. http://scholarworks.uno.edu/td/142.
Texte intégralMustafa, Kamal. « Cellular responses to titanium surfaces blasted with TiO₂ particles / ». Stockholm, 2001. http://diss.kib.ki.se/2001/91-628-4951-4/.
Texte intégralAhmed, Kawther Khalid. « Tumor cells surface-engineered with polymeric particles for use as cancer vaccines ». Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/6026.
Texte intégralBeck, Alexander J. « Determining Bed Failure Depth in Unconsolidated Submarine Sediments Using Particles in Cell Numerical Modeling ». Thesis, University of Louisiana at Lafayette, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10685053.
Texte intégralThe cause for low angle submarine landslide (SML) failures, at slope angles less than 4°, currently cannot be readily predicted using conventional terrestrial sources (i.e. excess pore pressure, weak horizons). Numerous models that have been developed pertaining to mass wasting on continental margins generally fall into two categories: post landslide occurrence (Tsunami wave run-up modeling) on coast lines and core sample description on costal margins. To date, there has been limited research on determining bed failure depth of submarine landslides through modeling. We propose a new method of 2D numerical modeling of rupture surface within unconsolidated sediments using the “Particle in Cell” method in combination with a conservative finite volume scheme. The software is written in Python, using the Numerical Python (NumPy) library to reach compiled-code-like performance. The Particle in Cell method was tested for accuracy, advection, and numerical diffusion. A set of six numerical model simulations are presented in which we investigate the role of material and external properties (i.e. hydraulic diffusivity and sedimentation rate), and geometry in the quest to determine bed failure depth. Through initial modeling simulations, it is confirmed that yield strength, diffusivity and sediment loading all play a role in predicting failure.