Дисертації з теми "Diamond laser"
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Neff, Clayton. "Mechanical Properties of Laser-Sintered-Nylon Diamond Lattices." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/6001.
Повний текст джерелаChen, Yu-Chen. "Laser writing of coherent colour centres in diamond." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:1b9fc247-3e35-457e-bfa5-d4ca474ac1ff.
Повний текст джерелаSharkey, Leo R. "Polishing of diamond films using an excimer laser." Connect to resource, 1996. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1192573096.
Повний текст джерелаWills, Jonathan B. "Laser diagnostics of chemical vapour deposition of diamond films." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251103.
Повний текст джерелаGottimukkala, Roja. "Growth and characterization of diamond and diamond like carbon films with interlayer." [Tampa, Fla] : University of South Florida, 2005. http://purl.fcla.edu/usf/dc/et/SFE0001405.
Повний текст джерелаLamprecht, GH, HGC Human, and LW Snyman. "Detection of diamond in ore using pulsed laser Raman spectroscopy." Elsevier, 2007. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000795.
Повний текст джерелаLamprecht, GH, HGC Human, and LW Snyman. "Detection of diamond in ore using pulsed laser Raman spectroscopy." Elsevier, 2006. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000856.
Повний текст джерелаRebello, Jagdish Hilary Diago. "Synthesis of Diamond by Selective Laser Excitation of Gaseous Precursors /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487928649986997.
Повний текст джерелаWilliams, Themistoklis. "Development of the diamond detector based real-time monitoring system for the ELI-NP gamma beam source." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS277/document.
Повний текст джерелаThis thesis discusses the development of a real-time monitoring system based on a diamond detector for the new gamma source being built in Magurele, Romania as part of the Extreme Light Infrastructure (ELI) project. The machine consists of an electron linear accelerator that branches into two lines, one at low energy between 80 and 320 MeV and one at higher energy going up to 720 MeV. On both lines, an optical recirculator leads a high power laser to collide with 32 electrons bunches to produce gamma rays by inverse Compton interaction. This machine is built by a European consortium named EuroGammaS, of which the "Laboratoire de l'Accélérateur Linéaire" is a member and tasked with developing most of the optical components. This is where I prepared the work presented in this manuscript. The electron bunches separated by 16 ns will collide with a circulating laser pulse at a rate of 100 Hz. To monitor the quality and stability of these interactions, the diamond detector system has been set-up. This involved simulation work on GEANT4 as well as two experiments to test the equipment at HiGS in the USA and newSubaru in Japan, two facilities that also offer gamma ray beams produced by inverse Compton scattering. The results obtained demonstrate the effectiveness of the system by analysing detection efficiency, charge collected or beam shape. This is promising in anticipation of the installation and commissioning expected for 2019
Lade, Robert James. "Pulsed ultraviolet laser ablation of carbon containing targets." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302156.
Повний текст джерелаMinami, Hideki. "Characterization of diamond-like carbon films produced by pulsed laser deposition." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0018/MQ47071.pdf.
Повний текст джерелаReilly, Sean. "Characterisation and implementation of synthetic diamond as a Raman laser material." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25764.
Повний текст джерелаDe, Feudis Mary. "Diamonds : synthesis and contacting for detector applications." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCD005/document.
Повний текст джерелаThis PhD work has been carried out in international cotutelle agreement between the University of Salento (L3, Italy) and the University of Paris 13 (LSPM, France). The main aim was the manufacturing of ohmic contacts on diamond surface for detector and electronic device applications. The work at L3 was dedicated to the laser-induced diamond graphitization process in order to produce graphitic electrodes on intrinsic diamonds. An experimental set-up dedicated to the laser writing technique on diamond has been developed in both hardware and software aspects and a protocol for the manufacturing of segmented graphitic contacts on diamond surface of large scale (cm²) has been implemented. An extensive characterization work has demonstrated the diamond-graphite phase transition and an ohmic electrical behaviour for the contacts with a resistivity of the order of ≈ 10⁻⁵ Ω.m. Eventually, an all-carbon detector has been developed and tested with 450 MeV electron and positron beams proving to be a good candidate in the role of active target for a new high-energy experiment (PADME) in the framework of the dark matter. The work at LSPM has been dedicated to the development of a protocol allowing reaching ohmic contacts on lightly boron doped diamond with oxygenated surface grown by MPACVD. The fabrication of Ti/Au metallic contact above a mesa structure has relied on a He ion implantation treatment to induce a graphitic layer underneath the diamond surface. The electrical measurements on lightly doped diamonds ([B] = 4 × 10¹⁷ cm⁻³) with metal or graphite / metal contacts have shown that the graphitic layer makes ohmic the contacts leading to a specific contact resistance as low as 3.3 × 10⁻⁴ Ω.cm²
Questo dottorato di ricerca è stato svolto in convenzione di cotutela internazionale tra l’Università del Salento (L3, Italia) e l’Università di Parigi 13 (LSPM, Francia). Il principale obiettivo è stato la fabbricazione di contatti ohmici su superficie di diamante per applicazioni come rivelatori e dispositivi elettronici. Il lavoro a L3 è stato dedicato allo studio del processo di grafitizzazione del diamante indotto da laser al fine di produrre elettrodi grafitici su diamanti intrinseci. In particolare, è stato sviluppato un apparato sperimentale dedicato alla tecnica di scrittura laser su diamante sia nelle componenti hardware che software, ed è stato realizzato un protocollo per la fabbricazione di contatti grafitici segmentati su superfici di diamante di grande scala (cm²). Un ampio lavoro di caratterizzazione ha dimostrato la transizione di fase diamante-grafite e il comportamento ohmico per i contatti elettrici con una resistività dell’ordine di 10⁻⁵ Ω.m. Pertanto, un rivelatore costituito solo di carbonio è stato sviluppato e testato con fasci elettronici e positronici di 450 MeV risultando essere un buon candidato nel ruolo di bersaglio attivo per un nuovo esperimento di fisica delle alte energie (PADME) nel contesto della materia oscura. Il lavoro a LSPM è stato dedicato allo sviluppo di un protocollo che ha consentito di ottenere contatti ohmici su diamanti leggermente drogati con boro e con superficie terminata con ossigeno, cresciuti mediante MPACVD. I processi di fabbricazione di contatti metallici Ti/Au sopra una struttura mesa sono stati sviluppato così come un trattamento di impiantazione a base di ioni di He al fine di indurre uno strato grafitico appena sotto la superficie del diamante. Le misure elettriche su diamanti leggermente drogati ([B] = 4 × 10¹⁷ cm⁻³) con contatti o solo metallici o grafitici / metallici hanno dimostrato che la presenza dello strato grafitico rende i contatti ohmici e comporta una resistenza specifica di contatto pari a 3.3 × 10⁻⁴ Ω.cm²
Smith, James Anthony. "Laser diagnostics of a diamond depositing chemical vapour deposition gas-phase environment." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247541.
Повний текст джерелаAlameer, Maryam. "Polarization Dependent Ablation of Diamond with Gaussian and Orbital Angular Momentum Laser Beams." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39850.
Повний текст джерелаMurphy, Steven. "An investigation of processing techniques and characterisation methods for 3D diamond detectors." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/an-investigation-of-processing-techniques-and-characterisation-methods-for-3d-diamond-detectors(186f03ff-d923-4fe7-bc27-dffd71e6bb36).html.
Повний текст джерелаSikora, Aurélien. "Incorporation de bore dans des films minces de « diamond-like carbon » : élaboration par ablation laser pulsé et caractérisations." Saint-Etienne, 2009. http://www.theses.fr/2009STET4018.
Повний текст джерелаThis work deals with the study of boron doped diamond-like carbon thin films elaborated by femtosecond and nanosecond laser ablation. The first aim of this work consists in identifying the potential applications of these films for sensors (for example thermometers). The second aim consists in correlating the films structure and properties with the deposition processes. The first chapter focused on the constitutive elements of the films: boron and carbon. Moreover, it presents a “state of the art” about DLC thin films and the different elaboration techniques. The second chapter deals with the experimental methods used for the elaboration and the study of the thin films. The third chapter deals with the structural and morphological characterizations. It highlights the important difference of structure of the films deposited by ns and fs PLD. Moreover, it underlines the structural modification due to the boron. The fourth chapter presents the study of the electrical and mechanical properties, as well as the tribological behaviour of the films. The structure difference of the films results in large variations of resistivity but does not change much the friction coefficient. The last chapter underlines the structural heterogeneity of the pure DLC films and focuses on the specificities of their extreme surface. This one turns out to be less dense and more conductor than the global film
Nikitin, Sergey. "Laser ultrasonics in a diamond anvil cell for investigation of simple molecular compunds at ultrahigh pressures." Thesis, Le Mans, 2015. http://www.theses.fr/2015LEMA1005/document.
Повний текст джерелаThis PhD research work is devoted to the use of laser ultrasound in high-pressure physics. The research is done using the recently established technique of laser ultrasonic measurements in a diamond anvil cell which allows investigation of the sound propagation and determination of the acoustic wave velocities at ultrahigh pressures. Time domain Brillouin scattering was applied here to depth-profiling of polycrystalline aggregate of ice compressed in a diamond anvil cell to megabar pressures. The technique allowed examination of characteristic dimensions of elastic inhomogeneities and texturing of polycrystalline ice in the direction, normal to the diamond anvil surfaces with sub-micrometer spatial resolution via time-resolved measurements of variations in the propagation velocity of the acoustic pulse travelling in the compressed sample. It was applied to measure the acoustic velocities in H2O ice up to 84 Gpa. The developed imaging technique provides, for each crystallite (or a group of crystallites) in chemically homogeneous transparent aggregate, usable information on its orientation as well as on the value of the elastic modulus along the direction of the sound propagation. This extends the basis for a successful application of highly developed micromechanical models of solids deformation at mbar pressure. On long term, such experiments extended to earth’s minerals and high or low temperatures would insure a significant progress in understanding of convection of the earth’s mantle and thus evolution of this and other planets
Cadot, Guillaume Bastien Jérémy. "Experimental and numerical investigations of diamond and related materials controlled-depth machining using pulsed laser ablation." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/46409/.
Повний текст джерелаKoivusaari, J. (Jarmo). "Structural, mechanical, and electronic properties of pulsed laser deposited carbon thin films and C-Si-heterojunctions." Doctoral thesis, University of Oulu, 2000. http://urn.fi/urn:isbn:9514257499.
Повний текст джерелаSikora, Aurélien. "Incorporation de bore dans des films minces de "Diamond-Like Carbon" : élaboration par ablation laser pulsée et caractérisation." Phd thesis, Université Jean Monnet - Saint-Etienne, 2009. http://tel.archives-ouvertes.fr/tel-00751337.
Повний текст джерелаConstantin, Loic. "Fabrication additive assisté laser de matériaux composites 3D et revêtement diamant par CVD." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0066.
Повний текст джерелаThe constant increase of the working frequency of semiconductor-based devices with their miniaturization led to severe overheating, which affect their lifetime and reliability. Hence, thermal management has become a significant concern for the microelectronic area and needs to be addressed. Diamond (D) is known to be an excellent material for thermal dissipation as it possesses one of the highest thermal conductivity (TC) of any natural material and has a high electrical resistivity. D can cool electronic chips in two ways. When used in the form of a film, D acts as a heat spreader. When utilized in powder-form, Ds can be introduced into metals to enhance their TC and bring dimensional stability at elevated temperatures. The resulting metal/D composite materials are thus, excellent component to form heat sinks. Naturally, the thermal performances of heat sinks are closely related to their surface area. Although the attractiveness of D-based materials in term of thermal performance, they often exhibit simple geometry mostly due to the complexity of machining D-based materials into intricated designs. Laser 3D printing is an emerging method of manufacturing sophisticated designs and has shown promising results for various metal and alloys. In this study, the laser 3D printing of copper/D composite materials is proposed to fabricate highly complex Cu/D structures which could remodel their applications. Before additively manufactured Cu/D composite materials, several challenges need to be addressed. First, the additive manufacturing of pure Cu is optimized and characterized. Then, due to a lack of a chemical affinity between Cu and D, the Cu-D interfacial zone is introduced in the composite material. Later, a molten salt coating process is studied to produced graded and multilayer coating of oxide/carbide and carbide/carbide, respectively, on carbon materials. Next, the additive manufacturing of highly sophisticated Cu/D composite structures is presented. Finally, the deposition of D films is performed by laser-assisted combustion flame. The effects of introducing ultraviolet lasers into the combustion flame are characterized in terms of chemical reaction and D film quality and growth rate
Lord, Oliver T. "Experimental Constraints on the Chemistry of the Earth's Core : Novel approaches using the Laser-Heated Diamond Anvil Cell." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520173.
Повний текст джерелаAprilis, Georgios [Verfasser], and Natalia [Akademischer Betreuer] Dubrovinskaia. "Pulsed laser heating in the diamond anvil cell : applications in geo- and material sciences / Georgios Aprilis ; Betreuer: Natalia Dubrovinskaia." Bayreuth : Universität Bayreuth, 2021. http://d-nb.info/1227444648/34.
Повний текст джерелаGarrelie, Florence. "Ablation laser femtoseconde pour le dépôt de couches minces." Habilitation à diriger des recherches, Université Jean Monnet - Saint-Etienne, 2008. http://tel.archives-ouvertes.fr/tel-00356315.
Повний текст джерелаDes nanoparticules ont été déposées par PLD femtoseconde, et incluses dans une matrice DLC. Des films de DLC dopés au nickel ou tantale (en raison de leur différente affinité chimique avec le carbone) ont été synthétisés. Deux différentes phases cristallines sont obtenues dans le cas du DLC dope Ta, avec la présence surprenante d'une phase métastable β-Ta, qui est corrélée aux propriétés du plasma. La présence de carbure de tantale est également mise en évidence sur les bords des clusters de tantale.
Les films de DLC pur et de DLC dopé aux métaux sont caractérisés pour l'application aux électrodes pour biocapteurs, avec une sensibilité élevée et une faible limite de détection. L'optimisation avec l'incorporation d'un autre dopant, tel que le bore est discutée.
La possibilité d'utiliser ces couches de DLC dopé au bore pour des capteurs thermiques et nanocalorimétriques est étudiée dans le cadre d'un projet ANR. Les thermomètres à base de DLC avec un fort TCR (Coefficient de Température de Resistance) sont intégrés dans des structures suspendues, et montrent de bonnes propriétés.
Dans la dernière partie de ce mémoire, les perspectives envisagées pour ce travail sont présentées, avec l'introduction d'une mise en forme temporelle de l'impulsion laser femtoseconde et d'une boucle adaptative d'optimisation. Ces premiers travaux mettent bien en évidence les potentialités de cette technique, pour le dépôt couches minces et la synthèse de nanoparticules, permettant un contrôle de la nature et de l'énergie cinétique des particules du plasma. La suite de ce travail envisage donc de mieux comprendre les effets d'une mise en forme temporelle de l'impulsion laser femtoseconde sur les propriétés des produits d'ablation et donc des couches minces élaborées.
Bourquard, Florent. "Ablation laser femtoseconde assistée d’une mise en forme temporelle pour le dépôt de couches minces et la synthèse de nanoparticules." Thesis, Saint-Etienne, 2013. http://www.theses.fr/2013STET4022/document.
Повний текст джерелаThis work explores the control of ultrafast laser ablation plume composition and kinetics by temporal shaping of femtosecond laser pulses. The goal is the optimization of thin films and nanoparticles deposition. Chapter 1 is a synthesis of the literature on femtosecond laser deposition of thin films. The focus is on Diamond-Like Carbon films and nanoparticles. The impact of laser temporal pulse shaping on the ablation mechanisms is developed. Ablation plume diagnostic methods are detailed. Chapter 2 describes the experimental setup for temporal pulse shaping and plasma diagnostic. The latter is done through space and time-resolved optical emission spectroscopy and extinction spectroscopy. Chapter 3 reports on the impact of doubles pulses and long pulses on aluminium and boron ablation plumes. Ion yield enhancement in aluminium ablation plasma is explained through hydrodynamics simulations. In chapter 4, various temporal pulse shapes are used for graphite ablation and Diamond-Like Carbon thin films deposition. The control of the plume kinetics is reached by selectively populating the various plume speed components: molecules, atoms, ions. Even though the deposited Diamond-Like Carbon structure is unaffected, it has been observed an improvement of the thin films surface. Chapter 5 shows the efficiency and sensitivity of optical extinction spectroscopy for in situ measurement of nanoparticles size distribution in femtosecond laser ablation plumes
Kelly, Mark. "Laser diagnosis and computer modelling of C/H/O and C/H/N plasmas used in diamond chemical vapour deposition." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.653079.
Повний текст джерелаColeman, Amy Louise. "Studies of dynamically and statically compressed antimony." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31334.
Повний текст джерелаCayzac, Witold. "Ion energy loss at maximum stopping power in a laser-generated plasma." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00949958.
Повний текст джерелаMakela, Mark F. "Polarized Ultracold Neutrons: their transport in diamond guides and potential to search for physics beyond the standard model." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/26194.
Повний текст джерелаPh. D.
Torresin, Olivier. "Etude comparée de l'émission d'électrons de nanopointes de tungstène et de diamant : émission de champ et photoémission induite par laser femtoseconde." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30253.
Повний текст джерелаThis thesis presents electron emission from metallic (tungsten) and dielectric (diamond) nanotips under femtosecond laser illumination. The behavior of DC emission and laser induced photoemission from tungsten nanotips has been widely studied and we use it to benchmark diamond measurements. In the first part, we study DC emission and photoemission from tungsten nanotips. Numerical simulations made from a finite element model (using COMSOL) of our experimental setup, allow the computation of static and optical field enhancement coefficients linked to the tip geometry. Results are compared with the spatial profile of electron emission, which links the field enhancement area at the tip apex and the electron detection area. In the second part, we study DC emission and photoemission from diamond nanotips. Electron energy measurements highlight the presence of a voltage drop along the diamond tip, due to the low conductivity of this material. Electron emission current inside the tip and at the apex obeys Poole-Frenkel conduction, coupled with Fowler-Nordheim field emission observed commonly for metallic surfaces. We propose a macroscopic model to combine conduction and emission mechanisms for DC emission. Under laser illumination, emission measurements are very different from the metallic case. Electron emission saturates under intense laser illumination. In this regime, we show that the DC current cannot reach its DC value between pulses. By lowering laser repetition rate, we are able to measure the dynamics of the DC current in between laser pulses. We adapt the DC macroscopic model for laser induced photoemission using an effective capacitance, and we show very good quantitative agreement with experimental measurement obtained on diamond nanotips. The last part is an introduction to electron time-of-flight measurements to measure the temporal statistics of electron arrival times. We present the modifications made on the experimental setup to be able to make these kinds of measurements, as well as preliminary results obtained on DC and laser-induced emission from tungsten nanotip
Borz, Mario. "Propriétés d'émission et de conduction de nano-pointes de diamant sous éclairement laser ultra-bref : Etude par microscopies à effet de champ et spectroscopie en énergie." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR117.
Повний текст джерелаThe aim of this thesis is to understand the changes in the electrical and optical properties of large band-gap materials at the nanoscale in the presence of a huge static electric _eld. Diamond nano-needle has been chosen as a study material, thanks to its wide band gap, high resistance to external stress and high thermal conduction. Diamond presents also high electrical resistance, making it a good candidate for the study of electrical conduction modi_cations under high electric and optical _elds. In order to study the electrical conduction properties, two di_erent experimental tech- niques were used: Field Ion microscopy and Field Emission Microscopy with and without laser illumination. The experimental observations were coupled with electrical conduction models which describe qualitatively and quantitatively the obtained results. For the study of the optical properties, laser-assisted Field Emission Microscopy was performed. In this case, the study was performed in two experimental con_gurations: one by illuminating the whole sample by the laser beam and the other by focusing the laser beam only on the apex of the nano-tip where the electric _eld is enhanced and the electrons are emitted into vacuum. The results describe the electrical conduction and electron emission properties of the diamond nano-needles in dark and under laser illumination. As _eld emitters, diamond nano-needles show advantages compared to metallic tips such as: higher emission stability and higher damage threshold under laser illumination. The results are promising for the development of novel photo-electron sources for time- resolved electron microscopy
Kupenko, Ilya [Verfasser], and Leonid [Akademischer Betreuer] Dubrovinsky. "Portable laser-heating system for experiments with diamond anvil cells and its application to studies of geophysically important materials / Ilya Kupenko. Betreuer: Leonid Dubrovinsky." Bayreuth : Universität Bayreuth, 2014. http://d-nb.info/1063995558/34.
Повний текст джерелаKonôpková, Zuzana. "Thermal Conductivity of Materials under Conditions of Planetary Interiors." Doctoral thesis, Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-150396.
Повний текст джерелаFedotenko, Timofey [Verfasser], and Natalia [Akademischer Betreuer] Dubrovinskaia. "Laser heating setup with high-magnification imaging for studies of physical and chemical phenomena up to ultra-high pressures in diamond anvil cells / Timofey Fedotenko ; Betreuer: Natalia Dubrovinskaia." Bayreuth : Universität Bayreuth, 2021. http://d-nb.info/1240309643/34.
Повний текст джерелаHrubiak, Rostislav. "Exploring Thermal and Mechanical Properties of Selected Transition Elements under Extreme Conditions: Experiments at High Pressures and High Temperatures." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/696.
Повний текст джерелаBenchikh, Épouse Sbaï Nadia. "Couches minces nanostructurées de carbone amorphe dopées ou alliées : Elaboration par ablation laser femtoseconde et Caractérisations." Phd thesis, Université Jean Monnet - Saint-Etienne, 2005. http://tel.archives-ouvertes.fr/tel-00142211.
Повний текст джерелаL'ablation laser en régime femtoseconde est la technique utilisée pour la synthèse des couches minces de DLC dopées ou alliées. Ce sujet met également en évidence l'apport de cette technique sur les propriétés morpho-structurales et physiques des DLC dopés ou alliés.
Bourquard, Florent. "Ablation laser femtoseconde assistée d'une mise en forme temporelle pour le dépôt de couches minces et la synthèse de nanoparticules." Phd thesis, Université Jean Monnet - Saint-Etienne, 2013. http://tel.archives-ouvertes.fr/tel-01063802.
Повний текст джерелаĆmiel, Milan. "VÝVOJ NÁSTROJŮ S PKD, CVD VRSTVOU A CVD POVLAKEM PRO DOKONČOVÁNÍ DĚR." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228661.
Повний текст джерелаMammei, Russell Rene. "Thin Films for the Transport of Polarized Ultracold Neutrons for Fundamental Symmetry Study." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/28714.
Повний текст джерелаUCN guides facilitate the transfer of UCN from the source to the spectrometer. Common guide materials include stainless steel, copper, aluminum, and quartz. Often a thin film is applied to these components to increase their ability to transport/bottle and preserve the polarization of UCN. In the region of the SD2 UCN source, nickel-58 films are applied, whereas once the UCN are polarized, diamond-like carbon (DLC) films are employed. This dissertation covers the application, process developments, and characterization of these coatings. In addition a study concerning the surface finish resulting from the mechanical polishing and electropolishing of the guides that make up the UCNA beamline is presented.
Ph. D.
Hamad, Hassan. "Détermination des coefficients d'ionisation de matériaux à grand gap par génération multi-photonique." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0017/document.
Повний текст джерелаIn the last few decades, the use of wide bandgap (WBG) semiconductors (silicon carbide SiC, gallium nitride GaN, diamond, etc…) has become popular in the domain of power electronics. Their electronic and mechanical characteristics made of the WBGs a good alternative to the traditional silicon. However, additional studies are mandatory to improve the breakdown voltage, static and dynamic losses, and the performance at high temperature of the WBG devices. In this context, two specific experimental benches OBIC (Optical Beam Induced Current) -under development- are set up during this thesis. OBIC method consists to generate free charge carriers in a reverse biased junction by illuminating the device with an appropriate wavelength. An OBIC signal is measured if the charge carriers are generated in the space charge region. After a first phase of preparation and adaptation of the experimental environment, OBIC measurements led to demonstrate the multi-photonic generation by illuminating a SiC junction with a green laser (532 nm). OBIC measurements allowed giving an image of the electric field at the surface of the diode: OBIC presents a non-destructive analysis to study the efficiency of the peripheral protection and to detect the defects in the semi-conductor. Minority carrier lifetime was also deduced by studying the OBIC decrease at the edge of the space charge region. Ionization rates were extracted using OBIC method; these coefficients are key parameters to predict the breakdown voltage of the devices. OBIC measurements were also realized on the GaN, and two-photon generation was highlighted by measuring an OBIC current in the diamond when illuminating it with a UV laser beam (349 nm)
Mashhadikarimi, Meysam. "Obtaining triple layer polycrystalline diamond compact by HPHT method." PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, 2017. https://repositorio.ufrn.br/jspui/handle/123456789/23749.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
Neste trabalho de pesquisa, foi obtido um compacto de diamante policristalino (PDC), constitu?do de uma camada superior de diamante policristalino sob um substrato de WC-10% em peso de Co e uma interface de WC-20% em peso de Nb/Ni entre as camadas, atrav?s de m?todo de sinteriza??o de alta press?o e alta temperatura (HPHT). Para alcan?ar esse objetivo, foram realizadas tr?s etapas distintas. Na primeira etapa, foi sinterizado o corpo de diamante com um ligante adequado, e foram obtidos os melhores par?metros de sinteriza??o. Na segunda etapa, foi realizado o estudo de diferentes condi??es de sinteriza??o para o substrato de metal duro WC-10% p.Co. E, na terceira e ?ltima etapa, foi produzido, de acordo com os resultados alcan?ados nas etapas anteriores, o compacto de diamante policristalino de camada tripla (PDC). Na primeira etapa, quatro ligantes diferentes foram usados para sinterizar o diamante atrav?s do m?todo HPHT. Os ligantes utilizados foram o Nb/Fe, Nb/Co, Nb/Ni e Nb puro, sendo 10% em peso de ligante utilizado para cada composi??o. A sinteriza??o foi realizada a diferentes temperaturas e sob diferentes press?es e tempos. As amostras obtidas foram analisadas atrav?s das medidas de densidade relativa e dureza, al?m das imagens eletr?nicas de varredura, para encontrar os melhores par?metros de sinteriza??o e ligante. Os estudos mostraram que o Nb apresentou o melhor comportamento, e que os melhores par?metros de sinteriza??o foram: T = 1750 ?C, P = 7,7 GPa, t = 6 minutos. Na segunda etapa, uma mistura em p? de WC-10% em peso de Co foi sinterizado atrav?s de HPHT sob press?o de 7,7 GPa, variando temperatura (1500 ?C, 1600 ?C, 1700 ?C, 1800 ?C, 1900 ?C) e tempo (2 e 3 minutos). As an?lises microestruturais e estruturais foram realizadas atrav?s de MEV/EDS e DRX. Ensaios de dureza, tenacidade (ITF) e de resist?ncia ? compress?o, tamb?m, foram realizados para entender os efeitos de diferentes par?metros de sinteriza??o nas propriedades dos sinterizados, verificando-se densifica??o total das amostras sinterizadas a altas temperaturas. Entretanto, foi observado um crescimento anormal de gr?os para estas mesmas temperaturas. Altos valores de dureza foram observados, aproximadamente, entre 1250 a 1650 HV para todas as amostras sinterizadas. Na terceira etapa, para a obten??o do PDC, uma camada fina de WC-20% em peso de Nb/Ni foi utilizada para a forma??o da interface entre a camada superior de diamante com ligante de Nb pura e o substrato de WC 10% em peso de Co. A sinteriza??o foi feita atrav?s do m?todo HPHT ? temperatura de 1750 ?C sob 7,7 GPa de press?o. Foram utilizados dois tempos diferentes, de 6 min. (tr?s sucessivos 2 minutos) e 9 min. (tr?s sucessivos 3 minutos). A dureza foi medida e os estudos estruturais/microestruturais foram realizados atrav?s de an?lises de MEV/EDS. Em suma, os resultados mostraram que este novo tipo de PDC pode ser produzido com sucesso, usando um novo ligante, o niobio puro, para o diamante, sem qualquer presen?a de grafitiza??o. Verificou-se tamb?m que o uso de uma interface com os mesmos elementos constituintes do substrato e do corpo de diamante sinterizado resultou numa boa ades?o entre as camadas, o que pode resultar em melhor desempenho e melhorar a durabilidade do PDC.
The primary objective of this thesis was to obtain a triple layer polycrystalline diamond compact (PDC) containing a polycrystalline diamond as top layer, a WC 10 wt% Co substrate, and a WC 20 wt% Nb/Ni interface to bond these two layers via high pressure high temperature (HPHT) sintering. To achieve this objective, the project has been done in three different stages. The first stage was producing diamond sintered body with a suitable binder, and finding the best sintering parameters. The second stage of project was done to study the WC 10 wt% Co hardmetal substrate at different sintering conditions, and the third and last stage was done according to the results achieved from previous stages to obtain a triple layer PDC. At the first stage, four different binders were used to sinter diamond under HPHT condition. Binders were Nb/Fe, Nb/Co, Nb/Ni and pure Nb and 10 wt% binder was used. Sintering was carried out at different temperature and under different pressure and holding time. Obtained samples were studies according to relative density, microstructure, and hardness to find the optimum binder and sintering parameters. Studies at this stage showed that Nb is the best binder and T=1750 ?C, 7.7 GPa with holding time more than 6 minutes are the best sintering parameters. At the second stage a powder mixture of WC 10 wt% Co was sintered via HPHT at 1500, 1600, 1700, 1800, and 1900?C under 7.7 GPa pressure for 2 and 3 minutes. Microstructural/structural analyses were performed by SEM/EDS and XRD and hardness, Indentation Fracture Toughness (ITF) and compression tests were also carried out to understand effects of different sintering parameters. At this stage, it was found that full density can achieved for high sintering temperature along with abnormal grain growth. High hardness was observed in range starting from 1250 up to 1650 HV. At the third stage, to obtain PDC, a thin layer of WC 20 wt% Nb/Ni was used as an interface between top layer of diamond with pure Nb binder and WC 10 wt% Co substrate. Sintering was done via HPHT method at 1750?C under 7.7 GPa of pressure. Two different holding time of 6 (three successive 2 minutes) and 9 (three successive 3 minutes) were used. Hardness was measured and microstructural/structural studies were done via SEM/EDS. The overall results showed that this new kind of PDC can successfully produce using a new pure Niobium binder for diamond without any graphitization. It was also found that using an interface having the resemblance to both substrate and sintered diamond body caused good adhesion between layers that can results in enhanced performance and improving durability of PDC.
Kitabayashi, Hiroyuki. "Surface acoustic wave filters on diamond layered structures /." *McMaster only, 2001.
Знайти повний текст джерелаDe, vecchy Jon. "Réalisation de substrats innovants à partir de diamant." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALT022.
Повний текст джерелаWithin a global aim of reducing energy consumption, microelectronics components must be more efficient and less energy-consuming. Power electronics, which converts electric power, is particularly concerned because its component must operate at high intensity, voltage and temperature. Silicon, the base material of these components, is reaching its limits and the conception of components made with other materials is currently being studied. Among the candidate materials, diamond and its outstanding properties is of great interest. Its excellent thermal conductivity (2200 W/m/K) combined with high breakdown field (10 MV/cm) and high hole mobility (2000 cm²/V/s) are attractive for making smaller and more efficient components.However, monocrystalline diamond synthesis methods are limiting substrate size to about 15 x 15 mm², thus preventing its industrialization. The approach developed in this thesis is the diamond layer transfer to another substrate by adapting the Smart Cut^TM process. This process is based on a combination of ion implantation and bonding of the implanted substrate to a receiving substrate. Annealing then causes the fracture of the implanted substrate and the detachment of a film (with controlled thickness) which is transferred to the receiving substrate. This approach would make it possible to reduce component cost by decreasing diamond consumption and to open the way to industrialization thanks to successive transfers on a large substrate.Smart Cut^TM must be fully adapted to the diamond case, studies of each step will thus be presented. Blistering observation on the implanted substrate surface after annealing is the very first step of ion implantation parameters adaptation. A blistering process using combinations of hydrogen ion implantation and annealing will be presented.Diamond transformations occurring during the process will be characterized. Full layer transfer studies using substrate bonding will then be presented. Finally, prospects for optimization and realization will be given
Hallock, Samuel H. "Viability of using diamond field emitter array cathodes in free electron lasers." Thesis, Monterey, California : Naval Postgraduate School, 2010. http://edocs.nps.edu/npspubs/scholarly/theses/2010/Jun/10Jun%5FHallock.pdf.
Повний текст джерелаThesis Advisor(s): Lewellen, John ; Swent, Richard. "June 2010." Description based on title screen as viewed on July 13, 2010. Author(s) subject terms: Free Electron Lasers, Field Emitter Arrays, Cathode Test Cell, FEL, Diamond Field Emitter Array, Cathode. Includes bibliographical references (p. 71-72). Also available in print.
Sprague, Michael R. "Raman memory for entanglement in diamonds and light storage in optical fibres." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:7f3d03f3-d47d-4871-8d59-268b301e1b8d.
Повний текст джерелаBirch, Rolf. "Progress towards high power, high brightness microchip lasers : multi-watt operation using diamond heatspreaders." Thesis, University of Strathclyde, 2011. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=16841.
Повний текст джерелаRémy, Benjamin. "Mesure de propriétés thermophysiques de matériaux minces et de dépôts par méthode Flash : application aux films polycristallins de diamant." Vandoeuvre-les-Nancy, INPL, 1998. http://www.theses.fr/1998INPL020N.
Повний текст джерелаBrygoo, Stéphanie. "Chocs laser sur le diamant, l'hélium et l'hydrogène : une étude expérimentale de la Warm Dense Matter." Palaiseau, Ecole polytechnique, 2006. http://www.theses.fr/2006EPXX0037.
Повний текст джерелаSilva, Vlamir Oliveira da [UNESP]. "Influência da técnica de preparo cavitário na microinfiltração marginal em restaurações de dentes decíduos." Universidade Estadual Paulista (UNESP), 2000. http://hdl.handle.net/11449/104285.
Повний текст джерелаO objetivo desse trabalho foi avaliar a influência da forma do preparo cavitário na microinfiltração marginal em restaurações em dentes decíduos. Foram preparadas canaletas medindo 2,0 mm nas faces vestibular e lingual de molares decíduos que foram divididas aleatoriamente em 3 grupos de acordo com a técnica de preparo cavitário: Grupo I - alta rotação associado à ponta diamantada; Grupo II - sistema de abrasão a ar; e Grupo III - laser Er:YAG. Após o condicionamento com ácido fosfórico por 15 segundos, foi utilizado o adesivo Single Bond (3M) e a resina Filtek Flow (3M) para restaurar as canaletas. Os espécimes foram então mantidos em estufa a 37ºC por 6 dias, termociclados (500 ciclos com temperatura variando entre 5 e 55ºC), isolados e colocados em solução de fucsina básica à 0,5% durante 24 horas. Após serem seccionados a microinfiltração foi avaliada em microscópio ótico ligado a uma câmera de vídeo com 10 X de aumento. Para se avaliar a forma das cavidades medimos os ângulos oclusal, cervical e de abertura das cavidades, bem como a largura e a profundidade das mesmas por meio de fotomicrografias obtidas em MEV. Os resultados demonstraram semelhança estatística entre as larguras dos preparos cavitários, porém os ângulos oclusal, cervical e de abertura das cavidades apresentaram-se diferentes estatisticamente e que não houve microinfiltração marginal em nenhum dos grupos avaliados e que a diferença na forma de preparo das cavidades não influenciou na microinfiltração marginal dos espécimes estudados.
The aim of this research was the evaluation of the cavity prepare technique on the marginal microleakage in deciduous teeth. Cavities measuring 2.0 mm were prepared on the buccal and lingual faces and were divided into three groups according to the cavity prepare technique: Group I - High speed associated to diamond bur; Group II - air abrasion system; and Group III - Er:YAG laser. After the phosphoric acid etching for 15 seconds, the Single Bond (3M) adhesive and te Filtek Flow (3M) were used for the restoration of the cavities. Then the sample was stored at 37ºC for 6 days, termocycled (500 cycles with temperature varying from 5 to 55º C), isolated and immersed in a 0.5% funcsin solution for 24 hours. After being sectioned the microleakage was examined with a magnification optical microscope connected to a color video camera. In order to evaluate the shape of the cavities the occlusal, cervical and cavity opening angles were measured, as well as the width and depth of then, using SEM photographs. The results showed that there was no marginal microleakage in any of the evaluated groups and that the difference in the cavity shape did not influence the marginal infiltration on the studied samples.