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Dissertations / Theses on the topic 'SiC nanoparticles'

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Author: Grafiati
Published: 10 December 2022
Last updated: 29 January 2023

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1

Strandqvist, Carl. "The Functionalization of Epitaxial Graphene on SiC with Nanoparticles towards Biosensing Capabilities." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-120502.

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Graphene has been shown to be very powerful as a transducer in many biosensor applications due to its high sensitivity. This enables smaller surfaces and therefore less material consumption when producing sensors and concequently cheaper and more portable sensors compared to the commercially available sensors today. The electrical properties of graphene are very sensitive to gas exposure why presence of molecules or small changes in concentration could easily be detected when using graphene as a sensing layer. Graphene is sensitive towards many molecules and in order to detect and possibly identify gas molecules the surface needs to be functionalized. The intention of this project was to use nanoparticles (NPs) to further increase sensitivity and specificity towards selected molecules and also enable biofunctionalization of the NPs, and by that tune the electrical properties of the graphene. This study proposes the use of Fe3O4 and TiO2 NPs to enable sensitive detection of volatile gases and possibly further functionalization of the NPs using biomolecules as a detecting agent in a liquid-phasebiosensor application. The interaction between graphene and NPs have been investigated using several surface charactarization methods and electrical measurements for detection of gaseous molecules and also molecules in a liquid solution. The characterizing methods used are XPS, AFM with surface-potential mapping and Raman spectroscopy with reflectance mapping in order to investigate the NPs interaction with the graphene surface. Sensors where manufactured for gas-phase detection of CO, formaldehyde, benzene and NH3 specifically and display differences in sensitivity and behavior of the Fe3O4 and TiO2 NPs respectively. For liquid measurements the difference in behavior in two buffers was investigated using an in-house flow-cell setup. The surface charecterizing measurements indicated that just a small difference could be found between the two NPs, however a significant change in sensor response could be detected as a function of coverage. The liquid and gas-phase measurements rendered information on differences in sensitivity between the NPs and between analytes where TiO2 showed a higher level of sensitivity towards most of the gases investigated. Both Fe3O4 and TiO2 NP coated graphene showed capability to detect formaldehyde and benzene down to 50 ppb and 5 ppb respectively. The sensitive gas detection could help protecting individuals being exposed to a hazardous level of volatile gases if concentrations increase rapidly or at a long term exposure with lower concentrations, improving saftey and health where these gases are present.
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2

Pinate, Santiago. "Study of particle-current-electrocrystallization interactions in electroplating of Ni/SiC coatings." Licentiate thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Material och tillverkning, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-43548.

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Composite coatings have great potential due to the possibility to combine properties of two different materials in one coating. This way, new surface properties can be tailored and applied to any material's surface. Among different manufacturing routes, electrodeposition has the biggest potential in creating composite metal matrix coatings, especially nanocomposites. Nevertheless, there is a knowledge gap between the deposition of composite coatings in laboratory conditions, described in the literature, and those that are now in place on an industrial level. While micro-composites have been industrialised for about ten years, the production of Ni/SiC nanocomposite coatings by electroplating is still far from an industrial manufacturing floor. This is due to the lack of understanding of the mechanisms of nanoparticles codeposition leading to scattering results. The production of nanocomposite coatings is much more sensitive to the process parameters compared to microcomposite. The correlation between parameters and their influence on the codeposition are still not fully identified and understood. The codeposition models proposed in the literature are only valid in specific conditions, but composite depositions behave differently, or even opposite if some of the variables are modified. The main objective of this work is to identify the particle-current-electrocrystallization interactions in the production of Ni/SiC nanocomposites. A series of experiments are designed to isolate single variables and identify the controlling parameters of these interactions and their impact on the final properties. In this thesis, the effect of current density, type of current and particles size are identified as primary variables controlling the metal crystallisation and coatings properties. Among many parameters, a specific current waveform in pulse reverse mode proved to increase the codeposition rate effectively, doubling the content of nanoparticles compared to other techniques. Ultrasound assistance is also considered as stirring method when particles are suspended in the deposition bath to increase their stability and dispersion. The effect of Ultrasound on the particles codeposition and metal crystallisation is studied and compared to silent condition. Moreover, a surface treatment for the particle has been proven successful in making any particle to behave similarly in the Ni deposition bath. Furthermore, the codeposition rate doubled or tripled compared to untreated ones thanks to this treatment. Both ultrasonic agitation and surface treatment reduce the formation of aggregates, improving the particle dispersion and metal microstructure thus increasing the final hardness. The work proved the synergistic effect between particle and metal microstructure which affected the final properties of the coating. Therefore, when tailoring the composite coating to improve hardness, it is not only the amount of the particles that should be considered but also their influence on the electrocrystallisation process.
Kompositbeläggning har stort potential tack vare möjligheten att kombinera två material i samma ytskikt. På detta sätt kan nya ytegenskaper skräddarsys och appliceras på ett materials yta. Elektrodeposition är den tillverkningsmetod som har störst potential att uppnå kompositbeläggningar, i synnerhet nanokompositer. Ett kunskapsgap existerar mellan elektrodeposition under laboratorieförhållanden, som beskrivet i vetenskaplig litteratur, och hur processen går till i industriell miljö. Medan industriell tillämpning av mikrokompositer pågått ungefär tio år, så har produktion av Ni/SiC nanokompositbeläggningar fortfarande inte nått fabriksgolvet. Detta är en konsekvens av bristande förståelse kring mekanismer för samdeposition av nanopartiklar som leder till varierande resultat. Produktion av nanokompositbeläggningar är mycket mer känslig för processparametrar jämfört med mikrokompositer. Korrelationer mellan parametrar och dess inverkan på samdeposition är fortfarande inte fullt identifierade och förstådda. Modeller för samdeposition som föreslås i vetenskaplig litteratur är endast giltiga under särskilda förhållanden. Kompositdeposition kan uppvisa avvikande eller till och med motsatt beteende om variabler förändras. Huvudmålet med detta arbete är att identifiera interaktioner mellan partikel, ström och elektrokristallisering under tillverkning av Ni/SiC nanokompositer. En serie av experiment är utvecklade för att isolera variabler och identifiera de parametrarna som kontrollerar dessa interaktioner och dess inverkan på ytans egenskaper. I denna avhandling identifieras strömtäthet, typ av ström, och partiklars storlek som primära variabler som kontrollerar metallkristallisering och beläggningens egenskaper. Bland många parametrar, visades en specifik vågform på strömmen i omvänd pulsläge öka samdepositionen effektivt, ledande till en fördubbling av andelen nanopartiklar jämfört med andra tekniker. Ultraljud tillämpades som metod för omrörning av depositionsbadet för förbättrad stabilitet och fördelning. Effekten av ultraljud på samdepositionen av metallkristallisering studeras och jämfört med tyst tillstånd. Dessutom har en ytbehandling för partiklarna visats framgångsrik för att få godtyckliga partiklar att bete sig likt Ni i depositionsbadet. Detta ledde till att samdepositionens takt ökade med en faktor av två till tre jämfört med obehandlade partiklar. Både ultraljud och ytbehandling av partiklarna ledde till minskad aggregation vilket förbättrade fördelningen av partiklar och metallstruktur och därigenom ökad hårdhet. Arbetet bevisar synergieffekten mellan partiklar och metallstruktur vilket påverkar beläggningens slutliga egenskaper. Vid utveckling av nya ytbeläggningar ska därför inte bara mängden partiklar beaktas utan även dess interaktion med elektrokristalliseringsprocessen.
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3

Sengele, Armelle. "Décontamination et dépollution par photocatalyse : réalisation d'un dispositif d'élimination d'agents chimiques toxiques et de polluants dans l'air et dans l'eau." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF066/document.

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Ce travail de thèse consiste à synthétiser des nanoparticules de dioxyde de titane pour la décontamination d’agents chimiques par photocatalyse. L’objectif principal est d’optimiser le photocatalyseur pour la dégradation du sulfure de diéthyle (DES), simulant de l’ypérite. L’oxydation du DES produit des sulfates qui empoisonne le TiO2. Le but est donc de limiter cette désactivation ainsi que le rejet de molécules toxiques. Une solution est d’augmenter la surface spécifique par deux méthodes : le dopage du TiO2 au tantale ou à l’étain et l’ajout d’un porogène lors de la synthèse par voie sol-gel. Les catalyseurs optimisés présentent des taux de conversion élevés pour l’élimination du DES en phase gazeuse sous flux continu grâce à leur surface spécifique importante et leurs propriétés d’adsorption. Les matériaux les plus performants sont ensuite immobilisés sur des mousses tridimensionnelles de β-SiC. Ces média photocatalytiques se désactivent mois rapidement que les matériaux pulvérulents. Une régénération par une solution de soude permet de retrouver leur activité initiale. Ce qui permet une utilisation industrielle possible des catalyseurs. Cette thèse ouvre la voie à la réalisation d’un prototype de décontamination de l’air pour l’élimination d’agents chimiques de guerre
This work consists in the synthesis of titanium dioxide nanoparticles for the decontamination of chemical warfare agents by photocatalysis. The main goal is to optimize the photocatalyst to eliminate diethylsulfide (DES), simulating yperite. The oxidation of DES generates sulfates that lead to the poisoning of TiO2. Thus, the aim is to limit this deactivation and to avoid a release of harmful products. A solution is to increase the specific suface area by two methods: doping TiO2 with tantalum or tin and adding a porogen during the sol-gel synthesis. These optimized catalysts exhibit high conversion rates for DES elimination in the gas phase under a continuous flow thanks to their high specific surface area and their adsorption properties. The best catalysts are immobilized on tridimensional β-SiC foams. These photocatalytic foams deactivates slower than the TiO2 powders. A regeneration by an NaOH solution can restore their initial activity. It allows a possible industrial application for these catalysts. This thesis opens the way to realize a decontamination prototype for air to eliminate chemical warfare agents
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4

Al-Sid-Cheikh, Maya. "Impact des oxydes de fer naturels et des nanoparticules manufacturées sur la dynamique des éléments traces dans les sols de zones humides." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S144.

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La nanoscience est basée sur les changements de propriétés des particules lorsque leur diamètre est inférieur à 100 nm (i.e. nanoparticules, NPs). Devant l’utilisation croissante de tels NPs, et leur déversement probable dans l’environnement, l’évaluation de leurs risques sur la santé humaine et l’environnement est un enjeu majeur. Dans le cadre de la protection des eaux et des sols, l’évaluation de la qualité des eaux de surface est particulièrement importante, notamment dans les zones humides (ZHs), où la dynamique des métaux toxique (i.e. As, Pb, Ni, Cr, Hg) est complexe et dépend des conditions redox du milieu. Comme les NPs de magnétite (nano-Fe3O4), naturelles ou manufacturées, sont reconnues pour leur capacité d’adsorption importante face aux métaux lourds, leurs interactions dans les ZHs ripariennes (ZHRs) avec les ETMs restent critiques quant à leurs impacts directs ou indirects. Ainsi, l’objectif de cette thèse était d’étudier le rôle des nano-Fe3O4 manufacturées (~10nm) et des oxydes de fer naturels sur la dynamique des ETMs dans les eaux de surfaces et les sols de ZHRs. Ainsi, dans un premier volet portant sur des précipités colloïdaux naturels provenant de produits de reoxydation en milieu riparian (soumis à des oscillations redox), la distribution spatiale des éléments a été effectuée par cartographie isotopique nanoSIMS (i.e. 75As-, 56Fe16O-, le soufre (32S-) et la matière organique (12C14N-), alors que la spéciation du soufre a été évaluée par adsorption des rayons X au seuil K du soufre (S) (XANES). Ces analyses ont permis de mettre en évidences les interactions entre les oxydes de fer naturels, la matière organique naturelle (MON) et un métalloïde toxique, l’arsenic. Nos résultats suggèrent, par colocalisation statistique des images nanoSIMS, l’existence de deux types d’interaction : (1) 12C14N-, 32S-, 56Fe16O- et 75As-, et (2) 12C14N-, 32S- et 75As-. La coexistence des formes de S oxydées et réduites, confirmées par les analyses XANES, pourrait être attribuée à la lente cinétique d’oxydation de la MON. Ainsi, ce premier volet montre qu’en plus des interactions MON, oxydes de fer et As, de possibles interactions directes entre As et NOM à travers des groupements fonctionnels soufrés (e.g. thiols) sont aussi possibles en milieu oxydé. Dans un second volet, l’effet des nano-Fe3O4 (~ 10 nm) sur la mobilité des éléments traces (ETs) et des colloïdes, dans l'horizon organominéral d’un sol naturel de ZHR, a été évaluée à l’aide de colonnes de sol. Nos résultats montrent que l’enrobage des nanoparticules semble influencer la mobilité de la MON et des ETs du sol. En effet, la mobilité des ETs semble augmenter en présence de nano-Fe3O4 nus, suggérant des associations où la MON stabiliserait les nanoparticules et augmenterait leur mobilité ainsi que celle des ETs associés
Nanoscience is based on changes in particle properties when their diameter is below 100 nm (ie nanoparticles, NPs). Considering the increasing use of such NPs and their discharge into the environment, the assessment of their risks to human health and the environment is a major issue. Underneath the protection of waters and soils, the surface water assessment quality is particularly important, especially in wetlands, where the toxic metals dynamic (e.g. As, Pb, Ni, Cr , Hg) is complex and depends on the redox conditions of the environment. As magnetite (nano-Fe3O4), a natural or manufactured NP, is known for its significant adsorption capacity with heavy metals, their interactions in riparian wetlands with trace metals (TMs) remain critical concerning their direct of indirect impact on trace metals (TMs) mobility. The objective of this thesis was to study the role of manufactured nano-Fe3O4 (~ 10nm) and natural iron oxides on the TMs dynamics in wetland surface waters and soils. Therefore, in a first part considering natural colloidal precipitates from reoxidation products from riparian areas (subject to redox oscillations), a spatial distribution of elements was performed using nanoSIMS isotope mapping (i.e. 75As-, 56Fe16O-, sulfur (32S-) and organic matter (12C14N-), while the sulfur speciation was evaluated X-ray adsorption at K edge of the sulfur (S) (XANES). These analyzes allowed to highlight the interactions between natural iron oxides, natural organic matter (NOM) and a toxic metalloid, As. Our results suggest, with a statistical colocalization of nanoSIMS images, the existence of two interaction types: (1) 12C14N-, 32S-, 56Fe16O- and 75As-, and (2) 12C14N-, 32S- and 75As-. The coexistence of the oxidized and reduced forms of S, confirmed by the XANES analyses might be attributed to the slow oxidation kinetic of MON. Thus, this first part shows that in addition to the known interactions between MON, iron oxides and As, a possible direct interaction between As and NOM through sulfur functional groups (e.g. thiols) are also possible in oxidized environment. In a second part, the effect of nano-Fe3O4 (~ 10 nm) on trace elements (TEs) and colloids mobility in the organomineral horizon of a natural wetland soil was assessed using soil columns. Our results show that the nanoparticles coating influences the mobility of NOM and TMs. Indeed, the TMs mobility increases in presence of naked nano-Fe3O4, suggesting associations where NOM stabilizes the nanoparticles and increase the nanoparticles and associated TMs mobility. This mechanism seems less possible with coated nano-Fe3O4 where MON blocks the coating adsorption sites and therefore the adsorption of metals
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Matras, Jan. "Aplikace reaktivních nanočástic do SAC pájecí pasty." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377074.

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This work is a research on the topic of reactive nanoparticles and their agitation into the solder paste, which it also describes. It describes in detail the properties of each solder alloys. It explains the creation of intermetallic layers in the soldering process and examines their structure. It also focuses on the evaluation and methodology of testing the properties of solder pastes. In the practical part, individual tests are performed with PF606 and PF610 solder paste.
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Lin, Yu-Pu. "Functionalization of two-dimensional nanomaterials based on graphene." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4727.

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Cette étude de la fonctionnalisation de graphène se base principalement sur la monocouche de graphène épitaxiée sur SiC. Les propriétés électroniques, structurales et les compositions chimiques du graphène fonctionnalisé sont étudiées. L'incorporation d'azote dans le graphène réalisée par les procédures à base de plasma montre un décalage de niveaux inoccupés du graphène vers EF , obtenue par les analyses spectroscopie de photoémission inverse en résolution angulaire. Ce dopage-n est attribué à la présence de graphitique-N. De plus, la configuration des espèces de N substitués dans le graphène peut être contrôlée efficacement par l'énergie, les espèces d'azote incidentes, et l'épaisseur du graphène de départ. L'hydrogénation de la couche tampon de graphène (BLG) à température variante sature les liaisons pendantes de Si de l'interface différemment, soit par la formation de nouvelles liaisons C-Si à température ambiente, soit par les hydrogènes intercalés. Le BLG devient fortement-isolant dans le premier cas, et devient une monocouche de graphène quasi-autoportante (QFSG) dans le second, permettant un nouveau concept de fabrication des dispositifs à base de graphène sur SiC. La réaction/couplage entre des molécules pi-conjugué et les graphène vierge ou fonctionnalisé est aussi étudiée. Les états inoccupés des molécules à base de perylene sont légèrement modiffiées sur le graphène dopé N à cause d'un renforcement de transfert de charge. Des réactions chimiques entre les molécules perylenes et le graphène sont observées aprés l'exposition aux électrons de basse énergie. En résumé, cette étude permettra une meilleure maîtrise des propriétés des matériaux 2D comme le graphène
In order to promote 2D materials like graphene to their numerous applications, new methodsaltering their electronic and chemical properties have to be mastered. In this thesis, theprocesses of chemical doping and hydrogenation of monolayer graphene grown on SiC are investigated. Nitrogen atoms are successfully substituted in the graphene lattice using plasma-basedmethods. The bonding configurations of the incorporated N can be controlled via the nature and energy of exposing species and the thickness of the pristine graphene. An n-type doping, revealed by angle-resolved inverse photoemission spectroscopy (ARIPES), is found in most N-doped graphene and is assigned to the presence of graphitic-N. Hydrogenations of the buffer layer of graphene (BLG) on SiC at ambient or high temperatures saturate the remaining Si dangling bonds at BLG/SiC interface in two different ways, either by inducing additional C-Si bonds or by H intercalation. This results in 2D materials with distinct characters, an insulating, graphane-like H-BLG or a quasi-free-standing graphene, which may be used as a new concept for the engineering of graphene-based devices. The interactions between pi-conjugated molecules and the functionalized graphene are also investigated. The unoccupied states of molecules are altered by the presence of incorporated N, but the degradation of molecules due to low-energy electron exposure seems not enhanced by the doping nitrogen under the studied conditions. Nevertheless, the functionalization of graphene is demonstrated and its electronic and chemical properties are carefully studied, which should help to faster further applications employing functionalized graphene
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Ditto, Andrew James. "Biodegradable Nanoparticles for Use as an Inhalable Antimicrobial and as a Receptor Targeted Delivery Device." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1280335303.

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McKenzie, Lallie Cobb. "Mechanistic insights on nanoparticle formation : investigation of reaction pathways and development of controlled synthesis for triphenylphosphine-stabilized undecagold /." Connect to title online (ProQuest), 2009. http://proquest.umi.com/pqdweb?did=1798969441&sid=1&Fmt=2&clientId=11238&RQT=309&VName=PQD.

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Pawluk, Tiffany. "Iridium nanoparticles : a density functional theory study /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1075692711&sid=20&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Sandra, Fabien. "Elaboration de matériaux céramiques poreux à base de SiC pour la filtration et la dépollution." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20015.

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En 1920, le moteur Diesel marque l'histoire en se faisant une place dans le milieu de l'automobile. Toutefois, malgré la révolution que représente le moteur Diesel notamment en terme de technologie (moteur à combustion interne dont l'allumage n'est pas commandé mais spontané par phénomène d'auto-inflammation (absence de bougie d'allumage)), des inconvénients majeurs subsistent, tout particulièrement au niveau environnemental et sanitaire (émission de gaz à effet de serre, prélèvement accru d'énergie fossile, impact direct sur la santé). Afin de lutter contre ces émissions, l'Union Européen à mit en place les normes EURO (depuis 1993) incitant les constructeurs automobiles à concevoir des procédés d'élimination des particules carbonées et à apporter des évolutions au niveau des motorisations. C'est dans ce contexte qu'a vu le jour la technologie Filtre à Particules initié par Peugeot en 1999 pour évoluer d'années en années jusqu'à être considérées aujourd'hui comme une avancée majeur en terme de traitement des particules Diesel. Encore aujourd'hui les problèmes d'émanations demeurent en raison des imbrûlés générés par le moteur diesel (suies, HC aromatiques polycycliques, d'oxyde de soufre, d'oxyde d'azote…). Les dégagements de particules de suies fines demeurant un problème particulièrement important au niveau de la santé. Cette thèse s'inscrit dans l'optique d'optimisation du procédé FàP en proposant l'élaboration de membrane à base de SiC supportée. Plus généralement, notre étude concerne l'élaboration de céramiques poreuses (membranes supportées et mousses) à base de silicium pour application environnementale et sanitaire (Filtration des particules fines, dépollution et séquestration de CO2).Le Chapitre I traite du contexte général de l'étude. La problématique des émissions de particules est abordée d'un point de vue sanitaire et environnemental en précisant les normes en vigueurs pour leur contrôle. La technologie FàP est décrite avant d'introduire le SiC et la voie dite des « polymères précéramiques » (PDCs). L'aspect catalytique est ensuite abordé avant de développer le principe d'élaboration de membrane SiC et leur intérêt pour une application de dépollution automobile.Le Chapitre II traite de l'élaboration de membranes SiC supportées. L'étude concerne l'élaboration d'un procédé optimale pour déposer une membrane au sein de la porosité du FàP qui modifierait les caractéristiques de porosité de ce dernier sans pour autant engendrer des répercussions néfastes sur la filtration. Le polymère précéramique, précurseur de SiC, sera alors décrit et nous étudierons sa mise en forme par la technique dite de « trempage-tirage » (dip-coating) afin d'élaborer, après pyrolyse, une membrane SiC. Cette dernière sera caractérisée par de nombreux outils expérimentaux.Le Chapitre III reprend le procédé d'élaboration des membranes de SiC élaboré dans le Chapitre II mais il proposera d'aller plus loin avec la réalisation et l'étude de catalyseurs pour la combustion des suies, et leur intégration au sein d'une microémulsion de type SiC-MxOy utilisée pour revêtir les FàP.Le Chapitre IV propose une étude sur la préparation de mousses à base de SiC. Ce chapitre d'aspect plus fondamental consistera à développer des mousses cellulaires et à porosité hiérarchisée à base des éléments silicium (Si), bore (B), carbone (C) et azote (N). Cette phase de carbonitrure de silicium et de bore (Si/B/C/N) sera élaborée par couplage de la voie PDCs avec soit des agents sacrificiels soit par réplication. Une étude préliminaire sur la séquestration de CO2 sera alors décrite pour finir
Since the 90's, Diesel engines are widely used though they are criticized because of the pollution emitted. The constant updates of the Europeans norms (since 1993) concerning the diesel emissions imply a perpetual improvement of filtration techniques. The Diesel Particles Filter (DPF) technology used by the car manufacturer PSA Peugeot Citroën is one of the best ways to fulfill the limitation for diesel emissions. However, particles emission issue is still a problem and future legislations more and stricter, so an improvement of the DPF process is required to respect them. In this context, we have considered the elaboration of two different types of porous membranes on the DPF channels. The first one was in SiC, and had the aim to enhance the filtration efficiency. In this way, the smallest particles matter could be locked in the filter. The second kind of membrane integrates a catalytic phase inside the ceramic matrix, so in addition to the filtration aspect, it could improve soot combustion during the regeneration step of the DPF.The first chapter of my thesis deals with the literature corresponding to the subject, i.e. the DPF technology, non-oxides Si-based ceramics, and in particular those obtained through polymer-derived ceramics route (also called PDCs route). Then, ceramic coatings and catalytic phases are also treated. In the second chapter, we have considered the PDCs route and preceramic polymers to elaborate a SiC coating inside the DPF channels. We employed the dip-coating technique to overlay the channel surface with the AHPCS precursor of SiC (allylhydridopolycarbosilane), then, a pyrolysis under argon allows obtaining a SiC coating, in order to decrease the average pore diameter of the DPF (keeping an efficient filtration while avoiding overpressure) to catch soot nanoparticles evolving from Diesel engine.The third part of my PhD deals with the elaboration of another kind of coating for the DPF channels including a catalytic phase in the ceramic membrane. For this purpose, the microemulsion synthesis has been considered to prepare SiC-MxOy membrane. Further, we incorporated various catalytic phases based on Ce, Fe and Pt as activators of soot combustion. By employing the dip-coating technique, we successfully covered the DPF channels of our monoliths with the aforementioned microemulsion and after a heat treatment under controlled atmosphere; a porous coating consisting of the catalytic phase and the ceramic matrix was obtained. From this film, the porosity has been modified by lowering the diameter of the initial pores, but also by getting an additional porosity due to the polymer conversion and the surfactant decomposition. Catalytic sites in the ceramic have improved the soot combustion by lowering the temperature of the combustion.The fourth chapter introduces the elaboration of porous SiBCN materials through two approaches, replication and warm-pressing with sacrificial template (polymethylmethacrylate, PMMA). The SiBCN ceramic is a promising material due to its high mechanical properties and its stability at high temperature (1700-1800°C). By coupling the PDCs way with those two techniques, we are able to elaborate SiBCN porous materials which features can be tuned according to the technological application envisaged
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Ceylan, Abdullah. "Core/shell structured magnetic nanoparticles synthesized by inert gas condensation." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 139 p, 2007. http://proquest.umi.com/pqdweb?did=1397915001&sid=7&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Mi, Changwen. "Nanoparticles under the influence of surface/interface elasticity." Laramie, Wyo. : University of Wyoming, 2006. http://proquest.umi.com/pqdweb?did=1296091581&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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Fox, James Brent. "A study of nanoparticle aggregation using novel x-ray and permeability techniques a thesis presented to the faculty of the Graduate School, Tennessee Technological University /." Click to access online, 2008. http://proquest.umi.com/pqdweb?index=33&sid=1&srchmode=1&vinst=PROD&fmt=6&startpage=-1&clientid=28564&vname=PQD&RQT=309&did=1605147081&scaling=FULL&ts=1251313913&vtype=PQD&rqt=309&TS=1251313928&clientId=28564.

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Helgeson, Matthew E. "Structure, rheology, and thermodynamics of wormlike micelle-nanoparticle mixtures." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 536 p, 2009. http://proquest.umi.com/pqdweb?did=1818417471&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Thesis (Ph.D.)--University of Delaware, 2009.
Principal faculty advisors: Norman J. Wagner, Dept. of Chemical Engineerin; and Eric W. Kaler, College of Engineering. Includes bibliographical references.
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Renaud, Adèle. "Semi-conducteurs de type p pour une application en cellules solaires à colorant." Nantes, 2013. https://archive.bu.univ-nantes.fr/pollux/show/show?id=bc5d055e-878e-4b2d-af7c-44949293c4df.

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Les travaux de thèse portaient sur la réalisation de cellules à colorant de type p (DSSCp) avec une photocathode autre que NiO. L’objectif était de remplacer ce semi-conducteur de type p par des matériaux plus transparents, plus conducteurs et présentant une bande de valence plus basse en énergie pour permettre de générer des tensions en circuit ouvert (VOC) plus élevées. Dans ce cadre, les composés CuGaO2, LaOCuS et ZnO:N ont été synthétisés sous la forme de nanoparticules, caractérisés par diffraction des rayons X et leurs potentiels de bandes plates (Vbp) déterminés par spectroscopie d’impédance complexe. Il en résulte que CuGaO2, LaOCuS et ZnO:N présentent respectivement des Vbp nettement supérieur (0,49 V/ECS), similaire (0,26 V/ECS) et inférieure (0,20 V/ECS) à celui de NiO (0,33 V/ECS). Naturellement, des cellules à colorant à base du matériau de la famille des delafossites ont été réalisées et testées avec la dyade PMI-NDI comme colorant et un complexe de cobalt comme médiateur rédox. Une VOC supérieure à celle observée pour NiO dans les mêmes conditions a été mis en évidence. Ce résultat est malheureusement terni par un courant en court-circuit (Jsc) moindre. Pour tenter de remédier à cet inconvénient, des matériaux CuGaO2:Mg avec des surfaces spécifiques supérieures à celle de CuGaO2 ont été réalisés et testés. Parallèlement, nous nous sommes attachés à la réalisation de cellules à base de LaOCuS, autrement plus conducteur que NiO, tandis que la conductivité de type p de ZnO:N a été caractérisée plus en profondeur
These thesis works focused on the realization of p-type dye sensitized solar cells (DSSCp) with a photocathode using an alternative to NiO. The objective was to replace the p-type semiconductor by more transparent and conductive materials and displaying a lower valence band energy to enable the generation of higher open circuit voltages (Voc). In this context, CuGaO2, LaOCuS and ZnO:N compounds were synthesized in nanoparticles form, characterized by X-ray diffraction and their flat band potentials (Vfb) were determined by complex impedance spectroscopy. As a result CuGaO2, LaOCuS and ZnO:N have Vfb significantly higher (0. 49 V/SCE), similar (0. 36 V/SCE) and lower (0. 20 V/SCE) than that of NiO (0. 33 V/SCE). Thus, dye sensitized solar cells based on the delafossite material were made and tested with the PMI-NDI dyad as dye and a cobalt complex as redox mediator. A greater VOC than that observed for NiO under the same conditions is highlighted. This result is unfortunately altered by a lower short circuit current (Jsc). To try to overcome this drawback, CuGaO2:Mg materials with a higher specific surface area than that of CuGaO2 have been prepared and tested. Simultaneously, we have focused on the achievement of cells based on LaOCuS, more conductive material than NiO. In addition, the p-type conductivity of ZnO:N was further characterized
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Martinson, Carol A. "Evaluation of cupric oxide (CuO) nanoparticles in the removal of arsenic species from groundwater across a wide range of natural conditions." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1594490421&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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Yan, Zhicheng. "Structural, microstructural, and magnetic properties of terbium, gadolinium, and samarium cobalt nanoparticles." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 216 p, 2009. http://proquest.umi.com/pqdweb?did=1833641681&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Xiao, Li. "Structural and electronic properties and applications of platinum and gold nanoparticles /." Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1342740081&sid=3&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Angelos, Sarah Ann. "Molecular machines supported on mesoporous silica nanoparticles for drug delivery applications." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1835827851&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.

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Dziedzic, Tomasz. "Electrochemistry of layer-by-layer films containing redox active MnO₂ nanoparticles." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1798480871&sid=2&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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Opitz, Armin Walter. "Structural and functional investigations of a molecular imaging nanoparticle for magnetic resonance imaging of oncogene expression in the pancreas." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 490 p, 2008. http://proquest.umi.com/pqdweb?did=1459924631&sid=13&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Thesis (Ph.D.)--University of Delaware, 2008.
Principal faculty advisors: Norman J. Wagner, Dept. of Chemical Engineering, University of Delaware; Eric Wickstrom, Dept. of Biochemistry and Molecular Biology, Thomas Jefferson University. Includes bibliographical references.
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22

Erdem, Ayça. "Short-term toxicity of photocatalytic titanium dioxide to bacteria under ambient conditions." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 204 p, 2008. http://proquest.umi.com/pqdweb?did=1679680941&sid=14&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Cromwell, Jaya. "Advances in nanoparticle contrast agents for magnetic resonance imaging /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 56 p, 2008. http://proquest.umi.com/pqdweb?did=1597632781&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Lin, Ming-Yu. "Interactions between titanium dioxide nanoparticles and algal cells at moderate particle concentration." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 98 p, 2008. http://proquest.umi.com/pqdweb?did=1597633661&sid=17&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Patlolla, Kiran Kumar. "Free vibration analysis: comparison between continuum mechanics and molecular mechanics models a thesis presented to the faculty of the Graduate School, Tennessee Technological University /." Click to access online, 2009. http://proquest.umi.com/pqdweb?index=0&did=1786737281&SrchMode=1&sid=2&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1268928551&clientId=28564.

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Mullaugh, Katherine M. "Formation and persistence of cadmium sulfide nanoparticle in aqueous solution." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 232 p, 2009. http://proquest.umi.com/pqdweb?did=1885682071&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Li, Guifeng. "Syntheses and functionalizations of magnetic iron oxide nanoparticles for applications in organic chemistry /." Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1328058811&sid=3&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Wang, Hongli. "A study of the structural, microstructural and magnetic properties of iron-platinum and cobalt-platinum type nanoparticles." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 200 p, 2007. http://proquest.umi.com/pqdweb?did=1354136761&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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29

Kearns, Gregory Justin. "Engineering interfaces at the micro- and nanoscale for biomolecular and nanoparticle self-assembled devices /." view abstract or download file of text, 2007. http://proquest.umi.com/pqdweb?did=1417810561&sid=2&Fmt=2&clientId=11238&RQT=309&VName=PQD.

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Thesis (Ph. D.)--University of Oregon, 2007.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 158-174). Also available for download via the World Wide Web; free to University of Oregon users.
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Chou, Hsun-Wen. "Nanotoxicology from nano titanium dioxide particle size effect on Ceriodaphnia dubia to death mechanism /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 77 p, 2008. http://proquest.umi.com/pqdweb?did=1597633671&sid=14&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Chatterjee, Abhijit. "Nanoscale modeling and control of self-assembled nanoparticle arrays using a hierarchy of multiscale models." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 407 p, 2007. http://proquest.umi.com/pqdweb?did=1397912451&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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32

Foster, Evan Wayne. "Self-assembly of extended, high-density gold nanoparticle monolayers on silicon dioxide /." view abstract or download file of text, 2006. http://proquest.umi.com/pqdweb?did=1188875831&sid=1&Fmt=2&clientId=11238&RQT=309&VName=PQD.

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Thesis (Ph. D.)--University of Oregon, 2006.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 173-182). Also available for download via the World Wide Web; free to University of Oregon users.
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Fan, Jinda. "Syntheses and surface modifications of gold and iron oxide nanoparticles for organic and biomedical applications /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1140192751&sid=11&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Duanmu, Chuansong. "Expanding applications of iron oxide nanoparticles by surface functionalization : from magnetic resonance imaging to nano-catalysis /." Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1967917191&sid=4&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Buzby, Scott Edward. "The effect of doping titanium dioxide nanoparticles on phase transformation, photocatalytic activity and anti-bacterial properties." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 120 p, 2008. http://proquest.umi.com/pqdweb?did=1459918071&sid=9&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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36

Jespersen, Michael L. "Engineering the macro-nano interface : designing the directed self-assembly and interfacial interactions of gold nanoparticle monolayers. /." Connect to title online (ProQuest), 2007. http://proquest.umi.com/pqdweb?did=1525704531&sid=1&Fmt=2&clientId=11238&RQT=309&VName=PQD.

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Thesis (Ph. D.)--University of Oregon, 2008.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 164-192). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
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37

Alvarenga, Marinho Andre Luiz. "Development of catalytic process for biogas upgrading : study of structure and oxygen mobility on Ni and Pt nanoparticles encapsulated catalysts." Thesis, Poitiers, 2020. http://www.theses.fr/2020POIT2272.

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Le reformage à sec du méthane (DRM) est un procédé catalytique permettant de produire, à partir de biogaz issu de la dégradation de la biomasse, du gaz de synthèse (CO + H2) dont les applications industrielles sont nombreuses. La formation de coke et le frittage des sites actifs métalliques sont les principaux problèmes à résoudre pour amener cette technologie à l’échelle industrielle.Ce travail de thèse vise à étudier l’effet de l’encapsulation de Ni au sein de deux structures différentes : nanoparticules incluses dans une matrice ou distribuées dans un support mésoporeux. Les résultats montrent que les particules de Ni incluses dans CeO2 améliore la résistance au frittage lors de la réduction à haute température (800°C) et entraine une plus forte interaction métal-support. Le dopage de la cérine par Zr inhibe la croissance des particules de Ni et augmente la mobilité de l’oxygène comme révélé par les expériences d’échange isotopique. Le dopage par Gd ou Sm n’améliore ni la stabilité thermique du matériau ni le frittage des sites métallique. L’échange du Ni par le Pt préserve l’effet promoteur lié à l’inclusion du site actif dans la matrice oxyde ainsi que la mobilité de l’oxygène. Des oxydes mixtes mésoporeux CeO2-Al2O3 contenant du Ni ont été préparés par la méthode d’auto-assemblage induit par évaporation (EISA). Après réduction, des particules de Ni de petites tailles sont observées (<5 nm). Un comportement différent se produit lorsque le Ni est imprégné a posteriori sur le support CeO2-Al2O3 préparé par EISA à cause de la présence de particules de Ni plus larges et isolées qui promeuvent la réaction de décomposition de CH4.L’absence de dépôts carbonés après 24 h de réaction sur Ni@CeZrO2 ou après 72 h de réaction sur 10Ni-CeO2-Al2O3 confirme l’intérêt de ces catalyseurs pour la transformation du biogaz en gaz de synthèse par reformage à sec du méthane
Dry reforming of methane (DRM) is a catalytic process able to convert the biogas generated from biomass degradation into syngas, which has many industrial applications. However, coke formation and metal sintering are the main drawbacks to upgrade this technology to an industrial scale. This work evaluates the effect of Ni encapsulation in two different structures: embedded nanoparticles and distributed nanoparticles over mesoporous support. Results showed that Ni embedded in ceria improved the resistance to sintering along the reduction at high temperature (800 °C) and led to a higher metal-support interaction compared to impregnated catalyst. Doping ceria with Zr inhibited the growth of CeO2 and Ni clusters in embedded catalysts and increased the oxygen mobility as revealed by oxygen isotopic exchange experiments. The doping with Gd and Sm did not enhance thermal stability on the material and the sintering is still observed. The nature of metal exchanging Ni by Pt did not affect the promotional effects of encapsulation in embedded structures. Ni-based mesoporous mixed CeO2-Al2O3 oxide catalysts prepared by one pot Evaporation Induced Self Assembly (EISA) presented small metallic Ni particles (< 5 nm). Different behavior occurs with CeO2-Al2O3 oxide prepared by EISA method when Ni is post-impregnated because of the presence of isolated larger Ni particles which promotes the decomposition of CH4. Finally carbon deposits were not detected over embedded Ni@CeZrO2 after 24 h of reaction and meosoporous 10Ni- CeO2-Al2O3 after 72 h of reaction and, therefore, these catalysts presented promising results in this work for biogas upgrading process by dry reforming of methane reaction
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Clark, Michael A. "Effect of nanoparticles on friction and wear of 2-D and 3-D carbon-carbon composite disc brakes /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1095432851&sid=8&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Thesis (M.S.)--Southern Illinois University Carbondale, 2005.
"Department of Mechanical Engineering and Energy Processes." Includes bibliographical references (leaves 84-86). Also available online.
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Kang, Seung Hyun. "Engineered E. coli and its application in bioremediation and nanotechnology." Diss., UC access only, 2009. http://proquest.umi.com/pqdweb?index=59&did=1871853251&SrchMode=1&sid=2&Fmt=7&retrieveGroup=0&VType=PQD&VInst=PROD&RQT=309&VName=PQD&TS=1270148636&clientId=48051.

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40

Panday, Namuna. "Scanning Ion Conductance Microscopy for Single Cell Imaging and Analysis." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3477.

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Most biological experiments are performed on an ensemble of cells under the assumption that all cells are identical. However, recent evidence from single cells studies reveals that this assumption is incorrect. Individual cells within the same generation may differ dramatically, and these differences have important consequences for the health and function of the entire living body. I have used Scanning Ion Conductance Microscopy (SICM) for imaging and analysis of topographical change of single cell membrane, which is difficult to be revealed by optical microscopes. Morphological change in the fixed and live HeLa cell membrane during endocytosis of conjugated polymer nanoparticles was studied. Results demonstrated SICM is a powerful tool to study the interaction between nanoparticle and cell membrane during internalization of nanoparticles through the membrane. This research can improve our fundamental understanding of cellular behavior and will be helpful for drug delivery applications. Based on conventional SICM, we have developed a novel method to simultaneous map the topography and potential distributions of the single living cells membranes. At the first step, multifunctional nanopipettes (nanopore/nanoelectrode) have been fabricated and characterized. To demonstrate the potential sensing capability and understand the mechanism, I measured the ionic current and local electric potential change during translocation of 40 nm charged gold nanoparticles. Our results reveal the capability of the multifunctional probe for the highly sensitive detection of the ionic current and local electrical potential changes during the translocation of the charged entity through the nanopore. From the potential change, we revealed the dynamic assembly of GNPs before entering the nanopore. The experimental results are also nicely explained by the finite element method based numerical simulation results. At the second step, I have measured the surface potential of living cell membrane at selected locations. Very recently, I have obtained results to show that we can map the extracellular membrane potential distribution of the complicated living cell membrane with sub-micron spatial resolution.This new imaging technique can help biologist to explore the extracellular potential distribution of varieties of cells quantitatively.These studies will have impacts on several biomedical applications such as regenerative repair and cancer treatment.
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41

Yukna, Jennifer. "Computational and experimental investigations of the structural properties, electronic properties, and applications of silver, gold, mercury selenide, silver sulfide, and nickel sulfide nanoparticles /." Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1482010021&sid=2&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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Thesis (Ph. D.)--Southern Illinois University Carbondale, 2007.
"Department of Chemistry and Biochemistry." Keywords: Electronic properties, Silver, Gold, Mercury selenide, Silver sulfide, Nickel sulfide, Nanoparticles. Includes bibliographical references (p. 170-180). Also available online.
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42

Bouclé, Johann. "Elaboration et étude des propriétés électro-optiques de matériaux hybrides à base de nanocristaux de carbure de silicium." Phd thesis, Université du Maine, 2004. http://tel.archives-ouvertes.fr/tel-00007825.

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Ce travail concerne l'élaboration de matériaux hybrides à base de matrices hôtes polymères et de nanocristaux de carbure de silicium (SiC) et l'étude de leurs propriétés électro-optiques. Dans ce contexte, différents échantillons de SiC ont été synthétisés par pyrolyse laser d'un mélange gazeux (silane, acétylène) et deux nanopoudres représentatives ont principalement été exploitées. Les études spectroscopiques ont révélé des états de surface différents, conditionnant les interfaces au sein du composite final. Le dépôt de films minces hybrides a été effectué à partir de suspensions précurseurs homogènes de qualité contrôlée, suivi de traitements thermiques et électriques appropriés. Enfin, au travers de l'étude de différents paramètres (concentration en nanocristallites SiC, état de surface, nature du polymère, etc.), la mesure des coefficients électro-optiques effectifs (Pockels et Kerr), par l'utilisation d'un montage adapté à la géométrie des échantillons, a révélé le rôle prépondérant de l'interface SiC-polymère sur la réponse des composites. Avec des coefficients électro-optiques effectifs de l'ordre de 5 à 7 pm/V, ces composites présentent des performances comparables à celle des cristaux électro-optiques standards et permettent d'envisager une application du système hybride SiC/polymère pour l'optoélectronique intégrée.
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43

Gollamandala, Deepika Rao. "Brownian dynamic simulations of nanoparticle dispersions in polymer solutions a thesis presented to the faculty of the Graduate School, Tennessee Technological University /." Click to access online, 2009. http://proquest.umi.com/pqdweb?index=13&did=1913184241&SrchMode=1&sid=1&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1265056184&clientId=28564.

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44

Vicario, Gomez Iban. "Influence des nano-particules d’alumine (Al2O3) et de di-borure de titane (TiB2) sur la microstructure et les propriétés de l’alliage Al-Si9-Cu3-Fe1 pour des applications de fonderie à haute pression." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14420/document.

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Ce travail est dédié á l´étude de l´influence de nano-particules de alumina (Al2O3) et de di-borure de titane (TiB2) sur la solidification, la microstructure et les propriétés thermiques et mécaniques de l´alliage d´aluminium renforcés, Al-Si9Cu3Fe1. Les matériaux ont été obtenus par un procédé de fonderie à haute pression en coulant les alliages dans les mêmes conditions que les alliages non renforcés correspondants.On a constaté que les particules de Al2O3 et de TiB2 ont une influence directe sur les caractéristiques de l´alliage telles que la microstructure, la précipitation des phases pendant la solidification et les propriétés mécaniques et électriques. On a ainsi montré que les particules de Al2O3 et de TiB2 peuvent être utilisées pour ajuster les caractéristiques des alliages et obtenir des propriétés spécifiques pour des applications dans les secteurs de matériaux légers
The work has been focused on the study of the influence of TiB2 and Al2O3 nano-particles (up to 1 wt. %) on the properties and physical features of an aluminium casting alloy, Al-Si9Cu3Fe1.Samples have been obtained through the High Pressure Die Casting (HPDC) process and compared with unreinforced samples obtained at the same conditions. It has been observed that the Al2O3 and TiB2 particles have a direct influence on several features of the alloy such as the microstructure and precipitating phases as well as in the improvement of the soundness and mechanical and electrical properties. Al2O3 and TiB2 particles can be used to tailor the properties of the alloy and to match the specifications of light weight applications
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45

"Reinforcement of syntactic foam with SiC nanoparticles." Thesis, Florida Atlantic University, 2009. http://purl.flvc.org/FAU/359923.

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In this investigation, polymer precursor of syntactic foam has been reinforced with SiC nanoparticles to enhance mechanical and fracture properties. Derakane 8084 vinyl ester resin was first dispersed with 1.0 wt% of SiC particles using a sonic cavitation technique. In the next step, 30.0 wt% of microspheres (3M hollow glass borosilicate, S-series) were mechanically mixed with the nanophased vinyl ester resin, and cast into rectangular molds. A small amount of styrene was used as dilutant to facilitate mixing of microspheres. The size of microspheres and SiC nanoparticles were 20-30 um and 30-50 nm, respectively. Tension, compression, and flexure tests were conducted following ASTM standards and a consistent improvement in strength and modulus within 20-35% range was observed. Fracture toughness parameters such as KIC and GIC were also determined using ASTM E-399. An improvement of about 11-15% was observed. Samples were also subjected to various environmental conditions and degradation in material properties is reported
by Debdutta Das
Thesis (M.S.C.S.)--Florida Atlantic University, 2009
Includes bibliography
Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web
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46

Han, Yi-Fan, and 韓依帆. "Preparation and application in electromagnetic wave absorption of SiC nanoparticles embedded in Polyacrylonitrile through electrosppinning." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/uhw4m5.

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碩士
明新科技大學
化學工程與材料科技系碩士班
105
In this study, silicon carbide/polyacrylonitrile (SiC/PAN) composite nanofibers material for absorbing electromagnetic waves were prepared by electrospinning. In this experiment, polyacrylonitrile (PAN) was mixed with dimethylformamide (N, N-dimethyformamide, DMF) solution by changing collecting plate distance four process parameters: PAN concentration, collecting plate voltage, feeding rate. The effects of these parameters on the morphology and diameter of PAN nanofibers were discussed. Synthesis of SiC/Carbon composite nanofiber fraction, respectively, adding different concentrations of SiC nanoparticles into the precursor solution, and then the above PAN conditions for electrospinning. At the same time, the electromagnetic wave absorption of SiC/Carbon composite nanofibers with different weight percentages was studied. In this study, the fiber morphology and diameter were observed by scanning electron microscopy. The X-ray diffraction apparatus was used to identify the SiC/Carbon phase. The weight change of the sample was observed by thermogravimetric analysis and the microstructure of the penetrating electron microscope Identification and four-point probe electrical analysis, and then use the vector network analyzer, the radar wave band (3-18 GHz) of the electromagnetic properties of the study. The results showed that PAN nanofibers could obtain more uniform diameter PAN nanofibers at a concentration of 10 wt%, a voltage of 20 kV, a feeding rate of 0.025 ml/min and a collection distance of 15 cm. The surface roughness increases with the addition of 15 wt% SiC nanoparticles, which means that the SiC nanoparticles begin to agglomerate, but there is no obvious aggregation of silicon carbide nanoparticles compared with 20 wt%. At room temperature measurement, the sample number (A2) increases with the thickness of the maximum reflection loss increases, and will move to low frequency, the thickness of 8 mm, in the 13.79-17.54 GHz frequency range, the reflection loss is less than -10 dB of the bandwidth of 3.75 GHz, the maximum reflection loss at the radar frequency of 15.29 GHz is -38.19 dB.
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47

Chen, Jian-Jr, and 陳建志. "STUDIES ON THE IONIC CONDUCTIVITY OF PEO/LiClO4 SOLID POLYMER ELECTROLYTE BLENDED WITH NANOPARTICLES (TiO2, SiO2, CdS, SiC) AND TEOS." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/12233586924224516752.

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Abstract:
碩士
大同大學
化學工程研究所
91
It has been found that the nano-sized materials are very helpful in the solid polymer electrolyte and therefore it has become an important research field. In this study, the solid polymer electrolyte have been prepared based on poly(ethylene oxide) (PEO) blended with different weight percentages of alkali metal salt (LiClO4). The X—ray diffraction and DSC studies reveal the crystallization of PEO, which is reduced with increasing the content of LiClO4. From the AC impedance measurements, the ionic conductivity of the PEO/LiClO4 SPE systems increases initially with decreasing [EO]/[Li+] ratio and reaches maximum value (7.13 × 10 — 6 S/cm) at the [EO]/[Li+] ratio of 10, but decreases as the [EO]/[Li+] ratio is further decreased. It can be found that SPE system blended with nanoparticles ((TiO2, SiO2, and CdS), and tetraethoxysilane (TEOS)) can enhance the ionic conductivity, except for SiC. The highest ionic conductivity of P(EO)8LiClO4 blended with 3 wt% of TEOS can reach 7.83 × 10 — 4 S/cm at room temperature, which is close to those of lithium liquid electrolyte lithium batteries (10 — 2 ~ 10 — 3 S/cm) used extensively at present. The ionic conductivities of P(EO)8LiClO4 SPE system blended with 3 wt% of SiO2, TiO2, and CdS is 2.9 × 10 — 4, 3.9 × 10 — 4, and 4.83 × 10 — 4 S/cm, respectively. In other words , the order of ionic conductivity for SPE blended with 3 wt% of nanoparticles is TEOS ＞ CdS ＞ TiO2 ＞ SiO2 ＞ SiC. The result can be confirmed by SEM micrographs. It can be found that SPE system blended with nanoparticles (TiO2, SiO2, and CdS) can improve the tensile strength stability of SPE film.
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48

Lu, Yan Jiun, and 盧晏君. "Electrical property of SiC nanoparticle in D.I. water." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/76511592119121961613.

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碩士
國立臺北科技大學
製造科技研究所
90
The electrical properties of SiC nanoparticles are investigated in this research. Different acid-base solutions and voltages are our recipes which can observe SiC nanoparticles with electrified property and precipitate phenomenon. Additionally, the transparent thin film is also studied found in the anode with an experiment of pH2 solution. From our investigation, if found that SiC nanoparticles in D.I. water can resist oxidation and have an excellent chemical stability. NaOH and H2SO4 in nanoparticle solution are mixed to generate pH7, pH10 and pH2 solution respectively. At different voltages, Cu electrode inserts into solution to observe the status of particle around electrode and to monitor phenomenon for SiC precipitates solution by particle size analyzer. Furthermore, a transmission electron microscope is need to observe the status of powder in the different solutions and a XRD for analysis of the compositions about SiC particle. In the acid-base solution, three-electrode makes the curve of anodic polarization for SiC particle that finds the potential of positive pole reduction to get electrical property of SiC particle fully. In the other way, after pH2 reaction, a transparent film on the Cu electrode was found. The transparent film is observed in a microhardness test. A field emission scanning electron microscope and an energy dispersive spectrometers analyze the substance of film’s surface to gain compositions and characters. The charge of SiC nanoparticles in D.I. water is negative. The collect scale is larger when the voltage is higher. The pH10 solution make the charge of the surface of SiC nanoparticles more strong. In the other way, a transparent film isn’t SiC. the time of reaction is longer and then the thickness of the transparent film is much more; when the voltage is higher and the transparent film is denser.
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49

Lee, Yuhan, and 李育翰. "Nanoparticle fractionation of silica sol by the HPLC-SEC." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/31694254854844875083.

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Abstract:
碩士
明志科技大學
化學工程研究所
100
In this study, size exclusion liquid chromatography (HPLC SEC) fractionates of nanoparticles of silica sol . Discuss the preparation of silica sol dispersion diameter grading efficiency and operating conditions for surface modification and particle size fractionation. In this study, silica sol of nanoparticles classification experiments is divided into three types: self-made silica sol, silica sol of silica nano powder to deploy, as well as commercially available.Regulation of nano particle size of the Stöber method made sol by aging time the availability of two particle size distribution of silica sol. Commercially available silica nano powder homogenizer, add three modifier: Sodium n-dodecyl sulfate (SDS), Triton X-100, Acetylacetone (HACAC).Among them, only SDS on particle dispersion enhance the effect of surface modification effect of the three to avoid the silica sol particles and the column packing adsorption. In this experiment, a commercially available silica sol, self made silica sol and the effect of commercially available nano gold sol, to investigate the particle size fractionation experiments and nano particle size classification. The results showed that poor grading effect of the commercially available silica sol and a commercially available nano gold colloids (commercially available silica sol Rs = 0.23, a commercially available nano gold colloids Rs = 0.49), while the homemade silica sol the difference of the two kinds of particle size distribution and better particle size fractionation effects (self made silica sol Rs = 0.55).
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50

Coelho, David José Pereira. "Fabrication of Gd5 (Si1-xGex )4 nanoparticles by femto and nanosecond pulsed laser ablation in liquids." Master's thesis, 2018. https://hdl.handle.net/10216/118851.

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