Global ETD Search

131	Atomic Layer Deposition of Boron Oxide and Boron Nitride for Ultrashallow Doping and Capping Applications Pilli, Aparna 12 1900 (has links) The deposition of boron oxide (B₂O₃) films on silicon substrates is of significant interest in microelectronics for ultrashallow doping applications. However, thickness control and conformality of such films has been an issue in high aspect ratio 3D structures which have long replaced traditional planar transistor architectures. B₂O₃ films are also unstable in atmosphere, requiring a suitable capping barrier for passivation. The growth of continuous, stoichiometric B₂O₃ and boron nitride (BN) films has been demonstrated in this dissertation using Atomic Layer Deposition (ALD) and enhanced ALD methods for doping and capping applications. Low temperature ALD of B₂O₃ was achieved using BCl₃/H₂O precursors at 300 K. In situ x-ray photoelectron spectroscopy (XPS) was used to assess the purity and stoichiometry of deposited films with a high reported growth rate of ~2.5 Å/cycle. Free-radical assisted ALD of B₂O₃ was also demonstrated using non-corrosive trimethyl borate (TMB) precursor, in conjunction with mixed O₂/O-radical effluent, at 300 K. The influence of O₂/O flux on TMB-saturated Si surface was investigated using in situ XPS, residual gas analysis mass spectrometer (RGA-MS) and ab initio molecular dynamics simulations (AIMD). Both low and high flux regimes were studied in order to understand the trade-off between ligand removal and B₂O₃ growth rate. Optimization of precursor flux was discovered to be imperative in plasma and radical-assisted ALD processes. BN was investigated as a novel capping barrier for B₂O₃ and B-Si-oxide films. A BN capping layer, deposited using BCl₃/NH₃ ALD at 600 K, demonstrated excellent stoichiometry and consistent growth rate (1.4 Å/cycle) on both films. Approximately 13 Å of BN was sufficient to protect ~13 Å of B₂O₃ and ~5 Å of B-Si-oxide from atmospheric moisture and prevent volatile boric acid formation. BN/B₂O₃/Si heterostructures are also stable at high temperatures (>1000 K) commonly used for dopant drive-in and activation. BN shows great promise in preventing upward boron diffusion which causes a loss in the dopant dose concentration in Si. The capping effects of BN were extended to electrochemical battery applications. ALD of BN was achieved on solid Li-garnet electrolytes using halide-free tris(dimethylamino)borane precursor, in conjunction with NH₃ at 723 K. Approximately 3 nm of BN cap successfully inhibited Li₂CO₃ formation, which is detrimental to Li-based electrolytes. BN capped Li-garnets demonstrated ambient stability for at least 2 months of storage in air as determined by XPS. BN also played a crucial role in stabilizing Li anode/electrolyte interface, which drastically reduced interfacial resistance to 18 Ω.cm², improved critical current density and demonstrated excellent capacitance retention of 98% over 100 cycles. This work established that ALD is key to achieving conformal growth of BN as a requirement for Li dendrite suppression, which in turn influences battery life and performance. Atomic Layer Deposition Free radical assisted ALD Room temperature ALD Boron Oxide Boron Nitride Silicon Doping Passivation Barrier Capping Barrier Lithium Garnet All-Solid-State Battery X-ray Photoelectron Spectroscopy Electrochemistry
132	PCB i Oxundasjön och Rosersbergsviken : Prediktiv modellering av återhämtningsscenarier Hållén, Joakim January 2016 (has links) A regional survey of environmentally harmful substances in fish in autumn 2013 revealed elevated levels of polychlorinated biphenyls (PCBs) in perch from Lake Oxundasjön, north of Upplands Väsby in Stockholm County. Follow-up studies have shown that the quantity of PCBs contained in the lake is unique of its kind in Sweden, and that the area of influence also includes downstream Rosersbergsviken, a bay of Lake Mälaren. The elevated concentrations in fish exceed today's market limits and environmental quality standards for PCBs, as of this, responsible authorities discourage from consumption of fish from Lake Oxundasjön and Rosersbergsviken. The aim has been to use statistical analyses and mass-balance modelling to study the current state of the lake system and how it may evolve in the future under different circumstances. There is a statistically significant correlation between PCB levels in sediment and perch from 21 different sites in the Stockholm-Mälaren region, including Lake Oxundasjön and Rosersbergsviken, this was demonstrated with a linear regression model. With the multivariate analysis method principal component analysis (PCA), it was illustrated how the contaminant levels in fish from Lake Oxundasjön and Rosersbergsviken differed on contaminant levels in fish from other sites. The difference mainly concerned the size and composition of PCBs. Mass-balance modelling of quantities and flows of PCBs in Lake Oxundasjön and Rosersbergsviken was made in the simulation program STELLA®. The modelling indicated that the system currently serves as a secondary distribution source of PCBs to the environment. The recovery of PCB levels is slow in the system, it will take more than 25 years for concentrations in fish to reach today’s market limits and environmental quality standards for PCBs. The model was used to evaluate three different treatment methods for Lake Oxundasjön: dredging, capping and activated carbon treatment. Simulations of these treatments led to a substantial improvement of the PCB situation in Lake Oxundasjön. Moreover, they also had a positive impact on the recovery process in the downstream Rosersbergsviken. Future climate changes, with warmer temperatures and higher run off, led to a slightly faster recovery progress of PCBs in the system. PCBs aquatic ecosystems contaminated sediments fish dredging capping activated carbon PCA mass-balance modelling SIMCA STELLA PCB akvatiska ekosystem förorenade sediment fisk muddring täckning aktivt kol PCA massbalansmodell SIMCA STELLA Engineering and Technology Teknik och teknologier
133	Les matériaux d'obturation et de coiffage pulpaire des dents lactéales Shayegan, Amir 17 September 2012 (has links) Les soins pulpaires en denture lactéale sont les soins fréquemment réalisés en odontologie pédiatrique et la réaction pulpaire ainsi que les mécanismes de réparation tissulaire lors d’un traumatisme ne sont pas très bien connus ou investigués. En se référant à la littérature dentaire, on constate que les recherches sont souvent focalisées sur la denture définitive.<p>Objectifs<p>1) Etudier l’influence du traitement avec divers matériaux sur la formation dentinaire, la structure tissulaire et le degré d’inflammation.<p>2) Acquérir des connaissances sur l’interaction à l’interface matériau/tissu.<p>3) Etudier le rôle de la voie de signalisation Notch (1 et 2) dans le processus de remaniement et réparation du tissu pulpaire en cas de traumatisme.<p>Matériels et méthodes<p>Deux types de soins pulpaires, la pulpotomie et le coiffage direct, sont réalisés sur les dents lactéales porcines et les résultats sont étudiés après 3 périodes :7 jours, 21-28 jours et 90 jours.<p>La pulpotomie :8 matériaux, 10 dents par matériau, 2 matériaux par cochon et par période pour un total de 240 dents.<p>Le coiffage direct :10 matériaux, 10 dents par matériau, 2 matériaux par cochon et par période pour un total de 300 dents.<p>Par la suite, différentes techniques ont été utilisées :<p>1. La microscopie optique :étude des coupes histologiques après coloration.<p>2. La microscopie électronique à transmission :observer les caractéristiques morphologiques du tissu pulpaire et analyser les structures cellulaires en détail. L’objectif principal de cette recherche était centré sur les biomatériaux pour la période de 21-28 jours afin d’examiner l’interaction entre le biomatériau et le complexe dentino-pulpaire après leur placement.<p>12<p>3. La voie de signalisation Notch (1 et 2): investiguer l’intervention éventuelle de cette voie dans le processus de régénération tissulaire par différenciation des cellules pour les deux périodes de 7 et 21-28 jours pour tous les matériaux utilisés.<p>Résultats<p>A. Microscopie optique :<p>1. La pulpotomie :les biomatériaux provoquent moins d’infiltrat de cellules inflammatoires au niveau du tissu pulpaire et favorisent la déposition dentinaire.<p>2. Le coiffage direct :on obtient les mêmes résultats que dans le cadre de la pulpotomie.<p>B. Microscopie électronique en transmission :<p>1. L’induction du tissu calcifié ou la formation de néo-dentine s’est seulement produite au niveau du site de l’exposition après le placement des biomatériaux dans les 2 types du traitement (pulpotomie & coiffage direct). En revanche aucune formation du tissu calcifié n’a été observée dans le parenchyme pulpaire à distance du site de l’exposition.<p>2. Cet examen montre que les cellules en contact des biomatériaux ou même à proximité de ces derniers présentent un réticulum endoplasmique élargi parallèle à la longueur de la cellule. Des mitochondries, plusieurs appareils de Golgi et des éléments denses sont observés dans le cytoplasme cellulaire.<p>3. Cet examen a également montré que le MTA et le WPC, considérés par la littérature dentaire comme non-résorbables, sont phagocytés par les cellules histiocytaires.<p>C. Voie de signalisation de Notch :<p>Nos recherches n’ont pas montré de marquage concluant pour aucun de matériaux sauf dans le cadre de coiffage direct pour les dents traitées au MTA et Ca(OH)2 pour la période de 7 jours. Par contre, aucun marquage n’est observé après 21-28 jours. / Doctorat en Sciences dentaires / info:eu-repo/semantics/nonPublished Médecine pathologie humaine Dental pulp -- Diseases Dental pulp -- Diseases -- Treatment Dental pulp -- Capping Deciduous teeth Dental materials Fillings (Dentistry) Pulpe dentaire -- Maladies Pulpe dentaire -- Maladies -- Traitement Pulpe dentaire -- Coiffage Dents de lait Matériaux dentaires Obturations (Dentisterie) voie de signalisation Notch traitement pulpaire Dent lactéale
134	Charakteristické vlastnosti směsných recyklátů pro spodní stavbu pozemních komunikací / Characteristics of mixed building recyclates for subgrade og roads Junek, Lumír Unknown Date (has links) The work deals with the use of mixed construction recycled material for earth bodies of roads. The theoretical part describes the production, usability and economic evaluation of recycled building materials against common natural materials. It then describes the necessary laboratory tests that examine its properties for the use of these materials in roads. In the last chapter, the work deals with foreign experience with the use of mixed construction recyclates for transport construction. The practical part examines the properties of the given recyclates for their use in the core using tests of soil freezing rate, California bearing ratio and immediate bearing index.
135	Směsný recyklát do podloží vozovek pozemních komunikací / Waste building material to subgrade pavement Masař, Daniel Unknown Date (has links) The theoretical part of the diploma thesis searches the production of Construction and demolition waste and their subsequent transformation into the final recyclate and its possible use in roads. Attention is focused on the use of mixed recycled material into subgrade of the pavement and the characteristics of tests that must be performed before its used to the road. The next chapters pai attention to the problematic properties of recyclates, foreign experience with the use of mixed recyclate in Construction and the possibilities of its development. The practical part verifies the suitability of mixed recycled material into subgrade of the pavement using laboratory tests. The tests are performer on individual mixtures of mixed recycled material with cement, blast furnace slag or cement dust in various percentages. The results are then compared and it is evaluated which mixtures show the best properties. Part of the practical part is also the economic evaluation of these mixtures against commonly used materials.
136	Nanolithography on thin films using heated atomic force microscope cantilevers Saxena, Shubham 01 November 2006 (has links) Nanotechnology is expected to play a major role in many technology areas including electronics, materials, and defense. One of the most popular tools for nanoscale surface analysis is the atomic force microscope (AFM). AFM can be used for surface manipulation along with surface imaging. The primary motivation for this research is to demonstrate AFM-based lithography on thin films using cantilevers with integrated heaters. These thermal cantilevers can control the temperature at the end of the tip, and hence they can be used for local in-situ thermal analysis. This research directly addresses applications like nanoscale electrical circuit fabrication/repair and thermal analysis of thin-films. In this study, an investigation was performed on two thin-film materials. One of them is co-polycarbonate, a variant of a polymer named polycarbonate, and the other is an energetic material called pentaerythritol tetranitrate (PETN). Experimental methods involved in the lithography process are discussed, and the results of lithographic experiments performed on co-polycarbonate and PETN are reported. Effects of dominant parameters during lithography experiments like time, temperature, and force are investigated. Results of simulation of the interface temperature between thermal cantilever tip and thin film surface, at the beginning of the lithography process, are also reported. Characterization Deflection Setpoint Grain rearrangement Array Precise positioning Metrology Explosion Explosives Data storage Material Image processing Slow scan disabled Temperature Tip Local In-situ Nanoscale Electrical circuit fabrication Repair Co-polycarbonate Polymers Polycarbonates Energetic materials PETN Simulation Interface Nano-manufacturing Experiment Calibration Raman Frequency Deflagration Decomposition Detonation Build up Pile-up End capped End capping Cross linked Cross-linked Conductivity Microscale MEMS Microcantilever NEMS DPN tDPN Silicon Glass Peak InVOLS Manipulation AFM Atomic force microscope Defense Nanoscale Surface Stiffness Force Scan size Thermal cantilevers Imaging Lithography Nanolithography Thin films Cantilevers Heaters Technology Nanotechnology Scan velocity Scan rate Bake Anneal Pentaerythritol tetranitrate Thin films Thermal properties Atomic force microscopy Microlithography Nanotechnology Surfaces (Technology) Analysis

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