Dissertations / Theses on the topic 'Micro deposits'
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1
Young, Thomas. "Dépôts micro structurés pour la réalisation de capteurs d’activité hydrolytique." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILN062.
Abstract:
La phytase, une enzyme capable d'hydrolyser séquentiellement l'acide phytique en formant des inositols moins phosphorylés et du phosphate, est de plus en plus souvent ajoutée aux régimes alimentaires des animaux afin d'optimiser l'absorption du phosphore par les animaux monogastriques et de réduire sa présence dans les fèces et les sols. À cet égard, la possibilité de mesurer son activité est évidemment d'un intérêt primordial. Cependant, à ce jour, il existe très peu de méthodes permettant de mesurer facilement l'activité de la phytase dans l'industrie. Les principales raisons sont que les techniques actuelles sont chronophages, ne sont pas adaptées aux échantillons d'aliments complexes et utilisent des réactifs dangereux.Dans ce projet de thèse, nous avons proposé de développer un capteur enzymatique innovant dédié à la détection de l'activité de la phytase dans des échantillons complexes en utilisant une méthode de détection directe grâce à la technologie de Zymoptiq. L'acide phytique, substrat de la phytase, possède de nombreuses charges négatives qui peuvent interagir avec des polymères chargés positivement comme le chitosan pour former des complexes. Ce phénomène est bien connu et documenté dans la littérature et constitue la pierre angulaire de notre capteur. Notre capteur est basé sur la dégradation de micro dépôts basés sur une structure en réseau de chaînes de chitosan insensibles à l'enzyme et réticulées avec de l'acide phytique lorsqu'ils sont incubés en présence d'activité phytase (FTU/mL).Cependant, pour assurer la stabilité du micro dépôt, une étude systématique a été menée pour mieux contrôler et comprendre tous les phénomènes sous-jacents liés à son assemblage. Cela a aussi permis d'améliorer la sensibilité du capteur développé. Grâce à des versions intermédiaires, nous avons démontré la capacité de notre méthode à mesurer l'activité d'un échantillon de phytase pure de 100 FTU/mL et d'un échantillon d'aliment complexe simulé avec des activités aussi faibles que 20 mFTU/mL. Enfin, après avoir caractérisé le mécanisme d'hydrolyse de l'acide phytique complexé avec le chitosan par la phytase, cette étude nous a permis de proposer une méthode de mesure innovante, sûre et rapidePhytase, an enzyme capable of sequential hydrolysis of phytic acid to lower phosphorylated inositols and phosphate, has been increasingly added to animal diets to optimize phosphorus uptake by monogastric animals and to reduce its presence in faeces and soils. In this respect, the ability to measure its activity is obviously of primary interest. However, to date there are very few methods available to easily measure phytase activity in industry. The main reasons are that current techniques are time consuming, not suitable for complex feed samples and use hazardous reagents.In this thesis project, we proposed to develop an innovative enzymatic sensor dedicated to the detection of phytase activities in complex samples using a label-free approach thanks to Zymoptiq's technology. Phytic acid, the substrate of phytase, possesses numerous negative charges that can interact with positively charged polymers such as chitosan to form complexes. This phenomenon is well known and documented in the literature and is the cornerstone of our sensor. Our sensor is based on the degradation of micro deposits-based on a network structure of enzyme-insensitive chitosan chains cross-linked with phytic acid- when incubated in the presence of phytase activity (FTU/mL).However, to ensure the stability of the micro deposit, a systematic study was carried out to better control and understand all the underlying phenomena related to the complexes assembly. This also allows us to tailor our sensor's sensitivity. Through intermediate versions, we have demonstrated the ability to measure the activity of both a pure phytase sample of 100 FTU/mL and a simulated complex feed sample with activities as low as 20 mFTU/mL. Finally, after characterizing the hydrolysis mechanism of phytic acid complexed with chitosan by phytase, this study has enabled us to propose an innovative, safe and time-saving method of measurement
2
Barron, Lance W. "High-reflectance, sputter-deposited aluminum alloy thin films for micro-electro-mechanical systems /." Online version of thesis, 2005. http://hdl.handle.net/1850/5195.
3
Perry, Richard. "Towards environmentally friendly electrodeposition : using citrate based electrolytes to deposit nickel and nickel-iron." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/16184.
Abstract:
The production of magnetic materials is of great interest for use in the micro-fabrication industry. In particular, Permalloy (Ni80Fe20) is used in the production of micro-electromechanical systems (MEMS) due to its favourable magnetic properties (high relative permeability, low coercivity and high magnetic saturation). This leads to applications in devices such as inductors, transformers and micro-actuators. The electrodeposition of NiFe is also of fundamental electrochemical interest, as there is anomalous thermodynamic behaviour, with the less noble (iron) metal depositing preferentially to the more noble (nickel) metal. To enable consistent alloy deposition nickel and nickel-iron baths are currently almost exclusively based on boric acid. Boric acid has an important role in the deposition of NiFe films but its role(s) in the electro-deposition mechanism is (are) not wholly understood. Recently (2011) boric acid has been identified as a “substance of very high concern” based on the criteria established by EU chemical regulation, REACH. In anticipation of increased regulation an alternative was sought to provide a benign alternative to boric acid in the NiFe plating bath suitable for use in micro-fabrication. Initial work was performed to benchmark the performance of existing boric acid based electro-deposition baths. Cyclic voltammetry was performed, which demonstrated the deposition of nickel and nickel-iron from boric acid baths. Coulombic efficiencies up to 93 % were measured for the deposition of nickel using the electrochemical quartz crystal microbalance (EQCM) on platinum electrodes. For nickel-iron deposition control of the film composition was demonstrated on copper electrodes through varying the iron (II) concentration, current density and temperature. A citrate bath for the deposition of nickel-iron was then developed and characterised. Cyclic voltammetry was performed in these citrate baths demonstrating the deposition of nickel and nickel-iron. Optimal conditions for depositing Ni80Fe20 were demonstrated to be an elevated temperature (60 °C) with a current density of 20 mA cm-2 and a pH of 3. Using the EQCM the efficiency for nickel deposition was measured to be > 80 %. The effects of sodium saccharin and sodium dodecyl sulfate as additives were investigated; these were shown to influence morphology but not the coulombic efficiency. Decreasing the pH was shown to lower the efficiency of nickel deposition from the citrate bath. Comparisons of key properties were made between NiFe films deposited from a boric acid bath and the citrate bath developed in this work. Test structures were used to compare the strain in the films; no significant difference was found. For 2.2 μm thick Ni80Fe20 films the sheet resistance was measured using Greek cross structures as 0.078 ± 0.004 Ω/square for films deposited from the boric acid bath and 0.090 ± 0.006 Ω/square from the citrate bath. The magnetic saturation, Ms, was measured as 895 ± 66 emu cm-3 for deposits from the boric acid bath and 923 ± 111 emu cm-3 from the citrate bath. These again show no significant difference in these values within experimental error. Coercivities for these films were measured to be between 20 and 120 A m-1. In combination, this work demonstrates the development and characterisation of a new citrate based electrodeposition bath for nickel and nickel-iron. Similar chemical, electrical, mechanical and magnetic properties were found from films deposited from both baths, thus demonstrating the suitability of the citrate bath for the deposition of nickel-iron films in microfabrication.
4
Jaber, Wassim. "Phonon heat conduction probed by means of an electro-thermal method involving deposited micro and nanowires." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI109/document.
Abstract:
The context of this PhD is the reduction of sizes involved in material development and the confinement of heat in modern devices, which are known to lead to the apparition of hot spots. The goal is to investigate heat conduction from micro- to nanoscale wide Joule-heated wires standing on flat layered materials. A particular focus is given to the analysis of phonon heat dissipation when departing from the well-known Fourier diffusive conduction and entering the ballistic regime. The manuscript starts with a summary of the main observed effects on the effective thermal conductivity in nanoscale materials, especially in light of the values of thermallyaveraged phonon mean free paths and the associated Knudsen number. Then the advantages and drawbacks of various measurement techniques are discussed. The analysis of the experimental configuration requires 2D analytical and 3D finite-element method based numerical studies of diffusive heat conduction from a finite source into a medium. Limitations of the 3! method due to wire length, substrate geometry and thin oxide layers are highlighted. The electro-thermal setup developed and the procedure used to deposit the devices on top of the samples are then detailed. A set of well-known materials with mean free path ranging from few nanometers to hundreds of nanometers is characterized with microwires. The thermal conduction properties of multilayer materials are investigated. Heat dissipation from finite sources on top of silicon substrates is then measured as a function of temperature. The mean free path is known to become large when temperature decreases. As a result, this configuration provides clues for understanding heat conduction from ballistic sources. The observed behavior is very different from the one predicted by Fourier’s law and shows a strong reduction of the dissipation. It is found that the results are comparable to earlier measurements involving ridges. They are analyzed with various levels of approximations of predictions using the Boltzmann transport equation. The results obtained may be useful in many fields, in particular for electronics and thermoelectric designsLe contexte de ce doctorat est la réduction des tailles impliquées dans le développement des matériaux et le confinement de la chaleur dans les dispositifs modernes, qui sont connus pour conduire à l'apparition de points chauds. L'objectif est d'étudier la conduction de la chaleur à partir de fils chauffés par Joule à l'échelle nanométrique et à l'échelle nanométrique, reposant sur des matériaux à couches planes. Une attention particulière est accordée à l'analyse de la dissipation thermique des phonons en partant de la conduction de Fourier bien connue et en entrant dans le régime balistique. Le manuscrit commence par un résumé des principaux effets observés sur la conductivité thermique effective dans les matériaux à l'échelle nanométrique, en particulier à la lumière des valeurs des voies libres moyennes des phonons et du nombre de Knudsen associé. Ensuite, les avantages et les inconvénients des différentes techniques de mesure sont discutés. L'analyse de la configuration expérimentale nécessite des études numériques 2D basées sur la méthode des éléments finis et des éléments finis de la conduction de chaleur par diffusion à partir d'une source finie dans un milieu. Limitations du 3! méthode en raison de la longueur du fil, de la géométrie du substrat et des couches minces d'oxyde sont mises en évidence. La configuration électro-thermique développée et la procédure utilisée pour déposer les dispositifs sur les échantillons sont ensuite détaillées. Un ensemble de matériaux bien connus avec un chemin libre moyen allant de quelques nanomètres à des centaines de nanomètres est caractérisé par des microfils. Les propriétés de conduction thermique des matériaux multicouches sont étudiées. La dissipation thermique des sources finies sur les substrats de silicium est ensuite mesurée en fonction de la température. Le libre parcours moyen est connu pour devenir important lorsque la température diminue. En conséquence, cette configuration fournit des indices pour comprendre la conduction de la chaleur à partir de sources balistiques. Le comportement observé est très différent de celui prédit par la loi de Fourier et montre une forte réduction de la dissipation. On trouve que les résultats sont comparables à des mesures antérieures impliquant des crêtes. Ils sont analysés avec différents niveaux d'approximations de prédictions en utilisant l'équation de transport de Boltzmann. Les résultats obtenus peuvent être utiles dans de nombreux domaines, en particulier pour les conceptions électroniques et thermoélectriques
5
Lawson, Thomas Ryan. "Micro-Raman spectroscopy and dry turning evaluations of nanostructured diamond films deposited on tungsten-carbide lathe inserts." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008m/lawson.pdf.
6
Tripp, Marie K. "Atomic layer deposited thin films for micro- and nano-electromechanical systems with applications in short-wavelength adaptive optics." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/dissertations/fullcit/3165821.
7
Steinhauer, Tim [Verfasser]. "On the Micro- and Ultrafiltration of Dairy Fluids - Molecular Mechanisms of Membrane Fouling and Elucidation of Deposit Layer Structures / Tim Steinhauer." München : Verlag Dr. Hut, 2016. http://d-nb.info/1113335769/34.
8
Barbosa, Leo. "EXAMINATION OF MICRO-SCALE SULFIDE DISTRIBUTION FOR THE GOLD MINERALIZATION IN THE LAPPBERGET DEPOSIT, GARPENBERG MINE, SWEDEN: TOWARDS A GEOMETALLURGICAL APPROACH." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-87022.
Abstract:
Ore characterization studies are of great importance to the mining industry, especially when dealing with precious metals by-products. It is a way towards increasing mining efficiency. The Swedish Boliden’s Zn–Pb–Ag–(Cu–Au) Lappberget Deposit is the main ore body at the Garpenberg Mine producing concentrates of zinc, lead, copper, and a gravity concentrate of silver and gold, which accounts for a significant revenue for the mine. Garpenberg Mine is an ancient and traditional mining site in Sweden, nonetheless the Lappberget deposit is a relatively recent discovery and there are still on-going studies on this ore body. More recently detailed ore investigations have been carried out on the sulfides and silver mineralization in different geological domains within the Lappberget deposit. In this context, the present work is focused on investigating the gold mineralization of the deposit, aiming to study the occurrence and distribution of gold minerals, characterize the gold in the ore and how its characteristics affect gold recoveries during its processing. To achieve these goals, different investigative methods were applied on drill core samples of the footwall disseminated to semi-massive mineralization (FWD), and on samples from the gravity concentrator at Boliden’s processing plant. The techniques applied were optical microscopy, scanning electron microscopy, energy dispersive x-ray spectrometry, electron probe microanalysis, laser ablation inductively couple plasma mass spectrometry, and bulk chemical analysis. The main findings pointed electrum as the main gold mineral, occurring with a strong sulfide association, in a variety of textures and grain sizes. The study also identified the occurrence of Au-Bi alloy, not previously described in literature of the Garpenberg region. The potential of invisible gold in the sulfide carriers was also a subject of investigation, as well as the evaluation of the characteristics of the samples from the gravity concentrator.
9
Barbakadze, Nato. "Micro-, nanomechanical measurements on insect and plant cuticles." Stuttgart Max-Planck-Inst. für Metallforschung, 2005. http://deposit.d-nb.de/cgi-bin/dokserv?idn=979181348.
10
McWilliam, Lyn. "Combined hydrogen diesel combustion : an experimental investigation into the effects of hydrogen addition on the exhaust gas emissions, particulate matter size distribution and chemical composition." Thesis, Brunel University, 2008. http://bura.brunel.ac.uk/handle/2438/3611.
Abstract:
This investigation examines the effects of load, speed, exhaust gas recirculation (EGR) level and hydrogen addition level on the exhaust gas emissions, particulate matter size distribution and chemical composition. The experiments were performed on a 2.0 litre, 4 cylinder, direct injection engine. EGR levels were then varied from 0% to 40%. Hydrogen induction was varied between 0 and 10% vol. of the inlet charge. In the case of using hydrogen and EGR, the hydrogen replaced air. The load was varied from 0 to 5.4 bar BMEP at two engine speeds, 1500 rpm and 2500 rpm. For this investigation the carbon monoxide (CO), total unburnt hydrocarbons (THC), nitrogen oxides (NOX) and the filter smoke number (FSN) were all measured. The in-cylinder pressure was also captured to allow the heat release rate to be calculated and, therefore, the combustion to be analysed. A gravimetric analysis of the particulate matter size distribution was conducted using a nano-MOUDI. Finally, a GC-MS was used to determine the chemical composition of the THC emissions. The experimental data showed that although CO, FSN and THC increase with EGR, NOX emissions decrease. Inversely, CO, FSN and THC emissions decrease with hydrogen, but NOX increases. When hydrogen was introduced the peak cylinder pressure was increased, as was the maximum rate of in-cylinder pressure rise. The position of the peak cylinder pressure was delayed as hydrogen addition increased. This together with the obtained heat release patterns shows an increase in ignition delay, and a higher proportion of premixed combustion. The experimental work showed that the particulate matter size distribution was not dramatically altered by the addition of EGR, but the main peak was slightly shifted towards the nucleation mode with the addition of hydrogen. Hydrogen addition does not appear to have a large effect on the chemical composition of the THC, but does dramatically decrease the emissions.
11
Bacha, Kenza. "Interaction entre les carburants diesel et biodiesel et les composants du système d'injection diesel." Thesis, Mulhouse, 2016. http://www.theses.fr/2016MULH4471.
Abstract:
Le système d’injection Diesel doit résister à des conditions opératoires (pression, température) de plus en plus sévères, et être compatible avec les évolutions du carburant diesel, telles que l’introduction des Esters Méthyliques d’Acide Gras (EMAG) et l’utilisation de différents additifs, qui peuvent affecter la durabilité des véhicules, suite à la formation de dépôts. L’objectif des travaux de cette thèse est la compréhension des mécanismes de formation des dépôts issus de l’oxydation des carburants et la détermination des paramètres majeurs participant aux interactions dépôts-substrats (état de surface, matériaux, géométrie, thermique…). Deux études ont été abordées dans cette thèse. La première étude porte sur l’oxydation accélérée des carburants Diesel, des EMAG et des mélanges Diesel/EMAG en phase liquide en utilisant le moyen d’essai PetroOxy, la cinétique d’oxydation a été déterminée pour les différents carburants et la caractérisation des produits d’oxydation a été effectuée utilisant les moyens d’analyse (FTIR-ATR, ATG/DTG et GC/MS). La seconde étude est dédiée à la reproduction du dépôt sur les substrats en (aluminium, acier inoxydable, PEEK, revêtement or sur aluminium, revêtement silcoklean sur acier inoxydable) en utilisant le moyen d’essai Micro Cokage et la caractérisation du dépôt obtenu dans chaque cas en utilisant les moyens d’analyse (FTIR-ATR, ATG/DTG, FEG et XPS). Les résultats de ces travaux ont permis de déterminer l’impact de la nature et du taux d’EMAG ajouté au Diesel sur la stabilité à l’oxydation des carburants ; de mettre en place une hypothèse de formation de dépôt à partir de l’oxydation des carburants en phase liquide jusqu’à la formation de nanoparticules de dépôt sphériques ; et déterminer l’impact du substrat sur la formation et l’adhésion du dépôt à la surface du matériauDiesel injection system must withstand more severe operating conditions (pressure, temperature), and be compatible with the evolution of diesel fuel, such as the introduction of Fatty Acid Methyl Esters (FAME) and use of different additives, which may affect the durability of the vehicle, following the formation of deposits. The objective of this work is to understand the mechanisms of deposit formation from fuel oxidation and determine the major parameters involved in deposit-substrate interactions (surface condition, materials, geometry, temperature...). Two studies were discussed. The first study focuses on the liquid phase accelerated oxidation of Diesel fuel, FAME and mixtures (Diesel / FAME) using PetroOxy device, the oxidation kinetic was determined for the different fuels and characterization of oxidation products was carried out using the (FTIR-ATR, ATG / DTG and GC / MS). The second study was dedicated to the reproduction of deposit on different substrates (aluminum, stainless steel, PEEK, aluminum coating on gold, silcoklean coating on stainless steel) using the Micro Coking device, and characterization of the deposit obtained in each case using (FTIR-ATR, ATG / DTG, XPS and FEG). The results of this work permit to determine the impact of FAME nature and FAME concentration on fuel oxidation stability; an hypothesis was proposed to explain deposit formation
12
Osika, Oleg. "Stability of micro-grids and inverter-dominated grids with high share of decentralised sources." Kassel : Kassel Univ. Press, 2005. http://deposit.d-nb.de/cgi-bin/dokserv?idn=982006888.
13
Guiral, Vega Juan Sebastian. "Textural and Mineralogical Characterization of Li-pegmatite Deposit: Using Microanalytical and Image Analysis to Link Micro and Macro Properties of Spodumene in Drill Cores. : Keliber Lithium Project, Finland." Thesis, Luleå tekniska universitet, Mineralteknik och metallurgi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70422.
Abstract:
Lithium represents one of the strategic elements for the rest of the 21st century due to its increasing demand in technological applications. Therefore, new efforts should be focused on the optimization of mineral characterization processes, which link the ore properties with its behaviour during downstream processes. These efforts should result in reducing operational risks and increasing resources utilization. The methodology presented in this study is based on the application of several classification techniques, aiming the mineral and textural characterization of two spodumene pegmatite deposits within the Keliber Lithium Project. Twelve textural classes have been proposed for the textual classification of the ore, which have been defined through the recognition of the main mineral features at macro- and micro-scale. The textural classification was performed through the application of drill core logging and scanning electron microscopy. Six classes are proposed to describe the characteristics of the spodumene ore. Six additional classes describe the main properties of the rocks surrounding the ore zone. Image analysis was implemented for the generation of mineral maps and the subsequent quantification of spodumene and Li2O within the analysed drill core images. The image segmentation process was executed in Fiji-ImageJ and is based on eight mineral classes and a set of seven feature extraction procedures. Thus, quantification of spodumene and Li2O is estimated by textural class. Hyperspectral images were used as a reference for assessing the estimations made through images analysis. A machine learning model in Weka allowed forecasting the behaviour of the twelve textural classes during spodumene flotation. This model is fed by metallurgical data from previous flotation tests and uses Random Forest classifier. The proposed methodology serves as an inexpensive but powerful approach for the complete textural characterization of the ore at Keliber Lithium Project. It provides information about: (1) mineral features at different scales, (2) spatial distribution of textures within the pegmatite body, (3) quantification of spodumene and Li2O within the drill cores and (4) processing response of each textural class. However, its application requires wide knowledge and expertise in the mineralogy of the studied deposits.Thesis Presentation.
Textural and Mineralogical Characterization of Li-pegmatite Deposit: Using Microanalytical and Image Analysis to Link Micro and Macro Properties of Spodumene in Drill Cores. Keliber Lithium Project, Finland.
14
SITBON, STEPHANE. "Etude de films minces de nitrure de silicium deposes a basse temperature par plasma multipolaire micro-onde. Application aux structures si/si#3n#4 et inp/si#3n#4." Paris 7, 1996. http://www.theses.fr/1996PA077136.
Abstract:
Les films minces dielectriques deposes a basse temperature presentent actuellement et presenteront dans le futur de multiples applications pour repondre aux nouvelles specifications de l'industrie de la micro-electronique et de l'opto-electronique. Nous presentons dans ce memoire, l'etude et l'optimisation du depot de films minces de nitrure de silicium deposes dans un type de reacteur a plasma micro-onde: le reacteur a resonance cyclotronique repartie (rcer). De nombreux moyens de caracterisation ont ete employes, pour maitriser le depot, tels que la spectroscopie d'emission optique pour l'analyse du plasma, l'ellipsometrie spectroscopique et a annulation pour determiner l'epaisseur et l'indice des films, la spectroscopie d'absorption infra-rouge pour elucider la nature des liaisons chimiques. La composition atomique des films a ete determinee par microanalyse nucleaire et par spectroscopie d'electrons d'auger. La premiere partie de ce travail concerne l'evolution des proprietes physico-chimiques des films de nitrure de silicium rcer realises a partir du melange gazeux de silane et d'azote, en fonction de la composition de la phase gazeuse (n#2/sih#4) et de la puissance micro-onde. Une phase gazeuse fortement diluee en silane et une puissance micro-onde elevee permettent d'elaborer des films denses, legerement sur-stoechiometriques en azote. Dans la deuxieme partie pour confirmer notre point de fonctionnement, nous presentons un ensemble de mesures electriques realisees sur des structures mis (al/sin/si et al/sin/inp). Les valeurs du champ critique et de la densite d'etats d'interface, deduites des caracteristiques respectivement i(v) et c(v) sont les plus elevees dans le cas de l'inp. Toutefois, le mecanisme de conduction dominant est celui de frenkel-poole, quelle que soit la nature du substrat, la valeur de la resistivite etant de 10#1#6 ohm. Cm
15
Thieme, Michael, Christa Blank, de Oliveira Aline Pereira, Hartmut Worch, Ralf Frenzel, Susanne Höhne, Frank Simon, Lewis Hilton G. Pryce, and Aleksandr J. White. "Superhydrophobic Aluminum Surfaces: Preparation Routes, Properties and Artificial Weathering Impact." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-107085.
Abstract:
Among the materials that can be treated in order to impart superhydrophobic properties are many originally hydrophilic metals. For this, they must undergo a sequential treatment, including roughening and hydrophobic coating. This contribution presents various preparation routes along with various characterization methods, such as dynamic contact angle (DCA) measurements, scanning electron microscopy (SEM) and spectroscopic techniques (FT–IRRAS, XPS, EIS).
Micro-rough surfaces of pure and alloyed aluminum were generated most easily by using a modifie Sulfuric Acid Anodization under Intensifie conditions (SAAi). This produces a micro-mountain-like oxide morphology with peak-to-valley heights of 2 μm and sub-μm roughness components. Additionally, micro-embossed and micro-blasted surfaces were investigated. These micro-roughened initial states were chemically modifie with a solution of a hydrophobic compound, such as the reactive f uoroalkylsilane PFATES, the reactive alkyl group containing polymer POMA, or the polymer Teflo ® AF. Alternatively, the chemical modificatio was made by a Hot Filament Chemical Vapor Deposition (HFCVD) of a PTFE layer. The latter can form a considerably higher thickness than the wet-deposited coatings, without detrimental leveling effects being observed in comparison with the original micro-rough surface. The inherent and controllable morphology of the PTFE layers represents an important feature. The impacts of a standardized artificia weathering (WTH) on the wetting behavior and the surface-chemical properties were studied and discussed in terms of possible damage mechanisms. A very high stability of the superhydrophobicity was observed for the f uorinated wet-deposited PFATES and Teflo ® AF coatings as well as for some of the PTFE layer variants, all on SAAi-pretreated substrates. Very good results were also obtained for specimens produced by appropriate mechanical roughening and PTFE coating.
16
Vorberg, Stefan. "Entwicklung von Platinbasis-Superlegierungen Untersuchungen im Mikro- und Nanometerbereich sowie die Ermittlung mechanischer Kennwerte." Berlin Köster, 2006. http://deposit.d-nb.de/cgi-bin/dokserv?id=2857214&prov=M&dok_var=1&dok_ext=htm.
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Murugavel, P. "Thin Films And Sub-Micron Powders Of Complex Metal Oxides Prepared By Nebulized Spray Pyrolysis And Brillouin Scattering Investigations Of Phase Transitions In Solids." Thesis, Indian Institute of Science, 2000. https://etd.iisc.ac.in/handle/2005/217.
Abstract:
The thesis consists of two parts. Part 1 deals with the preparation of thin films and sub-micron powders of complex metal oxides by nebulized spray pyrolysis (NSP) and Part 2 consists of Brillouin scattering studies of solid materials exhibiting interesting phase transitions.
The simple technique of NSP has been employed to prepare thin films of A12O3, PbTiO3, Pb(Zr0.5Ti0.5)O3 (PZT) and PbZrO3 on single crystal substrate. The films were characterized by various techniques for their composition, structure, morphology and dielectric properties. Ferroelectric (FE) films of the configuration FE/LaNiO3/SiO2/Si (FE = PbTiO3 and PZT), wherein the LaNiO3 barrier electrode was also deposited on the SiO2/Si substrate by NSP, have been investigated. The films exhibit satisfactory ferroelectric properties. PbZrO3 films deposited on LaNiO3/SiO2/Si substrates show good features, including a reversible AFE ↔ FE transition. Sub-micron particles of TiO2, ZrO2, Pb(Zr0.5Ti0.5)O3, Al2O3, S1O2 and mullite have been prepared by NSP and characterized by various techniques.
Brillouin scattering has been used, for the first time, not only to characterize the Peierls transition but also the incommensurate to commensurate transition in the one-dimensional blue bronze, K0.3M0O3. The charge density wave transition in NbSe2 has also been investigated by Brillouin scattering. The charge ordering and antiferromag-netic transitions in single crystals of the rare earth manganates, Nd0.5Ca0.5MnO3 and Pr0.63Ca 0.37MnO3, have been investigated by Brillouin scattering. It is noteworthy that the temperature variation of the Brillouin shift and intensity parallel to that of the magnetization, thereby throwing light on magnetic excitations in charge-ordered state. Brillouin scattering investigations of C60 and C70 films have yielded values of the elastic moduli.
18
Thieme, Michael, Christa Blank, de Oliveira Aline Pereira, Hartmut Worch, Ralf Frenzel, Susanne Höhne, Frank Simon, Lewis Hilton G. Pryce, and Aleksandr J. White. "Superhydrophobic Aluminum Surfaces: Preparation Routes, Properties and Artificial Weathering Impact." Technische Universität Dresden, 2009. https://tud.qucosa.de/id/qucosa%3A26716.
Abstract:
Among the materials that can be treated in order to impart superhydrophobic properties are many originally hydrophilic metals. For this, they must undergo a sequential treatment, including roughening and hydrophobic coating. This contribution presents various preparation routes along with various characterization methods, such as dynamic contact angle (DCA) measurements, scanning electron microscopy (SEM) and spectroscopic techniques (FT–IRRAS, XPS, EIS).
Micro-rough surfaces of pure and alloyed aluminum were generated most easily by using a modifie Sulfuric Acid Anodization under Intensifie conditions (SAAi). This produces a micro-mountain-like oxide morphology with peak-to-valley heights of 2 μm and sub-μm roughness components. Additionally, micro-embossed and micro-blasted surfaces were investigated. These micro-roughened initial states were chemically modifie with a solution of a hydrophobic compound, such as the reactive f uoroalkylsilane PFATES, the reactive alkyl group containing polymer POMA, or the polymer Teflo ® AF. Alternatively, the chemical modificatio was made by a Hot Filament Chemical Vapor Deposition (HFCVD) of a PTFE layer. The latter can form a considerably higher thickness than the wet-deposited coatings, without detrimental leveling effects being observed in comparison with the original micro-rough surface. The inherent and controllable morphology of the PTFE layers represents an important feature. The impacts of a standardized artificia weathering (WTH) on the wetting behavior and the surface-chemical properties were studied and discussed in terms of possible damage mechanisms. A very high stability of the superhydrophobicity was observed for the f uorinated wet-deposited PFATES and Teflo ® AF coatings as well as for some of the PTFE layer variants, all on SAAi-pretreated substrates. Very good results were also obtained for specimens produced by appropriate mechanical roughening and PTFE coating.
19
Murugavel, P. "Thin Films And Sub-Micron Powders Of Complex Metal Oxides Prepared By Nebulized Spray Pyrolysis And Brillouin Scattering Investigations Of Phase Transitions In Solids." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/217.
Abstract:
The thesis consists of two parts. Part 1 deals with the preparation of thin films and sub-micron powders of complex metal oxides by nebulized spray pyrolysis (NSP) and Part 2 consists of Brillouin scattering studies of solid materials exhibiting interesting phase transitions.
The simple technique of NSP has been employed to prepare thin films of A12O3, PbTiO3, Pb(Zr0.5Ti0.5)O3 (PZT) and PbZrO3 on single crystal substrate. The films were characterized by various techniques for their composition, structure, morphology and dielectric properties. Ferroelectric (FE) films of the configuration FE/LaNiO3/SiO2/Si (FE = PbTiO3 and PZT), wherein the LaNiO3 barrier electrode was also deposited on the SiO2/Si substrate by NSP, have been investigated. The films exhibit satisfactory ferroelectric properties. PbZrO3 films deposited on LaNiO3/SiO2/Si substrates show good features, including a reversible AFE ↔ FE transition. Sub-micron particles of TiO2, ZrO2, Pb(Zr0.5Ti0.5)O3, Al2O3, S1O2 and mullite have been prepared by NSP and characterized by various techniques.
Brillouin scattering has been used, for the first time, not only to characterize the Peierls transition but also the incommensurate to commensurate transition in the one-dimensional blue bronze, K0.3M0O3. The charge density wave transition in NbSe2 has also been investigated by Brillouin scattering. The charge ordering and antiferromag-netic transitions in single crystals of the rare earth manganates, Nd0.5Ca0.5MnO3 and Pr0.63Ca 0.37MnO3, have been investigated by Brillouin scattering. It is noteworthy that the temperature variation of the Brillouin shift and intensity parallel to that of the magnetization, thereby throwing light on magnetic excitations in charge-ordered state. Brillouin scattering investigations of C60 and C70 films have yielded values of the elastic moduli.
20
Mayer, Miriam. "Vielfalt und Konsonanz in der Berichterstattung über Ereignisse und Akteure eine Inhaltsanalyse von Fernsehnachrichten und Tageszeitungen auf der Mikro-Ebene." Berlin Pro-Business-Verl, 2006. http://deposit.d-nb.de/cgi-bin/dokserv?id=3066777&prov=M&dok_var=1&dok_ext=htm.
21
Wochnowski, Jörn. "Chemische Zersetzung zur Funktionalisierung von Oberflächen in Makro-, Meso-, Mikro- und Nanosystemen sowie Untersuchungen zu den katalytischen und optischen Eigenschaften der dargestellten Oberflächen /." Norderstedt : Books on Demand GmbH, 2008. http://deposit.d-nb.de/cgi-bin/dokserv?id=3076528&prov=M&dok_var=1&dok_ext=htm.
22
Yang, Jen-hung, and 楊仁泓. "Analysis of the local electric-field strength in the fabrication of micro-deposits by intermittent micro anode guided electroplating." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/93932052935280198528.
Abstract:
博士國立中央大學
機械工程研究所
97
Micrometer metallic pillars were fabricated by the intermittent micro-anode guided electroplating (MAGE) process in order to study (1) the localization of the pillar bottom, (2) the surface morphology of the pillars and (3) the cross-sectional structure along the axis of the micro pillars. The results and contributions of these studies were summarized as follows. (1). Two modes (i.e., one-step and multi-step) of the MAGE process were employed to explore the localization of localized electrochemical deposition (LECD). Circular area around the pillar bottom on the substrate was measured and its diameter was estimated to define the localization of the micro pillars. A tiny hillock was fabricated in one-step MAGE process. The diameter (i.e., localization) of the circle around the pillar bottom increases with increasing the electric biases between the micro anode and the substrate. In the multi-step MAGE process, the diameter of the circle increases with increasing the pillar height and levels off at a critical localization (Dc). The magnitude of the critical localization was found to be a function of electric bias and the initial gap between the micro anode and the pillar top deposited previously. The less the electric bias and the initial gap in multi-step MAGE, the diameter of the circular area around the pillar bottom is smaller. A model of micro-electroplating is proposed based on an electric strength ratio (i.e., Ecore/Ep) between the conical core strength (Ecore) to the conical periphery strength (Ep) and the electric voltage responsible for the critical localization. The strength ratio can be used as a criterion to predict whether a localization diameter increases or not. (2). Micrometer copper features fabricated by intermittent MAGE revealed different structures depending upon the experimental conditions. A hollow micro tube was developed at 4.0 V with an initial distance of 2μm/step. With decreasing the voltage from 4.0 to 3.2 V but increasing the initial distance from 2 to 25μm/step, a dense copper column with a smooth surface was formed instead of a rough-surfaced tube. The dense column was based on a substrate where revealed a larger area of circle around the column compared to that for the hollow tube. Finite element analysis is useful to establish a model for illustrating different morphologies of the micro features attained from MAGE process. According to this model, the structure is determined by the ratio (i.e., Ee/Et) of field strength at the periphery (Ee) to that in the center (Et) of the location. Hollow tubes were fabricated at a ratio higher than 1.5; dense pillars were attained at a ratio less than 1.0. (3). The internal structure of the micro feature was illustrated by examining the cross-sectional morphology along its axis. Fixing an initial inter-electrode distance of 2μm/step, the intermittent-MAGE conducted at 3.2 to 3.6V led to a micro structure with rough surface and porous internal. With increasing the voltage from 3.6 to 3.8V, a micro tube with rough surface was fabricated. Up to 4.0V, an imperfect micro tube with highly rough surface was formed. The mechanism of LECD under different conditions is illustrated by a sequence of models proposed.
23
Gusviputri, Arwinda, and 楊慎威. "Electrochemical ELISA for Estradiol Based on Chitosan Deposited Micro-platinum Probes." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/2s53ca.
Abstract:
碩士國立臺灣科技大學
化學工程系
103
A convenient method for fabricating a sensitive indirect sandwich type electrochemical ELISA for the detection of estradiol using a chitosan electrodeposited platinum (Pt) wire microelectrode was proposed. In this assay, anti-17β estradiol produced in goat was used as the capture antibody which was immobilized on the chitosan coated Pt wire microelectrode, anti-17β estradiol 6 antibody produced in mouse was used as the detection antibody, and goat anti-mouse IgG conjugated with alkaline phosphatase (AP) was used as the secondary antibody. 4-Aminophenyl phosphate (4-APP) was chosen as the AP substrate and the oxidation potential of the electroactive AP product, 4-amino phenyl (4-AP), on the Pt electrode was determined to be +0.14 V (vs. Ag/AgCl). The electrochemical ELISA was detected by constant potential amperometry at +0.14 V in the Tris buffer (pH 9.0). The sensitivity (limit of detection) of this assay was 0.27 pg/mL with a wide detection range from 0.27 pg/mL up to 100 ng/mL. The assay specificity evaluated by testing the cross-reactivity of the assay against progesterone and 17α-ethynylestradiol was found to be 0.033% and 3.35%, respectively. The calibration curve of this assay tested in serum was also established. In this study, a sensitive, inexpensive, disposable, and easy to be fabricated electrochemical ELISA for estradiol was demonstrated.
24
Rao, K. Yellareswara. "Sputter Deposited Thin Film Cathodes from Powder Target for Micro Battery Applications." Thesis, 2015. http://etd.iisc.ac.in/handle/2005/3825.
Abstract:
All solid state Li-ion batteries (thin film micro batteries) have become inevitable for miniaturized devices and sensors as power sources. Fabrication of electrode materials for batteries in thin film form has been carried out with the existing technologies used in semiconductor industry. In the present thesis, radio frequency (RF) sputtering has been chosen for deposition of cathode material (ceramic oxides) thin films because of several advantages such as precise thickness control and deposition of compound thin films with equivalent composition. Conventional sputtering involves fabrication of thin film using custom made pellet according to the specification of sputter gun. However several issues such as target breaking are inevitable with the pellet sputtering. To forfend the issues, powder sputtering has been implemented for the deposition of various thin film cathodes in an economically feasible approach. Optimization of various process parameters during film deposition of cathode materials LiCoO2, Li2MnO3, LiNixMnyO4, mixed oxide cathodes of LiMn2O4, LiCoO2 and TiO2 etc., have been executed successfully by the present approach to achieve optimum electrochemical performance. Thereafter the optimized process parameters would be useful for selection of cathode layers for micro battery fabrication.
Chapter 1 gives a brief introduction to the Li ion and thin film solid state batteries. It also highlights the advantages of powder sputtering compared to conventional pellet sputtering.
In Chapter 2, the materials used and methods employed for the fabrication of thin film electrodes and analytical characterizations have been discussed.
In chapter 3, implementation of powder sputtering for the deposition of LiCoO2 thin films has been discussed. X-Ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS) and electrochemical investigations have been carried out and promising results have been achieved. Charge discharge studies delivered a discharge capacity of 64 µAh µm-1 cm-2 in the first cycle in the potential range
3.0-4.2 V vs. Li/Li+. The possible causes for the moderate cycle life performance have been discussed.
Systematic investigations for RF power optimization for the deposition of Li2-xMnO3-y thin films have been carried out. Galvanostatic charge discharge studies delivered a highest discharge capacity of 139 µAh µm-1cm-2 in the potential window 2.0-3.5 V. Thereafter, effect of LMO film thickness on electrochemical performance has been studied in the thickness range 70 nm to 300 nm. Films of lower thickness delivered higher discharge capacity with good cycle life than the thicker films. These details are discussed in chapter 4.
In Chapter 5, fabrication and electrochemical performance of LiNixMnyO4 thin films are presented. LMO thin films have been deposited on nickel coated stainless steel substrates. The as deposited films were annealed at 500 °C in ambient conditions. Nickel diffuses in to LMO film and results in LiNixMnyO4 (LMNO) film. These films were further characterized. Electrochemical studies were conducted up to higher potential 4.4 V resulted in discharge capacities of the order of 55 µAh µm-1cm-2.
In chapter 6, electrochemical investigations of mixed oxide thin films of LiCoO2 and LiMn2O4 have been carried out. Electrochemical investigations have been carried out in the potential window 2.0–4.3 V and a discharge capacity of 24 µAh µm-1cm-2 has been achieved. In continuation, TiO2 powder was added to the former composition and the deposited films were characterized for electrochemical performance. The potential window as well as the discharge capacity enhanced after TiO2 doping. Electrochemical characterization has been carried out in the potential window 1.4–4.5 V, and a discharge capacity of 135 µAh µm-1cm-2 has been achieved.
Finally chapter 7 gives overall conclusions and future directions to the continuation of the work.
25
Rao, K. Yellareswara. "Sputter Deposited Thin Film Cathodes from Powder Target for Micro Battery Applications." Thesis, 2015. http://etd.iisc.ernet.in/2005/3825.
Abstract:
All solid state Li-ion batteries (thin film micro batteries) have become inevitable for miniaturized devices and sensors as power sources. Fabrication of electrode materials for batteries in thin film form has been carried out with the existing technologies used in semiconductor industry. In the present thesis, radio frequency (RF) sputtering has been chosen for deposition of cathode material (ceramic oxides) thin films because of several advantages such as precise thickness control and deposition of compound thin films with equivalent composition. Conventional sputtering involves fabrication of thin film using custom made pellet according to the specification of sputter gun. However several issues such as target breaking are inevitable with the pellet sputtering. To forfend the issues, powder sputtering has been implemented for the deposition of various thin film cathodes in an economically feasible approach. Optimization of various process parameters during film deposition of cathode materials LiCoO2, Li2MnO3, LiNixMnyO4, mixed oxide cathodes of LiMn2O4, LiCoO2 and TiO2 etc., have been executed successfully by the present approach to achieve optimum electrochemical performance. Thereafter the optimized process parameters would be useful for selection of cathode layers for micro battery fabrication.
Chapter 1 gives a brief introduction to the Li ion and thin film solid state batteries. It also highlights the advantages of powder sputtering compared to conventional pellet sputtering.
In Chapter 2, the materials used and methods employed for the fabrication of thin film electrodes and analytical characterizations have been discussed.
In chapter 3, implementation of powder sputtering for the deposition of LiCoO2 thin films has been discussed. X-Ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS) and electrochemical investigations have been carried out and promising results have been achieved. Charge discharge studies delivered a discharge capacity of 64 µAh µm-1 cm-2 in the first cycle in the potential range
3.0-4.2 V vs. Li/Li+. The possible causes for the moderate cycle life performance have been discussed.
Systematic investigations for RF power optimization for the deposition of Li2-xMnO3-y thin films have been carried out. Galvanostatic charge discharge studies delivered a highest discharge capacity of 139 µAh µm-1cm-2 in the potential window 2.0-3.5 V. Thereafter, effect of LMO film thickness on electrochemical performance has been studied in the thickness range 70 nm to 300 nm. Films of lower thickness delivered higher discharge capacity with good cycle life than the thicker films. These details are discussed in chapter 4.
In Chapter 5, fabrication and electrochemical performance of LiNixMnyO4 thin films are presented. LMO thin films have been deposited on nickel coated stainless steel substrates. The as deposited films were annealed at 500 °C in ambient conditions. Nickel diffuses in to LMO film and results in LiNixMnyO4 (LMNO) film. These films were further characterized. Electrochemical studies were conducted up to higher potential 4.4 V resulted in discharge capacities of the order of 55 µAh µm-1cm-2.
In chapter 6, electrochemical investigations of mixed oxide thin films of LiCoO2 and LiMn2O4 have been carried out. Electrochemical investigations have been carried out in the potential window 2.0–4.3 V and a discharge capacity of 24 µAh µm-1cm-2 has been achieved. In continuation, TiO2 powder was added to the former composition and the deposited films were characterized for electrochemical performance. The potential window as well as the discharge capacity enhanced after TiO2 doping. Electrochemical characterization has been carried out in the potential window 1.4–4.5 V, and a discharge capacity of 135 µAh µm-1cm-2 has been achieved.
Finally chapter 7 gives overall conclusions and future directions to the continuation of the work.
26
Ou, chang-ying, and 歐長穎. "Electroless Nickel Deposited of Micro-Arc-Oxidized Magnesium Alloy and its Corrosion Behaviors." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/73737829571147697748.
Abstract:
碩士國防大學理工學院
化學工程碩士班
102
Magnesium alloys was developed as a structural material due to it has some excellent properties such as low density, high strength, casting-ability and workability. Therefore, it has high development potential in the industry applications. However, magnesium alloys are sensitive to corrosion and severely limit their application. Many surface treatment techniques have been developed to protect the magnesium alloys such as chemical treatment, oxidation, organic coatings, conversion coating, anodizing or metal coating. In this study, the micro-arc oxidation layer of magnesium alloy has been as the substrate and the catalyst was spread on the surface which make surface has a catalytic activity, and then the process was combined with the aqueous phase prepared with electroless nickel-phosphorus alloy coating. In this paper, SEM was used to observe the surface morphology and cross-section of coatings, the chemical composition of coatings was analyzed by EPMA, the corrosion resistance of coatings was examined by polarization curves and salt spray test, respectively. First, we analyzed the causes that why the corrosion resistance of micro-arc magnesium alloy after electroless nickel will drop down. The result reveals that the micro-arc magnesium alloy in the electroless nickel plating bath will produce a displacement reaction and erode the micro-arc magnesium alloy micro-arc layer and lead to the protective layer of micro-arc decline during electroless nickel processes. In addition, the hydrogen ions caused by the oxidation and reduction reaction between hypophosphite and nickel ions during electroless nickel process also decrease the corrosion resistance of the micro-arc magnesium alloy layer. Moreover, the chemical reaction rate within initial metal interface how to affect the corrosion resistance of the micro-arc magnesium alloy after electroless nickel process also be studied. The results presents that the rapid initial reaction rate will result in producing more hydrogen ion during electroless nickel process and lead to corrode micro arc layer seriously. The protection of micro-arc magnesium alloy layer will be decreased due to the corrosion of micro arc layer during electroless nickel process. Finally, via comparing various microstructure of micro-arc magnesium alloy, we found that the less defects within micro arc layer the better corrosion resistance of micro arc layer during electroless nickel process and after 24 hours of salt spray testing the surface of micro arc layer only generated few corrosion points.
27
CHEN, CHI-AN, and 陳麒安. "Nickel-phosphorus alloys deposited on magnesium alloy micro-arc oxidation layer using different catalysts." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/70561224320343144235.
Abstract:
碩士國防大學理工學院
化學工程碩士班
105
Magnesium-lithium alloy(LZ91) is currently the lightest of practical metal, its advantages are light (similar to plastic), higher strength, specific rigidity and better heat dissipation. Magnesium alloy is extremely to corrosion which seriously affecting its application in real life. In this study, Micro - arc oxidation of wet - type method was used to prepare a oxide film on magnesium alloy which improves corrosion resistance. The surface of the magnesium-lithium alloy treated by micro-arc oxidation was not beautiful. In corrosive environment, the outside layer is prone to failure. In order to solve this problem, the outer layer of oxide film to seal, which can prevent corrosion factor invasion. The oxide layer is without any activity, which needs to soak in catalytic active solution, therefore nickel ions can be catalyzed and evenly coated on the micro-arc oxidation of magnesium alloy to enhance the corrosion resistance and aesthetics. First discussion different voltage on corrosion resistance of micro-arc oxidation layer. After finding the best operating conditions, and then explore the characteristics of different catalysts and the effect of coating on the best conditions of micro - arc oxidation. Finally, the micro-arc magnesium oxide alloy with different catalyst was coated with nickel-phosphorus layer by electroless plating, and observe the corrosion resistance. In the experiment, the surface morphology and cross-sectional were observed by scanning electron microscopy(SEM). Electrochemical test linear polarization curve and salt spray to detect the corrosion resistance. The size of the catalyst particles is analyzed by a light scattering instrument. Catalyst stability is analyzed by stability analysis instrument. Contact angle analysis instrument analyzes the affinity between the catalyst and the micro-arc oxidation layer. The experimental results show that: the flat and dense oxide layer was prepared at a Bipolar pulses voltage of 400 V, which corrosion resistance is better. In the corrosion resistance test, the electrochemical test obtained corrosion current of 1.4 × 10-7 A / cm2, salt spray test can be passed 48 hours. Next, with different catalyst on the best micro-arc oxidation layer. The results show that the pH value of the 7 N type catalyst has a better performance. Its effective particle size is the smallest, the stability is better. The affinity with the micro-arc oxide layer is best and the corrosion resistance to the micro-arc oxide layer is less affected. Subsequent to electroless nickel-phosphorus layer, which can pass salt spray 24 hours . It is the best process conditions.
28
Chen, Ming-Shan, and 陳明山. "The drilling performance and hole quality of multilayer diamond-like carbon deposited on micro-drill." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/98817249896773949509.
Abstract:
碩士建國科技大學
自動化工程系暨機電光系統研究所
101
The study is to research the drilling performance of a-C:H:Zr coatings prepared by sputtering graphite ,zirconium targets ,CH4 and C2H2 used unbalanced magnetron sputtering system. The stusy contains three stages .The objective is study the influence of Zr target current on the drilling properties of coatings in the first stage. It change the interlayer was from one multilayer to four multilayer in the second stage. Base on the second stage, results the coating hardness is low. In order to improve the hardness, the coating have been designed a multilayer structure. It contain both hard and soft layer in the multilayer coating in the third stage. The drilling performance of the coated micro-drills is evaluated by conducting high-speed through-hole drilling tests using printed circuit board (PCB) specimens. The service life of the coated micro-drills is assessed utilizing three different criteria, namely the nail head ratio, surface roughness of the drilled hole, and diameter of drilled hole, respectively. The result display that the S3 coating process the test drilling performance and the highest drilling life time. It can improve the life time of drilling above 6000 holes drilled.
29
Heng, Ying Cho, and 卓亨穎. "Mechanisms and ellipsometry studies of micro-crystalline silicon film deposited by ion-assisted RF sputtering." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/30816667292172060456.
Abstract:
碩士輔仁大學
物理學系碩士班
101
According to the studies of microcrystalline silicon film deposited by plasma enhance chemical vapor deposition (PECVD), the three kinds of the film’s formation mechanisms are selective etching, surface diffusion, and chemical annealing. In this study, we discussed the formation of microcrystalline silicon films deposited by physical vapor deposition (PVD) of RF sputtering with the above three mechanisms. The silicon films fabricated at various deposition conditions were evaluated by optical spectrometer and ellipseometer to analyze the optical properties and to support the film’s formation mechanisms we postulated. From the investigations of XRD, the distance between Si target and substrate, and the deposition rate, the selective etching was not the main factor of micro-crystallization of silicon film. However, the chemical annealing may be the first reason and the surface diffusion be the secondary reason as evaluating optical properties of the silicon films fabricated with ion-assisted deposition and with heating from filament of end Hall ion source in RF sputtering. The energy from ion bombardment inputted into and enhanced the formation of the microcrystalline silicon film. Finally, the microcrystalline film fabricated by ion-assisted RF sputtering deposition in the total pressure of 1.75×10-2 Torr, at the partial hydrogen pressure of 40%, had the best crystalline structure. This result also supports the mechanism of crystallization our postulated.
30
Lin, Jian-Liang, and 林建良. "Diamond deposited from CH-COand CH-COgas systems using micro-ware plasma CVD." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/53292811250759370559.
31
Bankoti, A. K. S. "Synergistic study on electrochemically deposited thin film with a spectrum from micro to nano range structures." Thesis, 2009. http://ethesis.nitrkl.ac.in/1462/1/Anil_Thesis_Final.pdf.
Abstract:
Thin films are deposited onto bulk materials (substrates) to achieve properties unattainable or not easily attainable in the substrates alone. The film thickness usually varies from few nanometers to a maximum value of 1 μm. Cavitation, irradiation of liquid with high intensity ultrasound, as a means of altering the crystallization process is achieved by the repeated creation and collapse of microscopic bubbles inside the solution. It is at the solid-liquid interface that electrochemical techniques may be employed to detect the possible influence of sonication on electrochemical nucleation and growth of clusters. In this work we prepare the copper thin film by sonoelectrosynthesis method at different temperature, acid and concentration of electrolyte. Films are characterized by XRD, SEM, AFM, and study of the mechanical properties is done by nanaoidentation. Scahifker and Hills model was used for study of nucleation and growth phenomena for electrochemically deposited thin film by cyclic voltammetry and chronoamperometry. A potential of 450 mV (100 mV negative than the Nernst potential) was selected for the deposition procedure for all the conditions. The sole impact of sonication was experimented before the study of the coupling effect and was found to favor nucleation ahead of growth. The evidence of secondary nucleation in ultrasonic condition was also observed. The thickness of films lies in the range of 400-500 nm. The phases of the deposits are confirmed by the XRD analysis. The nucleation population density got increased from a low value to high value of acid concentrations. Comparison with the theoretical models, it is apparent that copper follows progressive nucleation mode in increasing acid concentration. Hydrogen evolution was also imperative at increasing acid concentrations, however, ultrasound capable of degassing produced hydrogen free adherent surfaces. The facts are also confirmed by the morphological analysis by SEM and AFM. The same trend is observed for the films with low temperatures. Among all the depositions copper films at – 4 °C is the smoothest. Increasing metal ion concentrations produces finer and harder deposits. Films are rougher at 0.1 M as compared to that of 0.025 M. The grains are found to vary from 400 nm to 50 nm at various conditions with the average roughness factors from 300 nm to 14 nm.
32
Wang, Yin-Jie, and 王胤傑. "Design and Fabrication of Screen Printed Thick Film and Stacked Aerosol Deposited Multilayer Piezoelectric Micro Energy Harvester." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/01648165897830033223.
Abstract:
碩士國立臺灣大學
工程科學及海洋工程學研究所
103
The concept of “Internet of Things” has become a hot topic in recent years, and the need for sensing devices has risen substantially. Due to the advancement of VLSI technology, the power consumption of micro-scale smart devices has gradually reduced to tens of microwatts. As such, the ability to produce this level of energy in large quantity has become an important task. Traditional use of power cord to supply energy or the usage of battery has proven to be quite inconvenient, for the placement of the devices may be hard to reach, and the lifetime of such power sources are often unreliable. A method that utilizes the environment to provide a self-powered electrical energy will be beneficial. Solar power can be used as a general resource, but in many cases the devices are installed in enclosed areas where lighting is insufficient. Therefore, vibrational energy sources has become a primary target for energy extraction. In order to create a piezoelectric energy harvester that is suitable to provide energy for further applications, a screen-printing technique to create thick film is discussed in chapter three of this paper. The technique is used to deposit high quality piezoelectric film in a short amount of time. In chapter four, the structure and design of the piezoelectric harvester is discussed, to improve the overall output of the harvester. Experimental results indicate that the PZT piezoelectric thick film has avoided the oxidation and vaporization of lead from the material when a sintering process has been done. The high temperature sintering process can preserve a better piezoelectric characteristic. Additionally, Aerosol deposition method is used to fabricate a multilayer micro energy harvester. By poling each layer’s dipole in parallel form, and connecting each layer in parallel to measure the performance, we can obtain the optimal load to be 15kΩ, and the optimal output power to be 80.14μW when the device is operating at its resonant frequency of 121.5Hz and under 1g acceleration. In comparison to a single-layer structured device, the output load resistance has been lowered to almost 10 times, and the output current at the optimal load has increase to about three times.
33
Wu, Han-Hua, and 吳函樺. "Micro-Raman spectroscopy and Transmission Electron Microscopy investigation of YBCO thin films deposited by RF-magnetron sputtering." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/82293177786854807521.
Abstract:
碩士國立中興大學
物理學系所
101
In this work, YBCO films were deposited by RF magnetron sputtering on (100) strontium titanate substrate. X-ray diffactometry, Raman spectroscopy and field emission transmission electron microscopy were used to investigate the lattice structure of the YBCO films. The superconducting critical temperature varied significantly with the temperature of the substrate. Raman spectroscopy revealed that the lattice structure at low substrate temperature was visibly orientated a-axis. The a-axis orientation and lattice defects in the microscopic structure were observed. And the area of the a-axis orientation was small and disordered. Raman spectroscopy revealed that the a-axis orientation became weak as the substrate temperature increased. And the area that exhibited that orientation increased in the microscopic structure. Finally, no a-axis orientation was observed at a substrate temperature of 730 ℃. The orientations of YBCO films were clearly and easily observed by Raman spectroscopy. A suitable area can be to patterned to increase the success rate of Josephson junctions and Superconducting Quantum Interference Devices.
34
Jin, Zhe. "Low-loss coupling to sub-micron thick deposited film rib and nanowire waveguides by vertical tapering." Master's thesis, 2012. http://hdl.handle.net/1885/151722.
Abstract:
The main purpose of this thesis is to present work towards theoretical and experimental characterization of a vertical taper-based spot size converter to increase the coupling efficiency between a single-mode fibre and rib and nanowire waveguides. Simulations of taper design parameters have been investigated in this thesis and optimised designs established for coupling to high numerical aperture fibres. These have then been experimentally implemented, and the techniques and fabrication processes have been discussed in detail. The experimental measurements of the finished devices are presented and analysis undertaken to determine areas for future improvement.
35
Pan, Chin-Chang, and 潘錦昌. "Micro/Nano Mechanical, Material Properties and Tribological Performance of a-C:H(N) Thin Films Deposited by Low-Temperature Ion Beam Process." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/g3us7g.
Abstract:
碩士國立成功大學
機械工程學系碩博士班
90
The adhesion effects to the load-depth curves of nano-indentation test and the theoretical relation of micro/nano hardness are researched in this study. The effect of nitrogen containing and film thickness to the a-C:H and a-H(N) diamond like carbon film structures and micro/nano mechanical and tribological properties is involved, too. The hardness and Young’s modulus are measured by nano-indentation performed by NanoTest, and the capillary attraction and van der Wall force calculated in order to assess the adhesion effect of different nitrogen containing and film thickness. In the residual stresses of films, the profile data are measured before and after coating by 3-D profilemeter and the radius of curvature are calculated by regression; therefore the residual stress can be obtained by the radius of curvature before and after coating according to the stress theory and the effect of the residual stress can be discussed. In measuring tribological properties, we scanned and scratched sample surfaces by Scanning Probe Microscope and NanoTest with different speeds and loads. In examining samples, we measured composition and bonding by ESCA and Raman spectrum, and measured the optical properties by Ellipsometer. According to the experimental results, the adhesion effects to the load-depth curves are significant as the indentation depth is lower than 50 nm, and the effect gets larger as depth decreases. And we found that the very thin (about 50 nm) diamond like carbon film has large hardness and Young’s modulus and excellent anti-wear property and surface roughness. There are two characters in this study: (1) considering the capillary attraction and van der Wall force under nano-scale and observing the fact that the hardness without considering adhesion effect is much larger; (2) Obtaining hardness by the energy method and considering the effects of elastic work due to elastic recovery and adhesion work due to adhesive forces.
36
Fisher, Louise. "Hydrothermal processes at the Osborne Fe-Oxide-Cu-Au deposit, N.W. Queensland: integration of multiple micro-analytical data sets to trace ore fluid sources." Thesis, 2007. https://researchonline.jcu.edu.au/4782/1/01front.pdf.
Abstract:
The Osborne mine exploits one of several significant iron oxide-copper gold (IOCG)
deposits in the eastern part of the Proterozoic Mount Isa Inlier (Cloncurry District) in
NW Queensland. Cu-Au bearing sulphides at Osborne are associated with volumes of
massive, coarse grained quartz (silicification) which was precipitated both pre- and synore
deposition. This extensive quartz is a feature unique to Osborne and make it ideal
for a fluid inclusion study. The ore forming fluids were examined by several bulk and
microanalytical techniques. The fluid history of the deposit has been evaluated by
microscope petrography and the physical conditions under which the fluids were
trapped, and their compositions were estimated using microthermometry, laser Raman
spectroscopy, proton induced X-ray emission (PIXE) and laser ablation inductively
coupled plasma mass spectrometry (LA-ICP-MS). The source of the fluids and their
salinities were studied using combined noble gas and halogen analysis utilising a
neutron activation-mass spectrometric method on bulk samples and PIXE analysis.
Petrographic studies show complex assemblages of fluid inclusions in which both pre and
post-ore depositional ore fluids are identified. Primary multi-solid fluid inclusions
(MS), some with a carbon dioxide component (CB), trapped at 340 - >600oC with ultrahigh
salinity (<64 wt% NaCl equiv.), are correlated with the massive quartz
precipitation event. High salinity (17-38 wt% NaCl equiv) pseudosecondary and
secondary liquid-vapour ± halite fluid inclusions (LVD) were trapped at 105-292oC and
lie on trails that emanate from chalcopyrite and are interpreted to relate to Cu-Au
mineralisation and a second phase of quartz deposition. The decrease in temperature
and salinity over the period of ore formation is attributed to fluid mixing.
Thermal and mechanical decrepitation of the fluid inclusion populations permitted
semi-selective analysis of different fluid inclusion populations and a comparison of the
noble gas and halogen composition of the ore fluids with those of the pegmatites. The
halogen data for the Osborne deposit indicate multiple sources of salinity suggesting
mixing between at least two components; the fluids with the highest values of Br/Cl =
3.8 ×10-3 and I/Cl = 27.4 × 10-6 are similar to bittern brine compositions and those with
the lowest values of Br/Cl = 0.3×10-3 and I/Cl = 2.4 ×10-6 are similar to halite
dissolution waters. Values for pegmatitic quartz hosted fluids fall within these ranges.
The data are consistent with mixing between crustal fluids of diverse origin. 40Ar/36Ar
values of <2000 and 36Ar concentrations of 1- 6 ppb are most similar to sedimentary
formation waters but a metamorphic component, derived from devolatisation reactions
during regional metamorphism, can not be excluded. The similar values obtained for
samples of pegmatitic quartz support the presence and inclusion of ore fluids at the time
of pegmatite anatexis. The moderately high 36Ar concentrations in the ore fluids and
their low 40Ar/36Ar values preclude the involvement of magmatic fluids derived from Atype
granites with a deep crust or mantle origin.
Compositional data obtained using PIXE and LA-ICP-MS shows significant
compositional variation within single inclusion populations. A two order of magnitude
range of Br/Cl ratios (0.2 – 18 ×10-3) correlates with noble gas and halogen data and
indicates multiple sources of salinity. Low concentrations of copper in the high salinity
ore fluids (Cu<<150ppm) suggest that changes in control factors of copper solubility
were important in the formation of the deposit. At temperatures of 600oC, the Osborne
ore fluids would be undersaturated with respect to chalcopyrite. Cooling, dilution and redox changes caused by interaction with host rocks and/or fluid mixing are interpreted
to be the main controls on deposition.
Geochemical modelling of the ore forming processes, using HCh, suggests that a redox
switch from hematite-stable conditions to magnetite-stable conditions could have
triggered chalcopyrite precipitation during rock-buffered fluid mixing. Modelling
suggests highest ore grades would be associated with pyrrhotite-bearing assemblages.
Data collected during this study indicate that cooling, dilution and redox changes
caused by interaction with host rocks and/or fluid mixing are likely to have been the
main controls on deposition at the Osborne deposit. Furthermore, halogen and noble
gas data provide strong evidence that magmatic fluids are not a ubiquitous component
of IOCG ore forming systems.
37
Morais, Bruno Daniel Pinto. "Characterization of the micro and nanostructure of biocide nanocomposites based in transparent titanium dioxide nanocoatings deposited on polymeric foils for food packaging applications." Master's thesis, 2015. http://hdl.handle.net/1822/35015.
Abstract:
Dissertação de mestrado em Biophysics and BionanosystemsPackaging provides containment and protects food products during distribution and storage from external and internal unfavorable conditions, such as water vapor, microorganisms, gases and odors. Nowadays consumers’ demands require the development functional packaging systems with enhanced quality and self-life such as active food packaging which directly interacts with the food product through a mechanism triggered by intrinsic and/or extrinsic factors. Due to the rise in deaths and hospitalizations related with food poisoning and foodborne diseases, much effort has been made to design efficient antimicrobial active packaging systems. Many antimicrobial agents are available, including both organic and inorganic. One of these potential agents is titanium dioxide (TiO2). Since the discovery of the photocatalytic potential of TiO2, there has been an increase in research and products that take advantage of this process for depollution and disinfection applications and, more recently, antimicrobial food packaging. Its strong photocatalytic yield is the result of the high oxidizing power under UV-light. Other attractive properties include high chemical stability, non-toxic to both human and the environment, and high availability and low cost. Despite its limitations, such charge recombination rate and need of an UV-light source, which decrease the overall effectiveness of photocatalytic, intensive research is turning TiO2 into one of the most effective antimicrobial agents in food packaging applications. With this in mind, TiO2 thin films were deposited on PET/PLA using pulsed DC magnetron sputtering technique, at room temperature. The films were characterized for their morphology (SEM), crystalline structure (XRD), optical properties and thickness (UV-vis-NIR spectrophotometry and FTIR), and wettability (dynamic contact angle). The photocatalytic activity was evaluated by photodegradation of rhodamine B under UV irradiation. The films produced were predominantly amorphous and showed no sign of photocatalytic activity due the lack of crystallinity structure thus being incapable of producing an antimicrobial response. However, some samples showed potential for crystalline growth, evidenced by broad protuberances in 2θ regions associated with anatase and rutile phases. All depositions in PLA exceeded the Tg, which lead to a complete dismissal of this polymer, while a few depositions in PET managed to keep the temperature below the polymer’s Tg, avoiding deformation and loss of mechanical viability of the polymer.
As embalagens providenciam contenção e protegem os alimentos durante a sua distribuição e armazenamento de condições externas e internas desfavoráveis como o vapor de água, microorganismos, gases e odores. Hoje em dia, as exigências dos consumidores requerem o desenvolvimento de sistemas funcionais para embalagens com qualidade e “tempo de prateleira” melhorados como, por exemplo, as embalagens activas que interagem directamente com o produto alimentar através de mecanismos activados por fatores intrínsecos e/ou extrínsecos. Devido ao crescente aumento de mortes e hospitalizações relacionadas com intoxicação alimentares e doenças transmitidas por alimentos, muito esforço tem sido dado ao design de embalagens alimentares com sistemas antimicrobianos eficientes. Muitos agentes antimicrobianos estão disponíveis, tanto orgânicos como inorgânicos. Um destes é o dióxido de titânio (TiO2). Desde a descoberta do seu potencial fotocatalítico, tem havido um aumento na investigação e produtos que se aproveitam desta característica, incluíndo aplicações na descontaminação e desinfecção e, mais recentemente, aplicações antimicrobianas nos alimentos. O seu forte potencial fotocatalítico é derivado de um elevado poder oxidativo, quando exposto a luz UV. Outras características incluem estabilidade química, não toxicidade para os humanos e o ambiente, disponibilidade e baixo custo. Apesar das suas limitações, como a taxa de recombinação de cargas e necessidade de um fon te e luz UV, que diminuí a eficiência do processo fotocatalítico, investigação está a tornar o TiO2 num dos principais agentes antimicrobianos de embalagens alimentares. Com isto em mente, filmes de TiO2 foram depositados em PET/PLA utilizando pulverização catódica por magnetrão pulsado. Os nanocompósitos produzidos foram caracterizados quanto à sua morfologia (SEM), estrutura cristalina (XRD), propriedades ópticas e espessura (espectrofotometria UV-vis-NIR e FTIR) e molhabilidade (ângulo de Contacto). A actividade fotocatalítica foi avalição por fotodegradação do corante rodamina B sob luz UV. Os filmes produzidos são predominantemente amorfos e não apresentam actividade fotocatalítica devido à ausência de uma estrutura cristalina, portanto são incapazes de produzir uma resposta antimicrobiana. Alguuns filmes apresentam potencial para crescimento cristalino devido à presença de proturberâncias em regiões associadas à fase anatase e rutile do TiO2 As temperaturas atingidas nas deposições ultrapassam a Tg do PLA mas no caso das deposições em PET, algumas deposições conseguem manter-se abaixo do mesmo.
38
Yang, Yun-Kai, and 楊雲凱. "Theoretical Analysis of Adhesion Energy and Micro/Nano Tribological Performance of a-C:H(N) Thin Films Deposited by Low-Temperature Ion Beam Process." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/w7qppu.
Abstract:
碩士國立成功大學
機械工程學系碩博士班
90
The adhesion energies and critical loads of a-C:H and a-C:H(N) diamond like carbon films coated by ion beam deposition by scratch tests are researched in this study. The effect of nitrogen containing and film thickness to the adhesion energies is involved, too. In the theoretic analysis, the stress and strain distribution of sample under critical load causing film to strip off from substrate are derived from the uniform pressure in spherical shell. By simulating the stress and strain of substrate under scratch test and the continuality of strain between film and substrate, we derived the elastic storage energy of film and calculated the adhesion energy between film and substrate. In experimental parts, the critical loads are measured from scratch test under different scanning speeds and loading rates performed by the NanoTest and the Surface Response Method is used to analyze the measured critical load data. Furthermore, the adhesion energies are modified by the indentation tests. The residual stresses of films are calculated by the surface profiles measured before and after coating by 3-D profilemeter. In examining samples, we measured composition and bonding by Chemical analyzer and Raman spectrum, and measured surface by Atomic Force Microscope. In researching anti-wear properties, we calculated the wear volumes of scratches under different speeds and loads by NanoTest. According to the experimental results, the critical loads are higher as more nitrogen containing; however, the critical load of the film of 66 percent nitrogen containing is very low because of much graphitizing. Under the condition of the same film thickness and nitrogen containing, the higher critical load indicates the smaller residual stress and larger adhesion energy.