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1
Ostřížek, Petr. "Elektrotransportní vlastnosti nanostruktur připravených metodou FIB". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229474.
Testo completoAbstract (sommario):
The aim of this work is fabrication of nanostructures and measurement of their electrotransport properties. There are two different methods used for fabrication - electron beam lithography with sputtering of thin films and focused ion beam with deposition from gas phase. I-V characteristic was measured for characterisation of as prepared nanostructures - wires. Material of wires prepared by using of electron beam lithography was permalloy - an alloy of iron and nickel. Second types of wires prepared by using of chemical vapor deposition induced by focused ion beam was platinum based.
2
Mucke, S. "Herstellung von Nanometer-Strukturen mittels feinfokussiertem Ionenstrahl (FIB)". Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-28940.
Testo completoAbstract (sommario):
Feinfokussierte Ionenstrahlen dienen in den Gebieten der Halbleiterindustrie und Materialforschung der Mikro- und Nanostrukturierung. Die vorliegende Arbeit beschäftigt sich mit den beiden Hauptanwendungen von fokussierten Ionenstrahlen, dem Materialabtrag und der ionenstrahlinduzierten Materialabscheidung. Dabei wird die hochauflösende Ionensäule CANION 31Z der Firma Orsay Physics mit Stromdichten von bis zu 10 A/cm2 und mit integriertem Gassystem eingesetzt. Es wird ausführlich auf Anwendungsbeispiele von Fokussierten Ionenstrahlsystemen im Bereich der Industrie und Forschung eingegangen. Schwerpunktmäßig wird die Abscheidung von Wolfram aus dem Precursorgas W(CO)6 (Wolframhexacarbonyl) auf Si und SiO2 als Substrat untersucht, mit dem Ziel, gut leitfähige Drähte (hier im Sinne von Leiterbahnen) mit minimalem Querschnitt herzustellen. Die Optimierung der Ionenstrahl-Parameter dieser Feinfokussierten Ionenstrahlanlage bezüglich der Abscheidung steht im Vordergrund. Dabei wird ein kurzer Einblick in die Theorie der Schichtentstehung beim Abscheidevorgang gegeben. Untersuchungen der erzeugten Strukturen entsprechend der Schichtqualität und der Strukturabmessungen werden erläutert und die Ergebnisse diskutiert. Es konnten Wolframdrähte mit einer Länge von 20 ... 100 µm, einer Breite von minimal 150 nm und einer Höhe von maximal 600 nm angefertigt werden. Die Zusammensetzung der Drähte in Abhängigkeit der Prozessparameter wurde mittels AES bestimmt. Im optimalen Fall wurden die Schichtanteile zu 80% W, 5% O, 6% C und 9% Ga ermittelt (Angaben in Atomprozent). Der spezifische Widerstand der Wolframdrähte ist im Bereich 150 ... 320 µWcm gemessen worden.
3
Mucke, S. "Herstellung von Nanometer-Strukturen mittels feinfokussiertem Ionenstrahl (FIB)". Forschungszentrum Rossendorf, 2004. https://hzdr.qucosa.de/id/qucosa%3A21721.
Testo completoAbstract (sommario):
Feinfokussierte Ionenstrahlen dienen in den Gebieten der Halbleiterindustrie und Materialforschung der Mikro- und Nanostrukturierung. Die vorliegende Arbeit beschäftigt sich mit den beiden Hauptanwendungen von fokussierten Ionenstrahlen, dem Materialabtrag und der ionenstrahlinduzierten Materialabscheidung. Dabei wird die hochauflösende Ionensäule CANION 31Z der Firma Orsay Physics mit Stromdichten von bis zu 10 A/cm2 und mit integriertem Gassystem eingesetzt. Es wird ausführlich auf Anwendungsbeispiele von Fokussierten Ionenstrahlsystemen im Bereich der Industrie und Forschung eingegangen. Schwerpunktmäßig wird die Abscheidung von Wolfram aus dem Precursorgas W(CO)6 (Wolframhexacarbonyl) auf Si und SiO2 als Substrat untersucht, mit dem Ziel, gut leitfähige Drähte (hier im Sinne von Leiterbahnen) mit minimalem Querschnitt herzustellen. Die Optimierung der Ionenstrahl-Parameter dieser Feinfokussierten Ionenstrahlanlage bezüglich der Abscheidung steht im Vordergrund. Dabei wird ein kurzer Einblick in die Theorie der Schichtentstehung beim Abscheidevorgang gegeben. Untersuchungen der erzeugten Strukturen entsprechend der Schichtqualität und der Strukturabmessungen werden erläutert und die Ergebnisse diskutiert. Es konnten Wolframdrähte mit einer Länge von 20 ... 100 µm, einer Breite von minimal 150 nm und einer Höhe von maximal 600 nm angefertigt werden. Die Zusammensetzung der Drähte in Abhängigkeit der Prozessparameter wurde mittels AES bestimmt. Im optimalen Fall wurden die Schichtanteile zu 80% W, 5% O, 6% C und 9% Ga ermittelt (Angaben in Atomprozent). Der spezifische Widerstand der Wolframdrähte ist im Bereich 150 ... 320 µWcm gemessen worden.
4
Claude, Jean-Benoît. "Etude des mécanismes de nanogravure par FIB-LMAIS". Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0445/document.
Testo completoAbstract (sommario):
Les problématiques liées à la diminution de la taille des dispositifs actuels amènent l’industrie à réfléchir à des techniques de gravure ayant des résolutions à l’échelle de l’atome. Dans ce contexte, les techniques de nanostructuration directes sont très bien adaptées et représentent un potentiel important pour un futur proche dans les laboratoires de recherches. Le projet sur lequel j’ai travaillé avait pour but de coupler dans un environnement Ultra-Vide (UHV), un Dual-Beam, composé d’un FIB (Faisceau d’Ions Focalisé) et d’un MEB (Microscope électronique à balayage) et un bâti d’épitaxie par jet moléculaire (MBE), technique ultime en termes de dépôt. Cet environnement UHV répond à la nécessité de propreté absolue des substrats et constitue un moyen pertinent de rendre fonctionnels les dispositifs ainsi élaborés dans des domaines aussi variés que la micro-nanoélectronique, l’optoélectronique, le photovoltaïque, la spintronique, la plasmonique, etc. La connexion sous UHV de la nanofabrication FIB à la croissance MBE représente une voie unique pour fabriquer des structures 3D en alternant des étapes gravure/dépôt. Parmi les différentes applications, nous avons choisi de nous focaliser sur nanostructures de silicium. Le principal challenge pour l’industrie microélectronique et pour les chercheurs est d’être capable de réaliser une optoélectronique entièrement intégrée à base de Si. Cela nécessite de convertir les matériaux à base de Si en absorbeur/émetteur efficaces de lumière. Une des pistes les plus prometteuses pour obtenir une bande interdite directe est de combiner les effets de la fonctionnalisation chimique et du confinement quantique dans les nano-objetsThe reduction of device sizes represents a major issue in microelectronic industry which motivates several teams of researchers to develop nanopatterning with atomic resolution. In this context, maskless nanostructuration techniques are well-adapted and have an important potential for the nearest future in labs and industry. The aim of the project I worked on is the connection in a Ultra-High-Vacuum (UHV) environment between a Dual-Beam, equipped with a FIB (Focused Ion Beam) and a SEM (Scanning Electron Microscopy) and a MBE (Molecular Beam Epitaxy) cluster, which is the highest-controlled deposition technique. The UHV environment is the solution for an absolute cleanliness and represents a relevant way to fabricate functionalized devices for micro-nanoelectronics, optoelectronics, photovoltaic, spintronic, plasmonic, etc… This UHV connection combining FIB nanostructuration and epitaxy growth technique provides a unique platform to elaborate tridimensional structures with milling/deposition steps. Among different applications, we decided to focus on silicon based nanostructures. Regarding silicon nanostructures. The main challenge for microelectronics industry and for the researchers in this field is the realization of optoelectronics devices fully integrated in silicon systems. This requires to convert silicon based materials into absorber/emitter of light. One of the most promising way to change the electronic structure and to get a direct bandgap is the combination of chemical functionalization and quantum confinement into silicon based nano-objects
5
Guellil, Imene. "Nano-fonctionnalisation par FIB haute résolution de silicium". Electronic Thesis or Diss., Aix-Marseille, 2022. http://www.theses.fr/2022AIXM0361.
Testo completoAbstract (sommario):
Le but de ce travail est de développer un processus d’élaboration de boîtes quantiques (QD) de silicium-germanium (SiGe) avec des compositions allant du Si au Ge pur, et permettant d’obtenir des QD semi-conductrices et de tailles suffisamment petites pour l’obtention de confinement quantique. Pour cela, nous avons utilisé une combinaison de différentes techniques : l’épitaxie par jets moléculaires, la lithographie ionique par faisceau d’ions focalisés (FIBL) et le démouillage solide hétérogène. Dans ce contexte, la finalité de cette recherche est d’une part de développer un FIB qui puisse être couplé à un bâti d’épitaxie par jets moléculaires sous ultra-vide et d’autre part de valider le FIB avec deux applications : des nanogravures pour l’auto-organisation des QD et des nano-implantations de Si et de Ge pour la création de défauts locaux émetteurs de lumière. Nous avons utilisé la FIBL avec des sources d’ions d’alliage métallique liquide (LMAIS) filtrées en énergie utilisant des ions non polluants (Si et Ge) dans des substrats issus de la microélectronique tels que des substrats de SiGe sur silicium-sur-isolant (SGOI). Les nano-gravures doivent être totalement dénuées de pollution et aux caractéristiques variables et parfaitement contrôlées (taille, densité, profondeur). La morphologie des nano-gravures obtenues est ensuite caractérisée in-situ par microscopie électronique à balayage (SEM), et la profondeur est déterminée par des caractérisations ex-situ par microscopie de force atomique (AFM). Les nano-gravures réalisées par FIBL ont été comparées d’une part aux gravures plasmas avec He et Ne et d’autre part aux gravures obtenues par lithographie électronique (EBL)The goal of this work is to develop a process for the elaboration of silicon-germanium (SiGe) quantum dots (QDs) with compositions ranging from Si to pure Ge, and allowing to obtain semiconducting QDs with sufficiently small sizes to obtain quantum confinement. For this purpose, we have used a combination of different techniques: molecular beam epitaxy, focused ion beam lithography (FIBL) and heterogeneous solid state dewetting. In this context, the aim of this research is on the one hand to develop a new FIB that can be coupled to the ultra-high vacuum molecular beam epitaxy growth chamber, and on the other hand to realize two applications: (i) nanopatterns for the self-organisation of Si and Ge QDs and (ii) nano-implantations of Si and Ge. We used FIBL with energy-filtered liquid metal alloy ion sources (LMAIS) using non-polluting ions (Si and Ge) for the milling of conventional microelectronic substrates such as SiGe on silicon-on-insulator (SGOI). The nanopatterns must be totally free of pollution and with variable and perfectly controlled characteristics (size, density, depth). The morphology of the nanopatterns is then characterized in-situ by scanning electron microscopy (SEM), and the depth is determined ex-situ by atomic force microscopy (AFM). The nanopatterns made by FIBL were compared on the one hand to plasma etchings with He and Ne and on the other hand to the etchings obtained by electronic lithography (EBL). Nanoimplantations of Si and Ge ions were realised in diamond and in ultra-thin SGOI for the fabrication of local defects
6
Claude, Jean-Benoît. "Etude des mécanismes de nanogravure par FIB-LMAIS". Electronic Thesis or Diss., Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0445.
Testo completoAbstract (sommario):
Les problématiques liées à la diminution de la taille des dispositifs actuels amènent l’industrie à réfléchir à des techniques de gravure ayant des résolutions à l’échelle de l’atome. Dans ce contexte, les techniques de nanostructuration directes sont très bien adaptées et représentent un potentiel important pour un futur proche dans les laboratoires de recherches. Le projet sur lequel j’ai travaillé avait pour but de coupler dans un environnement Ultra-Vide (UHV), un Dual-Beam, composé d’un FIB (Faisceau d’Ions Focalisé) et d’un MEB (Microscope électronique à balayage) et un bâti d’épitaxie par jet moléculaire (MBE), technique ultime en termes de dépôt. Cet environnement UHV répond à la nécessité de propreté absolue des substrats et constitue un moyen pertinent de rendre fonctionnels les dispositifs ainsi élaborés dans des domaines aussi variés que la micro-nanoélectronique, l’optoélectronique, le photovoltaïque, la spintronique, la plasmonique, etc. La connexion sous UHV de la nanofabrication FIB à la croissance MBE représente une voie unique pour fabriquer des structures 3D en alternant des étapes gravure/dépôt. Parmi les différentes applications, nous avons choisi de nous focaliser sur nanostructures de silicium. Le principal challenge pour l’industrie microélectronique et pour les chercheurs est d’être capable de réaliser une optoélectronique entièrement intégrée à base de Si. Cela nécessite de convertir les matériaux à base de Si en absorbeur/émetteur efficaces de lumière. Une des pistes les plus prometteuses pour obtenir une bande interdite directe est de combiner les effets de la fonctionnalisation chimique et du confinement quantique dans les nano-objetsThe reduction of device sizes represents a major issue in microelectronic industry which motivates several teams of researchers to develop nanopatterning with atomic resolution. In this context, maskless nanostructuration techniques are well-adapted and have an important potential for the nearest future in labs and industry. The aim of the project I worked on is the connection in a Ultra-High-Vacuum (UHV) environment between a Dual-Beam, equipped with a FIB (Focused Ion Beam) and a SEM (Scanning Electron Microscopy) and a MBE (Molecular Beam Epitaxy) cluster, which is the highest-controlled deposition technique. The UHV environment is the solution for an absolute cleanliness and represents a relevant way to fabricate functionalized devices for micro-nanoelectronics, optoelectronics, photovoltaic, spintronic, plasmonic, etc… This UHV connection combining FIB nanostructuration and epitaxy growth technique provides a unique platform to elaborate tridimensional structures with milling/deposition steps. Among different applications, we decided to focus on silicon based nanostructures. Regarding silicon nanostructures. The main challenge for microelectronics industry and for the researchers in this field is the realization of optoelectronics devices fully integrated in silicon systems. This requires to convert silicon based materials into absorber/emitter of light. One of the most promising way to change the electronic structure and to get a direct bandgap is the combination of chemical functionalization and quantum confinement into silicon based nano-objects
7
Rose, Philip David. "High-resolution in situ FIB lithography of MBE GaAs". Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624802.
Testo completo
8
Konečný, Martin. "Aplikace KPM na povrchu grafén/Si modifikovaném metodou FIB". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230836.
Testo completoAbstract (sommario):
This diploma thesis is focused on the application of Kelvin probe microscopy on graphene fabricated by the chemical vapour deposition. The theoretical part of the thesis deals with basic principles of Kelvin force microscopy and focus ion beam. Further, basic properties of graphene and its possible fabrication methods are discussed. The experimental part is focused on the surface potential measurements on graphene membranes fabricated on the substrate modified by focus ion beam. Finally, atomic force microscope lithography was used for nanopatterning of graphene sheets.
9
ElFallagh, Fathi Ali. "3D Analysis of Indentation Damage by FIB tomography and TEM". Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500111.
Testo completo
10
Houel, Arnaud. "Ecriture directe de motifs nanométriques assistée par STM et FIB". Aix-Marseille 2, 2002. http://www.theses.fr/2002AIX22063.
Testo completo
11
Moseley, Richard William. "Focused ion beam fabricated non-equilibrium superconducting devices". Thesis, University of Cambridge, 2000. https://www.repository.cam.ac.uk/handle/1810/183624.
Testo completoAbstract (sommario):
The developments over the last decade in Focused Ion Beam (FIB) instrument technology have reached a point where there is sufficient control of an ion beam to make cuts, trenches, and other shapes in a sample on a scale of tens of nanometers. This work concentrates on the use of an FIB instrument for making superconducting devices. It is shown for the first time that planar-bridge (Nb/Cu/Nb) Superconductor/Normalmetal/Superconductor (SNS) junctions can be reliably fabricated using a standard FIB instrument. This is demonstrated by the responses of junctions to microwaves and magnetic fields; the junctions display the appropriate Josephson behaviour demanded by current technological applications. In addition, the reproducibility in junction behaviour (the variation of critical current is approximately 10%) is the best so far observed for this type of junction. The SNS junction fabrication method has been successfully extended for making high-density SNS junction arrays, dc-SQUIDs, and related devices. A simple model is devised to explain the normal-state resistance and critical current of a junction. The model is based on the geometry of a junction as defined by the FIB instrument and the film deposition. The model is mostly successful in qualitatively explaining many of the geometrical factors that affect the electrical properties of the junction. Nb/Cu/Nb junction series arrays, made using an FIB instrument, are also successfully fabricated. The yield of the junctions forming small arrays is found to be similar to the yield of single junctions. For the series arrays studied here, new observations have been made: the electrical properties of an array have been found to be dependent on the spacing of the junctions and the number of junctions in the array. This work also investigates the thermal properties of SNS and micron-scale superconductor/insulator/normal-metal junction based devices for use in bolometer device based applications. It is shown that self-heating raises the temperature of the junctions significantly above their operating temperatures. For a device sitting on a low thermally conductive membrane, it is found that the effects of heating, or cooling, in the junctions are exaggerated.
12
Lenk, Andreas. "Quantitative Messung von Dotiergebieten in FIB-präparierten Silizium-Halbleiterbauelementen mittels Elektronenholographie". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1227281033997-66534.
Testo completoAbstract (sommario):
Das Einbringen von Dotierstoffen in das Substratmaterial ist einer der wichtigsten Teilprozesse in der Halbleiterindustrie. Größe, Lage und Konzentration elektrisch aktiver Dotiergebiete bestimmen wesentlich die Eigenschaften der mikroelektronischen Basisbauelemente und damit die Funktionalität der Endprodukte. Die kontinuierliche Verkleinerung dieser Bauelemente zieht steigende Anforderungen an die Präzision bei ihrer Herstellung nach sich. Analyseverfahren, mit denen die genannten Kenngrößen gemessen werden können, sind aus diesem Grund von hoher Bedeutung. Elektronenholographie ist eine dafür prinzipiell geeignete Messmethode, da sie eine zweidimensionale Vermessung der durch die Dotanden veränderten Potentialstruktur des Halbleiters in der geforderten Ortsauflösung von wenigen nm erlaubt. Ein Teil dieser Arbeit befasst sich mit der Optimierung der für die holographische Untersuchung wichtigen Parameter. Zu diesem Zweck werden sowohl präparative Aspekte wie geeignete Probendicke und Struktur der Proben als auch messtechnische Aspekte wie kohärente Beleuchtung und TEM-Parameter diskutiert. Während sich der Hauptteil der Arbeit mit den dabei gewonnenen wissenschaftlichen Erkenntnissen befasst, werden im Anhang die bei Präparation und Messung wichtigen Details ausführlich beschrieben. Ein wesentliches Problem bei der elektronenholographischen Messung stellt die Präparation der Objekte für die Untersuchung im TEM dar. Die einzige sinnvolle Möglichkeit für eine industrielle Anwendung ist die Zielpräparation mit dem fokussierten Ionenstrahl („FIB“), da keine andere Methode vergleichbar effizient arbeitet. Leider wird bei dieser Art von Präparation die Probe von der Oberfläche bis in eine gewisse Tiefe sowohl strukturell als auch elektrisch verändert. Diese Artefakte beeinflussen das Ergebnis der hochsensiblen holographischen Messung. Um die gewonnenen Daten dennoch verlässlich quantitativ auswerten zu können, muss klar zwischen ursprünglichen Objekteigenschaften und präparativ induzierten Schädigungen unterschieden werden. Um dieses Ziel zu erreichen, wurden durch die FIB-Präparation hervorgerufene Schädigungen der Probe systematisch analysiert. Mit Hilfe von SIMS konnte die Tiefenverteilung des beim Ionenschneiden eingedrungenen Fremdmaterials gemessen werden. Es wurden Querschnitte von FIB-Proben durch konventionelle, holographische sowie holographisch-tomographische Abbildung im TEM an einer eigens dafür entwickelten nadelförmigen Probengeometrie untersucht. Dabei wurden die entstandenen strukturellen und elektrischen Veränderungen beobachtet und quantitativ charakterisiert. Der Einsatz von Tomographie erlaubte schließlich die Messung der Potentialverteilung im Inneren der Nadeln ohne eine Verfälschung durch Projektionseffekte. Es wurde gezeigt, dass die über die Schädigungen gewonnenen Erkenntnisse für eine Korrektur der holographischen Daten genutzt werden können. Dazu wurden entsprechende Untersuchungen an verschiedenen Bauelementen aus der Halbleiterindustrie durchgeführt. Die korrigierten Ergebnisse wurden dabei stets mit den theoretischen Erwartungen verglichen.
13
Zorzos, Anthony Nicholas. "The use of ionic liquid ion sources (ILIS) in FIB applications". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/51647.
Testo completoAbstract (sommario):
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2009.Includes bibliographical references (leaves 82-86).
A new monoenergetic, high-brightness ion source can be constructed using an arrangement similar to liquid metal ion sources (LMIS) by substituting the liquid metal with an ionic liquid, or room temperature molten salt. Ion beams produced by these ionic liquid ion sources (ILIS) have energy deficits and distributions that closely resemble their metallic counterparts, with the exception that, if needed, they can be stably operated at current levels as low as a few nA. ILIS sources are here presented as having two further key advantages: (1) the ability to obtain both positive and negative ion beams, and (2) the ability to produce very diverse molecular ions in terms of their masses, compositions and properties, due to the fact that the number of available ionic liquids is large. In this thesis an overview of ILIS sources is presented, as well as preliminary results of their performance in a FIB column.
by Anthony Nicholas Zorzos.
S.M.
14
Ruiz, Élise. "Nanostructuration par FIB filtrée pour l'élaboration de nanostructures semi-conductrices organisées". Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4326/document.
Testo completoAbstract (sommario):
Les nanofils (NFs), de par leur propriétés opto et nanoélectroniques sont devenus des éléments indispensable à la fabrication des dispositifs de la nanoélectronique. Le problème principal reste la reproductibilité en terme de densité de NFs, de diamètre... Cette thèse a pour but de développer grâce à la technologie FIB, un procédé permettant l'élaboration de NFs organisés et homogène en tailleDue to their ease of fabrication and unique physical properties, semiconductor nanowires (NWs) have been proposed as building blocks for new nanoelectronic and photonic devices. Various processes have been developed to obtain large density of ultra-small NWs but naturally forms nanowires often lack reproducibility. We propose to develop a bottom-up (B-U)processes which is based on naturally formed NWs grown on a patterned substrate resulting from self-assembly of metallic clusters or exposition to a focused ion beam (FIB). The major goal consist to obtain organized and homogeneous NWs
15
Velichko, Alexandra. "Quantitative 3D characterization of graphite morphologiesin cast iron using FIB microstructure tomography". Aachen Shaker, 2008. http://d-nb.info/992480035/04.
Testo completo
16
Richter, Mirja. "Croissance par EJM à boîtes quantiques sur des couches localement dopées par FIB". Nice, 2007. http://www.theses.fr/2007NICE4086.
Testo completoAbstract (sommario):
L’objet de ce travail fut d’étudier et de modifier la structure des niveaux énergétiques de boîtes quantiques InAs par croissance de différentes couches de confinement supérieures. L’effet de telles couches faites de (In,Ga)As, sur la structure de niveaux de boîtes quantiques InAs auto-assemblées, a été étudié par spectroscopie de capacité vs tension. Par rapport à l’emploi du GaAs, un décalage vers le rouge de l’émission du niveau fondamental a été observé. Il est montré que ce décalage provient en grande partie des états de la bande de conduction ? Avec un confinement fait de (InGa)(As,N), la longueur d’onde d’émission a pu être étendue jusqu’à1,52 μm. Une émission de haute qualité est obtenue après recuit thermique rapide, et ce jusqu’à une longueur d’onde de 1,45 μm. Par ailleurs, ces boîtes quantiques ont été intégrées au sein d’une diode electro-luminescente tout nouvellement développée. Les dimensions de la région active y ont été réduites par écriture isolante à l’aide de faisceaux d’ions focalisés, afin d’obtenir l’électroluminescence provenant de quelques boîtes quantiques seulement. Ce travail constitue une vers l’obtention de l’émission de photons uniques aux longueurs utilisées en télécommunications par fibres optiquesThe aim of this work was to study and alter the energetic level structure of self-assembled InAs quantum dots by overgrowth with different cap layers. The influence of (In,Ga)As cap layers on the level structure of self-assembled InAs quantum dots was studied by capacitance-voltage spectroscopy. The red shift of the ground state emission as compared to GaAs capping was found to originate mainly from the conduction band states. With (In,Ga)(As,N) capping, emission up to 1,52 μm was demonstrated. After rapid thermal annealing, highest quality emission was found up to 1. 45 μm. Additionally, InAs quantum dots were integrated into a newly developed light emitting diode whose active region was reduced by insulation writing with focused ion beams to achieve electroluminescence from few quantum dots only. Altogether, first steps were taken towards single photon emission at the most efficient telecommunication wavelengths
17
Prestigiacomo, Morgane. "Fabrication et étude de structures sub-microniques déposées par faisceau d'ions focalisés (FIB)". Aix-Marseille 2, 2005. http://www.theses.fr/2005AIX22051.
Testo completo
18
Yuan, Hui. "3D morphological and crystallographic analysis of materials with a Focused Ion Beam (FIB)". Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0134/document.
Testo completoAbstract (sommario):
L’objectif principal de ce travail est d’optimise la tomographie par coupe sériée dans un microscope ‘FIB’, en utilisant soit l’imagerie électronique du microscope à balayage (tomographie FIB-MEB), soit la diffraction des électrons rétrodiffusés (tomographie dite EBSD 3D). Dans les 2 cas, des couches successives de l’objet d’étude sont abrasées à l’aide du faisceau ionique, et les images MEB ou EBSD ainsi acquises séquentiellement sont utilisées pour reconstruire le volume du matériau. A cause de différentes sources de perturbation incontrôlées, des dérives sont généralement présentes durant l'acquisition en tomographie FIB-MEB. Nous avons ainsi développé une procédure in situ de correction des dérives afin de garder automatiquement la zone d'intérêt (ROI) dans le champ de vue. Afin de reconstruction le volume exploré, un alignement post-mortem aussi précis que possible est requis. Les méthodes actuelles utilisant la corrélation-croisée, pour robuste que soit cette technique numérique, présente de sévères limitations car il est difficile, sinon parfois impossible de se fier à une référence absolue. Ceci a été démontré par des expériences spécifiques ; nous proposons ainsi 2 méthodes alternatives qui permettent un bon alignement. Concernant la tomographie EBSD 3D, les difficultés techniques liées au pilotage de la sonde ionique pour l'abrasion précise et au repositionnement géométrique correct de l’échantillon entre les positions d'abrasion et d’EBSD conduisent à une limitation importante de la résolution spatiale avec les systèmes commerciaux (environ 50 nm)3. L’EBSD 3D souffre par ailleurs de limites théoriques (grand volume d'interaction électrons-solide et effets d'abrasion. Une nouvelle approche, qui couple l'imagerie MEB de bonne résolution en basse tension, et la cartographie d'orientation cristalline en EBSD avec des tensions élevées de MEB est proposée. Elle a nécessité le développement de scripts informatiques permettant de piloter à la fois les opérations d’abrasion par FIB et l’acquisition des images MEB et des cartes EBSD. L’intérêt et la faisabilité de notre approche est démontrée sur un cas concret (superalliage de nickel). En dernier lieu, s’agissant de cartographie d’orientation cristalline, une méthode alternative à l’EBSD a été testée, qui repose sur l’influence des effets de canalisation (ions ou électrons) sur les contrastes en imagerie d’électrons secondaires. Cette méthode corrèle à des simulations la variation d’intensité de chaque grain dans une série d’images expérimentales obtenues en inclinant et/ou tournant l’échantillon sous le faisceau primaire. Là encore, la méthode est testée sur un cas réel (polycritsal de TiN) et montre, par comparaison avec une cartographie EBSD, une désorientation maximale d'environ 4° pour les angles d’Euler. Les perspectives d’application de cette approche, potentiellement beaucoup plus rapide que l’EBSD, sont évoquéesThe aim of current work is to optimize the serial-sectioning based tomography in a dual-beam focused ion beam (FIB) microscope, either by imaging in scanning electron microscopy (so-called FIB-SEM tomography), or by electron backscatter diffraction (so-called 3D-EBSD tomography). In both two cases, successive layers of studying object are eroded with the help of ion beam, and sequentially acquired SEM or EBSD images are utilized to reconstruct material volume. Because of different uncontrolled disruptions, drifts are generally presented during the acquisition of FIB-SEM tomography. We have developed thus a live drift correction procedure to keep automatically the region of interest (ROI) in the field of view. For the reconstruction of investigated volume, a highly precise post-mortem alignment is desired. Current methods using the cross-correlation, expected to be robust as this digital technique, show severe limitations as it is difficult, even impossible sometimes to trust an absolute reference. This has been demonstrated by specially-prepared experiments; we suggest therefore two alternative methods, which allow good-quality alignment and lie respectively on obtaining the surface topography by a stereoscopic approach, independent of the acquisition of FIB-SEM tomography, and realisation of a crossed ‘hole’ thanks to the ion beam. As for 3D-EBSD tomography, technical problems, linked to the driving the ion beam for accurate machining and correct geometrical repositioning of the sample between milling and EBSD position, lead to an important limitation of spatial resolution in commercial softwares (~ 50 nm)3. Moreover, 3D EBSD suffers from theoretical limits (large electron-solid interaction volume for EBSD and FIB milling effects), and seems so fastidious because of very long time to implement. A new approach, coupling SEM imaging of good resolution (a few nanometres for X and Y directions) at low SEM voltage and crystal orientation mapping with EBSD at high SEM voltage, is proposed. This method requested the development of computer scripts, which allow to drive the milling of FIB, the acquisition of SEM images and EBSD maps. The interest and feasibility of our approaches are demonstrated by a concrete case (nickel super-alloy). Finally, as regards crystal orientation mapping, an alternative way to EBSD has been tested; which works on the influence of channelling effects (ions or electrons) on the imaging contrast of secondary electrons. This new method correlates the simulations with the intensity variation of each grain within an experimental image series obtained by tilting and/or rotating the sample under the primary beam. This routine is applied again on a real case (polycrystal TiN), and shows a max misorientation of about 4° for Euler angles, compared to an EBSD map. The application perspectives of this approach, potentially faster than EBSD, are also evoked
19
Parasuraman, Jayalakshmi. "Vers des métamatériaux thermoélectriques à base de super-réseaux verticaux : principes et verrous technologiques". Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1092/document.
Testo completoAbstract (sommario):
Les méta-matériaux offrent la possibilité d'obtenir des propriétés physiques nettement améliorées en comparaison avec celles des matériaux naturels. Dans ce travail, nous explorons une nouvelle variété de métamatériaux thermoélectriques à base de micro-et nano-structuration du silicium, sous la forme de super-réseaux verticaux, avec comme visée applicative la récupération d'énergie thermique ainsi que le refroidissement. En outre, nous focalisons nos efforts sur une méthodologie expérimentale permettant la réalisation de ces matériaux par des moyens simples et peu coûteux. La première partie de cette thèse sert d'introduction aux phénomènes thermiques qui constituent la base de la conduction électrique et de la dissipation de chaleur dans les nanostructures, respectivement par émission thermo-ionique et par la diffusion de phonons. Cette partie détaille également les principes et résultats de caractérisation thermique à l'aide des méthodes 3ω et 2ω. La deuxième partie de cette thèse décrit les approches de micro- nanostructuration descendante « top-down » et ascendante « bottom-up », en vue de la fabrication de super-réseaux nanométriques sur du silicium mono-cristallin. La nouvelle architecture verticale proposée soulève des défis technologiques qui sont traités à travers l'exploration de techniques expérimentales originales pour produire, d'une manière efficace et sur de grandes surfaces, des structures submicroniques à fort facteur de forme. Ces techniques comprennent l'utilisation de motifs résultant de lithographie traditionnelle combinée à l'extrusion pour en produire des structures volumiques. En outre, l'utilisation de nanofibres et de diblocs copolymères comme nano-motifs géométriques sont également présentés pour nous rapprocher davantage de l'objectif ultime du projetMetamaterials offer the benefit of obtaining improved physical properties over natural materials. In this work, we explore a new variety of thermoelectric metamaterials based on silicon micro- and nano- structuration, in the form of vertical superlattices for use in energy-related applications. Additionally, we focus on a route towards fabricating these materials using simple and low-cost means compared to prior attempts. The first part of this thesis serves as an introduction to the thermal phenomena which form the basis for electrical conduction and heat dissipation by thermionic emission and phonon scattering at the nanoscale. These principles forms the crux of the device. This section also details the characterization principles and results using the 3ω and 2ω methods for thermal measurement. The second part of this thesis describes both top-down and bottom-up approaches towards fabricating nanoscale superlattices from single-crystalline silicon. The novel proposed vertical architecture raised technological challenges that were tackled through the exploration of original experimental techniques for producing high aspect ratio (HAR) structures in an effective manner and over large surface areas. These techniques include the use of traditional lithography patterning and subsequent extrusion of volumic structures. Additionally, the use of nanofibers and diblock copolymers as templates for further etching of HAR silicon nanostructures are also presented to bring us closer to the ultimate goal of the project
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Williams, Robert Enon Alexander. "Development and Application of Advanced Electron Microscopy Characterization Techniques to Binary Titanium – Molybedenum Alloys". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275411755.
Testo completo
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Liu, Yang. "‘Tri-3D’ electron microscopy tomography by FIB, SEM and TEM : Application to polymer nanocomposites". Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0076/document.
Testo completoAbstract (sommario):
Ce travail a porté sur la caractérisation et la quantification en 3D de la répartition de charges de différents types (nanoparticules, nanotubes, etc.) dans des matrices polymères. Nous nous focalisons sur les techniques de tomographie en microscopie électronique. Une approche multiple en tomographie électronique a été réalisée : la tomographie en FIB/MEB (faisceau d’ions focalisé/microscope électronique à balayage), la tomographie en MEB et la tomographie en MET (microscope électronique en transmission). Les nanocomposites polymère sont généralement élaborés aux fins d’améliorer les propriétés physiques (mécanique, électrique, etc.) du matériau polymère constituant la matrice, grâce à une addition contrôlée de charges nanométriques. La caractérisation de tels matériaux, et l’établissement de corrélations précises entre la microstructure et les propriétés d’usage, requièrent une approche tri-dimensionnelle. En raison de la taille nanométrique des charges, la microscopie électronique est incontournable. Deux systèmes de nanocomposite polymère ont été étudiés par une approche multiple de tomographie électronique : P(BuA-stat-S)/MWNTs (copolymère statistique poly (styrène-co-acrylate de butyl) renforcé par des nanotubes de carbone multi-parois), et P(BuA-stat-MMA)/SiO2 (copolymère statistique poly(butyl acrylate-co-methyl methacrylate) renforcé par des nanoparticules de silice). Par combinaison de divers techniques, la caractérisation et la quantification des nanocharges ont été possibles. En particulier, la taille, la fraction volumique et la distribution des charges ont été mesurées. Cette étude a ainsi fourni des informations en 3D qui contribuent à mieux comprendre les propriétés des nanocomposites. Une attention particulière a été portée aux artefacts et causes d’erreur possibles durant l’étape de traitement 3D. Nous avons également essayé de comparer les différentes techniques utilisées du point de vue de leurs avantages et inconvénients respectifs, en dégageant des possibilités d’amélioration futureThis work is focused on the characterization and quantification of the 3D distribution of different types of fillers (nanoparticles, nanotubes, etc.) in polymer matrices. We have essentially used tomography techniques in electron microscopy. Multiple approaches to electron tomography were performed: FIB-SEM (focused ion beam/scanning electron microscope) tomography, SEM tomography and TEM (transmission electron microscope) tomography. Polymer nanocomposites are basically synthesized in order to improve the physical properties (mechanical, electric, etc.) of the pure polymer constituting the matrix, by a controlled addition of fillers at the nanoscale. The characterization of such materials and the establishment of accurate correlations between the microstructure and the modified properties require a three-dimensional approach. According to the nanometric size of the fillers, electron microscopy techniques are needed. Two systems of polymer nanocomposites have been studied by multiple electron tomography approaches: P(BuA-stat-S)/MWNTs (statistical copolymer poly(styrene-co-butyl acrylate) reinforced by multi-walled carbon nanotubes) and P(BuA-stat-MMA)/SiO2 (statistical copolymer poly(butyl acrylate-co-methyl methacrylate) reinforced by silica nanoparticles). By combining various techniques, the characterization and the quantification of nanofillers were possible. In particular, statistics about size, distribution and volume fraction of the fillers were measured. This study has then provided 3D information, which contributes to a better understanding of properties of the nanocomposites. Attention has been paid to analyze carefully original data, and artifacts and causes of errors or inaccuracy were considered in the 3D treatments. We also attempted to compare benefits and drawbacks of all techniques employed in this study, and perspectives for future improvements have been proposed
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Beere, H. E. "Selective area growth of III-V semiconductor compounds using Ga+ FIB deposition during MBE growth". Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596523.
Testo completoAbstract (sommario):
Selective area growth of III-V semiconductor compounds using molecular beam epitaxy (MBE) has been envisaged as an in situ fabrication method for integrated circuits on a nanometer scale. However, conventional selective area growth techniques using MBE are limited to only two dimensional, template-like, pattering of the epilayer. The work presented in this dissertation describes the selective area growth of AlGaAs based structures using a Ga+ focused ion beam (FIB) as one of the group III matrix element sources in a MBE growth chamber. Since stoichiometric epitaxy of a III-V semiconductor compound can be achieved with an excess supply of the group V element, supplying the Ga matrix element as a FIB, under standard MBE growth conditions, was shown to facilitate a maskless, in situ, lateral selective area growth technique for GaAs. Consequently, this FIB-MBE growth technique, FIMBE, has the potential of exploiting the precise control over the elemental composition afforded by MBE in the growth (z) direction with the high spatial resolution of FIB technology in the lateral (xy) plane. Moreover, it offers the unique facility of growing fully integrated three-dimensional structures into one as-grown epilayer structure. The necessary modifications required to a standard FIB column and MBE growth chamber to fully exploit the combination of these two technologies, along with the operational performance of the fully integrated FIMBE growth system are presented. A study of the effect of incident ion energy (Eion) on the film growth rate identified two growth rate limiting processes; (i) the inherent properties of the Ga+ FIB (Eion <25eV) and (ii) material sputtering from the growing GaAs film (Eion>100eV). However, a systematic reduction in the surface roughness of the FIMBE grown GaAs films was observed with increasing incident ion energy.
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Velichko, Alexandra [Verfasser]. "Quantitative 3D Characterization of Graphite Morphologies in Cast Iron using FIB Microstructure Tomography / Alexandra Velichko". Aachen : Shaker, 2009. http://d-nb.info/1161310541/34.
Testo completo
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Sazio, Pier-John Anthony. "In situ fabrication of 3-D patterned semiconductor structures using FIB doping during MBE growth". Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624877.
Testo completo
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Bossard, Carine. "Etude de nouveaux partenaires protéiques du facteur de croissance fibroblastique 2 humain : translokine et FIB". Toulouse 3, 2003. http://www.theses.fr/2003TOU30062.
Testo completoAbstract (sommario):
Le FGF-2 est un facteur de croissance pléiotropique, connu comme l'un des principaux facteurs angiogéniques. Cinq isoformes protéiques de 18 - 22 - 22,5 - 24 et 34 kDa sont générées par un processus d'initiation alternative de la traduction. Ces isoformes ont des localisations subcellulaires distinctes et peuvent agir de manière paracrine, autocrine ou intracrine. Cependant, les mécanismes moléculaires mis en jeu dans l'activité intracellulaire du FGF-2 ne sont pas connus. Nous avons donc cherché à identifier des partenaires protéiques du FGF-2 par la technique du double-hybride. Nous avons ainsi isolé trois ADNc humains, codant pour trois protéines inconnues : une protéine nucléaire la FIF (FGF-2 Interacting Factor), une protéine cytoplasmique la Translokine, et un fragment de protéine sécrétée Fib. Mon projet de thèse a consisté à étudier la fonction biologique de ces deux dernières cibles du FGF-2 et à comprendre l'intérêt de leur interaction avec le FGF-2. Ainsi, nous avons pu montrer d'une part que la Translokine était impliquée dans la translocation nucléaire du FGF-2, étape cruciale pour l'activité mitogénique du facteur de croissance, et d'autre part que la Fib représentait un nouveau facteur anti-angiogéniques aussi efficace que l'endostatineFGF-2 is a growth factor with pleiotropic activities, known as a major angiogenic factor. Five FGF-2 isoforms of 18, 22, 22. 5, 24, and 34 kDa, synthesized through an alternative translational initiation process, are localized to different compartments in the cell or exported to the extracellular space. FGF-2 can thus act in a paracrine, autocrine or intracrine way. However, the molecular basis of its intracellular activities are poorly understood. In order to better understand the molecular mechanisms underlying these activities, we used the two-hybrid system to identify new potential FGF-2 targets. Several selected clones encoded three unknown polypeptides which interact specifically with FGF-2 : a nuclear protein FIF, a cytoplasmic protein Translokin, and a fragment of a secreted protein Fib. My thesis project consisted in characterizing the function of Translokin and Fib and understanding their interaction with FGF-2. We have shown that Translokin is involved in the nuclear translocation of FGF-2, a process which is necessary for the mitogenic activity of the growth factor, and that Fib is a novel antiangiogenic factor as efficient as endostatin
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He, Shuai. "Investigation of Cathode/Electrolyte Interfaces in Solid Oxide Fuel Cells by using FIB-STEM Techniques". Thesis, Curtin University, 2019. http://hdl.handle.net/20.500.11937/76137.
Testo completoAbstract (sommario):
The evolution of cathode/electrolyte interface in solid oxide fuel cells (SOFCs) during operation is an important indicator for evaluating the overall performance of a cell. In this thesis, the most important and typical interfaces were studied in great details under wide range of SOFC operation conditions using combined focused ion beam-scanning transmission electron microscopy techniques. The results clearly demonstrate the dynamic relationship between interface, segregation, and performance of cathode materials for fuel cells.
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Rathod, Pankaj Ramniklal. "Development of micro/nano textured tools by fib and their performance evaluation through machinability studies". Thesis, IIT Delhi, 2016. http://localhost:8080/iit/handle/2074/6976.
Testo completo
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Ghosh, Joydeep. "Fabrication of laterally stacked spin devices by semiconductor processing". Master's thesis, Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-91779.
Testo completoAbstract (sommario):
This work presents a new approach of fabricating arrays of electrodes, separated by sub-micrometer gaps allowing the systematic investigation of electric properties of organic semiconductors. The laterally stacked devices are fabricated by using a trench isolation technique for separating different electrical potentials, as it is known for micromachining technologies like Single Crystal Reactive Ion Etching and Metallization (SCREAM). The essential part of this process is the patterning of sub-micrometer trenches onto the silicon substrate in a single lithographic step. Afterwards, the trenches are refilled by SiO2 to allow the precise tuning of the electrode separation gap. The metal electrodes are formed via magnetron sputtering. This technological approach allows us to fabricate device structures with a transport channel length in the range of 100-250 nm by conventional photolithography. In this experiment, three different metals like Au, Co, and Ni were used as the electrode materials, while copper phthalocyanine, being deposited by thermal evaporation in high vacuum, was employed as the organic semiconductor under evaluation. The final aim has been study of spin transport through the organic channel in varied geometry.
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Bourdelle, Franck. "Thermobaromètrie des phylloscilicates dans les séries naturelles : conditions de la diagénèse et du métamorphisme de bas degré". Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00616543.
Testo completoAbstract (sommario):
Les illites et les chlorites sont des minéraux ubiquistes dans la plupart des roches diagénétiques. Leurs compositions chimiques dépendent des conditions physiques subies (pression, P ; température, T) et de la composition de l'encaissant (e.g. Vidal et al., 1999 ; Parra et al., 2002a, 2002b). Ces minéraux peuvent donc potentiellement être de très bons marqueurs de l'histoire de l'enfouissement, et sont à la base de nombreuses méthodes empiriques ou thermodynamiques d'estimation des conditions P-T.Une compilation de données naturelles et la comparaison des thermobaromètres existants ont permis d'établir leurs limitations respectives. Pour s'en affranchir, un nouveau modèle ordonné de solution solide pour les chlorites a été développé, qui rend compte des forts contenus en silicium observés dans les chlorites naturelles de basses températures. La calibration de ce nouveau thermobaromètre sur des domaines géologiques variés de BT-BP a été testée sur des analyses de chlorites naturelles de la Gulf Coast (Texas) au pic de température (où les données P-T ont été mesurées in situ) et montre d'excellents résultats. Concernant les illites, le modèle thermodynamique le plus abouti (Dubacq et al., 2010) a également été testé de manière à estimer sa précision. L'étude a été complétée par la quantification de l'influence du fer ferrique. Les analyses chimiques utilisées ont été obtenues grâce à un protocole analytique à haute résolution spatiale. Alliant FIB et MET-EDS, ce protocole a permis une étude microtexturale et chimique fine des chlorites et des illites. Il en ressort que ces minéraux possèdent une diversité intracristalline dans leurs compositions et que la zonation chimique résultante apparaît comme une potentielle source d'erreurs dans la calibration des thermobaromètres, tout en permettant d'envisager la notion d'équilibre à l'échelle locale.Cette approche a été utilisée pour quantifier les trajets P-T d'unités géologiques des Alpes de Glarus. Ces résultats, comparés à ceux obtenus avec des méthodes thermobarométriques conventionnelles, donnent une bonne image des processus d'enfouissement et d'exhumation des roches de basse température. Ainsi, il apparaît que chaque composition enregistre une portion du chemin P-T rétrograde. D'une manière générale, chaque zone d'un même cristal renvoie à une partie de l'histoire de la roche.
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Sandvold, Marianne. "Technical Aspects of Ion Milling and Electron Imaging of Epoxy Embedded Samples for FIB/SEM Tomography". Thesis, Norges Teknisk-Naturvitenskaplige Universitet, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20916.
Testo completoAbstract (sommario):
FIB/SEM tomography is a relatively new imaging technique for 3D investigation of biological tissue. It uses a dualbeam FIB/SEM instrument to alternately image a sample surface with an electron beam and mill off successive slices with an ion beam, collecting a series of images representing the investigated volume. This technique was employed to study alumina nanoparticles, brain tissue and tissue engineered cartilage embedded in epoxy. Hydrocarbon deposition of contamination layers as well as suboptimal sample geometry, were shown to be issues for imaging experiments. It was important to ensure that sample blocks were cut smoothly, and that the material of interest was concentrated at an edge. The alumina nanoparticle sample was used as a model specimen to investigate the volume of origin of signals detected for image formation at different acceleration voltages. This was shown to have a reasonable correspondance with Monte Carlo simulation results. Imaging and Slice and View experiments on the biological samples showed that FIB/SEM tomography can resolve structures below 10nm in size, and that detailed 3D models from properly stained tissue are obtainable. In summary FIB/SEM tomography constitutes a valuable 3D imaging technique for biological samples.
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Ervik, Ken Roger. "Applikasjon av fokusert ionestråle (FIB) og skanning elektronmikroskop (SEM) for karakterisering av vev, celler og biomaterialer". Thesis, Norges Teknisk-Naturvitenskaplige Universitet, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21046.
Testo completoAbstract (sommario):
Dette prosjektet har den intensjon å utforske karakteriseringsmuligheter med fokusert ionestråle (FIB) kombinert med skanning elektronmikroskop (SEM). Aspekter ved prøvepreparering, bilde prosessering har blitt diskutert. Oppnåelse inkluderer ervervelse av 3D data fra to ulike materialer; Strukturinformasjon av biopolymer alginate hydrogel kuler (kritisk punkt tørket). Fra dette materialet er det blitt ervervet bildestabler med oppløsning av 25 nm (skive tykkelse) i z-retning. Det andre materialet er celler (macrophager fra mus) omsluttet i epoxy. Fra denne type materiale er det blitt ervervet bildestabler med 30 og 40 nm mellom hver skive, hvor cellulære strukturer og organeller kan tydelig bli sett. En 3D-rekonstruksjon av cellevevet er også gjort.
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Pereira, Edmilson Peralva. "Estudo de caso: impacto do PROUNI nos alunos egressos do Centro Universitário Estácio/FIB Salvador-Ba". Universidade Catolica de Salvador, 2013. http://ri.ucsal.br:8080/jspui/handle/123456730/143.
Testo completoAbstract (sommario):
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O Programa Universidade para Todos (ProUni) surgiu como política pública que garante o ingresso e permanência de jovens sem recursos em universidades particulares. O Programa nasceu por iniciativa do Governo Federal e sua implantação se deu em diferentes faculdades, universidades e centros universitários do Brasil, a partir de 2005. Estuda-se o caso dos alunos egressos beneficiados do Centro Universitário Estácio/FIB, de Salvador. Como amostragem, foram entrevistados os alunos que foram beneficiados com o ProUni em 2005, grande parte formados a partir de 2008 e que já integram o mercado de trabalho. Alguns apontaram o Programa como benéfico, outros apontaram algumas poucas deficiências e, dentre eles, outros apontaram seu êxito econômico e social.
The University For All Program (ProUni) emerged as a public policy which guarantees the entry and permanence of the young people without resources in private universities. The Program was born because of Federal Government initiative and its implementation took place in different colleges and universities of Brazil, since 2005. We study the case of the graduated students who have benefited in the "Centro Universitário Estácio/FIB", in Salvador, Bahia, Brazil. As sampling, it were interviewed the students who were benefited with the ProUni in 2005, the most part graduated as from 2008 and which already in the market job. Some interviewees have pointed the Program as benefic and others have pointed some deficiencies and, among them, others have pointed their economic and social success.
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Andrade, Vanessa Gutierrez de. "Influência dos antivirais de ação direta na resistência insulínica, nos marcadores de fibrose e função hepática na cirrose por Hepatite C". Botucatu, 2018. http://hdl.handle.net/11449/180392.
Testo completoAbstract (sommario):
Orientador: Giovanni Faria SilvaResumo: Introdução: O Vírus da Hepatite C está associado a manifestações extra-hepáticas, dentre elas a resistência à insulina (RI). Estudos baseados em Interferon (IFN) e Ribavirina (RBV) mostraram uma melhora da RI e da regressão de fibrose associada à Resposta Virológica Sustentada (RVS), mesmo em pacientes cirróticos.As evidências são incertas se isso ocorre com os Antivirais de Ação Direta (AADs). Objetivos: Avaliar a influência da RVS em cirróticos infectados pelo vírus da hepatite C (VHC) tratados com os AADs na RI, nos Lipídes Séricos, nos marcadores indiretos de atividade inflamatória, nos marcadores indiretos de fibrose hepática e nos escores de avaliação de função hepática. Metodologia: Estudo prospectivo longitudinal realizado no Ambulatório de Hepatites Virais da disciplina de Gastroenterologia do Hospital das Clínicas da Faculdade de Medicina de Botucatu em dois períodos: no início do tratamento (t-base) e na décima segunda semana após o fim do tratamento (t-RVS). Critérios de Inclusão: infecção pelo VHC (RNA-VHC positivo), idade ≥ 18 anos, conclusão da terapia com AADs, presença de cirrose hepática e amostras coletadas no t-base e t-RVS. Critérios de Exclusão: presença de coinfecção VHB/HIV, Carcinoma Hepatocelular no início do estudo ou no t-RVS, pacientes transplantados (fígado/rim). Para confirmação da cirrose utilizou-se a elastografia hepática ou biópsia (METAVIR), como também a clínica ou exames de imagem. Para avaliação indireta da fibrose hepática, utilizou-se ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Introduction: Hepatitis C virus is associated with extrahepatic manifestations, including insulin resistance (IR). Studies based on Interferon (IFN) and Ribavirin (RBV) have shown an improvement in IR and fibrosis regression associated with Sustained Virological Response (SVR), even in cirrhotic patients. This evidence is uncertain if this occurs with Direct Action Antivirals (DAAs). Objective: To evaluate the influence of SVR on hepatitis C virus (HCV) infected cirrhotic patients treated with DAAs in IR, Serum Lipids, indirect markers of inflammatory activity, indirect markers of hepatic fibrosis and evaluation scores of hepatic function. Methods: Prospective longitudinal study conducted at the Viral Hepatitis Outpatient Clinic of the Gastroenterology Department of the Clinical Hospital of Botucatu Medical School in two periods: at the beginning of treatment (t-base) and at the twelfth week after the end of treatment (t-SVR). Inclusion Criteria: HCV infection (age-positive HCV RNA), age ≥ 18 years, completion of DAAs therapy, presence of liver cirrhosis and samples collected at t-base and t-SVR. Exclusion Criteria: presence of HBV / HIV coinfection, Hepatocellular Carcinoma at baseline or in t-SVR, transplanted patients (liver / kidney). To confirm cirrhosis, hepatic elastography or biopsy (METAVIR) was performed, as were clinical or imaging tests. The following formulas were used for the indirect evaluation of hepatic fibrosis: APRI = AST (UI / L) / AST (UI / L) Normal Limi... (Complete abstract click electronic access below)
Mestre
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Waqar, Ammar Bin. "Exploration of Electrodeposition of Aluminum-Nickel Alloys and Multilayers in Organic Chloroaluminate Ionic Liquids". Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5397.
Testo completoAbstract (sommario):
Aluminum-nickel (Al-Ni) alloys and Al/Ni bilayers were successfully electrodeposited from AlCl3-EMIM-NiCl2 electrolyte at room temperature. Dissolution of NiCl2 was shown to be favorable in Lewis basic (with molar ratio of AlCl3 < 0.5) AlCl3-EMIM solution. The use of electrochemically active Cu working electrode as opposed to inert W induced additional Cu oxidation and dissolution in the cyclic voltammetry scan. The reduction potentials of Al and Ni were found to be ~ – 0.3 and 0.15 V vs. Al/Al3+ respectively. Increasing [NiCl2] in the electrolyte leads to an increase of Ni concentration in the deposited structures. Dense and well-adherent Al-Ni alloys with Ni concentration up to 17.7 at.% were deposited by potential control. XRD analysis revealed that the deposited Al-Ni exhibit a supersaturated fcc crystalline structure. The visual appearance of the deposits ranged from bright silver, dull silver, grey, to black, where the darker shade typically indicated higher Ni content. SEM analysis revealed that the surface morphology of the deposits ranged from nodular to flake-like structures. Al-Ni alloy typically showed nodular morphology with cauliflower structure. Flake structures, which were independent of substrate roughness, were found to develop under pulsed potential deposition with 1:1 duty ratio.
The concentration of Ni in electrodeposited Al-Ni alloys increases nonlinearly with the increase in molarity of NiCl2. Al and Ni contents increase with increasing the time of positive and negative cycle of the pulse respectively. Decreasing the frequency by half resulted in almost double the amount of Ni in the deposited alloy. A smoother substrate increased Ni concentration from 6 to 17.7 at.%. Al/Ni bilayer was successfully deposited in 1.5:1 AlCl3-EMIM containing 0.026 M NiCl2. Deposition of Al on Ni was achieved using constant potential and pulse potential control. The deposition of Ni on Al is complicated since the deposition potential of Ni lies in the vicinity of Al stripping potential thus inducing competition between Ni deposition and Al stripping.
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Bezerra, Nilva Aparecida Pacheco. "Migração em Palmas/TO: a felicidade no imaginário social". Universidade Federal do Tocantins, 2013. http://hdl.handle.net/11612/692.
Testo completoAbstract (sommario):
A presente dissertação propõe-se fazer uma análise da felicidade a partir do espaço migratório que consolidou Palmas, capital do estado do Tocantins, como a última cidade projetada do século XX. A formação populacional de Palmas, bem como sua expansão demográfica ocorreram, sobretudo, a partir da migração. Um fluxo que se mantém constante e atua fortemente na produção espacial de seu território. Ao tratar de uma população, notoriamente migrante, parte-se da hipótese de que a felicidade, enquanto sentimento que hidrata a vida do ser humano, manifesta-se no imaginário social do indivíduo. O método utilizado nesse percurso foi a fenomenologia, sobretudo, a fenomenologia bachelardiana. A partir dela, expandiu-se a base teórica para outras áreas afins à geografia para compreender as relações inerentes ao imaginário migrante em busca da felicidade. Assim, partiu-se da felicidade subjetiva em busca da felicidade intersubjetiva. Tomando o sujeito como protagonista do espaço, o objetivo foi analisar a felicidade no imaginário social dos migrantes. Partiu-se das narrativas orais concedidas em entrevista, dos mosaicos de imagens colhidas durante análise e observação da cidade, para, no confronto com os conteúdos teóricos, apresentar os elementos indicativos de felicidade na construção socioespacial da cidade. Apreendeu-se que, entre presenças e ausências, as imagens elaboradas pelos indivíduos materializam-se na forma de um espaço feliz ou (in)feliz. Constatou-se que a imaginação, enquanto elemento criador de imagens, materializa-se no espaço na forma de bem-estar e felicidade, assumindo uma socioespacialidade.Esta disertación propone hacer un análisis de la felicidad desde el espacio migratório que consolidó Palmas, capital del Estado de Tocantins, como la última ciudad proyectada del siglo XX. La formación de la población de Palmas, así como su expansión demográfica, se produjeron principalmente de la migración. Un flujo que es constante y actúa fuertemente sobre la producción espacial de su territorio. Al abordar una población notablemente migrante, se parte del supuesto de que la felicidad, considerada sentimiento que hidrata la vida del ser humano, se manifiesta en el imaginario social de la persona. El método utilizado en este trabajo fue la fenomenología, especialmente la fenomenología de Bachelard. Desde la fenomenología bachelardiana se amplió la base teórica hacia otras áreas relacionadas con la geografía, a fin de entender las relaciones inherentes al imaginario migrante en búsqueda de la felicidad. Por lo tanto, se partió de la felicidad subjetiva en búsqueda de la felicidad intersubjetiva. Considerando al individuo como protagonista del espacio, el objetivo ha sido analizar la felicidad en el imaginario social de los migrantes. Partimos de narraciones orales concedidas en entrevistas, de mosaicos de imágenes tomadas durante el análisis y la observación de la ciudad, para en la comparación con los contenidos teóricos, presentar los elementos indicativos de la felicidad, en la construcción socioespacial de la ciudad. Se aprehendió que entre presencias y ausencias, las imágenes producidas por los individuos se materializan en forma de un espacio feliz o (in)feliz. Se encontró que la imaginación, considerada elemento creador de imágenes, se materializa en el espacio en forma de bienestar y felicidad asumiendo una socioespacialidad.
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Pratsch, Christoph. "New methods for high resolution 3D imaging with X-rays". Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19238.
Testo completoAbstract (sommario):
In der Arbeit haben wir die Grenzen der weit verbreiteten tomographischen
Rekonstruktion von 3D-Proben mittels Transmissionsröntgenmikroskopie charakterisiert.
Wir zeigen, dass die 3D-Auflösung mit diesem Ansatz durch die Schärfentiefe
begrenzt ist. Zur Untersuchung von Alternativen führten wir Simulationen
zur Bildentstehung in einem konfokalen Röntgenmikroskop und einem FIB-SXM
durch. Wir zeigen, dass FIB-SXM ein vielversprechender Ansatz ist, der eine isotrope
3D-Aulösung um die 10 nm erreichen kann und zusätzlich ein drastisch
verbessertes Signal-Rausch-Verhältnis bieten könnte. Wir stellen auch eine neue
Holographiemethode vor, die sich für Vollfeldabbildungen mit kurzen kohärenten
Röntgenpulsen als vorteilhaft erweisen und neue Einsichten in die ultraschnelle
Physik liefern könnte.We have characterized the limitations of the most powerful and widely used 3D X-ray imaging approach, transmission X-ray microscopy with tomographic reconstruction. We show that 3D resolution in this approach is limited by the depth of field. To investigate alternatives, we perform simulations of a confocal transmission X-ray microscope and a FIB-SXM. We show that FIB-SXM is a very promising approach that could o er 3D isotropic resolution at 10 nm with dramatically improved signal to noise. We also introduce a new holography method that could prove bene cial for full eld imaging with short coherent X-ray pulses and yield new insights into ultrafast physics.
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Amiard, Guillaume. "Utilisation du FIB pour la nanostructuration et l'auto-assemblage de réseaux de nano-objets pour des applications microélectroniques". Phd thesis, Aix-Marseille Université, 2012. http://tel.archives-ouvertes.fr/tel-00796428.
Testo completoAbstract (sommario):
Les travaux présentés dans ce manuscrit, sont basés sur l'étude de l'auto-organisation de la matière à l'échelle nanométrique. A cette échelle, les énergies de surfaces jouent un rôle prépondérant dans cette organisation. Pour comprendre au mieux ses mécanismes nous avons étudié plusieurs types de structures à base de Silicium et de Germanium. Nous avons expérimentalement étudié la croissance cristalline ou amorphe sur différents types de substrats (amorphe : SiO2 et cristallins Si ou SOI). Certain de ces substrats furent nano-structurés en utilisant un faisceau d'ions focalisés de type Gallium ou Or-Silicium. De plus nous avons pu utiliser des surfaces différentes telle que le TiO2 ou le Silicium poreux, afin d'étudier l'organisation de la matière sur des pores de petites tailles (inférieurs à 50nm).
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Holzinger, Angelika [Verfasser]. "Investigation of localized electrochemical interfaces with advanced microscopic techniques : AFM-SECM and FIB/SEM tomography / Angelika Holzinger". Ulm : Universität Ulm, 2019. http://d-nb.info/1200022009/34.
Testo completo
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Blankemeier, Andrew R. "Characterization of Pseudomonas fluorescens Biofilm". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1307731184.
Testo completo
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McConkie, Thomas O. "Curious Growth of a Buried SiO2 Layer". BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3755.
Testo completoAbstract (sommario):
Initial investigation of Moxtek wire grid polarizers composed of Al and coated with SiO2 - SiX - SiO2 (where SiX is used to indicate a Si rich layer whose complete composition is not to be disclosed for proprietary reasons) showed a growth of 3x in the inner (closest to Al) SiO2 layer after baking. Upon removing the X and varying rib composition and layering composition and geometries in 12 sets of before and after samples, no obvious growth was observed. Even baking the original unbaked sample yielded no growth. Our data suggest that the initial conclusion of buried oxide growth was flawed and that the observed changes in optical properties upon baking are either very sensitive to layer thicknesses (smaller than we can confidently observe) or due to some other mechanism. Here we present our sample preparation and analysis using the Focused Ion Beam (FIB), Scanning Transmission Electron Microscopy (STEM), and Energy Dispersive Xray Spectroscopy (EDXS).
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SILVA, LUCIANA FERREIRA. "3D IMAGE ACQUISITION, PROCESSING AND ANALYSIS: MICROCT AND FIB-SEM IN THE CHARACTERIZATION OF DEFECTS IN WET WELDS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=25051@1.
Testo completoAbstract (sommario):
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
A caracterização tridimensional tem sido mais utilizada na área da ciência dos materiais devido à necessidade de melhor compreensão e resultados mais precisos acerca da microestrutura dos materiais, que não são completamente revelados pelas técnicas tradicionais de microscopia bidimensional. No presente trabalho dois tipos de técnicas de caracterização 3D foram utilizadas: MicroTC - Microtomografia de Raios-X (com tomógrafos de bancada e baseados em fonte síncrotron) e FIB-SEM (feixe de íons focalizados acoplados a um MEV). Estas técnicas foram aplicadas a um sistema específico: descontinuidades em metal de solda subaquática molhada. Estas descontinuidades (poros, trincas e inclusões) apresentam tamanhos típicos variando de nanômetros a dezenas de micrômetros. Além disso, apresentam formas, distribuição espacial e orientação bastante variada e complexa. Assim, esta tese apresenta o desenvolvimento de metodologia de aquisição, processamento, análise e visualização 3D de poros, trincas e inclusões em solda subaquática molhada, a partir de imagens obtidas por MicroTC e FIB-SEM. As técnicas de aquisição foram otimizadas para os diferentes tipos de descontinuidades. Rotinas especializadas de processamento e análise de imagens foram criadas, sempre que possível utilizando um ambiente de software livre (FIJI/ImageJ). Diversas medidas foram automaticamente obtidas: número de objetos, volume, fração volumétrica, área superficial, diâmetro de Feret, espessura, esfericidade e compacidade. Além disso, a construção de imagens 3D permitiu observar a forma e a distribuição espacial das descontinuidades presentes. Visando avaliar a sensibilidade para detecção de trincas por MicroTC, um corpo de prova com seção variável foi submetido a um ensaio de tração, de forma que as diferentes seções sofressem diferentes valores de tensão. Foi verificada uma correlação positiva entre o valor de tensão e o número, comprimento e espessura das trincas detectadas. Este experimento também revelou o impacto da resolução espacial e do ruído sobre a possibilidade de detectar as trincas de forma acurada.
3D characterization is growing quickly in materials science due to the demands of better microstructural characterization, which cannot be fully achieved with the traditional 2D microscopy techniques. In this work, two types of 3D characterization techniques were employed: MicroCT – microcomputed x-ray tomography (with both bench top and synchrotron sources) and FIB-SEM (focused ion beam coupled to SEM). These techniques were applied to a specific system: discontinuities in underwater wet welds. These discontinuities (pores, cracks and inclusions) range in size from nanometers to tens of microns. Moreover, they present complex and varied shapes, spatial distribution and orientation. Thus, this thesis presents the development of methodology for the acquisition, processing, analysis and visualization of pores, cracks and inclusions in underwater wet welds, from images obtained by MicroCT and FIB-SEM. The acquisition techniques and conditions were optimized for the different kinds of discontinuities. Specialized routines for image processing and analysis were developed, employing a free software environment whenever possible (FIJI/ImageJ). Several measurements were automatically obtained: number of objects, volume, volume fraction, surface area, feret diameter, thickness, sphericity and compacity. Moreover, the rendering of 3D images allowed the observation of the shape and spatial distribution of the discontinuities in the weld metal. To evaluate the detection sensitivity of cracks by MicroCT, a specimen with varied cross-sections was submitted to a tensile test, so that the different sections were submitted to to different stress values. A positive correlation was observed between the stress value and the number, length and thickness of the detected cracks. This experiment also showed the influence of spatial resolution and noise upon the possibility of detecting cracks accurately.
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Cá, Lamo-Guzmá N. Bernardo, Vinatea-Serrano Luis De, Alejandro Piscoya e Eddy R. Segura. "Performance of the FIB-4 index in esophageal varices screening in patients with the diagnosis of liver cirrhosis". Sociedad de Gastroenterología del Perú, 2020. http://hdl.handle.net/10757/655701.
Testo completoAbstract (sommario):
INTRODUCTION: The diagnosis of esophageal varices in cirrhotic patients is made by the upper gastrointestinal endoscopy. Multiple non-invasive predictors have been studied for the diag-nosis of esophageal varices. The objective of this study is to testthe FIB4 index as screening of esophageal varices in patients with liver cirrhosis. MATERIALS AND METHODS: A cross-sectional analytic study was developed in four national hospital using hepatic cirrhosis patient's medi-cal files. We assessed the information using univariate and bivariate analysis, sensitivity, speci-ficity, predictive positive and negative value, the positive and negative likelihood ratio calcu-lation of the esophageal varices screening and its size. We built ROC curve for every analysis group. RESULTS: The study included 289 liver cirrhosis patients. Most of the patients were male (54.33%). 77.85% patients had esophageal varices. The distribution of varices was 19.03%, 35.99% and 22.84% for large, medium and small varices, respectively. In the FIB-4 index analysis for the presence of varices, it was found a sensitivity of 81.3%, specificity of 37.5% (AUC: 0.57). The calculation for variceal size showed a sensitivity of 81.8%, specificity of 23.9% (AUC: 0.50). In the analysis of FIB-4 index for prophylaxis groups was found a sensitivity of 81.8% and a specificity of 28.5% (AUC: 0.54). CONCLUSIONS: The FIB-4 index has no good performance in the screening for the presence of esophageal varices and its size in liver cirrhosis patients.Revisión por pares
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Laipple, Daniel [Verfasser], e Andreas [Akademischer Betreuer] Schreyer. "Region of interest synchrotron nanotomography and nanodiffraction with FIB/SEM characterisation on engineering materials / Daniel Laipple. Betreuer: Andreas Schreyer". Hamburg : Staats- und Universitätsbibliothek Hamburg, 2015. http://d-nb.info/1073970396/34.
Testo completo
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Laipple, Daniel Verfasser], e Andreas [Akademischer Betreuer] [Schreyer. "Region of interest synchrotron nanotomography and nanodiffraction with FIB/SEM characterisation on engineering materials / Daniel Laipple. Betreuer: Andreas Schreyer". Hamburg : Staats- und Universitätsbibliothek Hamburg, 2015. http://nbn-resolving.de/urn:nbn:de:gbv:18-74020.
Testo completo
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Rooney, Aidan. "Characterisation of buried interfaces in van der Waals materials by cross sectional scanning transmission electron microscopy". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/characterisation-of-buried-interfaces-in-van-der-waals-materials-by-cross-sectional-scanning-transmission-electron-microscopy(dd5565b9-1709-4d28-b4ce-9cd675fb36eb).html.
Testo completoAbstract (sommario):
Graphene and other two-dimensional materials can be stacked together to form vander Waals heterostructures: synthetic crystals composed of different atomically thin layers with a bespoke electronic band structure. Structural characterisation of vander Waals heterostructures is difficult using conventional methods as the properties are almost entirely defined by the nature of the buried interfaces between dissimilar crystals. These methods also fall short of resolving the atomic structure of buried defects in van der Waals materials such as graphite. This work demonstrates the refinement and successful application of ion beam specimen preparation to produce cross sectional slices through these unique crystals so that they can be characterised by high resolution scanning transmission electron microscopy (STEM). Cross sectional specimen were prepared using in situ lift-out in a focused ion beam (FIB) dual-beam instrument. The fine polishing steps were optimised to prevent damage to the core of the specimen. High resolution STEM imaging of twin defects in graphene, hexagonal boron ni-tride and MoSe2 revealed that the boundaries are not atomically sharp but extended across many atoms. Advanced processing and analysis of these images uncovered fundamental mechanics which govern their geometry. This technique was further applied to complex transition metal dichalcogenide heterostructures to quantitatively determine the properties of buried interfaces between atomically thin crystals.
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Stephenson, David E. "Microstructure and Transport Properties of Porous Li-ion Electrodes". BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2752.
Testo completoAbstract (sommario):
The goal of this work is to understand the relationships between electrode microstructure and mass transport resistances. One can use this information to predict cell performance from fundamental principles. This work includes new types of particle-scale 3D models for correlating and predicting the effects of electrode microstructure on both ionic and electronic transport. The 3D models imitate the sub-micrometer-scale arrangement of active material particles, carbon, binder, and pores and use FIB/SEM images as a basis for parameterization. The 3D models are based respectively on the statistical mechanics techniques of molecular dynamics and Monte Carlo. The approach closely related to molecular dynamics, named the dynamic particle packing (DPP) model, uses aggregates of spheres to recreate electrode microstructures. The other approach, named the stochastic grid (SG) model, is closely related to Monte Carlo techniques in which a small set of fundamental interdomain and bulk energy parameters are used to generate structures.In order to predict electrode microstructures we correlated the fundamental interdomain and bulk energy parameters for the SG model to electrode mass composition and porosity. We used the revised computer program, known as predict SG, to estimate structures of which there are no experimental measurements of electrode structure. From these predicted electrode structures we obtained electronic and ionic transport properties. This allowed us to estimate the trade-offs between ionic and electronic transport for different porosities and carbon fractions. We found from experimental measurements of electrode structure that carbon and binder formed distinct agglomerates. From the 3D models we determined at commercial fractions of carbon and binder that the conductivity of these carbon agglomerates plays a large role in determining both the electronic and ionic pathways. So in order to better understand the role that these carbon/binder agglomerates play, we explored and developed several experimental methods to find the electronic and ionic conductivity of both simulated carbon domains and complete electrode films. The goal was not only to elucidate the role carbon agglomerates play, but also to develop a non-destructive method of determining overall film properties. Although we found that a non-destructive method is extremely challenging due to probe contact resistances, we did find success in determining carbon domain properties using a delamination method.
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Fraczkiewicz, Alexandra. "Développement de la tomographie par rayons X en synchrotron pour l'industrie : application à l'analyse de défaillance en intégration 3D". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY088/document.
Testo completoAbstract (sommario):
Ce travail de thèse vise à développer de nouvelles techniques de caractérisation pour l'intégration 3D en micro-électronique. Plus précisément, ce travail porte sur l'imagerie 3D de tels objets et la mesure des contraintes par diffraction de Bragg, réalisées sur de récentes lignes de lumière de l'ESRF (European Synchrotron Radiation Facility).L'intégration 3D a pour but de répondre aux besoins de performances de la micro-électronique, en empilant les différents éléments constituant les puces au lieu de les placer les uns à côté des autres; ceci permet de limiter la place qu'ils occupent et la longueur des connections. Pour ce faire, de nouvelles connections entre puces ont du être développées, telles que les piliers de cuivre et les pads de cuivre, utilisés dans le cas du collage hybride. Afin de maîtriser leurs procédé de fabrication, il est important de pouvoir caractériser ces objets, à la fois par des moyens d'imagerie et de mesure de la déformation dans les puces. Ces mesures doivent permettre un large champ de vue (100 µm), ainsi qu'une haute résolution (50 nm). De plus, afin de satisfaire les besoins en temps de l'industrie micro-électronique, les techniques choisies doivent être aussi rapides et automatiques que possible.Pour satisfaire ces besoins, plusieurs techniques ont été étudiés durant ces travaux de thèse.Une technique d'imagerie 3D par Slice and View, inspirée de la technique classique du FIB/SEM et implémentée dans un PFIB (Plasma Focused Ion Beam), a été développée durant ces travaux de thèse. Elle permet aujourd'hui l'acquisition de larges volumes de manière automatique. De même, le procédé d'analyse des mesures de tomographies réalisées sur la ligne de lumière ID16A de l'ESRF a été adapté, afin de limiter au maximum l'intervention humain et le temps global d'analyse.Des mesures de déformations ont également été menées à l'ESRF, sur une ligne de nano-diffraction, ID01. Ces expériences ont été réalisées sur des empilements dédiés au collage, hybride ou direct. Il a été possible de mesurer en une seule expérience les déformations présentes dans deux couches de silicium, et de réaliser des mesures textit{in situ} dans le cuivre.Dans les travaux de thèse présentés ici, nous montrons les possibilités de techniques synchrotron (imagerie et mesure de déformations) pour la caractérisation d'objets issus de l'intégration 3D. Nous montrons que certaines adaptations des techniques existante peuvent permettre des analyses routinières à haute résolution pour le milieu de la micro-électroniqueThis PhD thesis aims at developing new characterization techniques for 3D integration in microelectronics. More specifically, the focus is set on recent ESRF (European Synchrotron Radiation Facility) beamlines, both for 3D imaging by tomography and for strain measurements by Bragg diffraction.3D integration aims at reducing the global microelectronics devices footprint and connections length, by stacking the dies on top of one another instead of setting them one to another. This new geometry however requires new connections, such as copper pillars (CuP) and copper pads, used in hybrid bonding. The monitoring of their fabrication process requires their imaging in three dimensions, and the measure of the strain inside them. Those measurements must be conducted on large areas (100 µm2), with high resolution (500 nm for strain and 100 nm for imaging). Moreover, given the industrial context of this study, the characterization methods must be as routine and automatic as possible.To answer those needs, several techniques have been developed in this work.Two 3D imaging techniques have been made compatible with the requirements of 3D integration characterization. A Slice and View procedure has been implemented inside a single beam PFIB, leading to large volumes 3D automated imaging. The tomography workflow accessible on the ID6A beamline of the ESRF has been adapted, in order to limit the human intervention and beam times. This leads to possible statistical measurements on this beamline.Strain measurements have been conducted on the ID01 beamline of the ESRF, on silicon and copper stacks meant for direct and hybrid bonding. They allowed for simultenous local strain measurements in two independent layers of silicon, and textit{in situ} measurements in copper.In this work, we show the possibilities of synchrotron based techniques (here, tomography and Bragg diffraction) for the chacracterization of 3D integration devices. We show that, provided some adjustments, these techniques can be used routinely for the microelectronics field
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Лішневська, Анастасія Геннадіївна, Анастасия Геннадьевна Лишневская, Anastasiia Hennadiivna Lishnevska, Микола Дмитрович Чемич, Николай Дмитриевич Чемич, Mykola Dmytrovych Chemych, Олег Борисович Берест, Олег Борисович Берест, Oleh Borysovych Berest e V. Parashchenko. "Features of clinical and biochemical changes and indicators of APRI and FIB-4 in patients with chronic viral hepatitis C". Thesis, Lithuanian University of Health Sciences, 2020. https://essuir.sumdu.edu.ua/handle/123456789/81099.
Testo completoAbstract (sommario):
Хронічний вірусний гепатит С (ХВГС) - поширене і небезпечне захворювання печінки.
Вірусне ураження печінки прогресує від запалення до розвитку фіброзу і цирозу.
Ступінь фіброзу печінки важливий для визначення терапевтичної тактики і подальшого спостереження.Хронический вирусный гепатит С (ХВГС) - распространенное и опасное заболевание печени. Вирусное поражение печени прогрессирует от воспаления до развития фиброза и цирроза. В Степень фиброза печени важна для определения терапевтической тактики и дальнейшего наблюдения.
Chronic viral hepatitis C (CVHC) is a common and dangerous liver disease. Viral liver damage progresses from inflammation to the development of fibrosis and cirrhosis. The degree of liver fibrosis is important for determining therapeutic tactics and further observation.
49
Rossini, Giuseppe. "Analyse et design des stratégies d'acheminement pour les réseaux centrés sur l'hôte et sur le contenu". Electronic Thesis or Diss., Paris, ENST, 2014. http://www.theses.fr/2014ENST0005.
Testo completoAbstract (sommario):
A partir des limites réelles de l'Internet, dans cette thèse, nous étudions différents aspects de deux directions dont l'Internet évolue. En particulier, nous considérons des moyens plus souples pour joindre les hôtes du réseau, et pour distribuer du contenu. Host Centric Networking (HCN) est le nom que nous donnons à l'ensemble des architectures qui tentent de découpler la position et l'identification d'un hôte. Fondamentalement, ils identifient chaque nœud par des étiquettes plates qui ne localisent pas l'hôte dans le réseau. Les architectures HCN utilisent Distributed Hash Tables ( DHT ) pour récupérer la position de l'hôte de l'étiquette correspondante.Toutefois, l'acheminement et la transmission sous-jacente à la DHT, s'appuient fortement sur des algorithmes traditionnels basés sur des chemins uniques. Ainsi, dans la première partie, nous proposons APLASIA, une architecture de routage alternatif composé principalement par un algorithme de recherche de chemin, à savoir APL, et par un plan de données de autoforwarding. Information Centric Networking (ICN) rend le contenu directement adressable par les hôtes du réseau. L'idée de base consiste à envoyer des paquets portant l'identifiant de contenu, plutôt que l'adresse de l'hôte. Comme le contenu peut être facilement mis en cache dans les périphériques réseau, un réseau ICN peut être modélisée comme un réseau de caches orienté vers le récepteur. Dans la deuxième partie de ce travail, nous considérons la mise en oeuvre des algorithmes déployés sur un réseau de cachesStarting from the evidence of the Internet’s actual limits, in this Thesis we investigate different aspects of two directions the Internet is evolving toward. In particular, we consider more flexible ways to reach hosts, and to distribute content. Host Centric Networking (HCN) is the name we give to the umbrella architectures which try to decouple host location and identifiers. Basically, they identify each device by the means of flat labels which do not locate the host within the network. HCN architectures leverage Distributed Hash Table(DHT) approaches for retrieving the host position from the corresponding label. However, routing and forwarding underlying the DHT, heavily rely on traditional single path algorithms. Thus, in the first part we propose APLASIA, an alternative routing architecture mainly composed by a path-finding algorithm, namely APL, and by an autoforwarding data plane. Information Centric Networking (ICN) makes content directly addressable by network hosts. The basic idea is to send packets carrying the content identifier, rather than the host address. As content can be easily cached within network devices, an ICN network can be modeled as a receiver driven network of caches. Indeed, in the second part of this work, we consider caching algorithms deployed over a network of caches. Each of these algorithms is a triplet composed by forwarding (which path is worth following), meta-caching (what content is worth caching), and replacement (what content is worth replacing) strategies
50
Spurio, Eleonora. "Electrical conductivity of single Be-doped GaAs nanowires". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19295/.
Testo completoAbstract (sommario):
In this thesis the measurement of the current-voltage characteristics of single nanowires in their as-grown geometry is presented. The studied sample is composed by Be-doped GaAs nanowires grown on Si substrate by molecular beam epitaxy. The measurements have been performed using the two terminal and the four terminal geometry, respectively in the laboratories of Universität Siegen and of Leibniz Universität Hannover. For applications of nanowires in optoelectonic applications the knowledge of electronic properties is fundamental for device optimization. The first aim of this work is the investigation of electric properties of individual nanowires onto the same substrate. The electrical characterization has been performed measuring the current-voltage characteristics of single nanowires in the 2-terminal and 4-terminal geometry. The resistance of single nanowires onto the same substrate has been calculated by fitting the obtained characteristics using thermionic emission theory. The obtained values are different from nanowire to nanowire, meaning differences in conductivity of nanowires on the same substrate. Then, the resistance profile along single nanowires has been measured in the 2-terminal geometry. This measurement shows a quasi-exponential decrease in nanowire conductivity from the bottom to the top part of individual nanowires. The experimental results are in good agreement with numerical simulations obtained using Finite Element Method calculations. The correct implantation of nanowires onto real devices also requires the knowledge of the correlation between the mechanical stress applied to single nanowires and their electric properties. The analysis of this correlation has been performed using the 2 terminal configuration, by applying different mechanical stress to the same nanowire and measuring the current-voltage characteristic at each step. The results show an increase in conductivity of the single nanowire with the increase of the applied tension.