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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Contribution à l'étude du transport ambipolaire dans les transistors organiques : impact du procédé de fabrication sur les performances des couches minces / Contribution to the study of ambipolar transport in organic transistors : fabrication process' impact on thin films performances

Nénon, Sébastien 08 October 2010 (has links)
L'électronique plastique est devenue en une dizaine d'années un domaine actif, tant en recherche fondamentale qu'en application. La compréhension et le contrôle des forces motrices du transport ambipolaire est un objectif clé de la recherche dans le domaine de l'électronique organique, et plus particulièrement des transistors. Après une introduction rappelant les principes des transistors organiques ambipolaires et un état de l'art du domaine, les outils et méthodes utilisés au cours de ce travail ont été présentés. Le premier chapitre présente les résultats obtenus des transistors réalisés par évaporation sous vide de phtalocyanines de cuivre. Dans un premier temps la stabilité et les performances des deux semi-conducteurs isolés ont été caractérisés, puis une étude morphologique, électrique et structurelle a été menée sur des dispositifs en structure bicouche ou interpénétrée. Le deuxième chapitre présente une nouvelle méthode d'élaboration de transistors : le LIFT (LAser Induced Forward Transfer). Les premiers transistors à canal p et n'ont ainsi été réalisés à base de phtalocyanines de cuivre, avant de tenter d'obtenir des dispositifs ambipolaires. Cette méthode récente peut permettre de déposer des films à une très grande cadence menant à des dispositifs microstructurés de grande précision. Le dernier chapitre présente une approche par voie liquide. Des solutions de DH-DS2T et PDIF-CN2 ont été élaborées afin de réaliser des encres par le mélange de ces deux solutions pour être déposées par tournette ou dépôt par goutte. en conclusion, les différentes méthodes sont évaluées et comparées afin de déterminer leur utilité et applicabilité respectives. / During the past decade, plactic electronics has become an active research domain, both fundamental and application side. Undestanding and controling the phenomenom which rule the ambipolar transport is one of the main aims of research in organic electronics and transistors. After an introduction giving the principles and a state of the art of organic ambipolar transistors, materials and methods used are described. The first chapter deals with the results obtains whith transistors based on copper phtalocyanines elaborated by a vacuum evaporation process. Stability is isolated moieties was first investigated. Then, morphology, performance and structure of bilayer and blend systems. The second chapter presents the results obtained for transistors elabored by LIFT (Laser Induced Forward Transfer). The first n-channel and p-channel transistors elabored by laser deposition were obtained from copper phtalocynanines. Then the possibility to obtain ambipolar decives was investigated. This brand new technology can permit to create microstructures with a great deposition velocity. The last chapter presents the liquid way approach. DH-DS2T and PDIF-CN2 solutions were used to realise link by mixing the two solutions. those ink where deposited by drop-cast or spin-coating. Finally, the different methods used in this work were evaluated and compared in order to define their usefulness and applicability
92

Development of 3D filter made by stereolithography / Développement de filtre 3D fabriqué par stéréolithographie

Marchives, Yoann 12 October 2016 (has links)
Les télécommunications sont devenus indispensables dans notre monde actuel. De plus, le volume des données échangées ne cesse de croître. En effet, nous pouvons transmettre nos photos, nos vidéos au monde entier. Nonobstant, nous ne voulons pas attendre pour les avoir, ce qui exige un débit de données très important et par conséquent des signaux avec des bandes passantes plus larges. Les satellites de télécommunications doivent donc s’adapter, c'est pourquoi nous proposons dans ces travaux la recherche de filtre à large bande avec une recherche de compacité et de faibles pertes. Nous nous sommes intéressés à l'utilisation de matériaux céramiques qui permettent d'obtenir de bonnes performances vis à vis de nos besoins. Notre travail est aussi rendu possible par le développement de procédés de fabrication additifs, comme par exemple la stéréolithographie, qui va nous permettre de nous affranchir fortement de règles de dessin contraignantes que nous pourrions avoir en utilisant des procédés classiques. Nous avons développé des filtres avec de larges bandes passantes autour de 4GHz. Une première étude nous a permis de rechercher des concepts qui permettent d'obtenir de forts couplages, conditions sine qua non pour réaliser ces filtres. Plusieurs concepts sont présentés ainsi que leur fabrication et leur mesures. Nous avons ainsi démontré expérimentalement que les concepts proposés, à base de pièces monoblocs céramiques, sont capables de produire des filtres à bandes passantes supérieures à 60 % (voire même 110 % pour une version améliorée). / Every day, the data exchanges increase thanks to the new technologies. We can keep our files, our pictures, our videos online to have an access anywhere on the planet (for now). In this way, the data output of the telecommunication systems has to be increased in order to satisfy the more and more demanding users. One way to allow this is to increase the bandwidths of the different signals, making possible to transmit more data at the same time. In this work, we will develop wide bandpass filters dedicated to space telecommunications. For that purpose, we need them to be compact, with low insertion loss and a limited number of parts to assemble. Consequently, we are interested to use resonators made with ceramic materials that permits to reach such properties. Moreover, these materials are compatible with stereolithography, an additive manufacturing process. Such technology is here very useful for our purpose since its design freedom allows the creation of almost all kind of geometries. To realize such wide bandpass filters, we need strong couplings between the different resonators and also for the accesses, so we will present our studies focused on reaching these specific objectives. Then, we will present different designs of wide bandpass filter around 4GHz. After different generation of ceramic based components, we are be able to experimentally create a 60% bandwidth (even 100% for our last version) very compact bandpass filter filling the objectives of this PhD thesis.
93

Development of New Structural Health Monitoring Techniques

Fekrmandi, Hadi 16 March 2015 (has links)
During the past two decades, many researchers have developed methods for the detection of structural defects at the early stages to operate the aerospace vehicles safely and to reduce the operating costs. The Surface Response to Excitation (SuRE) method is one of these approaches developed at FIU to reduce the cost and size of the equipment. The SuRE method excites the surface at a series of frequencies and monitors the propagation characteristics of the generated waves. The amplitude of the waves reaching to any point on the surface varies with frequency; however, it remains consistent as long as the integrity and strain distribution on the part is consistent. These spectral characteristics change when cracks develop or the strain distribution changes. The SHM methods may be used for many applications, from the detection of loose screws to the monitoring of manufacturing operations. A scanning laser vibrometer was used in this study to investigate the characteristics of the spectral changes at different points on the parts. The study started with detecting a load on a plate and estimating its location. The modifications on the part with manufacturing operations were detected and the Part-Based Manufacturing Process Performance Monitoring (PbPPM) method was developed. Hardware was prepared to demonstrate the feasibility of the proposed methods in real time. Using low-cost piezoelectric elements and the non-contact scanning laser vibrometer successfully, the data was collected for the SuRE and PbPPM methods. Locational force, loose bolts and material loss could be easily detected by comparing the spectral characteristics of the arriving waves. On-line methods used fast computational methods for estimating the spectrum and detecting the changing operational conditions from sum of the squares of the variations. Neural networks classified the spectrums when the desktop – DSP combination was used. The results demonstrated the feasibility of the SuRE and PbPPM methods.
94

Development of New Structural Health Monitoring Techniques

Fekrmandi, Hadi 16 March 2015 (has links)
During the past two decades, many researchers have developed methods for the detection of structural defects at the early stages to operate the aerospace vehicles safely and to reduce the operating costs. The Surface Response to Excitation (SuRE) method is one of these approaches developed at FIU to reduce the cost and size of the equipment. The SuRE method excites the surface at a series of frequencies and monitors the propagation characteristics of the generated waves. The amplitude of the waves reaching to any point on the surface varies with frequency; however, it remains consistent as long as the integrity and strain distribution on the part is consistent. These spectral characteristics change when cracks develop or the strain distribution changes. The SHM methods may be used for many applications, from the detection of loose screws to the monitoring of manufacturing operations. A scanning laser vibrometer was used in this study to investigate the characteristics of the spectral changes at different points on the parts. The study started with detecting a load on a plate and estimating its location. The modifications on the part with manufacturing operations were detected and the Part-Based Manufacturing Process Performance Monitoring (PbPPM) method was developed. Hardware was prepared to demonstrate the feasibility of the proposed methods in real time. Using low-cost piezoelectric elements and the non-contact scanning laser vibrometer successfully, the data was collected for the SuRE and PbPPM methods. Locational force, loose bolts and material loss could be easily detected by comparing the spectral characteristics of the arriving waves. On-line methods used fast computational methods for estimating the spectrum and detecting the changing operational conditions from sum of the squares of the variations. Neural networks classified the spectrums when the desktop – DSP combination was used. The results demonstrated the feasibility of the SuRE and PbPPM methods.
95

Contribution à l'amélioration de l'observabilité et de la reproductibilité des défauts dans les dispositifs semi-conducteurs / Contribution to the improvement of defects observability and reproducibility in semiconductor devices

Welter, Loïc 18 December 2014 (has links)
Les défauts récurrents apparaissant dans des contextes particuliers ont un impact non négligeable sur le rendement, lors de la fabrication des noeuds technologiques nanométriques. C'est pourquoi une nouvelle méthode de contrôle du procédé de fabrication in-situ est développée, en vue d'améliorer la performance globale de l'outil de production. Elle se veut complémentaire des techniques d'analyses de défaillance classique, notamment en cas de crise. Le principe est de transformer un circuit de production en un véhicule de test en réutilisant des éléments qui le composent. Le circuit perd alors sa fonctionnalité originale au profit de fonctions de contrôle du procédé de fabrication réalisées uniquement à base de cellules logiques disponibles en grand nombre dans les circuits. Cette transformation, baptisée «échange topologique», implique la modification de certains niveaux de métallisation et nécessite la création d'un flot de conception particulier, basé sur des techniques d'Engineering Change Order (ECO). Comme plusieurs fonctions doivent pouvoir cohabiter ensemble sur un même véhicule, un système de multiplexage a été évalué. La faisabilité est montrée au travers d'un circuit de test réalisé de manière analogue à un circuit en production. Il est transformé pour l'exemple en un système intégré de contrôle d'épaisseur de diélectrique. / Recurrent defects appearing in specific contexts have a significant impact on nanoscale technology nodes manufacturing process yield. Therefore, a new in-situ process monitoring method is developed to improve the overall performance of the production tool. It is complementary to classical failure analysis techniques, especially when a yield crisis occurs. The idea is to transform a production circuit into a test vehicle by reusing its components. The circuit loses its original functionality in favor of process monitoring functions, carried out only with standard cells widely available in circuits. This transformation, called "topological exchange" involves modifying some levels of metallization and requires the creation of a particular design flow, based on Engineering Change Order (ECO) techniques. As several functions must be able to cohabit on the same vehicle, a multiplexing system is evaluated. Feasibility is shown through a test circuit designed analogously to a production circuit. It is transformed for the example into an integrated dielectric thickness control system.
96

Návrh svařovací robotické buňky / Design of a Robotic Cell for Weding Application

Rolinc, Lukáš January 2019 (has links)
The diploma thesis deals with the design of a workplace with robots designed for spot welding of wire reinforcement of the car seat. After analyzing and description of the given task, the workplace concept is chosen based on the input parameters. Subsequently, sub-systems of the production cell are designed and selected for this concept. For example the design of clamping fixtures, rotary table, input and output storage magazines or the selection of welding guns and robots are solved. The workplace is designed to ensure operator safety and protection. The production cycle of the designed workplace is simulated in Siemens Process Simulate to verify functionality and required productivity of the production line. Technical and economic evaluation of the proposed solution is also included in this diploma thesis.
97

Robotické obrábění s využitím externího nástroje / Robotic machining with external tool

Ryvol, David January 2019 (has links)
The goal of this final thesis is to evaluate the performance of chosen CAM software in robotic deburring of cast parts while using external tool. For this purpose, an analysis of program’s functions was carried out and toolpath-making strategies were compared. The most appropriate strategy for mentioned technology was chosen based on this analysis. The generation of a toolpath was described on the example of real part from automotive industry. In order to simulate real machining process, a model of workspace was created, proper tool with spindle was selected and a method of clamping the workpiece was designed. A postprocessor was created, and so was the robot program, after successful simulation, as a foundation for possible practical test. PowerMill software proved to be not very suitable for this kind of machining application, mainly because of high amount of time consumed during the whole process. So the original idea of replacing classical on-line programming with this software is not advised.
98

Analýza kompletnosti výrobního procesu rozváděčů / Analysis of production process completeness of switchgears

Stokláska, Jiří January 2009 (has links)
This thesis introduces company ABB Brno and its products. It describes the manufacturing process of a switchgear and it is focused at working procedures at particular points of the assembly line. The main part analyzes the root causes of the incompleteness of switchgears in the relation to the components availability. Time footprint was worked out. As a conclusion the proposal of changes in manufacturing process to improve the level of completeness are stated.
99

Optimalizace výrobního procesu ve společnosti / Optimizing the Manufacturing Process in a Company

Vrána, Jakub January 2013 (has links)
This thesis deals with the management of the production process, focusing on unproductive activities. It comprises analysis of the current situation in the company Teva Czech Industries s.r.o. (the TCI) and suggestions for improvement measures. The first chapter presents theoretical basis for processing work. PMT methods, namely MTM and MOST, lean production with a focus on 5S, TPM and Kaizen are described. The second chapter is focused on the company TCI, core business, organization structure and analyzes the current status. It’s focused primarily on the process of critical non-manufacturing operations and the changeover cleaning process. The third chapter, following the analytical part consists of the proposed recommendations. The fourth chapter deals with the final evaluation.
100

Návrh řízení výrobního procesu / Design of a Manufacturing Process Management

Hala, Filip January 2013 (has links)
The aim of this diploma thesis is to create and apply a methodology to improve the manufacturing process. Processes for the passage of a contract through the company and activities of the foreman were analyzed. According to this analysis, a methodology was created for continuous improvement of the manufacturing process. This methodology was applied to the data obtained in the analysis. Based on the application of the methodology, actions have been proposed to improve the production process.

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