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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.
1

Estimation des données manquantes par la métrologie virtuelle pour l'amélioration du régulateur Run-To-Run dans le domaine des semi-conducteurs / Estimation of missing data by virtual metrology for the improvement of the Run-To-Run controller in the field of semiconductors

Jebri, Mohamed Ali 26 January 2018 (has links)
La thématique abordée porte sur la métrologie virtuelle (VM) pour estimer les données manquantes durant les processus de fabrications des semi-conducteurs. L'utilisation de la métrologie virtuelle permet également de fournir les mesures logicielles (estimations) des sorties pour alimenter les régulateurs run-to-run (R2R) mis en place pour le contrôle de la qualité des produits fabriqués. Pour remédier aux problèmes liés au retard de mesures causé par l'échantillonnage statique imposé par la stratégie et les équipements mis en place, notre contribution dans cette thèse est d'introduire la notion de l'échantillonnage dynamique intelligent. Cette stratégie est basée sur un algorithme qui prend en compte la condition de voisinage permettant d'éviter la mesure réelle même si l'échantillonnage statique l'exige. Cela permet de réduire le nombre de mesures réelles, le temps du cycle et le coût de production. Cette approche est assurée par un module de métrologie virtuelle (VM) que nous avons développé et qui peut être intégré dans une boucle de régulation R2R. Les résultats obtenus ont été validés sur des exemples académiques et sur des données réelles fournies par notre partenaire STMicroelectronics de Rousset concernant un processus chemical mechanical planarization (CMP). Ces données réelles ont permis également de valider les résultats obtenus de la métrologie virtuelle pour les fournir ensuite aux régulateurs R2R (ayant besoin de l'estimation de ces données). / The addressed work is about the virtual metrology (VM) for estimating missing data during semiconductor manufacturing processes. The use of virtual metrology tool also makes it possible to provide the software measurements (estimations) of the outputs to feed the run-to-run (R2R) controllers set up for the quality control of the manufactured products.To address these issues related to the delay of measurements caused by the static sampling imposed by the strategy and the equipments put in place, our contribution in this thesis is to introduce the notion of the dynamic dynamic sampling. This strategy is based on an algorithm that considers the neighborhood condition to avoid the actual measurement even if the static sampling requires it. This reduces the number of actual measurements, the cycle time and the cost of production. This approach is provided by a virtual metrology module (VM) that we have developed and which can be integrated into an R2R control loop. The obtained results were validated on academic examples and on real data provided by our partner STMicroelectronics of Rousset from a chemical mechanical planarization (CMP) process. This real data also enabled the results obtained from the virtual metrology to be validated and then supplied to the R2R regulators (who need the estimation of these data).
2

Time and statistical information utilization in high efficiency sub-micron CMOS successive approximation analog to digital converters

Guerber, Jon 07 January 2014 (has links)
In an industrial and consumer electronic marketplace that is increasingly demanding greater real-world interactivity in portable and distributed devices, analog to digital converter efficiency and performance is being carefully examined. The successive approximation (SAR) analog to digital converter (ADC) architecture has become popular for its high efficiency at mid-speed and resolution requirements. This is due to the one core single bit quantizer, lack of residue amplification, and large digital domain processing allowing for easy process scaling. This work examines the traditional binary capacitive SAR ADC time and statistical information and proposes new structures that optimize ADC performance. The Ternary SAR (TSAR) uses the quantizer delay information to enhance accuracy, speed and power consumption of the overall SAR while providing multi-level redundancy. The early reset merged capacitor switching SAR (EMCS) identifies lost information in the SAR subtraction and optimizes a full binary quanitzer structure for a Ternary MCS DAC. Residue Shaping is demonstrated in SAR and pipeline configurations to allow for an extra bit of signal to noise quantization ratio (SQNR) due to multi-level redundancy. The feedback initialized ternary SAR (FITSAR) is proposed which splits a TSAR into separate binary and ternary sub-ADC structures for speed and power benefits with an inter-stage encoding that not only maintains residue shaping across the binary SAR, but allows for nearly optimally minimal energy consumption for capacitive ternary DACs. Finally, the ternary SAR ideas are applied to R2R DACs to reduce power consumption. These ideas are tested both in simulation and with prototype results. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from Jan. 7, 2013 - Jan. 7, 2014
3

Uma abordagem para a geração semiautomática de mapeamentos R2R baseado em um catálogo de padrões / An approach for the semi-automatic generation of R2R mapping based on a pattern catalog

Vinuto, Tiago da Silva January 2017 (has links)
VINUTO, Tiago da Silva. Uma abordagem para a geração semiautomática de mapeamentos R2R baseado em um catálogo de padrões. 2017. 79 f. Dissertação (Mestrado em Ciência da Computação)-Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Jonatas Martins (jonatasmartins@lia.ufc.br) on 2017-06-14T19:34:12Z No. of bitstreams: 1 2017_dis_tsvinuto.pdf: 2564152 bytes, checksum: 69c006c65896f3b88eebdf993810f56a (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2017-06-22T19:34:26Z (GMT) No. of bitstreams: 1 2017_dis_tsvinuto.pdf: 2564152 bytes, checksum: 69c006c65896f3b88eebdf993810f56a (MD5) / Made available in DSpace on 2017-06-22T19:34:26Z (GMT). No. of bitstreams: 1 2017_dis_tsvinuto.pdf: 2564152 bytes, checksum: 69c006c65896f3b88eebdf993810f56a (MD5) Previous issue date: 2017 / The web of linked data has grown considerably in recent years and covers a wide range of different domains today (BIZER; JENTZSCH; CYGANIAK, 2011). Linked data sources use different vocabularies to represent data about a specific type of object. For example, DBpedia 3 and Music ontology 4 use their proprietary vocabularies to represent data About musical artists. Translating data from these bound data sources into the vocabulary that is expected by a linked data application requires a large number of mappings and may require many structural transformations as well as complex transformations in the property value. Several tools emerge to map ontologies such as the SPARQL 1.1 language, LDIF framework and the Mosto tool. We choose to use in our study the R2R language, which was pointed out in (BIZER et al., 2012) as a good option to map ontologies, as it stands out in terms of expressiveness and performance. The R2R mapping language is a language based on the SPARQL language that allows you to transform data from a source vocabulary into a user-defined target vocabulary. However, defining mappings using this language is complex and subject to several types of errors, such as writing errors or even semantic errors, requiring expect user most to define the mappings. In this scenario, we propose an approach, using mapping patterns to automatically generate R2R mappings from a AMs. The approach is divided into two steps: (1) the manual specification of a set of AMs between the vocabulary of a source ontology and the vocabulary of a target ontology of the user’s choice; and (2) the automatic generation of the R2R mappings based on the result of the first step. Finally, we present the R2R By Assertions tool to help the user in the process of generating R2R mapping. / A Web de dados ligados tem crescido consideravelmente nos últimos anos e abrange uma vasta gama de domínios diferentes hoje (BIZER; JENTZSCH; CYGANIAK, 2011). Fontes de dados ligados usam diferentes vocabulários para representar dados sobre um tipo específico de objeto. Como por exemplo, DBpedia e Music ontology que usam seus vocabulários proprietários para representar dados sobre artistas musicais. Traduzir dados dessas fontes de dados para o vocabulário que é esperado por uma aplicação requer um grande número de mapeamentos e pode exigir muitas transformações estruturais, bem como transformações complexas no valor da propriedade. Diversas tecnologias despontam no sentido de traduzir ou mapear ontologias como, a linguagem SPARQL 1.1, a ferramenta Mosto e o framework R2R. Dentre estas escolhemos utilizar em nosso estudo a linguagem R2R, apontada em (BIZER et al., 2012) como uma boa opção para mapear ontologias, pois se destaca em termos de expressividade e desempenho. A linguagem de mapeamento R2R é uma linguagem baseada, na linguagem SPARQL, que permite transformar dados de um vocabulário de origem em um vocabulário de destino definido pelo usuário. Contudo, a construção de mapeamentos utilizando essa linguagem é complexa e sujeita a diversos tipos de erros, tais como erros de escrita ou até mesmo erros semânticos, exigindo do usuário experiência para definir os mapeamentos. Diante deste cenário, propomos uma estratégia, usando padrões de mapeamento, para gerar automaticamente mapeamentos R2R a partir de Assertivas de Mapeamentos (AMs). Nossa abordagem é dividida em duas etapas: (1) a especificação manual de um conjunto de AMs entre o vocabulário de uma ontologia fonte e do vocabulário de uma ontologia alvo de escolha do usuário; e (2) a geração automática dos mapeamentos R2R com base no resultado do primeiro passo. Por último nós apresentamos a ferramenta R2R By Assertions para ajudar o usuário no processo de geração de mapeamentos R2R.
4

Lamination of Organic Solar Modules

Kalldin, Sofie January 2014 (has links)
As the Worlds energy demand is increasing we need more of our energy to be generated from resources that affect the climate as little as possible. Solar power could be the solution if there were solar panels with a less energy demanding production than the established silicon based solar modules. Printable organic solar cells will enable a cheap production process, thus they are mainly made out of polymers in solution. However, to be able to decrease the total cost of the solar modules the commonly used indium tin oxide (ITO) for the transparent electrode needs to be replaced by a less expensive material. If the cheap, high conductive and transparent polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) could replace ITO the cost of organic solar modules would significantly decrease. For PEDOT:PSS to be able to replace ITO there are requirements that have to be met. The transparent electrode needs to be apart from transparent, highly conductive, have a low contact resistance to the other materials in the organic solar cell and be printable. In this study it has been shown that the PEDOT:PSS film with Zonyl and Diethylene Glycol (DEG) as an secondary dopant, is capable of laminating to thin films made out of PEDOT:PSS, metal or a polymer fullerene blend. The contact resistances between two PEDOT:PSS films and PEDOT:PSS film and a metal film proved to be low. When laminating to a metal film an interlayer of Silver Nano Wires (AgNW) was needed to achieve a low contact resistance.
5

CMOS RF SOC Transmitter Front-End, Power Management and Digital Analog Interface

Leung, Matthew Chung-Hin 19 May 2008 (has links)
With the growing trend of wireless electronics, frequency spectrum is crowded with different applications. High data transfer rate solutions that operate in license-exempt frequency spectrum range are sought. The most promising candidate is the 60 GHz multi-giga bit transfer rate millimeter wave circuit. In order to provide a cost-effective solution, circuits designed in CMOS are implemented in a single SOC. In this work, a modeling technique created in Cadence shows an error of less than 3dB in magnitude and 5 degree in phase for a single transistor. Additionally, less than 3dB error of power performance for the PA is also verified. At the same time, layout strategies required for millimeter wave front-end circuits are investigated. All of these combined techniques help the design converge to one simulation platform for system level simulation. Another aspect enabling the design as a single SOC lies in integration. In order to integrate digital and analog circuits together, necessary peripheral circuits must be designed. An on-chip voltage regulator, which steps down the analog power supply voltage and is compatible with digital circuits, has been designed and has demonstrated an efficiency of 65 percent with the specific area constraint. The overall output voltage ripple generated is about 2 percent. With the necessary power supply voltage, gate voltage bias circuit designs have been illustrated. They provide feasible solutions in terms of area and power consumption. Temperature and power supply sensitivities are minimized in first two designs. Process variation is further compensated in the third design. The third design demonstrates a powerful solution that each aspect of variations is well within 10%. As the DC conditions are achieved on-chip for both the digital and analog circuits, digital and analog circuits must be connected together with a DAC. A high speed DAC is designed with special layout techniques. It is verified that the DAC can operate at a speed higher than 3 Gbps from the pulse-shaping FIR filter measurement result. With all of these integrated elements and modeling techniques, a high data transfer rate CMOS RF SOC operating at 60 GHz is possible.
6

Μελέτη και σχεδίαση γραμμικού digital to analog converter

Χρίστου, Χρίστος, Τιμοθέου, Τιμόθεος 31 May 2010 (has links)
Στην παρούσα Διπλωματική Εργασία μελετάται η δομή και τα χαρακτηριστικά ενός νέου μετατροπέα ψηφιακού σήματος σε αναλογικό (Digital to Analog Converter DAC). Η δομή του DAC βασίζεται στη γνωστή δομή του συμβατικού R2R Ladder και θα μπορούσε να θεωρηθεί σαν μία δισδιάστατη ανάπτυξη του Ladder. Αυτό σημαίνει ότι η νέα μορφή του DAC χρησιμοποιεί σαφώς περισσότερες αντιστάσεις από τον συμβατικό Ladder, όμως δίνεται η δυνατότητα της ρύθμισης του ρεύματος εξόδου του κάθε κλάδου. Αυτό έχει ως συνέπεια τη δραματική βελτίωση της γραμμικότητας του DAC. Επιπλέον στην Εργασία αυτή μελετήθηκαν με χρήση της θεωρίας των πιθανοτήτων τα χαρακτηριστικά του απλού Ladder και χρησιμοποιήθηκαν για την εξαγωγή συμπερασμάτων που αφορούν στη γραμμικότητα της νέας δομής Ladder. Τα θεωρητικά αποτελέσματα επιβεβαιώθηκαν με εξομοιώσεις. Τέλος, μία σχεδίαση σε φυσικό επίπεδο με την χρήση μόνο MOSFETS και CMOS τεχνολογίας (χωρίς την χρήση αντιστάσεων) σχεδιάσθηκε και εξομοιώθηκε στο Cadence ένας Ladder της νέας δομής. / This Diploma Thesis studies on a new Digital to Analog Converter (DAC) structure developed in the Applied Electronics Laboratory of the University of Patras. The new DAC structure is based on the simple R2R ladder combining several of them in a 2-dimentional grid. As result a high linearity DAC is derived after a simple calibration procedure. The Diploma Thesis presents results on probability of the simple R2R Ladder, employs these results so as to forecast the linearity of the 2-dimentional Ladder, whereas confirms theoretical results with simulations. Finally, a DAC based on the 2-dimentional topology has been designed and simulated using Cadence, in the framework of this Diploma Thesis.
7

Production of platinum poor electrodes for PEMFC by electrochemical deposition

Werwein, Anton, Kunz, Karina, Reuber, Sebastian, Weiser, Mathias, Goldberg, Adrian, Partsch, Mareike, Michaelis, Alexander 27 May 2022 (has links)
A new R2R capable process to produce platinum-poor fuel cells was presented in the lab scale. Platinum particles were deposited electrochemically on a mesoporous carbon carrier with various carbon carriers (Super P Li, Denka Black Li 400, Denka Black Li 435, Ketjenblack EC300). FESEM images showed particles in the range of 50 nm one the electrode surface. The catalyst containing electrodes were transferred via hot press from different metallic and polymeric decal materials on a polymer exchange membrane. First functional membrane electrode assemblies show the proof-of-principles of this new process. / Ein neuer R2R-fähiger Prozess für die Herstellung platinumarmer Brennstoffzellen wurde im Labormaßstab etabliert. Platinumpartikel wurde elektrochemisch auf einen mesoporösen Kohlenstoffträger mit verschieden Leitrußen (Super P Li, Denka Black Li 400, Denka Black Li 435, Ketjenblack EC300) abgeschieden. FESEM-Aufnahmen zeigen Partikel in der Größenordnung von 50 nm auf der Elektrodenoberfläche. Die katalysatorhaltige Elektrode wird mittels eines Heißpressverfahren auf eine Polymeraustauschmembran übertragen. Erste funktionsfähige Membran-Elektroden-Assemblierungen zeigen die Funktionsfähigkeit des Prozesses.
8

CdS nanocrystalline thin films deposited by the continuous microreactor-assisted solution deposition (MASD) process : growth mechanisms and film characterizations

Su, Yu-Wei 08 June 2011 (has links)
The continuous microreactor-assisted solution deposition (MASD) process was used for the deposition of CdS thin films on fluorine-doped tin oxide (FTO) glass. The MASD system, including a T-junction micromixer and a microchannel heat exchanger is capable of isolating the homogeneous particle precipitation from the heterogeneous surface reaction. The results show a dense nanocrystallite CdS thin films with a preferred orientation at (111) plane. Focused-ion-beam was used for TEM specimen preparation to characterize the interfacial microstructure of CdS and FTO layers. The band gap of the microreactor-assisted deposited CdS film was determined at 2.44 eV. X-ray Photon Spectroscopy show the bindings of energies of Cd 3d₃/₂, Cd 3d₅/₂, S 2p₃/₂ and S 2p₁/₂ at 411.7 eV, 404.8 eV, 162.1 eV, and 163.4 eV, respectively. The film growth kinetics was studied by measuring the film thickness deposited from 1 minute to 15 minutes in physical (FIB-TEM) and optical (reflectance spectroscopy) approaches. A growth model that accounts for the residence time in the microchannel using empirical factor (η) obtained from previous reported experimental data. Applying this factor in the proposed modified growth model gives a surface reaction rate of 1.61*10⁶ cm⁴ mole⁻¹s⁻¹, which is considerable higher than the surface reaction rates obtained from the batch CBD process. With the feature of separating homogeneous and heterogeneous surface reaction, the MASD process provides the capability to tailor the surface film growth rate and avoid the saturation growth regime in the batch process. An in situ spectroscopy technique was used to measure the UV-Vis absorption spectra of CdS nanoparticles formed within the continuous flow microreactor. The spectra were analyzed by fitting the sum of three Gaussian functions and one exponential function in order to calculate the nanoparticle size. This deconvolution analysis shows the formation of CdS nanoparticles range from 1.13 nm to 1.26 nm using a residence time from 0.26 s to 3.96 s. Barrier controlled coalescence mechanism seems to be a reasonable model to explain the experimental UV-Vis data obtained from the continuous flow microreactor, with a rate constant k' value of 2.872 s⁻¹. Using CFD, low skewness value of the RTD curve at high flow rate (short τ) suggests good radial mixing at high flow rate is responsible for the formation of smaller CdS nanoparticles with a narrower size distribution. The combination of CdS nanoparticle solution with MASD process resulted in the hindrance of CdS thin film deposition. It is hypothesized that the pre-existing sulfide (S²⁻) ions and CdS nanoparticles changes the chemical species equilibrium of thiourea hydrolysis reaction. Consequently, the lack of thiourea slows down the heterogeneous surface reaction. To test the scalability of the MASD process, a flow cell and reel-to-reel (R2R)-MASD system were setup and demonstrated for the deposition of CdS films on the FTO glass (6" x 6") substrate. The film deposition kinetics was found to be sensitive to the flow conditions within the heat exchanger and the substrate flow cell. The growth kinetics of the CdS films deposited by R2R-MASD process was investigated by with a deposition time of 2.5 min, 6.3 min, and 9 min. In comparison with the continuous MASD process, the growth rate in R2R-MASD is higher, however more difficult to obtain a linear relationship with the deposition time. / Graduation date: 2012 / Access restricted to the OSU Community at author's request from Jan. 13, 2012 - Jan. 13, 2013
9

DESIGN AND FABRICATION OF FLEXIBLE SENSORS FOR SINGLE-USE APPLICATIONS

Aiganym Yermembetova (13954878) 13 October 2022 (has links)
<p>The development of reliable, robust and low-cost sensor devices is growing in importance and an ongoing challenge. From environmental monitoring and household safety to food and biopharmaceutical industries, the necessity for specific analyte detection is crucial. Over the years researchers have come up with myriad materials that can be used for efficient sensing devices. The materials employed are governed by application and performance criteria as well as the sensing mechanism, which might be based on physical or chemical principles. In this thesis, two different types of electrochemical sensor technologies were examined with special attention paid to the application of the devices, the materials used, and their feasibility for scalable manufacturing.</p> <p>In the first study, binary mixtures of conducting and semiconducting nanomaterials were explored as promising candidates for the manufacturing of low-cost ethylene sensor on flexible substrates. Ethylene (C2H4) is a small plant hormone which has been shown to affect the growth and senescence of flowers, leaves and fruits. Currently available devices have demonstrated high ethylene sensitivities with great potential for technology size reduction; however, some are not practical for use outside of the laboratory, lack portability, or require more research to demonstrate their reproducibility and stability in different environments, as well as selectivity to C2H4 in large-scale applications. Conductometric gas sensors based on a combination of carbon nanotubes (CNTs) and exfoliated molybdenum disulfide (MoS2) coated with molecular receptors is demonstrated for the selective detection of ethylene, including details on materials preparation, manufacturing, and characterization. Mixtures of CNTs and exfoliated MoS2 were deposited onto screen-printed interdigitated electrodes on plastic substrates, with optimization for scalable and continuous manufacturing by roll-to-roll methods. C2H4 detection levels of 0.1 ppm were readily achieved with responses on the second timescale.</p> <p>The second sensor technology shows how thin-film potentiometric electrodes based on ion-selective membranes can be designed to tolerate sterilizing radiation while providing excellent performance and signal stability. This sensor's development was motivated by the expanding need for single-use bioreactor systems in the biopharmaceutical industry, which require strict control over cell culture conditions for several weeks or more. Until recently, critical analysis has been conducted mostly by offline or “at-line” sampling of aliquots withdrawn from the sterile bioreactor. The latter is inefficient and can increase the risk of contamination. Inspired by the challenges related to cost, integration and performance following irradiation a potentiometric pH electrode was developed, intended for single-use applications. It was shown to be radiation-tolerant while providing reliable data comparable to a commercial pH meter over a period of three months. The electrodes exhibited quasi-linear signal drifts of +0.28 mV/day or 0.005 pH units/day. Thin-film γ-irradiated electrodes could provide accurate pH readings in sterilized culture media using a single-point calibration, within 0.07 pH units of a commercial meter with glass electrode and daily calibration. Furthermore, to advance the development of market-ready sensors past the conceptual stage, a few automated processes for scalable membrane deposition were investigated.</p>

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