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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.
121

The Company of Animals: a Nontoxic Approach.

Boochard, Bonnie K. Foss 01 May 2001 (has links) (PDF)
This document investigates the concept of why man creates animal images and introduces the influences and focus of the artwork contained in the public exhibition. These original images focus on the similarities between animal and human personalities. Also included is a brief history of each "ink on paper" printmaking process used and a comparison of the results. All of the techniques discussed generally have a photographic process as their basis and use personal photographs and drawings for the foundation of each original print. In conclusion, areas for growth, enhancement, and future work are discussed, including a summary of the personal insights gained through the body of work. This thesis also supports the visual exhibition in the B. Carroll Reece Museum, East Tennessee State University, in fulfillment of the Master of Fine Arts degree.
122

Process Development For The Fabrication Of Mesoscale Electrostatic Valve Assembly

Dhru, Shailini Rajiv 01 January 2007 (has links)
This study concentrates on two of the main processes involved in the fabrication of electrostatic valve assembly, thick resist photolithography and wet chemical etching of a polyamide film. The electrostatic valve has different orifice diameters of 25, 50, 75 and 100 µm. These orifice holes are to be etched in the silicon wafer with deep reactive ion etching. The photolithography process is developed to build a mask of 15 µm thick resist pattern on silicon wafer. This photo layer acts as a mask for deep reactive ion etching. Wet chemical etching process is developed to etch kapton polyamide film. This etched film is used as a stand off, gap between two electrodes of the electrostatic valve assembly. The criterion is to develop the processed using standard industry tools. Pre post etch effects, such as, surface roughness, etching pattern, critical dimensions on the samples are measured with Veeco profilometer.
123

Fabrication of Multi-Parallel Microfluidic Devices for Investigating MechanicalProperties of Cancer Cells

Chopra, Pooja 19 September 2016 (has links)
No description available.
124

Elaboration et caractérisation de matériaux hybrides organiques - inorganiques : application à l’optique ophtalmique / Preparation and characterization of hybrid organic - inorganic materials : application to ophthalmic optics

Courson, Rémi 22 April 2011 (has links)
Cette thèse s'inscrit dans le projet optique digital porté par la société Essilor, leader mondial dans le domaine de l'optique ophtalmique. La collaboration entre le laboratoire Charles Coulomb et Essilor a donné naissance à une nouvelle génération de systèmes optiques apposés directement sur le verre ophtalmique. Ce système est constitué de microcuves remplies d'un autre matériau pouvant être différent d'une cuve à l'autre. Il en résulte une pixellisation de la surface permettant des phénomènes optiques innovants. La première partie de ce travail est consacrée à la synthèse et à la caractérisation de résines hybrides organiques-inorganiques photosensibles fonctionnant à différentes longueurs d'ondes. Le but est de créer les microcuves par un procédé de photolithographie dont la rigidité est telle que les murs puissent résister au remplissage par un liquide. Les polymérisations minérales et organiques de ces résines ont été étudiées d'un point de vue structural (spectroscopie infrarouge et RMN), mécanique (technique de nanoindentation) et texturale (absorption - désorption de gaz). La deuxième partie porte sur l'incorporation d'une couche ultraporeuse à l'intérieur des microcuves. Le choix final s'est porté sur un aérogel de silice mélangé à un polymère et réalisé par séchage en condition supercritique du CO2. Ses propriétés sont caractérisées par diverses techniques comme le MEB, les spectroscopies infrarouge et UV-Visible, la microscopie AFM et la nanoindentation. Ce système constitué de microcuves remplies d'un matériau ultraporeux peut alors être imprégné localement par différents liquides d'indice de réfraction variés afin d'obtenir les effets optiques désirés. / This thesis is feeling part of the optical digital project carried out by Essilor, the world leader in the ophthalmic optics field. The collaboration between the Charles Coulomb Laboratory (LCC) and Essilor has spawned a new generation of optical systems affixed directly on the ophthalmic glass. This system consists of microtanks filled with material that may be different from one tank to the other. The result is a pixelated surface which can be lead to innovative optical phenomena. The first part of this work is devoted to the synthesis and characterization of photosensitive organic-inorganic hybrid resins operating at different wavelengths. The goal is to create by a photolithography process microtanks whose rigidity is such that the walls can resist with a liquid filling. Polymerizations of hybrid photosensitive resins have been studied in a structural (infrared and NMR spectroscopy), mechanical (nanoindentation technique) and textural (absorption - desorption of gas) way. The second part focuses on the ultraporous layer incorporation inside microtanks. The final choice fell on silica aerogel containing polymer and obtained under CO2 supercritical drying conditions. Its properties are characterized by various techniques such as SEM, infrared and UV-Visible spectroscopy, AFM microscopy and nanoindentation technique. The all system consists of microtanks filled with an ultraporous material which can be locally impregnated by different liquids with a varied refractive index to obtain the desired optical effects.
125

Optimisation d'une structure résonante pour la réalisation d'un coupleur coplanaire miniature / Optimization of a resonator for the realization of a miniaturised coplanar coupler

Melhem, Zeina 09 November 2012 (has links)
Les systèmes de télécommunications requièrent de plus en plus l’utilisation des composants passifs hyperfréquences. La commercialisation de ces composants nécessite la miniaturisation de leurs tailles, l’augmentation de leurs performances et la réduction de leurs coûts. Parmi ces composants passifs, nous citons le coupleur directionnel qui est un quadripôle destiné à répartir la puissance sur deux ports de sortie, le quatrième port reste isolé. Les travaux relatés dans ce manuscrit ont pour objectifs la conception et la réalisation d’un coupleur à accès coplanaires obtenu à partir d’un résonateur auquel nous avons appliqué des lignes de couplage. Un modèle équivalent approché a été mis en évidence par un logiciel de simulation circuit. Une étude paramétrique a été réalisée à l’aide d’un logiciel électromagnétique 3D pour fixer une règle de conception qui permet un dimensionnement convenable du composant pour un intervalle de fréquences prédéfinies. Un fonctionnement bi-bandes a été exploité pour chaque raccordement de la fréquence. Une deuxième structure de couplage a été déduite en reliant directement les lignes couplées sur le résonateur. Une étude paramétrique ainsi qu’une règle de conception ont mis en évidence un fonctionnement de coupleur mono-bande de cette structure à des fréquences prédéfinies. Une troisième structure qui fonctionne en coupleur a été exploitée en remplaçant le filtre résonateur par deux circuits en méandres. Ce nouveau coupleur à méandres présente des bandes passantes assez larges ainsi qu’un fonctionnement possible en bi-bandes. Ces coupleurs mis en œuvre peuvent assurer un couplage de l’ordre de 3 ; 6 ; 8 et 10 dB et d’un déphasage entre les deux ports de sortie de 180° pour les deux premières structures et de 90° pour le coupleur à méandres. Plusieurs séries de prototypes sont ensuite fabriquées à partir des structures optimisées en simulation. Les caractérisations hyperfréquences de ces composants montrent la performance des dispositifs réalisés / Telecommunications systems require more use of passive microwave components. The commercialization of these components requires the miniaturization of their size, increasing their performance and the reduction of their costs. Among these passive components we cited the directional coupler which is designated to spread the power between two outputs, the fourth port being isolated. The ambition of this work is to study and fabricate a coupler with coplanar access obtained from a resonator where we applied coupling lines. An equivalent approximate model was obtained using circuit simulation software. A parametric study was made using 3D electromagnetic software to fix a design rule that allows a suitable design for the component in a predefined frequency range. Dual-band operation has been exploited for each frequency. A second coupling structure was deduced by directly connecting the coupled lines to the resonator. A parametric study and a design rule have shown the operation of this structure as a single band coupler at predefined frequencies. A third structure which operates like a coupler has been exploited by replacing the resonator filter by two meandering circuits. This new meandering coupler presents a wide bandwidth and a possible operating in dual-band. These implemented couplers provided a coupling factor of 3, 6, 8 and 10 dB and a phase shift between the two output ports of 180° for the two first structures and a 90° phase shifter for the meandering coupler. Several sets of prototypes are then made. The microwave characterizations show the performance of the fabricated device
126

SAT based environment for logical capacity evaluation of via configurable block templates

Dal Bem, Vinícius January 2016 (has links)
ASICs estruturados com leiautes regulares representam uma das soluções para a perda de rendimento de fabricação de circuitos integrados em tecnologias nanométricas causada pela distorção de fotolitografia. Um método de projeto de circuitos integrados ainda mais restritivo resulta em ASICs estruturados configuráveis apenas pelas camadas de vias, que são compostos pela repetição do mesmo modelo de bloco em todas as camadas do leiaute, exceto as camadas de vias. A escolha do modelo de bloco tem grande influência nas características do circuito final, criando a demanda por novas ferramentas de CAD que possam avaliar e comparar tais modelos em seus diversos aspectos. Esta tese descreve um ambiente de CAD baseado em SAT, capaz de avaliar o aspecto de capacidade lógica em padrões de blocos configuráveis por vias. O ambiente proposto é genérico, podendo tratar quaisquer padrões de bloco definido pelo usuário, e se comporta de maneira eficiente quando aplicado aos principais padrões já publicados na literatura. / Structured ASICs with regular layouts comprise a design-based solution for IC manufacturing yield loss in nanometer technologies caused by photolithography distortions. Via-configurable structured ASICs is even a more restrictive digital IC design method, based on the repetition of a block template comprising all layout layers except the vias one. The choice of such a design strategy impacts greatly the final circuit characteristics, arising the need for specific CAD tools to allow template evaluation and comparison in different aspects. This work presents a SAT-based CAD environment for evaluating the logical capacity aspect of via-configurable block templates. The proposed environment is able to support any user-defined template, and behaves efficiently when applied to block templates presented in related literature.
127

Design, Manufacture, and Structural Dynamic Analysis of a Biomimetic Insect-Sized Wing for Micro Air Vehicles

Rubio, Jose Enrique 20 December 2017 (has links)
The exceptional flying characteristics of airborne insects motivates the design of biomimetic wing structures that can exhibit a similar structural dynamic behavior. For this purpose, this investigation describes a method for both manufacturing a biomimetic insect-sized wing using the photolithography technique and analyzing its structural dynamic response. The geometry of a crane fly forewing (family Tipulidae) is acquired using a micro-computed tomography scanner. A computer-aided design model is generated from the measurements of the reconstructed scanned model of the insect wing to design the photomasks of the membrane and the venation network required for the photolithography procedure. A composite material wing is manufactured by patterning the venation network using photoresist SU-8 on a Kapton film for the assembling of the wing. A single material artificial wing is fabricated using the photoresist SU-8 for both the membrane and the network of veins. Experiments are conducted using a modal shaker and a digital image correlation (DIC) system to determine the natural frequencies and the mode shapes of the artificial wing from the fast Fourier transform of the displacement response of the wing. The experimental results are compared with those from a finite element (FE) model of the wing. A numerical simulation of the fluid-structure interaction is conducted by coupling the FE model of the artificial wing with a computational fluid dynamics model of the surrounding airflow. From these simulations, the deformation response and the coefficients of drag and lift of the artificial wing are predicted for different freestream velocities and angles of attack. Wind-tunnel experiments are conducted using the DIC system to determine the structural deformation response of the artificial wing under different freestream velocities and angles of attack. The vibration modes are dominated by a bending and torsional deformation response. The deformation along the span of the wing increases nonlinearly from the root of the wing to the tip of the wing with Reynolds number. The aerodynamic performance, defined as the ratio of the coefficient of lift to the coefficient of drag, of the artificial wing increases with Reynolds number and angle of attack up to the critical angle of attack.
128

Étude de composites conducteurs et semi-conducteurs : transducteurs électrochimiques pour biocapteurs / Study of conducting and semiconducting composites : electrochemical transducers for biosensors

Benlarbi, Mouhssine 12 June 2012 (has links)
Ce travail a permis dans un premier temps, l’élaboration de composites semi-conducteurs à base de nanoobjetspossédant des caractéristiques électrochimiques spécifiques en fonction du type d’inclusion (siliciumdopé N ou dopé P et oxydes métalliques, ZnO, SnO2, NiO). Ces composites ont permis d’obtenir avec succèsdes encres de sérigraphie présentant un comportement électrique semi-conducteur qui ont servi à laréalisation d’électrodes par dépôt sur divers supports et notamment des films plastiques souples. Lamodification chimique des supports réalisés a été étudiée en vue de pouvoir utiliser ce type de matériaucomme transducteurs électrochimiques en les intégrant dans des dispositifs de types capteurs et biocapteurs.Dans un second temps, un composite photostructurable conducteur a également été développé en se basantsur la technologie SU-8, et en y incluant des particules de graphite ou des nanoparticules de carbone noir.Ce photocomposite a été par la suite fonctionnalisé avec succès par des dérivés diazonium, tel que lebromobenzène diazonium ou le nitrobenzène diazonium dont les greffages ont été suivis par spectroscopied’impédance. Enfin, le greffage d’oligonucléotides via la chimie des sels d’aryldiazonium a également étéeffectué avec succès et utilisé pour la détection de séquences cibles à des concentrations de 100 pM à 200nM. / The first part of this study report the development of semiconducting composites consisting ofsemiconducting nano-objects (N doped, P doped silicon or metals oxides, ZnO, SnO2, NiO) held together inan insulating polymeric matrix and exhibiting typical semiconductor impedance signals according to thecharge used and with clear differentiation between the two fundamental type of semiconductor, n-type and ptype.This new composites have been used as screen-printing ink. Electrodes on various substrates (PVC,glass) have been successfully prepared following this cost-effective method. Surface functionalization ofthese electrodes by chemicals compounds and biomolecules was studied using impedance spectroscopy andchemiluminescent detection in order to assess their integration as electrochemical transducers in sensorsand biosensors microdevices.The second part of this work consisted in photopatternable conductive composite elaboration using a simpleand straightforward route based on SU-8 epoxy-based negative photoresist matrix mixed with carbon filler.The electrodes, obtained by the classical photolithography method, and after an electrochemical pretreatment,exhibited very good electrochemical behaviors, opening the path to various electrochemicaldetections and grafting possibilities. Finally, the direct electrografting of biomolecules was demonstratedusing aniline modified oligonucleotide probes. The grafted probes were shown to be available for targethybridization and the material compatible with a chemiluminescent detection of the interactions between theimmobilized single stranded DNA and its complementary sequence in a 100 pM to 200 nM range.
129

Processing and On-Wafer Test of Ferroelectric Film Microwave Varactors

Kim, Jang-Yong January 2006 (has links)
Microwave materials have been widely used in a variety of applications ranging from communication devices to military satellite services, and the study of materials properties at microwave frequencies and the development of functional microwave materials have always been among the most active areas in solid-state physics, materials science, electrical and electronic engineering. In recent years, the increasing requirements for the development of high speed, high frequency circuits and systems require complete understanding of the properties of materials function at microwave frequencies. Ferroelectric materials usually have high dielectric constant, and their dielectric properties are temperature and electric field dependent. The change in permittivity as a function of electric field is the key to a wide range of applications. Ferroelectric materials can be used to fabricate capacitors for electronic industry because of their high dielectric constant, and this is important in the trend toward miniaturization and high functionality of electronic products. The simple tunable passive component based on ferroelectric films is a varactor which can be made as a planar structure and used for electrically tunable microwave integrated circuits. It is an important task to sinter highly tunable and low loss ferroelectrics, fabricate and test the properties of microwave ferroelectric components. This thesis shows experimental results on growth, crystalline and microwave properties of Na0.5K0.5NbO3 (NKN), AgTa0.5Nb0.5O3 (ATN), Ba0.5Sr0.5TiO3 (BST) as well as AgTaO3 (ATO), and AgNbO3 (ANO) thin films. The films were grown by Pulsed Laser Deposition (PLD) and rf-magnetron sputtering techniques from stoichiometric high density ceramic NKN, ATN, ATO, ANO and BST targets onto LaAlO3 (LAO), Al2O3 (r-cut sapphire), Nd:YAlO3 single crystals and amorphous glass substrates. Advanced X-ray diffraction examinations showed NKN, ATN, BST films on LAO substrates grow epitaxially, whereas films on r-cut sapphire were found to be preferentially (00l) oriented. Coplanar waveguide 2 µm finger gap interdigital capacitor (CPWIDC) structures were fabricated by photolithography process and metal lift-off technique. On-wafer tests up to 40 GHz were performed to characterize microwave properties of the ferromagnetic film CPWIDC devices. The measurement setup is composed of network analyzer, probe station, and microwave G-S-G probes. External electric field was applied to planar capacitors to measure tunability. Original de-embedding technique has been developed to calculate capacitance, loss tan δ, and tunability of varactors from the measured S-parameters. NKN film interdigital capacitors on Nd:YAlO3 showed superior performance compared to ATN in the microwave range from 1 to 40 GHz. Within this range, the voltage tunability (40V, 200 kV/cm) was about 29%, loss tangent ~ 0.13, K-factor = tunability/tan δ from 152% @ 10GHz to 46% @ 40GHz. The ATN/sapphire CPWIDCs showed the lowest dispersion ~ 4.3% in whole frequency range from 1 to 40 GHz, voltage tunability 4.7% @ 20GHz and 200 kV/cm, lowest loss tangent ~ 0.068 @ 20GHz, K-factor = tunability/tan δ ranged from 124% @ 10GHz to 35% @ 40GHz. BST film CPWIDCs on sapphire showed frequency about 17%, the highest voltage tunability ~ 22.2%, loss tangent ~ 0.137 @ 20GHz, and K-factor = 281% @ 10GHz to 95% @ 40GHz. / QC 20100906
130

Simulation and process development for ion-implanted N-type silicon solar cells

Ning, Steven 11 April 2013 (has links)
As the efficiency potential for the industrial P-type Al-BSF silicon solar cell reaches its limit, new solar cell technologies are required to continue the pursuit of higher efficiency solar power at lower cost. It has been demonstrated in literature that among possible alternative solar cell structures, cells featuring a local BSF (LBSF) have demonstrated some of the highest efficiencies seen to date. Implementation of this technology in industry, however, has been limited due to the cost involved in implementing the photolithography procedures required. Recent advances in solar cell doping techniques, however, have identified ion implantation as a possible means of performing the patterned doping required without the need for photolithography. In addition, past studies have examined the potential for building solar cells on N-type silicon substrates, as opposed to P-type. Among other advantages, it is possible to create N-type solar cells which do not suffer from the efficiency degradation under light exposure that boron-doped P-type solar cells are subject to. Industry has not been able to capitalize on this potential for improved solar cell efficiency, in part because the fabrication of an N-type solar cell requires additional masking and doping steps compared to the P-type solar cell process. Again, however, recent advances in ion implantation for solar cells have demonstrated the possibility for bypassing these process limitations, fabricating high efficiency N-type cells without any masking steps. It is clear that there is potential for ion implantation to revolutionize solar cell manufacturing, but it is uncertain what absolute efficiency gains may be achieved by moving to such a process. In addition to development of a solar specific ion implant process, a number of new thermal processes must be developed as well. With so many parameters to optimize, it is highly beneficial to have an advanced simulation model which can describe the ion implant, thermal processes, and cell performance accurately. Toward this goal, the current study develops a process and device simulation model in the Sentaurus TCAD framework, and calibrates this model to experimentally measured cells. The study focuses on three main tasks in this regard: Task I - Implant and Anneal Model Development and Validation This study examines the literature in solar and microelectronics research to identify features of ion implant and anneal processes which are pertinent to solar cell processing. It is found that the Monte Carlo ion implant models used in IC fabrication optimization are applicable to solar cell manufacture, with adjustments made to accommodate for the fact that solar cell wafers are often pyramidally textured instead of polished. For modeling the thermal anneal processes required after ion implant, it is found that the boron and phosphorus cases need to be treated separately, with their own diffusion models. In particular, boron anneal simulation requires accurate treatment of boron-interstitial clusters (BICs), transient enhanced diffusion, and dose loss. Phosphorus anneal simulation requires treatment of vacancy and interstitial mediated diffusion, as well as dose loss and segregation. The required models are implemented in the Sentaurus AdvancedModels package, which is used in this study. The simulation is compared to both results presented in literature and physical measurements obtained on wafers implanted at the UCEP. It is found that good experimental agreement may be obtained for sheet resistance simulations of implanted wafers, as well as simulations of boron doping profile shape. The doping profiles of phosphorus as measured by the ECV method, however, contain inconsistencies with measured sheet resistance values which are not explained by the model. Task II - Device Simulation Development and Calibration This study also develops a 3D model for simulation of an N-type LBSF solar cell structure. The 3D structure is parametrized in terms of LBSF dot width and pitch, and an algorithm is used to generate an LBSF structure mesh with this parametrization. Doping profiles generated by simulations in Task I are integrated into the solar cell structure. Boundary conditions and free electrical parameters are calibrated using data from similar solar cells fabricated at the UCEP, as well as data from lifetime test wafers. This simulation uses electrical models recommended in literature for solar cell simulation. It is demonstrated that the 3D solar cell model developed for this study accurately reproduces the performance of an implanted N-type full BSF solar cell, and all parameters fall within ranges expected from theoretical calculations. The model is then used to explore the parameter space for implanted N-type local BSF solar cells, and to determine conditions for optimal solar cell performance. It is found that adding an LBSF to the otherwise unchanged baseline N-type cell structure can produce almost 1% absolute efficiency gain. An optimum LBSF dot pitch of 450um at a dot size of 100um was identified through simulation. The model also reveals that an LBSF structure can reduce the fill factor of the solar cell, but this effect can be offset by a gain in Voc. Further efficiency improvements may be realized by implementing a doping-dependent SRV model and by optimizing the implant dose and thermal anneal. Task III - Development of a Procedure for Ion Implanted N-type LBSF Cell Fabrication Finally, this study explores a method for fabrication of ion-implanted N-type LBSF solar cells which makes use of photolithographically defined nitride masks to perform local phosphorus implantation. The process utilizes implant, anneal, and metallization steps previously developed at the UCEP, as well as new implant masking steps developed in the course of this study. Although an LBSF solar cell has not been completely fabricated, the remaining steps of the process are successfully tested on implanted N-type full BSF solar cells, with efficiencies reaching 20.0%.

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