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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.
431

La lithographie en Bretagne (1819-1914) / The Lithography in Brittany 1819-1914

Benoit-Renault, Viviane 16 December 2014 (has links)
Dans l’histoire de l’estampe, l’étude de la lithographie en province a longtemps été négligée et les premierstravaux fondateurs datent seulement d’une quarantaine d’années. L’objet de cette thèse en histoire de l’art est decombler cette lacune en analysant, dans un esprit d’interdisciplinarité ouvert à l’histoire économique et sociale, lalithographie en Bretagne historique de 1819 à 1914.Cette recherche s’appuie d’abord sur l’étude de l’imprimerie lithographique. Après un panorama généralsur l’évolution du nombre d’ateliers et leur répartition géographique, les centres lithographiques principaux etsecondaires sont étudiés. L’imprimerie autographique qui, en parallèle, s’implante et concurrence les atelierslithographiques est analysée, comme les imprimeries lithographiques sur fer-blanc, une particularité bretonne.Au-delà de cette étude historique, le chapitre suivant dresse le portrait des acteurs de l’imprimerie et de laproduction lithographique comme leur environnement social. C’est un monde où se mêlent l’artiste peintre,l’artiste lithographe de profession, l’amateur de dessin, l’imprimeur et l’ouvrier. La réalité du monde de l’estampeest abordée dans le troisième chapitre, avec un coup de projecteur sur l’atelier et sur l’histoire matérielle de lalithographie (presses et matrices). L’atelier est ensuite appréhendé comme un espace de vie autonome avec sesfêtes et ses codes, garants de la cohésion ouvrière. Une unité renforcée avec la création des syndicats delithographes dans la seconde moitié du XIXe siècle.Grâce à l’établissement d’un inventaire des lithographies, fondé sur le dépouillement du dépôt légal etdes fonds publics d’estampes, l’analyse de la production lithographique imprimée en Bretagne révèle unediversité thématique insoupçonnée. La lithographie artistique à la feuille, en recueils ou en albums illustrés estanalysée sous l’angle stylistique et iconographique. Enfin, l’étude de la lithographie utilitaire et des boîtes en ferblanclithographié clôt ce chapitre. Le commerce de l’estampe, qui constitue le dernier maillon du circuit de laproduction, est retracé avec ses marchands, une profession en mutation au XIXe siècle, ses colporteurs et autresvendeurs occasionnels. Enfin, la question de la diffusion de l’estampe en Bretagne est abordée comme le marchéet la place de la lithographie bretonne dans un réseau national et international. / In the history of print, the study of lithography in province has long been neglected. The first founding worksonly date back to the last forty years. The purpose of this thesis on the history of art is to address this shortcomingby analysing lithography in historical Brittany between 1819 and 1914 bearing an interdisciplinarity mind open toeconomic and social history.Initially this research will be based on the study of lithographic printing. Following a general overviewon the evolution of the number of workshops and their geographical breakdown, leading and secondarylithographic centres are being considered. On the other hand, autographic printing which established itself andcame into competition with the lithographic workshops is being analysed with an emphasis on tin-plate printingworkshops being a characteristic feature of Brittany. Beyond this historical study, the following chapter paints aportrait of the printers and that of the lithographic production scene which being a social environment. It is aworld whereby the painter mingles with the professional lithographer, the drawing lover, the printer and thecraftsman. The reality of the printing world is being addressed in the third chapter with a particular focus on theworkshop and the history of the equipment specific to printing (plates and moulds). Subsequently the workshop isseen as a world in its own right with its celebrations and codes responsible for the working cohesion. This unitywill be accentuated in the second half of the XIX century with the constitution of lithographers unions. Thanksto the creation of a lithographs inventory drawn upon the austerity regarding registration of copyright and printpublic funds, the analysis of the print production in Brittany reveals an unexpected thematic diversity. The artisticprint on sheet, collections or illustrated albums is analysed from a stylistic and iconographic point of view.Finally, the study of useful lithography and the tin-box will bring this chapter to a close.Print trade which formsthe last link in the production chain is recounted through its merchants, a trade being transformed throughout XIXcentury, door-to-door and casual sellers. Lastly, the topic of the diffusion of print in Brittany is put forward asbeing the market place of Breton lithography within a national and international network.
432

Deterministic Silicon Pillar Assemblies and their Photonic Applications

Dev Choudhury, Bikash January 2016 (has links)
It is of paramount importance to our society that the environment, life style, science and amusement flourish together in a balanced way. Some trends in this direction are the increased utilization of renewable energy, like solar photovoltaics; better health care products, for example advanced biosensors; high definition TV or high resolution cameras; and novel scientific tools for better understanding of scientific observations. Advancement of micro and nanotechnologies has directly and positively impacted our stance in these application domains; one example is that of vertical periodic or aperiodic nano or micro pillar assemblies which have attracted significant research and industrial interest in recent years. In particular, Si pillars are very attractive due to the versatility of silicon. There are many potential applications of Si nanopillar/nanowire assemblies ranging from light emission, solar cells, antireflection, sensing and nonlinear optical effects. Compared to bulk, Si pillars or their assemblies have several unique properties, such as high surface to volume ratios, light localization, efficient light guiding, better light absorption, selective band of light propagation etc.      The focus of the thesis is on the fabrication of Si pillar assemblies and hierarchical ZnO nanowires on Si micro structures in top-down and bottom-up approaches and their optical properties and different applications. Here, we have investigated periodic and aperiodic Si nano and micro structure assemblies and their properties, such as light propagation, localization, and selective guiding and light-matter interaction. These properties are exploited in a few important optoelectronic/photonic applications, such as optical biosensors, broad-band anti-reflection, radial-junction solar cells, second harmonic generation and color filters.         We achieved a low average reflectivity of ~ 2.5 % with the periodic Si micropyramid-ZnO NWs hierarchical arrays. Tenfold enhancement in Raman intensity is also observed in these structures compared to planar Si. These Si microstructure-ZnO NW hierarchical structures can enhance the performance and versatility of photovoltaic devices and optical sensors. A convenient top-down fabrication of radial junction nanopillar solar cell using spin-on doping and rapid thermal annealing process is presented. Broad band suppressed reflection, on average 5%, in 300- 850 nm wavelength range and an un-optimized cell efficiency of 6.2 % are achieved. Our method can lead to a simple and low cost process for high efficiency radial junction nanopillar solar cell fabrication.            Silicon dioxide (SiO2) coated silicon nanopillar (NP) arrays are demonstrated for surface sensitive optical biosensing. Bovine serum albumin (BSA)/anti-BSA model system is used for biosensing trials by photo-spectrometry in reflection mode. Best sensitivity in terms of limit of detection of 5.2 ng/ml is determined for our nanopillar biosensor. These results are promising for surface sensitive biosensors and the technology allows integration in the CMOS platform.         Si pillar arrays used for surface second harmonic generation (SHG) experiments are shown to have a strong dependence of the SHG intensity on the pillar geometry. The surface SHG can be suitable for nonlinear silicon photonics, surface/interface studies and optical sensing.         Aperiodic Si nanopillar assemblies in PDMS matrix are demonstrated for efficient color filtering in transmission mode. These assemblies are designed using the ‘‘molecular dynamics-collision between hard sphere’’ algorithm. The designed structure is modeled in a 3D finite difference time domain (FDTD) simulation tool for optimization of color filtering properties. Transverse localization effect of light in our nanopillar color filter structures is investigated theoretically and the results are very promising to achieve image sensors with high pixel densities (~1 µm) and low crosstalk. The developed color filter is applicable as a stand-alone filter for visible color in its present form and can be adapted for displays, imaging, smart windows and aesthetic applications. / <p>QC 20160407</p>
433

Modeling and optimization to connect layout with silicon for nanoscale IC

Shi, Xiaokang 04 June 2010 (has links)
With continuous and aggressive scaling in semiconductor technology, there is an increasing gap between design expectation and manufactured silicon data. Research on DFM (Design for manufacturability), MFD (Manufacturing for Design) and statistical analysis have been investigated in recent years to bridge design and manufacturing. Fundamentally, layout is the final output from the design side and the input to the manufacturing side. It is also the last chance to dramatically modify the design efficiently and economically. In this dissertation, I present the modeling and optimization work on bridging the gap between design expectation and reality, improving performance and enhancing manufacturing yield. I investigate several stages of semiconductor design development including manufacturing process, device, interconnect, and circuit level. In the manufacturing process stage, a novel inverse lithography technology (ILT) is proposed for sub-wavelength lithography resolution enhancement. New intuitive transformations enable the method to gradually converge to the optimal solution. A highly efficient method for gradient calculation is derived based on partially coherent optical models. Dose variation is considered within the ILO process with the min-max optimization method and the computation overhead on dose process variation could be omitted. The methods are implemented in state-of-the-art industrial 32nm lithography environment. After the work in the lithography process stage provides both mask optimization and post-layout silicon image simulation, my work on the first non-rectangular device modeling card extends the post-layout lithography to post-litho electrical calibration. Based on the lithography simulation results, the non-rectangular gate shapes are extracted and their effect is investigated by the proposed non-rectangular device modeling card and post-litho circuit simulation flow. This work is not only the first non-rectangular device modeling card but also compatible with industry standard device models and the parameter extraction flow. Interconnect plays a more critical role in the nanometer scale IC design especially because of its impact on delay. The scattering effect that occurs in nanoscale wires is modeled and different methods of wire sizing/shaping are discussed. Based on closed-form resistivity model for nanometer scale Cu interconnect, new interconnect delay model and wire sizing/shaping strategies are developed. Based on the advanced modeling of process, device and interconnect, circuit level investigation is focused on statistical timing analysis with a new latch delay model. For the first time, both combinational logic and clock distribution circuits are integrated together through statistical timing of latch outputs. This dissertation studies the new phenomena of nanometer scale IC design and manufacture. Starting from the designed layout, through modeling, optimization and simulation, the work moves ahead to the mask pattern and silicon image, calibrates electrical properties of devices as well as circuits. Through above process, we can better connect layout with silicon data to reach design and manufacturing closure. / text
434

Catalysis and materials development in organic chemistry

Berro, Adam Joseph 2009 August 1900 (has links)
The field of organic chemistry is divided into many subfields, which include polymer design and synthesis, transition metal catalysis and organocatalysis among a variety of others. Challenges in polymer design and synthesis can be highlighted pointedly in the use of photoresists for lithographic processing. Recent challenges in development of shorter wavelength sources has led to the need to develop new photoresist materials that can be exposed twice without any development steps in between. Two methods for addressing double exposure materials will be presented. Additionally, the areas of catalysis, whether transition metal or organic in nature, are important methods in organic synthesis. The mechanism of the addition of Gilman reagents to enones has been the subject of debate, and efforts to elucidate this mechanism will be presented. Finally, organocatalysis has expanded its scope into a variety of reactions previously only conducted with transition metal catalysts. Work towards an enantioselective allylic amination reaction using organocatalysis as well as absolute stereochemistry of the product will be explored. / text
435

Feedback Control for Electron Beam Lithography

Yang, Yugu 01 January 2012 (has links)
Scanning-electron-beam lithography (SEBL) is the primary technology to generate arbitrary features at the nano-scale. However, pattern placement accuracy still remains poor compared to its resolution due to the open-loop nature of SEBL systems. Vibration, stray electromagnetic fields, deflection distortion and hysteresis, substrate charging, and other factors prevent the electron-beam from reaching its target position and one has no way to determine the actual beam position during patterning with conventional systems. To improve the pattern placement accuracy, spatial-phase-locked electron-beam lithography (SPLEBL) provides feedback control of electron-beam position by monitoring the secondary electron signal from electron-transparent fiducial grids on the substrate. While scanning the electron beam over the fiducial grids, the phase of the grid signal is analyzed to estimate the electron-beam position error; then the estimates are sent back to beam deflection system to correct the position error. In this way, closed-loop control is provided to ensure pattern placement accuracy. The implementation of spatial-phase-locking on high speed field-programmable gate array (FPGA) provides a low-cost method to create a nano-manufacturing platform with 1 nm precision and significantly improved throughput. Shot-to-shot, or pixel-to-pixel, dose variation during EBL is a significant practical and fundamental problem. Dose variations associated with charging, electron source instability, optical system drift, and ultimately shot noise in the beam itself conspire to increase critical dimension variability and line width roughness and to limit the throughput. It would be an important improvement to e-beam patterning technology if real-time feedback control of electron-dose were provided to improve pattern quality and throughput even beyond the shot noise limit. A novel approach is proposed in this document to achieve the real-time dose control based on the measurement of electron arrival at the sample to be patterned, rather than from the source or another point in the electron-optical system. A dose control algorithm, implementation on FPGA, and initial experiment results for the real-time feedback dose control on the e-beam patterning tool is also presented.
436

Kampinių skalių originalų formavimo stendo sukūrimas ir tyrimas / Design and Research of Angular Scales Originals Forming Stand

Šimkevičius, Artūras 16 June 2014 (has links)
Baigiamojo darbo tikslas – sukurti precizinių kampinių skalių formavimo įrenginį. Darbe yra išanalizuoti kampinių skalių formavimo metodai ir jų realizacijos sistemos, išskirti kampinių skalių formavimo neapibrėžties sandai, suformuoti darbo tikslai, užduotys. Yra išanalizuotos ir ištirtos optimalios įrenginio komponentės. Pasiūlyta įrenginio schema. Nustatyti rastrinių skalių originalų formavimo neapibrėžties atsiradimo dėsningumai. Išskirtos trys pagrindinės paklaidų grupės: judesio, temperatūrinės, kalibravimo. Darbe pateikiama tyrimo metodika – tyrimų eiga, tyriami mazgai ir sistemos, rezultatų apdorojimo metodika. Tyrimo rezultatai pateikti grafiškai, apdoroti statistiniais metodais, apibendrinantys rezultatai apkroksimuoti parametrinėmis funkcijomis. Darbą sudaro 9 dalys: įvadas, problemos analizė ir užduoties formulavimas, precizinių suklių tyrimai, kampo matavimo sistemos kalibravimo tikslumo tyrimas, temperatūrinių gradientų ir jų poveikio tyrimas, linijinių poslinkių matavimų tyrimai, kampinių skalių originalų konstrukcijos parinkimas ir pagrindimas, išvados, literatūros sąrašas. Darbo apimtis – 83 p. teksto be priedų, 55 iliustracijų, 35 bibliografinių šaltinių. Atskirai pridedami priedai. / Final work is dedicated for development of device for precision angular glass scales originals forming. Methods of angular scales forming and their realization have been analyzed. Distinguished angular scales forming elements of uncertainty. Work objectives and tasks have been formed. There are analyzed and researched the optimum device composition. Device scheme is proposed. Angular raster scales forming uncertainty occurrence of patterns determined. Identified three main error groups: motion, temperature and calibration. The work presents research methodology – research process, research components and systems, research data processing techniques. The results are presented graphically and processed by statistical methods, summarized results approximated by parametrical functions. Thesis consists of 9 chapters: introduction, problem analysis and formulation of the task, precision spindle research, angle measuring system accuracy research, temperature gradients and their impact research, linear displacement measurement study, angular scales original forming stand design selection and justification, conclusions, references. Thesis consist of: 83 p. text without appendixes, 55 pictures, 35 bibliographical entries. Appendixes included.
437

Assemblage dirigé de nano-objets / Directed assembly of nano-objects

Cerf, Aline 17 September 2010 (has links)
Un échange vigoureux au travers des frontières de la biologie et de la physique se développe autour de nouvelles méthodes et outils, et autour de nouveaux phénomènes. Les objets d’étude au cœur de ce recouvrement multidisciplinaire sont très divers. De manière non exhaustive, il s’agit de nanoparticules, de cellules ou encore d’objets encore plus petits et élémentaires tels que les molécules. Aussi bien pour des applications dans le domaine de la microélectronique que pour l’étude de mécanismes biologiques fondamentaux, l’intégration des objets d’intérêt à l’échelle de l’objet unique est essentielle. Dans le cadre de cette thèse, l’objectif que nous nous sommes fixés est de développer un volet technologique qui permette l’assemblage d’objets micro- ou nanométriques uniques à des endroits bien définis d’une surface solide de façon simple, fiable, bas-coût et parallèle. Pour ce développement, nous nous sommes intéressés tout particulièrement aux nanoparticules d’Au de 100 nm de diamètre, aux bactéries, puis aux molécules d’ADN. Nous décrirons les stratégies développées reposant sur la lithographie douce puis leurs potentialités pour différentes applications dans les domaines de l’analyse médicale et de la détection. / A vigorous trade across the borders of biological and physical sciences is developing around new methods and tools, and around new phenomena. The objects at the heart of this multidisciplinary overlapping are numerous. In a non exhaustive manner, the objects of study can be nanoparticles, cells, or even smaller and more elementary objects such as molecules. For applications in the field of microelectronics as for studies of fundamental biological mechanisms, the integration of these objects of interest at the single object scale is essential. In the frame of this Ph.D. thesis, the objective we pursued is the development of a technological tool-box allowing the assembly of micro- and nano-objects at pre-determined locations of a solid surface, in a simple, reliable, low-cost and parallel manner. For this development, we focused on gold nanoparticles 100 nm in diameter, bacterial cells and DNA molecules in particular. We will describe the strategies developed relying on soft-lithography and their potentialities for different applications in the fields of medical analysis and sensing.
438

Directional organic light-emitting diodes using photonic microstructure

Zhang, Shuyu January 2014 (has links)
This thesis describes investigations into the optical and device design of organic light-emitting diodes (OLEDs) with the aim of exploring the factors controlling the spatial emission pattern of OLEDs and developing novel OLEDs with directional emission by applying wavelength-scale photonic microstructure. The development of directional OLEDs was broken down into two steps: the development of efficient narrow linewidth OLEDs and the integration of wavelength-scale photonic microstructures into narrow linewidth OLEDs. The narrow linewidth OLEDs were developed using europium (Eu) complexes. The electrical optimisation of solution-processed Eu-based OLEDs using commercially available materials was investigated. The optimised Eu-based OLEDs gave an external quantum efficiency of 4.3% at a display brightness of 100 cd/m². To our knowledge, this is the highest efficiency reported for solution-processed Eu-based OLED devices, and the efficiency roll-off has been reduced compared with other reported references. Photonic microstructures were applied to develop directional OLEDs using the efficient Eu-based OLEDs. Two contrasting strategies were used. One was to embed photonic microstructures into Eu-based OLEDs, the other was to couple photonic microstructures externally onto the devices. The microstructured devices developed by the former strategy boosted the emitted power in desired angles in both s- and p-polarisations and doubled the fraction of emission in an angle range of 4⁰. The devices developed by the external coupling strategy achieved even higher directionality and the out-coupled emission was a confined beam with easy control of beam steering. Around 90% of the emitted power was confined in an angular range of 20⁰ in the detection plane. The optical properties can be optimised independently without compromising the electrical properties of devices, which gives major advantages in terms of effectiveness and versatility. Optical models were also developed to investigate the out-coupling mechanism of various trapped modes and develop OLEDs with stronger directionality.
439

Patterning of Highly Conductive Conjugated Polymers for Actuator Fabrication

Falk, Daniel January 2015 (has links)
Trilayer polypyrrole microactuators that can operate in air have previously been developed. They consist of two outer layers ofthe electroactive polymer polypyrrole (PPy) and one inner layer of a porous poly(vinylidene flouride) (PVDF) membranecontaining a liquid electrolyte. The two outer layers of PPy are each connected with gold electrodes and separated by the porousPVDF membrane. This microtool is fabricated by bottom-up microfabrication However, porous PVDF layer is not compatible with bottom upmicrofabrication and highly swollen SPE suffers from gold electrode delamination. Hence, in this MSc project/thesis a novelmethod of flexible electrode fabrication with conducting polymers was developed by soft lithography and drop-on-demandprinting. The gold electrodes were replaced by patterned vapor phase polymerized (VPP) poly(3,4-ethylenedioxythiophene) (PEDOT)electrodes due to its high electrical conductivity and versatile process ability. The replacement of the stiff gold electrodes byflexible and stretchable PEDOT allowed high volume change of the material and motions. The PEDOT electrodes werefabricated by patterning the oxidant iron tosylate using microcontact printing and drop-on-demand printing. Moreover, thePVDF membrane has been replaced by a nitrile butadiene rubber/poly(ethylene oxide) semi-interpenetrating polymer network(IPN) to increase ion conductivity and strechability and hence actuator performance.
440

Sélection et capture de biomarqueurs moléculaires et cellulaires à partir d'un fluide complexe / Physical approaches for the selection and capture of molecular and cellular biomarkers from a complex fluid

Cayron, Helene 28 October 2016 (has links)
Ce travail de thèse s'est axé autour de deux approches technologiques issues du domaine de la microfabrication pour la sélection et la capture de biomarqueurs circulants dans le sang. A l'échelle moléculaire, un module d'assemblage capillaire dirigé a été implémenté dans un automate de tamponnage moléculaire puis validé en utilisant un modèle simple, permettant l'isolement et l'étirement de biomolécules individuelles de manière entièrement contrôlée et automatisée à large échelle. Nous avons ensuite appliqué cette technologie à des biomarqueurs moléculaires d'intérêt tels que les ADN libres contenus dans du sang complet, démontrant la capacité de la technique à isoler des acides nucléiques dans un fluide complexe contenant de nombreux éléments cellulaires . A l'échelle cellulaire, une approche innovante pour la sélection et la capture de Cellules Tumorales Circulantes a été développée. Le microdispositif mis au point est fabriqué par écriture laser à 3 dimensions et permet le piégeage physique de ces cellules dans du sang complet non traité tout en les préservant pour une récupération et analyse ultérieure. Après adaptation du microdispositif pour maximiser son efficacité de capture in vitro, une première preuve de concept de capture sélective de cellules cancéreuses dans du sang complet non traité a été réalisée. U n premier prototype pour une utilisation in vivo a été mi s au point et validé in vitro sur la capture de cellules cancéreuses dans du milieu de culture. / This research project focused on two technological approaches emerging from microfabrication for the selection and capture of circulating biomarkers from blood. At the molecular scale, this work was based on the automation of a directed capillary assembly protocol. A dedicated module was implemented into an automate for molecular stampin g and validated using a simple molecular model, allowing the elongation and large-scale assembly of single biomolecules in a controlled and automatized manner. The developed technology was then used for the assembly of relevant molecular biomarkers such as cell -free DNA (cf DNA) from untreated whole blood , evidencing the capabilities of this technology to single out nucleic acids from complex fluids composed of other cellular elements. At the cellular scale, an innovative concept for Circulating Tumor Cell s (CTCs) selection and capture was developed . The developed microdevice is fabricated using 30 direct laser writing and allows for a physical capture of cell s from untreated whole blood while preserving them for further recovery and analysis. After having optimized the design in vitro to maximize the capture efficiency of the system, a selective capture of cancer cell s from untreated whole blood was achieved . A first prototype for the in vivo use of this system was also developed and validated in vitro with cancer cells spiked into culture medium.

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