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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.
221

Investigation into a low cost stereolithography system for rapid prototyping

Pienaar, M. G. 20 August 2015 (has links)
M.Ing. / Please refer to full text to view abstract
222

Microfabrication of Plasmonic Device: PPBG BIosensor in Cytop, Reflection Itensity Modulator and Atomically Flat Nanohole Array

Hassan, Sa'ad January 2015 (has links)
This thesis details the fabrication of three different plasmon-polariton based devices: a plasmon-polariton Bragg grating (PPBG) biosensor, an intensity modulator incorporating grating couplers, and optically separated electrical contact, and finally an array of nanoholes in an ultrasmooth Au film. The biosensor involves a 35 nm Au stripe, lithographically stepped in width to produce a Bragg reflector. The waveguide is embedded in symmetric, Cytop claddings 8 µm thick. Channels are etched into the top cladding, exposing the waveguides and allowing for the integration of fluidics. The modulator involves a 20 nm Au pad, overlaid with 80 nm Au diffraction gratings, supported by an ultrathin (~3 nm) SiO2 insulator, on a p-doped Silicon wafer backed by an Al Ohmic contact. Electrical contact pads are separated from the waveguide by a thick dielectric (700 nm PMMA), and 2.5 µm vias in-filled with Au allow for electrical connection between the contact pads and waveguides. The nanohole array is machined by focused ion beam into an ultrasmooth Au film revealed by template stripping. The Au film is stacked on a thick film of Cytop between ~5 µm thick.
223

Desenvolvimento e avaliação de dispositivos para liberação de fármacos usando microfabricação / Development and evaluation of devices for drug release using microfabrication

Carvalho, Claudio Roberto Cutrim, 1971 27 August 2018 (has links)
Orientador: Cecília Amélia de Carvalho Zavaglia / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T18:19:16Z (GMT). No. of bitstreams: 1 Carvalho_ClaudioRobertoCutrim_D.pdf: 4942527 bytes, checksum: c95fc9ea9d486c5f468d6780906cc6c5 (MD5) Previous issue date: 2015 / Resumo: Este trabalho tem como objetivo a fabricação de 3 classes de dispositivos implantáveis para liberação de drogas, produção intra-corpórea de proteínas recombinantes e regeneração de tecidos. Os dispositivos fabricados, a saber são: biorreator implantável para produção de proteínas recombinantes intra-corpóreo, um protótipo construído de titânio (usinado) e outro bioaborvivel construído com poli(ácido láctico-co-glicólico) 50/50% através da litografia macia; sistema anti-infecção composto de termoresistores para produção de calor com o objetivo de inibir o crescimento bacteriano associado com microreservatórios para liberação de antibióticos bactericidas; neurotubos e dispositivos de liberação de drogas implantáveis, o primeiro para fomentar a regeneração de nervos periféricos, e o último com objetivo de liberar drogas, os materiais usados na fabricação destes dispositivos foram o Poli-Dimetil Siloxano(PDMS) e o PSG(Poli-Sebacato de Glicerol).Os 4 dispositivos tem como processo de fabricação principal a tecnologia de litografia macia. Em relação aos resultados, o biorreator implantável produziu as proteínas recombinantes BMP-2 (induzem formação óssea) verificadas através de testes in vitro de detecção das proteínas recombinantes; os resultados do desenvolvimento do neurotubo e dispositivos implantáveis, resultaram em testes de liberação de antibióticos in vivo com sucesso em ratos da raça Winstar; o sistema anti-infecção apresentou resultados animadores quanto a função de seus componentes principais: o termoresistor através da monitoração da produção de corrente, e os reservatórios liberadores de antibióticos, através dos testes in vitro com culturas bacterianas. Palavras-chave: Litografia macia, sistema anti infecção, biorreator, regeneração nervosa / Abstract: The main goal of this work is the manufacturing of four classes of implantable devices for delivering drugs, recombinant proteins for intra-body production and tissue regeneration. The 3 devices are: implantable bioreactor for the production of recombinant proteins intra- corporeal, one prototype built in titanium(machined) and the other one bioabsorbable, constructed with poly (lactic-co-glycolic acid) 50/50% through the soft lithography technology; System anti-infection compounds of resistance thermometers for heat production with the goal inhibiting bacterial growth with the associated microreservoirs to deliver bactericidal antibiotics; Neurotubes and implantable drugs release devices, the first dedicated for peripheral nerve regeneration, and second one for release drugs, the materials used in the manufacture of these devices was Poly-dimethyl siloxane (PDMS) and PSG (poly-glycerol sebacate). The 4 devices has main manufacturing process the soft lithography technology. About results, the implantable bioreactor produced recombinant proteins BMP-2 (induce bone formation) verified through testing in-vitro for detection of the recombinant protein; The development of neurotube and implantable devices results in successfully liberation tests of antibiotics in-vivo in rats Winstars. The anti-infection system showed encouraging results as the function of its main components: the termoresistor through the tests of current production and monitoration, and the releasing reservoirs of antibiotics, through the testes in vitro with bacterial cultures. Key-words: Soft lithography, nerve regeneration, bioreactor, system anti infection / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica
224

A process overview of faux-to-gravure and paper films for photolithography

Mazzupappa, Ross Joseph 01 May 2015 (has links)
Tradition begins with innovation. The rich and complicated history of Printmaking is shaped by invention and discovery. I see this advancement for the sole purpose to distribute knowledge and ideas to every person regardless of prosperity and status. At its core intention is the need to make art and knowledge accessible. The procedural research I have been exploring along side my artist research was designed to do just as invention in printmaking has done before. I have applied my knowledge and availability of modern technology with traditional ways print artists create. These new processes are geared to make photomechanical practices in lithography and intaglio cheaper and more accessible to artists and students with limited resources. I have also included a statement about the artwork that has been able to be developed because of this research to provide context for my artistic practice.
225

Pokročilé techniky vytváření mikro a nanosystémů pro senzoriku / Advanced techniques of micro- and nanosystems fabrication for sensors

Márik, Marian January 2013 (has links)
The use of micro- and nanotechnologies is necessary in the development of advanced sensor systems. In this thesis few selected technologies were studied and tested on fabrication of creating two different systems for bioelectrical and electrochemical applications. For biolelectrical applications a chip with a pair of gold nanoelectrodes was designed and implemented. For electrochemical analysis a novel two electrode system was designed and realized, which should contribute by greater sensitivity and accuracy in amperometric detection compared with three-electrode systems in voltammetric analysis. The fabricated systems were tested and the results were discussed.
226

Optical Simulation and Colloidal Lithography Fabrication of Aluminum Metasurfaces

January 2019 (has links)
abstract: Solar energy has become one of the most popular renewable energy in human’s life because of its abundance and environment friendliness. To achieve high solar energy conversion efficiency, it usually requires surfaces to absorb selectivity within one spectral range of interest and reflect strongly over the rest of the spectrum. An economic method is always desired to fabricate spectrally selective surfaces with improved energy conversion efficiency. Colloidal lithography is a recently emerged way of nanofabrication, which has advantages of low-cost and easy operation. In this thesis, aluminum metasurface structures are proposed based on colloidal lithography method. High Frequency Structure Simulator is used to numerically study optical properties and design the aluminum metasurfaces with selective absorption. Simulation results show that proposed aluminum metasurface structure on aluminum oxide thin film and aluminum substrate has a major reflectance dip, whose wavelength is tunable within the near-infrared and visible spectrum with metasurface size. As the metasurface is opaque due to aluminum film, it indicates strong wavelength-selective optical absorption, which is due to the magnetic resonance between the top metasurface and bottom Al film within the aluminum oxide layer. The proposed sample is fabricated based on colloidal lithography method. Monolayer polystyrene particles of 500 nm are successfully prepared and transferred onto silicon substrate. Scanning electron microscope is used to check the surface topography. Aluminum thin film with 20-nm or 50-nm thickness is then deposited on the sample. After monolayer particles are removed, optical properties of samples are measured by micro-scale optical reflectance and transmittance microscope. Measured and simulated reflectance of these samples do not have frequency selective properties and is not sensitive to defects. The next step is to fabricate the Al metasurface on Al_2 O_3 and Al films to experimentally demonstrate the selective absorption predicted from the numerical simulation. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2019
227

3D Printed Micro-Optics for Biophotonics

Bertoncini, Andrea 07 1900 (has links)
3D printing, also known as ”additive manufacturing”, indicates a set of fabrication techniques that build objects by adding material, typically layer by layer. The main advantages of 3D printing are unlimited shapes and geometry, fast prototyping, and cost-effective small scale production. Two-photon lithography (TPL) is a laserbased 3D printing technique with submicron resolution, that can be used to create miniaturized structures. One of the most compelling applications of TPL is the 3D printing of miniaturized optical elements with unprecedented complexity, small-scale and precision. This could be potentially beneficial in biophotonics, a multidisciplinary research field in which light-based techniques are used to study biological processes. My research has been aimed at demonstrating novel applications of 3D printing based on TPL to different biophotonic applications. In particular, here we show 3D printed micro-optical structures that enhance and/or enable novel functions in advanced biophotonics methods as two-photon microendoscopy, optical trapping and Stimulated Raman Scattering microscopy. Remarkably, the micro-optical structures presented in this thesis enable the implementation of advanced techniques in existing or simpler microscopy setups with little to no modification to the original setup. This possibility is essentially allowed by the unique miniaturization and in-situ 3D printing capabilities offered by TPL.
228

A Process for Hybrid Superconducting and Graphene Devices

Cochran, Zachary 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / As the search for ever-higher-speed, greater-density, and lower-power technologies accelerates, so does the quest for devices and methodologies to fulfill the increasingly-difficult requirements for these technologies. A possible means by which this may be accomplished is to utilize superconducting devices and graphene nanoribbon nanotechnologies. This is because superconductors are ultra-low-power devices capable of generating extremely high frequency (EHF) signals, and graphene nanoribbons are nanoscale devices capable of extremely high-speed and low-power signal amplification due to their high-mobility/low-resistance channels and geometry-dependent bandgap structure. While such a hybrid co-integrated system seems possible, no process by which this may be accomplished has yet been proposed. In this thesis, the system limitations are explored in-depth, and several possible means by which superconducting and graphene nanotechnological systems may be united are proposed, with the focus being placed on the simplest method by which the technologies may be hybridized and integrated together, while maintaining control over the intended system behavior. This is accomplished in three parts. First, via circuit-level simulation, a semi-optimized, low-power (~0.21 mW/stage) graphene-based amplifier is developed using ideal and simplified transmission line properties. This system is theoretically capable of 159-269 GHz bandwidth with a Stern stability K >> 1 and low noise figure 2.97 <= F <= 4.33 dB for all appropriate frequencies at temperatures between 77 and 90 K. Second, an investigation of the behavior of several types of possible interconnect methodologies is performed, utilizing hybrid substrates and material interfaces/junctions, demonstrating that an Ohmic-contact superconducting-normal transmission line is optimal for a hybrid system with self-reflections at less than -25 dB over an operating range of 300 GHz. Finally, a unified layout and lithography construction process is proposed by which such a hybrid system could be developed in a monolithic physical system on a hybrid substrate while maintaining material and layout integrity under varying process temperatures.
229

Design and fabrication of photonic devices using phase change materials

Guo, Pengfei January 2018 (has links)
No description available.
230

A Novel Process for Continuous Thermal Embossing of Large-Area Nanopatterns onto Polymer Films

Fagan, Matthew D 01 January 2008 (has links) (PDF)
As imprint lithography becomes commonplace in industrial manufacturing, the need for fast, reliable modifications to the process are of great importance. In particular, the Roll-to-Roll Nanoimprint Lithography (R2RNIL) method has been proven to yield large areas of continuous, robust patterns in the micro- and nanometer range. A thermal embossing R2RNIL system has been developed that is capable of providing a mold heating rate of 100ºC/s with sufficient temperature control to produce large-area patterns continuously at a rate in excess of four feet per minute. This process uses a novel looped-conveyor mold, allowing longer continuous patterns to be produced with superior temperature control than other methods of R2RNIL. Various patterns in the micro- and nanometer domains were replicated using this process.

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