The fabrication characteristic of focused ion beam (FIB) for Pyrex glass was investigated. FIB has several advantages such as high sensitivity, high material removal rates, low forward scattering, and direct fabrication in selective area without any etching mask, etc. In this study, FIB etched Pyrex glass was used for fast fabrication of 3-D submicron structures. A high-aspect-ratio (HRA) glass structure of 5 (1.97µm depth/0.39µm width) was fabricated. The experimental results in terms of limiting beam size, ion dose¡]ion/cm2¡^, beam current, etc was discussed. Xenon difluoride (XeF2) was applied to enhance the FIB process. Its influence on glass fabrication is studied and characterized.

Focused Ion Beam (FIB) has several advantages such as high sensitivity, high material removal rates, low forward scattering and directing fabrication. Without any etched mask, processing time can be reduced. Pyrex glass etched by FIB is used for fast fabrication of 3-D submicron structure mold. In this study, glass is used as substrate. The UV-cured resin that spin-coated onto a mold has 3-D structure patterns. 3-D structure patterns are transferred on the plate to investigate the effects of parameters of UV cured, pressure and exposure time on the occurrence of defects. The relationship of these processing parameters for the imprinting process is also realized. Besides, the material property of UV-cured resin is investigated. UV-Cured resin is investigated by thermogravimetric Analysis (TGA) to measure the degradation temperature (Td). The hardness and modulus of UV-Cured resin was measured by nanoindentation to realize deformed ability of material for the imprinting process. Moreover, the contact angle of Pyrex glass is measured to investigate its surface quality for the imprint process.

Precipitation with a Compressed Fluid Antisolvent (PCA) and Rapid Expansion from Supercritical Solution (RESS) are two processes based on supercritical fluids that are capable of producing submicron particles. Novel variations of these basic processes have been examined to produce stable particles of various pharmaceutical compounds. PCA is an antisolvent precipitation technique where an organic solution of drug + polymer in solvent is atomized (sprayed) into supercritical (SC) CO₂. Upon liquid mixing, the solute materials precipitate to form microparticles. A Vapor-over-Liquid technique has been used to produce larger, uniform particle sizes of biodegradable polymers. By suspending a protein in the solvent phase, the protein can be encapsulated/coated by the precipitating polymer. RESS is a process by which a homogeneous solution at supercritical conditions is sprayed through an expansion nozzle to atmospheric conditions. The resultant change in phase leads to the precipitation of the solute materials. The production of extremely small particles (<50 nm) have been predicted but rarely demonstrated. Typically, particle growth occurs to form larger (~1 μm) particles. A novel adaptation was developed, dubbed RESAS (Rapid Expansion from Supercritical to Aqueous Solution), wherein the expansion is conducted within an aqueous environment. The aqueous phase can contain surfactant or lipid stabilizers to capture and preserve submicron particles of water-insoluble drug actives in the form of a suspension. / text

No description available.

This research investigated effect of submicron glass fiber modification on mechanical performance of short carbon fiber reinforced vinyl ester resin. Firstly, the mixture of resin and glass fiber was made by mixing submicron fiber into resin in a homogenizer at the speed of 5000 rpm in 30 minutes. Then, this modified resin was reinforced by short carbon fiber at the length of 1 mm, 3mm and 25 mm. The modifying effects were accessed by evaluating mechanical properties such as: bending, tensile, impact test as well as dynamic mechanical analysis. To explain some manners of material caused by adding glass fiber into resin, some techniques were also used (IFSS, SEM, laser microscope scanner, ultrasonic S-scan, X-ray ...). / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

Sub-micron patterning is fundamental to the fabrication of numerous devices Traditional commercial manufacturing methods either lack the resolution needed to attain the appropriate size or are prohibitively expensive due to low throughput or the necessity of expensive equipment. Imprint lithography is a rapid, inexpensive alternative to making sub-micron features that can be tailored to work with a variety of materials. Imprint lithography, while traditionally used with pure polymers has been tailored to be used with nanoparticle-polymer hybrid films. This work has achieved high-fidelity pattern transfer onto polymer-nanoparticle hybrid films with feature sizes as small as 250 nm. The polymer-nanoparticle hybrid was fabricated by creating a liquid suspension of functionalized ZnO nanoparticles and poly(methyl methacrylate) (PMMA) in a solvent. The ZnO particles were functionalized by adding nonanoic acid in order to facilitate the dispersion of the particles in a non-polar solvent. This suspension was spread onto substrate, imprinted with a patterned stamp, allowed to dry, and was demolded. The final result was features ranging from 250 nm to 1 μm in size with good fidelity as determined by the accuracy of the feature replication and the surface roughness of the overall sample. The effect of the ZnO content as well as the method of combining the suspension components on the feature fidelity was studied. In general, it was found that feature fidelity is acceptable up to a dry-film composition of 15 vol% ZnO and that feature sizes above 500 nm were more tolerant of higher solids loading. The same imprint lithography method was also used to pattern a polymer-derived SiOC glass. The SiOC was shown to be have interesting shrinkage properties where the feature-level linear shrinkage was up to 5% more than that of the bulk. The features were shown to be stable during pyrolysis up to 1000°C and stable at operating temperatures up to 1000°C. A constant number Monte Carlo simulation was used to describe the suspension behavior to confirm the empirical results from the physical experiments. The effects of Van der Waals forces, steric stabilization, depletion flocculation, as well as the physical impediment of entangled polymer chains were considered. A similar agglomeration behavior was shown in the simulations compared to the physical experiments. This thesis shows that polymer-nanoparticle hybrid films are a compatible material for imprint lithography using appropriate suspension parameters. This is very important for a variety of applications and devices. Using imprint lithography to make these devices makes them cheaper and more accessible to the commercial market and can make a large number of theoretical devices a reality. / Ph. D. / Sub-micron patterning is an integral part of making many modern technologies such as memory storage devices or integrated circuits. As this technology becomes smaller and smaller, the limiting factor for making these devices has become the ability to manufacture effectively at the appropriate scale. Traditional commercial manufacturing methods lack the resolution needed to attain small enough features. Manufacturing methods that can make small enough features are often either extremely expensive or offer incomplete control of the feature morphology. Imprint lithography is a high-throughput, inexpensive alternative to making sub-micron features that can be tailored to work with a variety of materials. Imprint lithography is simple process in which a patterned stamp is pressed into a softened film of material in order to transfer the pattern of the stamp onto that material. Traditionally, imprint lithography works best with polymers and researchers have struggled to pattern nanoparticle-based materials. This work has achieved high-fidelity pattern transfer onto polymer-nanoparticle hybrid films with feature sizes on the same order as the polymer films found reported in literature. The polymer-nanoparticle hybrid was realized by creating a liquid suspension of functionalized ZnO nanoparticles and poly(methyl methacrylate) (PMMA) in a solvent. The ZnO particles were functionalized by adding nonanoic acid, allowing the normally polar particles to disperse in the non-polar solvent needed to dissolve the PMMA. This suspension was spread onto a glass substrate, imprinted with a patterned stamp, allowed to dry, and was demolded. The final result was the successful transfer of features ranging from 250 nm to 1 μm in size with good fidelity. The effect of the ZnO content as well as the method of combining the suspension components on the feature fidelity was studied. To help prove the broad applicability of this imprint method, it was adapted for use with polymer-derived ceramics. Additionally, a computer simulation was developed to help understand the behavior of the nanoparticle-polymer suspension during the imprint process.

No description available.

State-of-the art electronic systems include ever more features and gather mixed-signal subsystems, possibly from different physical domains. At the same time, cost and development time are reduced; stressing the need for an efficient design flow for fast and reliable design. The present thesis contributes to the construction of an improved design flow supported by mixed-signal hardware description languages (HDL-AMS). In a hierarchical view, the electronic systems are recursively divided into subsystems, down to basic cells and transistor level. The typical design flow results of a top-down synthesis, from the system specifications to the physical realizations, and of a bottom-up validation, from the test of the basic cells up to the test of the system. To improve the link between the technological level and the basic cells, we develop a measurement-based analog ID card which aims to optimize the analog performance and the reliability at high temperature by enabling the choice of optimal process (bulk vs. partially-depleted silicon-on-insulator (SOI) vs. fully-depleted SOI), optimal devices (e.g. multi-threshold voltages process) and optimal bias (weak vs. moderate vs. strong inversion). In the present thesis, we deal with the following analog performance parameters: gain, gain-bandwidth product, MOSFET mismatch in weak inversion and harmonic distortion of MOSFETs in triode regime. We show that SOI transistors are still advantageous over bulk in deep-submicron CMOS technologies and that short-channel SOI transistors can safely be used for mixed-signal operation up to 250°C. The analog ID card can be included in the design flow supported by HDL-AMS. Behavioral models for the basic cells are developed using such languages and further assembled into a ÄÓ modulator with continuous-time integrators as it is a good candidate for low-power consumption and operation at high temperature. The related design issues are assessed using the behavioral models and a design optimization method is presented for a key building block, an active RC integrator with passive resistors.

L’objectif de la thèse est l’étude et le développement de médias fibreux avec des fibres ultrafines à travers l’utilisation de la technologie nano-meltblown ainsi que de l’utilisation de fibres bicomposantes îles-en-mer. Cette approche implique un double travail, à la fois sur l’obtention de fibres ultrafines et sur l’homogénéité des médias fibreux. En effet, pour chaque technologie, l’élaboration d’un média fibreux induit une certaine hétérogénéité. L’origine de cette hétérogénéité est multiple : distribution des diamètres des filaments, variation locale de l’épaisseur, de compacité ou de la masse de fibres. Ce qui nous a conduit à mener, en parallèle des travaux d’élaboration de médias, une étude et une modélisation des performances de filtration afin de mieux comprendre l’impact des fibres ultrafines et de l’hétérogénéité des médias fibreux en filtration de l’air. La majorité des modèles de filtration (perméabilité et efficacité) considèrent, en effet, un média fibreux idéal avec des fibres monodisperses et une répartition de matière homogène au sein du média fibreux. Or, en réalité, ces conditions sont rarement réunies, ainsi comprendre l’influence des différentes hétérogénéités sur les performances de filtration peut s’avérer un enjeu important pour améliorer les performances des médias filtrants. La modélisation de cette hétérogénéité se fonde sur la correction des modèles d’efficacité de la littérature à partir des données expérimentales / The goal of the thesis is the study and development of fibrous media with ultrafine fibers through the use of nano-meltblown technology as well as the use of bicomponent islands-in-sea fibers. This approach involves dual work, both on obtaining ultrafine fibers and on the homogeneity of fibrous media. Indeed, for each technology, the elaboration of a fibrous media induces heterogeneities. The origin of this heterogeneity is multiple: distribution of filament diameters, local variation in thickness, packing density or basis weight. This led us to carry out a study and a modeling of the filtration performance in order to better understand the impact of ultrafine fibers and the heterogeneity of fibrous media in air filtration. Most of filtration models (permeability and efficiency) consider an ideal fibrous media with monodisperse fibers and a homogeneous distribution of matter within the fibrous media. In reality, these conditions are rarely met, so understanding the influence of different heterogeneities on filtration performance can be an important issue to improve the performance of filtering media. The modeling of this heterogeneity is based on the correction of the models of effectiveness of the literature from the experimental data

Made available in DSpace on 2014-12-17T15:01:32Z (GMT). No. of bitstreams: 1 AndreACP_DISSERT.pdf: 6190808 bytes, checksum: 21a983a9627b562fbe33e41da8ebdfd8 (MD5) Previous issue date: 2013-08-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Polymer particles in the nanometer range are of fundamental interest today, especially when used as carrier systems in the controlled release of drugs, cosmetics and nutraceuticals, as well as in coating materials with magnetic properties. The main objective of the present study concerns the production of submicron particles of poly (methyl methacrylate) (PMMA) by crystallization of a polymer solution by thermally controlled cooling. In this work, PMMA solutions in ethanol and 1-propanol were prepared at different concentrations (1% to 5% by weight) and crystallized at different cooling rates (0.2 to 0.8 ? C / min) controlled linearly. Analysis of particle size distribution (DLS / CILAS) and scanning electron microscopy (SEM) were performed in order to evaluate the morphological characteristics of the produced particles. The results demonstrated that it is possible to obtain submicron polymer perfectly spherical particles using the technique discussed in this study. It was also observed that, depending on the cooling rate and the concentration of the polymer solution, it is possible to achieve high yield in the formation of submicron particles. In addition, preliminary tests were performed in order to verify the ability of this technique to form particulated carrier material with magnetic properties. The results showed that the developed technique can be an interesting alternative to obtain polymer particles with magnetic properties / Part?culas polim?ricas formadas em escala nanom?trica s?o de fundamental interesse atualmente, principalmente quando utilizadas como sistemas carreadores na libera??o controlada de f?rmacos, cosm?ticos e nutrac?uticos, al?m do interesse pr?tico no recobrimento de materiais com propriedades magn?ticas. O principal objetivo do presente estudo diz respeito ? produ??o de part?culas submicrom?tricas de poli(metacrilato de metila) (PMMA) atrav?s da t?cnica de cristaliza??o de uma solu??o polim?rica por resfriamento controlado termicamente, segundo um perfil de taxa linear de resfriamento. Neste trabalho, solu??es de PMMA em etanol e 1-propanol foram preparadas em diferentes concentra??es (1% a 5% em massa) e cristalizadas em diferentes taxas de resfriamento (0,2 a 0,8 ?C/min) controladas linearmente. An?lises de distribui??o de part?culas (DLS/CILAS) e microscopia eletr?nica de varredura (MEV) foram realizadas com o intuito de avaliar as caracter?sticas morfol?gicas das part?culas formadas. Os resultados demonstraram que ? poss?vel obter part?culas polim?ricas submicrom?tricas com morfologia perfeitamente esf?rica utilizando a t?cnica abordada no presente estudo. Observou-se tamb?m que, a depender da taxa de resfriamento e da concentra??o da solu??o polim?rica, ? poss?vel ter alto rendimento na forma??o de part?culas submicrom?tricas. Adicionalmente, foram realizados testes preliminares com o prop?sito de verificar a capacidade desta t?cnica em formar part?culas carreadoras de materiais com propriedades magn?ticas. Os resultados permitiram concluir que a t?cnica estudada pode ser uma alternativa interessante na obten??o de part?culas polim?ricas com propriedades magn?ticas