14,519 research outputs found
Letter from M.A. Fiquet to James and John Little Jr., circa 1860
No full textAn item in the Little family papers collection
Letter from M.A. Pratt to John Little Jr., circa 1880
No full textAn item in the Little family papers collection
Correspondence | Note from Mrs. M.A. Crocheson to Carl Lay, Jr., May 1912
No full textNote from Mrs. M.A. Crocheson addressed to “my dear little Carl” [Carl Lay, Jr.] accompanying the gift of a spoon, [before May 24, 1912].https://digitalcommons.jsu.edu/lib_ac_caldwell/1143/thumbnail.jp
Deep anisotropic dry etching of silicon microstructures by high-density plasmas
No full textThis thesis deals with the dry etching of deep anisotropic microstructures in monocrystalline silicon by high-density plasmas. High aspect ratio trenches are necessary in the fabrication of sensitive inertial devices such as accellerometers and gyroscopes. The etching of silicon in fluorine-based plasmas is isotropic. To obtain anisotropy the addition of sidewall passivation is necessary. This is achieved with both oxygen passivation at low temperatures and fluorocarbon passivation at room temperature. A quantitative approach was pursued to explain the etching mechanism. The etch results were analysed using the measured plasma species fluxes and the surface composition. Moreover, the transport of the plasma species in narrow anisotropic structures is a fundamental factor determining the etch rate and the profile evolution. The experimental methods such as the etching equipment, plasma diagnostics, surface analysis and sample preparation are described in chapter 2. Three etching processes were investigated: the cryogenic etching process with oxygen passivation at low temperatures, the Bosch process with fluorocarbon passivation at room temperature and the novel triple pulse process that was developed in our laboratory. The polymer deposition mechanism and the characteristic role of the ions are also explained. The cryogenic etching process is discussed in chapter 3. Fluorine radicals, oxygen radicals and ion bombardment are responsible for the three main sub-processes, that is, etching, sidewall passivation and depassivation of the trench bottom, respectively. Etching experiments with an extremely low ion-to-radical flux ratio were used to reveal the etching mechanism. Crystal orientation dependent etching leading to Si(111) crystal facets is observed in a surface kinetics controlled regime. By varying the plasma conditions it is possible to adjust the etching mechanism from fluorine-limited to ion-limited. Controlled etching is obtained because the etching is tuned from aspect ratio dependent in the fluorine-limited domain to aspect ratio independent in the ion-limited domain. The transport of radicals in high aspect ratio trenches is an important limiting factor and was investigated with special structures. The etch results are described by an analytic model that is based on the surface site balance of fluorine and oxygen radicals. The results are further explained with a Monte Carlo simulation model. The Bosch process is clarified in chapter 4. The anisotropy of the etched structures is controlled by balancing the etching and passivation pulse. However, the maximal obtainable aspect ratio is limited by convergence of the trench sidewalls due to excessive passivation. The maximal obtainable aspect ratio increases if the ion-to-radical flux ratio increases. The transport of ions is an important limiting factor in the depassivation of the bottom of the trench. Divergence of the ion beam leads to a reduction of the ion flux, so that the fluorocarbon passivation is insufficiently removed near the base of the sidewalls. The average ion angle was measured and correlated to the maximal obtainable aspect ratio. The Bosch process was improved at the depassivation side with the triple pulse process and at the passivation side with preferential sidewall deposition. The triple pulse process that is described in chapter 5 has the aim to improve the depassivation in deep trenches. The three main sub-processes are decoupled using a separate depassivation pulse directly after the etching and passivation pulses. The fluorocarbon passivation is efficiently removed with low-pressure, high-density, oxygen-based plasmas. The investigated plasma chemistries include O2, CO2 and SO2. The triple pulse process leads to better profile control with a straight trench bottom. However, the maximal obtainable aspect ratio is comparable to the Bosch process because a larger etch depth and a small lateral etch cancel out. The polymer deposition mechanism is treated in chapter 6 with the aim to understand the fluorocarbon passivation in deep trenches. The deposition on plane surfaces and on special structures was investigated to distinguish between the radical-induced and ion-enhanced components. A simple analytical model, which explains the main deposition characteristics, was developed. Preferential sidewall deposition is obtained for higher ion fluxes and higher bias voltages where sputtering plays an important role. In this case no fluorocarbon passivation has to be removed from the bottom of the trench. The trench profile was optimised in the Bosch process by tuning the bias voltage during etching and passivation independently. It resulted in perfectly anisotropic trenches but the maximal obtainable aspect ratio was still limited by a small lateral etch. The characteristic role of the ions in the etching mechanism is explained in chapter 7. Ion-induced etching of both SiC in a SF6-O2 plasma and Si in a Cl2 plasma were investigated. The impact of the ions on the profile evolution can be examined more explicitly because spontaneous chemical reactions are absent for these plasma-material systems. The etching mechanism varies from fluorine-limited to ion-limited depending on the radical-to-ion flux ratio. Microtrenches are observed for an ion-limited etching mechanism. Fluorine-limited SiC etching is aspect ratio dependent in contrast to ion-limited SiC etching, which is aspect ratio independent. The etching of high aspect ratio SiC structures is limited by the positive sidewall taper. This is presumably caused by insufficient removal of the thin fluorocarbon layer on the surface. Si etching in a Cl2 plasma is always aspect ratio independent in contrast to SiC etching because of the low reaction probability. The conclusions and recommendations of this thesis are given in chapter 8.Applied Science
Little pond
No full textThis project is a screenplay in the genre of dystopian science fiction called Little Pond. The accompanying paper presents an overview of utopian and dystopian literature. It includes an examination of Plato’s Socratic dialogue, The Republic, and challenges the accepted view it as a treatise of a utopia. This is accomplished by comparing elements from modern dystopian fiction, including Brave New World and 1984, to the political ideas in The Republic. These elements, and many other elements from dystopian fiction, inspired the story for Little Pond.Thesis (M.A.)Department of Telecommunication
Big data, little metrics : a content analysis of actionable metrics for online reporting
No full textAccess to thesis permanently restricted to Ball State community only.Access to abstract permanently restricted to Ball State community only.Thesis (M.A.)Department of Journalis
The pathology and pathogenicity of a novel Haemoproteus spp. infection in wild Little Penguins (Eudyptula minor)
No full textOne hundred and thirty four Little Penguin (Eudyptula minor) carcases found since 2004 in south west Australia were necropsied. The livers and spleens from ten of the penguins exhibited varying degrees of multifocal, randomly scattered areas of necrosis and varying numbers of parasites were associated with these areas. Hepatomegaly and splenomegaly were noted in many of these ten cases. Necrosis and parasites were also observed in the cardiac muscle of four of the cases and in the lung tissue in one of the penguins. Using PCR, the parasites were positively identified in four of the cases as Haemoproteus spp. and morphologically identical tissue stage parasites associated with histopathological changes were observed in all ten dead penguins. This is the first study to demonstrate both the in situ presence of the Haemoproteus parasite in any member of the Sphensicidae family and mortality due to its presence. We postulate the involvement of anomalous environmental conditions in a potential increase in local vectors
Aunt Helen's letters to little first communicants. By M.A. Springer.
No full text Cover title. Children's literature
Effects of Tamm-Horsfall Protein and Albumin on Calcium Oxalate Crystallization and Importance of Sialic Acids
No full text[[abstract]]Background: Tamm-Horsfall protein and human serum albumin are common urinary proteins that show uncertain inhibitory action on the crystallization of calcium oxalate monohydrate,
Materials and Methods: Batch experiments on crystal nucleation, growth, and aggregation were performed using purified Tamm-Horsfall protein and albumin before and after enzymatic removal of sialic acids from the proteins.
Results: At a concentration of 100 nM, both Talmm-Horsfall protein and albumin promoted the time of crystal nucleation by 18.4% and 8.9%, respectively, relative to the control. However, both of the proteins exerted an inhibitory effect on crystal growth, with the IC50 being 7.27 nM for Tamm-Horsfall protein and 37.5 nM for albumin. The inhibition of crystal aggregation was 81.82% by Tamm-Horsfall protein 100 nM but only 54.55% at 50 nM after enzymatic removal of the sialic acid. Instead of increasing the inhibition, the effect was changed to promotion after an increase in the concentration of Tamm-Horsfall protein to more than 500 nM for native protein and to more than 100 nM for the enzymatic digest. Albumin showed little change after enzymatic treatment and maintained a maximal inhibitory effect of 72.73% on crystal aggregation when the concentration reached to 100 nM,
Conclusion: Because the promotion of nucleation could lessen the subsequent saturation of a calcium oxalate solution, it is concluded that Tamm-Horsfall protein and albumin show an overall effect of inhibition on crystallization in vitro. The inhibitory effect of Tamm-Horsfall protein is partly related to sialic acid.[[fileno]]2050112010016[[department]]生科
Determining management methods used to evaluate automation systems
No full textThe purpose of this paper is to determine the methods which are presently being used to evaluate automation systems in industry. With the increased volume of sales and higher production costs, new methods are continually being explored to increase the productivity of each industry. One method employed by industry is the increased use of automation systems. A sound and accurate means of determining when and to what extent to automate is very desirable. It will give the managers an economic justification for proposals of such systems. Eventhough there has been an extensive amount of writing and research on the justification process, little research has been done on the actual methods which industries employ. From the results of the research it is felt that managers will be better able to choose the particular method which they wish to employ.Thesis (M.A.
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