9,293 research outputs found
Postcard from M.A. Perkins, to Mabel Rozelle, April 11, 1909
No full textPostcard from M.A. Perkins, to Mabel Miles (née Rozelle), stating that she enjoyed her letter and was glad to hear Mabel's mother, Edith Rozelle, and the baby are doing well.The Rozelle collection, ranging from the late 1860's to the early 2000's contains correspondence, photographs, official documents, newspaper clippings, and genealogy information pertaining to the family of Bazil Tillson Rozelle. Letters reflect current and family affairs; and agricultural conditions of Compton in that era. Photographs include family vacations in Catalina Island circa 1890s; Compton, Paramount, and Lynwood areas circa 1890s; World War II boat christening from Terminal Island CA circa 1940s; and mink farming in southern California circa 1940s-1950s
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
Persons Known - Miles, Gov.
No full textOld timers in New Mexico met with Governor John E. Miles in Santa Fe, New Mexico, on Nov. 20, 1939 to organize the New Mexico Trail Drivers Association. Among those attending were (left to right) First Row: A.C. Heard, Frank M. Jones, former Governor M.A. Otero, Governor Miles, Montague Stevens, Second Row: George L. Ulrick, Hal L. Kerr, Carl Livingston, R.P. Pankey, Col. Jack Potter. Photography by Wyatt Davis, Canyon Road, Santa Fe
Letter from Miles Alexander Rozelle, to Bazil Tillson Rozelle, May 30, 1910
No full textLetter from most likely M.A. [Miles Alexander] Rozelle to his brother, Bazil Tillson Rozelle, regarding the birth of his son; the health of Sadie and the baby; and his children greeting him on the way home. He also reports about the Rozelle Ranch and how it is doing, including what the Chicano farm workers are working on, and how Bazil's sons are doing taking care of the ranch in Bazil's absence. He also mentions Edith's health and her view of the estate of affairs on the ranch.Letter contains racist language.The Rozelle collection, ranging from the late 1860's to the early 2000's contains correspondence, photographs, official documents, newspaper clippings, and genealogy information pertaining to the family of Bazil Tillson Rozelle. Letters reflect current and family affairs; and agricultural conditions of Compton in that era. Photographs include family vacations in Catalina Island circa 1890s; Compton, Paramount, and Lynwood areas circa 1890s; World War II boat christening from Terminal Island CA circa 1940s; and mink farming in southern California circa 1940s-1950s
Exterior view of an adobe on Rancho Las Flores, built by M.A. Foster, located 6 miles north of Oceanside, east of main road, 1870-1880
No full textPhotograph of the exterior view of an adobe on Rancho Las Flores, built by M.A. Foster, located 6 miles north of Oceanside, east of main road, 1870-1880. The building is two-stories and features a covered walkway on both floors. Large trees flank the house. A picket fence forms a perimeter around the house. Picture file card reads: "Near this, San Luis Rey Mission was established -- an asistencia for the ranchero and Indians." Compares to CHS-8602
Context dependent memory and stress: a preliminary investigation using multi-task induced stress
No full textValidation of E-Science Experiments using a Provenance-based Approach
No full textE-science experiments typically involve many distributed services maintained by different organisations. As part of the scientific process, it is important for scientists to be able to verify the correctness of their own experiments, or to review the correctness of their peers’ work. There is no existing framework for validating such experiments. Users therefore have to rely on error checking performed by the services, or adopt other ad hoc methods. This paper introduces a platform independent framework for validating workflow executions. The validation relies on reasoning over the documented provenance of experiment results and semantic descriptions of services advertised in a registry. This validation process ensures experiments are performed correctly, and thus results generated are meaningful. The framework is tested in a bioinformatics application that performs protein compressibility analysis
Assessment of Models for Near Wall Behavior and Swirling Flows in Nuclear Reactor Sub-system Simulations
No full textAccurate simulation of turbulence remains one of the most challenging problems in nuclear reactor analysis and design. Due to limitations in computing resources, Reynolds averaged Navier Stokes models (RANS) continue to play an important role in reactor simulations. The Consortium for advanced simulations of light water reactors (CASL) is a Department of Energy technology hub that is investing in research and developmentof a state-of-the-art computational fluid dynamics capabilityto meet the challenges of turbulent simulation of nuclear reactors. In this presentation, we assess several RANS eddy viscosity models appropriate for single-phase incompressible turbulent flows. Specifically, we compare the single equation Splalart-Allmaras to several variations of the model. The assessment takes into consideration elements of full system reactor cores such as complex geometries, heterogeneous meshes, swirling flow, near wall flow behavior, heat transfer and robustness issues. The goal of this strategically oriented assessment is to provide an accurate and robust turbulent simulation capability for the CASL community. Metrics of performance will be constructed by comparing different models on a strategically chosen set of problems that represent reactor core sub-systems
O zarubežnoj dejatel'nosti professora M.A. Kumaxova
No full textOn professor M.A. Kumakhov's work and research abroad (in Russian)
Professor Mukhadin A. Kumakhov and the author collaborated in the area of Northwest Caucasian languages under a period from 1991 to 2008. The fruitful collaboration at Lund and Malmö universities resulted in three joint monographs and a number of articles, which is outlined in the article. Mukhadin A. Kumakhov became Honorary Doctor of the Philosophical Faculty of Lund University in 1998
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