Departamento de Física
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/785
Navegar
2 resultados
Resultados da Pesquisa
Artigo de evento 3 Citação(ões) na Scopus Radiation effect mechanisms in electronic devices(2013-12-01) Marcilei Aparecida Guazzelli; Roberto Santos; LEITE, F.; CUNHA, F.; CIRNE, K. H.; MEDINA, N. H.; ADDED, N.; AGUIAR, V. A. P.© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.In this work, P- and N-MOSFETs (Metal Oxide Semiconductor Field Effect Transistor) were submitted to X-ray and ion beams. CD 4007, a commercial off-the-shelf integrated circuit composed of six transistors, three P-type and three N-type, in a single package, was used. The integrated circuits were exposed to 60 MeV 35Cl ion beams using the São Paulo 8UD Pelletron Accelerator and 10 keV X-ray radiation, using a Shimadzu XRD-7000 X-ray diffractometer. The total dose effects due to ionizing radiation in MOSFET were analyzed. The results indicate Vth depends on the absorbed dose and dose rate. The deviation of Vth is higher for P-MOS, while the change in slope is higher for N-MOS. TID (Total Ionizing Dose) caused by heavy ion does not seem to affect mobility. After heat treatment, the device establishes a different equilibrium state compared to that achieved at room temperature. The heat treatment worsens the P-type characteristics and improves the N-type.Artigo de evento 1 Citação(ões) na Scopus Titanium extraction from waste NORM(2013-12-01) PEREIRA, B. R.; Marcilei Aparecida Guazzelli; FONTANA, G.; Roberto Santos; RIZZUTTO, M. A.; MEDINA, N. H.© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.The constantly growing of global agricultural production depends on the development of a whole production to be lasting and sustainable. The phosphoric acid production is directly related to the production of fertilizers, but its process of obtaining requires numerous steps and generates a lot of waste. There are several elements in some of these wastes that are very valuable and important for economy and for technological development. An example is a residue derived from a step of physical handling of the phosphate rock, containing about 30% of titanium in its composition. Titanium can be used in various applications, such as a component in high-tech metallic alloys, or, in the form of titanium dioxide, which is the form that presents the greatest value in industry. This study focus at the concentration of titanium oxide present in a residue from the phosphoric acid production, by attacking the material chemically and doing its characterization by analytical methods. This would contribute to the national titanium concentrated production increased and enhance the economic yield of the phosphoric acid production process, by transforming an unused waste in a high value product. The methodology for the concentration of titanium oxide was based in industrial extraction of titanium ores and consists of solubilizing the impurities present in the sample by means of chemical attack. It has been determined experimentally that at temperatures around 70°C, hydrochloric acid provides a better solubilization of impurities, without extracting titanium, and it is possible to obtain a residual solid phase with about 58.5% of titanium on it. The results were determined by using the Energy Dispersive X-Ray Fluorescence (EDXRF) technique. As the original sample is a Normal Occurring Radioactive Material (NORM), an analysis of Gamma Ray Spectroscopy and EDXRF were realized to determine how the radionuclides form the U and Th series were affected by the chemical treatment.