Zircon
Mostrando 13-24 de 81 artigos, teses e dissertações.
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13. Ab initio LSDA+U Study of Optical Properties of RVO4 (R = Eu, Ho, Lu) Compounds
A first principles investigation at the pressure 7 GPa of the optical properties of RVO4 (R= Eu, Ho, Lu) orthovanadates in the framework of the density functional theory (DFT) using the linearized-augmented plane-wave method is reported in order to predict new optical materials for continuous-wave lasers. The electronic structure of all orthovanadates is stu
Mat. Res.. Publicado em: 22/01/2018
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14. LZS/Al2O3 Glass-Ceramic Composites Sintered by Fast Firing
In this work, nanometric Al2O3 (1-5 vol.%) particles (13 nm, 100 m2/g) were added to a 19.58Li2O•11.10ZrO2•69.32SiO2 (mol%) (3.5 µm, 2.5 m2/g) parent glass-ceramic matrix to prepare composites with the purpose of studying the influence of Al2O3 on their structure, microstructure, mechanical, thermal and electrical properties when sintered by fast firing
Mat. Res.. Publicado em: 15/05/2017
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15. Effect of Heating Method on Microstructure and Mechanical Properties of Zircon Reinforced Aluminum Composites
The mechanical properties and microstructure of aluminum matrix composites containing of zircon (10, 15 and 20 wt.%) as a reinforcement particles and cobalt additive (1, 1.5 and 2 wt.%) were investigated. The aluminum matrix composites were prepared by powder metallurgy technique and sintered in both conventional and microwave furnaces at temperatures higher
Mat. Res.. Publicado em: 10/11/2016
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16. Low Temperature Sintering of Aluminum-Zircon Metal Matrix Composite Prepared by Spark Plasma Sintering
Aluminum-15 wt. % zircon metal matrix composite was fabricated using spark plasma sintering method at the temperature of 450°C and holding time of 4 min. The bending strength of 284±21 MPa and microhardness of 171±14 Vickers were determined for produced composite. XRD investigations proved that almost no decomposition of zircon particles as reinforcement
Mat. Res.. Publicado em: 12/09/2016
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17. Petrography and geochronology of the Furquim Quartzite, an eastern extension of the Itacolomi Group (Quadrilátero Ferrífero, Minas Gerais)
Abstract This paper presents the results of a petrographic and geochronological investigation of the Furquim Quartzite (FQ) to establish its stratigraphic correlation to quartzitic units of the Quadrilátero Ferrífero (QF) province. The Quartzite comprises a ca. 20km long and 1-6km wide ridge overlying discordantly the Archean to Paleoproterozoic gneissic b
Rem: Rev. Esc. Minas. Publicado em: 2015-12
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18. Iron Doped-ZrSiO4: Structural, Microstructural and Vibrational Characterization
Fex-ZrSiO4 is known for the applications in the ceramic industry such as ceramic pigment. In this article, we focus our attention to the structural, microstructural and vibrational changes of Fex-ZrSiO4 from free-mineralizer precursors, treated at different temperatures in the range of 1100-1600 °C. The refinements of X-ray diffraction patterns show that Fe
Mat. Res.. Publicado em: 03/11/2015
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19. Zircon ages delimit the provenance of a sand extrudite from the Botucatu Formation in the Paraná volcanic province, Iraí, Brazil
A determinação de idade, com microssonda iônica, de 102 cristais detríticos de zircão de um extrudito de areia, província vulcânica Paraná, estabelece limites sobre a origem das numerosas camadas de areia presentes nesta grande província de derrames basálticos. As idades U-Pb em zircão refletem quatro principais ciclos orogênicos: Mesoproterozói
An. Acad. Bras. Ciênc.. Publicado em: 25/08/2015
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20. Electron Magnetic Resonance of Diluted Solid Solutions of Gd3+ in BaTiO3
Electron magnetic resonance (EMR) spectra of gadolinium-doped barium titanate (BaTiO3) have been studied at room temperature for gadolinium concentrations between 0.20 and 2.00 mol%. The results suggest that the Gd3+ ions occupy substitutional sites, replacing the Ba2+ ion, that the electron magnetic resonance linewidth increases with increasing gadolinium c
Mat. Res.. Publicado em: 2015-04
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21. Tectonic evolution of the southern margin of the Amazonian craton in the late Mesoproterozoic based on field relationships and zircon U-Pb geochronology
Novos dados de U-Pb em zircão e relações de campo, aliados aos dados de levantamento aerogeofísico permitiu-nos sugerir que os Grupos Nova Brasilândia e Aguapeí fazem parte de uma única faixa móvel constituída por rochas metaígneas e metassedimentares, do final do Mesoproterozóico (1150 Ma -1110 Ma). Esta história geológica é muito semelhante c
An. Acad. Bras. Ciênc.. Publicado em: 2014-03
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22. Crescimento e propriedades vibracionais de cristais a base de Ãxidos / Growth and Vibrational Properties of Oxide Crystals
In this work we used different experimental techniques to study four different series of inorganic oxide crystals, namely: (i) congruent lithium isotope niobate (C7LN), (ii) rare-earth doped mixed vanadates ((Nd,Yb):YxGd1-x(VO4)); (iii) alkali metal doped and pure calcium barium niobates (CaxBa1-xNb2O6); and (iv) potassium tantalite niobate (KTa1-xNbxO3). Be
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/03/2012
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23. Geocronologia da região de Gondola-Nhamatanda (Centro de Moçambique) / não informado
The region of Gondola-Nhamatanda is located at the border between the provinces of Manica and Sofala, central part of Moçambique. It is geologically inserted in the Bárue complex and the Phanerozoic cover. The Bárue complex is composed of the Macossa and Chimoio supracrustal groups intruded by plutonic rocks of various compositions, whereas the Phanerozoi
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 17/01/2012
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24. U-Pb dating by zircon dissolution method using chemical abrasion
Este trabalho apresenta a técnica de abrasão química em zircões do padrão Temora II aplicada em datação de U-Pb por Dissolução Isotópica e Espectrometria de Massa por Ionização Térmica, método DI-ESIT. O emprego deste método tem como princípio diminuir os efeitos da perda secundária de Pb radiogênico antes da dissolução. Em primeira inst�
Anais da Academia Brasileira de Ciências. Publicado em: 2012-06