Double Exchange
Mostrando 1-12 de 362 artigos, teses e dissertações.
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1. New Attempts to Synthesize Layered Double Hydroxides Intercalated with SO42-/Cs+ Using Co-Precipitation and Exchange Reactions
Layered double hydroxides (LDHs) with the compositions (Cs+/NH4+)0.111[M2+0.667Al0.333(OH)2.0 (SO4)0.222] (M2+ = Mn, Zn) and basal distance of ca. 11 Å were obtained by co-precipitating Mn/Al and Zn/Al sulfate salts with aqueous NH3, using excess of Cs2SO4. [Mn0.667Al3+0.333(OH)2]Cl0.333.nH2O and [M2+0.667Al3+0.333(OH)2](NO3)0.333.nH2O (M2+ = Mn, Zn) were a
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Synthesis, Characterization and Exchange Reactions of Layered Double Hydroxides of Copper and Aluminum, Intercalated with Sulfate
Layered double hydroxides (LDHs) of Cu:Al in the molar ratio of 2:1, intercalated with sulfate, sulfate/(Li+, Na+, K+ or NH4+), NO3- and CO32-, were synthesized by co-precipitation with increasing pH. The materials were submitted to exchange reactions using B2SO4 (B = Li+, Na+, K+, NH4+) solutions in an attempt to replace previously intercalated cations or i
J. Braz. Chem. Soc.. Publicado em: 2021-01
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3. Zn2Al Layered Double Hydroxides Intercalated with Nitrate and p-Aminobenzoate as Ultraviolet Protective Agents in Low-Density Polyethylene Nanocomposites and Natural Insulating Oils
Zn2Al-Cl and Zn2Al-NO3 layered double hydroxides (LDHs) were synthesized through the fixed pH co-precipitation method and used as precursor materials for the intercalation of p-aminobenzoate through anion exchange reactions. Since chloride in Zn2Al-Cl was only partially exchanged with p-aminobenzoate, the phases Zn2Al-NO3 and Zn2Al-N -AB (nitrate exchanged w
J. Braz. Chem. Soc.. Publicado em: 2020-05
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4. Layered Double Hydroxides with the Composition Mn/Al-SO4-A (A = Li, Na, K; Mn:Al ca. 1:1) as Cation Exchangers
Hydrated Mn/Al-SO4-A (A = Li, Na or K) layered double hydroxides with M2+:M3+ molar ratio close to 1:1 were synthesized by co-precipitation with increasing pH. All phases presented solvated alkali metals and sulfate as intercalated species. In the exchange reactions, when sulfate solutions of alkali metals were used, sodium could be partially replaced by pot
J. Braz. Chem. Soc.. Publicado em: 16/09/2019
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5. Cotidiano de cuidado de adolescentes com necessidades especiais de atenção à saúde
Resumo Objetivo Compreender o cotidiano de cuidado de adolescentes com necessidades especiais de atenção à saúde. Métodos Pesquisa qualitativa, pautada no referencial crítico-libertador Freireano, realizada no ambulatório pediátrico de um hospital de ensino, no segundo semestre de 2016. Realizou-se a análise de prontuários, entrevista semiestrutu
Acta paul. enferm.. Publicado em: 29/07/2019
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6. [Mg-Al]-LDH and [Zn-Al]-LDH as Matrices for Removal of High Loadings of Phosphate
Eutrophication is an undesirable environmental process that occurs in water bodies affected by high concentrations of phosphate. Different economic sectors are responsible for discharge effluents with extremely high phosphate content. Therefore, is important to develop technologies capable of remove phosphate from these effluents, before that reach other and
Mat. Res.. Publicado em: 15/03/2018
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7. Modeling of the temperature field generated by the deposition of weld bead on a steel butt joint by FEM techniques and thermographic images.
The aim of this work is to predict the temperature field generated by welding a steel butt joint (API 5L X80). The prediction was modeled by finite element software Abaqus where the subroutine was developed in Fortran so that heat source motion may be included. The motion was based on the Goldak's double ellipsoid. In the model material nonlinearities were i
Mat. Res.. Publicado em: 23/02/2018
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8. OXIDATION OF CYCLOHEXANOL ON PHOSPHOTUNGSTIC ACID ANION INTERCALATED LAYERED DOUBLE HYDROXIDES WITH AQUEOUS H2O2 AS OXIDANT
The layered double hydroxides (LDH) of Mg2AlNi and Mg3Al pillared by Keggin-type phosphotungstic acid anion (POM), i.e. Mg2AlNi-POM LDH and Mg3Al-POM LDH were synthesized by an ion-exchange method. The synthesized POM intercalated LDH compounds were characterized using various techniques such as FTIR, XRD, TGA and BET. The observed results show that the obta
Quím. Nova. Publicado em: 2018-01
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9. Intercalation of Molybdate Ions into Ni/Zn Layered Double Hydroxide Salts: Synthesis, Characterization, and Preliminary Catalytic Activity in Methyl Transesterification of Soybean Oil
This study reports the synthesis and characterization of a Ni/Zn layered double hydroxide salt intercalated with acetate ions and the subsequent replacement of the acetate ions with molybdate ions via an ion exchange reaction, conducted at two different pH values. Regardless of the pH employed during the synthesis, the basal spacing in the Ni/Zn layered doub
J. Braz. Chem. Soc.. Publicado em: 2017-07
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10. Estimating the Impact of an All-Electron Basis Set and Scalar Relativistic Effects on the Structure, Stability, and Reactivity of Small Copper Clusters
Basis sets of valence double and quadruple zeta qualities and the Douglas-Kroll-Hess (DKH) approximation are used to estimate the impact of an all-electron basis set and scalar relativistic effects on the structure, stability, and electronic properties of small neutral copper clusters (Cun, n ≤ 8). At the Becke three-parameter for exchange and Perdew-Wang
J. Braz. Chem. Soc.. Publicado em: 2016-01
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11. Vulnerabilidade externa e composição da posição internacional de investimentos: Brasil 2001-2010
The aim of this paper is to indicate that there was a significant change in the composition of the Brazilian International Investment Position in the period 2001-2010: international reserves became higher than the external debt and decreased the share of foreign liabilities denominated in foreign currency, getting smaller that the participation of the extern
Brazil. J. Polit. Econ.. Publicado em: 2014-09
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12. Retrograde exchange of a double J stent via a cystostomy tract
Int. braz j urol.. Publicado em: 2014-06