Vibrational Spectra
Mostrando 1-12 de 162 artigos, teses e dissertações.
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1. DESENVOLVIMENTO DE ACESSÓRIO PORTÁTIL DE CONTROLE DE TEMPERATURA PARA MEDIDAS ESPECTROSCÓPICAS
Temperature is a natural phenomenon that may modify the structure of chemical compounds and hence their properties. We aimed to develop a simple portable system based on the Peltier principle for spectral characterization of compounds with temperature-dependent structure. The device was constructed and adapted to three pieces of equipment: X-ray diffractomet
Química Nova. Publicado em: 2022
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2. Study of structural, optical, and morphological characteristics of manganese titanate (MnTiO3) obtained by combustion reaction using microwave energy
Abstract MnTiO3 is a semiconductor that has relevant dielectric and optical properties. For the synthesis of manganese titanate (MnTiO3) powders, the combustion method via microwave and subsequent calcination at 500, 700, and 900 °C were used. The structural, morphological, and optical properties of the samples were investigated. X-ray diffraction analyzes
Cerâmica. Publicado em: 2021-03
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3. Intercalation of Apocarotenoids from Annatto (Bixa orellana L.) into Layered Double Hydroxides
Synthetic conditions were evaluated to intercalate norbixin into layered double hydroxides (LDH). Norbixin was isolated from a hydrosoluble commercial annatto extract. LDH samples comprising M2+/Al3+ (M = Mg, Zn) were synthesized by coprecipitation and characterized by X-ray diffraction, thermal analysis coupled to mass spectrometry, vibrational spectroscopi
J. Braz. Chem. Soc.. Publicado em: 2020-11
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4. Where’s the Spin? A DFT Study of Mixed-Valence Cyanide-Bridged Ruthenium Polypyridines
This article discusses the use of density functional theory (DFT) calculations in classifying and characterizing bimetallic ruthenium mixed-valence systems in terms of their electronic localization/delocalization degree. A standard B3LYP/LanL2DZ methodology including integral equation formalism-polarizable continuum model (IEF-PCM) solvent model is evaluated
J. Braz. Chem. Soc.. Publicado em: 2020-11
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5. Mackie B. Corra para ser feliz: como a corrida salvou minha vida. Rio de Janeiro: Harper Collins; 2019.
This article discusses the use of density functional theory (DFT) calculations in classifying and characterizing bimetallic ruthenium mixed-valence systems in terms of their electronic localization/delocalization degree. A standard B3LYP/LanL2DZ methodology including integral equation formalism-polarizable continuum model (IEF-PCM) solvent model is evaluated
Ciênc. saúde coletiva. Publicado em: 2020-11
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6. TÉCNICAS AVANÇADAS PARA A DIFERENCIAÇÃO DE ISÔMEROS POR ESPECTROMETRIA DE MASSAS
Mass spectrometry (MS) is a powerful and widespread technique but is inherently uncapable to differentiate species with same m/z ratio. For this reason, many classical approaches were developed based on differential fragmentation patterns in tandem MS. More recently, new techniques for isomer identification in MS were developed, and we highlight the photodis
Quím. Nova. Publicado em: 2020-09
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7. TITANYL SULPHATE, AN INORGANIC POLYMER: STRUCTURAL STUDIES AND VIBRATIONAL ASSIGNMENT
In this work, anhydrous titanyl sulfate (TiOSO4) was synthesized and characterized by elemental analyses and vibrational spectroscopy by the first time. In order to verify the stability of the crystallographic structure reported in the literature, an optimization calculation of the unit cell geometry was done with the CRYSTAL17 software, and the agreement wi
Quím. Nova. Publicado em: 05/12/2019
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8. ESQUARAÍNAS CIS E TRANS SUBSTITUÍDAS: APLICAÇÃO EXPERIMENTAL DA TEORIA DE GRUPO EM ESPECTROSCOPIA VIBRACIONAL
This work shows a practical application of the group theory to a relatively simple molecular system, as well its impact in the results obtained through vibrational spectroscopic techniques. Squaraines substituted by dicyanemethylene groups have been extensively studied, and after minor approaches in the sense to facilitate the point group determination, they
Quím. Nova. Publicado em: 05/12/2019
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9. Synthesis and characterization of mesoporous materials with SBA and MCM structure types
Resumo Materiais mesoporosos são estruturas promissoras para aplicação em catálise e adsorção devido à elevada área superficial e grande tamanho dos poros. Materiais mesoporosos foram sintetizados pelo método hidrotérmico com novos surfactantes, distintos daqueles observados na literatura, a fim de realizar um estudo de sua estrutura e obter materi
Cerâmica. Publicado em: 14/11/2019
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10. Differential Molecular Signature of Human Saliva Using ATR-FTIR Spectroscopy for Chronic Kidney Disease Diagnosis
Resumo Os sintomas da doença renal crônica (DRC) são frequentemente inespecíficos ou ausentes nos estágios iniciais desta doença. Desta forma, existe uma demanda para o desenvolvimento de plataformas com baixo custo, não-invasivas e com alta acurácia para o diagnóstico da DRC. Nós hipotetizamos que o nível dos componentes salivares se alteram pela
Braz. Dent. J.. Publicado em: 07/10/2019
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11. Linking gemology and spectral geology: a case study of elbaites from Seridó Pegmatite Province, Northeastern Brazil
Abstract reflectance spectroscopy is a fast tool for mineral identification and classification. We conducted spectral characterization of elbaite samples (n = 30) from Seridó Pegmatite Province, Borborema Province, NE Brazil, using a FieldSpec portable instrument and geochemical data from electron probe microanalysis. Visual interpretation of reflectance sp
Braz. J. Geol.. Publicado em: 13/05/2019
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12. Structural, optical and electrical properties of Ni-doped Co3O4 prepared via Sol-Gel technique
In this article, Nickel doped Cobalt oxide thin films and powders have been prepared on glass substrates using sol gel based dip coating process in order to investigate their optical, structural and electrical properties. The Ni concentration was changed from 0 to 9 wt(%).The synthesized samples were characterised by Ultraviolete visible analysis, X-ray diff
Mat. Res.. Publicado em: 07/02/2018