Spectroscopy
Mostrando 25-36 de 6190 artigos, teses e dissertações.
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25. Per-Aqueous Liquid Chromatography for the Separation of Polar Compounds Preparation and Characterization of Poly(ethylene oxide co dimethylsiloxane) Based Stationary Phase
Poly(ethylene oxide-co-dimethylsiloxane) was thermally immobilized on silica particles-Si(PEO)-to separate small polar compounds with water-rich mobile phases. Poly(ethylene oxide-co-dimethylsiloxane) content on Si(PEO) stationary phase was optimized using a central composite design. Infrared spectroscopy, scanning electron microscopy, and thermogravimetric
Journal of the Brazilian Chemical Society. Publicado em: 2022
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26. Synthesis and characterization of α-SnWO4 powders obtained by microwave-assisted hydrothermal method
Abstract The structural, morphological, and optical properties of α-SnWO4 synthesized by microwave-assisted hydrothermal method at 150 °C for different times were investigated. XRD revealed the formation of the orthorhombic phase, without the presence of a secondary phase. The sample processed for 64 min showed a reduction in unit cell volume, suggesting a
Cerâmica. Publicado em: 2022
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27. Biogenic synthesis of silver nanoparticles from thyme extract for functionalization of a bioactive glass produced from rice husk ash
Abstract The rice husk, agro-industrial residue, stands out for having silica, the main oxide former of the bioactive glass. To avoid contamination in this biomaterial, substances with bactericidal properties, like silver can be incorporated. Thus, the objective of this work is the synthesis of silver nanoparticles to functionalize a bioactive glass synthesi
Cerâmica. Publicado em: 2022
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28. Chemometric Evaluation of Poly(3-hexylthiophene) Electrochemical Aging Path as a Function of Electrochemical Synthesis Variables
Conductive polymers are versatile materials that can be applied in many different technology fields, especially green energy. They have several advantages, such as easy synthesis, low density, and cost. However, its electric conduction property is also related to material aging with great loss of their characteristics, limiting their applicability. The in-de
Journal of the Brazilian Chemical Society. Publicado em: 2022
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29. Structural Characteristics of Lignite Char from Different Pyrolysis Reactors and the Influence on Their Gasification Reactivity
The gasification reactivity of coal char is affected by numerous experimental variables, and char structure is one of the dominant factors. In this work, Raman spectroscopy, powder X-ray diffraction (XRD), and N2 adsorption were used to investigate the physical and chemical structure of char prepared under different pyrolysis conditions. Three kinds of pyrol
Journal of the Brazilian Chemical Society. Publicado em: 2022
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30. Atomic Absorption Spectrometry as an Alternative to Determine the Presence of Gold Nanoparticles on or in Silica Matrix
Two different gold-silica-based nanomaterials were prepared: (i) silica-supported gold nanoparticles (AuNP/SiO2); and (ii) gold-silica core-shell nanoparticles (AuNP@SiO2). Three strategies for sample treatment (S), consisting in acid treatments, were employed: (S1) HNO3; (S2) HNO3 + HCl; and (S3) HF + HNO3 + HCl, applying microwave oven digestion for S2 and
Journal of the Brazilian Chemical Society. Publicado em: 2022
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31. Assessment of Urban Contamination by Sewage in Sediments from Ipojuca River in Caruaru City, Pernambuco, Brazil
The Ipojuca River is considered the third most polluted river in Brazil due to the intense anthropogenic activities in the surrounding urban areas. The most important effluent is sewage discharge, which is responsible for considerable contamination. Traditional analyses (infrared spectroscopy, organic matter (OM), elemental analysis and granulometry) and adv
Journal of the Brazilian Chemical Society. Publicado em: 2022
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32. Simultaneous Quantification of Amorphous and Crystalline Valsartan in Tablets Using Raman Spectroscopy and Chemometrics Tools
Valsartan is an antihypertensive active pharmaceutical ingredient (API), it is used in the amorphous state in the commercial products. As amorphous materials are metastable, amorphous valsartan can crystallize to valsartan E, promoting changes in the dissolution and bioavailability of the drug. Tablets containing metastable forms of APIs need special conditi
Journal of the Brazilian Chemical Society. Publicado em: 2022
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33. Morphology Behavior of Copper Films Deposited after Wet Surface Treatment on Polished Alumina
In this paper, a pre-treatment process for electroless copper (Cu) deposition on the polished alumina (Al2O3) 99.9% and the behavior of Cu plating by electroless process after Al2O3 surface treatment were explored. Our work was carried out by changing the roughness of Al2O3 through micro-etching (coarsening), nucleation its surface by a two-step method (sens
Journal of the Brazilian Chemical Society. Publicado em: 2022
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34. CLOROFILA EXTRAÍDA DE RESÍDUO INDUSTRIAL DA ERVA-MATE (Ilex paraguaiensis) UMA POSSIBILIDADE DE ECONOMIA CIRCULAR
Chlorophyll is the most abundant green pigment on the planet, it is unstable and decomposes naturally. Mate-herb is a traditional native plant in the southern region of South America, and its tea is part of the local culture and extractive agriculture. The mate-herb industry generates as a by-product a resinous material rich in chlorophyll whose use is propo
Química Nova. Publicado em: 2022
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35. Eco-friendly multivariant green analytical technique for the estimation of ketoconazole by UV spectroscopy in bulk and cream formulation
The pharmaceutical industries are focusing on Green Analytical Chemistry principles like miniaturization, eco-friendly solvent usage, waste recycling, and analyst safety for sustainable results. A simple, eco-friendly sensitive and effective extraction and multivariant green analytical method to estimate ketoconazole in bulk and cream formulation were develo
Química Nova. Publicado em: 2022
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36. EFFECT OF REACTION CONDITIONS ON PARTICLE SIZE OF ZNO NANOPARTICLES VIA CONTROLLED PRECIPITATION METHOD AND IN-VITRO ANTIBACTERIAL CAPACITY
High-yield ZnO spheroidal nanoparticles with an average diameter around 23 nm (≈ 25% frequency) and 30 nm (≈ 28% frequency) were obtained by controlled semicontinuous precipitation at low temperatures. This synthesis was obtained from hydrozincite (Zn5(CO3)2(OH)6) as primary nanoparticles. The Zn5(CO3)2(OH)6 nanoparticles were synthesized by hydrolysis o
Química Nova. Publicado em: 2022