Ultraviolet Spectra
Mostrando 1-12 de 165 artigos, teses e dissertações.
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1. Characterization of Commercially Available Turmeric for Use in Pharmaceutical Products and Food Supplements
We addressed some physicochemical and biological differences in commercial turmeric, acquired from both handling pharmacies and stores selling natural products for quality assessment. For this, it was determined the melting point, antioxidant activity by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), antimicrobial activity via the agar disk-diffusion assay,
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Synthesis, Characterization, Absorption and Fastness Properties of Novel Monoazo Dyes Derived from 1-Phenyl-3-amino-4-(2-thiazolilazo)pyrazol-5-one
Monosubstitute thiazolyl amines were diazotized in acetic acid, coupled to 1-phenyl-3-aminopyrazol-5-one (1a-1c) and acetylated to obtain the 2a-2c dyes. The dyes were characterized by elemental analysis and spectroscopic (Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), ultraviolet (UV)) methods. The effects on the visible absorption spe
J. Braz. Chem. Soc.. Publicado em: 2020-09
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3. Preparation of novel blue phosphate pigments in imitation of turquoise
Resumo Como novo pigmento azul, vários fosfatos hidratados de cobre e alumínio imitando turquesa, CuAl6(PO4)4(OH)8.4H2O, foram preparados misturando solução de nitrato de cobre, solução de nitrato de alumínio, ácido fosfórico e solução de hidróxido de sódio. Amostras com composição química semelhante à turquesa foram preparadas. Os pós obti
Cerâmica. Publicado em: 14/11/2019
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4. Photodegradation Mechanisms on Poly(ε-caprolactone) (PCL)
Photodegradation of PCL was performed exposing injected specimens to ultraviolet radiation (UV-B) up to 9 weeks. Photodegradated PCL specimens were tested by Differential Scanning Calorimetry (DSC), Infrared Spectroscopy (FTIR), mechanical properties, Optical Microscopy (MO) and Scanning Electron Microscopy (SEM).Upon exposure decrease in elongation at break
Mat. Res.. Publicado em: 16/07/2018
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5. Effect of Different Synthesis Methods on the Textural Properties of Calcium Tungstate (CaWO4) and Its Catalytic Properties in the Toluene Oxidation
Calcium tungstate (CaWO4) crystals were prepared by microwave-assisted hydrothermal (MAH) and polymeric precursor methods (PPM). These crystals were structurally characterized by X-ray diffraction (XRD), N2 adsorption, X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) measurements. The morphology and size of
Mat. Res.. Publicado em: 16/04/2018
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6. Solid-Phase Peptide Synthesis of Dipeptide (Histidine-β-Alanine) as a Chelating Agent by Using Trityl Chloride Resin, for Removal of Al3+, Cu2+, Hg2+ and Pb2+: Experimental and Theoretical Study
Solid-phase peptide synthesis of dipeptide (histidine-β-alanine) as a chelating agent examined by common N-9-fluorenylmethyloxycarbonyl-N-trityl-L-histidine and tert-butyloxycarbonyl-β-alanine-OH amino acid derivatives. Trityl chloride resin was used as a carrier resin. The molecular structure of the dipeptide was definite by using different methods such a
J. Braz. Chem. Soc.. Publicado em: 2016-10
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7. Structural, Optical and Photocatalytic Properties of Co-Tio2 Prepared by Sol-Gel Technique
In the present work, the Co/TiO2 nanocomposite was prepared by sol-gel method. The structural and optical properties of nanocomposite were studied using, X-ray diffraction (XRD) and diffuse reflectance UV-VIS spectrometry. The XRD spectra revealed its tetrahedral anatase structure. The grain size and optical properties of composite are also reported. Syntesi
Mat. Res.. Publicado em: 10/05/2016
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8. Novel Ag3PO4/CeO2 p-n Hierarchical Heterojunction with Enhanced Photocatalytic Performance
The composite Ag3PO4/CeO2 photocatlyst, a novel p-n type heterojunction, has been successfully fabricated through a facile hydrothermal process combined with a successive in situ precipitation technique. The X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and UV-visible diffuse reflectance
Mat. Res.. Publicado em: 26/04/2016
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9. Synthesis and Characterization of Nb2O5:La3+,Eu3+ Phosphors Obtained by the Non-Hydrolytic Sol-Gel Process
The phosphor-converted light-emitting diode technique is an important solid-state illumination strategy. Sulfide-based materials are the most often employed red phosphors, but they are chemically unstable and present lower efficiency in comparison to the blue and green phosphors. Therefore, it is important to find a new red phosphor source that can emit inte
J. Braz. Chem. Soc.. Publicado em: 2015-12
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10. NIR Luminescence from Sol-Gel Er3+ Doped SiO2:GeO2 Transparent Gels, Nanostructured Powders and Thin Films for Photonic Applications
Samples of (1 – x)SiO2:xGeO2 compositions, containing x = 10 and 20, and doped with Er3+, were prepared by a simple sol-gel route. Homogeneous and transparent gels were synthesized and xerogels were obtained by gel annealing from 700 ºC to 1100 ºC. Films exhibiting high transmittance in the visible and near infrared were deposited by spin-coating techniq
J. Braz. Chem. Soc.. Publicado em: 2015-12
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11. Comparison between Ultraviolet and Infrared Spectroscopies for the Simultaneous Multivariate Determination of Pyrantel and Praziquantel
Methods based on multivariate calibration and diffuse reflectance infrared Fourier transform (DRIFT) and ultraviolet (UV) spectroscopies were developed for the simultaneous determination of two veterinary pharmaceutical drugs, pyrantel pamoate and praziquantel, in commercial tablets. The best UV model was obtained with the full spectra, 200-400 nm, and pa
J. Braz. Chem. Soc.. Publicado em: 2015-07
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12. FUNDAMENTOS DE ELETROFORESE CAPILAR: UMA ABORDAGEM POR ANIMAÇÕES
Among the analytical separation techniques, capillary electrophoresis (CE) has attracted attention in both academic and industrial fields, mainly owing to its efficiency, short analysis times, low reagent consumption and residue generation. This is also the case in Chemistry courses, books and papers, demonstrating CE´s well-established status. However,
Quím. Nova. Publicado em: 2015-06