Absorption Spectra
Mostrando 13-24 de 728 artigos, teses e dissertações.
-
13. DEVELOPMENT OF AN ANALYTICAL METHOD FOR THE DETERMINATION OF LEAD BASED ON LOCAL SURFACE PLASMON RESONANCE OF SILVER NANOPARTICLES
Lead is environmental pollutant that even in low trace is harmful for human health and wildlife. In this study we presented a colorimetric method for determination of Pb2+ in water by aggregation of silver nanoparticles capped citrate in the presence of deferoxamine as chelating agent. Silver nanoparticles were prepared by reduction of AgNO3 with NaBH4. In t
Quím. Nova. Publicado em: 2020-06
-
14. Influencia del ácido ascórbico en el crecimiento de nanorods de oro con banda de plasmón longitudinal en el infrarrojo cercano-NIR
ABSTRACT The present work reports the ascorbic acid effect (0,60-0,98 µM) on the aspect ratio (AR) of gold nanorods with bands of longitudinal plasmon (LP) in the near infrared (958 -1085 nm), grown by seed-mediated chemical route. Cloroauric acid-1mM as precursor agent was used, obtained from a stock solution prepared by dissolving metallic gold (99,99%) i
Matéria (Rio J.). Publicado em: 16/09/2019
-
15. EXTRATO DE HIBISCO-COLIBRI COMO INIBIDOR VERDE DE CORROSÃO DO AÇO-CARBONO EM ÁCIDO SULFÚRICO
For this work, a hydroalcoholic extract was prepared from the aerial parts of the Malvaviscus arboreus (Malvaceae) species, popularly known as hibisco-colibri in Brazil; and then, investigated by infrared and NMR spectroscopy. A class of special metabolites containing a porphyrin skeleton and pyrrole units was determined by typical absorption spectra, mainly
Quím. Nova. Publicado em: 26/08/2019
-
16. Mineralogical and gemological characterization of emerald crystals from Paraná deposit, NE Brazil: a study of mineral chemistry, absorption and reflectance spectroscopy and thermal analysis
Abstract The Paraná deposit, located at Southwestern Rio Grande do Norte state, in Brazil, is one of the few emerald deposits found at Borborema Province. The mineralization occurs in phlogopite schists and actinolite-phlogopite schists associated with pegmatites and albitites within the Portalegre Shear Zone. Unlike other well-known Brazilian emerald depos
Braz. J. Geol.. Publicado em: 22/08/2019
-
17. Ligand and Solvent Effects on the Structural and Optical Properties of Au13L83+ Clusters: a Density Functional Theory Study
Density functional theory (DFT) calculations have been performed to develop a systematic structural analysis of Au13L83+, where L = SCH3, SeCH3, SCH2OCH3 and S(CH2)2NH2, in order to examine the influence of different ligands. Binding energy calculations indicate that the gold core is more stabilized by the ligand in the following sequence S(CH2)2NH2 > SCH2OC
J. Braz. Chem. Soc.. Publicado em: 04/07/2019
-
18. 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
-
19. Espectroscopia óptica de baixo custo: uma estratégia para a introdução de conceitos de física quântica no ensino médio
Resumo Neste artigo, reportamos a confecção e discutimos a aplicabilidade de um espectrômetro óptico de baixo custo como recurso didático para a introdução de conceitos de Física Quântica no ensino médio. O protótipo foi desenvolvido usando grade de difração comercial, lentes convergentes (lupas), webcam e o software Tracker para extração dos
Rev. Bras. Ensino Fís.. Publicado em: 29/04/2019
-
20. Quantum Chemical Investigation of the Intramolecular Copigmentation Complex of an Acylated Anthocyanin
Anthocyanins are the natural plant pigments responsible for most of the red, blue and purple colors of flowers and fruit. One method of stabilization of the color of anthocyanins in nature is intramolecular copigmentation, in which a copigment molecule covalently attached to one of the sugar residues complexes with the anthocyanin cation chromophore. In the
J. Braz. Chem. Soc.. Publicado em: 2019-03
-
21. Water-Soluble Benzazole Dyes Fluorescent by ESIPT: Structural Characterization, Photophysical Properties and Its Application as a Probe for Direct Staining of Helminths
A series of four water-soluble benzazole dyes that emit fluorescence by the excited state intramolecular proton transfer (ESIPT) mechanism were structurally characterized by Fourier transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance (NMR) attached proton test (APT) and mass spectrometry. Their photophysical properties were systemat
J. Braz. Chem. Soc.. Publicado em: 2019-03
-
22. Optimización de un procedimiento para la determinación de oro mediante espectrofotometría UV/Vis
ABSTRACT The main objective of the research group is the recovery of valuable metals (contained in PCB’s) such as Cu, Au, Ag, Pt, Pd, etc., by hydrometallurgical alternatives to the current ones used in mining. One of the biggest difficulties that has encountered the research group is the lack of availability of an adequate, simple and reliable quantitativ
Matéria (Rio J.). Publicado em: 19/07/2018
-
23. Changes in the crystalline degree in neutron irradiated EPDM viewed through infrared spectroscopy and inelastic neutron scattering
ABSTRACT The changes in the degree of crystallinity in commercial Ethylene Propylene Diene rubber-type M (EPDM) irradiated with neutrons at different doses has been studied by means of inelastic neutron scattering and infrared absorption spectroscopy experiments. EPDM samples were taken from the housing of non-ceramic electrical insulators which are used in
Matéria (Rio J.). Publicado em: 19/07/2018
-
24. Structural, Thermal, Optical, and Photoacoustic Study of Mechanically Alloyed Nanocrystalline SnTe
A nanostructured SnTe phase was produced by mechanical alloying after 2 h of milling. Part of the as-milled powder was annealed and its X-ray diffraction (XRD) pattern was recorded. The XRD patterns of the as-milled and annealed samples were refined using the Rietveld method. After annealing, partial decomposition of the SnTe phase was observed and corrobora
Mat. Res.. Publicado em: 07/06/2018