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331.
Valdeir A. Silva José W. Silva Paulo C. de Morais Noelio O. Dantas 《Brazilian Journal of Physics》2018,48(2):119-125
Bayesian inference was used as a new approach to calculate of rare earth (RE) ion spectroscopic parameters within the Judd?Ofelt theory using the Li2O-B2O3-Al2O3 glass system doped with Nd2O3 and TiO2. This system was synthesized by the fusion method, and the physical properties of the as-synthesized material were investigated. Optical absorption, photoluminescence, micro-Raman, mass density, refractive index, and radiative lifetime calcuations were performed. We investigated the effects of crystal field changes on Nd3+-ions caused due to co-doping with increasing TiO2 content. We observed that co-doping with TiO2 altered the radiative transition rates A(J,J′), favored symmetry enhancement around the Nd3+-ions, and promoted the onset of vibrational modes, contributed to the attenuation of O-H bonds, and substantially increased the spectroscopic quality, χ. 相似文献
332.
N.O. Dantas L. Damigo Fanyao Qu R.S. Silva P.P.C. Sartoratto K.L. Miranda E.C. Vilela F. Pelegrini P.C. Morais 《Journal of Non》2008,354(42-44):4727-4729
Chemical precipitation of metal-ions from aqueous solution has been successfully used to produce Zn1?xMnxO nanocrystals, in the form of nano-powder. X-ray diffraction (XRD) measurements reveal that the as-prepared samples are single-phase materials and their lattice constant changes with the variation of Mn-concentration, which indicates the incorporation of Mn2+ into the hosting ZnO. These findings are corroborated by the observation of the well defined six hyperfine lines of Mn2+ ion in the electron paramagnetic resonance (EPR) spectra of the samples with a low Mn-concentration, and of a broad EPR line, which manifests the onset of Mn–Mn exchange interaction, in the samples with an elevated value of x. 相似文献
333.
Q. S. Ferreira S. W. da Silva C. M. B. Santos G. C. Ribeiro L. R. Guilherme P. C. Morais 《Journal of Raman spectroscopy : JRS》2015,46(9):765-771
In this study, the surface‐enhanced Raman spectroscopy (SERS) technique was used to asses key information regarding the surface adsorption of Rifampicin (RIF) onto magnetite nanoparticle previously dressed with a bilayer of lauric acid (LA). The effects of white light illumination on the physicochemical properties of the RIF molecule were also investigated. Transmission electron microscopy, dynamic light scattering, zeta‐potential, and Fourier transform infrared spectroscopy were also employed to characterize the investigated materials. Vibrational mode assignments for the SERS spectra and comparison between the data recorded from the free and adsorbed RIF provided insights for the adsorption of this biomolecule onto the LA‐bilayer dressed magnetite nanoparticle. The results suggested that the species binding to the outer carboxylate group of the LA‐bilayer is more likely the piperazine nitrogen adjacent to the imine nitrogen. The SERS data also revealed the enhancement of the RIF molecule stability to white light irradiation while adsorbed onto the magnetite nanoparticle. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献