952 resultados para Europium and aluminum ions


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Mixed calcium and copper oxalates, with different proportions of Ca2+ and Cu2+ ions, were precipitated by dimethyl oxalate hydrolysis in homogeneous solution. The compounds were evaluated by means of scanning electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetry (TG), and differential thermal analysis (DTA). The results suggested quantitative precipitation without solid solution formation. From the TG and DTA curves, it was possible to evaluate the Ca2+ ion proportion in the solid phase and to confirm the precipitation of the individual species.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This research shows the influence of the synthesis route in the structural and morphological characteristics as well as in the luminescent properties of doped with europium and pure SrTiO3 (STO) powders prepared by microwave assisted hydrothermal synthesis, MWH, and by the polymeric precursor method, PPM. The XRD at room temperature of the STO powders nominally pure obtained by PPM at 700°C for 3 hours, as well as by the MWH at 190°C by 30 minutes present all the reflection peaks for the cubic perovskite structure (JCPDS-ICDD 35-734). The morphology varies according to the synthesis route. The particles of pure STO obtained by PPM presents morphology in the form of plates and the morphology of the particles synthesized by MWH is spherical with approximately 150 nm. The photoluminescent analysis shows for pure STO wide bands associated with the transition of charge transfer from the titanates group (TiO3)2- that are centered on 450 nm. In both preparation methods the emission bands obtained in the composites spectra were found to be asymmetric and low intense. However, in the case of the STO prepared by the PPM a bigger FWHM of the band can be observed. The excitation of the samples was done using a laser (Coherent Innova) with wavelength of 350 nm.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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One of the areas of human identification is Cheiloscopy, the name given to the study of the lips, their characteristics (such as thickness, position of the grooves and grooves) and the record of the impressions left by them. There are variations in the layout of the lines and fissures of the lips, which are unique to each individual, permanent and unchanging. The lip print rarely changes, enduring minor traumas such as inflammation or sores. In criminal investigations, lip prints, visible through the presence of lipstick, can be found on glasses, napkins, clothes, cigarettes, indicating a relationship between the subject and the scene of the crime. Latent impressions may be revealed employing specific chemicals such as powder of silver and aluminum nitrate. Although it is not a very common method, Cheiloscopy may become very useful in forensics due to the extensive amount of valuable information that it brings. The objective of this study was to review the literature on the use of Cheiloscopy in human identification, using traditional and digital methods. It was found that the literature is still in need of studies in this area. The advent of new digital technologies can facilitate the implementation of technical expertise, generating speed and objectivity. New research studies are necessary, especially in the development of digital methods. The application of Cheiloscopy can greatlyhelp with Law, in the identification of living suspects and dead individuals. In the end the benefit will fall to society as a whole.

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The aim of this study was to evaluate the physicochemical properties and bioactivity of two formulations of calcium silicate-based cements containing additives (CSCM) or resin (CSCR), associated with radiopacifying agents zirconium oxide (ZrO2) and niobium oxide (Nb2O5) as micro- and nanoparticles; calcium tungstate (CaWO4); and bismuth oxide (Bi2O3). MTA Angelus was used as control. Methods. Surface features and bioactivity were evaluated by scanning electron microscopy and the chemical composition by energy dispersive X-ray spectrometry (EDS-X). Results. CSCM and CSCR presented larger particle sizes than MTA. Hydroxyapatite deposits were found on the surface of some materials, especially when associated with the radiopacifier with ZrO2 nanoparticles. All the cements presented calcium, silicon, and aluminum in their composition. Conclusion. Both calcium silicate-based cements presented composition and bioactivity similar to MTA when associated with the radiopacifiers evaluated.

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Orthodontic mini-implants are used in clinical practice to provide efficient and aesthetically-pleasing anchorage. AIM: To evaluate the hardness Vickers hardness and chemical composition of mini-implant titanium alloys from five commercial brands. METHODS: Thirty self-drilling mini-implants, six each from the following commercial brands, were used: Neodent NEO, Morelli MOR, Sin SIN, Conexão CON, and Rocky Mountain RMO. The hardness and chemical composition of the titanium alloys were performed by the Vickers hardness test and energy dispersive X-ray spectroscopy, respectively. RESULTS: Vickers hardness was significantly higher in SIN implants than in NEO, MOR, and CON implants. Similarly, VH was significantly higher in RMO implants than in MOR and NEO ones. In addition, VH was higher in CON implants than in NEO ones. There were no significant differences in the proportions of titanium and aluminum in the mini-implant alloy of the five commercial brands. Conversely, the proportion of vanadium differed significantly between CON and MOR/NEO implants. CONCLUSIONS: Mini-implants of different brands presented distinct properties of hardness and composition of the alloy.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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