Libs
Mostrando 1-12 de 32 artigos, teses e dissertações.
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1. A química analítica aplicada aos estudos de pigmentos rupestres: uma revisão
Instrumental advances have been employed in the study of archeological remains such as prehistoric rupestrians paintings with the objective of chemically characterizing them in order to reconstruct the cultural technologies of a prehistoric human group and/or to support conservation science studies. The analytical techniques most commonly used in archaeometr
Química Nova. Publicado em: 2022
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2. Calibration Strategies Applied to Laser-Induced Breakdown Spectroscopy: A Critical Review of Advances and Challenges
Over the years, laser-induced breakdown spectroscopy (LIBS) has been reported in the literature as an alternative to traditional methods of analysis, becoming well established among spectroanalytical techniques. LIBS is a technique widely used for qualitative approaches; however, it is necessary considerable effort for use in quantitative analysis, mainly du
J. Braz. Chem. Soc.. Publicado em: 2020-12
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3. Direct Analysis of Human Hair Before and After Cosmetic Modification Using a Recent Data Fusion Method
The cosmetic modification of hair is a very common procedure used to mask or cover evidence at a crime scene. Deoxyribonucleic acid (DNA) tests are expensive and require good-quality collection of samples and a database profile. To overcome these challenges, direct analysis was performed on a large set of hair strands collected from individuals, denoted orig
J. Braz. Chem. Soc.. Publicado em: 2020-01
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4. LASER INDUCED-BREAKDOWN SPECTROSCOPY (LIBS): HISTÓRICO, FUNDAMENTOS, APLICAÇÕES E POTENCIALIDADES
This review attempts to present a broad view of the technique laser-induced breakdown spectroscopy (LIBS), since its origin, fundamentals, sample preparation strategies, use of chemometric tools for data processing, the advantages and limitations with regard to qualitative and quantitative analysis, aplications and future trends as an analytical technique th
Quím. Nova. Publicado em: 18/07/2019
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5. Combination of Multi-Energy Calibration (MEC) and Laser-Induced Breakdown Spectroscopy (LIBS) for Dietary Supplements Analysis and Determination of Ca, Mg and K
This study describes the application of laser-induced breakdown spectroscopy (LIBS) for the direct determination of Ca, K and Mg in powdered dietary supplements. Multi-energy calibration (MEC) method was applied to obtain a calibration curve. With MEC, it was possible to observe spectral interferences and select adequate emission lines from LIBS. For Ca and
J. Braz. Chem. Soc.. Publicado em: 2019-04
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6. Qualitative and Quantitative Chemical Investigation of Orthopedic Alloys by Combining Wet Digestion, Spectroanalytical Methods and Direct Solid Analysis
In this study, two laser-based techniques, laser-induced breakdown spectroscopy (LIBS) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used for analytical signal evaluation of Ti, Al, and V and investigation of possible harmful elements eventually present as minor elements in Ti alloys. Due to the lack of certified reference
J. Braz. Chem. Soc.. Publicado em: 2018-04
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7. Comparison of ICP OES and LIBS Analysis of Medicinal Herbs Rich in Flavonoids from Eastern Europe
Essential and toxic metals were determined in eighteen samples of medicinal herbs from Poland, Lithuania and Serbia by means of laser-induced breakdown spectroscopy (LIBS) and inductively coupled plasma optical emission spectrometry (ICP OES). Calcium, K and Mg concentrations were obtained in % (m/m) and other metals (Na, Co, Cu, Fe, Mn, Ni, Zn, Cd, Cr and P
J. Braz. Chem. Soc.. Publicado em: 2017-05
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8. Fabrication of Cathode Materials Based on Limn2o4/Cnt and Lini0.5mn1.5o4/Cnt Nanocomposites for Lithium – Ion Batteries Application
AbstractCarbon nanotubes (CNTs) are a promising candidate material for use in lithium batteries due to 1D tubular structure, high electrical, thermal conductivities, and extremely large surface area. In this work, the MWCNTs were purified by dispersion in a mixture of HNO3 and H2SO4acids. The oxidized-MWCNTs were used as conducting addition to prepare a nano
Mat. Res.. Publicado em: 2015-10
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9. LIBS e nanopartículas fluorescentes : novas estratégias para determinação de íons Cu(II) em águas / LIBS and fluorescent nanoparticles : new strategies for the determination of Cu(II) ions in water
Neste trabalho diferentes fases sensoras foram desenvolvidas para implementar novas estratégias para a determinação de íons cobre em águas naturais, empregando Espectroscopia Óptica de Emissão em Plasma Induzido por Laser (LIBS) e Espectroscopia de Luminescência. Nas determinações por LIBS, membranas de PVC plastificadas foram empregadas para extra
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/04/2012
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10. Multivariate treatment of LIBS data of prehistoric paintings
Dois fragmentos de pinturas rupestres pertencentes a dois sítios arqueológicos brasileiros, sendo um no estado do Piauí (Sítio Toca da Extrema II) e outro no estado do Rio Grande do Norte (Sítio arqueológico Xique-Xique), foram analisados por LIBS (espectroscopia de emissão em plasma induzido por laser). Um instrumento construído no laboratório (las
Journal of the Brazilian Chemical Society. Publicado em: 2012-05
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11. Discriminação de alface orgânicas e convencionais usando determinação elementar e métodos quimiométricos / Discrimination of organic and conventional lettuce using elemental determination and chemometrics methods
Alimentos como os vegetais podem ser cultivados de diferentes maneiras (orgânica, convencional e hidropônica). Na era dos agrotóxicos cresce a procura pelos alimentos orgânicos, os quais são cultivados em terra fértil sem uso de fertilizantes químicos inorgânicos ou produtos agrotóxicos. Uma vez que esses alimentos orgânicos necessitam de um cultiv
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/02/2011
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12. Efeito da fluência na análise de pastilhas de materiais vegetais por espectrometria de emissão óptica com plasma induzido por laser / Effect of fluence on laser induced breakdown spectrometry analysis of pellets of plant materials
A espectrometria de emissão óptica com plasma induzido por laser (LIBS) constitui um método alternativo para a determinação simultânea de macro e micronutrientes em pastilhas de materiais vegetais. No entanto, pouca informação com relação às condições de fluência e de focalização do laser mais apropriadas para a análise de pastilhas de mater
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 10/02/2011