Spectroscopy
Mostrando 1-12 de 6190 artigos, teses e dissertações.
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1. Bimetallic Au-Pd/α-MoO3 Catalyst with High Oxygen Vacancies for Selective Oxidation of Cinnamyl Alcohol
Supported Au-Pd nanoparticles (NPs) have been extensively studied in alcohol oxidation reactions. However, few studies use reducible metal oxides as support, which can activate oxygen molecules and boost the selectivity of the reaction. In this work, Au-Pd NPs were supported on α-MoO3 and evaluated in the selective oxidation of cinnamyl alcohol without solv
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Study of rhombohedral tricalcium phosphate in hexagonal crystal structure family on the sample prepared by the sol-gel route and the effect of calcination temperature
Abstract The effect of the calcination temperature at 800 and 1000 °C on the stable formation of the tricalcium phosphate with rhombohedral structure in the system of the hexagonal crystal family was determined, while its precursor was made from limestone obtained from nature in the Lumajang district, Indonesia. The rhombohedral tricalcium phosphate samples
Cerâmica. Publicado em: 2023
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3. Catalysts Derived from Thermal Treatments of Hydrocalumite-Type Compounds: Synthesis and Application in Transesterification Reactions
Catalyst performance is a relevant factor in biodiesel production because it can affect the efficiency of the process. This work provides a study of the performance of heterogeneous catalysts for biodiesel production derived from thermal-treated hydrocalumite-type compounds. This work aimed to synthesize and characterize hydrocalumite-type compounds intercal
Journal of the Brazilian Chemical Society. Publicado em: 2023
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4. Carbon Dots from Pilosocereus gounellei for Fluorimetric Determination of Tannin in Tea Using a Flow-Batch System
In this study, xiquexique (Pilosocereus gounellei) native endemic cactus from the Brazilian semiarid was used for the first time as a natural carbon source (“green precursor”) for the synthesis of highly fluorescent carbon dots (CDs). These CDs were successfully used to develop a fast, low-cost, eco-friendly fluorescence method for the determination of t
Journal of the Brazilian Chemical Society. Publicado em: 2023
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5. Synthesis of delafossite CuCrO2 via solution combustion method and its acid functionalization for biodiesel production
Abstract CuCrO2 was synthesized by solution combustion synthesis (SCS) and applied as a heterogeneous catalyst to produce soybean biodiesel. The combustion reaction was carried out using urea as a fuel, and copper (II) and chromium (III) nitrates as precursors. After the powders’ obtention, these were calcined and functionalized in an acidic medium. The po
Cerâmica. Publicado em: 2023
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6. Study of Catalytic Pyrolysis of Biomass Sorghum (Sorghum bicolor L. Moench) Using Design of Experiments and Surface Response Methodology
This study proposes a screen of variables that have an influence on the modification of the bio-oil chemical composition as a unique critical quality attribute (CQA) throughout the pyrolytic process (zeolite, ZSM-5) by using a 24 full factorial design, followed by optimization through a response surface methodology (RSM) based on central composite design (CC
Journal of the Brazilian Chemical Society. Publicado em: 2023
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7. 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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8. Enhancement of Visible Light-Responsive Photocatalytic Efficiency by Using a Laccaic Acid-Modified Titanium Dioxide Photocatalyst
In this study, a laccaic acid-modified TiO2 photocatalyst (Lac-TiO2) was prepared via an impregnation method with 0.50, 1.00, 2.50, and 5.00 wt.% laccaic acid. The products’ physical properties were examined through X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoemission spectroscopy (XPS), UV-Vis diffused
Journal of the Brazilian Chemical Society. Publicado em: 2022
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9. Proton spectroscopy: a simple and useful tool in the investigation of mitochondrial disease
Arquivos de Neuro-Psiquiatria. Publicado em: 2022
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10. Study of nanocomposites with carbon nanotubes and their tendency for carbon organization
Abstract The carbon derived from the thermal treatment of modified phenolic resins (PR) tends to organize into graphitic lamellae or turbostratic carbon and is commonly considered non-graphitizable. In this study, nanocomposites were synthesized with modified phenolic resin (Novolac) used as the matrix and oxidized multi-walled carbon nanotubes (NTox) in amo
Cerâmica. Publicado em: 2022
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11. QUANTITATIVE SPECIATION OF THE LIQUID PHASE BY FTIR SPECTROSCOPY IN THE SYSTEM AMP-PZ-CO2-H2O
This work reports a multivariate calibration partial least square regression (PLS) model to quantify the liquid-phase concentrations of 2-amino-2-methyl-1-propanol (AMP), piperazine (PZ), bicarbonate, PZ monocarbamate, and PZ dicarbamate during the absorption/desorption process by Fourier Transform Mid-Infrared spectroscopy (mid-FTIR). The model could predic
Química Nova. Publicado em: 2022
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12. Thermostimulated crystal structure transformation of the polymineral clay submicron particles
Abstract Changes in the structure of phyllosilicate microparticles of submicron fractions of polymineral clay with an average size of 290 nm, as well as changes in the positions of impurity ions of transition metals in the crystal lattice, were studied by X-ray diffraction analysis, Fourier transform infrared spectroscopy, and high-resolution electron parama
Cerâmica. Publicado em: 2022