Uv Excitation
Mostrando 1-12 de 76 artigos, teses e dissertações.
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1. 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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2. A novel fluorescence sensor for the detection of chloride ion in artificial sweat and environmental water with nitrogen-doped graphene quantum dots
A new fluorescent detection route for chloride ion was designed with Nitrogen-doped graphene quantum dots (N-GQDs), which were prepared by a traditional hydrothermal method with citric acid as carbon source and urea as nitrogen source. The prepared N-GQDs solution was light yellow, and the freeze-dried solid was black. It emitted blue light under ultraviolet
Química Nova. Publicado em: 2022
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3. Incorporation of Fluorescent Dyes in Electrospun Chitosan/Poly(ethylene oxide)
Polymeric films have been increasingly investigated due to the ease of miniaturization and integration in several sensor devices. Films obtained from the electrospinning technique have a controlled diameter and homogeneity, and substances can be incorporated into the polymeric network. Electrospinning fiber of chitosan (Ch) and poly(ethylene oxide) (PEO) was
J. Braz. Chem. Soc.. Publicado em: 2021-05
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4. Blue Glow Sticks: Cinnamic Acids and Arylacrylonitriles with Liquid-Crystalline Properties and Highly Fluorescent
Five new π-conjugated chromophores derived from acrylic acid and acrylonitrile were synthesized and their thermal and photophysical behaviors were analyzed. They were designed and synthesized through Knoevenagel condensations between arylacetylenebenzaldehydes and a methylene group activated from cyanoacetic and malonic acids. The characterization of the ta
J. Braz. Chem. Soc.. Publicado em: 2021-01
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5. Preparation of Fluorescent Carbon-Based Dots from Waste Tire Pyrolysis
The pyrolysis of waste tire has been proposed as an alternative route to its recycling producing residual oils that can be used as fuels. In this work, a physicochemical process to obtain carbon-based dots (CBD) from carbon black (CBL) derivatives of tires is described. For this, the CBL was treated with different acids to produce CBL1 and CBL2 particles sus
J. Braz. Chem. Soc.. Publicado em: 2020-11
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6. UNRAVELING THE SOLVATOCHROMISM OF A TRIARYLMETHANE DYE BY RESONANCE RAMAN SPECTROSCOPY
The effect of the solvent on the electronic properties of the triarylmethane dye rosolic acid (RA) is investigated by means of UV-VIS and resonance Raman (RR) spectroscopies. The comparison of the solvatochromic behavior of both neutral and dianionic species of RA in acetonitrile, dimethylsulfoxide, and methanol illustrates the effect of polarity and hydroge
Quím. Nova. Publicado em: 05/12/2019
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7. Hydrothermal Synthesis to Water-stable Luminescent Carbon Dots from Acerola Fruit for Photoluminescent Composites Preparation and its Application as Sensors
Carbon dots (C-dots) possess the attractive properties of high stability, low toxicity, good water solubility, simple synthetic routes as well as size and excitation-dependent photoluminescence (PL).The aim of this work was to synthesize photoluminescent C-dots by hydrothermal method using acerola fruit (Malpighiaemarginata) as a row material, since this fru
Mat. Res.. Publicado em: 06/06/2019
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8. Co3O4-ZnO P-N Heterostructure Nanomaterials Film and its Enhanced Photoelectric Response to Visible Lights at Near Room Temperature
In this paper, Co3O4-ZnO nanomaterials with Co3O4 doping mass fractions of 0%, 2.13%, 4.13%, and 6.13% were prepared by sol-gel method. In order to explain and confirm the influence of the incorporation of Co3O4 on the surface morphology and gas sensitivity of ZnO at a relatively low gas concentration, additional studies such as XRD, XPS, SEM, EDS and UV-vis
Mat. Res.. Publicado em: 11/04/2019
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9. Fluorescent Sensors Based on Cu-Doped Carbon Quantum Dots for the Detection of Rutin
In this paper, Cu-doped carbon quantum dots (Cu-CQDs) were prepared by carrying out thermolysis of Na2[Cu(EDTA)] and hydroxylamine hydrochloride at 300 ºC for 2 h. The as-prepared Cu-CQDs were characterized by UV-Vis, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diff
J. Braz. Chem. Soc.. Publicado em: 08/04/2019
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10. Photophysical and Photochemical Properties and Aggregation Behavior of Phthalocyanine and Naphthalocyanine Derivatives
The photophysical and photochemical properties of phthalocyanine and naphthalocyanine with similar structures were studied in solution and with density-functional theory (DFT) computational method. The extended π-conjugated system in naphthalocyanines causes a bathochromic shift in UV-Vis, emission and excitation bands, and promotes lesser generation of sin
J. Braz. Chem. Soc.. Publicado em: 2018-06
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11. Synthesis and Characterization of Non-Linear Optical Crystal of Manganese Mercury Thiocyanate Glycol Monomethyl Ether
The design and synthesis of organic nonlinear optical (NLO) crystals are a promising area of current research in materials science. Organic materials are found to possess better non linear optical properties when compared to inorganic materials. Recently, there has been a widespread interest in the metal-organic coordination compounds, which are a combinatio
Mat. Res.. Publicado em: 30/11/2017
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12. Dielectric Behavior of Alginate-Based Hydrogel Containing Neomycin-Loaded Lipid Nanovesicles under Influence of Electrical Potentials
Dielectric characterization has been applied as a convenient tool for evaluation of transport and polarization mechanisms in soft materials. In this work, we have explored the study of charge transport mechanisms in alginate hydrogel containing neomycin-loaded liposomes. For comparison, drug release kinetic was evaluated by using UV-Vis spectrophotometry and
J. Braz. Chem. Soc.. Publicado em: 2016-01