Graphene
Mostrando 13-24 de 104 artigos, teses e dissertações.
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13. 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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14. Drawing Electrochemical Sensors Using a 3D Printing Pen
This communication demonstrates that a 3D printing pen, commercially-available as a toy for kids, can be used to draw thermoplastic electrochemical sensors using conductive filaments over any desirable format and substrate. A polylactic acid filament containing graphene or carbon black was passed through the 3D pen that works as a handheld 3D printer (fused
J. Braz. Chem. Soc.. Publicado em: 2020-09
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15. Synthesis, Characterization, and Synergic Photocatalytic Activity of Amorphous TiO2/Chitosan Carbon Microspheres
In this work, we report the synthesis and characterization of new amorphous graphene-like TiO2/chitosan carbon microspheres and its performance as photocatalyst. Four different carbon chitosan microspheres materials were obtained based on the distinctive procedure to incorporate TiO2 and TiOSO4 to chitosan structure by pyrolysis at 600 °C. Detailed characte
J. Braz. Chem. Soc.. Publicado em: 2020-06
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16. Chemically Reduced Graphene Oxide on Gold Electrodes from Recordable CDs: Characterization and Potential Sensing Applications
This work presents the development and characterization of a new chemically modified electrode exploiting recordable Au-rewritable compact discs (AuCDs) as substrate for drop casting of a chemically-reduced graphene-oxide slurry focusing on simple and low-cost electrochemical sensors. Increase in electrochemical responses in cyclic voltammetric and amperomet
J. Braz. Chem. Soc.. Publicado em: 2020-03
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17. GRAPHENE OXIDE AND A GO/ZnO NANOCOMPOSITE AS CATALYSTS FOR EPOXY RING-OPENING OF EPOXIDIZED SOYBEAN FATTY ACIDS METHYL ESTERS
Abstract In this work, the grapheme oxide (GO) and GO/ZnO nanocomposite were successfully obtained from the oxidation of graphite and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). In the GO/ZnO nanocomposite, the GO sheets were coated with aggregated
Braz. J. Chem. Eng.. Publicado em: 09/12/2019
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18. Aplicação do Formalismo CTP em uma Ação com Operador Pseudo-Diferencial
Resumo O formalismo CTP (closed-time-path) é uma ferramenta matemática para calcular funções de Green em sistemas físicos. A principal vantagem desta técnica é a de que, ao contrário do formalismo de Feynman, o formalismo CTP pode ser aplicado em sistemas fora do equilíbrio. Por outro lado, em física da matéria condensada, alguns modelos não loca
Rev. Bras. Ensino Fís.. Publicado em: 25/11/2019
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19. Smart Graphene-Based Frequency Selective Surface Designed to Act as Single or Dual Band Device with Reconfigurable Operation Bands
Abstract In this paper, a finite-difference time-domain (FDTD) formulation, based on the exponential matrix and on thin material sheet methods is developed for modeling subcellular thin graphene sheets. This formulation is validated by reproducing graphene frequency selective surfaces (FSS) known from literature. Then, we propose in this work a smart graphen
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 11/11/2019
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20. Surface Silanization of Graphene Oxide Under Mild Reaction Conditions
The functionalization of graphene oxide with organosilanes is an important strategy to yield graphene-silica composites as well as to create nanomaterials for use as reinforcement in polymer nanocomposites and corrosion-inhibiting coatings for metals, among other uses. However, depending on the reaction conditions used, the organosilanes tend to self-condens
J. Braz. Chem. Soc.. Publicado em: 24/10/2019
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21. Construction and Evaluation of a Graphene Oxide Functionalized Aminopropyltriethoxy Silane Surface Molecularly Imprinted Polymer Potentiometric Sensor for Dipyridamole Detection in Urine and Pharmaceutical Samples
A dipyridamole (DIP) based surface molecularly imprinted polymer (MIP) was synthesized and applied as a sensing agent in a sensing layer of a new modified potentiometric carbon paste electrode (CPE). The potentiometric modified CPEs (GO@SiO2-NH2-MIP/MWCNTs/CPE, where GO is graphene oxide and MWCNTs is multi-walled carbon nanotubes) showed an improved perform
J. Braz. Chem. Soc.. Publicado em: 16/09/2019
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22. Square-Wave Voltammetry Determination of Ciprofloxacin in Pharmaceutical Formulations and Milk Using a Reduced Graphene Oxide Sensor
In this paper, a simple, sensitive and precise electroanalytical method was developed using a chemically-reduced graphene-oxide (CRGO)-modified glassy carbon electrode and square wave voltammetry (SWV) for determination of ciprofloxacin in pharmaceutical formulations (tablets) and milk samples. Advantages of this sensor include a potential displacement of 10
J. Braz. Chem. Soc.. Publicado em: 16/09/2019
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23. Influence of graphene oxide on ‘in situ’ preparation of nanocomposites with polyvinyl butyral
ABSTRACT In this work, polyvinyl butyral (PVB) nanocomposites reinforced with 0.5 to 2.5 wt% of graphene oxide (GO) were synthesized via ‘in situ’ polymerization. PVB was obtained by condensation of hydroxyl groups of polyvinyl alcohol (PVA) with butyraldehyde (BU) Thermogravimetric analyzes (TGA) showed the increase in the thermal conductivity of the na
Matéria (Rio J.). Publicado em: 16/09/2019
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24. MAGNETOMETRIA IN-SITU PARA CARACTERIZAÇÃO DE MATERIAIS ELETRODEPOSITADOS
We have recently made studies of electrodeposits of Co onto graphene attached to different substrates, successfully performed via in-situ magnetization measurements. The magnetic analysis of deposits as a function of time lapse, indicate that Co grows with different magnetic characteristics from the beginning to the end of each run, independent of the substr
Quím. Nova. Publicado em: 18/07/2019