Core Shell
Mostrando 1-12 de 175 artigos, teses e dissertações.
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1. Atomic Absorption Spectrometry as an Alternative to Determine the Presence of Gold Nanoparticles on or in Silica Matrix
Two different gold-silica-based nanomaterials were prepared: (i) silica-supported gold nanoparticles (AuNP/SiO2); and (ii) gold-silica core-shell nanoparticles (AuNP@SiO2). Three strategies for sample treatment (S), consisting in acid treatments, were employed: (S1) HNO3; (S2) HNO3 + HCl; and (S3) HF + HNO3 + HCl, applying microwave oven digestion for S2 and
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Synthesis, Characterization and Photocatalytic Activity of Au/SiO2@TiO2 Core-Shell Microspheres
By using HAuCl4 as the gold precursor, spherical Au@SiO2/TiO2 core-shell nanostructures were prepared with the sol-gel method and ethanol reflux. The preparation process was convenient and fast. The obtained samples were characterized by UV-Vis, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TE
J. Braz. Chem. Soc.. Publicado em: 2020-03
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3. Obtaining of Fe3O4@C Core-Shell Nanoparticles as an Adsorbent of Tetracycline in Aqueous Solutions
Tetracycline is used to treat various diseases in animals and humans, so its high use causes this substance to be frequently found in effluents and in potable water reservoirs, causing serious problems for human health and the environment. Many processes are applied and evaluated in an attempt to removal tetracycline found in environment, such as adsorption.
Mat. Res.. Publicado em: 30/09/2019
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4. Fe3O4@C core-shell nanoparticles as adsorbent of ionic zinc: evaluating of the adsorptive capacity
Zinc is an important chemical element in many metabolic mechanisms at low concentrations, but can be toxic when administrated in doses higher than 500 µg·g-1 or 3 mg·L-1. This metal has been detected in many aquatic environments due to several industry activities and swine manure effluents. Thus, the contaminant removal of water and wastewater has been a
Mat. Res.. Publicado em: 01/07/2019
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5. Morphometric analysis in the shells of the planktonic foraminifera Orbulina universa: a source for paleoceanographic information?
Abstract In this study, we describe morphometric analyses of Orbulina universa morphotypes presently found in the Western South Atlantic, and their relation to the upper water thermohaline indexes. We also investigate this relationship under glacial and interglacial conditions between 7.2 and 32 kyr BP. Ten plankton samples distributed between 32º55' and 26
Braz. j. oceanogr.. Publicado em: 27/05/2019
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6. Fe3O4-TiO2 and Fe3O4-SiO2 Core-shell Powders Synthesized from Industrially Processed Magnetite (Fe3O4) Microparticles
The interest for core-shells has been increased in the recent years due to their improved and modifiable properties. In this work, Fe3O4-TiO2 and Fe3O4-SiO2 core-shells were successfully synthesized from an industrially produced magnetite-rich powder with micro- and nanometric particle sizes, superparamagnetic behavior and saturation magnetization of 49 emu/
Mat. Res.. Publicado em: 09/05/2019
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7. New Synthesis Method for a Core-Shell Composite Based on α-Bi2O3 @PPy and its Electrochemical Behavior as Supercapacitor Electrode
New composite based on polypyrrole (PPy) and bismuth oxide (α-Bi2O3) was investigated as supercapacitor electrode. The α-Bi2O3 was obtained by hydrothermal route at 500 ºC for 2 h. Cyclic voltammetry was used to electropolymerize PPy on graphite electrode (GE) or on GE/α-Bi2O3. The X-ray diffraction profile of Bi2O3 revealed the α-Bi2O3 monoclinic struc
J. Braz. Chem. Soc.. Publicado em: 2019-04
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8. Estudio Ab-initio de propiedades estructurales, elásticas y electrónicas de nanohilos core/shell
ABSTRACT This Zinc oxide (ZnO) is widely used in different electronic devices due to its thermal, electronic, and piro-piezoelectric properties. Some of these properties are noticeable improvement at the nanoscale, specially when ZnO together with other material create heterostructures. Recently, core/shell nanowires have been synthesized in order to raise t
Matéria (Rio J.). Publicado em: 19/07/2018
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9. Physiochemical and Optical Properties of GdF3:Pr@LaF3@SiO2 Microspheres
The polyol-based co-precipitation process was employed for synthesis of GdF3:Pr (core) and GdF3:Pr@LaF3 (core-shell) microspheres (MSs). Subsequently, an amorphous silica layer was deposited surrounding the core-shell MSs, which was verified from high-resolution transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) and FTIR results.
Mat. Res.. Publicado em: 12/04/2018
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10. A Novel Electrochemical Aptamer Biosensor Based on DNAzyme Decorated Au@Ag Core-Shell Nanoparticles for Hg2+ Determination
As a kind of important water pollutant, heavy metal ions have a detrimental effect on the health of human. In this study, Au@Ag core-shell nanoparticles were synthesized by simple reduction of Ag + around Au nanoparticles and functionalized by DNAzyme. Based on thymine-Hg2+-thymine binding mode, a sensitive aptamer biosensor was constructed by utilizing func
J. Braz. Chem. Soc.. Publicado em: 2018-02
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11. Preparation and Performance of an Estradiol Templated Magnetic Sphere of Molecularly Imprinted Cryogel
An estradiol templated core-shell magnetic molecularly imprinted cryogel (MMIC) was synthesized to selectively extract and analyze estradiol in milk powder. The microsphere of Fe3O4@SiO2 was firstly prepared on Fe3O4 with ethyl silicate and 3-methyl propyl trimethoxy silane. Then the polymerization of α-methacrylic acid and ethylene glycol dimethyl acrylate
J. Braz. Chem. Soc.. Publicado em: 2018-01
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12. Surface Charge Density Determination in Water Based Magnetic Colloids: a Comparative Study
This work focuses on the systematic investigation of the two well-established methods of structural surface charge density determination on magnetic colloids, labeled as Single Potentiometric Method (SPM) and Potentiometric-Conductometric Method (PCM). To compare some important features of the methods we determined the structural surface charge density of ma
Mat. Res.. Publicado em: 09/10/2017