Applications Techniques
Mostrando 1-12 de 820 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. Influence of the addition of niobium oxide on the properties of fused aluminum oxide used in abrasive tools
Abstract Fused alumina is a material used in the manufacturing of abrasive tools, due to its high fusion point, great hardness, and mechanical toughness. In this context, this study addressed the influence of niobium addition on the properties of fused alumina for abrasive applications. A comparison was also made between this oxide and the brown fused alumin
Cerâmica. Publicado em: 2022
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3. The influence of separately and combined bentonite and kaolinite as binders for pelletization of NaA zeolite from coal fly ash
Abstract Pelletization of zeolitic materials is required to facilitate their practical industrial and commercial applications. Zeolite-NaA was synthesized from fly ash by the fusion method and shaped into spherical granules. Bentonite, kaolinite, and a combination of bentonite with kaolinite were tested as binders with different contents from 5 to 10 wt%. Th
Cerâmica. Publicado em: 2022
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4. Assessment of Total Attenuation and Adaptive Scheme for Quality of Service Enhancement in Tropical Weather for Satellite Networks and 5G Applications in Nigeria
Abstract The dynamic weather condition is a major concern for optimum channel utilization in recent times, especially at higher frequencies with larger bandwidth for 5G applications. Over the years, rain-induced attenuation among the hydrometeors has been linked as the major cause of signal impairment especially at the frequency, f ≥ 10 GHz. However, when
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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5. Acid matrix production from treated natural vermiculite-hydrobiotite
Abstract Given the potential of acid-activated clays in adsorptive and catalytic processes, several studies focusing on acid matrices have grown over the years, making it possible to study vermiculite, a mineral composed of a type 2:1 unit cell with tetrahedral and octahedral sheets. Therefore, this work aimed to study vermiculite treated with acids for the
Cerâmica. Publicado em: 2021-06
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6. Metamaterial-Fractal-Defected Ground Structure Concepts Combining for Highly Miniaturized Triple-Band Antenna Design
Abstract In this paper, a novel method is proposed to increase the gain and radiation efficiency of a compact patch antenna. By employing a combination of three efficient techniques, we have developed a multi-resonance L-DGS antenna with a high gain of 5 dB and an efficiency of 99.6%. Furthermore, a novel compact Double Negative metamaterial unit cell and it
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-12
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7. 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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8. Metabolomics as a potential tool for the diagnosis of growth hormone deficiency (GHD): a review
ABSTRACT Metabolomics uses several analytical tools to identify the chemical diversity of metabolites present in organisms. These metabolites are low molecular weight molecules (<1500 Da) classified as a final or intermediary product of metabolic processes. The application of this omics technology has become prominent in inferring physiological conditions th
Arch. Endocrinol. Metab.. Publicado em: 2020-12
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9. A Symmetrical Dirhenium(I) Complex with 4,4’’-Azobis(2,2’-bipyridine) as a Bridging Ligand: Synthesis, Physicochemical Properties and Applications in Detection of Biologically Relevant Thiols and in Chemotherapy for Bone Cancer
A new dinuclear complex of formula [{Re(CO)3(py)}2(µ-4,4”-azobpy)](PF6)2, with py = pyridine and 4,4”-azobpy = 4,4”-azobis(2,2’-bipyridine), has been synthesized and characterized by spectroscopic and electrochemical techniques. The symmetrical nature of the dimetallic cation has been confirmed by nuclear magnetic resonance (NMR) measurements. When
J. Braz. Chem. Soc.. Publicado em: 2020-11
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10. A Calix[4]arene-Functionalized Perylene Imide and Its Luminescence Properties
In this study, new perylene-derived molecules were synthesized as perylene-3,4,9,10-tetracarboxylic acid monoanhydride monopotassium carboxylate 1; N-(3-propanol)perylene-3,4,9,10-tetracarboxylic-3,4-(monoimide)anhydride-9,10-acid potassium carboxylate 2; 5,11,17,23-tetra(tert-butyl)-25,27-bis(3’-bromopropoxy)-26,28-(dihydroxy)calix[4]arene 3; 5,11,17,23-t
J. Braz. Chem. Soc.. Publicado em: 2020-11
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11. TÉCNICAS AVANÇADAS PARA A DIFERENCIAÇÃO DE ISÔMEROS POR ESPECTROMETRIA DE MASSAS
Mass spectrometry (MS) is a powerful and widespread technique but is inherently uncapable to differentiate species with same m/z ratio. For this reason, many classical approaches were developed based on differential fragmentation patterns in tandem MS. More recently, new techniques for isomer identification in MS were developed, and we highlight the photodis
Quím. Nova. Publicado em: 2020-09
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12. AVALIAÇÃO DE NANOTUBOS DE CARBONO FUNCIONALIZADOS VISANDO O DESENVOLVIMENTO DE MÉTODOS DE PRÉ-CONCENTRAÇÃO DE ÍONS METÁLICOS E DETERMINAÇÃO POR TÉCNICAS ESPECTROMÉTRICAS E ELETROANALÍTICAS
This review focuses on the use of functionalized carbon nanotubes (CNTs) on the development of preconcentration methods with substantial contributions on selectivity and sensitivity for metal ions determination. CNTs have been usually employed in the development of preconcentration/speciation coupled to spectroanalytical techniques for ions determination at
Quím. Nova. Publicado em: 2020-09