排序方式: 共有26条查询结果,搜索用时 15 毫秒
1.
de Araújo Moisés A. Lucas Francisco W. S. Mascaro Lucia H. 《Journal of Solid State Electrochemistry》2020,24(2):389-399
Journal of Solid State Electrochemistry - The present work outlines a simple and novel approach to obtain nanostructured and heterostructured SnS/Sb2S3 thin films. This material showed enhanced... 相似文献
2.
Fernando Cruz Moraes Sonia Tomie Tanimoto Giancarlo Richard Salazar‐Banda Sergio Antonio Spinola Machado Lucia Helena Mascaro 《Electroanalysis》2009,21(9):1091-1098
The electrochemical detection of the hazardous pollutant 4‐nitrophenol (4‐NP) at low potentials, in order to avoid matrix interferences, is an important research challenge. This study describes the development, electrochemical characterization and utilization of a multiwall carbon nanotube (MWCNT) film electrode for the quantitative determination of 4‐NP in natural water. Electrochemical impedance spectroscopy measurements showed that the modified surface exhibits a decrease of ca. 13 times in the charge transfer resistance when compared with a bare glassy carbon (GC) surface. Voltammetric experiments showed the possibility to oxidize a hydroxylamine layer (produced by the electrochemical reduction of 4‐NP on the GC/MWNCT surface) in a potential region which is approximately 700 mV less positive than that needed to oxidize 4‐NP, thus minimizing the interference of matrix components. The limit of detection for 4‐NP obtained using square‐wave voltammetry (0.12 μmol L?1) was lower than the value advised by EPA. A natural water sample from a dam located in São Carlos (Brazil) was spiked with 4‐NP and analyzed by the standard addition method using the GC/MWCNT electrode, without any further purification step. The recovery procedure yielded a value of 96.5% for such sample, thus confirming the suitability of the developed method to determine 4‐NP in natural water samples. The electrochemical determination was compared with that obtained by HPLC with UV‐vis detection. 相似文献
3.
Fernando C. Moraes Lucia H. Mascaro Sergio A. S. Machado Christopher M. A. Brett 《Electroanalysis》2010,22(14):1586-1591
A copper phthalocyanine/multiwalled carbon nanotube film‐modified glassy carbon electrode has been used for the determination of the herbicide glyphosate (Gly) at ?50 mV vs. SCE by electrochemical oxidation using differential pulse voltammetry (DPV). Cyclic voltammetry and electrochemical impedance spectroscopy showed that Gly is adsorbed on the metallic centre of the copper phthalocyanine molecule, with formation of Gly‐copper ion complexes. An analytical method was developed using DPV in pH 7.4 phosphate buffer solution, without any pretreatment steps: Gly was determined in the concentration range of 0.83–9.90 μmol L?1, with detection limit 12.2 nmol L?1 (2.02 μg L?1). 相似文献
4.
Djenaine De Souza Lucia Helena Mascaro Orlando Fatibello-Filho 《Journal of Solid State Electrochemistry》2011,15(9):2023-2029
The main purpose of this work was to evaluate the effect of the silver to mercury ratio on the voltammetric responses of silver
solid amalgam electrodes (AgSAE’s). For this, the AgSAE were prepared by mechanical mixing the metals in the following mass
ratios of silver to mercury: 30/70, 40/60, 50/50, 60/40, and 70/30. The resulting AgSAE’s were physically characterized by
energy dispersive X-ray analysis, X-ray diffraction and scanning electron microscopy, confirming the mass percentages of the
silver and mercury, the total absence of liquid mercury and a globular structure of all AgSAE’s. Furthermore, it was observed
that the AgSAE 30/70 contained only one single phase (Ag2Hg3), and no metallic silver or mercury oxides. Additionally, the resulting AgSAE’s were chemically characterized with respect
to the influence of the electrode composition on the reproducibility and electrochemical signals of a hexamine-ruthenium (III)
chloride solution by use of electrochemical impedance spectroscopy and cyclic voltammetry. The separation between anodic and
cathodic peaks, and consequently, the charge transfer resistance across the electrode/solution interface, and the electroactive
area were calculated demonstrating that the 30/70 composition is the best surface for practical applications. Finally, square-wave
voltammetry experiments were performed in 4-nitrophenol solution, with a previous optimization of the experimental and voltammetric
parameters. The calculated detection limit shows that the AgSAE 30/70 is suitable for determining any contamination by p-nitrophenol, minimizing the toxic residues in case of using liquid mercury electrodes. 相似文献
5.
Bento Fábio R. Corradini Patricia G. Mascaro Lucia H. 《Journal of Solid State Electrochemistry》2019,23(6):1861-1870
Journal of Solid State Electrochemistry - A versatile and low-cost methodology for fabricating free-standing carbon graphite (CG)/SnO2/single-walled carbon nanotube (SWCNT) composites as anode... 相似文献
6.
de Araújo Moisés A. Coelho Dyovani Mascaro Lucia H. Pereira Ernesto C. 《Journal of Solid State Electrochemistry》2018,22(5):1539-1548
Journal of Solid State Electrochemistry - The water photo-oxidation to oxygen on iron oxyhydroxide (FeOOH) deposited on a surface of semiconductor materials play a crucial role in the enhancement... 相似文献
7.
F. M. Rubino P. Mascaro G. Palmisano G. Appendino G. Cravotto S. Tagliapietra G. M. Nano 《Journal of mass spectrometry : JMS》1992,27(5):597-603
A series of novel pyranocoumarin derivatives were analysed by electron impact mass spectrometry and tandem mass spectrometry at low aud high collision energy. The collision-induced decomposition tandem mass spectra of the [M ? CH3]+ ions yielded several structurally valuable fragments and those of the [M ? CH3]2+ ions allowed some charge-separation reactions to be recognized. 相似文献
8.
A. Liguori P. Mascaro B. Porcelli G. Sindona N. Uccella 《Journal of mass spectrometry : JMS》1991,26(6):608-612
Electron impact ionized purine bases such as caffeine and its metabolites (theopbylline, theobromine, paraxanthine, 1-methylxanthine, 3-metnybumthine and 7-methyIxanthine) were characterized by tandem mass spectrometry. The direct analysts of human urinary extracts by tandem mass spectrometry allows the unambiguous identification of caffeine and its metabolites present simultaneously in the urine. 相似文献
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10.
Post-buckling analysis of slender elastic vertical rods subjected to terminal forces and self-weight
This article presents the behavior of slender elastic rods subjected to axial terminal forces and self-weight. The mathematical formulation is presented, a solution is sought for a double-hinged boundary condition and the analysis is carried out for different values of non-dimensional weight. The formulation derives from geometrical compatibility, equilibrium of forces and moments and constitutive relations yielding a set of six first order non-linear ordinary differential equations with boundary conditions specified at both ends, which characterizes a complex two-point boundary value problem. Furthermore, a perturbation method is used to find the critical buckling loads and initial post-buckling solutions. A numerical integration scheme based on a three parameter shooting method is employed in the post-buckling solutions. 相似文献