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排序方式: 共有9028条查询结果,搜索用时 31 毫秒
1.
Bazarra Noelia Castejón Alberto Fernández José R. Quintanilla Ramón 《Meccanica》2021,56(12):3025-3037
Meccanica - In this work we study, from the numerical point of view, a one-dimensional thermoelastic problem where the thermal law is of type III. Quasi-static microvoids are also assumed within... 相似文献
2.
José Alejandro Arminio-Ravelo Anders W. Jensen Dr. Kim D. Jensen Dr. Jonathan Quinson Prof. Dr. María Escudero-Escribano 《Chemphyschem》2019,20(22):2956-2963
Proton exchange membrane water electrolysers are very promising renewable energy conversion devices that produce hydrogen from sustainable feedstocks. These devices are mainly limited by the sluggish kinetics of the oxygen evolution reaction (OER). Ir-based nanoparticles are both reasonably active and stable for the OER in acidic media. The electrolyte composition and the pH may play a crucial role in electrocatalysis, yet they have been widely overlooked for the OER. Herein, we present a study on the effects of the composition and concentration of the electrolyte on commercial Ir black nanoparticles using concentrations of 0.05 M, 0.1 M and 0.5 M of both sulphuric and perchloric acid. The results show an important effect of the electrolyte composition on the catalytic performance of the Ir nanoparticles. The concentration of H2SO4 interferes on the oxidation of Ir and decreases the catalytic performance of the catalyst. HClO4 does not show strong interferences in the electrochemistry of Ir. Higher catalytic performances are observed in HClO4 electrolytes in comparison to H2SO4 with little effect of the concentration of HClO4. 相似文献
3.
Application of TiO2-nanotubes/PbO2 as an anode for the electrochemical elimination of Acid Red 1 dye
Santos José Eudes L. de Moura Dayanne Chianca da Silva Djalma Ribeiro Panizza Marco Martínez-Huitle Carlos A. 《Journal of Solid State Electrochemistry》2019,23(2):351-360
Journal of Solid State Electrochemistry - In this study, galvanostatic electrolysis, through the use of the platinum supported on Ti (Ti/Pt) and Ti/TiO2-nanotubes/PbO2 anodes, was conducted in an... 相似文献
4.
José E. Barquera-Lozada 《Journal of computational chemistry》2019,40(30):2602-2610
The induced current density ( J ( r )) provides useful information about the electronic structure of molecules under a magnetic field ( B ). However, the analysis of its topology is cumbersome because of its vectorial nature. We show that its tropicity (direction of rotation) and its strength can be compressed in the triple product B ⋅ ∇ × J ( r ) (tp J ( r )) that is a scalar field. The topology of tp J ( r ) has clear similarities to the Laplacian of the electron density. Additionally, the topology of aromatic and antiaromatic compounds is notoriously different. The vorticity of J ( r ) is helpful to define the circulation of the current density, C, that contrary to other methods, can be easily defined for individual rings in polycyclic molecules. This allows tp J ( r ) to clearly reproduce the Clar's structure of polycyclic aromatic hydrocarbons. © 2019 Wiley Periodicals, Inc. 相似文献
5.
Jaume Llibre Ricardo Miranda Martins Durval José Tonon 《Journal of Dynamics and Differential Equations》2018,30(3):1011-1027
In this paper we study the limit cycles of some classes of piecewise smooth vector fields defined in the two dimensional torus. The piecewise smooth vector fields that we consider are composed by linear, Ricatti with constant coefficients and perturbations of these one, which are given in (3). Considering these piecewise smooth vector fields we characterize the global dynamics, studying the upper bound of number of limit cycles, the existence of non-trivial recurrence and a continuum of periodic orbits. We also present a family of piecewise smooth vector fields that posses a finite number of fold points and, for this family we prove that for any 2k number of limit cycles there exists a piecewise smooth vector fields in this family that presents k number of limit cycles and prove that some classes of piecewise smooth vector fields presents a non-trivial recurrence or a continuum of periodic orbits. 相似文献
6.
Trujillo Cristina Sánchez-Sanz Goar Elguero José Alkorta Ibon 《Structural chemistry》2020,31(5):1909-1918
Chloride complexes of gold(I) (seventeen) and gold(III) (seventeen) with different ligands (including H, C, N, O, P, S as interacting atoms) have been studied at the CCSD(T)/CBS level. The computed geometries were compared with those found in the Cambridge Structural Database and the dissociation energies related with those previously reported in the literature by Yamamoto et al. Some special processes catalysed by these gold complexes such as bond-breaking (dihydrogen, cyclopropane) and arenes reactivity were studied in detail.
相似文献7.
Brandão Pedro Francisco Ramos Rui Miguel Rodrigues José António 《Analytical and bioanalytical chemistry》2018,410(26):6873-6880
Analytical and Bioanalytical Chemistry - Formaldehyde is often applied in the industrial production of different products, such as textiles, insulation materials, or cosmetics, due to its... 相似文献
8.
Carbon Dots (C‐dots) from Cow Manure with Impressive Subcellular Selectivity Tuned by Simple Chemical Modification 下载免费PDF全文
Cintya D'Angelis do E. S. Barbosa Dr. José R. Corrêa Gisele A. Medeiros Gabrielle Barreto Dr. Kelly G. Magalhães Dr. Aline L. de Oliveira Prof. Dr. John Spencer Prof. Dr. Marcelo O. Rodrigues Prof. Dr. Brenno A. D. Neto 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(13):5055-5060
Improved cellular selectivity for nucleoli staining was achieved by simple chemical modification of carbon dots (C‐dots) synthesized from waste carbon sources such as cow manure (or from glucose). The C‐dots were characterized and functionalized (amine‐passivated) with ethylenediamine, affording amide bonds that resulted in bright green fluorescence. The new modified C‐dots were successfully applied as selective live‐cell fluorescence imaging probes with impressive subcellular selectivity and the ability to selectively stain nucleoli in breast cancer cell lineages (MCF‐7). The C‐dots were also tested in four other cellular models and showed the same cellular selection in live‐cell imaging experiments. 相似文献
9.
Beatriz Pelado Dr. Fawzi Abou‐Chahine Joaquín Calbo Dr. Rubén Caballero Dr. Pilar de la Cruz Dr. José M. Junquera‐Hernández Prof. Enrique Ortí Prof. Nikolai V. Tkachenko Prof. Fernando Langa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5814-5825
The role of π‐conjugated molecular bridges in through‐space and through‐bond electron transfer is studied by comparing two porphyrin–fullerene donor–acceptor (D–A) dyads. One dyad, ZnP–Ph–C60 (ZnP=zinc porphyrin), incorporates a phenyl bridge between D and A and behaves very similarly to analogous dyads studied previously. The second dyad, ZnP–EDOTV–C60, introduces an additional 3,4‐ethylenedioxythienylvinylene (EDOTV) unit into the conjugated bridge, which increases the distance between D and A, but, at the same time, provides increased electronic communication between them. Two essential outcomes that result from the introduction of the EDOTV unit in the bridge are as follows: 1) faster charge recombination, which indicates enhanced electronic coupling between the charge‐separated and ground electronic states; and 2) the disappearance of the intramolecular exciplex, which mediates photoinduced charge separation in the ZnP–Ph–C60 dyad. The latter can be interpreted as a gradual decrease in electronic coupling between locally excited singlet states of D and A when introducing the EDOTV unit into the D–A bridge. 相似文献
10.
New di‐ and triorganotin(IV) carboxylates derived from a Schiff base: synthesis,characterization and in vitro antimicrobial activities 下载免费PDF全文
Letícia C. Dias Geraldo M. de Lima Jacqueline A. Takahashi José D. Ardisson 《应用有机金属化学》2015,29(5):305-313
A new carboxylic acid, 2‐{[5‐(2‐nitrophenyl)furan‐2‐yl]methyleneamino}benzoic acid (HOBZ), has been produced by reacting 5‐(2‐nitrophenyl)furfural with 2‐aminobenzoic acid. Reactions of NaOBZ with organotin chlorides led to formation of [Me3Sn(OBZ)] ( 1 ), [Bu3Sn(OBZ)] ( 2 ), [Me2Sn(OBZ)2] ( 3 ) and [Bu2Sn(OBZ)2] ( 4 ). Complexes 1 , 2 , 3 , 4 have been characterized using elemental analyses and infrared, 1H NMR, 13C NMR, 119Sn NMR and 119Sn Mössbauer spectroscopies. In the solid state, the OBZ ligands might coordinate to tin in an anisobidentate fashion via the carboxylate group. The in vitro antimicrobial activity of all compounds has been screened against the following fungi: Aspergillus niger, A. flavus, A. parasiticus, Penicillium citrinum, Candida dubliniensis, C. lusitaniae, C. albicans, C. tropicalis, C. parapsilosis and C. glabrata; and against the following bacteria: Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Streptococcus sanguinis, Escherichia coli, Citrobacter frendii, Salmonella typhimurium and Pseudomonas aeruginosa. Complexes 2 and 4 exhibited higher biocide activity in comparison to 1 and 3 and to the control drugs nystatin and miconazole nitrate for the yeasts, and chloramphenicol and ampicillin for the bacteria. The biological activity of 2 was superior to that of 4 . In addition, the toxicity of HOBZ, NaOBz and 1 , 2 , 3 , 4 were determined using Chlorella vulgaris, revealing low toxicity of the complexes at MIC50 concentrations. We also performed cell viability studies, using XTT assay, displaying no change in the mitochondrial function after 2–4 h of exposure of the microorganism to the complexes at MIC50 concentrations. The butyl‐containing complexes 2 and 4 display greater lipophilicities than do the methyl analogues 1 and 3 , thereby endowing 2 and 4 with superior abilities to cross the microbe cell membrane, the possible mechanism of action. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献