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81.
Tin oxalate as a precursor of tin dioxide and electrode materials for lithium-ion batteries 总被引:2,自引:0,他引:2
R. Alcántara Fernández F. Madrigal P. Lavela C. Pérez-Vicente J. Tirado 《Journal of Solid State Electrochemistry》2001,6(1):55-62
Tin(II) oxalate was studied as a novel precursor for active electrode materials in lithium-ion batteries. The discharge of
lithium cells using tin oxalate electrodes takes place by three irreversible steps: tin reduction, forming a lithium oxalate
matrix; solvent decomposition to form a passivating layer; and oxalate reduction in a two-electron process. These are followed
by reversible alloying of tin with lithium, leading to a maximum discharge of 11 F/mol. Cycling of the cells showed reversible
capacities higher than 600 mAh/g during the first five cycles and ca. 200 mAh/g after 50 cycles. Tin oxalate was converted
to tin dioxide by thermal decomposition at 450 °C and also by a chemical method by dissolving tin oxalate powder in 33% v/v
hydrogen peroxide at room temperature. The ultrafine nature of the tin dioxide powders obtained by this procedure allow their
use as electrodes in lithium cells. The best capacity retention during the first five cycles was achieved for a sample heat
treated to 250 °C to eliminate surface water.
Electronic Publication 相似文献
82.
Helio G. Bonacorso Francieli M. Libero Fábio M. Luz Maiara C. Moraes Susiane Cavinatto Felipe S. Stefanello Melissa B. Rodrigues Nilo Zanatta Marcos A.P. Martins 《Tetrahedron letters》2017,58(40):3827-3830
This work reports the synthesis of a series of (1H-1,2,3-triazol-4-yl)carbohydrazides (2), which were obtained from 4-trichloroacetyl-1H-1,2,3-triazoles (1). Triazoles 1 were synthesized by 1,3-dipolar cycloaddition reaction, starting from 4-alkoxy-1,1,1-trichloroalk-3-en-2-ones and benzyl azides and easily (15 min) converted to 2 by reaction with hydrazine hydrate (73–82% yield). Carbohydrazides 2 proved to be a versatile building block for constructing a series of fluorinated heterocycles analogous to rufinamide, i.e., 1H-1,2,3-triazol-4-yl-1,3,4-oxadiazoles, a pyrrole derivative, and a 2-pyrazoline, through [4+1]–, [1+4]–, and [3+2]–cyclocondensation reactions, respectively. Finally, and according to the Lipinski’s rule of five, 2,6-difluorobenzylated 1,2,3-triazoles can be considered as potential candidates for further biological activity assays. 相似文献
83.
Effectiveness of Photodynamic Therapy in Elimination of HPV‐16 and HPV‐18 Associated with CIN I in Mexican Women 下载免费PDF全文
Elizabeth Maldonado Alvarado Martha Olivia Osorio Peralta Alejandra Moreno Vázquez Lydia Alejandra Martínez Guzmán Maria Eugenia Melo Petrone Zulma Iveth Enriquez Mar Dora Estela Jovel Galdamez Bárbara Carrión Solana Guadalupe Balderas Martínez Eduarda Parra Rossana Inés Castellanos Oliveros Rosa Linda Bello Leiva Araceli Espinosa Montesinos Citlalli Barrera Mendoza Selma Eugenia Medina García Eva Ramón Gallegos 《Photochemistry and photobiology》2017,93(5):1269-1275
This study aimed to determine the effectiveness of photodynamic therapy (PDT), using δ‐aminolevulinic acid (5‐ALA), in the elimination of premalignant cervical lesions in Mexican patients with human papillomavirus (HPV) infection and/or cervical intraepithelial neoplasia (CIN). Thirty women diagnosed with CIN I and/or positive for HPV participated in the study. Topical 6% 5‐ALA in gel form was applied to the uterine cervix; after 4 h, the lesion area was irradiated with a light dose of 200 J cm?2 at 635 nm. This procedure was performed three times at 48‐h intervals. Clinical follow‐up was performed at 3, 6, and 12 months after the initial PDT administration, by colposcopy, cervical cytology, histopathological analysis, polymerase chain reaction, and hybrid capture. Of HPV‐infected patients without evidence of CIN I, 80% cleared the infection, while HPV associated with CIN I was eliminated in 83% of patients (P < 0.05). At 12 months, CIN I had regressed in 57% of patients, although this response was not statistically significant. PDT using 6% 5‐ALA is concluded to be effective in eliminating HPV infection associated or not with CIN I. 相似文献
84.
The synthesis and properties of the ion exchange polymer 3‐n‐propyl(3‐methylpyridinium)silsesquioxane chloride (SiPy+Cl?) are described. Based on the Langmuir model, the equilibrium constant at the solid‐solution interface for the reaction, SiPy+Cl?+NO ?SiPy+NO , was calculated for nitrite adsorption. The value found, β=8.7×103 L mol?1, indicates good affinity of the anion for the solid phase. A carbon paste electrode of the material was tested for NO oxidation and a linear response, in the concentration range between 6.3 and 143.6 μmol L?1, was obtained by amperometry. The analytical applicability of the proposed system was ascertained by the satisfactory results attained in its application to monitoring of nitrite in natural waters. 相似文献
85.
Flavio S. Damos Rita C.S. Luz Auro A. Tanaka Lauro T. Kubota 《Analytica chimica acta》2010,664(2):144-10063
The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using the host-guest binding of a supramolecular complex at a host surface by combining a self-assembled monolayer (SAM) of mono-(6-deoxy-6-mercapto)-β-cyclodextrin (βCDSH), iron (III) tetra-(N-methyl-4-pyridyl)-porphyrin (FeTMPyP) and cyclodextrin-functionalized gold nanoparticles (CDAuNP). The supramolecular modified electrode showed excellent catalytic activity for oxygen reduction. The reduction potential of oxygen was shifted about 200 mV toward less negative values with this modified electrode, presenting a peak current much higher than those observed on a bare gold electrode. Cyclic voltammetry and rotating disk electrode (RDE) experiments indicated that the oxygen reduction reaction involves probably 4-electrons with a rate constant (kobs) of 7 × 104 mol−1 L s−1. A linear response range from 0.2 up to 6.5 mg L−1, with a sensitivity of 5.5 μA L mg−1 (or 77.5 μA cm−2 L mg−1) and a detection limit of 0.02 mg L−1 was obtained with this sensor. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation was 3.0% for 10 measurements of a solution of 6.5 mg L−1 oxygen. 相似文献
86.
Juliana S Luz Celso RR Ramos Márcia CT Santos Patricia P Coltri Fernando L Palhano Debora Foguel Nilson IT Zanchin Carla C Oliveira 《BMC biochemistry》2010,11(1):22
Background
The archaeal exosome is formed by a hexameric RNase PH ring and three RNA binding subunits and has been shown to bind and degrade RNA in vitro. Despite extensive studies on the eukaryotic exosome and on the proteins interacting with this complex, little information is yet available on the identification and function of archaeal exosome regulatory factors. 相似文献87.
Mata S Cortijo V Caminati W Alonso JL Sanz ME López JC Blanco S 《The journal of physical chemistry. A》2010,114(43):11393-11398
The Fourier transform microwave spectra of the hydrated forms of the tautomeric pair 2-pyridinone/2-hydroxypyridine (2PO/2HP) have been investigated in a supersonic expansion. Three hydrated species, 2PO-H?O, 2HP-H?O, and 2PO-(H?O)?, have been observed in the rotational spectrum. Each molecular complex was confidently identified by the features of the 1?N quadrupole hyperfine structure of the rotational transitions. The presence of water affects the tautomeric equilibrium -N═C(OH)- ? -NH-C(═O)-, which is shifted to the enol form for the bare molecules 2PO/2HP but to the keto tautomer for the hydrated forms. 相似文献
88.
Arik M Aune S Barth K Belov A Borghi S Bräuninger H Cantatore G Carmona JM Cetin SA Collar JI Dafni T Davenport M Eleftheriadis C Elias N Ezer C Fanourakis G Ferrer-Ribas E Friedrich P Galán J García JA Gardikiotis A Gazis EN Geralis T Giomataris I Gninenko S Gómez H Gruber E Guthörl T Hartmann R Haug F Hasinoff MD Hoffmann DH Iguaz FJ Irastorza IG Jacoby J Jakovčić K Karuza M Königsmann K Kotthaus R Krčmar M Kuster M Lakić B Laurent JM Liolios A Ljubičić A Lozza V Lutz G Luzón G Morales J 《Physical review letters》2011,107(26):261302
The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using (3)He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with (4)He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV?m(a)?0.64 eV. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g(aγ)?2.3×10(-10) GeV(-1) at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m(a)?1.15 eV, comfortably overlapping with cosmological hot dark matter bounds. 相似文献
89.
This paper addresses two different but related questions regarding an unbounded symmetric tridiagonal operator: its self-adjointness and the approximation of its spectrum by the eigenvalues of its finite truncations. The sufficient conditions given in both cases improve and generalize previously known results. It turns out that, not only self-adjointness helps to study limit points of eigenvalues of truncated operators, but the analysis of such limit points is a key help to prove self-adjointness. Several examples show the advantages of these new results compared with previous ones. Besides, an application to the theory of continued fractions is pointed out. 相似文献
90.
Farid Ammar Khodja Assia Benabdallah Manuel González-Burgos Luz de Teresa 《Comptes Rendus Mathematique》2014,352(5):391-396
We consider two parabolic equations coupled by a matrix A(x)=q(x)A0, where A0 is a Jordan block of order 1, and controlled by a single localized function, or by a single boundary control. The support of the coupling coefficient, q , and the control domain may be disjoint. We exhibit an explicit minimal time of null-controllability, T0(q)∈[0,+∞]. 相似文献