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The electrochemical insertion of lithium ions into the spinel NiCo 2 O 4 prepared by thermal decomposition of carbonates and by sol-gel process has been studied. The galvanostatic discharge curves show that the best performance is... more
The electrochemical insertion of lithium ions into the spinel NiCo 2 O 4 prepared by thermal decomposition of carbonates and by sol-gel process has been studied. The galvanostatic discharge curves show that the best performance is obtained for sol-gel preparation. The oxides have been characterized by XRD, surface area, OCV and XPS measurements. The effect of preparation method on the electrochemical lithium insertion is discussed in terms of thermodynamical and kinetical properties. The preparation of spinel oxide host by sol-gel seems very promising.
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Abstract Manganese lithium oxides with spinel-related structure, LiCo0.5Mn1.5O4-δ and LiFe0.5Mn1.5O4-δ, have been synthesized for the first time using an ultrasound-assisted thermal decomposition of nitrates (UA-TDN) synthesis method. The... more
Abstract Manganese lithium oxides with spinel-related structure, LiCo0.5Mn1.5O4-δ and LiFe0.5Mn1.5O4-δ, have been synthesized for the first time using an ultrasound-assisted thermal decomposition of nitrates (UA-TDN) synthesis method. The materials were studied by X-ray powder diffraction, scanning and transmission electron microscopy, oxygen stoichiometry determinations, Raman and X-ray photoelectron spectroscopy. The Rietveld refinement of the X-ray diffraction data indicated that the samples crystallize in the Fd 3 ‾ m space group which is characteristic of the cubic spinel structure and have a cell parameter of 0.8117 nm (LiCo0.5Mn1.5O4-δ) and 0.8254 nm (LiFe0.5Mn1.5O4-δ). The Scherrer method and the Williamson-Hall (W–H) method were used to evaluate the crystallite sizes. Energy-dispersive X-ray spectroscopy analyses confirmed that the metals were present in the expected stoichiometry. Scanning and transmission electron microscopy images showed that the particles are of an irregular polyhedral shape, having average sizes of 600 and 750 nm for the Co- and Fe-containing materials, respectively. X-ray photoelectron spectroscopy measurements revealed the presence of metal cations in high oxidation states: Co3+, Fe3+, Mn3+ and Mn4+. Considering the ensemble of the results obtained, it is possible to propose the following ionic distributions L i + [ C o 0.5 3 + M n 0.6 3 + M n 0.9 4 + ] O 3.95 2 − and L i + [ F e 0.5 3 + M n 0.5 3 + M n 1.0 4 + ] O 4 2 − .
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Abstract Oxides LiNixCoyMn2-x-yO4+δ (x, y = 1/3, 1/4) were synthesized at 800 °C by sol–gel (SG) and sol–gel-assisted ultrasound (UASG) methods. The Rietveld refinement of the XRD data indicated that all the compounds crystallize in the... more
Abstract Oxides LiNixCoyMn2-x-yO4+δ (x, y = 1/3, 1/4) were synthesized at 800 °C by sol–gel (SG) and sol–gel-assisted ultrasound (UASG) methods. The Rietveld refinement of the XRD data indicated that all the compounds crystallize in the spinel structure and allowed to propose the corresponding cation distributions. SEM and TEM images showed that the oxides prepared by both methods consist of irregular polyhedra in the submicron size range. The samples prepared by UASG have both higher surface areas and Li+ ion diffusion coefficients than those synthesized by the SG method. XPS studies of these oxides reveal the presence of Ni2+, Ni3+, Co3+, Mn3+ and Mn4+ ions on the surface.
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Enteral nutrition (EN) increases hyperglycemia due to high carbohydrate concentrations while providing insufficient protein. The study tested whether an EN formula with very high-protein- and low-carbohydrate-facilitated glucose control... more
Enteral nutrition (EN) increases hyperglycemia due to high carbohydrate concentrations while providing insufficient protein. The study tested whether an EN formula with very high-protein- and low-carbohydrate-facilitated glucose control delivered higher protein concentrations within a hypocaloric protocol. This was a multicenter, randomized, open-label clinical trial with parallel design in overweight/obese mechanically ventilated critically ill patients prescribed 1.5 g protein/kg ideal body weight/day. Patients received either an experimental very high-protein (37%) and low-carbohydrate (29%) or control high-protein (25%) and conventional-carbohydrate (45%) EN formula. A prespecified interim analysis was performed after enrollment of 105 patients (52 experimental, 53 control). Protein and energy delivery for controls and experimental groups on days 1-5 were 1.2 ± 0.4 and 1.1 ± 0.3 g/kg ideal body weight/day (P = .83), and 18.2 ± 6.0 and 12.5 ± 3.7 kcals/kg ideal body weight/day (P...
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Quelques proprietes physicochimiques des oxydes Cr1-x Cux Mn2 O4 (avec x = 0 ; 0,1; 0,3; 0,5; 0,75; 1) de structure spinelle quadratique, prepares par decomposition thermique de solutions de nitrates ont ete etudiees. Nous montrons qu’il... more
Quelques proprietes physicochimiques des oxydes Cr1-x Cux Mn2 O4 (avec x = 0 ; 0,1; 0,3; 0,5; 0,75; 1) de structure spinelle quadratique, prepares par decomposition thermique de solutions de nitrates ont ete etudiees. Nous montrons qu’il est possible de proposer la repartition des divers cations entre sites tetraedriques et octaedriques a partir de plusieurs series de mesures : parametres de la maille, thermogravimetrie sous vide, masse volumique et degre d’oxydation moyen ainsi que susceptibilite magnetique et conductivite electrique en fonction de la temperature. Les resultats obtenus sont en accord avec les repartitions cationiques proposees par l’etude cristallographique. L’accord obtenu avec les mesures experimentales est satisfaisant.
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... Abstract | PDF (617 K) | View Record in Scopus | Cited By in Scopus (13). RN Singh, M. Hamdani, JF Koenig, G. Poillerat, JL Gautier and P. Chartier, J. Appl. Electrochem. ... Chem. 34 (1997), p. 367. LC Schumacher, IB Holzhueter, IR... more
... Abstract | PDF (617 K) | View Record in Scopus | Cited By in Scopus (13). RN Singh, M. Hamdani, JF Koenig, G. Poillerat, JL Gautier and P. Chartier, J. Appl. Electrochem. ... Chem. 34 (1997), p. 367. LC Schumacher, IB Holzhueter, IR Hill and MJ Dignam, Electrochim. ...
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A program for automatic scaling of technologies is presented. Its purpose is to determine expectable performances of submicron Enhancement-Depletion NMOS technologies. A ripple carry adder test circuit has been realized to show that high... more
A program for automatic scaling of technologies is presented. Its purpose is to determine expectable performances of submicron Enhancement-Depletion NMOS technologies. A ripple carry adder test circuit has been realized to show that high performances are really usable in complex circuits. Thus with ten logic layers and an average Fan Out about 3, this adder circuit can work with a
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The surface characterization of CdTe QDs synthesized by a novel procedure using glutathione (GSH), low temperatures (60 to 90 °C) and K2TeO3 as the eTe precursor is reported. Fluorescence of the produced QDs is stable in the pH range 6e13... more
The surface characterization of CdTe QDs synthesized by a novel procedure using glutathione (GSH), low temperatures (60 to 90 °C) and K2TeO3 as the eTe precursor is reported. Fluorescence of the produced QDs is stable in the pH range 6e13 and QDs inside eukaryotic cells are highly fluorescent. The surface composition of GSH-CdTe QDs with different spectroscopic properties and particle size distributions was determined by XPS. The XPS analysis indicated that the QDs are essentially CdTe, although all nanoparticles contain 12e24% of CdO (and in one case also TeO2). GSH decomposes with reaction time releasing small amounts of S�2 ions that react with Cd(Te) to yield Cd(Te)S in a smaller amount than that of CdTe. Finally, the use of QDs in fluorescence mediated immunodetection of bacterial pathogens has been evaluated.
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Two different options are available for submicron SOI devices: one is to keep the silicon thickness relatively thick, about 100 nm, in using a complex architecture as for bulk devices; the second one is to reduce the silicon film... more
Two different options are available for submicron SOI devices: one is to keep the silicon thickness relatively thick, about 100 nm, in using a complex architecture as for bulk devices; the second one is to reduce the silicon film thickness below 50nm for sub 0.25 μm devices, in order to obtain fully depleted devices. The main problem in this last
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CMOS circuits with feature sizes scaled down to 0.5μm [1],[2] and even less [3],[4] have already been reported. In this paper, we report the fabrication of half micron CMOS using mixed e-beam/optical lithography and Rapid Thermal... more
CMOS circuits with feature sizes scaled down to 0.5μm [1],[2] and even less [3],[4] have already been reported. In this paper, we report the fabrication of half micron CMOS using mixed e-beam/optical lithography and Rapid Thermal Annealing (RTA) for both BPSG reflow and junction activation. The aim of this work is to characterize devices and to compare speed performances of demonstrator circuits such as ring oscillator and 16kxl SRAM fabricated using either 0.5μm CMOS advanced technology at a 3.3V supply voltage or a 0.8μm CMOS at 5V.
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ABSTRACT
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ABSTRACT It is shown that pure Co3O4 and MnCo2O4 films can be prepared at 150 °C by spray pyrolysis of the metal nitrate aqueous solutions, provided that the flow rate and concentrations are lowered and optimized in comparison with... more
ABSTRACT It is shown that pure Co3O4 and MnCo2O4 films can be prepared at 150 °C by spray pyrolysis of the metal nitrate aqueous solutions, provided that the flow rate and concentrations are lowered and optimized in comparison with classical procedures, and that undecomposed nitrates are further eliminated by prolonged washing. High roughness factors are obtained, yielding electrodes with a higher activity for the oxygen evolution reaction than electrodes prepared by conventional spray pyrolysis at higher temperatures.
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ABSTRACT Electrocatalytic oxygen evolution on Cu1.4Mn1.6O4 thin films in KOH solutions was studied. The oxide films were prepared on non-conducting glasses, glass-CdO films and nickel foils at 530°C by spray pyrolysis. The oxide films... more
ABSTRACT Electrocatalytic oxygen evolution on Cu1.4Mn1.6O4 thin films in KOH solutions was studied. The oxide films were prepared on non-conducting glasses, glass-CdO films and nickel foils at 530°C by spray pyrolysis. The oxide films were characterized by X-ray diffraction analysis, scanning electron microscopy, electrochemical stability and roughness factor measurements. The electrocatalytic studies were carried out in the stationary state by potentiostatic polarization techniques (potential corrected for ohmic drop). The influence of deposited oxide weight and the substrate effect on the electrochemical reactivities is shown. On the nickel substrate oxygen evolution was observed to occur at a lower potential than on the CdO substrate. The reaction order ∂ log i/∂ log COH- was found to be between 1.2 and 1.4 and was related to applied potential. Tafel slopes decreased with increased film thickness. Electrokinetic parameters suggest similar mechanisms for oxygen evolution on both substrates.
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... M. Gracia* , JF Marco , JR Gancedo , J. Ortiz , R. Pastene and JL Gautier . Instituto de Qu mica F sica ... 10. R os, E.; Chen, Y.-Y.; Gracia, M.; Marco, JF; Gancedo, JR; Gautier, JL Electrochim. Acta 2001, 47, 559 566 ...
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In this work, we have studied the multilayered polypyrrole(PPy)/oxide composite electrode on glassy carbon (GC) having the structure GC/PPy/PPy(Cu1.4Mn1.6O4)/PPy using X-ray Photoelectron Spectroscopy and Mn K-edge and Cu K-edge XANES and... more
In this work, we have studied the multilayered polypyrrole(PPy)/oxide composite electrode on glassy carbon (GC) having the structure GC/PPy/PPy(Cu1.4Mn1.6O4)/PPy using X-ray Photoelectron Spectroscopy and Mn K-edge and Cu K-edge XANES and EXAFS. The mixed oxide particles have been incorporated into the PPy matrix simultaneously to the electropolymerization of Py from a solution containing 0.1 M Py+0.15 M KCl+Cu1.4Mn1.6O4. The XPS data have
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... Publisher: Issue Date: 2004. ???metadata.dc.subject.productividad???: ARTICULOS INTERNACIONALES-1020066. ???metadata.dc.creator.projectrelation???: JUAN LUIS GAUTIER ZAMORA EDMUNDO ISMAEL RIOS VILCHES. Description: Completo. ...
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We have studied the electrochemical behaviour induced by polarization in sandwich-type composite electrodes with the structure GC/PPy/PPy(Ox)/PPy where GC stands for glassy carbon, PPy for polypyrrole and Ox for Cu1.4Mn1.6O4... more
We have studied the electrochemical behaviour induced by polarization in sandwich-type composite electrodes with the structure GC/PPy/PPy(Ox)/PPy where GC stands for glassy carbon, PPy for polypyrrole and Ox for Cu1.4Mn1.6O4 nanoparticles. The electrodes were polarized at −0.45V/SCE in 0.15M KCl aqueous solution at pH 2.2 either saturated in Ar or O2 at 25°C. The changes occurring on these electrodes were
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Abstract Li, Co and Ni mixed oxides of composition LiNi x Co 2 − x O 4 (x = 0.25, 0.5, 0.75 and 1) were prepared at 280 °C by the Pechini sol–gel method. The Rietveld refinement of the X-ray diffraction data indicated that all the... more
Abstract Li, Co and Ni mixed oxides of composition LiNi x Co 2 − x O 4 (x = 0.25, 0.5, 0.75 and 1) were prepared at 280 °C by the Pechini sol–gel method. The Rietveld refinement of the X-ray diffraction data indicated that all the obtained compounds crystallize in the Fd3m space group characteristic of cubic spinel-related oxides. XPS studies on these oxides reveal the presence of Ni 2 + , Ni 3 + , Co 3 + and Co 4 + ions at the surface. The diffusion coefficients of the Li + ion in the oxide lattice, determined by EIS measurements, are larger (10 − 13 cm 2 s − 1 ≤ D ≤ 10 − 10 cm 2 s − 1 ) than that shown by the non-substituted cobalt-lithium oxide, LiCo 2 O 4 (D = 10 − 16 cm 2 s − 1 ) and present similar values to those of layered oxides of related composition.
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ABSTRACT Cobalt oxide nanocrystals of size 17-21 nm were synthesized by a simple reaction between cobalt acetate (II) and dodecylamine. On the other hand, micrometric Co3O4 was prepared using the ceramic method. The structural examination... more
ABSTRACT Cobalt oxide nanocrystals of size 17-21 nm were synthesized by a simple reaction between cobalt acetate (II) and dodecylamine. On the other hand, micrometric Co3O4 was prepared using the ceramic method. The structural examination of these materials was performed using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM and HRTEM). XRD studies showed that the oxides were pure, well-crystallized, spinel cubic phases with a-cell parameter of 0.8049 nm and 0.8069 nm for the nano and micro-oxide, respectively. The average particle size was 19 nm (nano-oxide) and 1250 μm (micro-oxide). Morphological studies carried out by SEM and TEM analyses have shown the presence of octahedral particles in both cases. Bulk and surface properties investigated by X-ray photoelectron spectroscopy (XPS), point zero charge (pzc), FTIR and cyclic voltammetry indicated that there were no significant differences in the composition on both materials. The magnetic behaviour of the samples was determined using a vibrating sample magnetometer. The compounds showed paramagnetic character and no coercivity and remanence in all cases. Galvanostatic measurements of electrodes formed with nanocrystals showed better performance than those built with micrometric particles.
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We have studied the electrochemical behaviour induced by polarization in sandwich-type composite electrodes with the structure GC/PPy/PPy(Ox)/PPy where GC stands for glassy carbon, PPy for polypyrrole and Ox for Cu1.4Mn1.6O4... more
We have studied the electrochemical behaviour induced by polarization in sandwich-type composite electrodes with the structure GC/PPy/PPy(Ox)/PPy where GC stands for glassy carbon, PPy for polypyrrole and Ox for Cu1.4Mn1.6O4 nanoparticles. The electrodes were polarized at −0.45V/SCE in 0.15M KCl aqueous solution at pH 2.2 either saturated in Ar or O2 at 25°C. The changes occurring on these electrodes were
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ABSTRACT The authors present results on fabricating ultra-thin silicon nanowires on insulators and characterizing their electrical conductivity. The silicon nanowires were fabricated by atomic force microscopy lithography on ultra-thin (8... more
ABSTRACT The authors present results on fabricating ultra-thin silicon nanowires on insulators and characterizing their electrical conductivity. The silicon nanowires were fabricated by atomic force microscopy lithography on ultra-thin (8 nm) silicon on insulator substrates. At such minute thicknesses, the device exhibits high sensitivity to the charges trapped at the Si / SiO 2 interface. This leads to an unusual behavior of the electrical conductivity of the nanowires as a function of drain-source and gate voltages.
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Magnetic properties of two spinel oxides solid solutions, Cu1+ xMn2− xO4 and Ni1+ xMn2− xO4, are reported. These series are characterized by two magnetic transitions: the upper one, of ferrimagnetic type, occurs at about 85K (for... more
Magnetic properties of two spinel oxides solid solutions, Cu1+ xMn2− xO4 and Ni1+ xMn2− xO4, are reported. These series are characterized by two magnetic transitions: the upper one, of ferrimagnetic type, occurs at about 85K (for copper-based) and at 105110K (for ...
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... The oxide film deposited on titanium was dried in ... The oxide prepared using the spray pyrolysis technique showed a pure spinel phase Fd3m-type, with crystallites 35 nm in size and a unit a-cell parameter that measured 0.8085 nm in... more
... The oxide film deposited on titanium was dried in ... The oxide prepared using the spray pyrolysis technique showed a pure spinel phase Fd3m-type, with crystallites 35 nm in size and a unit a-cell parameter that measured 0.8085 nm in agreement with our previous reports [10]. ...
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... Patricia BARAHONA 1,2 , Vincent BODENEZ 1 , Thierry GUIZOUARN 1 , Octavio PEÑA 1,* , Juan ORTIZ 3,& , Edmundo RIOS 3 , Rubén PASTENE 3 ... of lithium, chromium(III), manganese(II), nickel(III) and iron(III) nitrates were... more
... Patricia BARAHONA 1,2 , Vincent BODENEZ 1 , Thierry GUIZOUARN 1 , Octavio PEÑA 1,* , Juan ORTIZ 3,& , Edmundo RIOS 3 , Rubén PASTENE 3 ... of lithium, chromium(III), manganese(II), nickel(III) and iron(III) nitrates were prepared from the following nitrate salts: LiNO 3 , Cr ...