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1.
Limited-trial Chase decoding 总被引:1,自引:0,他引:1
Arico G. Weber J.H. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2003,49(11):2972-2975
Chase decoders permit flexible use of reliability information in algebraic decoding algorithms for error-correcting block codes of Hamming distance d. The least complex version of the original Chase algorithms uses roughly d/2 trials of a conventional binary decoder, after which the best decoding result is selected as the final output. On certain channels, this approach achieves asymptotically the same performance as maximum-likelihood (ML) decoding. In this correspondence, the performance of Chase-like decoders with even less trials is studied. Most strikingly, it turns out that asymptotically optimal performance can be achieved by a version which uses only about d/4 trials. 相似文献
2.
Propane conversion over a Ru/CGO catalyst and its application in intermediate temperature solid oxide fuel cells 总被引:1,自引:0,他引:1
M. Lo Faro D. La Rosa G. Monforte V. Antonucci A.S. Arico P. Antonucci 《Journal of Applied Electrochemistry》2007,37(2):203-208
A Ru/CGO catalyst was investigated in combination with a Cu current collector for the direct electro-oxidation and internal
reforming of propane in a solid oxide fuel cell. The electrochemical power densities for the direct oxidation were larger
than in the internal reforming process at 750 °C. The electrochemical performance in the presence of propane was significantly
affected by the polarization resistance which was about three times larger than that obtained for the SOFC fed with hydrogen
at 750 °C. However, out-of-cell steam reforming tests showed a C3H8 conversion to syngas approaching 90% at 800 °C. Thus, significant enhancements may be achieved by properly optimizing the
anode structure. No formation of carbon deposits was observed both upon operation of the anode in the direct oxidation and
internal reforming processes at 750 °C. 相似文献
3.
A. Pistone A. S. Arico P. L. Antonucci D. Silvestro V. Antonucci 《Solar Energy Materials & Solar Cells》1998,53(3-4)
Thin film p-ZnCuTe semiconductors were synthesized by electrodeposition. The deposition mechanism was investigated by cyclic voltammetry; formation of the ternary compound, having the cubic structure of ZnTe, was obtained upon annealing at 400°C, as confirmed by X-ray diffraction. A direct energy gap of 1.7 eV was determined by optical absorption experiments. Measurements of the Hall effect and Van der Pauw conductivity showed an increase of carrier concentration and a decrease of sheet resistance for ZnCuTe with respect to zinc telluride. 相似文献
4.
A. Stassi C. D’urso V. Baglio A. Di Blasi V. Antonucci A.S. Arico A.M. Castro Luna A. Bonesi W.E. Triaca 《Journal of Applied Electrochemistry》2006,36(10):1143-1149
A 60 wt% Pt–Fe/C and a 60 wt% Pt–Cu/C catalysts with Fe and Cu content of 5 wt% were prepared by using a combination of colloidal and incipient wetness methods; this has allowed synthesis of small nanostructured crystalline bimetallic catalysts with particle size less than 3 nm and with a suitable degree of alloying. These materials were studied in terms of structure, morphology and composition using XRD, XRF and TEM techniques. The electrocatalytic behaviour for ORR of the catalysts was investigated using the rotating disk technique and compared to that of a pure Pt catalyst with similar particle size. No improvement in performance was recorded with the Pt–Cu compared to Pt catalyst, whereas, a promoting effect in enhancing the ORR was observed for the Pt–Fe catalyst both with and without methanol in the oxygen-saturated electrolyte solution. 相似文献
5.
A. Di Blasi C. D’Urso V. Baglio V. Antonucci A. S. Arico’ R. Ornelas F. Matteucci G. Orozco D. Beltran Y. Meas L. G. Arriaga 《Journal of Applied Electrochemistry》2009,39(2):191-196
IrO2–RuO2, IrO2–Pt and IrO2–Ta2O5 electrocatalysts were synthesized and characterized for the oxygen evolution in a Solid Polymer Electrolyte (SPE) electrolyzer.
These mixtures were characterized by XRD and SEM. The anode catalyst powders were sprayed onto Nafion 117 membrane (catalyst
coated membrane, CCM), using Pt catalyst at the cathode. The CCM procedure was extended to different in-house prepared catalyst
formulations to evaluate if such a method could be applied to electrolyzers containing durable titanium backings. The catalyst
loading at the anode was about 6 mg cm−2, whereas 1 mg cm−2 Pt was used at the cathode. The electrochemical activity for water electrolysis was investigated in a single cell SPE electrolyzer
at 80 °C. It was found that the terminal voltage obtained with Ir–Ta oxide was slightly lower than that obtained with IrO2–Pt and IrO2–RuO2 at low current density (lower than 0.15 A cm−2). At higher current density, the IrO2–Pt and IrO2–RuO2 catalysts performed better than Ir–Ta oxide. 相似文献
6.
A. StassiI. Gatto E. PassalacquaV. Antonucci A.S. Arico L. MerloC. Oldani E. Pagano 《Journal of power sources》2011,196(21):8925-8930
A new Aquivion™ E79-03S short-side chain perfluorosulfonic membrane with a thickness of 30 μm (dry form) and an equivalent weight (EW) of 790 g/equiv recently developed by Solvay-Solexis for high-temperature operation was tested in a pressurised (3 bar abs.) polymer electrolyte membrane (PEM) single cell at a temperature of 130 °C. For comparison, a standard Nafion™ membrane (EW 1100 g/equiv) of similar thickness (50 μm) was investigated under similar operating conditions. Both membranes were tested for high temperature operation in conjunction with an in-house prepared carbon supported Pt electrocatalyst. The electrocatalyst consisted of nanosized Pt particles (particle size ∼2 nm) dispersed on a high surface area carbon black. The electrochemical tests showed better performance for the Aquivion™ membrane as compared to Nafion™ with promising properties for high temperature PEM fuel cell applications. Beside the higher open circuit voltage and lower ohmic constraints, a higher electrocatalytic activity was observed at high temperature for the electrocatalyst-Aquivion™ ionomer interface indicating a better catalyst utilization. 相似文献
7.
T. Denaro V. Baglio M. Girolamo V. Antonucci A. S. Arico’ F. Matteucci R. Ornelas 《Journal of Applied Electrochemistry》2009,39(11):2173-2179
The structural and morphologic properties of different carbonaceous materials were studied by X-ray diffraction (XRD), Brunauer–Emmet–Teller (BET) porosimetry and transmission electron microscopy (TEM) analyses. The electrochemical behaviour of these powders used as counter electrode in dye-sensitized solar cells (DSSCs) was investigated by polarization experiments and electron impedance spectroscopy. Results were compared with DSSC using Pt as counter electrode. All DSSCs based on the carbonaceous materials showed conversion efficiencies higher than those equipped with Pt. Among the various carbon materials investigated, Acetylene Black in conjunction with graphite showed the best performance. This was interpreted from the physico-chemical analysis as due to a compromise between pores accessibility for the I3 ? reactant presents in electrolyte and appropriate surface graphiticity index of this carbonaceous material. A high degree of graphitization for the carbon black was found to enhance electron conduction and charge transfer properties. 相似文献
8.
Aiyu Yan Vasiliki Maragou Antonino Arico Mojie Cheng Panagiotis Tsiakaras 《Applied catalysis. B, Environmental》2007,76(3-4):320-327
The effect of carbon dioxide on the chemical stability of a Ba0.5Sr0.5Co0.8Fe0.2O3−δ cathode in the real reaction environment at 450 °C was investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), temperature programmed desorption (TPD), X-ray diffraction (XRD) and electrochemical impedance spectra (EIS) techniques. It was found that the presence even of very small quantities of CO2 seriously deteriorates the fuel cell performance at 450 °C. XPS, TPD and XRD results strongly evidenced the formation of carbonates involving strontium and possibly barium after the BSCF cathode was operated in 1% CO2/O2 gas mixture at 450 °C for 24 h. SEM-EDX analysis of the BSCF cathode surface, after treatment in CO2/O2 environment at 450 °C, showed small particles on the surface probably associated with a carbonate phase and a segregated phase of the perovskite. The corresponding EDX spectra confirmed the presence of a carbonate layer and also revealed the surface enrichment of strontium and barium elements. EIS results indicated that both ohmic and polarization resistances increased gradually with the introduction of carbon dioxide in the oxidant stream, which could be interpreted by the decreased oxygen reduction kinetics and the formation of carbonate insulating layer. 相似文献
9.
R.S. Amin K.M. El-Khatib S. Siracusano V. Baglio A. Stassi A.S. Arico 《International Journal of Hydrogen Energy》2014
Noble metal oxides (IrOx, RuOx) and valve metal oxides (SnOx and VOx) have been investigated as promoters of Pt electrocatalyst for methanol oxidation in acidic environment. Pt modification was made using low oxide content (5 wt%) in order to evaluate the possibility of using such oxide promoter in a multifunctional catalyst. At this low level of oxide content, IrOx provided a larger promoting effect than RuOx. This occurred in the absence of specific alloying with Pt and also in the presence of lower catalyst dispersion. The electrocatalytic enhancement produced by the valve metal oxides was significantly lower than IrOx and RuOx. These results are interpreted in terms of the different water displacement mechanism for the various oxides. Such evidences seem to indicate that a multifunctional catalyst may represent a valid route to enhance methanol electro-oxidation. 相似文献