| 1. |
- Abelev, Betty, et al.
(författare)
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Long-range angular correlations on the near and away side in p-Pb collisions at root S-NN=5.02 TeV
- 2013
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 719:1-3, s. 29-41
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Tidskriftsartikel (refereegranskat)abstract
- Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5 < P-T,P-assoc < P-T,P-trig < 4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and p(T) bins, and the widths show no significant evolution with event multiplicity or p(T). These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved.
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| 2. |
- Abelev, Betty, et al.
(författare)
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Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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| 3. |
- Hu, Huiqing, et al.
(författare)
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Effects of composition on the electrochemical property and cell performance of single layer fuel cell
- 2015
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 275, s. 476-482
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the enhanced electrochemical performance of single layer fuel cells (SLFCs) based upon mixed ion and electron conductors is analyzed as a function of composition. We synthesize a series of Ce0.8Sm0.2O2-delta-Li0.3Ni0.6Cu0.07Sr0.03O2-delta (SDC-LNCS) with different weight ratios. The microstructure and morphology of the composite materials are characterized through X-ray diffraction (XRD), transmission electron microscope (TEM), and energy-dispersive X-ray spectrometer (EDS). Stability of the synthesized samples is evaluated by thermal gravity analysis (TGA). The SLFC with 6SDC-4LNCS exhibits a uniform distribution of the two compositions as well as demonstrates the highest power density of 312 mW cm-2 at 550 mu C. The performance is correlated to the balance of the conduction properties (ionic and electronic) of the functional SLFC layer. The results are a critical contribution to further development of this new energy transfer device.
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| 4. |
- Hu, Huiging, et al.
(författare)
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Time-dependent performance change of single layer fuel cell with Li0.4Mg0.3Zn0.3O/Ce0.8Sm0.2O2-delta composite
- 2014
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 39:20, s. 10718-10723
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Tidskriftsartikel (refereegranskat)abstract
- A Large-size engineering single layer fuel cell (SLFC) consisting of a nano-structured Li0.4Mg0.3Zn0.3O2-delta/Ce0.8Sm0.2O2-delta (LMZSDC) composite with an active area of 25 cm(2) (6 cm x 6 cm x 0.1 cm) is successfully fabricated. The SLFC is evaluated by testing the cell durability with a time-dependent degradation using an H-2 fuel and an air oxidant at 600 degrees C for over 120 h. A maximum power of 12.8 W (512 mW cm(-2)) is achieved at 600 degrees C. In the initial operation stage around 50 h, the cell's performance decreases from 12.8 to 11.2 W; however, after this point, the performance was consistently stable, and no significant degradation is observed in the current density or the cell performance. The device performed excellently at low temperatures with a delivered power output of more than 250 mW cm(-2) at a temperature as low as 400 degrees C. By curve fitting the X-ray photoelectron spectroscopy (XPS) results, the ratio of Ce3+/(Ce3++Ce4+) before and after the long-time operation is analyzed. The ratio increased from 28.2% to 31.4% in the electrolyte which indicates a reduction occurs in the beginning operation that causes an initial performance loss for the device power output and OCV. Electrochemical impedance analyses indicate that the LMZSDC had a high ionic transport, and the device had quick dynamic processes and, thus, a high fuel cell performance. The LMZSDC is a new type of ionic material that has been successfully applied to SLFCs.
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| 5. |
- Mat, Mahmut D., et al.
(författare)
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Development of cathodes for methanol and ethanol fuelled low temperature (300-600 degrees C) solid oxide fuel cells
- 2007
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 32:7, s. 796-801
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Tidskriftsartikel (refereegranskat)abstract
- We have made extensive efforts to develop various compatible cathode materials for the ceria-carbonate composite (CCC) electrolytes to be used in direct alcohol fuelled solid oxide fuel cells (DLFC). The following cathode materials were mainly investigated: (i) BSCF (BaSrCoFeO) perovskite oxide; (ii) LFN (LaFeO-based oxides, e.g. LaFe0.8Ni0.2O3) perovskite oxides; (iii) bi- or tri-phase metal oxides with or without lithiation. A number of copper- and nickel-based anode composites were also developed for methanol and ethanol with maximum catalytic activity. The tri-metal oxide (CuNiOx-ZnO) cathode produced the maximum power density output of 500 mW/cm(-2) at 580 degrees C for DLFC with methanol operation.
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| 6. |
- Zhu, Bin, et al.
(författare)
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Compatible cathode materials for high performance low temperature (300-600°C) solid oxide fuel cells
- 2006
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Ingår i: Proceedings of 4th International ASME Conference on Fuel Cell Science, Engineering and Technology, FUELCELL2006. - : ASMEDC.
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Konferensbidrag (refereegranskat)abstract
- We have made extensive efforts to develop various compatible electrode materials for the ceria-based composite (CBC) electrolytes, which have been, reported as most advanced LTSOFC electrolyte materials (Zhu, 2003). The electrode materials we have investigated can be classified as four categories: i) LSCCF (LaSrCoCaFeO) and BSCF perovskite oxides applied for our CBC electrolyte LTSOFCs; ii) LFN (LaFeO-based oxides, e.g. LaFe0.8Ni 0.2O3) perovskite oxides; iii) lithiated oxides: e.g. LiNiOx, LiVOx or LiCuOx are typical cathode examples for the CBC LTSOFCs; iv) other mixed oxide systems, most common in a mixture of two-oxide phases, such CuOx-NiOx, CuO-ZnO etc. systems with or without lithiation are developed for the CBC systems, especially for direct alcohol LTSOFCs. These cathode materials used for the CBC electrolyte LTSOFCs have demonstrated excellent performances at 300-600°C, e.g. 1000 mWcm-2 was achieved at 580°C. The LTSOFCs can be operated with a wide range of fuels, e.g. hydrogen, methanol, ethanol etc with great potential for applications.
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| 7. |
- Zhu, Bin, et al.
(författare)
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Development of low temperature solid oxide fuel cells
- 2006
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Ingår i: Proceedings of 4th International ASME Conference on Fuel Cell Science, Engineering and Technology. - : ASMEDC. - 0791837807 - 9780791837801
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Konferensbidrag (refereegranskat)abstract
- Based on innovative ceria-based composite (CBC) material advantages we have made strong efforts to make technical developments on scaling up material production, fabrication technologies on large cells and stack operated at low temperatures (300 to 600°C). Next generation materials for solid oxide fuel cells (SOFCs) have been developed based on abundant natural resources of the industrial grade mixed rare-earth carbonates named as LCP. Here we show the LCP-based materials used as functional electrolytes to achieve excellent fuel cell performances, 300-800 mWcm2 for low temperatures, exhibiting a great availability for industrialization and commercialization. Copyright
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| 8. |
- Zhu, Bin, et al.
(författare)
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Solid oxide fuel cell (SOFC) using industrial grade mixed rare-earth oxide electrolytes
- 2008
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 33:13, s. 3385-3392
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Tidskriftsartikel (refereegranskat)abstract
- This work reports on solid oxide fuel cells (SOFCs) based on abundant natural resources of industrial grade mixed rare-earth carbonates and composites. The materials possessed natural compositions and nano-scale particles. The electrolytes made from these materials were able to achieve excellent fuel cell performances, 300-800 mW/cm(2), at low temperatures (LT: 300-600 degrees C). Ionic transport mechanism, two-phase interface functions and composite role in electrolytes as well as resulted advanced fuel cell performances are discussed.
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| 9. |
- Abelev, Betty, et al.
(författare)
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Underlying Event measurements in pp collisions at root s=0.9 and 7 TeV with the ALICE experiment at the LHC
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.
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| 10. |
- Hu, Huiqing, et al.
(författare)
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Scaled up low-temperature SOFCs with symmetrical electrode for applications
- 2015
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Ingår i: Journal of Solid State Electrochemistry. - : Springer Science and Business Media LLC. - 1432-8488 .- 1433-0768. ; 19:8, s. 2361-2368
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a new type of the Mg0.4Zn0.6O/Ce0.8Sm0.2O2-delta (MZSDC) composite electrolyte was synthesized using a co-precipitation method. Large-sized engineering cells have been fabricated and tested to meet the demands of applications. X-ray diffraction scanning electron microscopy and X-ray photoelectron spectroscopy have been employed to characterize the microstructure and the morphology of the synthesized samples. MZSDC is a composite system. X-ray electron spectroscopy shows that Ce (3d) binding energy shifted from high to low and the ratio of Ce3+ decreased in comparison to pure CeO2, due to the doping effect. The doping and composite caused the material to have an excellent electrical property, 0.089 S center dot cm(-1), and device performance, with a maximum power of 16.4 W (648 mW center dot cm(-2)) achieved at 600 A degrees C for a larger-sized (6 cm x 6 cm x 1 mm) fuel cell. The open circuit voltage and power of the fuel cell only slightly degrades (less than 1 %) after continually tested for 100 h. This is the first report regarding the large size engineering cell performance for using this new composite electrolyte with both excellent performance and low cost.
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