| 1. |
- Ablikim, M., et al.
(författare)
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Measurements of (XcJ)-> K+K-K+K- decays
- 2006
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:3, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- Using 14M psi(2S) events taken with the BESII detector, chi(cJ) -> 2(K+K-) decays are studied. For the four-kaon final state, the branching fractions are B(chi(c0,1,2) ->.2(K+K-)) = (3.48 +/- 0.23 +/- 0.47) x 10(-3), (0.70 +/- 0.13 +/- 0.10) x 10(-3), and (2.17 +/- 0.20 +/- 0.31) x 10(-3). For the phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi(c0,1,2) -> phi K+K-) = (1.03 +/- 0.22 +/- 0.15) x 10(-3), (0.46 +/- 0.16 +/- 0.06) x 10(-3), and (1.67 +/- 0.26 +/- 0.24) x 10(-4). For the phi phi final state, B(chi(c0,2) -> phi phi) = (0.94 +/- 0.21 +/- 0.13) x 10(-3) and (1.70 +/- 0.30 +/- 0.25) x 10(-3).
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| 2. |
- Rong-Li, Jia, et al.
(författare)
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Preparation and characterization of Pt/superfine mesocarbon microbead powers electrocatalysts
- 2006
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Ingår i: Journal of Fuel Cell Science and Technology. - : ASME International. - 1550-624X .- 1551-6989. ; 3:3, s. 358-360
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Tidskriftsartikel (refereegranskat)abstract
- Superfine mesocarbon microbead powders (SFMCMBs) as the new supports for platinum electrocatalysts were first investigated. The Pt/SFMCMB electrocatalysts were prepared by an impregnation-reduction method, with hexachloroplatinic acid as the platinum precursor and formaldehyde as the reducing agent. The catalysts were characterized with x-ray diffraction (XRD), field emission gun transmission electron microscope (TEM), and electrochemical analysis. TEM photos showed the platinum particles were dispersed uniformly on the surface of SFMCMBs and there existed a little aggregation of platinum particles in the Pt/SFMCMB catalysts. The TEM photos showed the existence of the platinum on the supports-where the average platinum particle size were 4-6 nm. The electrochemical analysis proved that SFMCMBs are excellent candidates to be used as the support of platinum electrocatalyst for methanol electrochemical oxidation as the potential catalyst candidate for direct methanol fuel cells (DMFCs).
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| 3. |
- Rong-Li, J., et al.
(författare)
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Preparation of platinum supported on carbon blacks with different surface chemical characteristics
- 2005
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Ingår i: Proceedings of the 3rd International Conference on Fuel Cell Science, Engineering, and Technology. - : ASME Press. - 0791837645 ; , s. 235-238
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Konferensbidrag (refereegranskat)abstract
- In a study of the preparation of Pt/C eletrocatalysts, a set of modified Vulcan XC-72R carbon black supports have been prepared by nitric acid or hydrogen peroxide oxidation, or thermal treatment in nitrogen flow. The supports obtained by these methods had largely identical pore structure, but different from the amount of surface oxygen-containing groups. The physical and surface chemical nature of the supports was characterized by XPS, BET, FTIR and acid-base titration. The above pre-treatment-carbon supported platinum catalysts were prepared by impregnation-reduction method with formaldehyde as the reducing agent, H2PtCl6 as precursor. The effect of the amount of surface oxygen-containing groups of Vulcan XC-72R carbon black on Pt/C catalysts dispersion was studied by the characterization with XRD and TEM. It has been found that decreasing the amount of surface oxygen-containing groups on carbon supports favored the platinum dispersion on the Pt/C catalysts.
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| 4. |
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