We constrain two dynamical dark energy models that are parametrized by the logarithm form of and the oscillating form of . Comparing with the Chevallier-Polarski-Linder (CPL) model, the two parametrizations for dark e...We constrain two dynamical dark energy models that are parametrized by the logarithm form of and the oscillating form of . Comparing with the Chevallier-Polarski-Linder (CPL) model, the two parametrizations for dark energy can explore the whole evolution history of the universe properly. Using the current mainstream observational data including the cosmic microwave background data and the baryon acoustic oscillation data as well as the type Ia supernovae data, we perform the X<sup>2</sup> statistic analysis to global fit these models, finding that the logarithm parametrization and the oscillating parameterization are almost as well as the CPL scenario in fitting these data. We make a comparison for the impacts of the dynamical dark energy on the cosmological constraints on the total mass of active neutrinos. We find that the logarithm parametrization and the oscillating parameterization can increase the fitting values of Σm<sub>v</sub>. Looser constraints on Σm<sub>v</sub> are obtained in the logarithm and oscillating models than those derived in the CPL model. Consideration of the possible mass ordering of neutrinos reveals that the most stringent constraint on Σm<sub>v</sub> appears in the degenerate hierarchy case.展开更多
A comprehensive study of the phase composition, microstructure evolution, microhardness and wear performance of WC-12 Co composite coatings fabricated by laser cladding using coaxial powder-feed mode was presented. It...A comprehensive study of the phase composition, microstructure evolution, microhardness and wear performance of WC-12 Co composite coatings fabricated by laser cladding using coaxial powder-feed mode was presented. It was shown that a combination of high scan speed and high laser energy density made WC on the edge of WC-12 Co composite powders partially melt in liquid Co and 304 stainless steel matrix, and then new carbides consisting of lamellar WC and herringbone M3 W3 C(M=Fe,Co) were formed. Meanwhile, WC-12 Co composite coatings with no porosity, cracks and drawbacks like decarburization were obtained, showing high densification and good metallurgical bonding with the substrate. Furthermore, a considerably high microhardness of HV0.3 1500-1600, low coefficient of friction of 0.55 and wear rate of(2.15±0.31)×10-7 mm3/(N·m) were achieved owing to the synergistic effect of excellent metallurgical bonding and fine microstructures of composite coating under laser power of 1500 W.展开更多
The graphene/mesocarbon microbead(MCMB)composite is assessed as an anode material with a high capacity for lithium-ion batteries.The composite electrode exhibits improved cycling stability and rate capability,deliveri...The graphene/mesocarbon microbead(MCMB)composite is assessed as an anode material with a high capacity for lithium-ion batteries.The composite electrode exhibits improved cycling stability and rate capability,delivering a high initial charge/discharge capacity of 421.4 mA·h/g/494.8 mA·h/g as well as an excellent capacity retention over 500 cycles at a current density of 40 mA/g.At a higher current density of 800 mA/g,the electrode still retains 35%of its initial capacity which exceeds the capacity retention of pure graphene or MCMB reference electrodes.Cyclic voltammetry and electrochemical impedance spectroscopy reveal that the composite electrode favors electrochemical kinetics as compared with graphene and MCMB separately.Superior electrochemical properties suggest a strong synergetic effect between highly conductive graphene and MCMB.展开更多
文摘We constrain two dynamical dark energy models that are parametrized by the logarithm form of and the oscillating form of . Comparing with the Chevallier-Polarski-Linder (CPL) model, the two parametrizations for dark energy can explore the whole evolution history of the universe properly. Using the current mainstream observational data including the cosmic microwave background data and the baryon acoustic oscillation data as well as the type Ia supernovae data, we perform the X<sup>2</sup> statistic analysis to global fit these models, finding that the logarithm parametrization and the oscillating parameterization are almost as well as the CPL scenario in fitting these data. We make a comparison for the impacts of the dynamical dark energy on the cosmological constraints on the total mass of active neutrinos. We find that the logarithm parametrization and the oscillating parameterization can increase the fitting values of Σm<sub>v</sub>. Looser constraints on Σm<sub>v</sub> are obtained in the logarithm and oscillating models than those derived in the CPL model. Consideration of the possible mass ordering of neutrinos reveals that the most stringent constraint on Σm<sub>v</sub> appears in the degenerate hierarchy case.
基金Project(20171ACE50018)supported by the Key Research and Development Program of Jiangxi Province,ChinaProject(2017-YZD2-16)supported by the Key Research Project of Jiangxi Academy of Sciences,China。
文摘A comprehensive study of the phase composition, microstructure evolution, microhardness and wear performance of WC-12 Co composite coatings fabricated by laser cladding using coaxial powder-feed mode was presented. It was shown that a combination of high scan speed and high laser energy density made WC on the edge of WC-12 Co composite powders partially melt in liquid Co and 304 stainless steel matrix, and then new carbides consisting of lamellar WC and herringbone M3 W3 C(M=Fe,Co) were formed. Meanwhile, WC-12 Co composite coatings with no porosity, cracks and drawbacks like decarburization were obtained, showing high densification and good metallurgical bonding with the substrate. Furthermore, a considerably high microhardness of HV0.3 1500-1600, low coefficient of friction of 0.55 and wear rate of(2.15±0.31)×10-7 mm3/(N·m) were achieved owing to the synergistic effect of excellent metallurgical bonding and fine microstructures of composite coating under laser power of 1500 W.
基金supported by the Special Support Program of Guangdong Province for High-level Talents(No.2014TX01N014)the Guangdong Provincial for Science&Technology(Nos.2013B091300017 and 2014A050503050)+1 种基金the Guangzhou Municipal for Science&Technology(No.201423/2014Y2-00219)the Dongguan Municipal Collaboration for Industry&Science(No.2013509104210),China
基金Project supported by the National Basic Research Program(973)of China(No.2011CB706506)the National Natural Science Foundation of China(No.51375438)the Zhejiang Provincial Natural Science Foundation of China(No.LQ13F030003)
基金Project supported by the National Natural Science Foundation of China(No.21573239)the Guangdong Provincial Project for Science and Technology(Nos.2014TX01N14,2015B010135008,and 2016B010114003)+1 种基金the Guangzhou Municipal Project for Science and Technology(No.201509010018)the K.C.WONG Education Foundation,China。
文摘The graphene/mesocarbon microbead(MCMB)composite is assessed as an anode material with a high capacity for lithium-ion batteries.The composite electrode exhibits improved cycling stability and rate capability,delivering a high initial charge/discharge capacity of 421.4 mA·h/g/494.8 mA·h/g as well as an excellent capacity retention over 500 cycles at a current density of 40 mA/g.At a higher current density of 800 mA/g,the electrode still retains 35%of its initial capacity which exceeds the capacity retention of pure graphene or MCMB reference electrodes.Cyclic voltammetry and electrochemical impedance spectroscopy reveal that the composite electrode favors electrochemical kinetics as compared with graphene and MCMB separately.Superior electrochemical properties suggest a strong synergetic effect between highly conductive graphene and MCMB.
