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We calculate the valence quark distribution functions of the π meson using the non-relativistic chiral constituent quark model. The π wave function is obtained by solving the two-body Schrödinger equation within the framework of constituent quark model. We transform the π wave function from the rest frame to the light cone or infinite momentum frame based on the Lorentz boost. The valence quark distributions at the initial evolution scale are obtained. The QCD evolution is given with the DGLAP equations with parton-parton recombination corrections. With tuning the valence up (down) quark mass to 70 MeV, the calculated valence up quark distributions at Q 2 = 20 GeV2 are in good agreement with the E615 experimental data. The structure functions F 2 π (x , Q 2) of pion are also calculated which consist with the H1 experimental data. The proposed mechanisms here could be also used to study other hadrons. [ABSTRACT FROM AUTHOR]

We present the polarized parton distribution functions from a QCD analysis of the worldwide polarized deep inelastic scattering data, based on the dynamical parton distribution model. All the sea quarks and gluons are dynamically generated from QCD radiations, with the nonperturbative input comprising only the polarized valence quark distributions. This approach leads to a simple parametrization, which has only seven free parameters. In the analysis, we apply the DGLAP equations with parton-parton recombination corrections. For the first step, the DGLAP equations, parton-parton recombination corrections, and experimental observable g 1 are all evaluated at the leading order. The parameterized nonperturbative input at an extremely low Q 0 2 reproduces well the spin-dependent structure functions measured at high Q 2. Comparisons with experimental observations and some other polarized parton distribution functions are also shown. Our results are in good agreement with the experimental data and consistent with some other parameterized models. Furthermore, our analysis presents the positive polarized gluon distribution and it suggests that the gluon distribution plays an important role to the proton spin content. The polarized antiquark distributions are non-zero at high Q 2 but quite small compared to polarized valence quark distributions, based on this dynamical parton model analysis. This analysis gives smaller statistical uncertainties for the polarized sea quark and gluon distributions, thanks to the fewer free parameters used for the parametrization of the initial polarized PDFs. [ABSTRACT FROM AUTHOR]

Valence quark distributions of pion at very low resolution scale Q 0 2 ∼ 0.1 GeV2 are deduced from a maximum entropy method, under the assumption that pion consists of only a valence quark and a valence anti-quark at such a low scale. Taking the obtained initial quark distributions as the nonperturbative input in the modified Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (with the GLR-MQ-ZRS corrections) evolution, the generated valence quark distribution functions at high Q 2 are consistent with the measured ones from a Drell-Yan experiment. The maximum entropy method is also applied to estimate the valence quark distributions at relatively higher Q 2 = 0.26 GeV 2. At this higher scale, other components (sea quarks and gluons) should be considered in order to match the experimental data. The first three moments of pion quark distributions at high Q 2 are calculated and compared with the other theoretical predictions. [ABSTRACT FROM AUTHOR]

The structure of Fe 2 O 3 @NiS/Co 3 S 4 composite was the agglomerate Fe 2 O 3 nanoparticles in situ covered with NiS/Co 3 S 4 nanosheets and the composite employed for high-performance supercapacitor electrode. [Display omitted] • The Fe 2 O 3 -based composite as cathode materials are few reports. • Synergetic effects between Fe 2 O 3 and NiCo-S improve the capacity and conductivity. • Fe 2 O 3 @Ni1Co1-S presented 3D stable open structure lead to the electrode stability. • The corresponding ASC device delivers considerable energy and power densities. Fe 2 O 3 -based cathode materials show high theoretical specific capacitance and a wide potential range, but it is limited development due to poor electrical conductivity, undesired rate capacity and long-term cycling stability. Herein, we introduce the interconnected NiS/Co 3 S 4 nanosheets grown on Fe 2 O 3 substrate (Fe 2 O 3 @NiS/Co 3 S 4) through a facile in situ solution vulcanization process. Because of the synergistic effect between the Fe 2 O 3 nanoparticles and NiCo-S nanosheets and its unique three-dimensional open structure providing abundant channels and active sites, it is deeply investigated the electrochemical performances as positive material of supercapacitors. Meanwhile, the electrode material exhibits specific capacity of 1213.7 F g−1 at 1 A g−1, about 64.7% capacity retention at 10 A g−1 and steady cycling performance about 85.2% retention after 5000 cycles at 5 A g−1. Finally, an asymmetric supercapacitor was assembled based on Fe 2 O 3 @NiS/Co 3 S 4 and active carbon as the positive and negative electrodes. The energy density is 43.8 Wh kg−1 at the power density of 810 W kg−1. At the same time, 92.4 % capacitance retention after 10,000 cycles at 5 A g−1 was obtained. [ABSTRACT FROM AUTHOR]