[en] The three-Coulomb-wave (3C) model is applied to study the single ionization of helium by 2 MeV/amu C⁶⁺ impact. Fully differential cross sections (FDCS) are calculated in the scattering plane and the results are compared with experimental data and other theoretical predictions. It is shown that the 3C results of the recoil peak are in very good agreement with experimental observations, and variation of the position of the binary peak with increasing momentum transfer also conforms better to the experimental results. Furthermore, the contributions of different scattering amplitudes are discussed. It turns out that the cross sections are strongly influenced by the interference of these amplitudes

[en] We report new results of triple differential cross sections for the single ionization of helium by 1-KeV electron impact at the ejection energy of 10 eV. Investigations have been made for both the perpendicular plane and the plane perpendicular to the momentum transfer geometries. The present calculation is based on the three-Coulomb wave function. Here we have also incorporated the effect of target polarization in the initial state. A comparison is made between the present calculation with the results of other theoretical methods and a recent experiment [Dürr M, Dimopoulou C, Najjari B, Dorn A, Bartschat K, Bray I, Fursa D V, Chen Z, Madison D H and Ullrich J 2008 Phys. Rev. A 77 032717]. At an impact energy of 1 KeV, the target polarization is found to induce a substantial change of the cross section for the ionization process. We observe that the effect of target polarization plays a dominant role in deciding the shape of triple differential cross sections. (atomic and molecular physics)

[en] Nematic order and its fluctuations have been widely found in iron-based superconductors. Above the nematic order transition temperature, the resistivity shows a linear relationship with the uniaxial pressure or strain along the nematic direction and the normalized slope is thought to be associated with nematic susceptibility. Here we systematically studied the uniaxial pressure dependence of the resistivity in Sr_1−xBa_xFe_1.97Ni_0.03As₂, where nonlinear behaviors are observed near the nematic transition temperature. We show that it can be well explained by the Landau theory for the second-order phase transitions considering that the external field is not zero. The effect of the coupling between the isotropic and nematic channels is shown to be negligible. Moreover, our results suggest that the nature of the magnetic and nematic transitions in Sr_{1 − x}Ba_xFe₂As₂ is determined by the strength of the magnetic-elastic coupling. (paper)

[en] This study investigated the transformation of triclosan (TCS) following co-exposure to UV irradiation and ClO₂. Special attention was given to understand the influencing of water quality parameters and toxicity changes during the co-exposure process. The results show that the co-exposure process prompted TCS elimination quickly and effectively, with more than 99% of TCS degraded under the experimental conditions. The molar yield ratios of 2,4-dichlorophenol/TCS (2,4-DCP/TCS) were calculated to be 35.81–74.49%; however, the by-product of 2,8-dichlorodibenzop-dioxin (2,8-Cl₂DD) was not detected. The TCS degradation was sensitive to ClO₂ dosage, pH, H₂O₂, and natural organic matter (NOM), but not to the carbonate (CO₃²⁻) concentration. Neutral and slightly alkaline condition were favorable to TCS elimination. The TCS removal rate increased from 85.33 to 99.75% when the ClO₂ concentration increased from 0.25 to 1.5 mg L⁻¹. TCS degradation can be promoted at low NOM level (1, 3, and 5 mg L⁻¹), whereas was inhibited at high NOM concentrations of 7 and 9 mg L⁻¹. While adding H₂O₂, the degradation rate of TCS increased with increasing H₂O₂ concentration from 1 to 3 mg L⁻¹; however, too low or overdosed H₂O₂ (0.5 and 5 mg L⁻¹) hindered TCS degradation. Based on the results of a microtox bioassay, the toxicity did not change following the co-exposure process.