No abstract available

No abstract available

[en] Impact toughness of a gas tungsten arc welded Ti-6Al-4V alloy butt-joint was evaluated at room temperature using standard Charpy V-notch specimens. The Charpy specimens were prepared with notch roots located either in the parent metal, in the heat-affected zone (HAZ), or in the weld metal. Optical metallography and Vickers microhardness test showed that the weld metal has the coarsest grains and highest microhardness compared with the HAZs and parent metal. However, Charpy impact toughness of the weld was found to be more than 50% higher than that of the parent metal or HAZ. The significant improvement in impact toughness was shown to be due to the much reduced amount of primary α grains in the weld metal. Boundaries of primary α grains were observed to be preferential sites for microcrack nucleation and provide relatively easy path for fracture propagation

[en] Highlights: • An in situ method is developed for immobilization of nanoscale LDHs. • The universal method can be applied on multiple substrates. • The homogeneous LDHs film can be synthesis and immobilized in one step. • The LDHs film showed good adsorption performance towards anionic compounds. - Abstract: Preparation and immobilization of layered double hydroxides (LDHs) film onto multiple substrates is important and challenging in functional materials fields by date. In this work, a simple and universal polydopamine (PD)-based layer-by-layer assembly strategy was developed for the immobilization of LDHs film onto surfaces such as polypropylene chip, glass slides and metal coins. The surface of substrates was firstly modified by polydopamine functionalization, and then LDHs film was synthesized via urea method and directly immobilized on the PD layer by in situ growing strategy in one step. The PD layer as well as the final LDHs film was characterized by energy dispersive X-ray spectroscopy, scanning electron microscope, infrared spectroscopy, X-ray diffraction pattern and X-ray photoelectron spectra. It has been demonstrated the formation of the dense and homogeneous nanoscaled LDHs film with 400 nm thickness. Adsorption behavior of the fabricated NiAl-LDHs film toward anionic dyes and pharmaceuticals was further assessed. To demonstrate their extensive application, fast and high efficient adsorption of anionic dyes and pharmaceuticals was achieved by NiAl-LDHs-modified polypropylene centrifugal tube.

[en] Highlights: • A systematical investigation has been carried out on Zn_1_−_xAl_xO system. • Our results confirm that Zn_1_−_xAl_xO nanoparticles are magnetic. • The magnetism originates from charge transfer between different cations. • The accordant conclusion is drawn both theoretically and experimentally. • The ferromagnetism would render it to realize more comprehensive applications. - Abstract: The mechanism of ferromagnetism in Al-doped ZnO was investigated both theoretically and experimentally. The density functional theory calculations were carried out to explore the electronic structure origin of ferromagnetism. The Al dopants both doping in a bulk ZnO and absorbing on the ZnO surface are taken into account. Based on the Bader charge analysis for the clear and adsorbed ZnO surface, it is found that the ionic state of Zn decreases after Al doping. The corresponding room temperature ferromagnetism was also confirmed by experiments. Moreover, the experimental analysis rules out that the ferromagnetism results from zinc vacancy or oxygen vacancy. Thus, the physical origin of the induced magnetism was indicated originating from the charge transfer between Zn atoms and adsorbed Al atoms

[en] Here we explore the effect of charge-compensated donor-acceptor pairs (2Nb + C), (2Ta + C), (Mo + 2N) and (W + 2N) codoping on the electronic and optical properties of TiO_2 nanosheets. The results demonstrate that the (2Nb + C) and (2Ta + C) codoping create the delocalized midgap states in TiO_2 nanosheets. The appearance of impurity states extends the absorption edge of nanosheets to the visible light region. The interaction of the host and the foreign chiefly occurs at the band edges of the N-related systems, which reduces the band-gap by 0.5 eV. Although this large band-gap still renders the visible light inefficient, the enhanced UV light absorption has been observed. Besides, the position of absorption edge is independent on the doping concentration, but the higher codoping concentration yields stronger light absorption. Moreover, the band edge alignment verifies that the C-related systems are desirable visible and UV-light-driven photocatalysts for overall water splitting. - Highlights: • A systematical study has been employed on 2D TiO_2 nanosheets with the donor-acceptor codoping. • The (2Nb/2Ta + C) codoping in TiO_2 nanosheets creates the delocalized midgap states. • The C-related systems are desirable visible and UV-light-driven photocatalysts. • The water splitting power of (Mo/W + 2N) codoped systems is improved with enhanced UV light response. • The high doping concentration means the stronger absorption ability of the solar energy.

[en] A computer code COMPASS based on compartment model approach is developed to calculate the near-field source term of the High-Level-Waste repository under unsaturated conditions. COMPASS is applied to evaluate the expected performance of Richard's (capillary) barriers as backfills to divert infiltrating groundwater at Yucca Mountain. Comparing the release rates of four typical nuclides with and without the Richard's barrier, it is shown that the Richard's barrier significantly decreases the peak release rates from the Engineered-Barrier-System (EBS) into the host rock

[en] Highlights: • Polycrystalline SnNx films were fabricated by reactive sputtering. • The film has a hexagonal tin-rich structure with the band-gap of ∼3.10 eV. • The conductivity of the films shows metallic-like behavior. • The origin of magnetism may be from the unpaired spin electrons. • Grain boundaries and thermal decomposition also influence the magnetic and transport properties. - Abstract: Polycrystalline SnN_x films were fabricated by reactive sputtering with various substrate temperatures. The film has a hexagonal tin-rich structure and decomposition temperature is above 500 °C. The band-gap enlarged to 3.10 eV due to the complex defects and the conductivity of the films shows metallic-like behavior, which has the opposite variation trend with ferromagnetism as the substrate temperature changes. The origin of ferromagnetism may be from the intrinsic point defects, which result in a net moment by unpaired spin electrons. The feeble coercivity with no obvious magnetocrystalline anisotropy suggests that the magnetism in our samples is not a bulk effect, and it distributes unevenly in the grain boundaries or interfaces. Furthermore, thermal decomposition also has significant influence on the magnetic and transport properties

[en] Highlights: • The band gap widening is observed in Li-doped SnO₂ films. • All the films are ferromagnetic and the largest saturation magnetization of 7.9 emu/cm³ has been observed in Sn_0.88Mg_0.12O₂film. • The holes induced by Li replacing Sn enhance the magnetism. • The p–p interaction between the 2p states of the O atom is responsible for the long-range ferromagnetic order. - Abstract: Epitaxial grown Li doped SnO₂ films with room temperature d⁰ ferromagnetism were prepared by radio frequency magnetron sputtering. X-ray diffraction and X-ray photoelectron spectroscopy give clear evidence of Li presence at both substitutional and interstitial sites. A conversion of conductivity from n-type to p-type was observed as the Li concentration reaches 6 at.%. The band gap of films increased non-montonically with the Li concentration. All the films are ferromagnetic, and the largest saturation magnetization of 7.9 emu/cm³ is observed in the Sn_0.88Li_0.12O₂ film which has the widest band gap. The consistency of the variation between the magnetic, structural, electrical and optical properties indicates that holes introduced by Li substitutions can enhance the ferromagnetism though p–p interaction

[en] Structures, optical and magnetic properties of epitaxial Sn_1−xK_xO₂ films were investigated experimentally. Three distinct symmetry equivalent in-plane orientations were observed between the film and substrate. The ferromagnetism enhances monotonously with doping and the largest saturation magnetization is 7.88 emu/cm³ in Sn_0.92K_0.08O₂ film. Generated K interstitials may give rise to a symmetry-lowering distortion of the surrounding lattice. The alignment of magnetic moments in Sn_1−xK_xO₂ films is established through p–p coupling interaction between the impurity p states and host p states. The lattice distortion induced by K at both interstitial site and substitution site will disturb the arrangement of the electrons and can be remitted by post-thermal treatment. - Highlights: • (100)-orientated Sn_1−xK_xO₂ films were deposited on the (0001) surface of sapphire. • Three distinct symmetry equivalent in-plane orientations were observed. • The ferromagnetism enhances monotonously with doping, which is established through p–p coupling interaction. • The lattice distortion will disturb the arrangement of the electrons and can be remitted by post-thermal treatment