[en] According to characteristic of nuclear industry and the requirement of welding, a program of novel inverted welding power supply has been designed. Adopting IGBT as inverted switch component, the switch on and switch off are controlled by the PWM. The width of pulses is controlled by using the current output errors in pallered with the peak current of the switch elements. The experiment indicated such power supply remains stable, which attains the need of design. (authors)

[en] Highlights: • Ag_3PO_4 photocatalysts were synthesized via one-step and two-step ion-exchange reaction. • Photocatalytic properties of Ag_3PO_4 photocatalysts was investigated, the result indicated the Ag_3PO_4 (2) was higher than that of Ag_3PO_4 (1) under the same experimental condition. • Ag_3PO_4 (2) particles were larger than Ag_3PO_4 (1) particles and many polygonal-shaped surfaces could be clearly observed in the Ag_3PO_4 (2) particles. - Abstract: Ag_3PO_4 photocatalysts were prepared via two and one-step through a facile ion-exchange route. The photocatalysts were then characterized through powder X-ray diffraction, scanning electron microscopy and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of the samples was evaluated on the basis of the photocatalytic degradation of methyl orange (MO) and methylene blue (MB) under solar irradiation. The MO degradation rate of the Photocatalyst synthesized by the two-step ion-exchange route was 89.18% in 60 min. This value was four times that of the Photocatalyst synthesized by the one-step approach.The MB degradation rate was 97% in 40 min. After six cycling runs were completed, the MO degradation rate was 73%

[en] The adsorption properties of H₂ on LiF molecule under an external electric field are studied by using DFT method. The results show that H₂ can form weak physical adsorption on the Li or F atom. However, the external electric field can enhance the adsorption energy of single H₂ on the Li/F from -0.112/-0.122 eV without an electric field to -0.122/-0.171 eV with the field intensity of 0.005 a.u., respectively. It is more stable when H₂ is adsorbed on F atom. The mechanism of electric field enhancing the adsorption of H₂ on LiF is also explored through the quantum theory of atoms in molecules (QTAIM). The results reveal that the electric field not only promotes the charge transfer between LiF and H₂, but also makes LiF and H₂ polarized, and thus improves the adsorption. Under the electric field, the LiF molecule can adsorb ten H₂ molecules at most, and the corresponding mass density of hydrogen storage reaches to 43.5 wt %. Our results suggest that the LiF-based materials adsorbed H2 under an external electric field is a potential method for hydrogen storage. (authors)

[en] Highlights: • Tremella-like porous SnO₂ Microsphere and its CNTs hybrids are first constructed controllably under microwave radiation. • They express superior lithium storage performances as anode materials. • SnO₂-S/CNTs hybrids remain 470.16 mAhg^–1 after 550 cycles at the current density of 1.0 Ag^–1. • Synergistic effects on morphologies, structures and properties for both SnO₂-S and SnO₂-S/CNTs are illustrated. -- Abstract: To improve the electrochemical performance of SnO₂-based electrode materials, a simple and efficient method was developed for constructing porous SnO₂ microsphere (p-SnO₂ MS) and its carbon nanotube hybrids (p-SnO₂ MS/CNTs), for the first time, by only changing solvent kinds under microwave-radiation conditions. After their microstructures and electrochemical properties were investigated, it is noted to find that the proposed p-SnO₂ MS assembled by nano plates is mainly composed of rutile phase with a little orthorhombic phase. Among all single SnO₂ materials with different morphologies, p-SnO₂ MS displays a charge capacity of 860.59 mAhg^–1 after 50 cycles, and a charge capacity of 593.37 mAhg^–1 at the current density of 4.0 Ag^–1. Once hybridized with CNTs, the corresponding charge capacity of p-SnO₂ MS/CNTs would improve to 926.58 mAhg^–1 and 625.50 mAhg^–1 respectively under the same conditions. Importantly, p-SnO₂ MS/CNTs could deliver quite a stable charge capacity of 478.53 mAhg^–1 after 600 cycles at 1.0 Ag^–1 in Li/p-SnO₂ MS/CNTs half cells and a high specific capacity of 738.03 mAhg^–1 after 100 cycles in p-SnO₂ MS/CNTs/LiNi_0.5Co_0.2Mn_0.3O₂ full cells. The relationship between micro-structure and improved electrochemical performance is investigated in detail for both p-SnO₂ MS and p-SnO₂ MS/CNTs. This work will offer a promising insight into constructing some practical anode materials with improved lithium storage performances.

[en] Spherical porous Al₂O₃ nanoparticles were synthesized by hydrothermal method using C₆H₅(NH₄)₃O₇·2H₂O and Al(NO₃)₃·9H₂O as raw materials. The morphology and size of the Al₂O₃ particles were significantly influenced by hydrothermal temperature, time, and the molar ratio of Al³⁺ to (C₆H₅O₇)³⁻. The interphase Al(OH)₃ is a key factor on the preparation of γ-Al₂O₃. Under the hydrothermal conditions of high temperatures, Al(OH)₃ decomposes into the precursor γ-AlOOH instead of the exothermic reaction between Al(OH)₃ and H⁺. In the form of hydrogen bonds, (C₆H₅O₇)³⁻ adsorbs on the surface of γ-AlOOH nanoparticles to form some nano-chains, which interweave and tangle each other to become spheres. During calcination, the precursor γ-AlOOH converts to γ-Al₂O₃ nanoparticles while the spherical morphology is retained. Gas outrush during calcination should be the formative cause of the porous structure. The as-prepared spherical porous Al₂O₃ nanoparticles can be used as a catalyst or carrier due to the favorable adsorption property. (paper)

[en] Highlights: • Fine-grained Cu(70-90)-W composites were successfully fabricated by sintering nano-scale CuW powders at different temperatures. • The CuW composite sintering process is ascribed to the sintering interactions that occur both within each powder and between the powders. • The spherical and nano-sized tungsten particles were evenly embedded in the copper matrix and CuW interface had a semi-coherent relation. • The effect of the sintering temperature on the properties of CuW composites had been analyzed. -- Abstract: Fine-grained Cu(70–90%)-W composites were successfully produced using nano-scale CuW powders in vacuum condition. The sintering process of CuW composites is ascribed to the sintering interactions that occur both within the powders and between the powders. Microstructure analysis of the CuW composites showed that the big spherical and nano-sized tungsten particles were evenly embedded in the copper matrix. The CuW interface had a semi-coherent relation and displayed good contact. The relative density, hardness, electrical conductivity and W crystal size in the CuW composites increased when the sintering temperature rose from 1000 °C to 1090 °C. With elevating copper content, the hardness and the tungsten grain size of CuW composites were found to decrease, but the relative density and electrical conductivity improved. The relation of the electro-conductivity, sintering temperature, and W crystal size of the CuW composites was described with a regression formula.