[en] Ag-coated C₆₀ nanoclusters were prepared and characterized with X-ray diffraction, transmission electron microscopy and nitrogen adsorption–desorption isotherm measurement. The Ag-coated C₆₀ nanoclusters were assembled on the glass substrate to form a thin film using the layer-by-layer technique. Meanwhile, the surface enhanced Raman scattering (SERS) of musk xylene adsorbed on the film of Ag-coated C₆₀ nanoclusters was explored. The results indicated that the film of Ag-coated C₆₀ nanoclusters was a unique SERS-active substrate with a detection limit of 10⁻⁹ mol L⁻¹ for musk xylene. Furthermore, the surface enhanced mechanisms were discussed preliminarily.

[en] Objective: To explore the role of PI3K/Akt/COX-2 pathway in the radiation resistance of human cervical cancer HeLa cells. Methods: The HeLa cells were cultured in vitro. Using Celecoxib in Hela cells or associated with LY294002 for 24 h, the cells were radiated by different doses of X-ray. The cell survival ratio was detected by clone formation. To calculate D_q , D₀, SF₂, SER, the cell survival curve was draw by one-hit multitarget model. The expression of pAkt, Akt, COX-2, Bad and pBad were detected by Western blot. The mRNA expression of COX-2 and Bad was detected by RT-PCR. Results: The D_q, D₀, S_F2 of Celecoxib or associated with LY294002 group was lower than those in radiation group. The pathway PI3K/Akt/COX-2 was activated by irradiation. Celecoxib inhibited the activation of PI3K/Akt/COX-2 for multitarget. Conclusions: The activation of PI3K/Akt/COX-2 signal transduction resulted in resistance of radiosensitization in HeLa cell. It was indicated that inhibiting PI3K/Akt/COX-2 pathway could improve the radiosensitivity of human cervical cancer HeLa cells. (authors)

[en] Systematic studies on polycrystalline Eu²⁺-Β^-alumina including sample preparation, microstructure, ionic conductivity and thermal stability are reported. (author). 9 refs.; 4 figs.; 2 tabs

[en] Magnetic mirror used as an efficient tool to confine plasma has been widely adopted in many different areas especially in recent cusped field thrusters. In order to check the influence of magnetic mirror effect on the plasma distribution in a cusped field thruster, three different radii of the discharge channel (6 mm, 4 mm, and 2 mm) in a cusped field thruster are investigated by using Particle-in-Cell Plus Monte Carlo (PIC-MCC) simulated method, under the condition of a fixed axial length of the discharge channel and the same operating parameters. It is found that magnetic cusps inside the small radius discharge channel cannot confine electrons very well. Thus, the electric field is hard to establish. With the reduction of the discharge channel’s diameter, more electrons will escape from cusps to the centerline area near the anode due to a lower magnetic mirror ratio. Meanwhile, the leak width of the cusped magnetic field will increase at the cusp. By increasing the magnetic field strength in a small radius model of a cusped field thruster, the negative effect caused by the weak magnetic mirror effect can be partially compensated. Therefore, according to engineering design, the increase of magnetic field strength can contribute to obtaining a good performance, when the radial distance between the magnets and the inner surface of the discharge channel is relatively big. (paper)

[en] Recently the (G'/G)-expansion method was proposed to find the traveling wave solutions of nonlinear evolution equations. This paper shows that the (G'/G)-expansion method is a special form of the truncated Painlevé expansion method by introducing an intermediate expansion method. Then the generalized (G'/G)–(G/G') expansion method is naturally derived from the standpoint of the nonstandard truncated Painlevé expansion. The application of the generalized method to the mKdV equation shows that it extends the range of exact solutions obtained by using the (G'/G)-expansion method

[en] The Ga₂O₃/ZnO multilayer films are deposited on quartz substrates by magnetron sputtering, the thickness values of Ga₂O₃ layers are in a range of 19 nm–2.5 nm and the thickness of ZnO layer is a constant of 1 nm. Formation of spinel ZnGa₂O₄ film is achieved via the annealing of the Ga₂O₃/ZnO multilayer film. The influences of original Ga₂O₃ sublayer thickness on the optical and structural properties of Ga₂O₃/ZnO multilayer films and annealed films are studied. With the decrease of the thickness of Ga₂O₃ sublayer, the optical band-gap of Ga₂O₃/ZnO multilayer film decreases, the intensity of UV emission diminishes and the intensity of violet emission increases. The annealed film displays the enlarged optical band gap and the quenched violet emission. UV fluorescence bands are observed from Ga₂O₃ and ZnGa₂O₄. (interdisciplinary physics and related areas of science and technology)

[en] Based on first-principles plane-wave calculations, we firstly reconfirm that the Li+graphene complex can be taken as a hydrogen storage medium with capacity of 12.8wt%. Then metal adsorption properties of this Li+graphene system with different charge states are investigated. Finally, the hydrogen storage ability of the charging system is calculated. Our calculations show that adding positive charge on a Li+graphene composite results in a conspicuous reduction of Li2s and Li2p orbital occupation with respect to the C2p state. As a result, a stronger bonding between Li and graphene is formed, and a special double-layer hydrogen adsorption structure has been found. Compared to the neutral system, utilizing the positive charged Li+graphene to store hydrogen molecules can solve the issue of clustering of metal atoms after releasing hydrogen, and can improve hydrogen storage capacity up to a gravimetric density of 20.4wt%, correspondingly one adsorbed Li atom can effectively absorb up to seven H₂ molecules

[en] In this article, a new type of superimposing morphology comprised of a periodic nanostructure and a random structure is proposed for the first time to enhance the light scattering in silicon-based thin film solar cells. According to the framework of the Reyleigh—Sommerfeld diffraction algorithm and the experimental results of random morphologies, we analyze the light-scattering properties of four superimposing morphologies and compare them with the individual morphologies in detail. The results indicate that the superimposing morphology can offer a better light trapping capacity, owing to the coexistence of the random scattering mechanism and the periodic scattering mechanism. Its scattering property will be dominated by the individual nanostructures whose geometrical features play the leading role. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

[en] Phosphorene, a 2D material, holds great promise for applications in optoelectronics and gas adsorption. The electronic structure and gas adsorption ability of phosphorene doped with three noble metal atoms (Ag, Au, Pt) are simulated by first-principles calculations based on density functional theory (DFT). Our DFT calculations reveal that doped phosphorene has low formation energies (or high adsorption energies). Doping also tailor the band gap of phosphorene, and cause the electronic properties to change. NO and CO molecules are physisorbed on both pristine and doped phosphorene, visible through their high adsorption energies and charge transfer values. Pt doped structure shows the highest adsorption energy for NO and CO molecules. The results are highly helpful to design gas sensors based on Pt doped phosphorene. (paper)

[en] This research develops a simple template assisted sol-gel process for preparing porous TiO₂ for a high performance humidity sensor. Tetraethyl orthosilicate (TEOS) as a template was directly introduced into TiO₂ sol formed by the hydrolysis and condensation of titanium alkoxide; the following calcination led to the formation of TiO₂-SiO₂ composite, and the selective removal of SiO₂ by dilute HF solution led to the formation of porous structure in TiO₂. The resulting porous TiO₂-based sensor exhibits high sensitivity and linear response in the wide relative humidity (RH) range of 11%-95%, with an impedance variation of four orders of magnitude to humidity change. Moreover, it exhibits a rapid and highly reversible response characterized by a very small hysteresis of < 1% RH and a short response-recovery time (5 s for adsorption and 8 s for desorption), and a 30-day stability test also confirms its long-term stability. Compared with pure TiO₂ prepared by the conventional sol-gel method, our product shows remarkably improved performance and good prospect for a high performance humidity sensor. The complex impedance spectra were used to elucidate its humidity sensing mechanism in detail.