Abstract: ZnO will become a new pattern optoelectronic material because of its many excellent properties. But the defects in ZnO crystal are the key factors for restricting the luminescence properties of the material. In this paper, we summarized the defect types that exist in ZnO thin films and reviewed on the relationship between the luminescence mechanism and the structure defects of ZnO thin films reported in recent years.
Abstract: Porous spheres of TiO2 nanoparticles have been successfully prepared using cationic monomer as precursory solid and thermal decomposition at 500 oC. The product was characterized by X-ray powder diffraction and scanning electron microscope. The ultraviolet photocatalytic activity of the obtained materials was evaluated by decomposing 1-naphthylamine-4-azobenzene-4'-sulfonic acid. The porous spheric TiO2 exhibited a good photocatalytic activity. The degradation rate was about 96.5% for in contaminated water after 50 min irradiation by UV light.
Abstract: In this study, Al2O3–13 wt% TiO2 ceramic powders was perset on the substrate of a GH416 Ni-base superalloy by the squash presetting method and cladding coatings were fabricated by a fiber laser. Influences of substrate preheating on the microstructure and interface characterization of laser-clad ceramic coatings were investigated. The results show that the crack formation of the clad ceramic coating can be prevented by substrate preheating. In addition, substrate preheating is helpful to form a good metallurgical bonding between the coating and substrate. Clad ceramic coatings with dense structures, crack-free, low dilutions and good metallurgical bonding to substrate were obtained under the optimum processing parameters. The cross-section of the clad coating indicated three different microstructural regions, namely, fine equiaxed crystals at the upper region, columnar crystals in the middle region, and very fine equiaxed crystals at the bottom region.
Abstract: In this study, Ni60/Ni-WC composite coatings were first prepared by plasma spraying. Then, the coatings were remelted successively with a CO2 laser. The influences of laser power on the microstructural characterization and microhardness of the coatings were investigated. The results show that the defects of as-sprayed coating like lamellar stacking microstructure and pores were eliminated by laser remelting, and the remelted coating possessed a denser microstructure. With the increase of the laser power, the burning loss and dissolve of the WC particles is increased, while the dilution rate of the coating becomes large. The laser-remelted samples had higher hardness than the as-sprayed one. Laser power has a great impact on the coating and an optimized process parameter is helpful to achieve appropriate melting of WC particles, which leads to retain a high proportion of hard phase in the coating, good combination between the WC particles and Ni-base matrix alloy, and high microhardness.
Abstract: nanoAg island thin films with different thickness have been prepared by vacuum vapor deposition method on ITO substrates for organic solar cells. UV-Vis absorption spectrum and surface morphology have been studied by UV-Vis scanning spectrophotometer and SEM. The influence of different thickness nanoAg has also been discussed. The results show that, when the nanoAg thickness is 3.0 nm, the surface plasmon response is most obvious, the resonance absorption peak appears red-shift, the surface plasmon response could enhance optical absorption, photocurrent, fill factor and power conversion efficiency obviously. The research results provide theoretical guidance to optimize the design and increase the performance of solar cells.
Abstract: N-doped Cu2O (Cu2O:N) thin films were deposited on glass substrate by reactive pulse magnetron sputtering method using Cu target in a mixture of N2、O2 and Ar atmosphere. Effect of substrate temperature on structure, surface morphology and optical properties of thin films were investigated by XRD, AFM and UV-Vis spectroscopy. The results showed that the single-phase of Cu2O(111) thin films were grown for substrate temperature < 200°C. The thin films deposited under different substrate temperatures are characteristics of 2D growth. Moreover,the optical band gap Eg of thin film was in the range 2.54-2.58eV, and slightly decreased with increasing of substrate temperatures from RT to 400°C.
Abstract: Co-doped Fe2O3 oxygen carriers reacted with CO were investigated in order to study the temperature effect on the redox characterization.Co-Fe2O3 were characterized with X-ray diffraction (XRD), BET and transmission electron microscope (TEM), which showed that the surface structure was regular, and the polymorph was stable. The TG (Thermo Gravimetric Analyzer) analysis indicted that, rational doping Co could enhance the reactivity of iron-base oxygen carrier reacted with CO under different conditions. Oxygen carrier with Fe: Co molar ratio of 1:0.1 had best reactivity. With the temperature increased, the reduction degree became deeper and the complete conversion time shortened. The reduction reaction Co0.1Fe oxygen carrier with CO was carried out step by step, and the entire process was divided into three stages, namely 344.7-391.0, 414.7-472.5 and 607.6-681.5°C.
Abstract: The hydrogen residued process of the High-strength steel surface during the phosphorization process was studied. By the hydrogen permeation experiment, that penetration speed of the hydrogen residued in the metal surface were measured. The result of shows:the more hydrogen gas generated in the process of phosphorization,the more hydrogen atom inside the metal. That means the hydrogen embrittlement criticality of the High-strength steel were more fearful。Dense phosphorizing film always block hydrogen atoms to penetrate into the metal,So that cuold to reduce the hydrogen embrittlement extend of the steel in phosphorization.
Abstract: The microscopic deformation mechanism was taken into account to research the high efficient solid ice and snow clearing technology. The solid ice and snow constitutive model was established, which the deformation mechanism of snow microstructure and macroscopic continuous behavior were linked together, considering the damage of solid ice and snow depends on the mechanical properties of the snow volume elements of the grain bonds between grains, and using the microstructure factor scale the stress state of microstructure in the continuous stress. The density is 520Kg/m3-600Kg/m3 of the solid ice and snow was selected for studying and the homogeneous triaxial loading test was conducted by using the SJ-1A strain control type triaxial shear instrument. The relations of local strain rate with limit stress was established according to the simulation analysis conducted the constitutive model that was been established, the results found that both of those showed a near-linear relations, it was fit with the experience relations. The computer simulation and experimental curves deviated a little, and the reasonableness of the established solid ice and snow constitutive model was verified. Studied have shown that the failure rule of solid ice and snow can be well described by the constitutive model, which presents a theoretical reference for the design of key icebreaking components.