Advanced Materials Research Vols. 860-863

Abstract: Lanthanum hexaaluminates LaAl12O19-δ modified by transition-metal ion (Mn, Co and Ni ) were prepared through co-precipitation of metal nitrates within the water phase of a Triton X-100/n-hexanol/cyclohexane reverse microemulsion. The effects of different modification ion and the precursor solution concentration on the catalytic property of catalysts were investigated. The structure and properties of these samples were characterized by XRD, BET, SEM and TG-DTA. The stabilities of catalysts were assessed by measuring the activities for combustion of methane. Upon calcination at 1200°C, when the precursor solution concentration is 0.75M, the sample LaMnNiAl₁₀O_19-δ retained a specific surface area of 40.34m²/g and showed a excellent activity for methane combustion, which temperature at 10% , 90% and 99% conversion were 420 °C, 690 °C and 760 °C, respectively.

Abstract: This paper introduces the characteristics and application of polybutylene terephthalate, and then focus on the researches to remove its disadvantages. On this basis, we discuss the influence of different modification methods on the properties of polybutylene terephthalate, and the prospect of the modification has been described as well.

Abstract: Phase change materials in the form of emulsion (PCE) is a category of novel phase change fluid used as heat storage and transfer media. It plays an important role in commercially viable applications (energy storage, particularly).The emulsion is made of microparticles of a phase change wax (a kind of paraffin or mixture ) as a phase change material (PCM), mixed paraffin directly with water. This paper presents information on the different PCM emulsions by different researchers. It gives the method of preparation of the PCE, and makes a special effort to investigate the heat transfer phenomena and the method of enhancing the thermal conductivity of the emulsion.

Abstract: Based on the experimental results of transmittance, particle swarm optimization (PSO) algorithm was adopted to establish inverse research model to calculate the refractive index and absorption index of nanofluids, we used the inverse calculation model to calculate the refractive index and absorption index of water and aqueous nanofluids, comparing inverse calculation results with experimental results, it turned out that inverse calculation model can accurately calculate the refractive index and absorption index of nanofluids.

Abstract: The ANSYS finite element techniques were used for modeling and analysis of piezoelectric materials. The single piezoelectric sheet model was presented. The basic characteristic of the piezoelectric materials were analyzed and the affecting factors of characteristics were derived. The high frequency simulation results showed that the displacement responses of piezoelectric materials were very large delay in boost and buck under the high frequency voltage signal, and that was adverse to the vibration control. The low frequency voltage simulation results showed that the displacement response frequency and voltage signal frequency were exactly the same. The model thickness greatly affected its stiffness and indirectly affected its output characteristics.

Abstract: Li-rich layered xLi₂MnO₃-(1-x) LiMO₂(M=Ni,Co,Mn...) solid solution materials possess high energy density, high capacity, and long cycle life. Meanwhile, the electrochemical charge/discharge mechanism is quite different. In this paper, Li-rich cathode material xLi₂MnO₃-(1-x) LiMO₂(M=Ni,Co,Mn...) is introduced though its structure, charge/discharge mechanism, synthetic methods and electrochemical performance. What is more, the characteristics and development trend of this series of cathode material are summarized.

Abstract: MgO-Al₂O₃-SiO₂ ceramics were recently explored as infrared radiance materials to provide an environmental friendly energy candidate for industrial heating and drying. Cu ferrite was selected to dope MgO-Al₂O₃-SiO₂ ceramics, forming a series of composite ceramics via solid-state reaction method to enhance the infrared radiation properties. The phase identification and morphologies of the samples were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. The infrared emissivity was examined by Fourier transform infrared (FTIR) spectrometer. The results showed that an improvement of infrared radiation properties can be achieved by doping Cu ferrite in MgO-Al₂O₃-SiO₂ ceramics. With increasing the dopant content from 0 wt % to 10.0 wt %, the crystallization behavior changed accordingly. A positive correlation was found between the infrared emissivity and the lattice strain. The highest infrared emissivity (0.91±0.01) was obtained after sintering at 1150 °C for 2 h with Cu ferrite content was 7.5 wt %, in which the maximum lattice strain (0.282 %) occurred. MgO-Al₂O₃-SiO₂ ceramics doped with Cu ferrite have potential for the application of infrared heating and drying fields.

Abstract: Cathode material LiNi_0.5Mn_1.5O₄ was synthesized via oxalate co-precipitation process using LiCl,NiCl₂·6H₂O and MnCl₂·4H₂O as raw materials, oxalate as precipitant. The effects of calcining temperature and polymer-assisted during the synthetic process on the performance of the products were analyzed. When calcining at 700°C for 10h and with assistance of polyacrylic acid as dispersive, the synthesized product had cubic spinel structure, uniform particle size and the aggregations of particle was reduced.

Abstract: Ge epilayers on low temperature (LT) Ge buffer layers were grown by ultrahigh vacuum chemical vapor deposition using the two-step approach. Effects of the growth temperature and the thickness of the low temperature Ge buffers were studied. It was demonstrated that it was unable to obtain flat LT Ge buffers just through lowering the growth temperature due to the ultraslow grow rate that 3D islands formation couldnt be prohibited. However, the rough LT Ge surface was smoothed by subsequent growth at elevated temperature if the LT Ge layer was thick enough and the compressive strain was relaxed largely, and the detrimental Si-Ge intermixing was effectively prohibited as well. When using proper growth conditions for the low temperature Ge buffer, thick Ge epilayer with a low threading dislocation density and a smooth surface was obtained.

Abstract: In order to analyze the ageing mechanism of oil-paper, the Atomic Force Microscope (AFM), which is one of the important instruments in nanometer area, was used in this paper for the analysis of the micro surface morphology, and a 3-D surface roughness analysis on the AFM image was presented. The AFM figures indicates that the molecular arrangement of the initial cellulose paper is close and ordered, some of the hexagonal mesh structures of the D-glucopyranose units were broken down after 100 days accelerated thermal ageing. The roughness analysis indicates that he fiber surface roughness parameter Sa increases with the deepening of ageing degree. Special attention should be paid on the increase in the surface roughness of insulation paper, as it will aggravate the oil streaming electrification when the paper is applied to the power transformers.