Advanced Materials Research Vols. 418-420

Abstract: Nanocomposite fibers are one of the most fascinating materials with broad applications. In the present work，nanocomposite fibers were prepared by a low-cost, simple, and “green” process. The nanocomposite of cellulose acetate/TiO₂ was realized by combining the functional oxide material TiO₂ with the regenerating electrospun cellulose acetate fibers. The structural features were characterized by scan electron microcopy, transmission electron microscopy and infrared spectrum. The compositing mechanism was proposed. The surface functionalized hydroxyl by the regenerating process plays an important role for the formation of hybrid material.

Abstract: A systematic study of the cladding NiTi alloy on 2Cr13 stainless steel by plused Nd-YAG laser has been conducted. The geometry and microstructure of the clad layer are studied by optical microscopy and scanning electron microscope, respectively. The phase composition of cladding layer is analyzed by X-ray diffraction, and its hardness distribution along the depth of the clad layer is measured by microhardness tester. The results show that, with the augmentation of current, the height of clad layer decreases but that the width and clad angle increase. Three typical microstructures (B2 phase+tetragonal structure of precipitates, dendrites and grains) are precipitated in the NiTi alloy during rapid solidification. The average microhardness of the clad layer in C-2, C-4 and C-5 samples are about 670HV, 700HV and 615HV, respectively.

Abstract: Through the weight loss experiment in 3.5%NaCl solution, the effect of Ce contents on the corrosion resistance of AZ91 magnesium alloy was carried out. In addition, the damping performance of Ce added AZ91 alloys were also studied. The result shows that adding Ce can significantly improve the corrosion resistance and damping capacity of AZ91 magnesium alloy; the grain refinement and secondary phase morphology modification can contribute to those properties improvement.

Abstract: Recycled aggregate concrete technology has been payed widely attention. In addition to the research on the basic performance of recycled aggregate concrete, the impact resistance performance of recycled aggregate concrete was also involved. Through mixing respectively steel fiber, polypropylene fiber and steel-polypropylene hybrid fiber into the recycled aggregate concrete, the writer studied the impact resistance performance of fiber-reinforced recycled aggregate concrete, and compared the influence of reinforced fiber on the impact resistance performance of recycled aggregate concrete.

Abstract: Biodiesel is one of the most promising alternative clean fuels to fossil fuel, which can effectively reduce the emissions from fossil fuel burning. The high oxygen content in biodiesel can promote the burning process, but it can also increase NOx formation simultaneously, when biodiesel is used as fuel. Fuel emulsification is considered to be effective in reducing NOx emissions. In this study, soybean oil was used as raw oil to produce biodiesel by transesterification reaction. The biodiesel product was then emulsified with water and emulsifying surfactant to form water-in-oil (w/o) biodiesel emulsion. The biodiesel emulsion composed of 1.5% polyoxyethylated castor oil (EL-12), 0.7% lethicin and 0.5% cetylpyridinium chloride (CPC) was proved to have the better emulsifying activity (EA) and emulsifying stability (ES) values, and higher combustion heat than those of the neat biodiesel and reference biodiesel emulsion (with 2.7% EL-12 as the emulsifying surfactant).

Abstract: With the rapidly developing of our country's economy, the demand of diesel fuel is increasing. But the fuel resource is limited. Because diesel fuel's incomplete combustion can pollute environment, it is getting more and more attention of people. The current problems of saving energy and reducing consumption needed to resolve, especially diesel particulate after combustion emissions are gasoline 30 to 70 times. The environmental pollution caused by automobile exhaust already quite serious, in this new clean diesel exploring alternative fuels is imperative, the research of this aspect has also been the world attention. A bench test of 490QB diesel engine was conducted with self-developed heavy aromatic fuel mixture of coal. Road test proves that using heavy aromatic fuel mixture of coal on diesel fuel can save fuel. The power performance of heavy aromatic fuel mixture of coal was equivalent, and fuel consumption decreased and smoke emissions reduced obviously compared with common diesel fuels.

Abstract: Microstructure evolution of a nickel-base single crystal superalloy on the [001], [011] and [111] orientation during thermal exposure at 1000°C was investigated. The SEM studies revealed that the size of γ' phase increased and some of which linked together with the elongation of the exposure time. After 1100h the cubic γ' phase hardly is observed, and the rafting structure becomes perfect. With growing and linking of γ' phase the γ matrix channel is widening gradually, and the direction of γ' rafts is not along one define orientation. The TCP phase is not found in the three oriented samples during the thermal exposure.

Abstract: In this study, digital treatment method was developed in order to reconstruction of the 3D CAD of hemp fibre geometry. The influence of each aging condition (moisture, heat and UV aging) on the mechanical properties of hemp fiber is investigated by micro tensile tests. Different hemp fibre morphologies was presented and discussed. The results showed a high impact of the hemp fibre morphology on their mechanical properties (Young modulus, maximum stress and failure strain). The influence of aging conditions on the mechanical properties of hemp fibers is also investigated.

Abstract: A new white-light long afterglow phosphor Sr₂SiO₄: Pr³⁺ was synthesized by solid-state reaction, the influence of preparing conditions on the luminous property of Sr₂SiO₄: Pr³⁺ were studied, and characterized by X-ray diffractometer, fluorescence spectrophotometer and thermo luminescence(TL) meter. The results indicated that the emission spectra of phosphor is composed of bluish purple (390nm), green(535nm)and red(604nm)light emission, and the sample prepared at 1473K, heat treatment time for 4h, 0.5mol% Pr³⁺ and 1mol% flux H3BO3 conditions shows the best property.

Abstract: Pure and Sm substituted BiFeO3 nanoparticles were prepared by a coprecipitate method using Bi(NO₃)₃•5H₂O and Fe(NO₃)•9H₂O as raw materials. X-ray diffraction pattern indicates that perovskite structural BiFeO₃ can be obtained using 0.02 molar precursor precipitate by annealing at 550 °C. A structural phase transition deduced by Sm substitution was observed. SEM results showed that the size of BiFeO3 increases with annealing temperature and substitution ratio. DTA results showed that the phase transformation temperature decreases with Sm substitution ratio.