Advanced Materials Research Vol. 771

Abstract: The preparation of graphite oxide is one of essential steps for graphene by oxidation reduction method. Graphite oxide was acquired from the oxidation of graphite by improved Hummers method and characterized by X-ray diffraction, scanning electron microscope, Fourier transform infrared absorbance spectroscopy and thermogravimetric analysis. It was showed that the graphite interlayer distance of graphite oxide increased for a large amount of oxygen containing functional groups. Shift and broaden of diffraction peaks were observed after oxidation and the original graphite peaks disappeared.

Abstract: We demonstrate the existence of a hidden degree of freedom controlling the orbitalordering in [LaTiO1/[LaAlO5 multilayers with comprehensive density-functional theorycalculations. The orbitals of two-dimensional (2D) 3d¹ state of Ti atoms in the multilayers alwayscontain large dxy components, which is unexpected from crystal field theory (first Jahn-Tellerdistortion). The competition between first and second Jahn-Teller distortion induces variousmagnetic properties. Thus, transition-metal oxides/non-transition-metal oxides multilayers mayprovide an important direction to manipulate the spin and orbital ordering in magnetic materials.

Abstract: We report a new type of biochemical materialmultifunctional paclitaxel-loaded poly lactide-lecithin (PLA-lecithin) microbubbles which has been developed with a method of ultrasonic double emulsion solvent evaporation (UDES) combined with lyophilization. Bubbles were characterized to be hollow, well dispersed andwith size of 300nm~2um. Paclitaxel loading efficiency could reach up to 12%, and bubbles with different size and different lecithin content showed varied drug release characteristics but all displayed slow-release and ultrasound controlled properties, illustrating the ultrasound responsive drug release effect of the combination of microbubbles and ultrasound.

Abstract: The output current of the current-source inverter (CSI) can be very steady. It is applied in the circumstance when precise current is needed. But the output characteristic of CSI depends on not only its performance but also the batterys nature. This paper presented a practical judge model which can simulate the batterys output threshold. In a simulation system, the amplitude of inverting current can be a very large value provided the loop impedance is small enough and the output current can remain steady. But in actual operation CSI has its out put limitation. When the given current is big, the output current will be unsteady. It is very risky because it might cause short circuit between both sides power. The output characteristic of CSI is studied from the mechanism when the control block generate the trigger impulse. The reason why the output values differ greatly between simulation and test is discussed. The simulation used a method by adopting a concussion judgment module to detect the CSIs output state. The reference currents the amplitude information and phase information is separated. The proportion between reactive component and active component is concerned to regulate CSIs output current. Simulations and tests proved the correctness and feasibility of the method.

Abstract: Isothermal oxidation behavior was investigated for Ni-20Cr alloy with addition of different Ce 0 (wt)%, 0.042(wt)% and 0.094(wt)% at 1150°C for 100h.The surface and cross-section microstructures of the oxide scales were analyzed by EPMA(Eelectron Probe Micro-Analysis). The addition of Ce in Ni-20Cr alloy may improved the cohesion between the matrix and the oxide scales significantly and increased the oxidation resistance of Ni-20Cr alloy. Compared with 0 (wt)%Ce and 0.042(wt)% Ce in Ni-20Cr alloys, the oxide scales on Ni-20Cr alloy with addition of 0.094(wt)% Ce showed compact, which limited the internal oxidation.The cross-section microstructure of oxide scales presented three complicated oxide layers, which were Cr₂O₃, SiO₂ and Al₂O₃ from the oxide scales to the matrix.

Abstract: This paper studies the effect of water-cement ratio [w/ on the air-void parameters of cement concrete, which has a significant influence on the durability of concrete. Based on the experimental investigation, it is found that the impact on the air content of hardened concrete due to different water-cement ratio is not great. Test results also indicate that with the increase of water-cement ratio, the spacing factors also experienced a marked rise, and the mean diameters as well as the specific areas of air voids evidently increased or declined, respectively, which may lead to an adverse effect on the frost resistance of concrete.

Abstract: To improve adhesion strength of DLC coatings on 304 stainless steel substrate,we studied substrate pretreatment by electrolytic/chemical etching methods.In this study,The DLC coatings were deposited on two groups of 304 stainless steel which had been electrolytically and chemically etched separately. The morphology of the coatings and substrate were characterized by SEM and metalloscope. The surface roughness of substrate was measured by roughness tester .The result shows that adhesion strength of DLC coatings on 304 stainless steel substrate is improved obviously due to mechanical interlock,surface adsorption and stress release.With prolonging the etching time,the adhesion strength of DLC coatings on the chemically etched substrate increase firstly and then decrease. The adhesion strength of DLC coatings on electrolytically etched substrate continuously increase. DLC coatings on electrolytically etched substrate perform better than the one on chemically etched substrate in adhesion.This is caused by the different surface morphology.

Abstract: Polysaccharides from Tussilago farfara L.(TFPs) was extracted with the assistance of ultrasonic.Box-Behnken design (BBD) was employed to optimize extraction time; extraction temperature;ultrasonic extraction power and ratio of water to raw material to obtain a high TFPs yield.The optimum extraction conditions were as follows: extraction temperature 65.1°C, ultrasonic power 380.5W, extraction time 28.7 min and ratio of water to raw material 23.6ml/g.The yield of polysaccharide was 2.14% based on the above mentioned conditions.

Abstract: The environmental safety of 2,2,4,4-tetrabromodiphenyl ether (BDE-47), a widely used flame retardant, has been the topic of controversial discussions during the past decade years. In this study, we investigated the BDE-47 degradation by a novel bacteria obtained from electronic waste recycling site soil sample in Taizhou, China. Using biochemical characteristics and 16S rDNA gene sequencing, the strain was closely related to Bacillus sp. with a 99% 16S rDNA gene sequence similarity. It could use BDE-47 as the sole carbon source and energy source for its growth. The optimal growth environment was in the presence of BDE-47 at concentrations to 50-200 ug/L, pH 6.0 to 8.0 and 37°C when agitated at 160 rpm. For the initial concentrations of 100 ug/L, 50% of the BDE-47 was degraded. This is the first report of BDE47-degrading strain from the genus of Bacillus sp. under aerobic condition.