Advanced Materials Research Vols. 581-582

Abstract: By macroscopic observation, metallographic examination, scanning electron microscope and energy spectrum analysis, it is inferred that the steel flow bellows SEN is too strong that the heat delivering at steel top surface in the mould is not enough by taking sample on slab, F2 transition strip and hot strip steel with cracks, which causes insufficient mould powder melting, and hooked oscillation marks are formed. Since liquid steel liquidity is not good either, a part of powder can be caught by solidification front, and many fine cracks are generated on slab surface. This kind of hooked oscillation mark, subsurface fine crack and corner crack evolve into edge crack, and rolling simulation testing proved this inference. Moreover, Cu beneficiation is also one reason of edge crack. Edge crack of hot strip steel study can be used to guide actual production, and to avoid the generation of edge crack.

Abstract: Quaternary Ti-Si-C-N films were deposited Si wafer by middle frequency magnetron sputtering Ti80Si20 twin-targets in mixture atmosphere of Ar, CH4 and N2. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) results indicate that the films present an amorphous structure with no columnar structure. These films are quite uniform and dense without large particles. The film deposited at 10 sccm CH4 and 10 sccm N2 flow rates exhibits a maximum hardness of 18.9 GPa and high elastic recovery of 97%.

Abstract: CuO nanorod arrays, networks of nanosheets and pistachio nuts consisting nanorods were prepared via a multi-step synthesis method starting from copper oxalate precursor. CuO nanorod arrays were prepared by solid state thermal calcination of Cu(OH)2 nanorod arrays through the reaction of copper oxalate precursor with NaOH at 40°C. CuO networks of nanosheets were obtained by treatment at 60°C for 90min, and CuO pistachio nuts consisting nanorods were obtained at 80°C for 20min. The products were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM).The influences of temperature and reaction time on the synthesis of CuO were investigated. The formation mechanism of CuO nanostructures was discussed.

Abstract: Al₂O₃/NiAl composites were successfully fabricated by hot-press-assisted exothermic dispersion method with elemental powder mixtures of Ni, Al, NiO. The content of Al₂O₃ on the microstructures and mechanical properties of Al₂O₃/NiAl composites has been characterized. The results show that the Vickers hardness, flexural strength and fracture toughness of the composites increase with increasing Al₂O₃ content. When the Al₂O₃ content is 15 wt %, the flexural strength and the fracture toughness peaked at 765 MPa and 9.67 MPa•m ^1/2, respectively. The improvement of mechanical properties is associated with a more homogeneous and finer microstructure developed by addition of Al₂O₃.

Abstract: The influence of the pretreatment polyester short fiber on the mechanical process and the properties of the NR/ SBR compound was studied by using contrast method. The results showed that the maximum power and the unit energy consumption increased because of short fiber, and the temperature also enhanced. So the low rotate speed is better. When the composite were cured, it had much characteristic such as rapid vulcanization speed, short scorch time and vulcanization smooth period. But the mechanical properties were increased. In the end, the microscopic photo of composite with the scanning electronic micrograph was taken.

Abstract: study the effect of different levels of aluminum (1.5%, 2.0%, 2.5%, 3.0%, 3.5%), nickel (0.6%, 0.8%, 1.0%), cobalt (0.2%, 0.4%, 0.6%), yttrium (0.01%, 0.03%, 0.05%) on the characteristics and structure of Cu-22.7Zn brass as-cast. The results show that all above elements added can refine brass grains on extent, change the size of phase, and improve the brass hardness, tensile strength and corrosion resistance. When the content is 3.5% in the alloy, the hardness of brass increases to 78.7HRB, up 6% compare with Cu-22.7Zn brass. With 1.0% Ni, the strength of the alloy raises to 76.5 HRB, increased by 3.6%. Cu-22.7Zn-3.4Al as-cast alloy, its strength of alloy increases 12.5% with 0.6% Co, and enhances 9.8% with 0.03% Y.

Abstract: The mesoporous carbon material is prepared by using phenolic resin and MgO nanoparticles as precursor and template, respecitively. The microstructure of the carbon is characterized by N2 adsorption/desorption, Hg porosimetry and field-emission scanning electron microscopy(SEM). The electrochemical performances of the carbon as anode material for lithium ion batteries are evaluated by galvanostatic charge/discharge and cyclic voltammetry tests. It is shown that the BET surface area of the mesoporous carbon material can reach 1024 m2/g. Its pore size distributes between 20 and 50nm. The mesoporous carbon possesses high first discharge capacity and good cycling performance. It is believed that it is an effective method to use nano-MgO particle as template to prepare mesoporous carbon anode materials for lithium ion batteries.

Abstract: Lithium-ion battery cathode materials, Li3V2(PO4)3/C, were prepared via rheological phase method. Li2CO3、NH4H2PO4、V2O5 were employed as raw materials, and citric acid or polyethylene glycol (PEG) was used as the chelating agent (carbon source). The structure, morphology characters and the electrochemical performances of the samples were tested. The results show that modification by carbon-coating is favorable for the growth of particles. The primary particle size obviously decreases with PEG added, while the agglomeration of primary particles could be inhibited using the citric acid as carbon source, which makes particle size more uniform. Moreover, the electrochemical test results show that both the two kinds of carbon sources can effectively improve the specific capacity and the cycling performance compared with the uncoated sample.

Abstract: The LiFe0.98Ni0.01Nb0.01PO4/C was synthesized by carbon reduction route using FePO4•2H2O as precursor. The LiFe0.98Ni0.01Nb0.01PO4/C sample was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical measurements. The XRD analysis, SEM and TEM images show that sample has the good crystal structure, morphology and carbon coating. The charge-discharge tests demonstrate that the powder has the better electrochemical properties, with an initial discharge capacity of 164.6 mAh•g−1 at current density of 0.1 C. The capacity retention reaches 99.8% after 100 cycles at 0.1C.

Abstract: Hypocrellin A is organic dyes with more superior visible light performance, which has resistant tumor activity and becomes widely accepted. In this paper, acetone is used as solvent to extract, separate and purify the hypocrellin A. With ZnCl2 and Na2S as raw material, ZnS Quantum dots (QDs) were prepared by water-phase synthesis method under the role of the magnetic stirrer. Fluorescence detection results showed that the optimum pH of the ZnS QDs and HA solution close to neutral (6.86). The fluorescence quenching of hypocrellin A is most obvious as the ZnS QDs was added, because of the strong interaction was generated between HA and ZnS QDs, resulting in the fluorescence quenching.