Advanced Materials Research Vols. 152-153

Abstract: The effect of the temperature at the friction surface on spheroidization and refinement of Si particles in hypereutectic Al-30Si alloys was investigated. Al-Si samples as cast were first preheated to 15°C, 100 °C, 300 °C and 500 °C, respectively, then rubbed against a steel counterface for 5 min under a normal pressure of 50N. Refined layers where all the Si particles were broken to 0.71-0.87μm in diameter and spheroidized simultaneously to 0.69-0.74 in shape factor were found in the friction surface of the samples. As the preheating temperature increased, the refinement effect was gradually weakened, and the spheroidization effect was enhanced. The reason of the simultaneous spheroidization and refinement were discussed.

Abstract: In this paper, the flame-retardant synergistic effect between rare earth oxide and conventional flame retardants (aluminum hydroxide and iron trioxide) has been studied using vertical combustion test. The results show that good flame-retardant synergistic effect exists between them. The composites combining 100 grams of aluminum hydroxide, 40 grams of iron trioxide and 0.8 grams of rare earth oxide can reach FV-0 in vertical combustion test. The thermal stability influence of rare earth oxide to silicone rubber has also been studied by means of thermogravimetric analysis. It has been found that rare earth oxide can function as thermal stabilizer in silicone rubber.

Abstract: Utilizing the higher order decoupling approximation to the Fermi-type Green’s function, crossover properties of interaction parameters of an n-layer ferroelectric thin film from the ferroelectric-dominant phase diagram (FPD) to the paraelectric-dominant phase diagram (PPD) are investigated on the basis of the transverse Ising model. The curved surfaces for crossover values of interaction parameters of a thin film with certain layers are constructed in the three-dimensional parameter space. Because both the z-component (the polarization) and the transverse component of the spin are further included in the eigenfrequency, the results are in agreement with that of the effective-field theory with correlations to some extent. It shows that the higher order decoupling approximation diminishes the ferroelectric feature of a ferroelectric thin film compared with the usual mean-field approximation.

Abstract: M-type BaFe12O19 nanocrystalline aggregations were prepared by the citrate sol-gel method, using Fe(NO3)3 and Ba(NO3)2 as raw materials, urea and ethanol as the soft template. The samples were investigated by SEM, TEM, FT-IR, XRD and VSM. SEM and TEM micrographs show the product is hollow nanocrystalline aggregations with microporous. XRD patterns indicate M-type BaFe12O19 aggregations with mesoporous are purity and well crystallinity, the average size of the primary crystals of the aggregations is 48nm. Saturation magnetization and coercivity of the aggregations is 55.3emu/g and 5403Oe, respectively, which are higher than these of previous BaFe12O19 nano-particles reported in the literature.

Abstract: 35 steel was processed in order to investigate its structure and performance after strengthened shot peening and gas tufftriding process. The composition,structure and phase of the samples were analyzed by means of scanning electron micrograph(SEM),metallographic microscope and X-ray diffraction(XRD)respectively. The results show that the hardness of samples after strengthened shot peening increases by about 100 HV0.025,and the friction coefficient and corrosion rate decrease.However,the samples treated with gas tufftriding after strengthened shot peening exhibit the performance of approximate 3 times hardness of the original samples, lower friction coefficient,more excellent tribological characteristics,stronger corrosion-resistance with a stable and broad passivation region.

Abstract: In this article, konjac flour, super absorptive resin and pellet urea were added into flexible polyurethane foamed plastic with polyether polyol and isocyanate as the raw materials by a new water-foamed technology to manufacture a kind of absorptive and biodegraded polyurethane foamed fertilizer. Polyurethane foam was used as a carrier material and konjac flour was used as a biodegradable agent. The results showed that the slow-release velocity of urea could be controlled by regulating the densities of polyurethane foams, the content of konjac flour and super absorptive resin. The carrier material could be degraded konjac flour by naturally.

Abstract: Fe-doped TiO2 was prepared by a homogenous precipitation method and characterized by XRD, UV-Vis DRS. The structure and the optical properties of nano-TiO2 with different Fe doping content were studied, as well as the effect and the possible mechanics of different intensity of TiO2 particles, Fe-doped nano-TiO2 particles on the activity of HL60 leukemic cells. The influence on the activity of cells exposures in light compared with un-exposure also be analysed. As the photo sensitizers, TiO2 and Fe-doped TiO2 particles eliminated tumor cell using photodynamic therapy(PDT)under magnetic field.

Abstract: Two two-dimensional and three-dimensional coordination-polymer, [Ni(2,2′,5,5′-bpdc) (H2O)]•H2O (1) and[Ni(2,2′,6,6′-bpdc)2]•4H2O (2) were obtained via hydrothermal reaction between NiCl2•6H2O and 2,2′-bipyridine-5,5′-dicarboxylic acid (2,2′,5,5′-bpdc), 2,2′-bipyridine-6,6′-dicarboxylic acid (2,2′,6,6′-bpdc) respectively, and were characterized by infrared spectra, thermogravimetric analysis and single crystal X-ray diffraction. The 2,2′,5,5′-bpdc and 2,2′,6,6′-bpdc ligands in compound 1 and 2 show different coordination modes respectively. The 2,2′,5,5′-bpdc ligand acts as pentadentate connector to coordinate with three different Ni(II) ions, and further extend to form square grid framework of compound 1; while 2,2′,6,6′-bpdc acts as tridentate ligand to chelate one Ni(II) ion to construct discrete monomeric unit, and those discrete units of [Ni(2,2′6,6′-bpdc)2]•4H2O are joined into 3-D framework via rich hydrogen bonding interactions. Thermogravimetric analysis revealed that both complex (1) and (2) display considerable thermal stability. CCDC 773845 & 773846.

Abstract: This paper reports performance date for the direct methanol fuel cell (DMFC) with membrane electrode assemblies using modified poly (vinylidene fluoride) grafted the blended polystyrene sulfonated acid membranes (m-PVDF-g-PSSA) based on modified PVDF (poly vinylidene fluoride ) and the bended PSSA (polystyrene sulphonated acid). The membrane exhibited low methanol permeation coefficient, and good proton-conductivity. Furthermore, these materials have potentially lower methanol cross-over when compared to standard Nafion-type membranes. The membranes electrode assemblies were based on Nafion®-bonded carbon-supported catalyst: platinum/ruthenium for the anode and platinum for the cathode. The catalyst layer was coated directly on the treated membrane. To simulate the practical application, unit cell operates at room temperature and ambient pressure using liquid methanol and ambient air. A methanol solution is filled in the feed reservoir, and the cathode is exposed to ambient air. The cell performance of the self-breathing air DMFC, for short duration (<100h) testing, with the low cost membranes is superior to that of cells based on Nafion under identical operating conditions.

Abstract: The structural properties of camshaft were affected by many factors such as pouring temperature and inoculation which were studied in this paper. The results showed that with the increase of the pouring temperature, the chilled depth and hardness decrease. However, at a very low pouring temperature, the cooling velocity was fast and the formation of dissociative carbonide precipitate was easily; even the whole cam may become white iron, so the optimal pouring temperature is 1375 -1450 . Moreover, when the bearing location of camshaft is less than 15% carbonide, reducing the inoculants contents may cause the graphite amount decreasing, and the improvement of chilled hardness. While, reducing the amount of inoculants can improve the chilled sensibility of molten metal, which is favorable for production control. The experimental results showed that the optimum adding content is no more than 0.3% Si-Ba.