Advanced Materials Research Vol. 1035

Abstract: A novel approach to assemble the (12S)-12-Hydroxymonocerin’s core skeleton was developed in 29% overall yield, in which a three component Linchpin coupling, stereocontrolled reduction and an intramolecular Friedel-Crafts/Marson cyclization were utilized as key steps.

Abstract: In this paper, we studied the different content of aramid fiber, aramid pulp, carbon fiber, high silica fiber, mullite fiber, alumina fiber's effect on EPDM inhibitor material. The result show that aramid fiber can significantly improve the ablation resistance of thermal insulation layer, when the content of aramid fiber up to 6.7%,the inhibitor material's ablating rate get the minimum value 0.04mm/s. Aramid pulp can improve ablation resistance of thermal insulation layer, but its dispersion in insulation material is difficult. Others inorganic fiber can't lower the ablating rate as much as aramid fiber, it mainly because of the brittleness of inorganic fiber, during the dispersion process, most of fiber had been triturated, so those fiber can't decrease the liner ablation rate of the inhibitor.

Abstract: Rubber products of different thickness have a significant difference of aging degree in mechanical properties due to varied environmental impact from surface to center. Previous study of performance degradation and life prediction methods did not pay enough attention to this problem. In this paper, a quantitative analysis is conducted, and a relationship between properties of different depth (given by a 40 years indoor natural aging experiment) and material overall properties is built to observe mechanical properties changing and evaluate aging life of different thickness of rubber. The result shows an obvious difference in mechanical properties and aging life, which seems should be considered when conduct an aging experiment and life evaluation.

Abstract: As a new technique to form sheet metal parts, Multi-point forming (MPF) also can be used on bending aluminum alloy profile. Since the Multi-Point Die (MPD) which replaces the traditional solid bending die is composed of many discrete punch elements, dimples always occur on the plate of profiles. To eliminate the dimpling defects, numerical simulation of the bending process with A6N01S-T5 aluminum alloy hollow profile using MPD were conducted. By comparing the bending effects on MPD with different size of punch elements and with different kind of elastic cushion, reasonable forming parameters were obtained. Pressing of Aluminum alloy profile with different radii on the MPD and solid die were simulated. The cross-section distortion indicated that the aluminum alloy profile can be formed with MPF technique while it has the advantage of flexibility. For the profile with large deformation, multi-step MPF method is a better choice due to its rapid reconfigurable characteristic.

Abstract: In order to overcome the occurrence of insufficient oxidation reaction, high temperature oxidation resistance (ZrB₂-SiC)/Si composite coating was fabricated on the surface of graphite electrode by argon arc cladding, process using the Si, Zr and B₄C power blends. The microstructure and phase composition of the clad layer were researched by means of scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The result shows that the coating consist of ZrB₂ and SiC particles, The combination of the cladding layer and the graphite matrix results in kind of a continuous interface without visible defects. As the result of burning 60 min at 1573K, the oxidation weightlessness rate is 0.62%.

Abstract: In this paper, the effect of elevated temperature on the behavior of carbon fiber-reinforced T300/BMP350 unidirectional laminates was studied by loading static tensile on 0°, 90°and ±45° lay-up. The stress-strain relationships of the laminates under different temperatures were obtained. The effect of temperature on the mechanical properties of materials was systematically studied. The damage and failure mechanisms of the material were studied by analyzing the material stress-strain curves and the failure modes. Results show that the T300/BMP350 polyimide matrix composites have a strong resistance to high temperature. For 0° and 90° lay-up, the retentions of tensile strength and modulus are more than 80% and 50%, respectively. High temperature has little effect on the material failure modes. Finally, based on the test results, an empirical formula which relates strength and temperature of the material was fitted.

Abstract: Joining process and mechanical properties of clinched joints in Al5052 aluminum alloy sheets had been studied in this study. The clinched joints were classified to round one and rectangle one. Results of cross-section showed that the minimum thickness of the rectangle joints were lower than the round joints, and the aspect ratio of undercut section corresponding was larger. The strength of rectangular joint was 1.7 times of round one. Failure mode of rounded joint was the upper sheet fractures at the neck having a minimum thickness, but failure mode was the mix of neck-fracture and pulled-out for rectangular joint.

Abstract: This work reports copolymerization of ethylene-propylene (EP) using a novel phenoxy–ester ligated titanium catalyst. Copolymerization reactions were conducted in toluene at 70 ^°C with varied E/P flow ratios. Fourier transform infrared spectroscopy, X-ray diffractometer, nuclear magnetic resonance spectroscopy and differential scanning calorimetry analysis were performed to characterize the structures, compositions and glass transition temperatures of the copolymers. The results show that ethylene-propylene copolymers are random polymers and the link ratios of ethylene to propylene are between 0.89 and 1.26. The glass transition temperature of ethylene-propylene copolymer is-43.3 °C.

Abstract: Sr₃Ti₂O₇ ceramics with pure Ruddlesden-Popper phase (RP) were synthesized by conventional solid state method. The influences of the Bi₂O₃ addition, the calcination temperature, and the sintering temperature on the phase transition were studied. The results showed that for the samples without doping Bi₂O₃, the main phase of calcined powders is Sr₃Ti₂O₇, but pure Sr₃Ti₂O₇ phase cannot be obtained in the sintered ceramics because of the Sr₃Ti₂O₇ decomposition. For the samples doping with Bi₂O₃, although the main phase of the calcined powder is SrTiO₃, the single RP phase Sr₃Ti₂O₇ can be obtained after sintering, which should be attributed to the formation of Sr₃Bi₂O₆ phase during calcination stage. Bi₂O₃ addition is beneficial to the formation of the Sr₃Ti₂O₇ RP phase.

Abstract: In corrosive soils areasand extremely cold regions,high performance is required inthe impermeability and frost resistanceof concrete poles. In this paper, the mix design of C60 high performance concrete and the relationship between mix parameters and performance is studied and analyzed ,and the influence of the water-cement ratio, the amount of cementation materials, the mineral admixtures and other factors on High Performance Concrete is discussed, as well as the impact of different admixtures for concrete. According to the analysis results, the concrete mix is designed and used in practice.