Advanced Materials Research Vols. 287-290

Abstract: Influence of Nd₂O₃ on structure and dielectric property of zirconia barium titanate has been investigated by means of XRD、SEM、EDXS. The results show that Nd₂O₃ will accelerate the grain growth if increasing the Nd₂O₃ amount and improve the sintering of the materials；Nd₂O₃ distributes mainly at the grain boundary in the materials and has influence on the anti-corrosion of grain surface; it will be helpful to increase the dielectric constant of the materials by increasing amount of Nd₂O₃ in the materials, but the resistivity will decrease.

Abstract: Jet electrodeposition orientated by rapid fabrication were introduced , The nanocrystalline nickel parts were fabricated using jet electrodeposition . The microstructure and phase transformation of nanocrystalline nickel were observed under the scanning microscope and X-ray diffraction instrument . The results show that the jet electrodeposition can greatly enhance the limited current density, fine crystalline particles and improve deposition quality. The nickel parts prepared by jet electrodeposition own a fine-grained structure with a smooth surface and high dimensional accuracy under the optimum processing parameters.

Abstract: Ionic liquid based on imidazolium cation; 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMITFSI) has been incorporated with epoxidized natural rubber-50 (ENR-50) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) to obtain electrolyte material. Fourier transform infrared spectroscopy (FTIR) spectra showed evidence of complexation between ENR-50, EMITFSI and LiTFSI. Glass transition temperature, T_g displayed an increasing trend with increase in salt concentration. The incorporation of EMITFSI resulted in an increase in ionic conductivity. The increase in ionic conductivity was attributed to the role of ionic liquid which reduced T_g, thus, facilitated ion conduction in the system. The highest ionic conductivity at room temperature was 5.72 ´ 10^-4 S cm^-1 for sample containing 20 wt% of EMITFSI and 50 wt% of LiTFSI.

Abstract: According to the features of heavy horizontal directional drill hydraulic system, power head hydraulic system which is the main working mechanism of the 280t horizontal directional drilling is modeled and simulated base on Amesim. On that basis, we adjust working characteristics of this model and make the point of view that feedback control parameters which is the hydraulic system of heavy drill should be adjusted according to the soil conditions. So that it can enhance the utilization rate of the machine power and drilling efficiency in different operating modes.

Abstract: Fly ash/LLDPE composite material was obtained by using the molten blending. The melting, crystallization and thermal degradation of fly ash/LLDPE blends were investigated. The results indicate that the addition of fly ash increases the molten peak of blends, which shows that fly ash has the function to prevent heat transfer. The addition of the powder of fly ash has prevented the regular spread of LLDPE molecue and has impact on the regular spread when the segmer crystallizes, spreads and moves, which slows LLDPE's crystallization rate, and has an inhibitory action to LLDPE crystalloid's growth; the starting degradation tempreture (T0, 5%weight loss ) of complex system is lower than that of pure LLDPE, but the tempreture at maximum egradation rate increases with the quantity of fly ash increasing.

Abstract: This paper describes the calculation analysis of joint open, and the research has been carried up on Portland cement concrete pavement and rubberized concrete pavement with the consideration of hogging distortion caused by temperature, expansion deformation and drying shrinkage. Finally ,it were observed that joint open of 6m contraction joint spacing for rubberized concrete pavement is the same as 4.5m contraction joint spacing for Portland cement concrete pavement. The above analysis provides the possibility of 6-meter contraction joint spacing for rubberized concrete pavement which give theoretical basis for engineering application.

Abstract: The effects of ultrasonic and Baumé degree of Ca(OH)₂ suspension on the size of nano-CaCO₃ prepared by carbonization were studied. The results indicated that ultrasonic could improve the dispersibility of powder, reduce the aggregation and decrease the particle size of nanometer calcium carbonate. The fine particles synthesized at 40 kHz were smaller but rougher than that obtained at 20 kHz. The frequency hardly influenced the morphology of nanometer calcium carbonate. Moreover, the lower Baumé degree of Ca(OH)₂ suspension was adopted, the smaller the size of nano-CaCO₃ were obtained. And in the process of carbonation, we were using SEM and XRD to study the nucleation and growth mechanism, it indicated that amorphous calcium carbonate particles acted as nuclei in the initial stage oriented absorption calcium hydroxide to form wirelike substances. In the end, these botryoidal shape crystals were disaggregated into calcium carbonate with the particle diameters of 30nm.

Abstract: Nanometer-sized β-SiC were synthesized by carbothermal reduction of silica sol with acetylene carbon black at 1600 °C for 2h. Three kinds (straight, bamboo-like, branch-like) of SiC nanowires were deposited on the graphite plate, while SiC particle agglomerates and nanowires were formed in the graphite crucible. All the nanowires were formed via VS mechanism through the reaction between gaseous SiO and CO produced from the process of carbothermal reduction.

Abstract: This intends to examine the flexural behavioral characteristics of hybrid UHPC using a mix of steel fibers with different lengths. Three types of fibers are adopted with fixed diameter of 0.2 mm and lengths of 13, 16.3 and 19.5 mm (aspect ratio of 65, 82 and 98, respectively). Comparative analysis of the flexural strength, load bearing capacity, deflection and toughness is performed adopting a mix use of these 3 types of steel fibers with ratio of 2% and 1.5%. The results show that the hybrid use of steel fibers improves significantly the flexural strength and flexural toughness compared to the use of a single type of fiber. When steel fibers with lengths of 16.3 mm and 19.5mm are admixed at a rate of 1% each, UHPC develops a flexural strength larger by 27% (maximum 50%) than conventional UHPC admixed with 2% of steel fiber with length of 13 mm. Moreover, flexural strength similar to that of conventional UHPC is secured when steel fibers with lengths of 16.3 mm and 19.5mm are admixed at respective rates of 0.5% and 1% (total rate of 1.5%).

Abstract: In this paper, electron beam radiation technology was applied to the preparation of MMT/MWNTs/epoxy nano-composites. The influences of the addition of Montmorillonite (MMT) and multi-walled carbon nanotubes (MWNTs) on the tensile properties of MMT/MWNTs/epoxy nano-composites were examined. The fracture surface of the composites was characterized by SEM as well. The results indicated that the composites have higher tensile modulus than that of the pristine epoxy resin.