Advanced Materials Research Vols. 189-193

Abstract: In order to improve wear resistance of engine cylinder, the surface hardening technology is analyzed. The hardening methods which iron plating and composite iron plating have application in engine cylinder repair are put forward. The relative speed and pressure between piston ring and cylinder wall are determined as main wear factors of engine cylinder. And wear resistance of hardening material is chosen as assessment index. At the high load, the relative wear resistance of engine cylinder hardened by composite iron plating is twice as high as high phosphors cast iron. By comprehensive contrast of the wear resistance of hardening materials, relative wear resistance of composite iron plating is better than common engine cylinder material, and can fit for the cylinder hardening of high load engine.

Abstract: The relationship between the groove structure of the direct current plane electromagnetic pump and efficiency has been investigated in this paper. Methods By using mercury as working medium, experiments have been conducted through simulation of direct current plane electromagnetic pump. The comparision of efficiencies is obtained by measuring the values of hydrostatic head of various groove structures under the fixed working parameters are measured. The groove structure of the electromagnetic pump has a great influence on its hydrostatic head and its relative efficiency. Several important ways can be used to improve the efficiency of the electromagnetic pump including restraining the overflow of working current, optimizing the direction of the electrolines, reducing the inner surface area of the groove and increasing the entrance force.

Abstract: The resistivity of samples made with different shaping technology or dispersers have been measured, and researched the dispersiveness of carbon fibers. It is observed that the resistivity of the hybrid fiber cement-matrix composites could be improved greatly by adding disperser and adopting rational shaping technology.

Abstract: A gas quenching process to deal with steel slag and its characteristics of the new technology was briefly introduced. The grinding characteristics, mineral phases of gas quenching steel slag and the potential economic benefits of using it as cement mixing material was studied by compared to heat-stew steel slag. The results indicated that the specific surface areas (S) and grinding times (t) of the gas quenching steel slag showed a first order exponential decay relationship. With the extension of time, the specific surface areas of heat-stew steel slag was tending to balance earlier than that of gas quenching steel slag; The energy consumption of gas quenching steel slag was much lower than that of heat-stew steel slag. Gas quenching steel slag was comprised of C₂S, C₃S, a certain amount of (Ca₂(Al, Fe)₂O₅）and RO phase, but the content of RO phase was relatively low, which increased the grindability of the quenching steel slag, so that the grindability of gas quenching steel slag was much better than that of heat-stew steel slag. Gas quenching steel slag prepared for cement addictives would bring great economic benefits.

Abstract: Nozzle is an important component of the spray equipment, the thesis using the theoretical knowledge of fluid to calculate the nozzle’s size to design the nozzle, and also using the stress analysis module of the ANSYS software to analyze the stress to choose the optimal nozzle structure.

Abstract: Ni-doped Na_0.5Bi_0.5TiO₃ crystals were synthesized and studied by X-ray diffraction (XRD), X-ray spectroscopy (EDS), and magnetic property measurement system (MPMS). Room-temperature ferromagnetism has been observed in Ni-doped Na_0.5Bi_0.5TiO₃ crystals. It was found that the magnetism of NBT crystals can be controlled by Ni doping concentration. The magnetism of the Ni-doped Na_0.5Bi_0.5TiO₃ crystals develops from diamagnetism to ferromagnetism and paramagnetism on increasing Ni doping concentration from 0 to 1.25mol %. The results presented in this study may provide an approach to widely exploring more multiferroic materials.

Abstract: The precipitation behavior of the second phase particles was observed and studied by a carbon extraction replica technique used transmission electron microscopy (TEM) for Nb-bearing dual-phase steel. It is found that there are more second phase particles on the surface than that of in the center of sample. The mainly smaller particle which sizes of is below 20nm show the shape of spherical and ellipse. The sizes of larger particles are range of 20nm~40nm and the shape of them present rectangle or ellipse. The particles are dispersed on the matrix and the particle boundary is clear. The precipitate composition of particles are all Nb(C、N) examined by energy dispersive X-ray (EDX). The results of microstructure shows that the second phase particles pinned on grain boundary not only can inhibited the grain growth, but also the grain can be fined during the heating and cooling course.

Abstract: The characteristics of the 1045 steel pairs using superfine mineral powder as grease lubricant additive were investigated by an AMSLER friction and wear tester at different wear states. The surface topographies and composition of the worn surface of 1045 steel rings were identified by SEM and EDAX. The surface roughness of the samples was investigated by a profilometer. The results show that the additives can form a self-repairing film on the worn metal surface at Sliding state and there no film formed on the worn metal surface at Rolling-Sliding state. The reason is that the friction heat and friction energy produced by Sliding friction higher than the friction heat and friction energy produced by Rolling-Sliding friction.

Abstract: Wearability of polyester textile is very outstanding in chemical fabric；silkworm pupae protein has good biocompatibility. In order to make a new kind of polyester textile which not only has good wearability, but also has good biocompatibility, the polyester fibers were semi-encased with sucrose ester to endue polyester fibers with reacting hydroxyl groups, and then silkworm pupae protein was grafted on surface of polyester fiber textile with a crosslinkage compound in this study. The structure of polyester textile grafted with silkworm pupae protein were studied by SEM, X-ray diffraction and differential scanning calorimetry(DSC). The polyester fibers were enclosed by layer of materials in SEM, X-ray diffraction showed silkworm pupae protein was random coil conformation, DSC exhibited the thermal property of polyester fibers almost did not change. The wearability of polyester fabric grafted silkworm pupae protein was measured too. With the increase of grafting silkworm pupae protein rate on polyester fabric, moisture permeability of polyester fabric increased firstly and decreased a little subsequently, the moister regain increased monotonously, the cockle elasticity decreased a little, the whiteness almost did not change, and flexural stiffness increased a little.

Abstract: In the thermal design of Embedded Power Chip Microwave Modules, the placement of chips on substrate has a significant effect on internal temperature field, thus, influence the reliability of the modules. In this paper, Based on BP-GA, the optimization for chips placement of EPCM is achieved by corresponding optimization program. To demonstrate the effectiveness of the results, ANSYS, finite element analysis (FEA) is carried out to assess the thermal field distribution of the optimization for chips placement. The result shows that the thermal field distributions of the optimization are consistent with the FEA results. The internal highest temperature of the initial placements is 90.369°C. After optimization, the internal highest temperature is 86.128°C, the highest temperature be reduced more than 5°C. It can effectively deal with the problem about optimize the thermal placement of EPCM chips, and improves the internal thermal distribution.