Advanced Materials Research Vols. 328-330

Abstract: The pavement performance of asphalt mixture and its adaptability to features of application area, cost estimation and harmonic relationship between performance and cost were studied and analyzed in this paper, evaluation model of technical and economic performance of asphalt mixture was constructed, evaluating indicators of technical and economic performance of asphalt mixture as performance matching coefficient, cost conversion demarcation coefficient and harmonic factor of performance and cost and corresponding calculation methods were proposed. On this basis, discrimination function of performance and cost was built to provide theoretical basis and decision support for selecting a satisfactory asphalt mixture scheme which had the best pavement performance and economic performance under certain natural and constraint conditions, it can provide a reference for the development of assist decision function of managerial system of pavement maintenance as well.

Abstract: Combining with productive practice, production of intermediate castings in high-strength turbochargers under the condition of intermediate frequency furnaces is analysed in this paper. By adopting measures of compound inoculation and increasing Sulfur, 95% type A graphite and high-strength intermediate castings whose tensile strength is 300 MPa are acquired. Furthermore, moderate amounts of S and Mn as well as CE values are determined according to test results. As for thin-wall gray cast iron with high strength and complicate structure, when w _S is low and w _C is high, castings with good graphite form can be produced. But it is not stable and the strength is low. Adding inoculants like Calballoy and Si-Ca-Ba can significantly improve the graphite form on the edge of thin-walls. When w _C is stabilized at about 4.1, stable and continuous production of high strength gray cast iron with good graphite form can be guaranteed by adding sulfur and controlling the amount of Mn. The proportion of A type graphite and that of pearlite are both more than 90%.When high-strength gray cast iron is produced in intermediate frequency furnaces, w _S should be controlled between 0.1% and 0.12% and w _Mn should be controlled between 0.5% and 0.55%.

Abstract: Austempered ductile cast iron is newly developed engineering material with a favorable combination of comprehensive mechanical properties. Its properties, such as good comprehensive mechanical properties, high fatigue strength, and good fiction and wear characteristics are included. The application of ADI at home and abroad was presented as well. In order to ensure and improve mechanical properties of ADI, it should ensure high rank nodularity in terms of nodular cast iron, improve graphite nodules, reduce segregation and properly cut down the content of silicon and manganese. While in terms of heat treatment, in order to achieve ideal austenite ferrites, stable and reliable heat treatment process as well as relevant equipment is required.

Abstract: The purpose of this paper is based on the cement-based materials by adding fibers and mineral admixtures for composite, to cement the improvement of liquidity. Experiment with the intensity level of 42.5 ordinary portland cement, by adding polypropylene fibers, slag and fly ash cement mortar as a mineral admixture, the production of cement mortar matrix for the test, were conducted on a variety of mix Fluidity test. Experiments show that the addition of polypropylene fiber is not conducive to the mobility of mortar, especially monofilament fiber was more obvious than the reticular fibers. To join the slag, fly ash, mortar fluidity increased, indicating that slag and fly ash added to improve the workability of cement-based materials. When the fiber content reaches the maximum degree of maximum flow, indicating that slag, fly ash and polypropylene fibers will increase the combined effect of fluidity value. This innovation is obtained by adding fiber cement-based materials for toughening effect, with the use of mineral admixture can improve the overall performance of cement based materials, with further research and promotion value.

Abstract: The formation of super-thin continuous dielectric film (e.g. the ion barrier film-IBF) on microchannel plate (a kind of porous substrate) is most important for prolonging the operating life of the third generation micro-light image tube. In this paper, firstly, the formation of Al₂O₃ ion barrier film on microchannel plate (MCP) using a new contamination-free technology was introduced. According to the analysis and the comparison with the traditional direct formation technology, it was found that the productivity of the new technology is better (90%) and the carbon contamination can be minimized. Next, the stopping and transmittance characteristic of the film for electrons were studied and the measurement principle was shown. In this measurement, the concepts of “dead-voltage” and “electron transmittance” were proposed to evaluate the stopping and transmittance of the film for electrons. The dead-voltage was 220V for the MCP covered the ion barrier film with a thickness of 5nm and the electron transmittance was over 90%.

Abstract: A six-point bending test was presented to simulate skin/stiffener debonding under anti-symmetrical loading conditions. A novel rig was design via which the anti-symmetrical bending deformations can be forced on to the specimens. Experimental study on six-point bending test of composite stiffened panels of T700/QY8911 was done by using this rig. The tests are numerically analyzed using the finite element code ABAQUS, modeling the entire stiffened panel by shell elements, and investigating the progressive delamination by means of the cohesive zone model. The results of numerical analyses are compared to the experimental ones in terms of load-displacement curves and debonding positions between skin and stringer. The experimental and numerical resulits show that the anti-symmetrical bending deformation is the main factor which results in the asymmetrical propagation of the debonding between the skin and the stiffener. The failure mechanisms of the test are similar to the ones which induces skin/stiffener debonding during post-buckling in the anti-symmetrical buckling mode.

Abstract: The negative effect of the conventional laser bonding caused by high temperature has been analyzed in the Si-glass bonding process. A new method which is the combination of chip surface activated pre-bonding and laser bonding has been proposed. The method has been used for Micro Electro Mechanical System package experiment. The process is: firstly, a hydrophilic surface was formed by using a special chemical method. Secondly, Si and glass were pre-bonded at room temperature. Finally, the laser with the wavelength of 1.070 μm, spot diameter of 480 μm, power of 70 W was local heated by the laser. This method achieves low-temperature bonding without external press. And the tensile test also shows that the strength of sample bonding reaches 2.8 MPa~3.2 MPa. So it not only ensures the quality of MEMS chip, but also reduces the cost of the package.

Abstract: Adhesive bonded T-joint is commonly applied in the manufacture of automotive structures. The objective of this work is the analysis of the load capacity of the adhesive-bonded T-joints under tension load and the influence causing by some parameters of adherend on the damage of T-joint. Thus, a series of tests were carried out and the balanced joint and the imbalanced joint concepts were proposed to illustrate the influence. And the results show that the imbalanced joints suffered greater stress concentration than the balanced one. Furthermore, by increasing the stiffness of adherends , one can increase the load capacity of a balanced joint. Meanwhile, in order to simulate the damage and failure processes in this type of joint, the cohesive zone model (CZM) based analysis was carried out using finite element method in ABAQUS. One can observed that only the upper end of adhesive layer transmits the load in the beginning.

Abstract: In recent years, internet based telerobotics has become more and more important in our lives and scientific research, there are many scholars dedicated to this research fields, especially the cooperation in the system. So, in order to research the cooperation problems in operator with operator, robot with robot and operator with robot in multi-operator multi-robot teleoperation system, built a two-operator two-robot telecooperation system, realized the two operators control the two robots cooperating with each other to complete items handover respectively. This article has given the solution of the items handover in the cooperative teleoperation system, designed the telecooperation robot system, given the specific experiment process and verified the feasibility of the scheme through the remote cooperation handover experiment. The realization of the system has the very prominent realistic significance, especially provides the experiment platform for the research of the multi-robot telecooperation system.

Abstract: In order to improve the performance of sponge iron for removing dissolved oxygen, sponge iron was originally modified by chemical replacement copper plating and the optimum modifying condition was obtained by orthogonal experiments. The effect of each modifying condition on the dissolved oxygen (DO) level in the outlet treated by modified sponge iron was investigated. The operating condition of packed bed was also investigated. The results showed that the performance of modified sponge iron for removing DO was improved obviously. The optimum modifying conditions were as followed: the concentration of CuSO₄·5H₂O was 40 g/L, citric acid was 80 g/L, the concentration of sodium tartrate was 45 g/L, the concentration of H₂SO₄ was 60 ml/L, modifying time was 120 s and temperature was 50 °C. DO in outlet water from optimum modified sponge iron packed bed increased initially and then decreased with increasing each modifying condition respectively. DO in outlet increased by increasing the flow rate or decreasing the bed height, and there were no DO detected when the packed height was 35 cm and the flow rate was not above 32 L/h.