Advanced Materials Research Vols. 482-484

Abstract: Make continuous extrusion test on cast AZ31 magnesium alloy by TLJ250 continuous extruding machine, and observe and compare the magnesium alloy changes in mould of cavity before and after extrusion and in process. Result shows that: after AZ31 magnesium alloy is extruded continuously, big shear deformation occurs to the material, and the grains become fine, forming fine and even equiaxial grains. When metal flows in the cavity, the metal on top and bottom has bigger deformation, because the grain sizes at product surface and heart are different due the feature of continuous extrusion

Abstract: This paper presents a design of indoor terminal with Bluetooth module in smart home. It includes Flash, SDRAM, Bluetooth module, Ethernet interface and RS-232 interface. The CPU of this system is GM8120. These form the platform for embedded Linux development. This paper describes the hardware design and implementation of indoor terminal, and the software design with Bluetooth and video information technology

Abstract: Lock-in amplifying (LIA) is one of important techniques of picking up weak signals buried in the noise, and is the core component of Tunable Diode Laser Absorption Spectroscopy (TDLAS) technology. Then we design a small size, dual phase lock-in amplifier (LIA) integrated circuit. This paper is based on the phase-sensitive detector AD630, together with the phase-locked loop (PLL) circuit (74HC4046) and the active filter (MAX275) the value of Q and the center frequency of which could be adjusted. The output signals were collected by A/D converter and dedicated high-resolution data acquisition card. The range of frequency is 500Hz-100 kHz, the dynamic range of acquisition signal is greater than 100dB, the signal-to-noise ratio is up to 60dB, and the overall area of circuit is only 14cm × 14.8cm. Experiments show that the design meets the requirements of integration into the system.

Abstract: Effects of thermal cycling on the tensile strength of aluminum alloy welded joints are studied experimentally in this paper. The damage mechanisms are also analyzed based on the microstructure observations. Results reveal that certain thermal cycling can cause strength decrease especially at the heat affected zone of the aluminum alloy welded joint. The cyclic temperature and the external load are the key factors which influence the strength of the welded joint specimens, while the cyclic period has a minor effect in thermal cycling conditions. Microstructure analysis also shows that voids nucleation and evolution governs the damage process under thermal cycling condition.

Abstract: Ti-SBA-15 mesoporous materials with different Si/Ti molar ratios were synthesized via a hydrothermal process and characterized by using various techniques. The effect of Si/Ti molar ratios in the gels on the structure and catalytic efficiency in epoxidation of cyclohexene was discussed in details. The results showed that all the Ti-SBA-15 materials retained SBA-15 mesoporous structure and exhibited good catalytic activity. Furthermore,the sample prepared with Si/Ti =50 exhibited the best catalytic performance under the reaction conditions.

Abstract: According to characteristics of the marine environment corrosion, 980MPa steel were developed. After design rational chemical composition and production process, the full section hot-rolled corrosion-resistant sorbite rail steel were successfully developed. this kind of steel has fine grain size, high strength and perfect toughness. Dry-wet immersion test showed that lift of this rail is 70% longer than U75V.

Abstract: Creativity has been rightfully considered to be one of the main resources of the 21st century. Only the growth of creativity and mobilization of the human innovative potential can secure an access to the reserve that is essential for successful and humane development of economy and society. According to a study by the Institute for Prospective Technology Studies, 70% to 80% of competitiveness and growth of enterprises will be based on new knowledge and skills of employees. This assumption is based on changes in the business environment of the 21st century – the continuing globalization of markets, intensifying competition, improving speed of innovation and the boom of information and communication technologies.

Abstract: The lamellar crystal orientation and crystal instable growth in polymer ultrathin films were studied. The orientation of lamellar crystal transforms from edge-on to flat-on with decreasing film thickness due to the enhancement of restriction effect of polymer-substrate on the edge-on lamellar crystals. Lamellar crystals in ultrathin films have a instable growth and become a dendrite at the growth front because of the diffusion-controlled growth.

Abstract: The consequences of distinct modes of loading procedures on the mechanical behaviour of elasto/viscoplastic materials are analyzed in the present work. An associated formulation of the evolutive laws is adopted based on the existence of a non-negative convex closed function representing the dissipative mechanisms. Distinct modes of loading modalities are suitably taken into account by considering different loading application rates and the intrinsic properties of the material. An adequate integration scheme is adopted and the effectiveness of the procedure is shown by analyzing specific computational applications with different loading programs. Numerical examples and results are also illustrated in order to show the significance of different loading procedures and different loading rates on the nonlinear behaviour of inelastic materials.

Abstract: The purpose of this study is to investigate the effect of various contents and modulus ratios of alkali activators on strength development and drying shrinkage of alkali-activated slag pastes. Experimental results show that the alkali-modulus ratio is the key factor influencing pH value and drying shrinkage. The lower the alkali-modulus ratio is, the higher the pH value is, and the lower the drying shrinkage is. In addition, the increase of the amount of alkali-activators decreases the initial and final setting time. The compressive strength of alkali-activated slag pastes is higher than that of Portland cement paste at all ages.