Advanced Materials Research Vol. 800

Abstract: The characteristics of welding process for aluminum-copper dissimilar material such as friction welding, explosive welding, brazing and cold pressure welding are discussed firstly in this paper. Then the welding technology and its application for aluminum-copper dissimilar material are summarized. Finally, the outlook is analyzed for the welding process of aluminum-copper dissimilar material.

Abstract: Cubic Cu₂O nanoparticles were synthesized via hydrothermal route without template. The study of different reaction conditions reveals that the concentrate of NaOH affects the size and the morphology of nanocubes.

Abstract: An efficient approach for fabricating three-dimensional (3D) photonic crystals (PCs) embedded defects via lithography was introduced. The resulting structures of plan view and cross-section of 3D PCs are characterized by field emission scanning electron microscopy. Ultraviolet-visible transmission spectra show their optical properties. The 3D PCs embedded defects change the center wavelength of photonic band gaps (PBGs) in original PCs, which can be applied in modification and control of the diffraction properties for optical devices.

Abstract: The soft magnetic properties of Fe-6.5wt.%Si alloy powders produced via high pressure gas atomization under different powder sizes, environments (atmospheric and vacuum) and heat-treatment were presented by vibrating sample magnetometer (VSM), respectively. It is found that the soft magnetic properties of powder gradually grow up as the increasing of the powder size under atmospheric and vacuum environments. However, the using of vacuum environment has an optimal capacity to strengthening the properties rather than atmospheric environment. The heat-treatment of 1000°C for 2 hours offers considerable potential for improving the soft magnetic properties of the powders.

Abstract: t is a familiar truth for engineers in the 21^st century that FRP (Fiber reinforced polymer) is getting widely used in civil engineering. FRP is light-weight and high strength, so most of the tensile structure and bending structure can be substituted with FRP. Though the application is becoming wider and wider for FRP products, the durability is still in concern for the engineering properties in the future. This article proposed a review of the GFRP (glass fiber reinforced polymer) concrete, and a brief introduction of the application in the right now China construction Projects.

Abstract: Water-soluble fluorescent carbon nanodots (C-dots) with strong photoluminescence were synthesized on a large scale by a facile, one-step and mild pyrolytic route using ammonium citrate as carbon source. The as-prepared C-dots exhibited low cytotoxicity, excellent biocompatibility and preeminent multicolor photoluminescent properties. Furthermore, the cellular internalization of the obtained C-dots was evaluated and the results reconfirmed the C-dots potentials for bioimaging.

Abstract: At present the wear and friction of pantograph-contact line is studied widely, while the research of the run-in process is little. In the paper they are obtained that the contact area is 0.96mm², contact stress is 73MPa, current density is 520A/mm², the contact resistance is 0.01583 and the contact temperature is 2797K on the surface of slide during the run-in period by the theory calculation. The high temperature of slide surface leads to the oxidation damage. While the carbon film comes into being and the friction surface is tending towards stability.

Abstract: The effect of technical factors on the quality of surface composite layer is studied by conventional cast-penetrating process. The result indicates that the high-quality surface composite layer is prone to get when pouring temperature is suitable and the suitable pouring temperature is 1650°C for little cast steel. Appropriate thickness of coating layer is benefit to get surface composite layer with high quality and the quality of sample with 5mm coating layer is better than other samples in test. Surface composite layer with high quality is easy to obtain when coating layer is located in the side of foundry mould.

Abstract: Atomic force acoustic microscopy (AFAM) is a technique combining the atomic force microscope (AFM) and ultrasonic technique, where the cantilever or the sample surface is vibrated at ultrasonic frequencies while a sample surface is scanned with the sensor tip contacting the sample. At a consequence, the amplitude of the cantilever vibration as well as the shift of the cantilever resonance frequencies contain information about local tip-sample contact stiffness and can be used as imaging quantities. It has been demonstrated to be a powerful tool for the investigation of the local elastic prosperities of sample surface. The sample is tested in the contact mode, the resonant frequency of the cantilever is measured, by which the contact stiffness is calculated based on the model of vibration of the cantilever, and then the elastic property of sample is evaluated according to the contact theory. Therefore, the contact model has an important impact on the calculation of elastic modulus. This paper analyzes the contact model between the AFM probe and the sample, and it is investigated based on finite element method (FEM) that the results of the test are affected by parameters.

Abstract: The aim of this study is to understand the effect of hydraulic classification on the iron ore tailings, and develop the cementitious activity of tailings to prepare construction materials. It was indicated that hydraulic classification can effectively divide the particulates of tailings into coarse and fine powders. The compression strength of the prepared construction materials are 87.83 MPa at 28 days, which have higher strength than the construction materials using original tailing, The variation in the tailings samples after hydraulic classification and the cementitious material after step-milling was characterized by sieve analysis, complete chemical analysis, scanning electron microscopy (SEM), and the particles size distribution. By mechanical properties testing and microstructure analysis shows that after hydraulic classification of tailings under the same conditions, the strength of the 3 days, 7 days, 28 days are higher than that of the original tailings. The main phases in the system are the rod of ettringite and low crystallinity or the amorphous C-S-H gel, and residual Ca(OH)₂.