Advanced Materials Research Vol. 738

Abstract: Plastic materials have many uses. The plastic optical fiber with a low-cost, light weight, good flexibility, big core diameter, easy coupling, anti-electromagnetic interference and electromagnetic radiation, is used for short range communication. This paper analyzed the characteristics of plastic materials and plastic optical fiber, and proposed a novel application technology for access network. In the access network, the plastic optical fiber is used as a transmission medium, from center router to the server, and the various floors of plastic optical fiber switch to the user using plastic optical fiber connections, constitute a plastic optical fiber local area network, to realize the true meaning fiber to the home.

Abstract: The transport properties of microencapsulated phase change material (MPCM) suspension are helpful for selection of components in the MPCM suspension transport system. The properties of MPCM sample are investigated theoretically. Transport property of MPCM suspension, especially pressure drop in pipe system, has been identified by theoretical analysis. The experimental researches in transport capability and power consumption of MPCM suspension are investigated as well.

Abstract: In this article, calcium sulfate spherical particles were prepared to be used in alveolar bone defect repairing. We used α-calcium sulfate hemihydrate powder to prepare spherical particles of calcium sulfate with stir pelletizing method. The effect of powder addition, pelletizing time and concentration of water-glass on properties of the spherical particles were studied. It was indicated that with increasing of the powder addition, the particle size of the spherical particles was decreased. Prolonging the pelletizing time can improve the compression strength in certain conditions. With increasing of the concentration of water-glass used in preparation process, the shape of the spherical particles becomes non-circular, the granulous stem yield was decreased and the compression strength of the spherical particles was improved.

Abstract: Ab initio electronic structures for β-Ge₃N₄ are investigated using ultrasoft pseudo-potential method within the generalized gradient approximation functional. The lattice parameters are predicted theoretically, and are compared with available experimental data and the other theoretical results. The elastic constants calculations reveal that the phenacite structure is a stable phase in the pressure range of 020GPa. The high bulk modulus (B=180.2GPa) indicates that β-Ge₃N₄ is a relatively hard material. β-Ge₃N₄ has a direct band gap of 2.94eV, indicating its promising applications as a semiconductor in electronics and optical fibers. On the other hand, the density of states analysis is also included in this paper.* Corresponding author: CHEN Dong

Abstract: The structural and elastic properties of the cubic spinel Ge₃N₄ semiconductor have been investigated using the ab initio scheme within the generalized gradient approximation in the framework of density functional theory. Quantities such as lattice constants and elastic constants of interest are calculated. A good agreement is found between our results and the other data. Through the lattice dynamics, in which the finite displacement method is used, we have obtained successfully the thermal properties such as the phonon curve, free energy, heat capacity and Debye temperature in the whole temperature range from 0 to 1000K. It is the authors ambition that these results will inspire further experimental study on the Ge-based semiconductors. * Corresponding author: CHEN Dong

Abstract: Hydroxyapatite is well used as bone repair materials, due to its properties that can be combined with strontium to improve mechanical property and degradation property. In this article, hydroxyapatite whiskers with different amount of doped strontium were prepared with diammonium phosphate, calcium nitrate and strontium nitrate at 94 °C. Fourier transform infrared spectroscopy (FTIR) was used to identify the functional groups. X-ray diffraction (XRD) analysis was carried out to study the phase composition and crystallinity of the whisker. The morphology of the whiskers was characterized by scanning electron microscope (SEM). It was indicated that strontium can be doped in hydroxyapatite with proper process and then the strontium-doped hydroxyapatite whiskers were produced successfully.

Abstract: A new Bi5Sb8SnRE quaternary alloy was formed by adding 0.25wt%-0.75wt% rare earth (RE)Er into Bi5Sb8Sn solder alloy to study the effect of its mechanical property.The results show that adding micro amount of Er could refine the microstructure.Meanwhile,more uniform microstructure,improvements of the mechanical properties were obtained with Er additon.Comparing with Bi5Sb8Sn matrix, the tensile strength and shear strength increased by 41.8% and 83.0% respectively when Er adds up to 0.5wt.%; However,the Microstructure coarsened and the mechanical properties were decreased when the addition of Er more than 0.5wt.%.

Abstract: Growing requirements of small-batch, high-quality and customized products are motivating the development of innovative flexible polymer processing techniques. The paper demonstrates the possibility of employing the multi-point forming (MPF) technology to produce low-cost, small-batch and customized polycarbonate (PC sheet components. Experiments have been performed by means of an experimental setup designed for processing polymer sheet and the overall investigation is focused on the characterization and evaluation of the effects of processing parameters on forming quality. The results show that the forming defects can be eliminated under appropriate processing parameters and that the shape of formed part is in good accordance with the desired shape.

Abstract: Porous calcium sulfate/hydroxyapatite whiskers composites scaffold is possible to be used in bone tissue engineering, for its biocompatibility, controllable degradation, and good mechanical properties. In this study, porous calcium sulfate/hydroxyapatite whisker composite scaffolds were fabricated by adding pore-forming agent and were characterized. The characteristics of the porous scaffolds were assessed by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and immersing testing techniques. It is shown that the scaffolds prepared in this article have the porous structure with the content of CaSO₄ and HA. The scaffolds prepared in this article have been confirmed to be ideally used as biodegradable implants.