Advanced Materials Research Vol. 549

Abstract: Research progress of preparation methods of nanofibers was briefly reviewed and discussed based on the classification of two component composite method, template synthesis method, polymer limited domain synthesis method, and electrospinning method. Research orientations related to preparation methods of nanofibers were also proposed.

Abstract: Have studied microstructure of the gas nitriding layer and the laser quenching/ nitriding layer using the X-ray diffractometer and the transmission electron microscope to the brittl of nitriding layer. The results show that the content of Fe3N in composite nitrided layer increased from 14.74% to the 69.45%, while the crisp hard ξ-Fe2N content dropped from 79.95%to 25.03%, Especially the Cr2N particles are much finer and the depth of the nitrided layer increases. There have phase relation, coherence and compatibility between γ'-Fe4N and α-Fe. spherical particles of cementite was formed in lower strip bainite, while the γ′ of gas nitriding diffusion layer is big, the carbide assumes the long strip off and with distributing certain directivity. Brittleness of laser hardening/ nitriding layer reduces.

Abstract: A convenient method had been developed for preparing antistatic Poly(ethylene terephthalate)/multiwalled carbon nanotubes (PET/MWCNTs) nanocomposites. Polyaniline (PANI) was employed to coat MWCNTs as interfacial modifier. At first, the PANI-coating MWCNTs (PANI-c-MWCNTs) were prepared via miniemulsion polymerization of aniline at the presence of MWCNTs. The TEM images, FT-IR spectra, UV-Vis spectra and electrical conductivity were investigated, which indicated that the MWCNTs were coated with a conductive PANI ultrathin film while the morphology and electrical property had almost no damage. Then the PANI-c-MWCNTs were added into PET through in-situ polymerization method. The TEM images indicate that PANI-c-MWCNTs could be well dispersed in PET matrix, which had important positive effects on the electrical conductive properties of PET/PANI-c-MWCNTs nanocomposites. The results indicate that the electrical conductivity of PET/1.0 wt% PANI-c-MWCNTs nanocomposites reaches the antistatic level.

Abstract: In this paper, Button rock asphalt particle was directly added into hot asphalt mixture (HMA) to produced high modulus asphalt mixture (HMAM). In order to evaluate the performance properties of HMAM with BRA, dynamic compressive complex modulus (E*) test, rutting test and moisture resistance test were used to investigate HMAM with BRA and HMA with SBS modifier. Test results indicate BRA can greatly improve dynamic E*and rutting resistance of HMA compared with SBS modified asphalt mixture. Moisture resistance ability of HMAM with BRA has the same level with SBS modified asphalt mixture. Therefore, BRA particle can be used to produce HMAM, which have more superior performance properties than SBS asphalt modifier.

Abstract: The cordierite porous ceramics were made from kaolinite, talc and α-alumina, formed by pressing and fired at 1200 °C for one hour. Starch was used as pore-forming agent. Physical/chemical properties and microstructure of products were characterized. The results show that samples exhibit relatively high strength, low coefficient of thermal expansion and well-distributed gradient pores. The pores of samples are homogeneous.

Abstract: 4Cr5MoSiV1 steel, a widely used for hot work mould, contains Cr, Mo, V alloying elements that easily form carbides. The Micro-area chemical composition, microstructure, impact toughness and thermal fatigue behavior of 4Cr5MoSiV1 and 4Cr5MoSiV1H steels were investigated, the latter was carried on high temperature homogenizing and solution based on the former. The results showed that bulk eutectic carbides and elements segregation contained in the 4Cr5MoSiV1 steel reduced the impact toughness. But the impact toughness of the core of the mould steel block and thermal fatigue property of 4Cr5MoSiV1H steel were improved because the elements segregation and eutectic carbides was eliminated through the high temperature homogenizing and solution.

Abstract: Energy demand to ensure a comfortable environment for humans has increased worldwide, especially in the application of phase change material (PCM) for resident living. In this paper, the current applications of PCMs including solar water-heating system, solar cooker and residential building aspects were presented, and the suggestions for future works were also discussed.

Abstract: Double field detection method can effectively solve missing detection and mistake detection problems. But because the image data is two times as single field detection, and therefore the detection speed is slow. A new Processing flow is put forward. Firstly, the suspected defect images are filtered out, and only the images that contain defects can be processed in the follow programs. Secondly, the retained suspected defect images are divided into two categories. Different categories are handled by different process. The simulation experiment result shows that: it not only makes full use of the advantages of the double field method, and greatly reduces the image data quantity, at the same time ensuring the real-time of the system.

Abstract: The response of functionally graded material flat spherical shells subjected to thermal loading is studied using the method of lines. Based on the Kirchhoff straight normal hypothesis and Von Karman's geometrically nonlinear theory, the governing equations are obtained. A semi-analytical numerical method, viz. the method of lines is introduced. Then, the partial differential equations are transformed into ordinary differential ones. The numerical results of flat spherical shells are given and compared with ones of the finite element method. The effects of the material gradient parameters on the responses are discussed in details.

Abstract: Nano-TiO₂ photocatalyst powders were prepared through the sol-gel method and supercritical fluid drying(SCFD). The TG-DTA、XRD、particle size distribution technique、SEM were used to characterize the hyperfine TiO₂ particles.The lanthanum-doped TiO₂ with different mass percentage of La³⁺ were compared with pure TiO₂ when used as photocatalyst in degradation of methyl orange. The best catalytic activity was observed with 0.02(mol)%La-TiO₂. Photocatalytic efficiency of the 0.02(mol)%La- TiO₂ is improved by 30.79% comparing to pure TiO₂.