Advanced Materials Research Vols. 562-564

Abstract: Pipeline repair and reinforcement technology can generally be categorized into three main types: Welding, Clamp, Fiber Composite. Fiber Composite Repair recently undergoes fast development because it does not require heat or welding and can be directly applied to high pressure transmission pipeline. This article summarizes Fiber Composite Repair technology and its mechanism, also compares the application characteristics of Glass Fiber, Carbon Fiber and Basalt Fiber composites and finally concludes broad application prospects of Carbon Fiber Composite in pipeline repair and reinforcement.

Abstract: The aim of this work is to prepare a kind of polymer-based form-stable PCM with a higher thermal conductivity. Graphite powders modified by titanate coupling agent were chosen as the thermal conductivity enhancer. The modified graphite(MG) and capric acid(CA)-myristic acid(MA) eutectic as thermal absorbing material were blended into the poly-methyl methacrylate (PMMA) serving as supportive matrix during the bulk-polymerization process of MMA. The composite PCMs with different MG mass fraction (2%, 5%, 7%, 10% and 15%) were characterized by SEM, DSC technique, volume expansibility measurement and mechanical test. Thermal conductivities of the composites were measured by transient hot-wire method. The results indicate that the MG/CA-MA/PMMA composites keep the good thermal storage performance while the thermal expansibility becomes weaker. Thermal conductivity of the composite PCM has been enhanced significantly.

Abstract: A novel kind of supramolecular structrued hydrogels were fabricated by Diels-Alder click reaction between furan-functionalized polypseudorotaxanes and polymeric dienophiles. Firstly, polypseudorotaxanes were prepared by supramolecular self-assembly of furan-terminated poly(ethylene glycol)(PEG) and α-cyclodextrins (CDs) in water. And polymeric dienophiles were synthesized by a coupling reaction between copolymer of hydroxyethyl methacrylate and N,N-dimethyl acrylamide and N-maleoyl alanine (AMI). The supramolecular structured hydrogels were prepared by Diels-Alder reaction in water.

Abstract: A baseline method to determine directly the solid fraction using the cooling curve was proposed for solidification of undercooled melts. To construct the baselines, a sudden function ξα(x) is introduced. In terms of present method, the solid fractions during solidification of Zr metal and Al-7wt.%Si alloy were predicted. The predictions coincide with the results of the available methods.

Abstract: Removed at authors request

Abstract: The natural gas hydrate is a clean, efficient and abundant energy sources. Accordingly some countries give their attention to it and research by mint fund and manpower. However our country is late in this field. The researchers commenced their study in the end of 80’s, when they made vast pilot study such as investigation and data processing. With the support of our country, at the beginning of 90's natural gas hydrates was artificially synthesized for the first time, and at this century the mineral resources of natural gas hydrate was detected in the East China Sea and the South China Sea .At the same time the researchers made great research on the mechanism of formation, dynamic mechanism and formation conditions. However we are confronted with the problem of exploitation and the greenhouse urgently.

Abstract: In this paper, A novel domestic straw gasifier, with an inner U-shaped tube in which porous ceramics was placed to crack the tar carried by producer gas, is put forward. From experiments results, it can be investigated that producer gas with low tar content and high heat value could be obtained.

Abstract: Aluminum-containing silicon carbide (SiC/Al) fibers were fabricated by electrospinning a polyaluminocarbosilane (PACS) solution followed by the pyrolysis of the electrospun fibers at 1200 oC in a nitrogen atmosphere after air-curing at 200 oC. The optimum electrospinning conditions were a 0.9 g/mL PACS solution with 20%DMF/20%THF/60% toluene composition, a 20 kV spinning voltage, a 2 mL/h injection speed and a 10 cm receiving distance. The obtained SiC/Al fibers have a diameter in the range of 0.7~1.5 m.

Abstract: Three-dimensional silica fiber reinforced silicon nitride composites were prepared by polymer infiltration and pyrolysis method using perhydropolysilazane (PHPS) and polyhydridomethylsilazane (PHMS), respectively. The microstructures of the composites were characterized by transmission electron microscopy. Strong fiber/matrix interfacial adhesion was observed for the PHPS-derived composites prepared at 1073K, and the PHMS-derived composites prepared at 873K without fiber precoating. While for the PHMS-derived composites prepared at 873K with fiber precoating, the coating changed the fiber/matrix interfacial bonding conditions, leading to high mechanical properties.

Abstract: ZnO/SnO2 nanocomposite powder were prepared by coprecipitation method with SnCl4·5H2O, ZnNO3·6H2O, HCl, NaOH as raw materials. Influence of different mol ratio of ZnO/SnO2 on the photocatalytic activity of ZnO/SnO2 nanocomposite powder was researched by the degradation of methyl orange as a reaction model. The particle size and dispersion of ZnO/SnO2 powder was characterized by transmission electron microscope(TEM). The results show that the photocatalytic activity of ZnO/SnO2 nanocomposite powder was increased significantly when compounded by SnO2, the photoactivating activity of ZnO/SnO2 powder starts increasing and then decreasing when the ratio of ZnO/SnO2 decreases. When ZnO:SnO2 is the ratio of 4:1(mol ratio)，the photocatalytic activity of ZnO/SnO2 nanocomposite powder is the best and the degradation rate of methyl orange is 42.09% when visible light illuminate for 225 minutes, particle size is 20-30 nanometer and dispersion is good.