Advanced Materials Research Vols. 79-82

Abstract: In order to prepare a time decay-resistant electromagnetic shielding (ES) fabric with good handle, moisture permeability and antibacterial properties, Cu, Ag, Ag/Cu and Ag/Cu/Ag films were deposited on PET non-woven by sputtering in screening experiment. Considering the post continues processing, this study focuses on discharge parameters optimum for a limited short time. Relationship was studied between deposited rate and ES effectiveness (ESE) for the four metallic films on various substrates. The metal deposit greatly relays on the chemical nature of the substrate and target metal category. The deposited metal rate on metal is larger than that on PET. In comparison with single metallic film, the dB value of multi-metallic film obtained for same time even for more time remarkably dropped. Therefore, an Ag-coated PET no-woven was finally fabricated as the multi-functional fabric with anti-decay ESE. The multi-functional PET no-woven with good handle obtained for 3min. by optimizing other parameters exhibits higher ESE, good anti-bacterial and moisture permeability.

Abstract: In this study, polyaniline (PANI) was prepared by electrochemical method on the surface of active carbon (AC) electrodes. The physical and electrochemistry properties of AC/PANI composite compared with pure AC electrode were investigated by scanning electronic microscope (SEM), galvanostatic charge/discharge test and electrochemical impedance spectroscopy (EIS). The AC/PANI composite electrodes showed much higher specific capacitance (624 F•g-1), better power characteristics and were more promising for application in capacitor than pure AC electrodes.

Abstract: In this study, we aimed at producing a MFNP consist of a dielectric core encapsulated fluorescein coating by a thin gold shell, which facilitate it with highly favorable optical and chemical properties for biomedical imaging and therapeutic applications. We have composed a novel multi-functional nanodesign, Sample A3, with fluorescein encapsulated in SiO2 nanoparticles with gold shell. The A3 nanoparticles were uniform in size, no aggregation, homogeneous and stable in the solution under the SEM image system. We have also investigated its cytotoxicity to A10 human smooth muscle cell line by MTT assay, and found that the novel sample A3 were of little cytotoxic to the cells. In conclusion, we have proposed a novel method of preparing multi-functional nanoparticles assemblies, which has added fluorescein to SiO2 in a gold shell, to make it simultaneously have the functions of photothermal therapy and tracer.

Abstract: Nanocrystalline α-Al2O3 powders were synthesized by low temperature combustion technique using aluminum nitrate-urea reactive system. The relationship between the color of powders and the mass ratio of aluminum nitrate-to-urea was investigated. X-ray results showed presence of the well-crystallized α-Al2O3 after calcined at 1100oC for 2h with 2.5:1 mass ratio. The grain size of α-Al2O3 powders was calculated by Scherrer equation. TEM observation and Clouter N4 Plus measurement results showed that the particle size distributed from 20 nm to 70 nm.

Abstract: The Cr-Cu-N nanocomposite thin films with copper contents ranging from 1.6 to 24.1 at.% were deposited on silicon wafer substrates using a bipolar asymmetry pulsed DC reactive magnetron sputtering system. A dense and compact structure was observed for the thin film containing higher than 10.2 at.% Cu, whereas columnar structures were revealed on the coatings with less than 10.2 at.% Cu. Heat treatments of the as-deposited thin films were held in a vacuum tube furnace at 400, 450 and 500oC for 30 minutes, respectively. It was observed that the copper atoms would diffuse to the surface to form oxide particles on the coating contained higher Cu content after heating higher than 450oC. The quantity and size of the oxide particles increased with increasing heating temperature and Cu content in the thin film. The hardness of coatings increased after heating except #D thin film containing 24.1 at.% Cu, which the softening effect was found after heating at 500oC. A granular and less dense cross-sectional morphology was observed on #D coating after heat treating at 500oC, which was responsible for the lower hardness of thin film.

Abstract: Composite materials, having advantages of high specific strength, high specific stiffness, are used in many applications, such as musical instrument, acoustical tile, fire wall, sports equipment, aerospace and vehicle industries. Composite products in the form of sandwich structures are specifically useful in recent years. In this paper, the bending strength of sandwich structure made by graphite/epoxy face laminates and core material made by multi-walled carbon nanotubes (MWNTs) reinforced polymer was investigated experimentally. In experiment, the three-point bending test was performed to measure the bending properties of sandwich beams. The influences of fiber orientation in the face laminates and MWNTs content in polymer reinforced nanocomposite core material on the bending strength of sandwich beams were discussed in this paper. The failure mechanism of sandwich beams with various fiber orientations in the face laminates was also discussed.

Abstract: Titanium based nanotubes (8-12nm outer diameter and 4-6nm inner diameter) were successfully fabricated by a simple and cost-effective hydrothermal method. The nanotube-like amorphous phases TNT(Na) and TNT(H) were obtained with different post treatment. The samples were characterized by means of high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), selected area electron diffraction (SAED), energy dispersive X-ray spectrum (EDS) and UV-Vis diffuse reflectance spectroscopy (DRS). The photocatalytic activities of the nanotubes were evaluated using photo-oxidation of methyl orange.

Abstract: The catalytic cracking of methane to produce COx free hydrogen and a spectrum of advanced carbon nano materials was studied. Over several genres of catalysts by cracking of undiluted methane we produced hydrogen and highly graphitic carbon nanotubes (single-, thin- and multi-walled), straight microfibers, nano onions over the solid oxides solution, perovskite structured mixed oxides and mesoporous supported catalysts. The influences of reaction temperature on the methane conversion over various catalysts were investigated. The yields of carbon materials were monitored during the cracking running and the results indicated that these series of catalysts are promising for the commercialization of carbon nanotubes, microfibers and microballs.

Abstract: ZnS:Ag (Ag+-doped ZnS) nanoparticles have been synthesized through the hydrothermal route, and the effects of the molar ratio of S/Zn in reagents have been studied. The products are all cubic sphalerite structure, and the crystallinity is generally increased as this ratio rises. The ratio less than 1 leads to small particles less than 10 nm, and the ratio more than 1 leads to large particles between 20~30 nm. Luminescence properties of samples show significant dependence on the ratio. The sample synthesized using stoichiometric reagents during hydrothermal preparation exhibits the strongest blue emission in this series. There is significant defect luminescence in samples synthesized using nonstoichiometric reagents and the Ag-related luminescence is quenched in them.

Abstract: The ferroelectric ceramic BaTiO3 was synthesized at 1000 °C for 5 h. The structure of the system under study was refined on the basis of X-ray powder diffraction data using the Rietveld method. The system crystallizes in the space group P4mm（99）. The refinement of instrumental and structural parameters led to reliable values for the Rp, Rwp and Rexp.We use the TOPAS software of Bruker AXS to refine this ceramic powders and show its conformation