Advanced Materials Research Vols. 941-944

Abstract: In the present paper, the Co-doped Fe₃O₄ nanoparticles have been successfully synthesized by the co-precipitation process. The morphologies size of the Co-doped Fe₃O₄ nanoparticles were characterized using scanning electron microscopy (SEM). The structure of the products were characterized by Xray diffraction (XRD). The composition of the product was analyzed by energy dispersive X-ray detector (EDS). The results show that the phase structure of the Co-doped Fe₃O₄ nanoparticles is spinel Fe₃O₄ with the particle size ranging from 40 to 50 nm. The prepared Co-doped Fe₃O₄ nanoparticles electrode was then applied to detect hydrogen peroxide (H₂O₂) in 0.01 M pH 7.0 phosphate buffer medium.

Abstract: Electrospinning has been applied to prepare uniaxially aligned nanofibers made of organic polymers, ceramics, and polymer/ceramic composites. The highly aligned PAN nanofiber was successfully fabricated by the simple rapid method for preparing parallel micropipette electrodes. The effect of collect distance on the degree of aligned nanofibers and diameter distribution as well as the variation trend was explored and reseached.

Abstract: In order to profile the research status of carbon nanotubes (CNTs), and gasp the development direction of the subject, based on the database of INSPEC, with the help of INSPEC thesaurus, using co-word clustering, 8 important subfields of CNTs are identified in this paper. Furthermore, the trends of each subfield with time was showed as well as the journal distribution of each subfield was analyzed. The result should be focused on to provide the institutions, researchers and decision makers of CNTs with useful reference.

Abstract: Ag doped ZnO microrods are prepared on c-plane sapphire substrates by chemical vapour deposition method at high temperature.The morphology, structure and optical properties were investigated by scanning electron microscopy, X-ray diffraction and Raman spectrum, respectively. The prepared Ag doped ZnO microrods have good preferred orientation with very limited structural defects. The Raman bands indicates that a tensile stress existed in the sample and an additional local vibrational mode related to Ag is also found which can be used to confirm the existence of Ag in the Ag doped ZnO microrods.

Abstract: Highly water-dissolvable Na2SO4 nanorods were prepared by introducing Ca2+ and NO3- as shape-control agents. The diameter of the as-synthesized nanorods was basically in the range of 20-40 nm, and the length was in the range of 500-800 nm. It was also found that Ca2+ can restrict the growth of the nanocrystals on a given face and the NO3- can also selectively adsorb on a given face and favor the growth of the nanocrystals and the Cl- may help to form uniform nanorods. The synthesis procedure was also simple, and the as-synthesized nanorods may provide ideal templates for preparing nanotubular materials.

Abstract: Electrospinning represents a simple and convenient method for generating polymer fibers has been widely applied to produce porous nanofibers. The PLA fibers obtained in this research showed a significant nanoporous surface by varying solvent compositions of chloroform (CF) and N,N-dimethylformamide (DMF).The nanopores produced by phase separation of solvent system were observed by means of scanning electron microscope.The approach showed the fabrication of electrospun nanoporous fibers possessing ultrahigh specific surface area without any post-treatment.

Abstract: Polyethylene glycol (PEG) hydrogel microstructures with various shapes and sizes on a glass chip were prepared by a simple and rapid ultraviolet (UV) irradiation method using a metal mask. Photocurable PEG solution prepared by mixing 95 wt.% polyethylene glycol diacrylate and 5 wt.% 2-hydroxy-2-methylpropiophenone as a photo-initiator was injected to the gap between bottom and upper glasses in a simply assembled glass chip. After a metal mask with line-and-space or complex patterns was placed on the glass chip, UV light from a spot UV irradiation device was exposed to the glass chip through the metal mask for 7 seconds at UV intensity of 26 mW/cm². Then the PEG hydrogel micropatterns on the glass chip were obtained after removing unreacted PEG solution by air blowing. To prepare more rigid microstructure, the prepared PEG micropatterned chip was exposed under UV light for 20 seconds. Then the PEG hydrogel micropattern chip was fabricated by a simple and rapid procedure. Micropattern transferring was performed from the PEG hydrogel chip to polydimethyl siloxane (PDMS) replica by a solution casting. The prepared micropatterned PDMS replicas showed similar shape and size of microstructures compared to that of the corresponded PEG hydrogel chip. Thus the PEG hydrogel microstructures on a glass chip could be used as a mold to fabricate micropattern PDMS chips for nanobio-chip applications. Furthermore, the present method provides large scale chip fabrication, more than 4 cm-length and 4 cm-width in a single step, not only PEG hydrogel chips but also PDMS chips.

Abstract: The objective of this study was to research the performance of the electrospun polystyrene-acrylic resin composite nanofibre on the adsorption of gaseous aromatic compounds, such as benzene and chlorobenzene. The equilibrium adsorption amount of benzene was 254.3 μg mg^-1, while the equilibrium adsorption amount of chlorobenzene was 2.5 μg mg^-1. The dynamic adsorption of the two compounds onto the composite nanofibres was also studied. Comparing with the conventional adsorbent (Tenax-TA), the performace of this nanofibre was well as that of Tenax-TA. The results of comparison confirm that electrospun nanofibres can be a potential adsorbent for the sampling of gaseous aromatic compounds.

Abstract: Surface Self-nanocrystallization (SSNC) can produce nanometer grains (10~50μm depth) in the surface layer of metallic materials. And high strength, residual compressive stress as well as a mass of defects attributed to grain refinement and severe plastic deformation, greatly improve their surface properties, such as strength, wear resistance, diffusion property, fatigue performance and corrosion resistance. Now some methods have been confirmed which could realize surface nanocrystallization. This paper reviews the study of surface nanocrystallization and simply summarizes changes in their performance based on surface layer microstructure of metallic materials.

Abstract: In the process of carbon nanotube assembly by dielectrophoresis, the geometry and spacing of electrodes are significantly affecting the assembly precision. In the simulation process, we showed the geometrical shape of conical, round and rectangular electrode and compared the electric field distribution with these electrodes. Compared with single electrode pairs, comb electrodes can achieve high-yield manipulation. Simulation results show that when the distance between adjacent electrode pairs is larger than twice electrode width, it will avoid electric field superimposition. A method of using floating metal posts within the electrode gap can realize precise positioning of assembled carbon nanotubes.