Advanced Materials Research Vol. 661

Abstract: Ni-Ag core-shell nano particles have been facilely prepared by redox-transmetalation reaction of silver ions on the surface of nickle nano particles. As characterized by transmission electron microscopy (TEM), the as-synthesized core-shell particles were mono-dispersed and exhibited a narrow size distribution ranging from 200nm to 300nm. XRD analyses indicated both Ni core and Ag shell had an fcc structure. Furthermore, the thickness of silver shell was controllable via changing the mole ratio of Ag to Ni, which could show benefits for potential applications in optical, catalytic and electronic fields.

Abstract: Gold nanoparticles (AuNPs) were attached to the surface of alumina particles by an in-situ immobilizing method. SEM and XPS analysis showed that the coverage of alumina particles by AuNPs increased as the amount of alumina decreased; AuNPs onto alumina particles by the conventional colloidal deposition method were also prepared, whose TEM showed that the coverage of AuNPs was evidently smaller than that in the case of modified colloidal deposition method，although the AuNPs were spread almost uniformly over the surface of alumina particles. Au-immobilized alumina particles were subsequently utilized as the catalysts for direct amination of benzene with NH3H2O as an aminating agent and H2O2 as an oxidant under mild conditions. The reaction conditions were optimized: when catalyst amount was 2.0 g, reaction temperature was 50 °C, NH3H2O amount was 60 mL, H2O2 amount was 30 mL, and reaction time is 2 h, Au-immobilized alumina particles showed the highest aniline yield (1.96 mg) for 25 mL benzene.

Abstract: NiO nanoarrays with different hierarchical porous structures were synthesized by using hard-template SBA-15. The analytic results showed that the mesoporous structure parameters of the as-prepared NiO nanoarrays increased obviously with the increase of the addition of SBA-15 to a certain extent. The results may be helpful for the utilization of NiO as supercapacitors.

Abstract: Calculations have been performed for the relaxed structures and electronic properties of Ni nanobelts with the cross-section 3×3, 3×5, 3×7 and 3×9 atomic layers, using the first-principles projector-augmented wave (PAW) potential within density functional theory (DFT) framework. For all of the four size Ni nanobelts, the most atoms relax inward and the magnetic moment decrease as the belt width increase. Compared with bulk Ni, the freestanding Ni nanobelt offer strong spin polarization at the Fermi level as well as considerable magnetic moment. Thus such structures can be potentially utilized to design magnetic nano-devices.

Abstract: Carbon nanotubes (CNTs), one of the important symbol to enter the era of nanotechnology, becomes the most attractive materials with the unique properties, and CNTs shows extensive potential application in drug molecular transmission, CNTs tip and CNTs-based sensors. However, the application of nano-device requires more accurate research about geometric, electronic and mechanical properties which matches to radial breathing vibrational mode in Raman spectroscopy experiment. The shapes and frequencies of radial breathing mode(RBM) and radial breathing-like mode(RBM-like) were investigated by the modified beam element model based on molecular mechanics, and the relationship of frequencies of zigzag and armchair CNTs with length - diameter aspect ratio, diameter and chirality were also discussed respectively. The results show that there are RBM and RBM-like in radial vibration of CNTs, and their frequencies are approximate.

Abstract: Optical components at the nanoscale are crucial for developing photonics and integrated optics. Device with ultrasmall dimensions is of particular importance for nanoscience and electronic technology. Among all the manufacturing tools, the focused ion beam is a critical candidate for machining and processing optical devices at the nanoscale. Here, we experimentally demonstrate the fabrication of nanodevices with arbitrary shapes and different potential applications using focused ion beam techniques.

Abstract: Subwavelength nanohole arrays have been thoroughly studied for years. However, investigations on nanoholes with defects are seldom reported. Here, we study the optical properties of nanohole arrays with different defects which are fabricated by focused ion beam lithography. Finite difference time domain simulations are also performed to verify the experimental results. Our approach may find extensive applications in sensing and optical waveguiding.

Abstract: The GdF₃:Eu³⁺ and NaGdF₄:Eu³⁺ powders were synthesized by hydrothermal method as raw material of Gd₂O₃, Eu₂O₃, NaF, NH₄HF₂, EDTA and polyethylene glycol. The powders were characterized by means of X-ray powder diffraction, SEM microscopy and Molecular fluorescence photometer. It was discussed that the pH value of aqueous solution had affection on the phase composition of synthesized powders. The complex fluorides GdF₃ and NaGdF₄ were synthesized in aqueous solution at the pH values between 3 and 6. The synthesized powders were single hexagonal phase of NaGdF4 crystal at pH=8. It was also found that different fluorescence properties were exhibited by Eu³⁺ doping powders synthesized at different pH values of aqueous solution. The synthesized powders of GdF₃ and NaGdF₄ were excellent fluorescence materials.

Abstract: In the molding process of the tri-component composite spinning, the flow control of each component plays a significant impact on extrusion swell. This paper simulates the extrusion swell of the tri-component fiber in different flow ratio of different components based on Polyflow fluid dynamics simulation software, and measures the extrusion swell ratio of the tri-component fiber in different flow ratio of different components through the experiment. Simulation and experimental results show that by adjusting the melt flow ratio of the various components, we can obtain the desired extrusion swell ratio, which can improve the performance of the tri-component fiber.

Abstract: In this work, long-circulating doxorubicin hydrochloride (Doc) liposomes were prepared by the of ammonium sulphate gradients with ethanol injection, and the methoxy polyethylene glycol (mPEG) was added to modify the membrane property of the liposomes. The long-circulating mPEG-modified Doc liposomes were nearly round with a particle size ranging from 50 to 70 nm. The entrapment efficiency of Doc was determined to be 57.53 %. Meanwhile, the experiment results indicated that the long-circulating Doc liposomes show good sustained release property.