Advanced Materials Research Vols. 887-888

Abstract: In order to study the fabrication of T-shape combined micronozzle used for preparation of microcapsules, a gravity based apparatus for glass micronozzle was designed. A novel method for glass micro hole was proposed. The impact law of pull force, coil temperature, delay time, coil width on pull process, heating time, feed distance on forge process, and heating area on micro hole fabrication process were experimentally researched. Sealed by UV optical glue, a kind of T-shape combined glass micronozzle was prepared. Orderly core oil emulsion in sodium alginate solution and core oil, poly microsphere (PS) and glass microsphere microcapsules were prepared based on combined pulse dispensing with the T-shape micro-nozzle. Results showed that the T-shape combined glass micronozzle had the advantage of simple structure, low cost, good bio-chemical and optical character and the T-shape micronozzle could be used to produce multiphase liquid flowing and dispensing. It is promising to be applied wildly in other areas.

Abstract: In this paper a simple eco-friendly wet-chemical way was mentioned to synthesize gold nanoplates. The prepared of the gold nanoplates was a seedless process that carried out by mixing HAuCl₄ aqueous solution and Tannic acid (TA) solution at room temperature without the other surfactant and capping agents. The scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) have been used to characterize the shape and composition the prepared gold nanoplates. The molar ratio of HAuCl₄ and TA can control the shape and the size of gold nanoplates effectively. This research can provide a simple and eco-friendly way for the prepared gold nanoplates in aqueous solution.

Abstract: A method of synthesizing three-dimensional self-assembled multi-walled carbon nanotube (MWCNT) nanopaper on hydrophilic polycarbonate membrane was investigated. In combination with shape-memory polymer (SMP), the conductive MWCNT nanopaper facilitates the actuation in SMP composite induced by electrically resistive heating. The process is based on the very well-defined dispersion of nanotube and controlled pressure vacuum deposition procedure. The morphology and structure of the nanopaper are characterized with scanning electronic microscopy (SEM) over a wide range of scale sizes. A continuous and compact network observed from the microscopic images indicates that the MWCNT nanopaper could have highly conductive property. The experiment results show that the electrical resistivity of MWCNT nanopaper decreased as temperature increase. SMP composites recovery from a fixed benting shape to the oroginal shape under a constant DC voltage.

Abstract: Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD) were used to investigate crystallization of the Zr70Cu8Ti7Ni15 bulk amorphous alloy, the results show that the edge region of BMGs sample produces nanosize Nickel crystals using the method of the ion thinning to make the TEM sample. The quantity of nanocrystals is proportional to the time of ion thinning and they are not residual crystals in the BMGs.

Abstract: As one-dimensional GaN material has excellent physical properties, it owns a huge prospect in the field of optoelectronic devices, and nanowire is currently one of the hotspots, at home and abroad, which had already invested a considerable force into the GaN nanowires. This paper studied the growth method based on Gas Liquid Solid (VLS) mechanism using Ni as catalyst in a chemical vapor deposition (CVD) system. By scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDX) spectroscopy, transmission electron microscopy (TEM) test, we focused on the influence of temperature and pretreat on the morphology and properties of GaN nanowires. At the same time, we explored the law and gave an appropriate explanation.

Abstract: Based on EDM method combined with ultrasonic field, the effects of different electric current, impulse width, and voltage on the surface morphology of nickel microspheres were studied. The preparation condition and forming mechanism of microspheres with compact and smooth surface were investigated. The result shows that removal rate and explosion force of the electrode materials play an important role in forming microspheres, and homogeneous nucleation goes against the uniformity of the surface morphologies of microspheres.

Abstract: Porous titanium dioxide (TiO₂) nanostructure has been successfully synthesized by a modified solgel method using non-ionic triblock copolymer pluronic F-127 as surfactant template and titanylsulfate (TiOSO₄) solution as the inorganic precursor derived from the sulfuric process of Bangka-Indonesia ilmenite ore. The resulting nanostructure samples were characterized by XRD, SEM, TEM and UV-Vis spectroscopy. The results showed that porous titania particles have sphere-like shape and can be indexed as the anatase phase with average crystallite size of about 5-7 nm, narrow pore size distribution with an averange pore diameter of about 3-5 nm and band gap energy in the range of 3.10 3.16 eV.

Abstract: In the present paper, the γ-Fe₂O₃ nanoparticles have been successfully synthesized by the co-precipitation process and followed by calcination. The X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the as prepared nanoparticles. The results show that the phase structure of the nanoparticles is γ-Fe₂O₃ with the particle size ranging from 40 to 50 nm. The catalytic activity of the γ-Fe₂O₃ was investigated by decomposing the phenol in liquid phase. The results showed that γ-Fe₂O₃ has the highest catlytic activity.

Abstract: Nanometer-sized ZnO crystals with the diameter from 20 nm to 110 nm were prepared by homogenous precipitation method (HPM). The photoluminescence (PL) spectra of as-prepared nanoparticles under excitation at the wavelength of 320 nm were detected. The PL spectra were fitted with Gaussian curves, in which a good fitting consisting of six Gaussian peaks was obtained. We observed that the multi-peak centers do not change much, while the relative amplitude of Gaussian combination to the band-to-band emission decreases rapidly with the increased grain size. It shows that the broadband emission at the lower energy is associated with the surface states.

Abstract: The potential use of ZnO nanoparticles for cell labeling application has been improved over past several years. Focusing to overcome the tendency of the nanoparticles to aggregation, in this work ZnO nanoparticles have been synthesized by using surfactant-assisted precipitation method. The samples were then characterized by using XRD and UV-Vis Spectroscope. The results showed that the presence of surfactant could help controlling the crystallite size to become smaller (4.02 nm) as compared to the conventional precipitation method (9.45 nm). ZnO nanoparticles that had been coated by the surfactant was then re-coated again by silica shell to form ZnO@SiO2 core-shell. The presence of F-127 coating on the surface of the nanoparticles made the dispersion and the stability of crystallite size better in various encapsulation pH value (4.04 4.32 nm). The band gap energy of the ZnO nanoparticles (3.145 3.085 eV) also showed a good correlation with the crystallite size (4.02 10.38 nm). Therefore, the resulting ZnO@SiO2 core-shell in the present work are potential to be used in cell labeling application.