Papers by Keyword: Immersion Method

Abstract: 316L stainless steel fiber felt was used as raw material. Sound absorption properties of the porous materials before/after corrosion were measured through the double pipe microphone impedance method. The law of the sound absorption properties was discussed also. In addition, the microstructure of the porous materials was observed by SEM. Some results are concluded as follows: when the hydrochloric acid (HCL) concentration is 1wt%, the sound absorption coefficient of the porous materials before/after corrosion is invariable generally. When the HCL concentration is 10wt%, the one after corrosion is higher than before corrosion, about 0.2 (4000~6000Hz), due to the corrosion pits at the face of the fibers.

Abstract: Cotton coated titanium dioxide, TiO₂ was prepared by using immersion method. Three samples with different concentration which are 0.2 M, 0.5 M and 0.6 M of TiO₂ solution with fixed value of temperature and time immersion has been used in this project. Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and Ultraviolet/Visible (UV-Vis) Spectrophotometer have been used to determine the properties of samples. The surface morphology of the cotton, crystalline phase of TiO₂ particles deposited on the cotton fiber and the amount of the TiO₂ particles dispersed in the water has been investigated. The existence of TiO₂ on the cotton fiber was identified by using SEM and XRD where the immersion method that has been used in this project contributed to the agglomerated TiO₂ particles on the surface of cotton fiber. None of the samples showed the formation of anatase crystalline phase of TiO₂ particle and UV-Vis showed the released of TiO₂ in the water was higher in the first immersion and decreased exponentially for the second, third and fourth immersion.

Abstract: In this paper, the physical characteristics and memristive behavior of TiO₂ nanostructures grown at different substrate positioning by wet chemical solution were investigated. TiO₂ thin film as a seed layer for TiO₂ nanostructures growth was first deposited on ITO-coated substrate by RF magnetron sputtering method. TiO₂ nanostructures were then grown by immersing the TiO₂ thin film/ITO/glass sample in 10M NaOH solution at 80 °C while studying the effect of the substrate position to the nanostructure growth and thus its memristive behavior. Characterization on the growth morphology of TiO₂ nanostructures was observed using scanning electron microscopy (FESEM). The current-voltage (I-V) measurement of the device was investigated for its memristive behavior. Different growth morphology of TiO₂ nanostructures was observed at different substrate positioning. It was found that sample immersed with TiO₂ layer facing down the vessel result in the formation of TiO₂ nanowires and exhibit better memristive behavior.

Abstract: TiO₂ nanostructures were successfully grown on TiO₂ thin film by solution-based method at low temperature. TiO₂ thin film as a seed layer for the nanostructures growth was deposited on ITO substrate by RF magnetron sputtering method at 40 and 60 nm thicknesses. Then the TiO₂ nanostructures were synthesized on the samples by keeping them floating with TiO₂ layer facing down the vessel in 10M NaOH solution at 80°C for 45 min. Effect of seed layer thickness to the growth of TiO₂ nanostructure and its memristive behaviour were investigated. Surface morphology and current-voltage measurement for its memristive behaviour were measured by FESEM image and Keithley 4200 semiconductor characterization system. It was found that 60 nm-TiO₂ thin film result in the formation of dandelion-like morphology of TiO₂ nanowires and gives better memristive behavior with larger switching loops when positive voltage was applied to the sample.

Abstract: The optical and structural properties of Zinc Oxide (ZnO) nanostructures is prepared by sol-gel immersion method at different temperature on Porous Silicon (PSi) Substrates. PSi is produced from the Si by using electrochemical etching process. The ZnO solution is prepared by using the sol-gel immersion method. Parameters such as different deposition time were studied. The optical properties of ZnO Nanostructures will be characterized by using PL and SEM. The structural properties of ZnO Nanostructures will be characterized by using XRD. The result of investigation show that the growth of ZnO nanostructures improving as the deposition temperature increase.

Abstract: ZnO nanorods were prepared by immersion method deposited onto Silicon (Si) and gold-seeded Si (Au/Si) substrate. The annealing temperatures were varied from 400, 500 and 600 °C. The effect of annealing temperature on the surface morphology and photoluminescence characteristics was investigated. The samples were characterized by Field Emission Scanning Electron Microscope (FESEM) to study their morphology and structural properties while the optical properties were characterized at room temperature using Photoluminescence Spectroscope. The shape of ZnO showed growth of nanorods with hexagonal shape. As the annealing temperature increased, the morphology study indicates that particle size of ZnO decreased while the crystallinity increases. The structures has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors.

Abstract: ZnO hexagonal rod structure were prepared by immersion method deposited onto Si (Si/ZnO) and gold-seeded Si substrate (ZnO/Au/Si). The annealing temperatures were varied from 400, 500 and 600 °C. The effect of annealing temperature on the surface morphology and photoluminescence characteristics was investigated. The samples were characterized by Field Emission Scanning Electron Microscope (FESEM) to study their morphology and structural properties while the optical properties were characterized at room temperature using Photoluminescence Spectroscopy. The shape of ZnO showed growth of rods with hexagonal shape. As the annealing temperature increased, the morphology study indicates that diameter size of ZnO decreased while the crystallinity increases. The structures has high surface area, is a potential metal oxide nanostructures to be develop for optoelectronic devices and chemical sensors.

Abstract: ZnSnO₃ thin film was deposited at different deposition time (0.5 h, 2 h, 4 h and 6 h) using sol-gel immersion method and the electrical, optical and structural properties of this film was investigated. This research involved the preparation of nanostructured ZnO thin film by using RF magnetron sputtering, preparation of ZnSnO₃ sol-gel solution, metal contact deposition and characterization of humidity sensor. The thin film was characterized using current-voltage (I-V) measurement (Keithley 2400) and field emission scanning electron microscopy (FESEM) (JEOL JSM 6701F) for electrical and structural properties respectively. The sensor was characterized using I-V measurement in a humidity chamber (ESPEC SH-261) and the chamber has been set at room temperature with varied relative humidity (% RH), in the range of 40-90% RH. The film prepared with a deposition time of 2 h shows better sensitivity for humidity sensor. The FESEM investigation shows that crystal size increases with the increasing deposition time.

Abstract: Nano-Ni(OH)₂ doped with special elements were prepared by supersonic co-precipitation method. Complex electrodes were prepared by immersion method and handwork method by mixing 8wt.% nickel hydroxides with commercial micro-size spherical nickel as the positive material of Ni-MH battery. The electrochemical performance and cyclic character affected by different electrodes’ making methods were characterized in this article. The result indicates that the discharge capacities of IM electrodes (IM electrodes mean electrodes made by handwork method) are higher than that of HM electrodes (HM electrodes mean electrodes made by handwork method). Furthermore, IM electrodes have better reversibility and higher charge efficiency than HM electrode, and lower charge potential and higher discharge plateau were also observed for IM electrodes. It's worth noting that the phenomenon is more obvious at high charge/discharge rate. When the discharge rate is 0.5C，the discharge capacity of IM electrode is higher 67.1 mAh•g ^-1 than that of HM electrode.

Abstract: A new type composite catalyst of V₂O₅ comprising Co-Mo/V₂O₅ was prepared by immersion method and characterized by XRD. The characteristic peaks of CoMoO₄(2θ=28.51°) and CoMoO₃(2θ=18.06 °)are both observed in the XRD patterns of Co-Mo/V₂O₅(5%, 20%) catalysts. The oxidation of cyclohexane with hydrogen peroxide was used as a probe reaction to investigate the effects of some conditions, such the sort and volume of solvent, catalyst amount, oxidant amount, reaction temperature and time, on reaction. Using 0.5 ml of cyclohexane, 10 ml of acetonitrile, 3 ml of hydrogen peroxide and 0.03 g of catalyst at a reaction temperature of 55°C for 3 h, the cyclohexane conversion was 32.3% and the total selectivity to cyclohexanol and cyclohexanone was 100%.