Papers by Author: Artorn Pokaipisit

Abstract: In the manufacturing of slider, the final step is a dicing process of the rowbars into individual slider. However, in all slider separation processes seem to affect the curvature of the slider air bearing surface (ABS). As a result, the change in ABS crown and camber which can significantly affect the fly height of the slider. This paper investigates the influence of three types of dicing process, with the same feed rate and cutting speed, on the ABS curvature.

Abstract: The aim of the present study was to investigate the organic and inorganic compositions of enamel and dentine after Er:YAG laser irradiation using Fourier-transform Raman spectroscopy (FT-Raman). The enamel and dentine of extracted human teeth were irradiated by Er:YAG laser at an energy density of 29.7 J/cm2. The organic and inorganic components were evaluated from Raman spectra of untreated and laser-treated of extracted human teeth. The results showed that the Raman intensity ratio of the carbonate peak (1067 cm-1) to the phosphate peak (957 cm-1) and the organic peak (2940 cm-1) to the phosphate peak of enamel and dentine decreased after laser irradiation. Therefore, laser treatment can reduce the organic and inorganic components of human enamel and dentine.

Abstract: Ultra-thin Al films were deposited with different deposition times on silicon wafer and copper grid by dc magnetron sputtering. The sputtering power of 200 watt and Ar flow rate of 20 sccm were used to prepare the films. The deposition times were 40, 120 and 240 second, respectively. The deposited Al films were, then, left in the air under the humidity of 60% for 20 days. The crystal structure of ultra-thin Al films deposited on silicon wafer and copper grid were investigated by glazing x-ray diffraction (GXRD) and transmission electron microscopy (TEM), respectively. The XRD results show that after the ultra thin Al films were exposed to the air, the Al was oxidized and the Al2O3 was formed at room temperature. In addition, Al deposited for 120 and 240 second can form polycrystalline of -Al2O3 with preferred orientations of (110) and (311) planes. The TEM images show that the particle size of -Al2O3 was about 8.5 nm for deposited time of 120 second. Moreover, the spectroscopic ellipsometry (SE) data and simulation model of Bruggemann effective medium approximation (BEMA) was used to determine the volume fraction of Al2O3.

Abstract: Glasses with composition xBi2O3:(60-x)BaO:40B2O3 with 10£x£50 (in mol%) have been prepared using the normal melt-quench technique. The optical absorption spectra of the glasses have been recorded in the wavelength range 400-700 nm. The fundamental absorption edge has been identified from the optical absorption spectra. The values of optical band gap are decreased with the addition of Bi2O3. The density and molar volume studies indicated that Bi2O3 in these glasses is acting partly as network modifier and partly as network former.Values of the theoretical optical basicity are also reported and discuss in term of oxide ion polarizability.

Abstract: The influence of annealing temperature on the optical and electrical properties, nanostructure and surface morphology of ITO thin films prepared by ion-assisted electron beam evaporation on the glass substrates has been studied. The resistivity and transmittance spectra were measured by a four-point probe method and spectrophotometer, respectively. The nanostructure and surface morphology were examined by X-ray diffractometer and atomic force microscopy. The results show that the ITO thin films with a thickness of 200 nm is amorphous. The crystallite size and optical band gap of ITO thin films increased after annealing in vacuum at different temperatures from 200 to 350 oC. At 350 oC, high quality crystalline thin films with a crystallite size of about 30 nm were obtained. The average optical transmittance was 84% in the visible range (400-700 nm) and the resistivity of 1.34 × 10-4 W-cm was obtained at a temperature of 350 oC.