Search Result of "พิเชษฐ ลิ้มสุวรรณ"

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ที่มา:วิทยานิพนธ์ ปริญญาโท (จาก: บัณฑิตวิทยาลัย และ สำนักหอสมุด มก.)

หัวเรื่อง:การศึกษาและการสร้างคาร์บอนไดออกไซด์เลเซอร์ ชนิดกระตุ้นตามขวางที่ความดันบรรยากาศ

ผู้เขียน:Imgนพพร รัตนช่วง

ประธานกรรมการ:Imgดร.ณัฐณรัณ (สุปรียา) ตรีวิจิตรเกษม, รองศาสตราจารย์

กรรมการวิชาเอก:Imgพิเชษฐ ลิ้มสุวรรณ

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Structures and Optical Properties of TiO2 Thin Films Deposited on Unheated Substrate by DC Reactive Magnetron Sputtering)

ผู้เขียน:ImgNirun Witit-anun, ImgPrasertsak Kasemanankul, ImgSurasing Chaiyakun, Imgพิเชษฐ ลิ้มสุวรรณ

สื่อสิ่งพิมพ์:pdf

Abstract

Titanium dioxide thin films (TiO2) were deposited on unheated substrate on a glass slide and Si-wafer by the DC reactive magnetron sputtering method at different total pressures. The crystal structure, surface morphology and optical transmittance were characterized by X-ray diffractometer, atomic force microscopy and UV-VIS-NIR spectrophotometer, respectively. The deposited films were transparent and the thickness was about 133-168 nm. XRD results showed that all samples possessed a polycrystalline structure and changed from the mixed phase of anatase and rutile, to rutile phases, as the total pressure decreased. An increase in the film’s roughness was observed with increasing sputtering pressure. The optical transmission measurements revealed that the mixed phases of anatase and rutile had higher transmittance than the pure rutile phase. The refractive index, in the visible spectrum was relatively high, while the energy band gap was found to be 3.25 eV.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 043, Issue 4, Oct 09 - Dec 09, Page 340 - 346 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Electron Spin Resonance (ESR) and Optical Absorption Spectra of a Manganese Doped Soda-Lime-Silicate Glass System)

ผู้เขียน:ImgNattapon Srisittipokakun, ImgChittra KedKaew, ImgJakrapong Kaewkhao, ImgTreedej Kittiauchawal, Imgเขมฤทัย ถามะพัฒน์, Imgพิเชษฐ ลิ้มสุวรรณ

สื่อสิ่งพิมพ์:pdf

Abstract

A (65-x)SiO2:10CaO:25Na2O:xMnO2 glass system with 0 ? x ? 0.5 mol% was prepared and investigated by X-ray diffraction, optical absorption and ESR spectroscopies. The XRD pattern of undoped glass confirmed the formation of an amorphous vitreous structure. The optical absorption spectra exhibited a predominant broad band around 500 nm and its increase was clearly observed from 0.1 mol% of MnO2. This band corresponded to an allowed transition from 5Eg5T2g, of Mn3+ ions. When the MnO2 concentration was increased, the absorption band due to Mn3+ ions dominated. The ESR spectra results exhibited resonance signals at g ? 2.0 with a sextet of hyperfine lines and less intensity at g ? 4.3. The group of hyperfine lines at g ? 2.0 represented Mn2+ ions in octahedral symmetry. However, these lines were broader and disappeared for higher MnO2 concentrations. This behavior indicated the reduction of Mn2+ ions in the glass system as the concentration of MnO2 was increased by increasing the Mn3+ ions.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 043, Issue 5, Dec 09 - Dec 09, Page 360 - 364 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Structures and Optical Properties of TiO2 Thin Films Deposited on Unheated Substrate by DC Reactive Magnetron Sputtering)

ผู้เขียน:ImgNirun Witit-anun, ImgPrasertsak Kasemanankul, ImgSurasing Chaiyakun, Imgพิเชษฐ ลิ้มสุวรรณ

สื่อสิ่งพิมพ์:pdf

Abstract

Titanium dioxide thin films (TiO2) were deposited on unheated substrate on a glass slide and Si-wafer by the DC reactive magnetron sputtering method at different total pressures. The crystal structure, surface morphology and optical transmittance were characterized by X-ray diffractometer, atomic force microscopy and UV-VIS-NIR spectrophotometer, respectively. The deposited films were transparent and the thickness was about 133-168 nm. XRD results showed that all samples possessed a polycrystalline structure and changed from the mixed phase of anatase and rutile, to rutile phases, as the total pressure decreased. An increase in the film’s roughness was observed with increasing sputtering pressure. The optical transmission measurements revealed that the mixed phases of anatase and rutile had higher transmittance than the pure rutile phase. The refractive index, in the visible spectrum was relatively high, while the energy band gap was found to be 3.25 eV.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 043, Issue 5, Dec 09 - Dec 09, Page 340 - 346 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Determination of U, Th and K in Sediments and Fossil Collected from Mae Moh Mine Using Gamma-Ray Spectrometry and Neutron Activation Analysis (NAA))

ผู้เขียน:ImgTidarut Vichaidid, ImgThongchai Soodprasert, ImgNatnalin Sastri, ImgChutima Oopathum, Imgพิเชษฐ ลิ้มสุวรรณ

สื่อสิ่งพิมพ์:pdf

Abstract

The annual environmental dose in sediment and fossil shells matrices, collected from Mae Moh mine, Lampang province, Northern Thailand has been determined by using gamma spectrometry together with neutron activation analysis technique (NAA). This analysis technique was adopted by activating NBS standard reference materials (NBS SRM 2709: San Joaquin Soil) and sediment matrices at the same condition before measuring them at the specific time schedule. High Purity Germanium (HPGe) well type detector and spectrometer were calibrated to get efficiency ratio by reference standard sources. Most of natural radioactive elements are members of uranium, thorium and from non series nuclides, mainly potassium. The result concentration of uranium, thorium, and potassium in samples can be achieved by this technique and found to be in the range of 0.02 to 3.05 ppm, 0.04 to 11.00 ppm, and 0.01 to 1.53% respectively. The annual environmental dose is between 87-3000 mGy, depended on type of metrics, and can be specifically calculated and used for dating around the Middle Miocene time scale.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 042, Issue 5, Dec 99 - Dec 99, Page 333 - 339 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effect of Annealed Temperatures on the Morphology of TiO2 Films)

ผู้เขียน:Imgวีรนุช แก้ววิเศษ, ImgWandee Onreabroy, Imgพิเชษฐ ลิ้มสุวรรณ

สื่อสิ่งพิมพ์:pdf

Abstract

Titanium dioxide (TiO2) films were prepared by dip-coating method on the glass slide substrates at room temperature. The TiO2 solution was synthesized from titanium tetraisopropoxide:Ti(OC3H7)4 in isopropanol at molar ratio 1:4. This research focus on the surface and roughness of TiO2 films which were characterized by atomic force microscopy (AFM). In the first experiment, TiO2 films were deposited at 1, 5, 10 and 15 layers and annealed at 500 ?C. Then, the films which were deposited for 15 layers were chosen to be annealed at different temperatures of 300, 350, 400, 450 and 500 ?C. The results showed that, when the number of film layers increased, the grain sizes were clearly observed. The grain size depended on the annealing temperature. It was found that at the temperature of 300 to 500 ?C, the grain sizes were 30-40 nm.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 042, Issue 5, Dec 99 - Dec 99, Page 340 - 345 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Measurement of a Thermal Expansion Coefficient for a Metal by Diffraction Patterns from a Narrow Slit)

ผู้เขียน:ImgPiyarat Bharmanee, Imgเขมฤทัย ถามะพัฒน์, ImgPramot Satasuvon, Imgพิเชษฐ ลิ้มสุวรรณ

สื่อสิ่งพิมพ์:pdf

Abstract

In this work, we made an effort to determine linear coefficient of thermal expansion of metal using single-slit diffraction. An aluminium strip was used as sample. The design of the apparatus for this method allows for the width of a single slit to increase by the same amount as the thermal expansion of a length of a strip or a rod of a material. The increase in the slit width, hence the linear expansion, can be determined by measuring the fringe width. A He-Ne laser with a wavelength of 632.8 nm was used to obtain a diffraction pattern for the single slit. The value of the linear coefficient of thermal expansion of the material can then be calculated using the principle knowledge of diffraction equation and thermal expansion. The experimental result was found that the linear coefficient of thermal expansion of aluminium is 22.512 ? 10-6 (C?)-1, giving a 2.545 % error.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 042, Issue 5, Dec 99 - Dec 99, Page 346 - 350 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Influence of Annealing Temperature on the Properties of ITO Films Prepared by Electron Beam Evaporation and Ion-Assisted Deposition)

ผู้เขียน:ImgArtorn Pokaipisit, ImgMati Horprathum, Imgพิเชษฐ ลิ้มสุวรรณ

สื่อสิ่งพิมพ์:pdf

Abstract

Indium tin oxide (ITO) films were deposited on glass substrates by electron beam evaporation and ion-assisted deposition. Evaporation material source was 90 wt% In2O3 and 10 wt% SnO2 (purity of 99.99%). The ITO films were annealed in the air at 200, 250, 300 and 350 ?C for 1 h. The structures, electrical and optical properties of ITO films were investigated. The deposited films were analyzed by X-ray diffractometer, four-point probe method and UV-NIR spectrophotometer. It was found that the lowest resistivity (2.25 ? 10-4 ?-cm) and highest optical transmittance (83%) of ITO films were obtained at the annealing temperature of 300 ?C. The grain size increased from 36.69 to 46.73 nm with increasing annealing temperature.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 042, Issue 5, Dec 99 - Dec 99, Page 362 - 366 |  PDF |  Page 

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