Search Result of "พิเชษฐ ลิ้มสุวรรณ"

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นาย พิเชษฐ์ ลิ้มสุวรรณ

ที่ทำงาน:ภาควิชาอนุรักษ์วิทยา คณะวนศาสตร์ บางเขน

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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 : Effect of Films Thickness on the Properties of ITO Thin Films Prepared by Electron Beam Evaporation)

ผู้เขียน:ImgArtorn Pokaipisit, ImgMati Horprathum, Imgพิเชษฐ ลิ้มสุวรรณ

สื่อสิ่งพิมพ์:pdf

Abstract

Indium tin oxide (ITO) thin films were prepared on glass slide substrates at various thicknesses by electron beam evaporation (e-beam) from a tablet of In2O3 and SnO2 (9:1). The ITO thin films were fabricated at substrate temperatures of 150 ?C, deposition rate of 2 ?/s and oxygen flow rate of 12 sccm. The structure, surface morphology, electrical and optical properties of ITO thin films were investigated. The structure and surface morphology of films were monitored by using X–ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The optical transmittance and sheet resistance of ITO thin films were measured by spectrophotometer and four-point probe. It was found that transmittance and sheet resistance of ITO thin films on glass slide decreased as film thickness increased from 200 nm to 700 nm. The transmittance spectra in the visible region (400-700 nm) and the sheet resistance decreased from 76.63% to 57.89% and from 16 ?/sq. to 4 ?/sq., respectively, with increasing the films thickness.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 041, Issue 5, Jan 07 - Dec 07, Page 255 - 261 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : The Color Change of Natural Blue Sapphires by Heat Treatment)

ผู้เขียน:ImgTreedej Kittiauchawal, Imgพิเชษฐ ลิ้มสุวรรณ

สื่อสิ่งพิมพ์:pdf

Abstract

This research aimed to investigate the effects of heat treatment on color and clarity of blue sapphires. The blue sapphires were heated at sequentilly increasing temperature of 1300, 1400, 1500 and 1600 ?C in nitrogen atmosphere. Each temperature, the samples were treated for 12 hours, before and after heat treatment at each temperatures, the color and clarity were measured by spectrophotometer. It was found that, when blue sapphires were heated at high temperatures, the color of the untreated sapphire crystal changed to darker blue at higher temperatures. Whereas, the clarity of all samples were not significantly found in the temperature range of 1300 -1600?C

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 041, Issue 5, Jan 07 - Dec 07, Page 262 - 266 |  PDF |  Page 

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ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : A Biomonitoring Study: Trace Metals in Amusium pleuronectes Shell from the Coastal Area of Chon Buri Province)

ผู้เขียน:Imgวิเชียร ศิริพรม, Imgพิเชษฐ ลิ้มสุวรรณ

สื่อสิ่งพิมพ์:pdf

Abstract

The objective of the present study was to conduct a preliminary investigation of pollution in the coastal area of Chon Buri province environment with a focus on heavy metals in Amusium pleuronectes shell. An energy Dispersive X-ray Fluorescence (EDXRF) spectrometer was used to determine the composition of mineral and levels of the heavy metals, gold (Au), zinc (Zn), lead (Pb), chromium (Cr), iron (Fe) and manganese (Mn) in the Amusium pleuronectes shell. The results showed that the highest to lowest accumulated metals are Fe, Mn, Cr, Zn, Pb and Au, respectively. The crystal structure and microstructure of the shells were studied by x-ray diffraction (XRD) technique and IR spectroscopy, respectively. The XRD patterns and IR spectrum revealed that the samples is made of a mixture phase of aragonite and calcite. In addition, the Electron Spin Resonance Spectroscopy (ESR) was used to study the ions in the samples. It was found that the samples consists of Mn2+ ions in the calcite lattice of the Amusium pleuronectes shell.

Article Info
Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 043, Issue 5, Dec 09 - Dec 09, Page 141 - 145 |  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 : 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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