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Electron Emission from Robust CNTs Grown by Resist-Assisted Patterning
박규창,이창석,류재황,임한얼,민경우,정일옥,S. Manivannan,장진,김기서 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5
We developed novel carbon-nanotube field-emitter arrays (CNT-FEAs) with a resist-assisted patterning process using dc-plasma enhanced chemical vapor deposition (PECVD). Through this method, we obtained a CNT very strongly bonded to the substrate. The CNTs were grown at -600 V bias to the substrate electrode and a +300 V bias to the mesh grid, being placed 10 mm above the substrate holder electrode. The structure and the electrical properties of the CNTs were strongly related to the growth time. The length was decreased after 80-minute and the diameter increased with the growth time. The electron emission current increased with growth time. The growth mechanism, the electron emission characteristics and the mechanical robustness are discussed. We developed novel carbon-nanotube field-emitter arrays (CNT-FEAs) with a resist-assisted patterning process using dc-plasma enhanced chemical vapor deposition (PECVD). Through this method, we obtained a CNT very strongly bonded to the substrate. The CNTs were grown at -600 V bias to the substrate electrode and a +300 V bias to the mesh grid, being placed 10 mm above the substrate holder electrode. The structure and the electrical properties of the CNTs were strongly related to the growth time. The length was decreased after 80-minute and the diameter increased with the growth time. The electron emission current increased with growth time. The growth mechanism, the electron emission characteristics and the mechanical robustness are discussed.
박규창,윤현식,유제황,장진,문종현,임성훈 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.6
We report on the electron emission properties of carbon nanotubes grown in holes with a triodetype direct-current (DC) plasma-enhanced chemical vapor deposition (PECVD) system. In this study, the growth of CNTs in gate holes for field-emission displays was performed by using a silicon-nitride (SiNx) capping layer on a Ni catalyst. The CNTs grown with a 3 μm hole pattern show the highest electron emission and the lowest turn-on field properties. The highest emission current of CNTs grown with a 3 μm hole pattern appears to be due to non-field screening by neighboring CNTS. Also, we can grow CNTs with a gate-hole pattern and measure the electron emission properties by using a triode structure. Two CNTs can be grown in gate holes with a 3 μm hole diameter. The electron emission anode current density is 0.9 μA/cm2 at a 35 V gate bias and a 2.0 kV anode bias.p
고성능 액체 크로마토그래피에 의한 Costus speciosus중 Diosgenin의 분석법
朴奎昌,金宅濟 慶熙大學校 1985 論文集 Vol.14 No.-
Diosgenin in Costus specious was analysed by high-performance liquid chromatographic (HPLC) Technique. The dried, powdered sample was refluxed with the mixed solution of 3N HCl and xylene (1:1) at 95-100℃ for 4 hours. The residue obtained from the xylene layer was acetylated and then injected into HPLC. HPLC was performed using a set of four of the reversed-phase column (30㎝×3.9㎜ i.d., μ-Bondapak C_18, 10㎛) Connected in series. The solvent system was tetrahydrofuran - n - hexane-acetonitrile (1:2:7). Au UV detector was used at a wavelenght of 210㎚.
Purification and Preparation of Single-Walled Carbon Nanotube Films
박규창,S. Manivannan,정일옥,류재황,이창석,장진,김기서 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5
We describe a simple process for the removal of metal catalysts and the dispersion of single-walled carbon nanotubes (SWNTs) in aqueous and organic solvents without damaging the structure of the nanotubes. The metal catalyst was removed by using a sodium hydroxide (NaOH) - ethyl alcohol (EtOH) solution. Dispersion of purified nanotubes was accomplished by using a polymer wrapping functionalization. Raman and scanning electron microscope analyses were performed to confirm the purity and the dispersion of the treated tubes. The bundle size of the dispersed SWNTs was elucidated using the atomic force microscopy technique and the size was measured as 2 - 5 nm. Transparent and conducting carbon nanotube films were prepared on glass substrates by using a spin-coating method. Optical transmission and sheet resistance measurements showed that the randomly-oriented, dispersed nanotubes film had an average sheet resistance of 974 Ω/□ and a at optical transmission of ∽77 % at 600 nm. In this simple and scalable process, the sheet resistance and the optical transmission of the film were controlled by using the number of coatings and the concentration of the solution. We describe a simple process for the removal of metal catalysts and the dispersion of single-walled carbon nanotubes (SWNTs) in aqueous and organic solvents without damaging the structure of the nanotubes. The metal catalyst was removed by using a sodium hydroxide (NaOH) - ethyl alcohol (EtOH) solution. Dispersion of purified nanotubes was accomplished by using a polymer wrapping functionalization. Raman and scanning electron microscope analyses were performed to confirm the purity and the dispersion of the treated tubes. The bundle size of the dispersed SWNTs was elucidated using the atomic force microscopy technique and the size was measured as 2 - 5 nm. Transparent and conducting carbon nanotube films were prepared on glass substrates by using a spin-coating method. Optical transmission and sheet resistance measurements showed that the randomly-oriented, dispersed nanotubes film had an average sheet resistance of 974 Ω/□ and a at optical transmission of ∽77 % at 600 nm. In this simple and scalable process, the sheet resistance and the optical transmission of the film were controlled by using the number of coatings and the concentration of the solution.
朴奎昌,李垣,池璟淑,李栽成 慶熙大學校 1979 論文集 Vol.9 No.-
Thirty nine samples of the underground water in the region 2 km away from Baik Am hot spring at On Jung Ri, Wool Jin Goon, Kyung Book Province, were collected and analyzed from August 23 to August 24, 1979. Fluoride contents in the samples of the underground water were 0.02-0.15 ㎎/ℓ and except those of No. 18 and No. 40 which contain 1.15 ㎎/ℓ and 0,37 ㎎/ℓ respectively. It is reasonable to suppose that the high COD values of the samples of the underground water are produced mainly by the decomposition of the organic substances because they contains great amounts of Cl^-, Na^+ and Mg^(2+).