• Korean Journal of Materials Research
• /
• v.7 no.8
• /
• pp.679-686
• /
• 1997

P-type Si(111)기판 위에 3C-SiC박막 성장시 TMS(tetramethylsilane)유량, 반응온도, 반응압력, 가스공급방법등 다양한 성장변수에 따른 박막의 결정성변화를 연구하였다. 증착된 막은 모두 (111)방향성만을 나타내었고, free Si, C의 존재는 관찰할 수 없었다. TMS 유량 0.5 sccm에서, 1100-120$0^{\circ}C$의 반응온도에서 , 반응압력 12-50Torr 조건에서 비록 dislocation과 twin등이 발결되었으나 단결정 3C-SiC 박막을 성장시킬 수 있었으며, 박막의 결정성은 기판에 흡착된 Si-종과 C-종이migration할 수 있는 시간과 에너지에 크게 영향 받음을 확인할 수 있었다. 또한 SiC/Si계면에서 carbonization공정에서 관찰되는 것으로 알려진 void를 관찰할 수 있었으며, 이러한 void의 발생은 기체공급방법을 달리함으로서 제거할 수 있음을 확인할 수 있었다.

• Journal of the Korean Magnetics Society
• /
• v.3 no.3
• /
• pp.234-240
• /
• 1993

The water-based magnetic fluids were prepared with the synthesized ultrafine magnetite, dodecanoic acid as surfactant. Characteristics of synthesized ultrafine magnetite were investigated with X-ray Diffraction Pattern, Transmission Electron Microscope, Vibrating Sample Magnetometer and BET analysis. Dispersion characteristics of water-based magnetic fluids were investigated in relation to amounts of surfactant, pH and solid content.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.5 no.2
• /
• pp.122-128
• /
• 1995

Sintered bodies were prepared from ${\alpha} - Al_2O_3/SiO_2$ composite powders which each alumina particles were surrounded by silica particles and investigated the mullitization behavior on the process of reaction - sintering. Mullitized reaction was started by formation of amorphous aluminosilicate inter - layer and proceeded by diffusion of alumina through this inter-layer. The growth of mullite was happened along the surface of alumina and controlled by the rate of diffusion.

• Journal of the Korean Chemical Society
• /
• v.18 no.6
• /
• pp.391-399
• /
• 1974

Corrosion and passivation of metallic cobalt was studied by means of electrochemical experiments including potentiostatic and galvanostatic measurements and cyclic voltammograms. The mechanisms of active dissolution and passivation of cobalt at the metal/borate buffer solution interface are deduced from the Tafel slope, pH dependence of the Flade potential, and dissolution kinetic data. Hydroxyl group adsorbed on cobalt surface seems to participate in surface oxidation and formation of the passive layer. The growth kinetic data as measured by the current density suggests a mechanism in which the growth of the passive layer is determined by field-assisted transport of ions through the layer. Thickness of the passive layer was estimated by coulometry to be about 10${\AA}$ at the lowest passive potential and to grow gradually with anodic potential to about 20${\AA}$.

• Journal of the Korean Chemical Society
• /
• v.39 no.1
• /
• pp.57-65
• /
• 1995

The electrochemical reduction of methylene blue (MB) in 1.0${\times}$10-2 M KNO3 aqueous solution was investigated by direct current (DC), differential pulse (DP) polarography, cyclic voltammetry (CV) and controlled potential coulometry (CPC). The electrode reduction of melthylene blue was processed CE reaction mechanism by two electrons transfer at the first reversible wave (- 0.18 volts vs. Ag/AgCl). MB was strongly adsorbed on the stationary mercury electrode and the reduction product of conptrolled potential electrolysis was rapidly auto-oxidized in air to the original methylene blue. Upon the basis of interpretation of cyclic voltammogram with pH change, possible CE electrode reaction mechanism was suggested.

• Journal of the Korean Applied Science and Technology
• /
• v.16 no.1
• /
• pp.59-65
• /
• 1999

For a cosmetic plant wastewater containing surfactants of high concentration, adsorption treatment by granular activated carbon(GAC) having different pore size distribution was studied. Three sorts GACs were used and regenerated afterwards with methanol. Experiments were composed of batch process and column test for both virgin and regenerated GACs. Following conclusions were drawn from the study: Methylene blue activating substance(MBAS) adsorption data from the batch tests for three GACs are described well by BET isotherm and Freundich isotherm. Simulation with the BET isotherm shows that maximum adsorption appears to be affected not only by specific surface area but also by pore size distribution. Maximum adsorption from the BET isotherm for MBAS appears to diminish as the number of reactivation increases. The diminishing ratio of maximum adsorption appears to decrease as the pore size decreases. Recovery ratio of the methanol by vacuum evaporation from the spent methanol ranges from 95% to 97%.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.7 no.1
• /
• pp.1-18
• /
• 1979

인삼(人蔘)사포닌으로 처리(處理)한 모발(毛髮)의 인장강도(引張强度)와 신장도(伸張度)를 collagen 가수분해물(加水分解物)로 처리한 모발(毛髮)과 비교(比較)하였다. 모발(毛髮)에 인삼(人蔘)사포닌 흡수량(吸收量)은 high speed liquid chromatography로 측정(測定)하였으며 liquid scintillation counter로 확인(確認)하였다. 모발(毛髮)에 collagen 가수분해물(加水分解物)의 흡수량(吸收量)은 모발(毛髮)을 collagen 가수분해물(加水分解物) 용액(溶液)속에 침적(沈積)시켰을 때 처음 30분(分) 동안은 많은 량(量)의 흡착(吸着)이 일어났으나 1시간(時間) 경과후(經過後)부터는 더 이상(以上)의 증가(增加)는 보이지 않았다. 이와는 반대(反對)로 인삼(人蔘)사포닌의 경우(境遇)는 침적시간(沈積時間)의 증가(增加)에 비례(比例)하여 흡수량(吸收量)의 증가(增加)를 나타내었다. 실험결과(實驗結果)는 인삼(人蔘)사포닌이 collagen 가수분해물(加水分解物) 보다 모발(毛髮)에 더욱 효과적(效果的)임을 보여 주었고, 그리고 인삼(人蔘)사포닌의 모발(毛髮)에 대(對)한 흡수(吸收)와 인장강도(引張强度)의 증가(增加)는 모발(毛髮)의 strain-stress곡선(曲線)과 인삼(人蔘)사포닌의 계면활성(界面活性)에 의(依)해 설명(說明)하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.6 no.4
• /
• pp.648-662
• /
• 1996

Electrode surface reaction on glassy carbon and synthesized graphite (PVDF mixed graphite) in sulfuric acid solution is investigated by impedance spectroscopy at cyclic polarization. The redox peak, which may be due to the change of chemical adsorped functional group on electrode surface or oxidation and reduction of oxygen, is represented on glassy carbon and graphite electrode in potentio-dynamic current curve. The oxidation and reduction of these surface functional group on glassy carbon and PVDF mixed graphite have a major affect on the impedance spectrum and Faraday impedance parameter at cyclic polarization.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.36 no.2
• /
• pp.93-97
• /
• 2010

In this study, cationic guar polymer was selected from many cationic polymers currently using in shampoo and then was newly developed having 0.7 % above of nitrogen content and 190~200 cps of viscosity through various performance measurements. Wet combing ability, polymer substantivity, silicone deposition and panel test were evaluated for performance measurements. Cationic guar polymer that was invented from this study can optimize conditioning effects in shampoo.

• Journal of the Korean Applied Science and Technology
• /
• v.15 no.1
• /
• pp.79-90
• /
• 1998

One of the objectives of this study were to develop a process for manufacturing activated carbons from agricultural by-products(rice shells and saw dust) and another is to measure the iodine number, ash content and removal ratio of COD. The other is to compare those values with those of commercialized activated carbons. Agricultural by-products based activated carbons were manufactured through the steam-reaction method. A rotary kiln type furnace was used for both carbonization and activation. The optimum operating temperatures for carbonization and activation were $650^{\circ}C$ and $900^{\circ}C$, respectively. For the activated carbons produced under these conditions, the iodine number was 1,127mg/g. Especially, removal efficiency of COD was 61.5% for 40mg/L of wastewater and 30% for 150mg/L of SLS(Sodium Lauryl Sulfate).