• Journal of Electrochemical Science and Technology
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• v.15 no.3
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• pp.345-352
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• 2024

The synthesis of Pt nanoparticles and catalytically active materials using the electrochemical top-down approach involves dispersing Pt electrodes in an electrolyte solution containing alkali metal cations and support material powder using an alternating pulsed current. Platinum is dispersed to form particles with a predominant crystallographic orientation of Pt(100) and a particle size of approximately 7.6±1.0 nm. The dispersed platinum particles have an insignificant content of PtO_x phase (0.25±0.03 wt.%). The average formation rate was 9.7±0.5 mg cm^-2 h^-1. The nature of the support (carbon material, metal oxide, carbon-metal oxide hybrid) had almost no effect on the formation rate of the Pt nanoparticles as well as their crystallographic properties. Depending on the nature of the support material, Pt-containing catalytic materials obtained by the electrochemical top-down approach showed good functional performance in fuel cell technologies (Pt/C), catalytic oxidation of CO (Pt/Al₂O₃) and electrochemical oxidation of methanol (Pt/TiO₂-C) and ethanol (Pt/SnO₂-C).

• YAKHAK HOEJI
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• v.30 no.5
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• pp.228-231
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• 1986

The effect of temperature and pH on the degrdation of minoxidil in the aqueous solution was investigated and the stability of pharmaceutical preparation for solution was also studied. The degradation of minoxidil in the aqueous solution was first order type reaction and the rate constant at $20^{\circ}C$ in pH 7.0 phosphate buffer solution was 9.464${\times]10^{-3} day^{-1}$ and calculated activation energy was 11.7 kcal/mol. The degradation of minoxidil was acid-base catalytic reaction and the most stable range of pH was about 5.0. The liquid pharmaceutical preparation was very stable in 3 months.

• Proceedings of the Korean Vacuum Society Conference
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• 2002.02a
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• pp.149-149
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• 2002

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.05a
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• pp.87-87
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• 1998

• Journal of the Korea Safety Management & Science
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• v.2 no.4
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• pp.187-195
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• 2000

Electrochemical promotion of the reaction rate was investigated for CO oxidation in a solid electrolyte catalytic reactor where a thin film of Pt was deposited on the yttria stabilized zirconia as an electrode as well as a catalyst. It was shown under open circuit condition that potential was a mixed potential of $O_2$exchange reaction and electrochemical reaction induced by CO. The effect of electrochemical modification on the CO oxidation rate was studied at various overpotentials and $P_{CO}$$P_{O2}$.

• Carbon letters
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• v.7 no.3
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• pp.161-165
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• 2006

Activated carbon fiber could be prepared at 973 K by catalytic activation using potassium hydroxide. Phenol resin fiber (Kynol) was impregnated with potassium hydroxide ethanol solution, carbonized and activated at 973 K, resulting in activated carbon fibers with different porosities. The potassium hydroxide accelerated the activation of the fiber catalytically to form narrow micropore preferentially in carbon dioxide atmosphere. The narrow micropore volume of 0.3~0.4 cc/g, total pore volume of 0.3~0.8 cc/g, mean pore width of 0.5~0.7 nm was obtained in the range of 20~50% burnoff.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.231-232
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• 2000

자동차 보급의 증가에 의한 심각한 대기오염으로 인하여 국내 제작차(휘발유 자동차)의 경우 1987년부터 자동차 배기가스 정화용 촉매 전환기의 장착을 의무화하였다(환경부, 1998). 자동차용 촉매로 많이 사용되는 귀금속은 백금(Pt), 팔라듐(Pd), 로듐(Rh)이며, 수요비율은 백금이 전체 수요의 39%, 팔라듐이 16%, 로듐이 96%로 자동차용으로 많은 귀금속이 사용되고 있음을 알 수 있다. (중략)

• Journal of Ginseng Research
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• v.10 no.2
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• pp.193-199
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• 1986

To investigate the stability of ginseng saponin, various physical and chemical treatments for red ginseng alcohol extract (70% ethyl alcohol) were carried out, and then the variations of ginseng saponin in extract were investigated by high performance liquid chromatography (HPLC) method. Irradiation of ${\gamma}$-ray, and ultraviolet ray, sonocatalysis by ultrasonicator, treatment of electronic range, catalytic ozonation did not or slightly affect degradation of ginseng saponins, but they were degraded by heat treatment.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.96.2-96.2
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• 2010

The surface morphology and structural properties of polycrystalline silicon (poly-Si) films made in-situ aluminum induced crystallization at various substrate temperature (300~600) was investigated. Silicon films were deposited by hot-wire chemical vapor deposition (HWCVD), as the catalytic or pyrolytic decomposition of precursor gases SiH4 occurs only on the surface of the heated wire. Aluminum films were deposited by DC magnetron sputtering at room temperature. continuous poly-Si films were achieved at low temperature. from cross-section TEM analyses, It was confirmed that poly-Si above $450^{\circ}C$ was successfully grown on and poly-Si films had (111) preferred orientation. As substrate temperature increases, Si(111)/Si(220) ratio was decreased. The electrical properties of poly-Si film were investigated by Hall effect measurement. Poly-Si film was p-type by Al and resistivity and hall effect mobility was affected by substrate temperature.

• Journal of the Korean Applied Science and Technology
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• v.17 no.1
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• pp.15-21
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• 2000

The catalytic hydroxylation of several cycloalkanes in dichloromethane have been investigated using In(Ⅲ)-, Tl(Ⅲ)-porphyrin complexes as a catalyst and NaClO, $NaClO_{2}$, $H_{2}O_{2}$ as a terminal oxidant. Porphyrins were TPP and ($F_{20}$)TPP (TPP = tetraphenylporphyrin) and substrates were cyclopentane, cyclohexane, cycloheptane and cyclooctane. The substrate conversion yield was discussed according to the substituent effect and hinderance effect of metalloporphyrin and the radius effect of non-redox metal ion. The conversion yield of cycloalkane followed the order of $ C_{5} $ < $ C_{6}$ < $ C_{7}$ = $ C_{8}$. In this experimental condition $NaClO_2$ was rather efficient terminal oxidant than NaClO and $H_{2}O_{2}$.