• Journal of Ginseng Research
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• v.14 no.3
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• pp.373-378
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• 1990

Free malonaldehyde was determined in nine kinds of ginseng polyacetylene-treated micro- some by HPLC analysis. Antioxidant activities of some phenolic compounds and ginseng saponin were also drtermined both by a new HVLC method and by THA method. A new HPLC system separaterl malonaldehyde at a retention time 5,6 min and showed a linear relationship between the peak are a and malonaldehyde concentration. Panaxnol showed the strongest activity among nine polyacetylenes and the addition of either chlorine or aletyl group reduced polyacetylene's own activity. Since C14-polyacetylenes such as panaxyne and panaxyne-epoxide had little or no antioxidant activities, S17-structure should be preserved to exert a radical-scvenging or trapping activity. The antioxidant activities of chlorogenic acid, ferulic acid and catechol were much weaker than those of C17-polyacetylenes. Ginseng saponin showed no antioxidant activity. Since TBA reactive substances and malonaldehyde contents were almost the same in peroxiedized microsome. TBA value seems a good indicator for lipid peroxidation in this particular Fe+3 ADP/NADPH system.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.80-83
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• 2007

In order to characterize the catalytically active sites on carbon black, acetylene chemisorption had been examined recently at 773 and 873 K by using a pulse technique. As the inject ion was repeated at 773 K, the adsorbed amount gradually decreased and eventually the adsorption did not occur any more. At 873 K a constant amount of $C_2H_2$ was consumed repeatedly after several injections. Good linear relationships were obtained between the methane decomposition rate at 1123 or 1173 K and the cumulative acetylene adsorption at 773 K or the constant acetylene consumption at 873 K. Reasonable models for the associative acetylene chemisorption at 773 K and the constant acetylene consumption at 873 K on the armchair face at the edges of graphene layers were proposed. The constant consumpt ion may be explained by the "$C_2H_2$-addition-hydrogen- abstract ion (CAHA)" mechanism.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.356-356
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• 2011

탄소나노튜브(CNT)는 기계적, 전기적, 열적성질이 매우 우수하여 다양한 응용이 기대되고 있다. CNT를 금속기판에 직접 합성시킬 경우 CNT와 금속기판의 계면에서 높은 전도성 및 물리적 접착 강도를 기대할 수 있어서, 전계방출(field emission) 소자 또는 방열(heat dissipation) 소자 등과 같은 CNT의 높은 전도성과 일차원적 구조를 이용하고자 하는 분야로의 응용가능성을 높일 수 있다. 본 연구에서는 CNT의 합성촉매로 주로 사용되고 있는 니켈을 주요 성분으로 함유하고 있는 Inconel, Hastelloy, Invar 등을 합성기판으로 선정하여, CNT의 합성 거동을 조사하였다. CNT 합성은 CVD방법을 이용하였으며, 아세틸렌가스를 원료가스로 이용하였다. 합성 전 기판의산화 전처리가 CNT합성 효율에 영향을 미치는 것을 확인하였으며, 이를 체계적으로 조사하기 위하여, 다양한 온도(425~725$^{\circ}C$) 구간에서 산화 전처리를 실시한 후 CNT의 합성 거동을 조사하였다. 산화과정에 의한 표면구조의 변화 및 표면에서 금속성분의 재배열이 CNT합성 효율 변화의 원인으로 사료되고 있으며, 이를 분석하기 위해서, AFM, XRD, EDS, SEM, TEM 등을 이용하였다. 본 연구결과는 향후 전자방출소자, X-ray source 및 방열소자 등의 응용에 유용할 것으로 기대된다.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.80-89
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• 2002

The flame structure and soot formation in Acetylene-Air nonpremixed jet flame are numerically analyzed. We employed two variable approach to investigate the soot formation and oxidation processes. The present soot reaction mechanism involves nucleation, surface growth, particle coagulation, and oxidation steps. The gas phase chemistry and the soot nucleation, surface growth reactions are coupled by assuming that the nucleation and soot mass growth has the certain relationship with the concentration of pyrene and acetylene. We also employed laminar flamelet model to calculate the thermo-chemical properties and the proper soot source terms from the information of detailed chemical kinetic model. The numerical and physical model used in this study successfully predict the essential features of the combustion processes and soot formation characteristics in the reaction flow field.

• YAKHAK HOEJI
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• v.32 no.2
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• pp.137-140
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• 1988

To investigate polyacetylene compounds isolated from petroleum ether extract of panax ginseng effect on the macromolecule synthesis, lympoid lukemia L1210 cell was incubated with them at 4, 8, 12,16 hours. Panaxydol, panaxynol and panaxytriol as cytotoxic substances inhibited the synthesis of macromolecule such as DNA, RNA and protein. Panaxydol which had the most potent cytotoxicity among these three compounds showed the strongest inhibitory effect on DNA, RNA and protein synthesis. For DNA and RNA synthesis, panaxynol and panaxytriol decreased the rate of inhibition with the incubation time but panaxydol had a strongest inhibitory effect at 16 hour incubation time. Protein synthesis was markedly inhibited by all these polyacetylene compounds. It was obserbed that there is a relationship between cytotoxicities of polyacetylene compounds and the inhibition of macromolecule synthesis.

• YAKHAK HOEJI
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• v.39 no.6
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• pp.681-688
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• 1995

An n-hexane extract of the roots of Aralia cordata Thunb. (Araliaceae) was found to show significant in vitro cytotoxic activity against P388D$_{1}$ lymphocytic leukemia cell in culture. Bioactivity-directed fractionation of this extract led to the isolation of four polyacetylenes, falcarindiol (1), dehydrofalcarindiol (2), falcarindiol-8-acetate (3) and dehydrofalcarindiol-8-acetate (4). Cytotoxicity of compounds 1 and 3 was found to be better than that of compounds 2 and 4 when these compounds were tested against eight in vitro tumor cell lines, namely, A549, HCT15, DLD1, MCF7, SKOV3, HL60, K562 and P388D$_{1}$. The fact that the cytotoxicity of compounds 1 and 3 against series of tumor cell lines was much stronger than that of compounds 2 and 4 suggested that the saturated carbon chain at the termial and the hydroxyl group at the C-3 are important for the activities. The requirement for the activity was further confirmed by synthesizing and assaying the acetate derivatives of compounds 1 and 2.

• Journal of the Korean Institute of Gas
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• v.8 no.1 s.22
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• pp.25-29
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• 2004

First, this study carried out the numerical simulation of NG cutting nozzle developed for applying of NG inferior to ethylen, acethylen, LPG used in the existing cutting process in the characteristic of fuel. Second, to judge application and cutting performance of NG cutting nozzle, the experiments for applying in the field are carried out on the base of the results of numerical simulation.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.6
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• pp.335-340
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• 2000

We report the results of a preliminary investigation on capacitive humidity sensors using iodine-doped polyphenylacetylene(PPA) thin films. PPA was prepared from phenylacetylene(PA), chemically doped with iodine, and characterized by DSC, $^1H$-NMR and FTIR spectra. The iodine-doped PPA sensors showed a sensitivity of 0.20pF/%RH, a linearity of 3.8%FS, a negligible hysteresis, and a low temperature coefficients of $0.043~0.067pF/^{\circ}C$ over a wide range of relative humidity. These results are expected to open up the possibility of iodine-doped PPA thin films as relative humidity sensors.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.332-334
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• 2012

This study investigates records about state systems which were installed to manage aids to navigation workings related to ship and navigation in Korea. It shows the transition process from signal-fire that was used for safe sailing in the three kingdom period to the oil lamp, acetylene gas light, electric light and the LED lamp have been used as a light source for the lighthouses since the modern age.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.188-189
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• 2015

본 연구에서는 저온에서 증착이 가능한PECVD법을 이용하여 아르곤 가스 및 아세틸렌 가스 비율에 따른 기계적 구조적 특성 확인을 확인 후 공정압력 변화 실험을 통하여 DLC코팅의 특성을 확인하였다. 기계적 특성을 확인하기 위하여 나노인덴터를 이용하여 경도 및 탄성률을 측정하였으며, ball-on disk를 이용하여 마찰계수를 확인하였다. 각 샘플들의 부식 저항 특성을 확인하기 위하여 $1mole\;H_2SO_4+2ppm\;HF$ 분위기의 전해질 내에서 동전위 분극시험을 통한 내식성 테스트를 하였으며, 구조적 특성은 라만분광법을 이용하여 박막내의 sp3와 sp2 bond의 비율 변화를 확인하였다.