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Decomposition of CCl_4 and CHCl_3 on gliding arc plasma

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Journal of Environmental Sciences 2006年第1期18卷 83-89页

作者： Antonius Indarto choi Jae-wook LEE Hwaung SONG Hyung-keun Korea Institute of Science and Technology Clean Technology Research Center P.O. Box 131 Cheongryang Seoul 130-650 Korea Korea Institute of Science and Technology Clean Technology Research Center P.O. Box 131 Cheongryang Seoul 130-650 Korea.

Decomposition of chlorinated hydrocarbons, CCl4 and CHCl3, in gliding plasma was examined. The effects of initial concentrations, total gas flow rates, and power consumption have been investigated. The conversion result was relatively high. It reached 80% for CCl4 and 97% for CHCl3. Using atmospheric air as the carrier gas, the plasma reaction occurred at exothermic reaction and the main products were CO2, CO, and Cl2. Transformation into CCl4 was also detected for CHCl3 decomposition reaction. The conversion of CCh and CHCl3 were increased with the increasing applied frequency and decreasing total gas flow rate.

关键词： plasma gliding arc CCl4 CHCl3 decomposition reaction

A review of C_1 chemistry synthesis using yttrium-stabilized zirconia catalyst

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Journal of Rare Earths 2008年第1期26卷 1-6页

作者： Antonius Indarto Jae-wook choi Hwaung Lee Hyung Keun Song Plasma-Catalyst Chemical Process

C1 chemistry based on synthesis gas, methane, and carbon dioxide offers many routes to industrial chemicals. The reactions related to the synthesis of gas can be classified into direct and indirect approach for making such products, such as acetic acid, dimethyl ether, and alcohol. Catalytic syngas processing is currently done at high temperatures and pressures, conditions that could be unfavorable for the life of the catalyst. Another issue of C1 chemistry is related to the methane-initiated process. It has been known that direct methane conversions are still suffering from low yields and selectivity of products resulting in unprofitable ways to produce products, such as higher hydrocarbons, methanol, and so on. However, many experts and researchers are still trying to find the best method to overcome these barriers, for example, by finding the best catalyst to reduce the high-energy barrier of the reactions and conduct only selective catalyst-surface reactions. The appli- cation of Yttria-Stabilized Zirconia （YSZ） and its combination with other metals for catalyzing purposes are increasing. The existence of an interesting site that acts as oxygen store could be the main reason for it. Moreover, formation of intermediate species on the surface of YSZ also contributes significantly in increasing the production of some specific products. Understanding the phenomena happening inside could be necessary. In this article, the use of YSZ for some C1 chemistry reactions was discussed and reviewed.

关键词： C1 chemistry methane synthesis gas methanol yttria-stabilized zirconia catalyst oxygen storage rare earths

Quantitative comparison of similarity measure and entropy for fuzzy sets

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Journal of Central South University 2011年第6期18卷 2045-2049页

作者： JUNG Dong-yean choi Jung-wook PARK wook-Je LEE Sang-Hyuk Daeho Tech Changwon Gyeongnam Institute for Information and Electronics Research Inha University Department of Electrical and Electronic Engineering Xi'an Jiaotong-Liverpool University

Comparison and data analysis with the similarity measures and entropy for fuzzy sets were carried out. The distance proportional value between the fuzzy set and the corresponding crisp set was considered by the fuzzy entropy. The relation between the similarity measure and the entropy for fuzzy set was also analyzed. The fuzzy entropy was reformulated as the dissimilarity measure. Furthermore, crisp set having the minimum uncertainty with respect to the corresponding fuzzy set was also proposed. Finally, derivation of a similarity measure from entropy with the help of total information property was derived. A simple example shows the relation between similarity measure and fuzzy entropy, in which the summation of similarity measure and fuzzy entropy represents a constant value.

关键词： similarity measure fuzzy entropy minimum uncertainty quantitative comparison

Forecasting promising technology using analysis of patent information:Focused on next generation mobile communications

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Journal of Central South University 2014年第11期21卷 4303-4310页

作者： choi Seung-wook YOU Yen-Yoo NA Kwan-Sik Department of Knowledge Service & Consulting Hansung UniversitySeoul Korea Department of Management Information Systems Seowon UniversityCheongju Korea

In order to forecast promising technologies in the field of next generation mobile communication, various patent indicators were analyzed such as citation per patent, patent family information, patent share, increase rate, and patent activity. These indicators were quantified into several indexes and then integrated into an evaluation score to provide promising technologies. As a result of the suggested patent analysis, four technologies out of twenty two in details classification were selected, which showed outstanding technology competitiveness, high patent share and increasing rates as well as high recent-patent-ratios and triad-patent-family-ratios. Each of the selected technologies scored more than 10 points in total, and the following four technologies were suggested as promising ones in the field of next generation mobile communication: 1) 3GPP based mobile communication, 2) beyond 4G mobile communication, 3) IEEE 802.16 based mobile communication, which are in medium classification of broadband mobile communication system, and 4) testing/certification system of mobile communication, which is in medium classification of mobile communication testing/certification system.

关键词： next generation mobile communication promising technology forecasting patent information patent analysis patent indicators

Methane Conversion Using Dielectric Barrier Discharge: Comparison with Thermal Process and Catalyst Effects

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Journal of Natural Gas Chemistry 2006年第2期15卷 87-92页

作者： Antonius Indarto Jae-wook choi Hwaung Lee Hyung Keun Song Korea Institute of Science and Technology Clean Technology Research CenterP.O. Box 131CheongryangSeoul 130-650Korea

The direct conversion of methane using a dielectric barrier discharge has been experimentally studied. Experiments with different values of flow rates and discharge voltages have been performed to investigate the effects on the conversion and reaction products both qualitatively and quantitatively. Experimental results indicate that the maximum conversion of methane has been 80% at an input flow rate of 5 ml/min and a discharge voltage of 4 kV. Experimental results also show that the optimum condition has occurred at a high discharge voltage and higher input flow rate. In terms of product distribution, a higher flow rate or shorter residence time can increase the selectivity for higher hydrocarbons. No hydrocarbon product was detected using the thermal method, except hydrogen and carbon. Increasing selectivity for ethane was found when Pt and Ru catalysts presented in the plasma reaction. Hydrogenation of acetylene in the catalyst surface could have been the reason for this phenomenon as the selectivity for acetylene in the products was decreasing.

关键词： plasma dielectric barrier discharge thermal process methane conversion catalyst

Partial Oxidation of Methane with Sol-Gel Fe/Hf/YSZ Catalyst in Dielectric Barrier Discharge: Catalyst Activation by Plasma

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Journal of Rare Earths 2006年第5期24卷 513-518页

作者： Antonius Indarto Jae-wook choi Hwaung Lee Hyung Keun Song Jelliarko Palgunadi Clean Technology Research Center Korea Institute of Science and Technology KoreaDepartment of Chemical and Biological Engineering Korea University Korea Clean Technology Research Center Korea Institute of Science and Technology Korea Hydrogen Energy Research Center Korea Institute of Science and Technology Korea

A 1% Fe-30% Hf over yttria-stabilized zirconia catalyst in combination with novel plasma-assisted activation techniques for a direct partial oxidation of methane to methanol was tested using dielectric barrier discharge plasma at ambient temperature and atmospheric pressure. However, instead of methanol, the reaction products were dominated by HE, CO, CO2, C2, and H2O. A catalytically activated plasma process increased the production of methanol compared with a noncatalytic plasma process. The maximum selectivity of methanol production was achieved using a catalyst that was treated at higher applied power.

关键词： methane oxidation dielectric barrier discharge catalyst plasma activation rare earths

The kinetic studies of direct methane oxidation to methanol in the plasma process

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Chinese Science Bulletin 2008年第18期53卷 2783-2792页

作者： INDARTO Antonius choi Jae-wook LEE Hwaung SONG Hyung Keun Department of Chemical and Biochemical Engineering Korea UniversitySeoul 136-701KoreaClean Technology Research Center Korea Institute of Science and Technology Seoul 130-650 Korea Clean Technology Research Center Korea Institute of Science and TechnologySeoul 130-650 Korea Clean Technology Research Center Korea Institute of Science and TechnologySeoul 130-650Korea

The research outlined here includes a study of methanol production from direct methane conversion by means of thermal and plasma method. The kinetic study, derived from thermal-based approach, was carried out to investigate thoroughly the possible intermediate species likely to be presented in the process. A set of plasma experiments was undertaken by using dielectric barrier discharge (DBD), classified as non-thermal plasma, done at atmospheric pressure and room temperature. Plasma proc- ess yields more methanol than thermal process at the same methane conversion rates and methane to oxygen feed ratios. Oxidation reaction of thermal process resulted CO and CO2 as the most dominant products and the selectivity reached 19% and 68%, respectively. Moreover, more CO and less CO2 were produced in plasma process than in thermal process. The selectivity of CO and CO2 by plasma was 47% and 20%, respectively. Ethane (C2H6) was detected as the only higher hydrocarbon with a signifi- cant concentration. The concentration of ethane reached 9% of the total products in plasma process and 17% in thermal process. The maximum selectivity of methanol, the target material of this research, was 12% obtained by plasma method and less than 5% by thermal process. In some certain points, the kinetic model closely matched with the experimental results.

关键词：等离子体热采方法部分氧化甲烷甲醇

Analysis of liver metastasis after resection for pancreatic ductal adenocarcinoma

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World Journal of Gastrointestinal Oncology 2012年第5期4卷 109-114页

作者： Kwang Yeol Paik Seong Ho choi Jin Seok Heo Dong wook choi Department of Surgery Yeouido St.Mary's HospitalCatholic UniversityCollege of Medicine# 62 Yeouido-dongYeongdeungpo-gu150-713 SeoulSouth Korea Department of Surgery Samsung Medical CenterSungkyunkwan University School of Medicine135-710 SeoulSouth Korea

AIM:To investigate the risk factors affecting the liver metastasis(LM) of pancreatic ductal adenocarcinoma(PDAC) after ***:We retrospectively analyzed 101 PDAC patients who underwent surgical resection at the Samsung Medical Center between January 2000 and December *** one patients with LM were analyzed for the time of metastasis,prognostic factors affecting LM,and ***:LM was found in 40.6%.The median time of the LM(n = 41) was 6.0 ± 4.6 mo and most LM occurred within 1 *** univariate analysis,tumor size,preoperative carbohydrate antigen 19-9,and perineural invasion were factors affecting LM after *** multivariate analysis,tumor size was the most important factor for *** univariate analysis,tumor cell differentiation was significant to LM in low-risk ***:LM after resection of PDAC occurs early and shows poor *** size is the key indicator for LM after resection.

关键词： Pancreatic ductal adenocarcinoma Liver metastasis Recurrence

Kinetic Modeling of Plasma Methane Conversion Using Gliding Arc

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Journal of Natural Gas Chemistry 2005年第1期14卷 13-21页

作者： Antonius Indarto Jae-wook choi Hwaung Lee Hyung Keun Song

Plasma methane (CH_4) conversion in gliding arc discharge was examined. Theresult data of experiments regarding the performance of gliding arc discharge were presented in thispaper. A simulation which is consisted some chemical kinetic mechanisms has been provided toanalyze and describe the plasma process. The effect of total gas flow rate and input frequencyrefers to power consumption have been studied to evaluate the performance of gliding arc plasmasystem and the reaction mechanism of decomposition. Experiment results indicated that the maximumconversion of CH_4 reached 50% at the total gas flow rate of 1 L/min. The plasma reaction wasoccurred at the atmospheric pressure and the main products were C (solid), hydrogen, and acetylene(C_2H_2). The plasma reaction of methane conversion was exothermic reaction which increased theproduct stream temperature around 30-50℃.

关键词： plasma gliding arc methane conversion reaction mechanism