• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.733-736
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• 2000

Lignin is usable as fuels and heavy oil additives if depolymerized to monomer unit, because the chemical structures are similar to high octane materials found in gasoline. In this study, the solvent-phase thermal cracking(solvolysis) of lignin was performed at the various temperature and time in a laboratory tubular reactor. Conversion yield was measured for the properties of thermal cracking and liquefaction reaction of lignin. Highest conversion yield when acetone was used as thermal cracking solvent was 55.5% at $350^{\circ}C$, 50minutes and highest tar generation were $260{\sim}350mg/g\;{\cdot}\;lignin$ at $250^{\circ}C$, and highest conversion yield after tar removal was 76.88% at $300^{\circ}C$, 30minutes. Conversion yield, product compositions and amounts were determined by tar degradation yield.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.560-565
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• 2005

Catalytic performances of zeolite catalysts such as H-mordenite(HM), H-Beta$(H{\beta})$, H-USY(HUSY) for the transmethylation between 1-methylnaphthalene(1-MN) and 2-methylnaphthalene(2-MN) were investigated in a fixed-bed flow reactor. $H{\beta}$ showed higher and more stable conversion than others to exhibit a high and stable 2-MN/1-MN ratio of 2.3 and 2,6-DMN/2,7-DMN ratio of 1.3 at the $1^{st}$ hour of time on stream under the reaction conditions as follows: reaction temperature of $350^{\circ}C$, reaction pressure of 1.5 MPa, WHSV of $2.7g_{feed}/g_{cat}{\cdot}h$ and the molar ratio of 1-MN and 2-MN of 1:1. The catalytic behavior has been discussed in relation with the catalyst pore structure and acidity.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.574-582
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• 2009

$UO_2$ microsphere particles, core material of HTGR(High Temperature Gas Reactor) nuclear fuel, were prepared using by the GSP(Gel Supported Precipitation) method which is a modified-method of the wet sol-gel process. The spherical shape of initial liquid ADU droplets from the vibration nozzle system was continuously kept till the conversion to the final $UO_2$ microsphere. But the size of a final $UO_2$ microsphere was shrunken to about 25% of an initial ADU droplet size. Also, we found that the composition of dried-ADU gel particles was constituted of the very complicated phases, coexisted the U=O, C-H, N-H, N-O, and O-H functional groups by FT-IR. The important factors for obtain the no-crack $UO_2$ microsphere during the thermal treatment processes must perfectly wash out the remained-$NH_4NO_3$ within the ADU gel particle in washing process and the selections of an appropriate heating rate at a suitable gas atmosphere, during the calcining of ADU gel particles, the reducing of $UO_3$ particles, and the sintering of $UO_2$ particles, respectively.

• Journal of the Korean Society of Safety
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• v.24 no.3
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• pp.54-58
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• 2009

A substitute energy development has been required due to the exhaust of the fossil fuel and an environmental problem. Consequently, possible technologies producing hydrogen from water that does not release carbon is a very promising technology. Also, Iodine-Sulfur(IS) thermochemical water decomposition is one of the promising processes that are used to produce hydrogen efficiently using the high temperature gas-cooled reactor(HTGR) as an energy source that is possible to supply heat over 900$^{\circ}C$. In this study, to make a initiating events identification for the IS process, Master Logic Diagram(MLD) is used and 9 initiating events that cause a leakage of the chemical material are identified. Also, 6 events are identified among 9 initiating events above and are quantified using event tree.

• Journal of Electrochemical Science and Technology
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• v.7 no.2
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• pp.146-152
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• 2016

A combined system with PEMFC and reformer is introduced and optimized for the real use of this kind of system in the future. The hydrogen source to operate the PEMFC system is methanol, which needs two parts of methanol reforming reaction and preferential oxidation (PROX) for the hydrogen fuel process in the combined operation PEMFC system. With the optimized methanol steam reforming condition, we tested PROX reactions in various operation temperature from 170 to 270 ℃ to investigate CO concentration data in the reformed gases. Using these different CO concentration, PEMFC performances are achieved at the combined system. Pt/C and Ru promoted Pt/C were catalysts were used for the anode to compare the stability in CO contained gases. The alloy catalyst of PtRu/C shows higher performance and better resistance to CO than the Pt/C at even high CO amount of 200 ppm, indicating a promotion not only to the activity but also to the CO tolerance. Furthermore, in a system point of view, there is a fluctuation in the PEMFC operation due to the unstable fuel supply. Therefore, we also modified the methanol reforming by a scaled up reactor and pressurization to produce steady operation of PEMFC. The optimized system with the methanol reformer and PEMFC shows a stable performance for a long time, which is providing a valuable data for the PEMFC commercialization.

• Korean journal of food and cookery science
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• v.23 no.2 s.98
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• pp.221-226
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• 2007

This study was carried out to investigate the optimun conditions for the isolation of low molecular weight peptides containing histidine, and to evaluate the antioxidant effects of skipjack boiled extracts(SBE). The results are summarized as follows : L-histidine contents of the ordinary muscle and dark muscle extracts were $ 83.1{\pm}1.75{\mu}M/g\;and\;11.0{\pm}2.39\;{\mu}M/g$, respectively. The L-histidine level of the dark muscle was much lower than that of ordinary muscle in the SBE. The extracts were treated with alcalase and neutrase under different pH levels, temperatures, and times. The optimum hydrolysis conditions of SBE were pH 7.0 and a $60^{\circ}$C temperature for 2 hr in the batch reactor, which hydrolyzed 63% of the SBE. HPLC analysis showed a removing effect of the ultrafiltration permeate (UFP) to high molecular weight impurities in SBE. SBE and pure carnosine participated as inhibiting agents to, which was confirmed through the autoxidation processing of linoleic acid. UFP treatment improved the inhibiting ability of SBE to the autoxidation of linoleic acid. The reducing power of the UFP-treated ordinary muscle extracts were 10-fold higher than the dark muscle extracts, and 0.7-fold higher than 20 mM pure carnosine. The UFP-treated ordinary muscle extracts had greater reducing power activity than pure carnosine. The scavenging activities on DPPH radical of the different treated-SBE and pure carnosine were also investigated. Scavenging activities of the ordinary and dark muscle extracts and the pure carnosine were 90%, 70%, and 45%, respectively. In summary, Skipjack boiled extracts (SBE) demonstrated that low molecular weight peptides containing histidine are capable of inhibiting lipid oxidation. They also possessed effective abilities as free radical scavengers and reducing agents, and these activities may increase with increasing concentrations.

• Journal of environmental and Sanitary engineering
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• v.23 no.3
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• pp.9-22
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• 2008

This study was conducted to develop a system that processes harmful gases and dust, which being generated in the production of micro-inorganic fabric. This can be obtained by melt spinning raw materials such as agalmatolite, fluorspar, limestone, silica under high temperature at $1500-1600^{\circ}C$ in a glass recuperator using a dry method by Cyclone Reactor or Envelope Type (ET) type Bag Filter. If the number of the members of Korea Glass Industry Association reaches up to 45, the damage of the harmful gas being generated in recuperator should not be small. In addition, research of existing facilities showed the most of harmful gas treatment facilities which adopt wet treatment or semi-dry treatment process. This was caused the problems for wastewater and the second pollutive materials. Moreover, in the dust collecting facility behind recuperator, it is also problematic that electric dust collector requires enormous initial investment. We have researched various methods to show both economic and efficient new processes for the preventive facilities of recuperator. As the result of the experiments, the removal efficiencies of HF and SOx were 99% and 87%, respectively. Although it was insignificant reaction, a pretty much interesting result that NOx showed an absorption reaction with $Ca(OH)_2$(removal efficiency was more than 25%) was obtained.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.244-249
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• 2016

Anaerobic digester supernatant including high concentrations of nitrogen is recycled to water treatment line and make pollutant load increase in municipal wastewater treatment plant(MWTP). To treat nitrogen in anaerobic digester supernatant is suggested the method of MWTP retrofit. In this study, the lab scale reactor was operated about 200 days using supernatant of anaerobic digester. The results could draw operation condition that ammonium nitrogen removal efficiency more than 90% and nitrite conversion efficiency over 70%. Correlation between operation efficiency and operation factors was analyzed based on the operation results. Ammonium nitrogen remove efficiency and nitrite conversion efficiency were related to solid retention time (SRT), ammonium nitrogen load and ammonium nitrogen loading per unit mixed liquer suspended solid (MLSS). Results of this study can be used effective data on nitritation of supernatant of anaerobic digester, and be expected to increase availability of nitritation.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.2
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• pp.199-207
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• 2015

Solid materials of ammonia sources with SCR have been considered for the application of lean NOx reduction in automobile industry, to overcome complex problems of liquid urea based SCR. These solid materials produce ammonia gas directly with proper heating and can be packaged by compact size, because of high volumetric ammonia density. Among ammonium salts and metal ammine chlorides, calcium ammine chloride was focused on this paper due to low decomposition temperature. In order to make calcium ammine chloride in lab-scale, simple reactor and glove box was designed and built with ammonium gas tank, regulator, and sensors. Basic test conditions of charging ammonia gas to anhydrous calcium chloride are chosen from equilibrium vapor pressure by Van't Hoff plot based on thermodynamic properties of materials. Synthetic method of calcium ammine chloride were studied for different durations, temperatures, and pressures with proper ammonia gas charged, as a respect of ammonia gas adsorption rate(%) from simple weight calculations which were confirmed by IC. Also, lab-made calcium ammine chloride were analyzed by TGA and DSC to clarify decomposition step in the equations of chemical reaction. To understand material characteristics for lab-made calcium ammine chloride, DA, XRD and FT-IR analysis were performed with published data of literature. From analytical results, water content in lab-made calcium ammine chloride can be discovered and new test procedures of water removal were proposed.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.183-189
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• 1999

Zinc-based sorbents for $H_2S$ removal were prepared. The reactivity of sorbents was investigated by the successive cycles of sulfidation-regeneration at $650^{\circ}C$ in a fixed bed reactor. The desulfurization sorbents were prepared with granulation method to produce a spherical pellet with good attrition resistance. The fresh and reacted sorbents were characterized by X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS) and the characteristics of sorbents on calcination conditons were analysed by Mercury Porosimetery and BET. The reactivity of sorbents decreased as the number of sulfidation-regeneration cycle increased. It is due to the zinc loss and the increase of the diffusion resistance by sintering, cracking and spalling of sorbents at the high temperature.