• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.177-185
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• 2009

The failure analysis of scales deposited on automotive thermostat housing has been carried out. Observations using energy dispersive spectroscopy and electron probe micro analyzer indicate that the main components of scales are some of additives of coolant used. For a detailed investigation of organic matters pyrolysis-GC/MS is employed. The result shows that the main organic component is benzoic acid and furthermore, a small amount of acetophenone, benzene and phenyl group is detected. Based on the results of failure analysis performed, the scales on automotive thermostat housing appear due to the deposition of coolant components, followed by crevice corrosion, into gap between housing and rubber horse. New accelerated test methodology, which could mimic the scale formation and the crevice corrosion on thermostat housing, is developed considering the above results. In order to reproduce the real operating conditions, the accelerating factors, i.e. temperature and humidity, are changed and programmed. The reproducibility of the accelerated test proposed is confirmed after analyzing the scales obtained from the accelerated test.

• The Korean Journal of Mycology
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• v.16 no.3
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• pp.121-127
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• 1988

For selective purification of protein in Pleurotus cornucopiae (Per.) Rolland, affinity chromatography was performed by benzoyl-AH-Sepharose 4B gel synthesized using AH-Sepharose 4B with starting materials. Ligand capacity of benzoyl group was 9.3 micromole per milliliter of gel. Total apparent molecular weight of affinity protein was 255KD, which were protein complex of 29.5, 31.5 34.0, 71.0 and 89.0KD, respectively. The contents of nonpolar, polar, positively charged, and negatively charged amino acid were 45.68%, 26.93%, 11.81% and 15.58%, respectively. The nonpolar protein was selectively purified by hydrophobic ligand of benzoyl group of gel.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.351-357
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• 2003

Transuranic elements such as Pu, Am and Cm in synthetic solution of spent nuclear fuel samples were determined by electrodeposition followed by alpha-spectrometry after separation using anion exchange and extraction chromatography in order to determine the transuranic elements in radwaste samples from nuclear power plants. Plutonium was separated by 12M HC1-0.1M HI as an eluent on anion exchange column. As a second step Am and Cm were separated in a group by DTPA-Lactic acid as the eluent on HDEHP coated column. The nuclides of $^{239}Pu$, $^{241}Am$및 $^{244}Cm$ separated were determined by alpha-spectrometry after electrodeposition in 0.1M $NaHSo_4$-0.53M $Na_2SO_4$buffer solution as an electrolyte. The recovery yields of $^{239}Pu$, $^{241}Am$및 $^{244}Cm$ were 83.8%, 85.2% and 86.3%, respectively, from the synthetic solution containing uranium and non-radioactive metal elements.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.664-668
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• 2016

The contamination in soil, underground water and river environment became serious due to illegal waste dumping. In this study, our research group analyzed the oil species of illegally disposed oils from J City. After pretreating the mixture of oil, water and solid phases to obtain homogeneous phase components, the physical property analysis, atom analysis, and gas chromatography were performed. From the results showing 11.8% of oxygen content, $-6^{\circ}C$ of pour point and chromatogram pattern. the contaminated oil was identified as a vegetable one. High performance liquid chromatography (HPLC) analysis was also performed in order to know what kind of vegetable oil was, and the ratio of LLO, OOL and POL was found to be high indicating that the disposed oil is majorly the used soybean oil with some vegetable oil mixtures. This study can be used for identifying contaminators for oils from the illegal waste dumping.

• Analytical Science and Technology
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• v.6 no.1
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• pp.121-129
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• 1993

UV/VIS spectrophotometer interfaced with HPIC(High Performance Ion Chromatography) has been applied to the determination of lanthanide elements. The separation of lanthanide elements with HPIC helped to avoid erroneous analytical results due to interferences. Individual lanthanide elements at ppm level were separated on a HPIC CS5 column using pyromellitic acid and oxalic acid. The individual lanthanide elements were detected at 520nm following post-column reaction with PAR. Sm, Eu, Gd, Y, Tb, Dy, Ho, Er, Tm, Tb, and Lu were separated by pyromellitic acid. La, Ce, Pr and Nd were separated by oxalic acid. Appropriate pH of pyromellitic acid for separation was at pH 2.99.

• Journal of Bio-Environment Control
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• v.10 no.2
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• pp.106-110
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• 2001

In an effort to evaluate the economic value and durability of the expanded rice hull as substrates, changes in the physical and chemical properties of material and plant growth in that substrate were studied. Using and electron microscope, the structure of used and new expanded rice hull substrate was examined. Considerable decomposition was found in the substrate which had been used one to three times. Compactness and lowered porosity in the used substrates were probably caused by decomposition. The results of cation analysis showed the possible destruction of cell wall of rice hulls. Abundant $Ca^{2+}$ in the substrates used for two to three times also indicated the possibility of decomposition. In tomato yield comparison, 15.2% more yield of tomato fruit in a new substrates indicated the negative effects of decomposition of one-time used substrates. Yield decreased in the substrates used for three times. if perlite substrates is used for three years before renewal and the cost of the perlite renewal is counted. 65.3% saving in the cost will be realized with the use of an expanded rice hull substrate. Another positive effect of the expanded rice hull substrate is the decrease of environmental contamination.n.

• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.750-756
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• 1996

$TiO_2$ was dispersed in zeolite and glass filter by soaking them in isopropanol solution of titanium tetraisopropoxide and drying in the air, followed by calcination at $500^{\circ}C$. The analysis of chlorothalnoil was carried out by gas chromatograph with an electron capture detector. Chlorothalnoil was degraded photocatalytically over the matrix-supported $TiO_2$ efficiently and could be completely photodegraded after 3hrs. Production were 5.0ppm of $Cl^-$ for $TiO_2$ supported zeolite, 7.5ppm of $Cl^-$ for $TiO_2$ supported glass filter and 2.0ppm of $Cl^-$ for $TiO_2$ powder. But, $CN^-$ was lower than the detection limit irrespective of matrices.

• Journal of Life Science
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• v.21 no.11
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• pp.1631-1635
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• 2011

The capability of synthesizing polyphenol glycosides was examined using recombinant amylosucrase from the hyperthermophilic bacterium Deinococcus geothermalis. Based on the action mode of amylosucrase, sucrose and twenty-one polyphenols were used as a donor and acceptors respectively. The transglycosylation reaction by amylosucrase produced one or two major polyphenol glycosides depending on the type of polyphenols used. The synthesized polyphenol glycosides were detected by thin-layer chromatography. The structures of the newly synthesized polyphenol glycosides were predicted based on the transglycosylation mechanism of the enzyme. According to the acceptability of the polyphenols, the structural characteristics of polyphenol as an efficient acceptor were evaluated. The results indicate that amylosucrase is an efficient catalyst for the enzymatic synthesis of polyphenol glycosides, which have high potentials in food, cosmetics, and pharmaceutical industries.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.322-328
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• 1999

Volatile flavor components of watermelon (Citrullus vulgaris S.) and oriental melon (Cucumis melo L.) obtained by simultaneous steam distillation and extraction apparatus were separated by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). Thirty seven and fifty five volatile flavor components were identified in watermelon and oriental melon, respectively. (Z)-3-Nonen-1-ol, (Z,Z)-3,6-nonadien-1-ol, (E,Z)-2,6-nonadienal and (E)-2-nonenal containing unsaturated nine carbon atoms were the characteristic flavor components of watermelon. $C_{9}-Unsaturated$ esters including (Z)-3-nonenyl acetate, (Z)-6-nonenyl acetate, (Z,Z)-3,6-nonadienyl acetate and thioester were important components in the flavor profile of oriental melon.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.99-106
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• 2017

In this study, mixed catalytic char gasification of Indonesia low-rank coal Kideco was investigated under nitrogen atmosphere and isothermal conditions at a fixed reactor. The effects of the temperature were investigated at various temperature (700, 750, 800, $850^{\circ}C$). The effects of blend ratio of catalysts ($K_2CO_3$, Ni) were investigated with different blend ratios (1:9, 3:7, 5:5, 7:3 and 9:1). The sample was prepared by mixing with $K_2CO_3$ physically and by ionexchange method with Ni. The data from thermogravimetric analyzer and gas chromatography were applied to four gassolid reaction kinetic models including shrinking core model, volumetric reaction model, random pore model and modified volumetric reaction model.