• Journal of Korean Society of Environmental Engineers
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• v.37 no.8
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• pp.458-464
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• 2015

Total petroleum hydrocarbon (TPH) removal and temperature variations in bunker fuel oil C contaminated soil were investigated by using microwave radiation in the presence of triiron oxide or activated carbon as a heating element. Temperature increments of $1.4{\sim}1.6^{\circ}C/Watt$ were observed, when 100~500 watt of microwave radiation was applied for the contaminated soil in the presence of triiron oxide or activated carbon. Temperature variation of the soil was more rapid in the presence of triiron oxide than activated carbon. 10% or 25% of heating element content was required to reach the temperature of thermal desorption for triiron oxide and activated carbon respectively. After radiation, 44.1% and 89.4% of initial TPH in soil was removed in the presence of triiron oxide and activated carbon respectively. It was observed that activated carbon was more reactive than triiron oxide for the removal of high molecular carbon of bunker fuel oil C.

• Clean Technology
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• v.19 no.3
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• pp.279-286
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• 2013

Using a cation exchange resin of polystyrene-DVB copolymer as a carbon source for the production of activated carbon, the effects of operating parameters on the physical properties of activated carbon such as specific surface area and specific pore volume were experimentally studied. In carbonization process specific surface area and specific pore volume of carbonized product decreased with the increase of carbonization temperature and time. They were proportional to activation temperature and time up to the specific temperature and time in activation process. In carbonization process the increase of heating rate gave negative effect to the properties. The properties of activated product, on the contrary, increased with the heating rate in carbonization process. The properties of activated carbon manufactured with the resin exchanged with divalent cations were lower than those with raw resin.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7433-7438
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• 2015

Deactivation characteristics of $V_2O_5/TiO_2$ catalysts were studied for selective catalytic reduction(SCR) of NOx with ammonia in the presence of $SO_2$. Performance of catalyst was investigated for $deNO_x$ activity while changing temperature, $SO_2$ concentration. The activity of catalyst was decreased with the increase of $SO_2$ concentration and reaction time. Also, degree of activity drop was largely decreased with the increase of reaction temperature in the range of $250{\sim}300^{\circ}C$. Physicochemical properties of deactivated catalysts were characterized by BET, XRD, SEM, TPD analysis. According to the analysis results, deactivation phenomena occur due to the relatively high formation of ammonium sulfate salts, which created by unreacted ammonia and water in the presence of $SO_2$. It was revealed that ammonium sulfate cause the pore plogging of support and deposition of active matter.

• Journal of the Korean Chemical Society
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• v.43 no.6
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• pp.614-620
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• 1999

The critical micelle concentration (CMC) and the counterion binding constant (${\beta}$) at the CMC of the mixtures of Dodecylpyridinium chloride (DPC) and Tetradecyltrimethylammonium bromide (TTAB) have been determined from the concentration dependence of electrical conductance at various temperatures from $4^{\circ}C$ to $36^{\circ}C$. Thermodynamic parameters (${\Delta}C_p$, ${\Delta}G^o_m$, ${\Delta}H^o_m$ and ${\Delta}S^o_m$), associated with the micelle formation of DPC/TTAB mixtures, have been estimated from the temperature dependence of CMC and ${\beta}$values. The measured values of ${\Delta}C_p$ and ${\Delta}G^o_m$ are negative but the values of ${\Delta}S^o_m$ are positive in the whole measured temperature region. The values of ${\Delta}H^o_m$ are positive at low temperature region and negative at high temperature region. The results show that all of the thermodynamic parameters are dependent on temperature and mole fraction of DPC(${\alpha}_DPC$).

• Journal of the Korean Ceramic Society
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• v.37 no.9
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• pp.839-846
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• 2000

통전활성 소결법을 이용하여 단상의 세라믹스(PSZ) 및 금속(NiCrAlY)과 PSZ/NiCrAlY 복합체를 각 소결온도에서 제조하였으며, 이에 대한 특성평가는 개량형 소형펀치 시험법을 이용하여 수행하였다. 복합체의 밀도 및 경도에 미치는 소결온도의 영향은 NiCrAlY의 부피분율 증가에 따라 감소되었으며, 중간조성에서의 밀도 및 경도는 연속적인 변화를 나타내었다. 파괴인성의 변화에서는 60vol%-NiCrAlY 이상의 조성에서 급격한 증가를 나타내었으며, 짧은 소결시간 및 빠른 승온속도 등 통전활성 소결법의 장점에 의해 단상의 PSZ에서도 10 MPa.m$^{1}$2/ 의 높은 파괴인성 값을 얻을 수 있었다. PSZ/NiCrAlY 복합체에서의 특성은 소결온도와 NiCrAlY의 부피분율에 의해 지배적으로 영향을 받았으며, 단상의 PSZ은 전형적인 취성거동을 나타내었고 80vol%-NiCrAlY 까지의 복합체에서는 부분적인 취성 및 소성거동을 함께 나타내었다. 각 소결체에서 최고의 특성을 나타내고 소결온도는 단상의 PSZ 경우인 140$0^{\circ}C$에서부터 단상의 NiCrAlY 경우인 120$0^{\circ}C$까지 최대 20$0^{\circ}C$의 차이를 나타내었으며, PSZ과 NiCrAlY의 조성비에 따라서 연속적인 변화를 보였다.

• The Korean Journal of Zoology
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• v.30 no.2
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• pp.167-176
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• 1987

배추흰나비의 전용기 혈림프에서 $\beta$-N-Acetylglucosaminidase를 DEAE-cellulose ion exchange 및 Sephadex G-200 column chromatography 법을 이용하여 정제하였다. 정제된 효소는 7% acrylamide gel 전기영동에서 단일 band를 나타내었으며, 당을 함유한 복합단백질이었다. 최적 pH는 5.0, 최적반응온도는 6$0^{\circ}C$이었으며, 각 온도에서 10분간 incubation한 열안정성에 있어서는 6$0^{\circ}C$까지 비교적 높은 활성을 나타내었지만 7$0^{\circ}C$ 이후에는 거의 활성을 나타내지 않았다. 또한 Hg$^2$+ 처리는 심한 효소활성의 저해 현상을 보였지만, Mn$^2$+, $Mg^2$+ 등은 활성의 증가를 나타내었으며, Km 값은 6.67$\times$10-$^3$M, pl 값은 5.8, 분자량은 4.1$\times$105 daltons 이었다.

• Resources Recycling
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• v.12 no.3
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• pp.13-24
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• 2003

The production characteristics of activated carbon from waste walnut shell have been investigated by taking activation temperature, activation time, amount of activating agent, and kind of activating agent as the major influential factors. The adsorption capacity of the activated carbon which was produced using phosphoric acid as the activating agent increased with activation temperature and showed its greatest value at about $550^{\circ}C$. Yield for activated carbon was observed to decrease continuously as the activation temperature was raised. The optimal activation time for the highest adsorption capacity was found to be about 2 hr, and as the activation time increased the yield for activated carbon was showed to decrease continuously. The increase in the amount of activating agent resulted in the increase of the yield for activated carbon, however, excessive amount of activating agent deteriorated its adsorption capacity reversely. The variations of the microstructure of activated carbon observed by SEM with several influential factors, correlated very well with its changes in the adsorbability with the same factors and the kind of activating agent was found to play an important role in the determination of the adsorption capacity of activated carbon. To investigate the adsorption characteristics of the produced activated carbon, the adsorption reactions of $Cu^{2+}$ ion were examined using the produced activated carbon as the adsorbent. In general, the kinetics of the adsorption of $Cu^{2+}$ ion was observed to follow a 2nd-order reaction and the rate constant for adsorption reaction increased as the initial concentration of adsorbate was diminished. The equilibrium adsorption of $Cu^{2+}$ was explained well with Freundlich model and its adsorption reaction was found to be endothermic. The activation energy for adsorption was calculated to be 13.07 kcal/mol, which implied that the adsorption reaction was very irreversible, and several thermodynamic parameters of adsorption reaction were estimated using van't. Hoff equation and thermodynamic relationships.

• Journal of Aquaculture
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• v.21 no.1
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• pp.41-46
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• 2008

The purpose of the study was to suggest the optimal lipid enrichment conditions used digestive enzyme activity of rotifer changing due to water temperature and salinity. The high population growth appeared at the experiment temperature more than 28 degrees highly on the culture temperature(maximum 32 degrees, 1,453 individual/mL). The fecundity was low at high temperature, and the egg ratio was high at low temperature. Population growth of 10 and 15 ppt appeared in most highly, but the fecundity and the egg ratio were high most significantly appeared in natural seawater(32 psu). The digestive enzyme activity by the culture environment mainly showed high activity in natural seawater(amylase exclusion, 15 psu). However, the TAP activity by the water temperature showed highly at the more high temperature, but the amylase and the lipase appeared at low temperature. We carried out the lipid enrichment at 20 degrees and 26 degrees in a condition of the natural seawater. Total protein, the total essential amino acids differed not significantly. The methionine content that was essential amino acids, a total lipid content, unsaturated index of fatty acids, DHA and the DHA/EPA ratio were high significantly each in $20^{\circ}C$ enrichment trial. Therefore, we could suggest the $20^{\circ}C$ and natural seawater for the optimal lipid enrichment condition in aquaculture, because methionine contents, several indexes by the lipid, TG-lipase activity, fecundity and egg ratio are high.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.591-597
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• 2012

This study was conducted to investigate the changes in chemical components and antioxidant activities of dried jujube ($Zizyphus$ $jujuba$ Miller) with different aging temperatures ($60^{\circ}C$, $70^{\circ}C$, and $80^{\circ}C$) and durations (5 days, 10 days, 15 days, 30 days, and 50 days). The browning index increased from 0.124 to 1.998 with increased aging temperature and duration. As aging duration increased, fructose, glucose, and sucrose content decreased from 24.96% to 4.96%, from 22.23% to 4.41%, and from 18.41% to 0%, respectively. Reducing sugar content decreased from 351.52 mg/g to 155.96 mg/g as aging temperature and duration increased. Total acidity slightly increased from 1.61 to 3.13%. 5-Hydroxymethyl-2-furaldehyde increased from 0.002 mg/g to 38.84 mg/g, respectively. As aging temperature and duration increased, total polyphenol content increased from 15.98 mg/g to 38.61 mg/g. DPPH and ABTS radical scavenging activities increased from 4.03 mg trolox eq/g to 22.22 mg trolox eq/g, and from 2.11 mg ascorbic acid eq/g to 13.39 mg ascorbic acid eq/g, respectively. Reducing power increased rapidly in the first stage and then slowly increased afterward.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1599-1605
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• 2005

The object of this study is to develop the method for differentiating fresh meat from frozen meat by using the measurement of the mitochondrial malate dehydrogenase in the Korean native cattle. The principle of this experiment is based on the fact that the enzyme proteins associated with mitochondrial membrane could be released by freezing. The methods of differentiating fresh meat from thawed, frozen meat were studied by measurements of mitochondrial malate dehydrogenase activity of meat press juice. Fresh and frozen beef were stored at 4, -4, -18 and -77$^{\circ}C$ for 15-day storage period. A meat press machine using air pressure was manufactured especially for these experiments, and sufficient amount of drip (about 0.15 mL/g) from 1.5 g of beef sample was efficiently obtained under a pressure of 8 kg/$cm^{2}$ generated by the meat pressing machine. The mitochondrial malate dehydrogenase activities of frozen meat drip i년ices stored at -18 and -77$^{\circ}C$ were significantly higher than those of fresh and frozen meat samples at -4$^{\circ}C$ (p < 0.05) during 10-min reaction period. However, the enzyme activities of the frozen meat drip juices (-18 and -77$^{\circ}C$) disappeared after 5 minutes of the reaction, which was not observed from the fresh and -4$^{\circ}C$ frozen meats. The enzyme activity maintained until 12 minutes for the fresh and -4$^{\circ}C$ frozen meats. From these results, the mitochondrial malate dehydrogenase could be considered as an indicator to differentiate fresh beef from frozen one.