• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.3
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• pp.213-218
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• 1987

The DNA damage mechanism by fish oil peroxidation was investigated through the model system of a DNA-mackerel lipid at $37^{\circ}C$. Mackerel lipid peroxidation products induced a great DNA damage with the increment of its concentration, and such DNA damage in all systems examined occurred below $100millieq{\cdot}/kg$ in POV (peroxide value) Singlet oxygen $(^1O_2)$ and superoxide anion${\cdot}O_2^-$ greatly participated in the DNA damage during peroxidation of mackerel lipid, while hydrogen peroxide$(H_2O_2)$ and hydroxyl radical $({\cdot}OH)$ did little show the DNA damage. From the results of the addition of several active oxygen scavengers to the DNA-lipid systems, singlet oxygen ana superoxide anion greatly affected to the increase of POV ana to the DNA damage by mackerel lipid peroxidation, respectively. It indicates that there was a close relationship between the effects of active oxygens in the mackerel lipid peroxidation and its DNA damage mechanism.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.137-137
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• 2011

급격한 세계인구의 증가에 의해 물 부족지역이 세계 각지로 확산되고 있다. 이에 따라, 건전한 수자원으로써 하수처리수의 재이용이 주목을 받고 있다. 하수처리수의 재이용시에는 특히, 재이용수의 미생물학적 안전성과 더불어 화학물질 등으로부터 기인할 수 있는 인체 및 생태계에의 리스크를 고려해야 한다. 미국 EPA는 병원성 미생물 뿐만 아니라 화학물질에 대한 안전성을 확보 차원에자외선/과산화수소 등의 고도산화처리법을 검토하였다. 1일 $10m^3$ 처리규모의 연속실험장치를 이용, 검토된 공정별 실제 하수 2차 처리수중에 존재하는 의약품류의 제거효과, 에너지 소비량 및 생태리스크 저감효과 등을 비교, 평가하였다. 에너지 소비량에 있어서는 공정별로 다소 차이가 있었으나, 본 실험동안 검출된 38종의 의약품류 제거에는 각 공정 모두 매우 효과적이었다. 에너지 소비측면에서는 오존 단독공정이 가장 적은 에너지 소비량에서 타 공정과 동일한 수준의 의약품류 서 막처리나 자외선 처리 등의 고도처리시설에 대한 정보를 재이용수 가이드라인에 제시하고 있는 반면, 우리나라에서는 재이용수중에 일정농도 이상의 염소가 잔류하도록 함으로써, 재이용수의 미생물학적 안전성 확보만을 고려하고 있다. 최근, 수환경분야에서는 의약품류라는 화학물질이 유럽, 미국 및 일본 등지를 중심으로 주목을 받아오고 있으며, 이들은 ng/L-${\mu}g$/L 수준으로 수환경중에서 검출되고 있다. 이들의 주요 발생원으로 하수처리시설이 지목되고 있으며, 따라서 하수처리수의 재이용시 잔류 의약품류에 의한 리스크 발생 가능성이 우려되고 있다. 이를 배경으로, 하수처리시설에서 의약품류를 효과적으로 제거할 수 있는 공정으로 오존 및 오존/자외선, 제거효과가 얻어졌다. 한편, 오존처리시 발암성 물질인 브로메이트($BrO_3^-$) 등과 같은 부생성물 생성 가능성을 고려하면, 오존 단독공정보다 상대적으로 많은 에너지를 소비하는 오존/자외선, 자외선/과산화수소 등의 고도산화처리법이 높은 적용성을 갖는 것으로 나타났다. 향후, 수자원 부족문제로 재이용수의 용도가 훨씬 다양해 질 것으로 예상된다. 그에 따라, 재이용수의 안전성 확보를 위해 보다 폭넓은 검토가 예상되지만, 현 단계에서는 오존을 포함, 다소 많은 에너지 소비가 예상되는 자외선을 이용한 고도산화처리법이 다양한 미량 화학물질의 제거에 유효한 공정으로 판단된다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.4
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• pp.300-307
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• 1987

The present study was investigated on the DNA damage by the peroxidation of polar and non-polar lipid fractionated from mackerel lipid to elucidate the DNA damage mechanism by fish oil peroxidation. The degree of DNA damage by polar lipid peroxidation became greater with the increase of its concentration, and such DNA damage was induced below 100 millieq./kg in POV for 4 days incubation. Among the polar lipid peroxidation products, singlet oxygen $^1O_2$ and superoxide anion ${\cdot}O_2^-$ greatly affected to the DNA damage than hydrogen peroxide $H_2O_2$ and hydroxyl radical ${\cdot}OH$. Non-polar lipid peroxidation also induced the DNA damage with the increase of its concentration, but such effect was lower than the case of total lipid and polar lipid. And, the effects of active crygens on the DNA damage by non-polar lipid peroxidation was the same as in the case of total and polar lipid peroxidation.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.365-372
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• 1993

$CO_2$ methanation was performed over Ni supported on cation-exchanged Y zeolites under atmospheric pressure at $250{\sim}550^{\circ}C$ and $H_2/CO_2$ mole ratio of 4. Adsorption strength between carbon dioxide and nickel was found to be Influenced by the cation exchanged in the zeolite. TPD(Temperature-programmed desorption) results show that the adsorption strength decreases in the order of Ni/NaY>Ni/MaY>Ni/HY. TPSR(Temperature-programmed surface reaction) results indicate that enhanced methanation activity is obtained when the adsorption strength between carbon dioxide and nickel is stroing. As the reduction temperature increases, the methantion activity of the catalyst increase. From this result the larger size nickel particle seems advantageous for $CO_2$ methanation reaction. The maximum activity is obtained when nickel loading is 3.3wt%. Carbon monoxide is produced as a by-product throughout the reaction temperature range, and as the contact time increases, the selectivity to methane increases and the selectivity to carbon monoxide decreases steadily. Thus methane seems to be produced from $CO_2$ via CO as an intermediate species. In the temperature range of $410{\sim}450^{\circ}C$, the methane production rate is found to be dependent on the orders of 3.3~-0.5 and 1.4~3.6 with respect to $CO_2$ and $H_2$ partial pressures, respectively. This clearly shows that $CO_2$ and $H_2$ are competing for adsorption sites and as the reaction temperature increases, it becomes increasingly difficult for $H_2$ to be adsorbed on the catalyst surface.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.321-326
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• 2006

Thermal degradation of styrene dimer fraction (SDF, main compound: 47 wt% of 1,3-diphenylpropane), 5~15% of total products produced during decomposition of waste expanded polystyrene (WEPS) was investigated. Reaction condition of $360^{\circ}C$, and 152 kPa to 202 kPa was an optimum for high pressure degradation. Under this operating condition, the yield of oil was 73.8% and the selectivities to Ben, Tol, EB, SM, and AMS were 0.4, 30.9, 15.0, 19.6, and 4.2%, respectively. Non-catalytic fixed bed continuous degradation was conducted at reaction temperatures of $510{\sim}610^{\circ}C$ and contact time ranges of 2~24 min, where the yield was increased by increasing of reaction temperature and contact time. A $Cr_2O_3$ catalyst showed the highest activity and SM yield among acid, base, and redox catalysts. The conversion of 74.6% and the yield of Ben, Tol, EB, SM, and AMS were 0.4, 21.6, 9.7, 17.9, and 3.5%, respectively at $560^{\circ}C$ and contact time of 24 min. It is thought that styrene is converted to EB and other secondary products throughout the formation of diradicals of styrene.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.920-926
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• 1997

The catalytic glycolysis process is the method of chemical recycling where the polyol and carbamate compounds recovered by transesterification reaction are reused to produce new polyurethane foams. In this work, ethylene glycol, diethylene glycol, and 1,4-butanediol were used to decompose polyurethane foams and various metallic acetates were provided as catalysts. The catalytic glycolsis of polyurethane foams was taken place in the reaction temperature of $180{\sim}200^{\circ}C$. The reaction rates of catalytic glycolysis reaction were indicated by the viscosity of the reaction products at different reaction times. IR and GPC analysis showed the types and the molecular weight distributions of the products. The catalytic glycolysis was profitable for using ethyleneglycol at high temperature. The activities of the catalysts are suitable for K, Na, Tl acetate, and the products are composed of comparatively high-contained amine compounds and carbamate compounds. In the case of Sr acetate and Quinoline, the reaction rate was somewhat low. However, the content of polyol was high and the content of the side-products was low. The foams which were prepared by blending up to 20wt% of recovered polyol with virgin polyols showed better physical properties in tensile strength, hardness, tear strength, and compressive strength compared to those of polyurethane foams from virgin polyol.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.334-340
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• 2011

Squid was fermented with fermentation accelerators to develop a natural complex seasoning. The quality properties of fermented squid were determined at different fermentation periods. Squid fermented with 10% Aspergillus oryzae koji for 10 days had the highest amino-N, acidity, and total viable cell content during fermentation periods, whereas volatile basic nitrogen content and pH were the lowest. Based on the amino-N content, squid with 10% koji fermented for 10 days was selected for further analyses. The inosine and glutamic acid contents of the fermented squid were highest innucleotide composition, their related compounds, and free amino acids, respectively. The $IC_{50}$ values of the fermented squid on DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging and ${\alpha}$-glucosidase inhibitory activities were 6.20 and 4.41 mg/mL, respectively. Based on the results of a sensory evaluation, the fermented squid seasoning was similar to other natural complex seasonings such as anchovy, cowmeat, and fisheries seasonings.

• Clean Technology
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• v.18 no.3
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• pp.325-328
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• 2012

The condensation reaction of 9,9'-bis(4-hydroxyphenyl)fluorene with epichlorohydrin to prepare 9,9'-bis[4(glycidyloxy) phenyl]fluorene (2), an important building block for fluorene-containing epoxy polymers, has been studied. The reaction is found to be quite sensitive to several experimental conditions such as reaction temperature and time, added amount of epichlorohydrin, the presence of catalysts and the use of co-solvent. Several conditions for obtaining the best yield in the reaction are: the reaction temperature is below 373 K and the reaction time is shorter than 1.5 h, and the ammonium salts act as a catalyst. Also, the use of ternary solvent (toluene, DMSO, water) has been proved to be crucial to maintain the reaction temperature and for an easy purification. Thus, the reaction proceeds in an environment-friendly manner where the use of reactants and the production of chemical wastes is minimized.

• Clean Technology
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• v.19 no.4
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• pp.416-422
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• 2013

In environmental friendly aspects, the synthesis of glycerol carbonate from glycerol using carbon monoxide and oxygen gases which were produced in petrochemical plants was studied. The oxidative carbonylation of glycerol under batch reaction system was performed on parameter conditions such as effect of various metals (Cu, Pd, Fe, Sn, Zn, Cr), oxidizing agents, mole ratio of carbon monoxide to oxygen, catalyst amount, solvent types, reaction temperature and time and dehydrating agents. In particular copper chloride catalysts showed the excellent activities, and the glycerol carbonate yields over CuCl and $CuCl_2$ catalysts were the maximum of 44% and 64%, respectively at the following reaction conditions: solvent as nitrobenzene, mole ratio of 1:3:0.15 (glycerol:carbon monoxide:catalyst), mole ratio of 2:1 (carbon monoxide:oxygen), the total pressure of 30 bar at 413 K for 4 hr. It was found that reactivity were significantly different depending on the oxidation number of Cu catalysts, and oxygen plays an important role as oxidizing agents in producing H2O during oxidation reaction after carbonylation of glycerol.

• Journal of Radiation Protection and Research
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• v.28 no.2
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• pp.109-116
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• 2003

Based on the necessity to evaluate the activation products inventory during decommissioning lot domestic nuclear power plants, a preliminary estimation of the activation products inventory for Kori unit 1, which is getting close to the end of lifetime, was carried out with ANISN and ORIGEN2 code. In order to calculate neutron nux using ANISN code, the reactor was divided into 9 zones from core to bioshield concrete for radial direction. Also :he cross-section of main nuclides were calibrated with neutron flux in the reactor pressure vessel(RPV) region. The results showed that 95 % of tile total radioactivity in RPV from reactor shutdown to 10 years came from the nuclides of $^{55}Fe,\;^{59}Ni,\;^{63}Ni\;and\;^{60}Co$. And the total radioactivity with cooling of more than 50 years after decommissioning was no more than 0.2 % of at the time of shutdown. Considering the weight of RPV is 210 tons, the total radioactivity of RPV reached to $5.25{\times}10^{6}GBq$ at shutdown time. As compared with the total radioactivity of bioshield concrete at reactor shutdown time, the radioactivity after tooling more than 10 years was below 1 %.