• Applied Biological Chemistry
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• v.22 no.1
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• pp.24-27
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• 1979

A study was carried out about the effect of free fatty acids and lecithin on the thermal inactivation of horseradish peroxidase. In presence of lecithin peroxidase was inactivated very rapidly at $70^{\circ}C$ and pH 7.0, and showed also a rapid inactivation curve at $0^{\circ}C$ and pH 4.0. Linoleic acid was more effective in an $O_2-stream$ than in a $N_2-stream$, but oleic acid showed a similar tendency in the presence of $O_2-and\;N_2$ stream. From the results of the experiment we suggested that the opening of the heme crevis of peroxidase in the presence of lecithin and the produced lipidperoxide from linoleic acid may accelerate the thermal inactivation of horseradish peroxidase respectively.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.05a
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• pp.31-31
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• 1997

• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.11a
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• pp.28-30
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• 2004

Effect of dietary brown seaweed (Undaria pinnatifida) levels on the performance, nutrients utilization, and blood anti-oxidant system was studied in broiler chicks activated innate immune response. Brown seaweed 2.0 % diet improved performance of broiler chicks and resulted in enhanced feed efficiency due to the increased NB and decreased UAN excretion significantly (P<0.05). Dietary brown seaweed reduced SOD activity in erythrocyte cytosol and enhanced peroxidase activity in plasma significantly(P<0.05). Activation of innate immune response increased SOD activity and peroxide levels in blood. The results indicated that dietary brown seaweed affected SOD and peroxidase activity and the increased performance in birds fed brown seaweed 2.0 % diet related with decreased decomposition of body protein and the change of anti-oxidant systems in blood of broiler chicks during activation of innate immune response.

• Journal of Life Science
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• v.22 no.9
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• pp.1137-1144
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• 2012

Inflammation is a host defense mechanism that is activated in response to harmful substances or pathogens. However, an excessive inflammatory response is a problem in itself. Macrophages secrete inflammatory mediators such as nitric oxide (NO) or cytokines through various pathways such as the nuclear factor kappa B (NF-${\kappa}B$)-activated pathway after recognizing pathogen-like lipopolysaccharides (LPSs). In this study, anti-inflammatory effects of Eupatorium chinensis var. simplicifolium (EUC) extracts were investigated using LPS-stimulated RAW 264.7 macrophages. The EUC root extract significantly reduced NO production, inducible nitric oxide synthase (iNOS) expression, and cyclooxygenase-2 expression in a concentration-dependent manner. In addition, the EUC root extract reduced phosphorylation of mitogen-activated protein kinases and protein kinase B, which is upstream of NF-${\kappa}B$. The EUC root extract also reduced the degradation of inhibitory kappa B. These results indicate that EUC root extract exerts anti-inflammatory effects, which are mediated by inhibition of iNOS expression and the NF-${\kappa}B$ pathway.

• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.320-327
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• 1998

The chemical aspects of nitridated surface of sapphire(0001) have been studied by X-ray photoelectron spectroscopy. Nitridated layer was formed by remote plasma enhanced-ultrahigh vacuum deposition at a low temperature range. It was confirmed that this nitridated surface was mainly consists of AIN layer. The relative amounts of nitrogen reacted with AL on the sapphire surface and their surface morphology were investigated with X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) as a function of radio-frequency power, reaction temperature, and reaction time. The amounts of atomic nitrogen activated by plasma which was subsequently incorporated into sapphire were increased with RF power. But the amounts of nitrogen reacted with AI in sapphire was initially increased and then remained constant. However, the relative amounts of AIN were nearly constant with irrespective of nitridation temperature and time. Furthermore, a depth porfile of nitridated layer with XPS showed that the nitridated surface consisted of three layers with different stoichiometry.

• Clean Technology
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• v.23 no.3
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• pp.308-313
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• 2017

In this study, we investigated the electrocatalytic effects of the N and O co-doping of Graphite Felt (GF) electrode for the vanadium redox flow battery (VRFB) at the cathode and the anode reaction, respectively. The electrodes were prepared by chemical vapor deposition (CVD) with $NH_3-O_2$ at 773 K, and its effects were compared with an electrode prepared by an O doping treatment. The surface morphology and chemical composition of the electrodes were characterized by scanning electron microscopy (SEM) and photoelectron spectroscopy (XPS). The electrocatalytic properties of these electrodes were characterized in a VRFB single cell comparing the efficiencies and performance of the electrodes at the cathode, anode, and single cell level. The results exhibited about 2% higher voltage and energy efficiencies on the N-O-GF than the O-GF electrode. It was found that the N and O co-doping was particularly effective in the enhancement of the reduction-oxidation reaction at the anode.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.133-139
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• 2000

In this study, activated carbon was prepared from solid residue after lignin pyrolysis by using zinc chloride as an activation agent. The steam activation method was adopted to manufacture activated carbon from solid residue after lignin pyrolysis. The effect of process operation variables such as activation temperature, activation time and mass of activation agent added to char on the pore structure and specific surface area of the activated carbon was investigated. Activated carbon with high surface area and well-developed pore structure could be prepared, when solid residue after lignin pyrolysis was mixed with zinc chloride of 300 wt% and then the mixture was activated for 1 hour at $1000^{\circ}C$ in a stream of nitrogen.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.136-136
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• 2010

$Ge_2Sb_2Te_5$ (GST)는 광학 스토리지 및 PRAM(Phase-change Random Access Memory)에 적용 가능한 대표적인 상변화 물질이며 상변화 거동에 대한 다양한 연구가 진행되고 있다. 차세대 비휘발성 메모리로 각광을 받고 있는 PRAM의 경우 저전력 그러나 향후 고집적, 고성능 PRAM 소자구현을 위해서는 Reset 전류 감소를 통한 소비 전력 감소, 인접 셀간의 'cross talking'을 방지할 수 있는 열적 안정성 개선 등의 문제점들을 해결해야 한다. GST 물질의 전기적, 열적 특성을 조절하여 이러한 문제를 해결하기 위하여 GST 물질에 이종의 원소를 첨가하는 연구가 활발히 진행되고 있으며, 특히 질소 첨가에 의해 결정 성장 억제를 통한 결정화 온도 증가, 결정질의 저항 증가 등의 보고가 있었다. 본 연구에서는 질소를 첨가한 N-doped $Ge_2Sb_2Te_5$ (NGST) 박막의 상변화 거동을 규명하고 GST 박막과 비교하여 첨가된 질소의 영향을 분석하고자 한다. D.C Magnetron sputtering 방법으로 증착된 GST와 NGST 박막을 등온으로 유지하여 각 온도별로 열처리 시간 증가에 따른 비저항을 실시간으로 측정하여 GST와 NGST 박막의 상분율을 계산하고 Kissinger 모델을 이용하여 effective activation energy ($E_a$)를 구하였다. GST와 NGST 박막의 $E_a$는 각각 $2.08\;{\pm}\;0.11\;eV$와 $2.66\;{\pm}\;0.12\;eV$로 계산되었다. 따라서 첨가된 질소에 의해 NGST 박막의 결정화를 위하여 GST 박막의 경우보다 더 큰 활성화 에너지가 필요하다.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.3
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• pp.81-88
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• 2000

Composting of N-rich wastes such as food waste and wastewater sludges can be associated loss of with substantial gaseous N, which means loss of an essential plant nutrient but may also lead to environmental pollution. We investigated the behavior of nitrogenous materials during the first high-rate phase in composting of food waste. Air dried food waste was mixed with shredded waste paper or wood chip and reacted in a bench scale composting reactor. Samples were analyzed for pH, ammonia, oxidized nitrogen and organic nitrogen. The volatilized ammonia nitrogen was also analyzed using sulfuric acid as an absorbent solution. Initial progress of composting reaction greatly influenced the ammonification of organic nitrogen. A well-balanced composting reaction with an addition of active compost as an inoculum resulted in the promoted mineralization of organic nitrogen and volatilization of ammonia. The prolongation of initial low pH period delayed the production of ammonia. It was also found that nitrogen loss was highly dependent on the air flow supplied. With an increase in input air flow, the loss of nitrogen as an ammonia also increased, resulted in substantial reduction of ammonia content in compost. The conversion ratio of initial nitrogen into ammonia was in the range of 28 to 38% and about 77~94% of the ammonia produced was escaped as a gas. Material balance on the nitrogenous materials was demonstrated to provide an information of importance on the behavior of nitrogen in composting reaction.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.445-449
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• 2012

The activation process of the membrane-electrode assembly (MEA) is important for the mass production of the polymer electrolyte membrane fuel cell. The conventional activation process for the MEA requires excessive time and hydrogen gas and it might become the barrier for the commercialization of the fuel cell. The conventional activation process is based on hydrolysis of ion conducting membrane. In the study, we suggest the cyclic voltammetry (CV) technique as an on-line activation process and the CV activation process consists of two steps : 1) the humidification of the polymer electrolyte membrane and the electrode with 100% RH humidified nitrogen ($N_{2}$) gas, and 2) the removal step of the oxide layer on the surface of the Pt catalyst with CV cycling. The cycling reduces the activation time of the MEA by 2.5 h and use of hydrogen gas by 1/4.