• 분석과학
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• 제24권2호
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• pp.113-118
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• 2011

톨루엔에 녹인 부틸고무 용액을 탄소가루의 결합재로 사용하였을 때, 탄소반죽은 용매 증발 후 기계적 경도를 보였다. 고무 용액의 이런 성질을 이용하여 닭의 간조직이 혼입된 새로운 과산화수소 정량 효소전극을 제조하였다. 그것이 전기화학적으로 정량적 행동을 보이는지 확인하기 위하여 그것의 전기화학적 파라메타 즉 이중층의 대칭인자, 교환전류밀도, 축전용량, Michaelis 상수 및 시간상수 등을 도출하였다. 실험 결과는 부틸고무 용액이 탄소가루의 결합재로 활용될 수 있음을 보여 주었다.

• 환경위생공학
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• 제21권4호
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• pp.49-60
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• 2006

The ion exchange resins have been synthesized from chlormethyl styrene - 1,4 - divinylbenzene(DVB) with 1%, 2%, 4% and 8%-crosslinking and 1-aza-18-crown-6 macrocyclic ligand by copolymerization method. Content of chlorine in styrene-DVB copolymer was decreased as crosslink increased and it is because as crosslink increased 1%, 2%, 4% and 8% DVB content increased and crosslink density increased and cavity was reduced. Functional group of resin almost disappeared as C-C1 peak around $700cm^{-1}$ was substituted with 1-aza-18-C-6 macrocyclic ligand and new peak of C-N around $1020cm^{-1}$ appeared, so it was confirmed that styrene-DVB copolymer and ligand were compounded. As crosslink increased in the analysis of element contents, it resulted in the reduction of nitrogen content and it is because as crosslink increased, it led to the reduction of chlorine content in the process of substitution reaction and it affected macrocyclic ligand substituted. Thermo analysis curve of functional synthetic resin decomposed three part of 1-aza-18-C-6, styrene, and DVB. Form of functional synthetic resin showed distortion of its particles as macrocyclic ligand was introduced to styrene-DVB copolymer and hydrogen of ligand caused substitution with chlorine element of styrene molecule.

• 한국토양비료학회지
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• 제29권4호
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• pp.321-327
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• 1996

교환성 알루미늄과 수소이온에 의한 토양의 교환산노를 적정과정중 희석에의한 적정상의 오차를 최소화한 역 정정법을 검토하였다. 이 방법은 증류수에 의한 현탁액과 동일한 농도의 중성염 용액으로 처리한 후 1N HCl로 pH3으로 맞춘 다음 1N NaOH고 조정된 용액으로 적정하는 방법이다. 이 방법과 표준법과 비교한 결과 평형곡선과 잘 일치하여 사용 가능성이 입증되었다.

• Asian Journal of Atmospheric Environment
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• 제9권2호
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• pp.158-164
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• 2015

The estimation of the concentration of hydroxyl radical (OH) in the atmosphere is essential to build atmospheric models and to understand the mechanisms of the reactions involved in OH. Although water vapor is one of the most abundant species in the troposphere, only a few studies have been performed for the reaction of OH and water vapor. Here I demonstrate an ab initio study on the complex forming reation of OH with $H_2O$ in the gas phase performed based on density functional theory to calculate the reaction rate and the energy states of the reactant and the OH-$H_2O$ complex. The structure of the complex, which belongs to the Cs point group, was optimized at global minima. The transition state was not found at the B3LYP and MP2 levels of theory. Rate constants of the forward and the reverse reactions were calculated as $1.1{\times}10^{-16}cm^3\;molecule^{-1}\;s^{-1}$ and $5.3{\times}10^9\;s^{-1}$, respectively. The extremely slow rates of complex forming reaction and the resulting hydrogen atom exchange reaction of OH and $H_2O$, which are consistent with experimentally determined values, imply a negligible possibility of a change in OH reactivity through the title reaction.

• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.271-275
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• 1999

The intracellular superoxide dismutase (SOD) from Staphylococcus sciuri was isolated to homogeneity by continuous steps, including ammonium sulfate fractionation, DEAE-ion-exchange chromatography, gel filtration, and phenyl hydrophobic gel chromatography. Pure SOD had a specific activity of 4,625 U/mg and was purified 158-fold with a yield of 31 % from a cell free extract. The molecular weight of the purified SOD was determined to be approximately 35.5 kDa by gel filtration and the enzyme was also shown to be composed of dimeric subunits on denaturing SDS-PAGE. The enzyme activity remained stable at pH 5 to 11 and also to heat treatment of up to $50^{\circ}C$ at pH 7.8, with 80% relative activity. The enzyme was insensitive to cyanide, hydrogen peroxide, and azide, indicating that it is a manganese-containing SOD. The EPR spectrum showed the enzyme containing manganese as a cofactor.

• 분석과학
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• 제11권3호
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• pp.174-178
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• 1998

Formaldehyde와 resorcinol을 반응시켜 chelating 수지를 제조하였다. 이 수지는 Pb(II)나 Ni(II)와 같은 전이금속에 대해 높은 흡착능을 나타내었다. Pb(II), Ni(II), Co(II), Fe(II)와 Zn(II)의 흡착과 탈착율을 batch법으로 구하였다. 이 수지의 중요한 특성은 금속 이온과 수지의 수소 이온간의 교환과정이다. 금속이온의 흡착과 탈착의 메카니즘은 수지의 작용기인 수소 이온의 탈착과 금속 이온간의 교환반응으로 생각된다. 이 수지를 이용하여 전이금속을 농축시키고, 다른 이온들로부터 Pb(II)를 분리하는데 적용해 보았다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.317-317
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• 2011

Enhanced ICRF (Ion Cyclotron Range of Frequency) ion heating of H-mode D(H) plasma will be tried in 2011 KSTAR experimental campaign. Minority heating is a main ion heating scheme in the ICRF. Its efficiency increases as the hydrogen minority ratio increases in deuterium plasmas. And it should be sustained at a lower level than the critical minority ratio. Consequently, it is important to elevate the critical ratio to maximize ion heating and it is possible by increasing the ion temperature or parallel wave number (k${\parallel}$) of the antenna. Increasing the k${\parallel}$ is not a good approach since the coupling efficiency decreases exponentially with regard to k${\parallel}$ as well. So the remaining method is to increase ion temperature by using NB (Neutral Beam). Ion heating fraction of NB increases as the electron temperature increases. Therefore, we will try to heat electron by using ECH together with NB ion heating before ICRF power injection. The ICRF heating efficiency will be compared with respect to several NB+ECH+ICRF heating combinations through several diagnostics such as XICS (Xray Imaging Crystal Spectroscopy), CES (Charge Exchange Spectroscopy) and neutron measurement. The theoretical background and the experimental results will be presented in more detail in the conference.

• Carbon letters
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• 제7권1호
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• pp.1-8
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• 2006

The activated carbon "C" was obtained by carbonization followed by activation with steam at 40% of burn-off. Oxidized carbons C-N, C-P and C-H were obtained by oxidizing the activated carbon C with concentrated nitric acid, ammonium peroxysulfate and hydrogen peroxide, respectively. The textural properties of the carbons were determined from nitrogen adsorption at 77 K. The acidic surface functional groups were determined by pH titration, base neutralization capacity and electrophoretic mobility measurements. The cation exchange capacities of un-oxidized and oxidized carbons were determined by the removal of Cu(II) and Ni(II) from their aqueous solutions. The surface area and the total pore volume decreased but the pore radius increased by the treatment of activated carbon with oxidizing agents. These changes were more pronounced in case of oxidation with $HNO_3$. The surface pH of un-oxidized carbon was basic whereas those of the oxidized derivative were acidic. The removal of Cu(II) and Ni(II) was pH dependent and the maximum removal of the both ions was obtained at pH of 5-6. Cu(II) was more adsorbed, a phenomenon which was ascribed to its particular electronic configuration.

• 천문학회보
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• 제41권1호
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• pp.50.2-50.2
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• 2016

Continuous accretion of metal-poor gas can explain the discrepancy between the number of observed G-dwarfs and the number predicted by the "simple model" of galactic evolution. The maximum accretion rate estimated based upon approaching high velocity clouds (HVCs) can be up to ${\sim}0.4M_{\odot}{\cdot}yr^{-1}$ which is comparable with the accretion rate required by many chemical evolution models that is at least ${\sim}0.45M_{\odot}{\cdot}yr^{-1}$. However, it is not clear to what extent the exchange of gas between the disk and the cloud can occur when an HVC collides with the galactic disk. Therefore, we examined a series of HVC-Disk collision simulations using the FLASH 2.5 hydrodynamics simulation code. The outcomes of our simulations show that an HVC will more likely take away substances from the galactic disk rather than adding new material to the disk. We define this as an HVC having a "negative fuel rate". Further results in our study also indicate that the process and amount of fuel rate change can have various forms depending on the density, radius and velocity of an approaching HVC. The simulations in our study covers HVCs with a neutral hydrogen volume density from $1.0{\times}10^{-2}cm^{-3}$ to $41.0cm^{-3}$, radius of 200 pc to 1000 pc and velocity in the range between $40km{\cdot}s^{-1}$ and $100km{\cdot}s^{-1}$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.93-94
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• 2006

In this research, the enhancement of electron-transfer activity of hemoglobin (Hb) in dodecanoic acid film was investigated for the first time. This type of composite film was made on glassy carbon electrode by casting method. Cyclic voltammetric result of the modified electrode displays a well defined redox peaks which was attributed to the direct electrochemical response of Rb. Our results illustrate that Rb exchange electrons directly with electrode and exhibits the characteristics of peroxidase. When we apply this modified electrode as a biosensor, it gives excellent performances in the electrocatalytic reduction of hydrogen peroxide ($H_{2}O_{2}$). Through the optimal conditions, the proposed biosensor shows the linear range for H2O2 determination was from $1{\times}10^{-5}$ to $1.25{\times}10^{-4}mol/L$ with a detection limit of $1{\times}10^{-7}mol/L$. The biosensor retained more than 90% of the initial response after 14 days.