• Journal of the Korean Statistical Society
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• 제34권3호
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• pp.197-208
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• 2005

We consider the problem for approximate solution of linear stochastic evolution equations driven by infinite-dimensional fractional Brownian motion with Hurst parameter $H\;\in$ (0,1/2). The error of the approximate solution for the explicit Euler scheme is investigated.

• Journal of Plant Biology
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• 제30권3호
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• pp.181-187
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• 1987

Copper inhibited PSII-mediated O2 evolution (H2OlongrightarrowDCIP, H2OlongrightarrowSiMo) but not PSImediated O2 uptake(DCIP. Asc.longrightarrowMV) in isolated Chinese cabbage chloroplasts. Copper toxicity on PSII-mediated O2 evolution was higher at alkaline condition than at acidic condition and was inhanced by light illumination after copper treatment. The increased toxicity by light illumination was not recovered by subsequent dark treatment. The inhibitory effect of copper on H2OlongrightarrowDCIP reaction was higher than that on H2OlongrightarrowSiMo reaction. This result suggests that there may be another inhibitory site of copper on PSII other than water oxidizing side of PSII.

• Journal of Microbiology and Biotechnology
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• 제21권5호
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• pp.519-524
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• 2011

The correlation between alcoholic fermentation rate, measured as carbon dioxide ($CO_2$) evolution, and the rate of hydrogen sulfide ($H_2S$) formation during wine production was investigated. Both rates and the resulting concentration peaks in fermentor headspace $H_2S$ were directly impacted by yeast assimilable nitrogenous compounds in the grape juice. A series of model fermentations was conducted in temperature-controlled and stirred fermentors using a complex model juice with defined concentrations of ammonium ions and/or amino acids. The fermentation rate was measured indirectly by noting the weight loss of the fermentor; $H_2S$ was quantitatively trapped in realtime using a pre-calibrated $H_2S$ detection tube which was inserted into a fermentor gas relief port. Evolution rates for $CO_2$ and $H_2S$ as well as the relative ratios between them were calculated. These fermentations confirmed that total sulfide formation was strongly yeast strain-dependent, and high concentrations of yeast assimilable nitrogen did not necessarily protect against elevated $H_2S$ formation. High initial concentrations of ammonium ions via addition of diammonium phosphate (DAP) caused a higher evolution of $H_2S$ when compared with a non-supplemented but nondeficient juice. It was observed that the excess availability of a certain yeast assimilable amino acid, arginine, could result in a more sustained $CO_2$ production rate throughout the wine fermentation. The contribution of yeast assimilable amino acids from conventional commercial yeast foods to lowering of the $H_2S$ formation was marginal.

• 세라미스트
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• 제22권2호
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• pp.182-188
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• 2019

Alternative energy sources to the systems using hydrocarbon fuels have been actively developed due to exhaustion of fossil fuels and issue of global warming by CO₂. Fuel cells have attracted great attentions to solve these issues as electricity can be produced with product of clean H₂O by using H₂-O₂ as a fuel. Besides, using reverse reactions make it possible to produce H₂ and O₂ gas from electrolysis of water. There are various fuel cells systems depending on the types of electrolyte, and in this mini-reviews, the main aim is to focus on perovskite oxides as a catalyst for oxygen-evolution reactions in alkaline electrolysis and its potential to application of alkaline electrolysis systems.

• 대한수학회논문집
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• 제15권4호
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• pp.605-616
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• 2000

We prove the non-homogeneous boundary value problem for population evolution equations is well-posed in Sobolev space H(sup)3/2,3/2($\Omega$). It provides a strictly mathematical basis for further research of population control problems.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2008년도 High Temperature Superconductivity Vol.XVIII
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• pp.89-89
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• 2008

• Journal of Ecology and Environment
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• 제34권4호
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• pp.401-410
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• 2011

We assayed the effects of simulated acid rain on the mass loss, $CO_2$ evolution, dehydrogenase activity, and microbial biomass-C of decomposing Sorbus alnifolia leaf litter at the microcosm. The dilute sulfuric acid solution composed the simulated acid rain, and the microcosm decomposition experiment was performed at 23$^{\circ}C$ and 40% humidity. During the early decomposition stage, decomposition rate of S. alnifolia leaf litter, and microbial biomass, $CO_2$ evolution and dehydrogenase activity were inhibited at a lower pH; however, during the late decomposition stage, these characteristics were not affected by pH level. The fungal component of the microbial community was conspicuous at lower pH levels and at the late decomposition stage. Conversely, the bacterial community was most evident during the initial decomposition phase and was especially dominant at higher pH levels. These changes in microbial community structure resulting from changes in microcosm acidity suggest that pH is an important aspect in the maintenance of the decomposition process. Litter decomposition exhibited a positive, linear relationship with both microbial respiration and microbial biomass. Fungal biomass exhibited a significant, positive relationship with $CO_2$ evolution from the decaying litter. Acid rain had a significant effect on microbial biomass and microbial community structure according to acid tolerance of each microbial species. Fungal biomass and decomposition activities were not only more important at a low pH than at a high pH but also fungal activity, such as $CO_2$ evolution, was closely related with litter decomposition rate.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.485-487
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• 2014

Nitrogen이 도핑된 graphene에서의 hydrogen evolution에 대한 촉매효과에 대해서 연구를 진행하였다. Reaction free energy를 계산하기 위해서 많은 N-doped graphene 모델을 계산하였으며 pH 조건, silicon cathode의 영향 그리고 zero point energy의 효과를 고려하였다. Volcano plot에 의하면 "pyrol" like model과 N-doped armchair graphene model (aGNR-N1)이 좋은 촉매효과를 가짐을 밝혔다. 또한 free energy diagram을 통하여 "pyrol"과 "aGNR-N1"이 좋은 active site가 될 수 있음을 확인하였고 pH가 증가함에 따라 $H^+$의 에너지가 증가함에 따라 촉매 효과가 줄어듬을 확인하였다.

• 천문학논총
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• 제30권2호
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• pp.331-333
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• 2015

Gravitational interactions - mergers and fly-by encounters - between galaxies play a key role as the drivers of their evolution. Here we perform a cosmological N-body simulation using the tree-particle-mesh code GOTPM, and attempt to separate out the effects of mergers and fly-bys between dark matter halos. Once close pair halos are identified by the halo finding algorithm PSB, they are classified into mergers ($E_{12}$ < 0) and fly-by encounters ($E_{12}$ > 0) based on the total energy ($E_{12}$) between two halos. The fly-by and merger fractions as functions of redshift, halo masses, and ambient environments are calculated and the result shows the following.(1) Among Milky-way sized halos ($0.33-2.0{\times}10^{12}h^{-1}M{\odot}$), $5.37{\pm}0.03%$ have experienced major fly-bys and $7.98{\pm}0.04%$ have undergone major mergers since z ~ 1; (2) Among dwarf halos ($0.1-0.33{\times}10^{12}h^{-1}M{\odot}$), $6.42{\pm}0.02%$ went through major fly-bys and $9.51{\pm}0.03%$ experienced major mergers since z ~ 1; (3) Milky-way sized halos in the cluster environment experienced fly-bys (mergers) 4-11(1.5-1.7) times more frequently than those in the field since z ~ 1; and (4) Approaching z = 0, the fly-by fraction decreases sharply with the merger fraction remaining constant, implying that the empirical pair/merger fractions (that decrease from z ~ 1) are in fact driven by the fly-bys, not by the mergers themselves.

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.179-185
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• 2001

Nitrate grown cells of cyanobacterium Plectonema boryanum, transferred to nitrogen stress, evolved nitrogenase catalyzed $H_2$ under microaerophilic condition. Nitrogen ($N_2$) in gs phase, low light intensity, and reducing substances in incubation phase stimulated $N_2$fixation ($H_2\;evolution$). Cyanobacterium grew slowly under microaerobic condition with a low intracellular ammonia pool. Nitrogen sources (${NO_3}^-,{NH_4}^+,\;and\;CH_3NH_3$) inhibited nitrogenase and glutamine synthetase (GS) transferase activity, and methylamine behaved like an ammonical nitrogen source. Depletion of molybdenum (Mo) and addition of tungsten (W) in the incubation medium inhibited $H_2$ evolution, Cyanobacterium was able to take up nitrate and expressed nitrate reductase (NR) activity under microaerophilic condition at an extremely slow rate.