• 한국자동차공학회논문집
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• 제14권3호
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• pp.125-132
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• 2006

Transient kinetics of $NH_3$ adsorption/desorption and of SCR(selective catalytic reduction) of NO with $NH_3$ were studied over vanadium based catalysts, such as $V_2O_5/TiO_2$ and $V_2O_5-WO_3/TiO_2$. In the present catalytic reaction process, NO adsorption is neglected while $NH_3$ is strongly chemisorbed on the catalytic surface. Accordingly, it is ruled out the possibility of a reaction between strongly adsorbed $NH_3$ and NO species in line with the hypothesis of an Eley-Rideal mechanism. The present kinetic model assumes; (1) non-activated $NH_3$ adsorption, (2) Temkin-type $NH_3$ coverage dependence of the desorption energy, (3) non-linear dependence of the SCR reaction rate on the $NH_3$ surface coverage. Thus, the surface heterogeneity for adsorption/desorption of $NH_3$ is taken into account in this model. The present study extends the pure chemical kinetic model based on a powdered-phase catalytic system to the chemico-physical one applicable to a realistic monolith reactor.

• 한국수소및신에너지학회논문집
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• 제22권5호
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• pp.714-720
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• 2011

Ethanol was used as reducing agent to remove $NO_x$ exhaust from the stationary source. Pre-treatment with sulfuric acid over $Ag/Al_2O_3$ catalyst was dedicated to overcome the $SO_2$ poisoning effect. The $NO_x$ reduction experiment was performed under the simulated condition of power plant The increased surface area with higher CPSI devoted to increase de-$NO_x$ yield. De-$NO_x$ yield of the $NO_x$ exhaust containing 20 ppm of $SO_2$ increased after acid treatment with 0.7% $H_2SO_4$ over 4.0% $Ag/Al_2O_3$, where the increased dispersion of Ag found from the results of XRD and XPS was the dominant factor for the increased de-$NO_x$ yield. However, the reason for the decreased de-$NO_x$ yield with the acid treatment of higher concentration (1.0% and 2.0%) of $H_2SO_4$ was found to be due to the formation of $Ag_2SO_4$ crystallites found from XRD result. Acid-treated $Ag/Al_2O_3$ catalyst showed maximum de-$NO_x$ yield at higher temperature than non-treated $Ag/Al_2O_3$ catalyst did.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.598-606
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• 2001

A mathematical model is proposed that can depict the kinetics of simultaneous saccharification and fermentation (SSF) using steam-exploded wood(SEW) with a glucose- and cellobiose-fermenting yeast strain. Brettanomyces custersii. An expression to describe the reduction of the relative digestibility during the hydrolysis of the SEW is introduced in the hydrolysis model. The fermentation model also takes two new factors into account, that is, the effects of the inhibitory compounds present in the SEW hydrolysates on the microorganism and the fermenting ability of Brettanomyces custersii, which can use both glucose and cellobiose as carbon sources. The model equations were used to simulate the hydrolysis of the SEW, the fermentation of the SEW hydrolysates, and a batch SSF, and the results were compared with the experimental data. The model was found to be capable of representing ethanol production over a range of substrate concentrations. Accordingly, the limiting factors in ethanol production by SSF under the high concentration of the SEW were identified as the effect of inhibitory compounds present in the SEW, the enzyme deactivation, and a limitation in the digestibility based on the physical condition of the substrate.

• 한국세라믹학회지
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• 제53권3호
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• pp.306-311
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• 2016

Li-air batteries have received much attention due to their superior theoretical energy density. However, their sluggish kinetics on the cathode side is considered the main barrier to high performance. The rational design of electrode catalysts with high activity is therefore an important challenge. To solve this issue, we performed density functional theory (DFT) calculations to analyze the adsorption behavior of the $LiO_2$ molecule, which is considered to be a key intermediate in both the Li-oxygen reduction reaction (ORR) and the evolution reaction (OER). Specifically, to use the activity descriptor approach, the $LiO_2$ adsorption energy, which has previously been demonstrated to be a reliable descriptor of the cathode reaction in Li-air batteries, was calculated on $LaB_{1-x}B^{\prime}_xO_3$(001) (B, B' = Mn, Fe, Co, and Ni, x = 0.0, 0.5). Our fast screening results showed that $LaMnO_3$, $LaMn_{0.5}Fe_{0.5}O_3$, or $LaFeO_3$ would be good candidate catalysts. We believe that our results will provide a way to more efficiently develop new cathode materials for Li-air batteries.

• 대한치과교정학회지
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• 제22권2호
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• pp.309-325
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• 1992

The purpose of this study was to evaluate the effect of intrinsic factor and extrinsic factor for growth of the mandibular condylar cartilage of 4 day-old rats in a serum-free medium for 1, 4, 7, 14 days. They were compared with normal growth in vivo and with growth of spheno-occipital synchondrosis in serum-free medium. The cellular kinetics of cartilages were evaluated by auto-radiography of tritiated thymidine. 1. Condylar cartilage was enlarged with rounded head on day 14 of experiment while in vivo the rounded-headed shape changed into functionally flattened appearance. 2. On day 14 of experiment, a severe reduction of the proliferative zone and a considerable increase of the hypertrophic zone were observed while in normal control group endochondrol bone formation and bone marrow were observed. 3. The proliferative activity in the proliferative zone of condylar cartilage detected by $^3H-thymidine$ incorporation was lower than that of normal control group and decreased more than that of spheno-occipital synchondrosis, but it continued during the 14 days of culture. 4. The continued maintenance of condylar cartilage and morphologic change were disturbed in this culture system, but cell division within the proliferative zone was continued and probably linked to intrinsic factor.

• BMB Reports
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• 제42권12호
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• pp.817-822
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• 2009

Type-1 phosphatase (PP-1) was assessed in foot muscle (FM) and hepatopancreas (HP) of estivating (EST) Otala lactea. Snail PP-1 displayed several conserved traits, including sensitivity to inhibitors, substrate affinity, and reduction in size to a 39 kDa catalytic subunit (PP-1c). During EST, PP-1 activity in FM and HP crude extracts was reduced, though kinetics and protein levels of purified PP-1c isoforms were not altered. PP-1c protein levels increased and decreased in nuclear and glycogen-associated fractions, respectively, during EST. Gel filtration determined that a 257 kDa low $K_m$ PP-1$\alpha$ complex decreased during estivation whereas a 76 kDa high $K_m$ complex increased in EST. Western blotting confirmed that the 76 kDa protein consisted of PP-1$\alpha$ and nuclear inhibitor of PP-1 (NIPP-1). A suppression of PP-1 activity factors in the overall metabolic rate depression in estivating snails and the mechanism is mediated through altered cellular localization and interaction with binding partners.

• 공업화학
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• 제26권5호
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• pp.624-629
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• 2015

호모게나이저로 파쇄한 쑥 조직을 탄소반죽에 혼입시켜 과산화수소 감응 바이오센서를 제작하고 그것의 전기화학적 특성을 전압전류법으로 살펴보았다. Hanes-Woolf 도시의 좋은 직선성은 기질분해가 쑥 과산화효소에 의하여 촉매화되고 있음을 보여 주었으며, 작은 값의 대칭인자(${\alpha}$, 0.28)는 전극전위의 변화가 반응속도변화에 미치는 영향이 대단히 민감한 것을 말하여 주었다. 이런 실험적 사실들은 과산화수소의 분해가 쑥전극 표면에 있는 과산화효소의 촉매력에 의하여 정성적, 정량적으로 분해되고 있음을 보여 주는 것으로 서양 고추냉이로부터 추출된 고가의 시판 과산화효소를 쑥 조직으로 대치할 수 있음을 확신하게 하는 것이다.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.817-820
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• 2010

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by extreme insulin deficiency due to an overall reduction in the mass of functional pancreatic ${\beta}$-cells. Several animal models have been used to study T1DM. Amongst these, the mini-pig seems to be the most ideal model for diabetes research, owing to similarities with humans in anatomy and physiology. The purpose of this study was to analyze differentially expressed pancreatic proteins in a streptozotocin (STZ)-induced mini-pig T1DM model. Pancreas proteins from mini-pigs treated with STZ were separated by two-dimensional gel electrophoresis, and 11 protein spots were found to be altered significantly when compared with control mini-pigs. The data in this study utilizing proteomic analysis provide a valuable resource for the further understanding of the T1DM pathomechanism.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.368-371
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• 2006

[ $La_{0.8}Sr_{0.2}Co_{1-x}Mn_xO_3$ ] cathode as a high performance cathode on YSZ electrolyte was studied by analyzing impedance spectra. It was shown that cathode property of $La_{0.8}Sr_{0.2}Co_{1-x}Mn_xO_3$ is bet ter than that of$La_{0.8}Sr_{0.2}CoO_3$. At $700^{\circ}C$ in air environment, $La_{0.8}Sr_{0.2}Co_{0.4}Mn_{0.6}O_3$ cathode on CGO- layered YSZ electrolyte showed very low area specific resistance of $0.14{\Omega}cm^2$, which is low enough for intermediate-temperature sol id oxide fuel cells. This is because material properties of ionic conductivity and thermal expansion compatibility with electrolyte were optimized. Judging from activation energy and oxygen part i al pressure dependance of cathode property, it was noted that oxygen surface exchange kinetics is dominantly influential on cathode property in higher temperature region than $700^{\circ}C$ and oxygen self-diffusion in cathode material is more influential in lower temperature region.

• Journal of Microbiology and Biotechnology
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• 제21권2호
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• pp.136-146
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• 2011

This study provides first-hand proteomic data on the survival strategy of Anabaena sp. PCC 7120 when subjected to long-term iron-starvation conditions. 2D-gel electrophoresis followed by MALDI-TOF/MS analysis of iron-deficient Anabaena revealed significant and reproducible alterations in ten proteins, of which six are associated with photosynthesis and respiration, three with the antioxidative defense system, and the last, hypothetical protein all1861, conceivably connected with iron homeostasis. Iron-starved Anabaena registered a reduction in growth, photosynthetic pigments, PSI, PSII, whole-chain electron transport, carbon and nitrogen fixation, and ATP and NADPH content. The kinetics of hypothetical protein all1861 expression, with no change in expression until day 3, maximum expression on the $7^{th}$ day, and a decline in expression from the $15^{th}$ day onward, coupled with in silico analysis, suggested its role in iron sequestration and homeostasis. Interestingly, the up-regulated FBP-aldolase, Mn/Fe-SOD, and all1861 all appear to assist the survival of Anabeana subjected to iron-starvation conditions. Furthermore, the $N_2$-fixation capabilities of the iron-starved Anabaena encourage us to recommend its application as a biofertilizer, particularly in iron-limited paddy soils.