• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.923-926
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• 2008

Currently more high flow and high performance concrete is used for construction of buildings in the world. However, when high flow and high performance concrete put high performance water reducing agent in quantity to improve flow, it has a negative effect on concrete structures since segregation arises from it though flow will be improved. There are naked-eye observation, coarse aggregate washing test, L Flow test for permeation among reinforcing rods and measurement of viscosity to judge concrete segregation resistance. However, it is difficult to apply them to practical affairs since they are very complicated and troublesome. Therefore, the study analyzed EIS dividing slump flow value into slump value, how to valuate concrete segregation resistance more easily, on the basis of the existing reference materials to propose EIS. As the results, in the event of high flow concrete, it is desirable that EIS value is prescribed to be less than 2.5 at the time of managing segregation. Also, at the time of prescribing EIS with performance, it is judged that it is desirable to manage segregation as less than 2.2 (Grade 1), 2.2$\sim$2.4 (Grade 2) and more than 2.6 (Grade 3).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.325-328
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• 2013

Recently, the national carrier of the next-generation growth engine of M2M (machine to Machine) is attracting attention. Therefore, its uses and utilization of the various disciplines is getting wider, and the increasing number of terminals to be used compared to the existing communication of the information that is sent in every object may have increased. Each data transfer from the bulk terminal to a mobile network, if the traffic situation reaches this limit does not facilitate the processing of M2M communication services, this situation can occur. This study measures the mobile networks will be used in M2M communications when it reaches the breaking point for the smooth processing of M2M services are presented. Things grows increasingly smaller the further development of M2M technology, the explosion in mobile communication network, the data traffic will reach the limitations of these methods will be used in determining the ranking of the M2M communication services should be treated as a priority, to beM2M services to mobile networks will help to facilitate.

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.5
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• pp.388-400
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• 2021

Power to gas (P2G) is one of the energy storage technologies that can increase the storage period and storage capacity compared to the existing battery type. One of P2G technology produces hydrogen by decomposing water from renewable energy (electricity) and the other produces CH4 by reacting hydrogen with CO2. This study is an experimental study to produce CH4 by reacting CO2 of biogas with hydrogen using a 40 wt% Ni-Mg-Al catalyst and a commercial catalyst. Catalyst characteristics were analyzed through H2-TPR, XRD, and XPS instruments of 40% Ni catalyst and commercial catalyst. The effect on the CO2 conversion rate and CH4 selectivity was analyzed, and the activities of a 40% Ni catalyst and a commercial catalyst were compared. As a result of experiment, In the case of a 40 wt% catalyst, the maximum CO2 conversion rate showed 77% at the reaction temperature of 400℃. Meanwhile, the commercial catalyst showed a maximum CO2 conversion rate of 60% at 450℃. When 50% of CO was added to the CO2 methanation reaction, the CO2 conversion rate was increased by about 5%. This is considered to be due to the atmosphere in which the CO reaction can occur without the process of converting to CH4 after forming carbon and CO as intermediates in terms of the CO2 mechanism on the catalyst surface.

• Bulletin of the Korean Chemical Society
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• v.6 no.5
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• pp.287-291
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• 1985

The addition of poly(styrenesulfonate) (PSS) to $Ru(bpy)_3^{2+}$ solutions shifted the emission peak by 3 nm to red, and increased emission intensity by 1.8 times. By contrast, poly(vinylsulfonate) (PVS) had little effect on the fluorescence spectrum. The effects of PSS on the spectral properties of $Ru(bpy)_3^{2+}$, were attributed to the presence of a hydrophobic phenyl group in PSS, which interact with $Ru(bpy)_3^{2+}$ by, at least in part, hydrophobic effect. The binding constant of $Ru(bpy)_3^{2+}$ to PSS in 0.1 M NaCl was $6{\times}10^4\;M^{-1}$, and this value was about $10^3$ times higher than those of methyl viologen ($MV^{2+}$) and $Cu^{2+}$. The Stern-Volmer constants of emission quenching of $Ru(bpy)_3^{2+}$ by $MV^{2+}$ and $Cu^{2+}$ in 0.1 M NaCl solutions were 426 and 40 $M^{-1}$, which correspond to second order rate constants($k_q$) of $1.1{\times}10^9\;and\; 1.0{\times}10^8\;M^{-1}s^{-1}$, respectively. The presence of PSS enhanced $K_{SV's}\;by\;{\sim}50$ times, whereas PVS increased the values only 1-4 times. The large enhancing effect of PSS, despite of lower charge density than PVS, was explained in terms of longer life-time of photoexcited $Ru(bpy)_3^{2+}$ bound to PSS and strong association of $Ru(bpy)_3^{2+}$ to PSS due to a specific interaction involving hydrophobic effect. The variation of $K_{SV's}$ on the concentrations of PVS and PSS were also investigated for $Ru(bpy)_3^{2+}-MV^{2+}\;and \;Ru(bpy)_3^{2+}-Cu^{2+}$ photoredox systems.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1471-1478
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• 2022

2'-Fucosyllactose (2'-FL), the most abundant fucosylated oligosaccharide in human milk, has multiple beneficial effects on human health. However, its biosynthesis by metabolically engineered Escherichia coli is often hampered owing to the insolubility and instability of α-1,2-fucosyltransferase (the rate-limiting enzyme). In this study, we aimed to enhance 2'-FL production by increasing the expression of soluble α-1,2-fucosyltransferase from Helicobacter pylori (FucT2). Because structural information regarding FucT2 has not been unveiled, we decided to improve the expression of soluble FucT2 in E. coli via directed evolution using a protein solubility biosensor that links protein solubility to antimicrobial resistance. For such a system to be viable, the activity of kanamycin resistance protein (Kan^R) should be dependent on FucT2 solubility. Kan^R was fused to the C-terminus of mutant libraries of FucT2, which were generated using a combination of error-prone PCR and DNA shuffling. Notably, one round of the directed evolution process, which consisted of mutant library generation and selection based on kanamycin resistance, resulted in a significant increase in the expression level of soluble FucT2. As a result, a batch fermentation with the ΔL M15 pBCGW strain, expressing the FucT2 mutant (F#1-5) isolated from the first round of the directed evolution process, resulted in the production of 0.31 g/l 2'-FL with a yield of 0.22 g 2'-FL/g lactose, showing 1.72- and 1.51-fold increase in the titer and yield, respectively, compared to those of the control strain. The simple and powerful method developed in this study could be applied to enhance the solubility of other unstable enzymes.

• YAKHAK HOEJI
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• v.31 no.6
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• pp.370-375
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• 1987

1, 4-Benzodiazepin 5-one was prepared from 2-aminobenzamide derivatives by acid catalyzed intermolecular cyclization. N-Alkylation of 2-aminobenzamide with $\alpha$-bromo acetaldehyde diethylacetal to 2(2', 2'-diethoxyethyl) aminobenzamide (I) and subsequent treatment of I with acid gave 1, 4-benzdiazepin 5-one, where as the acetyl derivatives of I did not react to 1, 4-benzodiazepin 5-one but to methyl 4-quinazolone (IV).

• The Korean Journal of Pharmacology
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• v.11 no.1 s.17
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• pp.27-31
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• 1975

1. The isolated strips of guinea-pig, fowl and reptiles (snake and tortoise) showed consistenly excitatory responses to $PGE_1\;and\;E_2$, which were dose-dependent. 2. Frog intestine revealed inhibitory responses to both $PGE_1\;and\;PGE_2$ except a small of $PGE_2$ (1-10 ng/ml) caused slight contraction. 3. The intestines of pieces showed inconsistent responses to $PGE_1\;and\;E_2$. In fresh-water fish(carp), $PGE_1$ produced relaxation under the dose of 50 ng/ml, and contraction by the large doses, but $PGE_2$ consistently caused contraction in dose-dependent manner. However, the strips of sea-water fish revealed the different responses to PGE compound: $PGE_1$ caused relaxation and $PGE_2$ conversly contraction even though in small degree. 4. These results that there are genera differences in the responses of the longitudinal strips of intestine to $PGE_1\;and\;PGE_2$ was assumed to be possibly correlated with evolutionally primitive function of gut.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.2
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• pp.62-64
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• 2006

The emerging peer-to-peer (P2P) model has recently gained a significant attention due to its high potential of sharing various resources among networked users. Super-peer based unstructured P2P systems have been found very effective by dividing the peers into two layers, super-peer and ordinary-peer Super-peers deal with all queries instead of ordinary-peers. The existing P2P systems assume all super-peers have equal responsibility and capabilities even if all super-peers have relative advantages and disadvantages. In this paper, we suggest the ISP2P (Intelligent Super-peer based P2P) which allows to select the best super peer to ordinary-peers. We classify super peers according as the capacity of an ordinary-peer a super-peer. We show that these considerations could improve the performance of the response time and Provide higher quality results to all peers in the network.

• Bulletin of the Korean Chemical Society
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• v.2 no.4
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• pp.132-138
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• 1981

Ab initio molecular orbital calculations have been performed in an effort to determine which types of chemical interactions play essential roles for the system, , $H_2O+CH_2SH^+$, and $H_2O+ CH_2S$. The most important contribution to the interaction energy in controlling reaction path is the exchange repulsion energy, EX, which is largely responsible for the shape of the total interaction energy curve. In the ion-molecule reaction, prior protonation of thioformaldehyde or prior deprotonation of water leads to formation of the corresponding ionic adducts ($H_2O+CH_2SH$ and $HOCH_2S^-$), with no barrier to reaction, simulating specific acid and base catalysis, respectively, as in the case of formaldehyde. Otherwise, approach of water to thioformaldehyde gives rise to a completely repulsive interaction.