• Korean Journal of Microbiology
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• v.32 no.1
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• pp.84-90
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• 1994

Kinetic parameters of various substrates and inhibitors were measured to elucidate the binding requirements of the active site of intracellular adenosine deaminase (ADA) in Aspergillus oryzae. 3'-Deoxyadenosine was the best substrate according to the value of relative kcat/$K_m$. Purine riboside was found to be the strongest inhibitor with the $K_i$ value of $3.7{\times}10^{-5}$M. Adenine acted neither as a substrate nor as an inhibitor, suggesting the presence of ribose at N-9 of adenosine was crucial to binding. ADA also catalyzed the dechlorination of 6-chloropurine riboside, generating inosine and chloride ions. Substrate specificity of 6-chloropurine riboside was 0.86% of adenosine. Purine riboside, a competitive inhibitor of ADA, inhibit the dechlorination with similar $K_i$ value, suggesting that the same binding site was involved in deamination and dechlorination. Among the sulfhydryl group reagents, mercurials, pchloromercuribenzoate (PCMB), mersalyl acid and $HgCl_2$ inactivated the enzyme. Mersalyl acid-inactivated ADA was reactivated by thiol reagents, but PCMB-inactivated enzyme was not. When ADA was treated with the mercurial reagents, the inhibition constants and inhibition patterns were determined. Each inhibition was competitive with substrate. The $K_i$ values of these mercurial reagents were lower in 10 mM phosphate buffer than in 100 mM phosphate buffer, showing phosphate dependency.

• International Commerce and Information Review
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• v.18 no.2
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• pp.151-167
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• 2016

This study is focus on the relationship between the role of FTA and service trade performance enhancing strategy in Korea. and It is on the verification of the focus to the competitive promoting strategy of the logistics industry. finally proposition of the policy making to the government is proposed in the research. The invigoration of the service trade through FTA focus on the logistics industry is very combinative economy policy target with the side of government and the side of private enterprises both. added to this, this is the goal of impossible to achieve just with the development of logistics industry itself. it needs to construct the organic relationship, that is the implement and enforcement of the SCM through logistics industry network. Thus, on logistics, the 3rd party operating system implementation is top priority to gain international competitiveness. furthermore, the 4th party facilitation including consulting function and IT technology to pursue the maximum effectiveness logistics service providing.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.607-618
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• 2017

Harmful air pollutants are exhausted from the various industrial facilities including the coal-fired thermal power plants and these substances affects on the human health as well as the nature environment. In particular, nitrogen oxides ($NO_x$) and sulfur dioxide ($SO_2$) are known to be causative substances to form fine particles ($PM_{2.5}$), which are also deleterious to human health. The integrated system composed of selective catalytic reduction (SCR) and wet flue gas desulfurization (WFGD) have been widely applied in order to control $NO_x$ and $SO_2$ emissions, resulting in high investment and operational costs, maintenance problems, and technical limitations. Recently, new technologies for the simultaneous removal of $NO_x$ and $SO_2$ from the flue gas, such as absorption, advanced oxidation processes (AOPs), non-thermal plasma (NTP), and electron beam (EB), are investigated in order to replace current integrated systems. The proposed technologies are based on the oxidation of $NO_x$ and $SO_2$ to $HNO_3$ and $H_2SO_4$ by using strong aqueous oxidants or oxidative radicals, the absorption of $HNO_3$ and $H_2SO_4$ into water at the gas-liquid interface, and the neutralization with additive reagents. In this paper, we summarize the technical improvements of each simultaneous abatement processes and the future prospect of technologies for demonstrating large-scaled applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.6000-6007
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• 2013

Cr(VI)-heterocyclic complex[Cr(VI)-isoquinoline] was synthesized by the reaction between of heterocyclic compound(isoquinoline) and chromium trioxide, and characterized by IR and ICP analysis. The oxidation of benzyl alcohol using Cr(VI)-isoquinoline in various solvents showed that the reactivity increased with the increase of the dielectric constant(${\varepsilon}$), in the order : cyclohexene$CH_3$, m-Br, m-$NO_2$). Electron- donating substituents accelerated the reaction, whereas electron acceptor groups retarded the reaction. The Hammett reaction constant(${\rho}$) was -0.69(308K). The observed experimental data have been ratiolized. The hydride ion transfer causes the prior formation of a chromate ester in the rate-determining step.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.140-145
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• 2015

This study was aimed at analyzing NOx conversion characteristics in the HC-SCR with biodiesel content changes of the secondary fuel injection (BD0, BD10, BD25). Test conditions for temperature were set to $290^{\circ}C$, $320^{\circ}C$ and $350^{\circ}C$ considering the upstream temperature of a HC-SCR, distillation of the secondary injected fuels and etc. The amount of fuel injection was adjusted with a fixed space velocity of 55,000(1/h). According to the test results of distillation, the T90 was the same level about $350^{\circ}C$ on all test fuels and the amount of evaporation was reduced at lower than $350^{\circ}C$ temperature condition with increasing biodiesel content. As biodiesel content which is mixed with the secondary injected fuel is increased, NOx reduction efficiency was determined to decrease. The difference of the Nox reduction ratio in a high temperature condition($320^{\circ}C$ and $350^{\circ}C$) than the low temperature($290^{\circ}C$) was more significant. These results are thought to be poor evaporation properties (distillation) and high molecular weight of the biodiesel.

• Polymer(Korea)
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• v.37 no.2
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• pp.211-217
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• 2013

Potassium tert-butoxide (t-BuOK) with $CO_2$ or benzoyl chloride (BzC) as a polymerization initiator system was used with crown ether or TMAC as catalyst to synthesize very high molecular weight nylon 4 homo- and copolymers by anionic ring opening polymerization. Effect of different amounts of catalyst, crown ether and TMAC on the polymerization was studied in terms of intrinsic viscosity, yield and thermal properties. By adding crown ether or TMAC, polymers with very higher intrinsic viscosity values were obtained in a high yield. It was possible to synthesize nylon 4 homopolymer with such a high intrinsic viscosity value of 6.36 dL/g. Crown ether was found to be more efficient in terms of intrinsic viscosity and polymer yields than TMAC. Thermal analysis confirmed that molecular weight effect on the thermal properties of both nylon 4 and nylon 4 copolymer was marginal.

• Applied Biological Chemistry
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• v.41 no.5
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• pp.384-389
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• 1998

The herbicide propanil and its metabolite, DCA were incubated with oxidative catalysts in the presence or absence of humic monomers to evaluate the incorporation of them into humic substances. Propanil and DCA underwent little or no transformation by oxidatve catalysts in the absence of humic monomers. In the presence of humic monomers, the most effective co-substrate for transformation of propanil was syringic acid by laccase and HRP, that of DCA was catechol by laccase and HRP, and protocatechuic acid by birnessite. The transformation of DCA was the highest when it was incubated with catechol at pH 8.0 during 24 hrs by laccase, and with catechol at pH 3.0 during 2 hrs by HRP, and with protocatechuic acid at pH 5.0 during 2 hrs by birnessite. The DCA transformation increased with increasing concentration of humic monomers. The transformation of DCA was increased with about 5 times when it was incubated with lactase and birnessite together than lactase alone, but that of it was not effected when it was incubated with HRP and birnessite together. When DCA was incubated with dissolved organic carbon in the presence of oxidative catalysts, the transformation of it was not increased by laccase and birnessite but increased by HRP.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.629-636
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• 1990

Dephosphorylation of p-nitrophenyldiphenylphosphate(p-NPDPP) mediated by anions of sodium 2-alkylbenzimidazole-5-sulfonate(R-BI-SO$_3$Na) in CTABr micellar solutions are obviously slower than that by anion of sodium benzimidazole-5-sulfonate(BI-SO$_3$Na), and the reation rates were decreased with increase of lengths of alkyl groups. This presents a striking contrast to the reactions in aqueous solutions without added CTABr, of which the reaction rates are on approximately same levels. It seems due to steric effect of alkyl groups of R-BI$^-$SO$_3$Na in the Stern layer of micelle, and it is supported by measured activation parameters(△H$^\neq$/TEX>, △G$^\neq$/TEX> and △S$^\neq$/TEX>) of the reactions in aqueous and micellar solutions. In addition to nucleophilic ability of benzimidazole moiety of R-BI$^-$SO$_3$Na on the reactions, these compounds with long alkyl groups(nonyl to pentadecyl) are micellized for themseleves, and increase the reaction rates due to their micellar catalyses in aqueous solutions, not including CTABr.

• Polymer(Korea)
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• v.33 no.4
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• pp.290-296
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• 2009

The morphology and mechanical properties of epoxy/polyamide/MPD/2E4MZ-CN reactive blends with various amount of catalyst were investigated. The cure behaviors, mechanical strengths, and morphological changes of the epoxy blend systems were analyzed by using DSC, UTM, and SEM, respectively. The amount of catalyst ranged from 0 to 3 phr, and the cure reaction occurred at $170^{\circ}C$ for 30 min. The maximum peaks in heat flow during cure reactions appeared at slightly lower temperature with increasing catalyst content, indicating that the cure reactions start at lower temperature by adding catalyst and polyamide rarely hinders the cure reaction paths. The co-continuous morphology was found in epoxy/polyamide(20 phr) blends and by adding catalyst to the blends much clearer and uniform co-continuous phase was observed. The surface tension of the mechanical test specimen was increased due to the AP plasma surface treatment, and then adhesion strength was increased by over 20% by adding 2 phr of catalyst to the blends. When considering morphological tuning of the blends by means of catalyst incorporation, it is expected that the increased elongation and adhesion strength can be achieved in the structural adhesive systems.

• KSBB Journal
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• v.16 no.2
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• pp.188-199
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• 2001

A gene encoding the dextransucrase(dsCB) that synthesizes mostly $\alpha-(1\rightarrow6)$ linked dextran with low amount(10%) of $\alpha-(1\rightarrow3)$ branching was cloned and sequenced from Leuconostoc mesenteroides B-742CB. The 6.1 kbp DNA fragment carrying dsCB showed one open reading frame(ORF) composed of 4,536bp. The deduced amino acid sequence shows that it begins from the start codon(ATG) at position 698 of the cloned DNA fragment and extends to the termination condon(TAA) at position 5,223. The enzyme is consisted of 1,508 amino acids and has an calculated molecular mass of 168.6kDa. This calculated Mw was in good agreement with an activity band of 170kDa on non-denaturing SDS-PAGE. A recombinant E. coli DH5 $alpha$ harboring pDSCB produced extracellular dextransucrase in 2% sucrose medium, and synthesized both soluble and insoluble dextran. To compare the properties of enzyme with B-742CB dextransucrase, the acceptor reaction, hydrolysis of dextran and methylation were performed. The expressed enzyme showed the same properties as B-742CB dextransucrease, but its ability to synthesize $\alpha-(1\rightarrow3)$ branching was lower than that of B-742CB dextransucrase. In order to identify the critical amino acid residues known as conserved regions related to catalytic activity, Asp-492 was replaced with Asn. D492N resulted in a 1.6 fold decrease in specific activity.