• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.667-671
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• 2006

The new MPV-type reagents, B-acetoxydiisopinocampheylborane ($Ipc _2$BOAc) and B-trifluoroacetoxydiisopinocampheylborane $(Ipc _2BO _2CCF _3)$, have been prepared and their reducing characteristics in the reduction of carbonyl compound have been examined in order to find out a new reducing system with unique applicability in organic synthesis. In general, the reactivity of $Ipc _2BO _2CCF _3$ appears to be stronger than that of $Ipc _2$BOAc, presumably due to the acidity increase by the electron-withdrawing fluorine-substituent. Both reagents show an excellent selectivity in 1,2-reduction of $\alpha,\beta$-unsaturatedcarbonyl compounds and in competitive reduction between structurally different carbonyl compounds. In addition, $Ipc _2BO _2CCF _3$ shows interesting features in the stereoreduction of cyclic ketones.

• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.506-514
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• 2007

To select the best oxygen carrier particle for syngas fueled chemical-looping combustor, the reduction reactivity and carbon deposition characteristics were determined in a thermogravimetric analyzer. Four kinds of oxygen carrier particles (NiO/bentonite, $NiO/LaAl_{11}O_{18}$, $Co_xO_y/CoAl_2O_4$, $NiO/NiAl_2O_4$) were tested with the simulated syngas (30% $H_2$, 10% $CO_2$, 60% CO) as a reduction gas. With each of these particles, the maximum conversion and oxygen transfer capacity increase with increasing the reduction temperature At the given experimental range, the optimum operating temperature to maximize oxygen transfer rate is found to be $900^{\circ}C$ and carbon deposition on the particles could avoid at the temperature above $800^{\circ}C$. Among four kinds of oxygen carrier particles, the NiO-based particles exhibits better reactivity than the CoO-based particle. Moreover, the NiO/bentonite particle produces the best reactivity based on the oxygen transfer rate and the degree of carbon deposition. The measured oxygen transfer rate increases as the metal oxide content in NiO/bentonite particle is increased thereby higher metal oxide contents could provide stable operation of chemical-looping combustor.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.262-264
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• 2009

Ternary oxides with controlled band gap energy and reduced reactivity against moisture and carbon dioxide gas were designed and studied as a potential material for protective layer of ac-PDPs. The results showed a significant reduction in firing voltage and improved environmental stability.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.137-142
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• 1999

소형원자로는 크기가 작아서 경제성이 떨어지는 단점이 있지만 안전성이 높아 수출용 원자로로서 가능성이 높다. 소형원자로의 이용 범위는 지역난방용 원자로, 담수화플랜트, 선박 및 잠수함의 추진용 원자로 그리고 우주 탐사용 원자로 등으로 확대되었으며 다양한 형태로 개발되었다. 소형원자로 개발에 있어서 주기길이 연장은 핵연료주기 경제성에 매우 큰 영향을 미친다.(중략)

• Archives of Pharmacal Research
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• v.28 no.9
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• pp.1002-1012
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• 2005

5-Substituted 4-oxo-2-thioxo-1,,2,3,4-tetrahydropyrimidine were synthesized by interaction of 4­oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-sulfonylhydrazide with some aldehydes to give the corresponding Schiff-bases, which after cyclization gave corresponding thiazolidinones. For some of the thiazolidinones, Mannich bases reaction was carried out. All the derivatives were tested for their possible inhibitory effect on Schistosoma mansoni cercarial elastase (CE). Only, N'-(4-methylbenzyledine)-4-oxo-2-thioxo-1,2 ,3,4-tetrahydropyrimidine-5-sulfonylhydrazide was found to have potent inhibitory effect on the CE activity with $IC_{50} = 264{\mu}M.$ Upon its use as a paint for mice tails before infection with S. mansoni cercariae, the compound formulated in jojoba oil caused a significant reduction ($93\%$; P-value = 0.0002) in the worm burden. IgG & IgM in mice sera were measured by using several S. mansoni antigens by ELISA. Sera from treated infected mice (TIM) 2, 4, and 6 weeks (W) post infection (PI) showed 1.2 folds lower, 1.2 folds higher, 1.7 folds lower IgM reactivity against soluble cercarial antigenic preparation (CAP), respectively, when compared with sera collected from infected untreated mice (IUM). Sera from TIM 2, 4, and 6WPI showed 1.3, 1.6, and 1.7 folds higher IgG reactivity, respectively against CAP than the IgG reactivity from IUM. Sera from TIM 2, 4 and 6WPI showed 1.5, 1.2 folds lower and 1.4 folds higher IgM reactivity, respectively against soluble worm antigenic preparation (SWAP) when compared with sera collected from IUM. Sera from TIM 2, 4, and 6WPI showed 1.4, 1 folds lower and 1 fold higher IgG reactivity, respectivley to SWAP when compared with sera from IUM. Sera from TIM 2, 4, and 6WPI had generaly lower IgM and IgG reactivities against soluble egg antigen (SEA) when compared with sera from IUM.

• Journal of Electrochemical Science and Technology
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• v.4 no.2
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• pp.71-80
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• 2013

The study of methyl viologen ($MV^{2+}$) mediated oxygen reduction in electrolytic ethanol media possesses potential application in the electrochemical synthesis of hydrogen peroxide mainly due to the advantages of the much increased solubility of molecular oxygen ($O_2$) and high degree of reversibility of $MV^{2+/{\bullet}+}$ redox couple. The diffusion coefficients of both $MV^{2+}$ and $O_2$ were investigated via electrochemical techniques. For the first time, $MV^{2+}$ mediated $O_2$ reduction in electrolytic ethanol solution has been proved to be feasible on both boron-doped diamond and micro-carbon disc electrodes. The electrocatalytic response is demonstrated to be due to the radical cation, $MV^{{\bullet}+}$. The homogeneous electron transfer step is suggested to be the rate determining step with a rate constant of $(1{\pm}0.1){\times}10^5M^{-1}s^{-1}$. With the aid of a simulation program describing the EC' mechanism, by increasing the concentration ratio of $MV^{2+}$ to $O_2$ electrochemical catalysis can be switched from a partial to a 'total catalysis' regime.

• Tribology and Lubricants
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• v.34 no.6
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• pp.226-234
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• 2018

Copper chemical mechanical planarization (CMP) has become a key process in integrated circuit (IC) technology. The results of copper CMP depend not only on the mechanical abrasion, but also on the slurry chemistry. The slurry used for Cu CMP is known to have greater chemical reactivity than mechanical material removal. The Cu CMP slurry is composed of abrasive particles, an oxidizing agent, a complexing agent, and a corrosion inhibitor. Citric acid can be used as the complexing agent in Cu CMP slurries, and is widely used for post-CMP cleaning. Although many studies have investigated the effect of citric acid on Cu CMP, no studies have yet been conducted on the interfacial friction characteristics and step height reduction in CMP patterns. In this study, the effect of citric acid on the friction characteristics and step height reduction in a copper wafer with varying pattern densities during CMP are investigated. The prepared slurry consists of citric acid ($C_6H_8O_7$), hydrogen peroxide ($H_2O_2$), and colloidal silica. The friction force is found to depend on the concentration of citric acid in the copper CMP slurry. The step heights of the patterns decrease rapidly with decreasing citric acid concentration in the copper CMP slurry. The step height of the copper pattern decreases more slowly in high-density regions than in low-density regions.

• The Journal of the Korean Society for Microbiology
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• v.18 no.1
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• pp.91-98
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• 1983

The effect of subcutanecus injection of Corynebacterium parvum($700{\mu}g$) on cellular and humoral immune responses when given at various time relative to sheep red blood cell(SRBC) sensitization were studied by the evaluation of Arthus, delayed-type hypersensitivity(DTH), rosette forming cell, hemagglutinin and hemolysin reactions. Arthus reactivity(3 hours) developed in control mice and test mice pretreated with C. parvum 8 days prior to intravenous sensitization with SRBC were similar. However, there was slight depression of reactivity when C. parvum was given subcutaneoutly(s.c.) 4 or 2 days prior to SRBC sensitization. Arthus reactivity was significantly depressed when C. parvum was given s.c. either at the same time as, or 2 days later than, antigen. DTH reaction was net depressed significantly when C. parvum was injected 8 or 2 days prior to SRBC sensitization or at the same time as antigen. In contrast DTH was significantly augmented when C. parvum given s.c. 4 days prier to SRBC sensitization. DTH was depressed when C. parvum was given s.c. 2 days after antigen. No significant change occurred in rosette forming percetages of spleen cell when C. parvum was given s.c. 8, 4 or 2 days before SRBC sensitization. In contrast, a significant reduction in percentages of rosette forming cell occurred when C. parvum was given s.c. either at the same time as, or 2 days later than, antigen. Serum hemaggulutinin and hemolysin titers were not significantly affected by subcutaneous injection of C. parvum regardless of time relative to SRBC sensitization. However, mercaptoethanol-resistant hemaggulutinin and hemolysin(IgG) titers were somewhat augmented when C. parvum was given 2 days after antigen. It is concluded from these results that depending on the time and route of inoculation, C. parvum can enhance or depress immune responses in mice, suggesting the time and route of C. parvum inoculation is an important point of concern about clinical use of C. parvum for the treatment of cancer.

• Clean Technology
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• v.20 no.3
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• pp.212-217
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• 2014

In order to regenerate the sulfidated desulfurization sorbent, oxygen is used as the oxidant agent on the regeneration process. The small amount of oxygen un-reacted in regeneration process is flowed into direct sulfur recovery process. However, the reactivity for $SO_2$ reduction can be deteriorated with the un-reacted oxygen by various reasons. In this study, the deactivation effects of un-reacted oxygen contained in the off-gas of regeneration process flowed into direct sulfur recovery process of hot gas desulfurization system were investigated. Sn-Zr based catalysts were used as the catalyst for $SO_2$ reduction. The contents of $SO_2$ and $O_2$ contained in the regenerator off-gas used as the reactants were fixed to 5.0 vol% and 4.0 vol%, respectively. The catalytic activity tests with a Sn-Zr based catalyst were for $SO_2$ reduction performed at $300-450^{\circ}C$ and 1-20 atm. The un-reacted oxygen oxidized the elemental sulfur produced by $SO_2$ catalytic reduction and the conversion of $SO_2$ was reduced due to the production of $SO_2$. However, the temperature for the oxidation of elemental sulfur increased with increasing pressure in the catalytic reactor. Therefore, it was concluded that the decrease of reactivity at high pressure is occurred by catalytic deactivation, which is the re-oxidation of lattice oxygen vacancy in Sn-Zr based catalyst with the un-reacted oxygen on the catalysis by redox mechanism. Meanwhile the un-reacted oxygen oxidized CO supplied as the reducing agent and the temperature in the catalyst packed bed also increased due to the combustion of CO. It was concluded that the rapidly increasing temperature in the packed bed can induce the catalytic deactivation such as the sintering of active components.

• Journal of environmental and Sanitary engineering
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• v.15 no.3
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• pp.88-93
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• 2000

The objective of this study was to depict the kinetic behavior of the platinum catalyst for the deep oxidation of VOCs and their mixture. The oxidation characteristics of VOCs, which were benzene, toluene, and styrene, was studies on a 0.5% $Pt/{\gamma}-Al_2O_3$ catalyst. The reactivity increases in order benzene>toluene>styrene. In mixtures, remarkable effects on reaction rate and selectivity have been evident ; the strongest inhibiting effect was shown by styrene and increases in a reverse order with respect to that of reactivity. The reaction model reveals that there is a competition between the two reactants for the oxidized catalyst. Thus, the nontoxic catalytic oxidation process was suggested as the new VOCs control technology.