• Bulletin of the Korean Chemical Society
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• v.6 no.3
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• pp.135-138
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• 1985

A new flexible $N_2O_2$-type tetradentate ligand, ethylene-diamine-N,N'-di-${\alpha}$-butyric acid (eddb), has been synthesized, and a series of cobalt (III) complexes of eddb, $[Co(edda)(L)]^{n+}$ (L = $Cl_2$, $(H_2O)_2$, $Cl\;H_2O$, and $Co^2_3$), have been prepared. Only s-cis isomers have been yielded during the preparation of complexes. Ring strain is cited as the primary cause for the preference for the s-cis geometric configuration.

• Polymer(Korea)
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• v.29 no.2
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• pp.172-176
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• 2005

Environmentally friendly water dispersion polyurethanes containing fluorine were prepared with a fluorinated polyol having $62\%$ of fluorine $(Fluorolink^{(R)}\;M_n\;1000)$. In order to control the fluorine contents of the synthesized polyurethanes polytetramethylene glycol (PTMG2000) and $Fluorolink^{(R)}$ were mixed at assigned ratios and reacted with isophorone diisocyanate (IPDI) as a diisocyanate used. Introducing hydrophilic anion to the polymer chain was achieved by applying dimethyl propionic acid (DMPA). The ionic groups were neutralized with triethyl amine (TEA) before dispersion into water. Chain extension was executed by adding ethylene diamine at the final stage. Mechanical properties of the polymers showed that modulus increased with increasing $Fluorolink^{(R)}$ content. Surface energy values obtained from contact angle measurement decreased with increasing $Fluorolink^{(R)}$ content up to $20\%$. We expect that the synthesized polyurethanes present reliable effect from the fluorine atoms incorporated even at a small amount of $Fluorolink^{(R)}$.

• Composites Research
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• v.28 no.5
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• pp.265-269
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• 2015

Development of simple and efficient method for large-scale production of mechanically strong and electrically conductive graphene fiber is highly desirable for practical applications, such as fiber-reinforced composites, wearable electronics, and electromagnetic irradiation shielding. Here, we present a facile approach for the preparation of amine-functionalized graphene fibers by simple wet-spinning of diamine-functionalized graphene oxide (GO-$NH_2$), which is used because of its synthetic convenience, good dispersity, and scalable production with low cost. The amine-functionalized graphene fiber shows high electrical and mechanical properties compared to pristine graphene oxide fiber due to the electrostatic interaction between amine groups and electronegative functional groups of graphene oxide.

• Membrane Journal
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• v.8 no.1
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• pp.29-41
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• 1998

Thin-film composite reverse osmosis membranes of aromatic polyamides were prepared by the interfacial polymerization. Aromatic polyamides as active skin layer were made from the interfacial polymerization of MPD(m-phenylene diamine) in the aqueous and TMC(trimesoyl chloride) in HCFC(1,1-dichloro-1-fluoroethane) organic solvent. The performances of the various reverse osmosis composite membranes prepared by changing processing variables were examined. The performance of membrane manufactured by batch system was varied with organic solvent, monomer concentration, dipping time, heat treatment temperature, acid acceptor, ethanol post treatment, and acid post treatment. Ethanol post treatment was the most dominant factors in increasing permeate amount, while the monomer concentration and dipping time were the main factors in increasing selectivity. The spiral-wound module was produced with the membrane prepared at optimum condition of the continuous process. Comparing the performance of this membrane module made here with that of commercial membrane module, the permeate flux was increased by 33% while the rejection was decreased by 5%.

• Polymer(Korea)
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• v.35 no.2
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• pp.171-175
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• 2011

Isophorone diisocyanate(IPDI), polytetramethylene glycol 1000 (PTMG1000), and N-methyl diethanol amine (MDEA) were applied to prepare cationic polyurethane water dispersions (PUD). Various neutralizers and chain extenders were introduced in order to investigate property changes, such as particle size, viscosity, $T_g$, tensile strength, and water swellability, depending on chemical structure of those chemicals. While the PUDs neutralized by acetic acid showed a typical elastomeric behavior, the others used with hydrochloride presented crystalline behavior. Among chain extenders isophorone diamine (IPDA) provided the best mechanical property. The particle size of the PUD neutralized with HCl was smaller than that with acetic acid. It is believed that this is attributed to the size difference of counter ions. The PUD chain-extended with hydrazine had the smallest particle size.

• Korean Journal of Microbiology
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• v.24 no.4
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• pp.370-376
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• 1986

From the outer membrane portion of Gram-negative Klebsiella pneumoniae, the activity of 2-furaldehyde dehydrogenase depending upon beta-nicotinamide adenine dinucleotide was detected. Cytoplasmic membrane was preferentially extracted from crude membrane with $Mg^{2+}$ and Triton X-100, and then outer membrane was collected by ultracentrifugation. The crude enzyme was obtained by solubilization of outer membrane with lysozyme, ethylene diamine tetraacetate and Triton X-100. Thereafter 2-furaldehyde dehydrogenase was partially purified through column chromatography on QAE-Sephadex Q-50 and Sephadex G-150 and the enzyme activity was analyzed by means of high performance liquid chromatography. The optimal pH for the activity of the enzyme was about 9.5 and the optimal temperature was about $85^{\circ}C$. The partially purified enzyme retained tis activity at $85^{\circ}C$ for 5 hours. The optimal concentration of Triton X-100 for the activity of the enzyme was about 1.5% in the reaction mixture.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2756-2760
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• 2011

To develop more advanced binaphthol derived CSPs, two new 1,1-bi-2-naphthol derived chiral stationary phases (CSPs) (CSP 1 and CSP 2) were prepared by connecting with silica gel at a hydroxy (OH) group of binaphthol. Previously reported two 1,1'-binaphthyl-2,2'-diamine derived CSPs (CSP 3 and CSP 4) were also prepared to compare the role of their functional groups (-OH and -$NH_2$) with CSP 1 and CSP 2. Enantioseparation of randomly selected, 11 chiral compounds on these four CSPs was performed and the results compared to each other. 3,5-Dinitrobenzoyl (3,5-DNB) derivatives of each CSP showed better results than the others and binaphthyldiamine derived CSP showed slightly better than binaphthol derived one.

• Macromolecular Research
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• v.12 no.4
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• pp.336-341
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• 2004

A new type of cross-linked methylaluminoxane (MAO)-supported cocatalyst has been prepared by the reaction of a soluble MAO and a cross-liking agent such as an aromatic diamine compound. The cross-linked MAO-supported cocatalyst was used for the polymerization of ethylene in the presence of bis(n-butylcyclopentadienyl) zirconium dichloride, (n-BuCp)$_2$ZrCl$_2$. The catalyst activity of (n-BuCp)$_2$ZrCl$_2$ cocatalyzed with the new supported cocatalyst was higher than that of the commercial silica-supported MAO (SMAO) cocatalyst. The molecular weight and the bulk density of the polyethylene produced by using the new supported cocatalyst were slightly higher than those of polyethylene synthesized using commercial SMAO. The resulting polyethylene particles possess spherical morphologies with very few fine particles.

• Journal of the Korean Magnetic Resonance Society
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• v.28 no.3
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• pp.15-19
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• 2024

1,1'-carbonyldiimidazole (CDI) is a versatile reagent that can be used for synthesizing a variety of organic compounds containing carbonyl functional groups. The reactivity of CDI with two ortho-substituted anilines was tested and characterized with analytic techniques such as NMR, IR, and ESIMS. A reaction of CDI with two equivalents of disubstituted aniline (N¹,N¹-diethylbenzene-1,2-diamine) formed a urea compound, 1,3-bis(2-(diethylamino)phenyl)urea (1). On the other hand, a reaction with one equivalent of mono-substituted aniline (tert-butyl (2-aminophenyl)carbamate) formed a substituted benzimidazolone, tert-butyl 2-oxo-2,3-dihydro-1H-benzo[d]imidazole-1-carboxylate (2). These results demonstrated that a singly substituted aniline prefers an intramolecular ring formation while an N,N-doubly-substituted aniline prefers a urea formation.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.191-191
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• 2003

가시광선영역에서 높은 광학적 투명도를 갖는 n-type 반도체인 ZnO 박막은 넓은 범위에서 응용되고 있다. 현재 ZnO 박막의 특성 향상을 위하여 여러 원소(Al, Ga)의 도핑을 시도하고 있다. 특히 Al-doped ZnO 박막은 sol-gel dip coating에 의해서도 높은 전기전도도와 투과율로 활발히 연구되고 있다 본 논문에서는 여러 도핑농도를 갖는 Al-doped ZnO 박막이 sol-gel dip coating법에 의해 준비되었다. Al-doped ZnO 박막은 zinc acetate [Zn($CH_3$COO$_2$)ㆍ2$H_2O$] powder 와 여러 도핑농도를 갖는 aluminum nitrate (Al(NO$_3$)$_3$ㆍ9$H_2O$) powder를 알코올에 용해하여 $H_2O$, Ethylene glycol, Ethylene diamine 등을 첨가하여 제조하였다 XRD와 SEM (Scanning electron microscope)이 막의 상형성 분석을 위해 이용되었으며, 가시광선 영역 투과율(UV/VIS spectrophotometer)과 표면전기저항(four point probe)이 주요 특성으로 분석되었다.