• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.153-154
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• 2006

The development of metal catalysts that can polymerize or copolymerize "polar" $Ch_2=CHX$ monomers by insertion mechanisms would significantly expand the scope of metal-catalyzed polymerization and enable the synthesis of new materials with enhanced properties. We have studied the reactions of single-site olefin polymerization catalysts with vinyl chloride, acrylonitrile, and vinyl ethers, in order to probe monomer coordination trends, insertion rates and regioselectivity, and the structures and reactivity of metal alkyls that contain functional groups on the alpha and beta positions of the alkyl chain. These studies provide insights to the key issues that underlie the "polar monomer" problem. Copolymerization of olefins and selected vinyl ethers has been achieved.

• Current Applied Physics
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• 제18권12호
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• pp.1507-1512
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• 2018

The development of an organic-based aqueous redox flow battery (RFB) using quinone as an electroactive material has attracted great attention recently. This is because this battery is inexpensive, produces high energy density, and is environment friendly in stationary electrical energy storage applications. Herein, we investigate the redox potentials and solubilities of indole-5,6-quinone and indole-4,7-quinone derivatives in terms of the substituent effects of functional groups using theoretical calculations. Our results indicate that full-site substituted derivatives of indolequinone are more useful as active materials compared to single-site substituted derivatives. In particular, our calculations reveal that the substitution of $-PO_3H_2$ and $-SO_3H$ functional groups with multiple polar bonds is very effective in increasing the activity of the aqueous RFB. As a strategy to overcome the limitation that the aqueous solubility is intrinsically low because they are organic molecules, we suggest the substitution of functional groups with multiple polar bonds to the backbones of active organic materials. Among 180 indolequinone derivatives, 17 candidates that meet the redox potential standards ($${\leq_-}0.2V$$ or $${\geq_-}0.9V$$) and eight candidates with solubility exceeding 2 mol/L are identified. Three indolequinone derivatives that satisfy both conditions are finally presented as promising electroactive candidates for an aqueous RFB.

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.188-192
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• 2007

In this work, the effects of chemical treatment of polyimide films were studied by FT-IR, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angles. The adhesion characteristics of the films were also investigated in the peel strengths of polyimide/aluminum films. The increases of surface functional groups of KOH-treated polyimide films were greatly correlated with the polar component of surface free energy. The peel strength of polyimides to metal substrate was also greatly enhanced by increasing the KOH treatment time, which can be attributed to the formation of polar functional groups on the polyimide surfaces, resulting in enhancement of the work of adhesion between polymer film and metal plate.

• Carbon letters
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• 제11권4호
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• pp.298-303
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• 2010

A method of functionalization of multi-walled carbon nanotube (MWNT) at room temperature using dry ozone gas is described. The resulting MWNT were characterized by Fourier transform infrared, x-ray photoelectron spectroscopy, and scanning electron microscopy. Combined to these analyses and solubility in liquids, it could be concluded that the dry ozone gas exposure introduces polar functional groups such as carboxylic groups to MWNT similar to acidic modification of MWNT. Particularly, the stable dispersion of MWNT in water after ozone treatment above a critical level could be obtained, implying potential bio-application. The hydrophilic functional groups on the MWNT introduced by ozone oxidation were helpful in improving the interaction with functional groups in PA6 such as $-NH_2$ and -CONH- resulting in improved mechanical properties.

• 한국포장학회지
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• 제9권1호
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• pp.1-6
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• 2003

The partitioning behavior of five printing ink solvents was studied in various cookie ingredients before and after baking which had different water content and different structure. Solvents were ethyl acetate, hexane, isopropanol, methyl ethyl ketone, and toluene which represent different characteristic functional groups. Gas chromatography (G.C.) was used to measure partitioning values at $25^{\circ}C$ on each raw and baked cookie ingredients. Baking condition of cookie ingredients was $260^{\circ}C$ for 10 min. In cookie ingredients, decreases in water content generally affected Kp of polar solvents, but did not affect that of the non-polar solvents. However, as water content decreased in the cookie ingredient, the Kp of the non-polar and polar solvents showed mixed results.

• Genomics & Informatics
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• 제17권1호
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• pp.5.1-5.9
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• 2019

The chinstrap (Pygoscelis antarcticus) and gentoo (P. papua) penguins are distributed throughout Antarctica and the sub-Antarctic islands. In this study, high-quality de novo assemblies of blood transcriptomes from these penguins were generated using the Illumina MiSeq platform. A total of 22.2 and 21.8 raw reads were obtained from chinstrap and gentoo penguins, respectively. These reads were assembled using the Oases assembly platform and resulted in 26,036 and 21,854 contigs with N50 values of 929 and 933 base pairs, respectively. Functional gene annotations through pathway analyses of the Gene Ontology, EuKaryotic Orthologous Groups, and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were performed for each blood transcriptome, resulting in a similar compositional order between the two transcriptomes. Ortholog comparisons with previously published transcriptomes from the $Ad{\acute{e}}lie$ (P. adeliae) and emperor (Aptenodytes forsteri) penguins revealed that a high proportion of the four penguins' transcriptomes had significant sequence homology. Because blood and tissues of penguins have been used to monitor pollution in Antarctica, immune parameters in blood could be important indicators for understanding the health status of penguins and other Antarctic animals. In the blood transcriptomes, KEGG analyses detected many essential genes involved in the major innate immunity pathways, which are key metabolic pathways for maintaining homeostasis against exogenous infections or toxins. Blood transcriptome studies such as this may be useful for checking the immune and health status of penguins without sacrifice.

• Korean Chemical Engineering Research
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• 제44권6호
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• pp.644-649
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• 2006

본 연구에서는 다양한 조건에서 기체상태의 오존처리된 활성탄소를 이용하여 수용액 상태에서의 Cr(VI)의 흡착특성에 대하여 고찰하였다. 오존처리된 활성탄소의 표면특성의 변화는 pH, 산도-염기도, FT-IR을 이용하였으며, $N_2$/77K 등온 흡착특성은 BET식, Boer의 t-plot, 그리고 Horvath-Kawazoe의 slit pore model을 이용하여 확인하였다. 또한, 총 Cr의 흡착량은 ICP-AES를 이용하여 확인하였다. 실험 결과, 오존처리는 활성탄소의 표면에 산소를 함유한 극성 관능기를 증가시켰으며, 이로 표면산도 또한 증가되었다. 한편, 오존처리의 영향으로 보이는 활성탄소의 비표면적과 미세기공 부피의 감소가 관찰되었지만, 활성탄소의 총 Cr 흡착량은 오존처리 시간이 증가할수록 비례적으로 증가하였다. 이는 활성탄소의 Cr 흡착특성이 비표면적보다 상대적으로 표면에 형성된 극성 관능기의 영향을 크게 받는 것으로 판단된다.

• Korean Chemical Engineering Research
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• 제47권1호
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• pp.59-64
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• 2009

본 연구에서는 대기압 플라즈마를 이용하여 polylactic acid(PLA) 필름의 표면 특성 변화를 알아보았다. 극성 용매인 물과 비극성 용매인 Diiodomethane을 사용하여 표면의 접촉각을 측정하고, 이 값을 이용해 표면자유에너지 값을 계산하였다. 또한 대기압 플라즈마의 처리 조건에 따른 PLA 필름의 접촉각과 표면자유에너지 값을 최적화하였다. 그 결과 대기압 플라즈마 처리 시간 30 sec, RF-power 70 W, Ar 가스 유량은 6 lpm, 공기 중의 노출 시간은 5 min이었을 때가 가장 낮은 물 접촉각을 나타내었고, 표면자유에너지는 가장 높은 값을 나타내었다. XPS 분석을 통해서 대기압 플라즈마 처리 전 후 PLA 필름의 화학적 관능기의 변화를 분석하였으며, PLA 표면에 -C=O, -CO, -COO 등의 변화를 관찰하였다.

• Journal of Microbiology and Biotechnology
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• 제27권8호
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• pp.1472-1482
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• 2017

Bacterial cytochrome P450 (CYP) steroid hydroxylases are effectively useful in the pharmaceutical industry for introducing hydroxyl groups to a wide range of steroids. We found a putative CYP steroid hydroxylase (BaCYP106A2) from the bacterium Bacillus sp. PAMC 23377 isolated from Kara Sea of the Arctic Ocean, showing 94% sequence similarity with BmCYP106A2 (Bacillus megaterium ATCC 13368). In this study, soluble BaCYP106A2 was overexpressed to evaluate its substrate-binding activity. The substrate affinity ($K_d$ value) to 4-androstenedione was $387{\pm}37{\mu}M$. Moreover, the crystal structure of BaCYP106A2 was determined at $2.7{\AA}$ resolution. Structural analysis suggested that the ${\alpha}8-{\alpha}9$ loop region of BaCYP106A2 is intrinsically mobile and might be important for initial ligand binding. The hydroxyl activity of BaCYP106A2 was identified using in vitro enzyme assays. Its activity was confirmed with two kinds of steroid substrates, 4-androstenedione and nandrolone, using chromatography and mass spectrometry methods. The main products were mono-hydroxylated compounds with high conversion yields. This is the second study on the structure of CYP106A steroid hydroxylases, and should contribute new insight into the interactions of bacterial CYP106A with steroid substrates, providing baseline data for studying the CYP106A steroid hydroxylase from the structural and enzymatic perspectives.

• 공업화학
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• 제8권3호
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• pp.510-516
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• 1997

Cetyl alcohol과 polyoxyethylene(20) sorbitan monooleate를 혼합한 유화제와 양친매성 resin을 용매에 용해시킨 분산상에 분산매인 물을 첨가하여 O/W 에멀젼을 제조하여 HLB(Hydrophilic Lipophilic Balance) 값과 온도변화에 따른 상변화를 관찰하였다. 양친매성 resin을 함유한 에멀젼은 이를 함유하지 않는 에멀젼보다 온도변화에 따른 상안정성이 좋다는 것을 알 수 있었다. 또한 양친매성 resin이 에멀젼 안정성에 미치는 영향을 파악하기 위해 양친매성 resin에 함유되어 있는 작용기중 하나의 작용기를 갖는 resin을 model compound로 하여 HLB값과 온도변화에 따른 에멀전 상거동을 관찰한 결과, Poly(acrylic acid)