• Membrane Journal
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• v.32 no.5
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• pp.325-335
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• 2022

In this study, zeolitic imidazolate framework-9 (ZIF-9) was synthesized and Pebax/ZIF-9 mixed membranes were prepared by varying the content in poly(ether-b-amide)-1657 (Pebax-1657), and then a single gas (N₂, CO₂) was permeated to investigate the gas permeation characteristics of the mixed membrane. As the ZIF-9 content incorporated into the pure Pebax membrane increased, the N₂ permeability gradually decreased, and the CO₂ permeability increased up to the Pebax/ZIF-9 3 wt% mixed membrane, and then decreased at the content thereafter. And among the mixed membranes, the Pebax/ZIF-9 3 wt% mixed membrane showed the highest selectivity of 69.3 by selectively accepting CO₂ as the gate-opening phenomenon occurred for the polar gas, CO₂. In addition, both the CO₂ permeability and the CO₂/N₂ selectivity increased, resulting in the closest Robeson upper-bound.

• The Korean Journal of Mycology
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• v.17 no.3
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• pp.105-113
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• 1989

For selective purification of proteins in Pleurotus cornucopiae, affinity chromatography was performed by p-aminoanilinylsuccinyl-AH-Sepharose 4B gel synthesized by treating p-phenylene diamine with succinyl-AH-Sepharose 4B, which was prepared by treating AH-Sepharose 4B with succinic anhydride. The capacity of p-aminoanilinyl ligand group was 6.1 micromole per milliliter of gel. Total apparent molecular weight of the affinity proteins eluted from the synthesized gel was 167 KD, which were a protein complex of 130 KD and 37 KD. The contents of the nonpolar, polar, positively and/or negatively charged amino acids in the affinity protein were 44.57%, 24.75%, 21.25%, and 9.43%, respectively. Total apparent molecular weight of the affinity proteins eluted from the AH-Sepharose 4B gel was 95.2 KD, which were a protein complex of 61 KD, 31 KD and 3.2 KD. The contents of the nonpolar, positively and/or negatively charged amino acids in the affinity protein by AH-Sepharose 4B gel were 44.05%, 29.13%, and 12.91% respectively.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.556-564
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• 2018

In this study, polyethylene oxide (PEO)/polyethylene-co-vinyl acetate (EVA)/multi-walled carbon nanotube (MWCNT)-COOH composite membranes were prepared by adding 1, 2, 3, and 5 wt% of MWCNT-COOH to PEO/EVA respectively. The gas permeation properties of $N_2$, $O_2$ and $CO_2$ at $30^{\circ}C$ and 4~8 bar pressure were investigated. In each PEO/EVA/MWCNT-COOH composite membranes, the permeability of $CO_2$ increased with increasing the pressure, but the permeability of $N_2$ and $O_2$ were independent of the feeding pressure. As the MWCNT-COOH content increased, the $CO_2$ permeability increased and then decreased above 2 wt% MWCNT-COOH content. The 2 wt% MWCNT-COOH composite membrane exhibited a $CO_2/N_2$ selectivity of 77.8 and a $CO_2$ permeability of 84 barrer at 8 bar. The high $CO_2/N_2$ selectivity and $CO_2$ permeability were due to the high affinity between the quadrupolar $CO_2$, polar ether groups of PEO, and the polar ester groups of EVA. Additionally, the strong affinity between $CO_2$ and the -COOH groups on the MWCNT surface contributed to the high permeability of $CO_2$.

• Polymer(Korea)
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• v.32 no.2
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• pp.138-142
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• 2008

Molecularly imprinting technology is an effective method to prepare a synthetic material with a high selectivity to a target molecule. In this study, a molecularly imprinted polymer (MIP) was synthesized via UV-polymerization using theophylline and UV-curable polyester-acrylate resin as a template molecule and a crosslinker, respectively. To elucidate the effects of functional monomer type on the performance of the MIP, each MIP was synthesized using mathacrylic acid, acrylic acid, and acryl amide as functional monomers. Each MIP showed higher rebinding capacity to theophylline than its corresponding non-imprinted polymer (NIP). The MIP synthesized using mathacrylic acid as a functional monomer showed the highest rebinding capacity to theophylline. The selectivity of the MIP was investigated using a solution with caffeine having a very similar structure to theophylline. The binding performance of the MIP to theophylline decreased when distilled water was used as a solvent, which has more polarity than chloroform.

• The Korean Journal of Mycology
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• v.16 no.3
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• pp.121-127
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• 1988

For selective purification of protein in Pleurotus cornucopiae (Per.) Rolland, affinity chromatography was performed by benzoyl-AH-Sepharose 4B gel synthesized using AH-Sepharose 4B with starting materials. Ligand capacity of benzoyl group was 9.3 micromole per milliliter of gel. Total apparent molecular weight of affinity protein was 255KD, which were protein complex of 29.5, 31.5 34.0, 71.0 and 89.0KD, respectively. The contents of nonpolar, polar, positively charged, and negatively charged amino acid were 45.68%, 26.93%, 11.81% and 15.58%, respectively. The nonpolar protein was selectively purified by hydrophobic ligand of benzoyl group of gel.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.346-350
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• 2009

Natural state materials contain a lot of available nutrient components. Among them, natural nutrient substances are utilized not only as the ingredient of functional foods but also as the excipients of functional cosmetics and pharmaceutic. Of these nutrient substances, solubility parameters of each components were calculated to choose the most suitable solvents for solutions. The solubility parameters for each components were composed of the dispersion contribution of the molecular attractive function, the polar contribution of the molecular attractive function and the contribution of the hydrogen bonding force. The chi parameters ($\chi_{12}$) were calculated with the information of the solubility parameter for the solute and solvent and were used as the criteria for the optimal solute-solvent pair. The optimal solvents were suggested with the numerical values of chi parameters for some amino acids.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.42-47
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• 2004

This research has improved the problem of discharge AND gate PDP proposed before. The polarity of the DC discharge which composes AND gate is reversely designed and the cross talk problem to the adjacent scanning electrode has been improved. The AND gate proposed before operated by using non-linearity of the discharge by the space charge. In this research, new discharge NOT logic in which it was used that an applied voltage changed with the discharge circuit was added to AND gate. AND gate came to operate more stably. A selective address was able to be discharged with four horizontal scanning electrodes from the experiment result. The operation margin of the AND gate discharge obtained 34V and of the address discharge obtained 70V.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.239-245
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• 2004

A hue-based noise-tolerant corner detector is proposed for the exact detection of the real corners in spite of the shadows and random noise. Based on the fact that the hue gradient at the border of the opaque objects' shadow is smaller than the intensity gradient in HSI (hue-saturation-intensity) color space, the effects of shadow are eliminated by introducing the hue-weighted combination of vector gradient to the proposed corner detector. Furthermore, the proposed corner detector is robust to random noise by offsetting the contribution to the corner candidate when the polarities of the color gradients of the pixel pairs are out of phase each other. Results of the experiment show that the proposed corner detector can effectively detect the real corners.

• KSBB Journal
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• v.16 no.4
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• pp.327-331
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• 2001

Catechin compounds from the Green tea cultivated in Bosung (Chollanamdo) were extracted using supercritical fluid and various additives, and analyzed by reversed-phase high performance liquid chromatography (RP-HPLC). The chromatographic column was packed with LiChrospher 100RP-18(15 $\mu$m), and water was used as the mobile phase with 0.05% phosphoric acid and acetonitrile. Gradient election was applied to separate EGCG by changing the mobile phase compositions. Comparing the extraction yield of three different types of supercritical fluids, pure CO$_2$, with additives of water and ethanol (5 wt,%), the extraction amount of EGCG was most abundant in the suprcritical CO$_2$with ethanol. However, more was extracted and pure higher purity was achieved by solvent extraction using ethanol.

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.55-63
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• 1987

The systematic investigation of the retention behaviors of 18 monosubstituted benzenes in reversed-phase liquid chromatography(RPLC) was studied in order to predict the separation possibility of their mixtures and study the contribution of substituent group to the retentions of solutes. The columns and mobile phases employed in this study were $\mu$ -Bondapak $C_{18}$, $\mu$-Bondapak phenyl columns and methanol/water, acetonitrile/water, and THF/water, respectively. The polar substituents such as phenol, aniline, acetophenone and benzonitrile have smaller capacity factor(k') values than benzene, while nonpolar ones such as alkylbenzenes and halobenzenes show larger k' value. The capacity factors of all solutes increased on both C18 bonded and phenyl bonded phases as the organic solvent content of three organic solvent-water mixtures decreased. The absolute differences in capacity factor(${\Delta}k$') between substituent and benzene were graphically shown for the prediction of the separation of the mixture and interpretation of the elution behavior of substituent. In addition, the selectivity of solvent system for the separation of the mixture was investigated in both two columns and three mobile phases.