• Membrane Journal
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• v.23 no.4
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• pp.283-289
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• 2013

Poly(vinyl alcohol) (PVA) coating solution containing glutaraldehyde (GA) and maleic anhydride (MA) as crosslinking agents was coated onto hydrolyzed poly acrylonitrile (PAN) hollow fiber membranes. The permselectivities of the resulting composite membranes prepared varying the reaction temperature and the concentration of the crosslinking agents were tested for 90 wt% ethanol aqueous mixtures by the pervaporation technique at $60^{\circ}C$. In general, the flux decreased while the selectivity increased for the increases of the reaction temperature and the crosslinking concentration. In case of GA as a crosslinking, the flux $165g/m^2hr$ and the separation factor 81 were obtained at GA 11 wt% and the reaction temperature $120^{\circ}C$. And for the case of MA, the flux $174g/m^2hr$ and the separation factor 73 were obtained at MA 11 wt% and the reaction temperature $120^{\circ}C$.

• Membrane Journal
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• v.22 no.4
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• pp.272-279
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• 2012

The neutral polymer, poly (vinyl alcohol) (PVA), was coated onto polyamide (PA) thin film composite reverse osmosis (RO) membranes. And then these membranes were investigated for the model foulants, bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA) whether there are aome improvement. As the operating pressure increased with 2, 4, 8 atm for BSA, HA and SA 100 ppm in feed solution, the fouling phenomena was worse for both none and PSSA coated membranes. The fouling occurred in the sequence of BSA > HA > SA due to the interactions between PVA snd functional groups of foulants, and on the other hand the fouling reduction was observed in the order of HA > BSA > SA. The observation of scanning electron microscopy photographs showed the same trend. As a result, there should be the improvement of fouling phenomena for the PVA coated RO membranes and the case of HA was shown distinct.

• Membrane Journal
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• v.23 no.2
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• pp.144-150
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• 2013

In order to increase the permeabilities of $N_2$, $O_2$, $CH_4$, $CO_2$, $SO_2$, Poly (ether block amides) (PEBAX) 3533 and its blended membranes with Poly (ethylene glycol) (PEG) of molecular weight 400 were prepared. The contents of PEG400 were 20%, 40%, and 50% and this membranes were characterized in terms of permeability for $N_2$, $O_2$, $CH_4$, $CO_2$, $SO_2$ gases and also diffusivity and solubility as well by using the time-lag gas separation apparatus. As expected, the permeabilities incerased as the contents of PEG400 increased. For the ideal selectivity, there is no big difference in values of between PEBAX 3533 and PEBAX/PEG400 membranes. The increase of permeabilities is due to the increases of solubilities of gases in question and this will be explained in more detail.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.715-720
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• 2014

A Cu(II) complex with an three nitrogens and one sulfur coordination environment was synthesized and characterized. Its redox potential was observed at 0.483 V vs. NHE, very similar to that of a Cu-containing fungal enzyme, galactose oxidase, which catalyzes the oxidation of alcohols to corresponding aldehydes with the concomitant reduction of molecular oxygen to water. The Cu(II) complex selectively oxidizes the benzylic alcohols using TEMPO/$O_2$ under mild reaction conditions to corresponding aldehydes without forming any over-oxidation product. Moreover, the catalyst can be recovered and reused multiple times for further oxidation reactions, thus minimizing the waste generation.

• Journal of Biosystems Engineering
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• v.40 no.4
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• pp.373-393
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• 2015

Background: Cellulose is a ubiquitous, renewable and environmentally friendly biopolymer, which has high promise to fulfil the rising demand for sustainable and biocompatible materials. Particularly, the recent progress in the synthesis of highly crystalline cellulose-based nanoscale biomaterials, namely cellulose nanocrystals (CNCs), draws significant attention from many research communities, ranging from bioresource engineering, to materials science and engineering, to biological and biomedical engineering to bionanotechnology. The feasibility of harnessing CNCs' unique biophysicochemical properties has inspired their basic and applied research, offering much promise for new biomaterials with diverse advanced functionalities. Purpose: This review focuses on vital issues and topics on the recent advances in CNC-based biomaterials with potential, in particular, for bionanotechnology and biological and biomedical engineering. The challenges and limitations of CNC technology are discussed as well as potential strategies to overcome them, providing an essential source of information in the exploration of possible and futuristic applications of the CNC-based functional "green" nanomaterials. Conclusion: CNCs offer exciting possibilities for advanced "green" nanomaterials, driving innovative research and development in a wide range of fields, including biological and biomedical engineering.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.26.2-26.2
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• 2007

• Analytical Science and Technology
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• v.19 no.1
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• pp.39-44
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• 2006

Puh-erh tea was extracted with water and then fractionated sequentially with n-hexane, ethyl acetate, n-butanol to find antioxidative compounds. The fractions were examined on the antioxidant activity using two different methods, free radical scavenging activity measurement and reductive potential. Those antioxidant activities were compared to standard antioxidants such as butylated hydroxyanisole(BHA), butylated hydroxytoluene (BHT), and ${\alpha}$-tocopherol. EA fraction of Pu-erh tea was showed excellent antioxidative activities over BHA and BHT.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1449-1450
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• 2004

• Korean Journal of Materials Research
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• v.23 no.12
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• pp.745-756
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• 2013

Recent rapid development of the Chinese economy based on science and technology is challenging Korean industries and economy. Since the driving force for this rapid development of China is known to be scientific technologies, the purpose of this research is to confirm the current status of Chinese scientific research in the field of "Materials Science and Engineering" and propose a strategy for competition with China. Even though there are numerous journals of "Materials Science and Engineering", the 10 most popular journals with high impact factors were selected to cover general materials, nano materials, bio materials, and electronic materials. It was found that the number of scientific papers written by Chinese scientists for the materials field in the 10 journals was slowly increasing from the year 2000 until 2005, but has been rapidly increasing since 2005. This research found that Chinese research activities in the traditional metallic materials and nano materials have tremendously increased to occupy around 30 % or more papers published in several major journals related with materials science and engineering. On the other hand, bio materials and electronic materials research has not been pursued so actively; however, very recently the number of publications in these fields is also beginning to increase. To compete with this tremendously growing Chinese scientific development, Korea should have a policy of "selection and concentration" in materials-related fields, including basic science in nano, bio, and electronic materials.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.553-556
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• 2009

We investigated an application of supramolecular protein, and demonstrated the metal induced lateral crystallization utilizing ferritins with Ni nanoparticles, named the "bio-nano-crystallization". So far, this method has required long time, because of this method condition based on the conventional solid phase crystallization. In this study, we applied the pulsed rapid thermal annealing to bio-nanocrystallization. As a result, we succeeded in the crystallization for a short time. We found that the TFTs characteristics were improved with decrease metal impieties in poly-Si thin films by this method.