• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.603-608
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• 2018

Although the voltage-applied discharge method is most widely used in the semiconductor and display industries, periodic management costs are incurred because the method causes defects due to the absorption of ambient fine dust and causes emitter tip contamination due to the discharge. The emitter tip contamination problem is caused by the accumulation of fine particles in ambient air due to the corona discharge of the ionizer. Fuzzy ball generation accelerates the wear of the emitter tip and deteriorates the performance of the ionizer. Although a mechanical cleaning method using a manual brush or an automatic brush is effective for contaminant removal, it requires management of additional mechanical parts by the user. In some cases, contaminants accumulated in the emitter may be transferred to the wafer or product. In order to solve this problem, we developed an ionizer for a clean environment that can remove the pencil-type emitter tip and directly ionize the surrounding gas molecules using the tungsten wire located inside the ion tank. As a result of testing and certification by the Korea Institute of Machinery and Materials, the average concentration was $0.7572particles/ft^3$, the decay time was less than two seconds, and the ion valance was 7.6 V, which is satisfactory.

• Current Research on Agriculture and Life Sciences
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• v.12
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• pp.83-95
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• 1994

Fixation rate of reactive dyes on silk fibroin showed the same tendency to absorption rate. Fixation rate of Yellow 179 and Blue 71 was quite slow and Black 5, Blue 49, Blue 4, Blue 19 and Blue 21 was relatively fast. Weight increase by MAA graft polymerization onto filk fibroin was decreased, on the whole, according to the the increase of dye fixation, but weight increase of silk fibroin dyed with Blue 71 and Blue 21 was much higher than that of silk fibroin. And weight increase of silk fibroin dyed with Yellow 179 was similar to that of silk fibroin and in case of Blue 19, weight increase was about 12%, constantly. Weight increase of silk fibroin dyed with Blue 71 and Blue 21 was higher and the others were lower than of silk fibroin. And weight increase was diminished according as the dyeing temperature rises. The color was a little changed by MAA graft polymerization.

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.153-160
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• 2011

In this study, we have developed taste and other functional enhancements of yam chips, from tasteless and flavorless yam slices, through the process of soaking freeze-dried yam in different commercially available juices, including apple, omija (fruit of Maximowiczia typica), grape, wild grape, orange, tomato, red ginseng, and black garlic juice. The analyses of color (brightness, redness and yellowness), pH, brix, acidity, total polyphenol, total flavonoids, total sugar and reducing sugar, DPPH and ABTS scavenging activity, reducing power and nitrite scavenging activity, of the different yam chips showed that the freeze-dried yam slices absorb various components of fruit juices, such as flavonoids, sugars, organic acids and flavors, during the soaking process. These changes resulted in increased taste (both sweet and sour tastes), flavor and antioxidant activity in the yam chips. The soaking time for yam slices in juice is considered to be a crucial factor for the taste and bioactivity of yam chips. In the case of grape juice-yam chips, which had the highest preference among the 8 different chips, the optimum soaking time was noted as 120 seconds. The optimization of the soaking process is necessary for various juices. These results suggest that taste, and other functional enhancements, in yam chips can be developed by juice-soaking and freeze-drying methods.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.824-830
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• 2015

The influence of phosphorous precursors, $NH_4H_2PO_4$, $(NH_4)_2HPO_4$, $H_3PO_4$, $(C_2H_5)_3PO_4$, and $P_2O_5$, on the catalytic performance of the $BiFe_{0.65}MoP_{0.1}$ catalysts in the oxidative dehydrogenation of 1-butene to 1,3-butadiene was studied. The catalysts were characterized by XRD, $N_2$-sorption, ICP, SEM and TPRO analyses. It was not observed big difference on the physical properties of catalysts in accordance with used different phosphorous precursors, however, the catalytic performance was largely depended on the nature of the phosphorous precursors. Of various precursors, the $BiFe_{0.65}MoP_{0.1}$ oxide catalyst, which was prepared from a phosphoric acid precursor, showed the best catalytic performance. Conversion and yield to butadiene of the catalyst showed 79.5% and 67.7%, respectively, after 14 h on stream. The cation of phosphorous precursors was speculated to affect the lattice structure of the catalysts during catalyst preparation and this difference was influenced on the re-oxidation ability of the catalysts. Based on the results of TPRO, it was proposed that the catalytic performance could be correlated with re-oxidation ability of the catalysts.

• Food Science and Preservation
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• v.19 no.1
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• pp.144-152
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• 2012

The temperature changes and quality characteristics of $Makgeolli$ produced using rice treated with $Gaeryang-Nuruk$ (commercial improved $Nuruk$) extract were investigated. During fermentation, the treated rice maintained a lower temperature than the control and then rose after the fifth mashing day. For all the treatments, the numbers of yeast, LAB and AAB colonies increased on the second mashing day, and then gradually decreased. As the fermentation proceeded, the pH gradually increased from the third mashing day, and eventually became higher than that on the initial mashing day. The total acid contents increased on the first mashing day, but as the fermentation progressed, they showed little change. The amino acidity and soluble solid contents during overall fermentation and reducing-sugar contents was reduced until the first mashing day, and increased from the day after. As for the alcohol content, that of the control was 6.87% on the first mashing day, and then gradually increased, nuruk-extract-treated rice began with 9~10% alcohol content and then increased as the fermentation proceeded. Among the organic acid contents, lactate was the main material. In the sensory evaluation, the 24 h-, 48 h- and 72 h- treated rice samples showed somewhat good response.

• Membrane Journal
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• v.27 no.4
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• pp.328-335
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• 2017

Fabricating photocatalytic composite membrane with a mesoporous and tailored morphological structure would have significant implication for environmental remediation. In this study, we reported hybrid $TiO_2$ immobilized photocatalytic membrane and its application for the treatment of dye solution. Photocatalytic film with high porosity and homogeneity was fabricated by graft copolymer as polymer template. Hybridization of membrane filtration with photocatalysis was successfully achieved by photocatalytic membrane reactor developed. Result showed that membrane permeability was significantly reduced after immobilizing the $TiO_2$ film on bare $Al_2O_3$ support. The membrane characterization indicated that well organized $TiO_2$ film was successfully formed on $Al_2O_3$ support. Benefiting from the controlled morphology of $TiO_2$ film, the composite membrane exhibited almost complete degradation of organic dye within 5 h of filtration under UV illumination. Langmuir-Hinshelwood model explained degradation of organic dye. First-order rate constant was approximately six times with $TiO_2$ immobilized composite ceramic membrane, higher than the one with the bare $Al_2O_3$ support (0.0081 vs. $0.0013min^{-1}$).

• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.263-270
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• 2009

Carbon felt surface was modified by heat or acid treatment in order to use for the electrode of a redox-flow battery. Polymers on the surface of carbon felt was removed and oxygen-containing functional group was attached after the thermal treatment of carbon felt. Thermal treatment was better for the stability of the carbon structure than the acid treatment. Oxygen-containing functional group on the thermally treated carbon felt at 500$^{\circ}C$ was confirmed by XPS and elementary analysis. BET surface area was increased from nearly zero to 96 $m^2/g$. Thermally treated carbon felt at 500$^{\circ}C$ showed lower activation polarization than the thermally treated carbon felt at 400$^{\circ}C$ and the acid-treated carbon felt in the cyclicvoltammetry and polarization experiments. The thermally treated carbon felts at 400$^{\circ}C$ and 500$^{\circ}C$ and the acid-treated carbon felt was applied for the electrode to prepare vanadium redox flow battery. Voltage efficiencies of charge/discharge were 86.6%, 89.6%, and 96.9% for the thermally treated carbon felts at 400$^{\circ}C$ and 500$^{\circ}C$ and the acid-treated carbon felt, respectively.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.10-24
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• 2013

The state-of-arts of multiscale simulation (MSS) in science and engineering is briefly presented and MSS for process development (PD-MSS) is proposed to effectively apply the MSS to the process development. The four-level PD-MSS is composed of PLS (process-level simulation), FLS (fluid-level simulation), mFLS (microfluid-level simulation) and MLS (molecular-level simulation). Characteristics and methods of each level, as well as connectivity between the four levels are described. For example in PD-MSS, absorption column, fluidized-bed reactor, and adsorption process are introduced. For successful MSS, it is necessary to understand the multiscale nature in chemical engineering problems, to develop models representing physical phenomena at each scale and between scales, to develop softwares implementing mathematical models on computer, and to have strong computing facilities. MSS should be performed within acceptable accuracy of simulation results, available computation capacity, and reasonable efficiency of calculation. Macroscopic and microscopic scale simulations have been developed relatively well but mesoscale simulation shows a bottleneck in MSS. Therefore, advances on mesoscale models and simulation tools are required to accurately and reliably predict physical phenomena. PD-MSS will find its way into a sustainable technology being able to shorten the duration and to reduce the cost for process development.

• Journal of Life Science
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• v.14 no.5
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• pp.874-881
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• 2004

Angiogenesis has been implicated in progression of inflammation, arthritis, psoriasis, atherosclerosis as well as tumor growth and metastasis. Intensive studies have been carried out to develop a strategy for cancer treatment by blocking angiogenesis. During angiogenesis, endothelial proliferation and migration essentially occurs upon activation. In this study, we compared the expression profiles of human umbilical endothelial cells activated by incubating in vitro in the rich medium containing several growth factors, and non-activated ones. cDNA targets derived from total RNAs of HUVEC activated for 13 h in M199 medium containing endothelial cell growth supplement, 20% fetal bovine serum, and heparin, after reaching 70～80% confluency, or non-activated, were hybridized onto oligonucleotide microarrays containing 1,8864 genetic elements. Unsupervised hierarchical clustering analysis resulted in two subgroups on dendrogram exhibiting activated and non-activated HUVECs. We then extracted 122 outlier genes which were shown to be up-regulated or under-expressed by at least 2-folds in activated HUVECs. Among these, 32 annotated genes were up-regulated and 38 were down-regulated in activated HUVECs. Interestingly, genes involved in cell proliferation, motility, and inflammation/ immune response were up-regulated in activated HUVEC, whereas genes for cell adhesion or vessel morphogenesis/function were down-regulated. Unexpectedly, the expression of genes well-characterized as angiogenesis markers was not changed except Eph-B4, which was down-regulated about 4 folds. 52 unknown genes were also up- or down-regulated. Therefore, these results could provide an opportunity to targeting new vascular molecules for the development of anti-angiogenic molecules.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.406-417
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• 2012

In this study, eco-friendly hybrid composite boards were manufactured from green tea, three kinds of charcoals and wood fiber for developing interior materials to reinforce the functionalities such as the deodorization and the absorbability on the green tea-wood fiber hybrid boards in the previous researches. The effects of kind of raw materials and the component ratio of raw materials on dimensional stability, deodorization and emission of formaldehyde were investigated. Thickness swelling of the hybrid composite boards increased with increasing of component ratio of green tea and charcoals, but the values were markedly lower than that of Korean standard (KS) for commercial medium density fiber board (MDF), except for hybrid composite boards composed of greed tea, activated charcoal and wood fiber. Reduction rate of ammonia gas for the hybrid composite boards composed of green tea, activated charcoal and wood fiber showed a high value of 96% after 30 minute from the beginning of the test, and the other hybrid boards also showed a high value of about 95% after one hour. Emission amount of formaldehyde was similar to that of $E_0$ grade in case of using $E_1$ grade urea resin, and was similar to that of super $E_0$ grade in case of using $E_0$ grade urea resin.