• Journal of the Korean Society for Precision Engineering
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• v.31 no.5
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• pp.451-457
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• 2014

Surface roughness of mechanical components is an important factor which affects the tribological phenomena. Various surface patterns have been applied to surfaces to improve the tribological characteristics of mechanical components. In this work, the friction reduction effect of micropatterns on silicon was investigated. For this purpose, micro-dimple patterns were fabricated on silicon wafer by DRIE process. In the friction experiments silicone oil was used as lubricant. Also, the lubricant was cleaned to simulate a lubricant depleted condition. In depleted lubricated condition, friction coefficient of micro-pattern specimens was lower than specimens without micro-patterns. It was found that friction reduction effect of micro-pattern could be successfully maintained even after cleaning the lubricant on the surface.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.8-11
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• 2007

The new technologies in mobile display developed in SEC are briefly reviewed. For a differentiation, SEC's LTPS line is based on SLS (Sequential Lateral Solidification) technology. In this paper, the characteristics of SEC's SLS in recent and future mobile displays were discussed. The microstructure produced by SLS crystallization is dependent on SLS process conditions such as mask design, laser energy density, and pulse duration time. The microstructure and TFT (Thin Film Transistor) performance are closely related. For an optimization of TFT performance, SLS process condition should be adjusted. Other fabrication processes except crystallization such as blocking layer, gate insulator deposition and cleaning also affect TFT performance. Optimized process condition and tailoring mask design can make it possible to produce high quality AMOLED devices. The TFT non-uniformity caused by laser energy density fluctuation could be successfully diminished by mixing technology.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.51-52
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• 2006

Our company(KOWACO) has periodically performed off-line diagnostic test for 14 hydro generators (rated 11 kV over) for 15 years. In this paper, we summarized results of dissipation factor tip-up test and partial discharge test about these generators. Among these, we chose two generators and performed insulation reinforcement (cleaning and varnish painting). We compared change of insulation condition for the stator winding based upon off-line diagnostic test result before and after repair. Test result shows that insulation condition was improved after insulation reinforcement. This insulation reinforcement has a function to reduce cause of deterioration, so we can know that it extends lifetime of generator and it is a very important factor for stable operation of facilities.

• Journal of Conservation Science
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• v.30 no.2
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• pp.123-136
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• 2014

Considering that decision in conservation treatment for damaged objects should consider not only various options of methodology of intervention but also possible consequences of different types of intervention, it is a difficult task to decide and propose clear and safest solution of preserving an object. In addition, it should be constantly challenged by conservators even if it is proved technique or methodology in a past treatment. Therefore, there is no absolute solution which can be applied to all practice but each decision can be different case by case. It is not possible to estimate the way how the present condition of material and environmental aspects would affect to the condition of an object in future. However if conservators keep trying to set out various ways of analysing pro and against effect of past treatments, it would be able to provide useful logics of proving efficiency and appropriateness of a certain treatment. Understanding that the advantage of laser technique is to adopt a way of cleaning an object without making a direct contact, which is different from other techniques, this paper aims at securing stability of laser techniques, although it remains a limitation in the compatibility to all other materials. This study has examined reacting process on the painted pigments against laser beam by using CLSM in order for it to display both the problems from such reacting process and the efficiency of it as a cleaning methodology. It has intended to estimate the result of laser techniques and propose the range of applicability.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.9
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• pp.624-629
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• 2013

The relation between performance maintenance conditions and those cost efficiency was studied to choose an optimum operating condition in the seawater desalination pretreatment system. A hollow fiber microfiltration module, which was developed with domestic technology, was tested with the various operating conditions such as chemically enhanced backwash cycles and design dosages of a cleaning chemical. Transmembrane pressure was measured to investigate membrane fouling status and cleaning degree. In addition, economic analysis was performed to compare water production costs by the operation condition. As a result, The operation mode III, chemically enhanced backwash at once a day with 100 mg/L of sodium hypochlorite (NaOCl) was selected. The concurrent evaluation between membrane filtration performance and its economic analysis will be suitable to choose an efficient optimum condition.

• Textile Coloration and Finishing
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• v.32 no.2
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• pp.89-95
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• 2020

In this study, the efficacy of Amaranth(Amaranthus spp. L.) as a natural dye resource was investigated for wool fabrics. It is known that a large amount of flavonoid and anthocyanin colorant are contained in leaves and stems, as well as red flowers. The optimum condition of dyeing was 1.3% of dye concentration(o.w.b.) at 100℃ for 60 minutes, resulting the K/S value, 23.43 and R Munsell color on the wool fabrics. Al, Fe, Zinc and Titanium were used as a mordant. The mordant improved the dye uptake, regardless of the mordant type and mordant method. The pre-mordanting method was more effective than the post-mordanting method. Al pre-mordanted fabric showed the highest K/S, 30.02. Light fastness and washing fastness were high in grades 4-5 and 5, and rubbing fastness was good in grades 4 and 4-5 in dry condition, but low in grades 2-3 and 3 in wet condition. The dry cleaning fastness was excellent in all 5 grades. However, the alkaline perspiration fastness ratings were low in grades 2-3 and 3. The results show Amaranthus spp. L. colorant can be used as a functional natural dye for wool fabrics.

• Biomolecules & Therapeutics
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• v.15 no.4
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• pp.224-229
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• 2007

Depurination, the release of purine bases from nucleosides by hydrolysis of the N-glycosidic bond, gives rise to alterations of the cell genome. Although, cells have evolved mechanisms to repair these lesions, unrepaired apurinic sites have been shown to have two biological consequences: lethality and base substitution errors. 2-Bromopropane (2-BP) is used as an intermediate in the synthesis of pharmaceuticals, dyes, and other organics. In addition, 2-BP has been used as a cleaning solvent in electronics industry. But, 2-BP was found to cause reproductive and hematopoietic disorders in local workers exposed to it. We observed massive depurination after incubation of 2'-deoxyadenosine (dA) and 2'-deoxyguanosine (dG) with the excess amount 2-BP at the physiological condition (pH 7.4, $37^{\circ}C$), which were analyzed by HPLC and LC-MS/MS. In addition, time and dose response relationship of depurination in dA and dG induced by 2-BP at the physiological condition were investigated.

• Membrane Journal
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• v.24 no.3
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• pp.201-212
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• 2014

This study was performed to discover the optimum operation conditions for the advanced water treatment using the ceramic membrane, introduced the first in the nation at the Y water treatment plant (WTP). The result of investigation to find the optimum operation conditions which can continue preserving the filtration performance as well as satisfying both the economics and the water quality is as follows. In the ordinary water quality condition of the Y WTP, the optimum filtration time(the backwash period), which can minimize the production of backwash waste and preserve the membrane performance was examined to be 4.0 hours on basis of institution capacity ($16,000m^3/day$). Examining the recovery rate of TMP from the chemical cleaning (CIP) discovered that the inorganic contaminants, which cause membrane fouling, such as iron, manganese, aluminum, were removed through the acidic cleaning using citric acid, whereas the membrane recovery rate was found to be low. But, on the other hand, the TMP was recovered to the initial value from the alkali cleaning using the NaOCl. Therefore, the main contaminant causing the fouling was determined to be hydrophilic organic compound( biopolymer). The membrane recovery rate is highly influenced by the temperature of the cleaning chemical. That is, the rate increased with increasing temperature.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.356-364
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• 2020

An experimental study to investigate the effect of self-cleaning of mortar mixed with photocatalyst was performed out in this study. Test parameters included the photocatalyst content and surface roughness of the specimens. The experimental mortar specimens were manufactured by mixing a photocatalyst by cement weight of 2.5%, 5.0%, 7.5% and 10.0%. In addition, the surface roughness was categorized into three cases. They included flat surface condition, little surface roughness(medium roughness), and high surface roughness. After mortar specimens were cured for 28 days, they were illuminated by an ultraviolet lamp for 24 hours and immersed in a methylene blue conditioning solution for 12 hours. Thereafter, an ultraviolet(UV) lamp was illuminated on the specimens for 48 hours in an experimental chamber and then the color change of methylene blue solution was measured by using a spectrophotometer over illuminating time of UV lamp. The color change of methylene blue tended to increase as photocatalyst contents increased. Test results meant that photocatalyst was effective for self-cleaning in mortar. However, the color change of the methylene blue solution did not show a noticeable tendency at different surface roughness conditions. It might be due to the uneven photocatalyst distribution on the surface of mortar specimens.

• Journal of the Korean Society of Costume
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• v.39
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• pp.79-89
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• 1998

This study was carried out the effect of stability and color extract for it's condition in the curcuma L.. dyeing. The stability is to investigate the absorbance of the curcumin, one of the major yellow pigments and the stability regarding the effect of light, oxygen temperature and pH. The dyeing condition is compared the effect of mordanting condition and the best way to extract pigment and analysed through the color-fastness rating, color-difference value test. The main results obtained are summarized as follows ; 1.The best and proper solvent to extrect curcumin pigment was a ethanol and a distilled water. 2. The light effect indicated that the absorbances of solution in absence of ligh was more stable. 3. The oxygen(O2) effect to curcumin show-ed that the condition in the absence of O2 was more stable than that in presence of O2 4. The temperature showed that the absorbnace was best stable in4$^{\circ}C$ and less changed at $25^{\circ}C$ 5. The curcumin-etanol solution was stable in pH 2~4. 6. Generally color-fastness rating to silk, wool and cotton indicated that crocking C.F. and perspiration C.F. were more than 3rd grade and dry cleaning C.F. was more than 4th grade. But light color-fastness and washing color-fastness were very poor. 7. To make good color fastness, the mordan-ting treated group and the pre-mordant conditions were more effective than others 8. When compared with color-difference value test indicated that the silk was looks like more reddish and bluish color and than the wool and cotton were greenish and bluish. As a mordant, A(C2H4OH(COOH3) and D(K2Cr2O7)were more effective to make green-ish color in the silk and the reddish color was abtained by B(Al.K(SO4)2.12H2O) and C(FeSO4.7H2O).