• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.296-303
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• 2021

The objective of this study is to investigate the applicability of a Cu-supported honeycomb catalyst as a catalyst for decomposition of a low toxic liquid propellant based on ammonium dinitramide (ADN). A mixture of copper, lanthanum, and alumina was supported on the honeycomb support by wash coating to prepare a Cu-La-Al/honeycomb catalyst. We elucidated that the effect of metal loading on the physicochemical properties of Cu-La-Al/honeycomb catalyst and catalytic performance in decomposition of the ADN-based liquid propellant. As the number of wash coatings increased, the amount of active metal Cu was increased to 4.1 wt%. The BET surface area of the Cu-La-Al/honeycomb catalyst was in the range of 3.1~4.1 ㎡/g. The micropores were hardly present in Cu-La-Al/honeycomb catalysts, however, the mesopores and macropores were well developed. The Cu (2.7 wt%)-La-Al/honeycomb catalyst exhibited the highest activity in the decomposition of the ADN-based liquid propellant, which is attributed to the largest surface area, the largest pore volume, and the well-developed mesopores and macropores.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.494-499
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• 2004

Growth in population and urbanization has progressively increased the loadings of pollutants from non-point sources as well as point sources. Therefore, it is necessary to manage both point and non-point sources contaminations for protecting water environment and improving water quality. This study investigated the characteristics of pollutant release over a wide range of rainfall intensities as a requisite to control road runoff that accounts for the largest portion of non-point source contamination in urban areas. Samples of runoff rainwater collected from real road surfaces were analyzed for physicochemical parameters such as pH, suspended solids, and heavy metals. A experimental model road ($30cm{\times}30cm$) was also used to evaluate wash-off properties of pollutants deposited on the surface as functions of time and rainfall intensity. Analysis of runoff samples on rain events showed that the pollutant wash-off patterns for heavy metal and suspended solids were similar. This implies that the particles in rainwater adsorb heavy metals. Experiments using the model road made of impervious asphalt demonstrate a strong first flush phenomenon. At high rainfall intensity, approximately 80% of total pollutants were released within 15 min. The pollutant wash-off rates rapidly increase from 9 mm/hr to 12 mm/hr of rainfall intensity and decrease over 12 mm/hr of rainfall intensity.

• The International Journal of Costume Culture
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• v.7 no.2
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• pp.151-157
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• 2004

This research is to conservate the old hat and restore its shape and place it on a supportive form in a stable protective container. The hat is a homemade construction, utilizing three different machine made laces, and two cotton net fabrics. The exterior, particularly the top crown piece, as well as the lace along the brim's edge has been generally soiled and discolored. Inside the crown, the cotton net has broken threads, and thread loss in several areas. The paper covering the two wires is very weak, and has discolored the lace in the areas of contact. The plastic buckles of the velvet ribbon have also discolored the areas where there is contact. The wash/bleach bath procedure was very effective. Virtually all of the light brown surface discoloration stains were removed. The darker brown spots, particularly concentrated around the two paper covered wires and assumed to be rust, were $90\%$ removed by the treatment. The brown spots apparently were due to the degradation of the paper covering, and not caused by the wire itself. The buckram foundation lost about $50\%$ of its stiffness, but this was not a major concern due to the fact that this hat should remain it its mount, which has been designed to serve for both storage and exhibition purposes.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.421-428
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• 1996

In this study, in order to make up its draw-back in Cu-ZSM-5 catalytic system, some of transition metals or alkaline earth metals were cocation-exchanged in Cu-ZSM-5. Among various cocation-ion-exchanged ZSM-5 catalysts, Mg/Cu-ZSM-5 has been found the most active and durable in NOx reduction even at high oxygen content as well as at the presence of water vapor. The role of Mg in ZSM-5 is supposed to prevent the dealumination of aluminum ions in super-cage even at harsh hydro-thermal conditions, and also it seems to stabilize the Cu ions in the structure. In order to prepare commercially available catalysts, Mg/Cu-ZSM-5 catalysts were wash-coated on the surface of honeycomb type monolith, and tested in terms of catalytic activities. As a result, it was found that the catalyst prepared bt the wash-coating showed satisfactorily high NOx conversion for the practical use in SCR process.

• Journal of the Korean Solar Energy Society
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• v.29 no.6
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• pp.88-93
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• 2009

This study was conducted to improve the power of PV module using a surface cooling system One of the unique characteristics of PV module is power drop as a module surface temperature increases due to the characteristics of crystalline silicon used in a solar cell. To overcome the output power reduction by temperature effect, module surface cooling using water circulation was performed. By cooling effect, module surface temperature drops maximally $20.3^{\circ}C$ predicting more than 10% power enhancement. Maximum deviation of voltage and current between a control and cooled module differed by 5.1 V and O.9A respectively. The maximum power enhancement by cooling system was 12.4% compared with a control module. In addition, cooling system can wash the module surface by water circulation so that extra power up of PV module can be achieved by removing particles on the surface which interfere solar radiation on the cells. Cooling system, besides, can reduce the maintenance cost and prevent accidents as a safety precaution while cleaning works. This system can be applied to the existing photovoltaic power generation facilities without any difficulties as well.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.309-313
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• 2009

This study was conducted to improve the power of PV module using a surface cooling system. One of the unique characteristics of PV module is power drop as a module surface temperature increases due to the characteristics of crystalline silicon used in a solar cell. To overcome the output power reduction by temperature effect, module surface cooling using water circulation was performed. By cooling effect, module surface temperature drops maximally $20.3^{\circ}C$ predicting more than 10% power enhancement. Maximum deviation of voltage and current between a control and cooled module differed by 5.1V and 0.9A respectively. The maximum power enhancement by cooling system was 12.4% compared with a control module. In addition, cooling system can wash the module surface by water circulation so that extra power up of PV module can be achieved by removing particles on the surface which interfere solar radiation on the cells. Cooling system, besides, can reduce the maintenance cost and prevent accidents as a safety precaution while cleaning works. This system can be applied to the existing photovoltaic power generation facilities without any difficulties as well.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.181-182
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• 2006

When a water jet is injected on the body surface, the pressure and shear stress on the surface are important physical parameters in determining the body surface wash out and physical stimulus. We used the force plate in order to measure the surface average pressure for different nozzle types and distances between a nozzle and a plate. We used the nozzles with a hole dimeter of 1.8, 2.9, 3.2mm, and the shower heads with 10 holes (hole diameter, 1mm) and 20 holes (hole diameter, 1mm). The distances between a nozzle and a plate was 10, 20, 30, 40cm. The results showed that the surface forces were not affected by the distances between a nozzle and a plate. Further numerical studies will be performed to predict wall shear stress based on the measured pressure data.

• Journal of Fashion Business
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• v.9 no.2
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• pp.71-83
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• 2005

In this study, we reviewed the color changes accompanying the laundering, wash fastness, and abrasion fastness of chitosan-treated cochineal-dyed fabrics. The treatment methods were classified into two based on the chitosan treatment: (Method 1): fabric specimens were pre-treated with chitosan prior to the dyeing procedure in salt form. (Method 2): the state of chitosan acid salt formation, coated on the yarn surface, was destroyed and neutralized prior to the dyeing process. The changes in the chitosan treatment methods bear more important meaning in view of the durability. In Method 1, it is highly likely for the chitosan to be detached from the surface by water during laundering since the chitosan is coated as acid salt state. In Method 2, the resistance d the chitosan to water was supposed to revive since the chitosan would return to its original state. Differences in the resistance of the chitosan treatrrent, however, according to the Method 1 and Method 2, fell short of our expectations. In Method 2, the wash fastness did not improve as we expected since the bond between the fibers comprising fabric specimens and the chitosan is not high even if the chitosan itself has high resistance to water.

• Food Science of Animal Resources
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• v.24 no.1
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• pp.86-91
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• 2004

The ability of probiotics containing Lactobacillus acidophilus to adhere to the intestinal epithelium may play an important role in colonization of the gastrointestinal tract and preventing enteric pathogen such as enterohemorrhagic E. coli(EHEC O157:H7. In the study, we investigated the adhesion to human intestinal epithelial cells(HT-29) of strains of L. acidophilus(3 from human, 2 from pig, and 1 from calf). All of the tested strains of L. acidophilus were highly observed adhesion ability(from 10$\^$6/ to 10$\^$7/ cfu/mL), compared to L. rhamnosus GG as control. Also, adhered strains of L. acidophilus were significantly preserved in serial wash-out steps. However, no correlation could be observed between cell surface hydrophobicity and adhesion abilities of the tested strains of L. acidophilus. Inhibition of adhesion of EHEC O157:H7 was also examined, a 2 log cycle reduction was observed by all of the tested strains of L. acidophilus. These results suggest that the strains of L. acidophilus with high adhesion ability are resistant to wash-out and adhesion ability inhibition by selected strains of L. acidophilus helps to prevent adhesion of EHEC O157:H7 to intestinal epithelial cells.

• Journal of Technologic Dentistry
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• v.33 no.4
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• pp.339-347
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• 2011

Purpose: This study was investigated the bonding strength of two kinds of Ni-Cr alloy with respect to the condition of surface treatment. Methods: The surface treatment was performed on the two kinds of Ni-Cr alloy (B alloy and R alloy) specimens, which were sandblasted with $50{\mu}m$, $110{\mu}m$, and $250{\mu}m$ aluminium oxide and were treated with opaque application (paste and wash opaque). The roughness on the surfaces of the specimens was observed. The metal-ceramic interfaces were analyzed with EPMA in order to ionic diffusion, and the shear test was performed. Results: The BA250 specimen, which has higher surface roughness, showed the highest bonding strength in B specimens. In R specimens, the bonding strength of RA110 specimen was the highest. Conclusion: B specimen formed a mechanical bond between metal-ceramic interfaces; however, in the case of R specimen, a chemical bond was formed between that interfaces. There was no significant statistical difference between the bonding strengths of two types of specimens (p>0.05).