• Journal of Korean Biological Nursing Science
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• v.18 no.4
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• pp.288-295
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• 2016

Background: This study was conducted in order to survey the current state of cleaning, disinfection, rinsing, drying, and storage of gastrointestinal endoscopes. Methods: Eighty hospitals were selected through convenient sampling. Self-reported questionnaire was distributed from September 14 to October 10 in 2015. Results: The response rate was 67.5% (54/80). In 88.9% of the hospitals, reprocessing was performed in a cleaning space separated from the laboratory and 88.9% used an enzymatic cleaner. Disinfectants used were ortho-phthalaldehyde in 63.0%, and paracetic acid in 33.3%. Eighty seven percent of the hospitals used test strips in order to test the effective concentration of disinfectant and in 61.1%, drying was done through passing air and over 70% alcohol. Microbial culture for the quality control of gastrointestinal endoscopes was performed in 77.8%. In the comparison of the adequacy of gastrointestinal endoscope reprocessing, it was observed that gastrointestinal endoscopes were reprocessed more adequately in larger and tertiary care hospitals. Conclusion: Gastrointestinal endoscopes were reprocessed in similar manners, but there were differences in the detailed process. It is still necessary to segment reprocessing into stages, to prepare standardized guidelines, and to monitor compliance with the guidelines.

• Tribology and Lubricants
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• v.34 no.6
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• pp.226-234
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• 2018

Copper chemical mechanical planarization (CMP) has become a key process in integrated circuit (IC) technology. The results of copper CMP depend not only on the mechanical abrasion, but also on the slurry chemistry. The slurry used for Cu CMP is known to have greater chemical reactivity than mechanical material removal. The Cu CMP slurry is composed of abrasive particles, an oxidizing agent, a complexing agent, and a corrosion inhibitor. Citric acid can be used as the complexing agent in Cu CMP slurries, and is widely used for post-CMP cleaning. Although many studies have investigated the effect of citric acid on Cu CMP, no studies have yet been conducted on the interfacial friction characteristics and step height reduction in CMP patterns. In this study, the effect of citric acid on the friction characteristics and step height reduction in a copper wafer with varying pattern densities during CMP are investigated. The prepared slurry consists of citric acid ($C_6H_8O_7$), hydrogen peroxide ($H_2O_2$), and colloidal silica. The friction force is found to depend on the concentration of citric acid in the copper CMP slurry. The step heights of the patterns decrease rapidly with decreasing citric acid concentration in the copper CMP slurry. The step height of the copper pattern decreases more slowly in high-density regions than in low-density regions.

• Journal of The Korean Society of Clinical Toxicology
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• v.3 no.1
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• pp.60-62
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• 2005

A previously healthy 57-year-old woman with dyspnea and wheezing presented to the emergency department a few minutes after exposure to unknown gas from mixing bleach (sodium hypochlorite) and cleaning agent (hydrochloric acid) at work place. Initial physical examination revealed severe wheezing on both whole lung fields, but the chest radiograph was normal. Arterial blood gas analysis showed only moderate hypoxemia. The patient was treated with oxygen, $\beta$adrenergic bronchodilators, antihistamines and corticosteroids, after then symptoms were improved. And the patient discharged against medical advice. We report a rare case of reactive airways dysfuntion syndrome from chlorine gas exposure.

• Membrane Journal
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• v.27 no.3
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• pp.232-239
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• 2017

In this study, the regeneration investigation for waste reverse osmosis membrane filters which were discarded after use for the household water purifiers has been carried out. Sodium hydroxide, sodium bisulfate, and ethylenediamine tetra acetic acid(EDTA). as the chemical cleaning agents were used. And they were in-situ cleaned with the micro-bubble generator as well. The best result was obtained when both 0.1% EDTA and micro-bubbles were used for 30 min cleaning. Thus, when the performance of the brand new RO membrane and restorated RO membrane were compared, the flux, 19.9%, the recovery ratio 45% were enhanced while the salt rejection was reduced for NaCl 100 mg/L solution, in other words, it has been recovered to the original brand new RO membrane filter. Also the removal of pollutants on membrane surface was confirmed in a naked eye through the scanning electron microscopy. Finally, this research has provided the possibility of the re-use of the waste RO membrane filters of household water purifier which were reclaimed or incinerated after use.

• Korean Journal of Materials Research
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• v.31 no.1
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• pp.8-15
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• 2021

Transparent, photocatalytic, and self-cleaning TiO2 thin film is developed by TiO2 sol-gel coating on glass and polycarbonate (PC) substrates. Acetyl acetone (AcAc) suppresses the precipitation of TiO2 by forming a yellowish (complex) transparent sol-gel. XPS analysis confirms the presence of Ti2p and O1s in the thin films on glass and PC substrates. The TiO2-sol is prepared by stabilizing titanium (IV) isopropoxide (TTIP) with diethylamine and methyl alcohol. The addition of AcAcsilane coupling solution to the TiO2-sol instantaneously turns to yellowish color owing to the complexing of titanium with AcAc. The AcAc solution substantially improves the photocatalytic property of the TiO2 coating layer in MB solutions. The coated TiO2 film exhibits super hydrophilicity without and with light irradiation. The TiO2 thin film stabilized by adding 8.7 wt% AcAc shows the highest photo-degradation for methylene blue (MB) solution under UV light irradiation. Also, the optimum photocatalytic activity is obtained for the 8.7 wt% AcAc-stabilized TiO2 coating layer calcined at 450 ℃. The thin-films on glass exhibit fast self-cleaning from oleic acid contamination within 45 min of UV-light irradiation. The appropriate curing time at 140 ℃ improves the anti-fogging and thermal stability of the TiO2 film coated on PC substrate. The watermark-free PC substrate is particularly beneficial to combat fogging problems of transparent substrates.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.4
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• pp.429-436
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• 2008

Membrane system has been increasingly considered as a safe and cost-effective water treatment process especially in case of small scale water works. This research is a basis of membrane application in water works through a long period test with obtaining operation skills and evaluation of water quality and cost competitiveness. For the research, the UF membrane system was installed in small water treatment plant that uses river-bed water as raw water. The system was consisted of 2 stage membrane and operated in constant flow mode (Flux: 1.5, 1.0, 0.9, 0.6). In each different flux condition, TMP trends were showed better results at lower flux condition. And through the high flux condition test, it is certified that membrane system could deal with breakdown of one stage. Water quality of permeate was satisfied the water quality standards especially turbidity. To know what mainly causes fouling on membrane, the test by membrane with several cleaning agents and EDX analysis have done in lab. Through the tests, ferrous concentration in raw water, backwashing water and membrane surface etc. was high and it causes fouling inside and outside of membrane. So acid cleaning using organic acid such as oxalic acid is necessary in Chemical in Place (CIP). At the economical aspect the electrical cost of membrane system is higher than that of slow sand filtration but labor cost can be reduced by automation. However, the use of labor should be determined considering effectiveness and stability of operation. Because during the operation, there are several breakdown such as electrical shock by lightning, water drop in summer, etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3597-3601
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• 2013

In this study, a wet cleaning process, P II, using aqua-regia and sulfuric acid mixture with oxidant agent ($K_2S_2O_8$, $P_2O_5$, $KMnO_4$, $H_2O_2$ etc) is proposed to remove the metastable phase of graphite such as graphene and DLC for high quality synthetic diamonds. The process employed the conventional acid cleaning process (P I) as well as P I+P II to remove the graphite related impurities from the 200um-diamond powders synthesized at 7GPa-$1500^{\circ}C$-5minutes. The degree of cleaning after P I and P I+P II has been observed by naked-eye, optical microscopy, micro-Raman spectroscopy, and TGA-DTA. After P I+P II, the color of diamond became more vividly yellow with enhanced saturation with naked eye and optical microscopy analysis. Moreover, the disappearance of diamond-like-carbon (DLC) peak ($1440cm^{-1}$) observed by Raman spectroscopy confirmed the decrease in amount of remaining impurities. TGA-DTA results showed that the graphite impurities first started to dissolve at $770.91^{\circ}C$ after PI process. However, the pyrolysis started at $892.18^{\circ}C$ after P I+P II process because of the dissolution of pure diamonds. This result proved the effective dissolution of the metastable phase of graphite. We expect that the proposed P II process may enhance the quality of diamonds through effective removal of surface impurities.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.957-964
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• 2010

The deactivated catalyzed diesel particulate filter-trap (DPF) was remanufactured by ultrasonic wave treatment with various prepared solutions, followed by active component re-impregnation, and the emission control performance and surface properties of remanufactured DPF were studied at various remanufacturing conditions. The proper ultrasonic wave cleaning time at various prepared solutions and optimal re-impregnation amounts of active component for the best emission control performance of DPF were investigated and its performance tests were also carried out with various temperatures for the conversions of CO, THC (total hydrocarbon) and PM (particulate matter) by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the emission control performance of DPF remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acid/base solutions and active component re-impregnation method was recovered to 95% level of its activity compared to that of the fresh DPF, which was caused by removing the deactivating materials from the surface of the DPF, through the analyses of performance test and their surface characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.

• Journal of the Korean institute of surface engineering
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• v.49 no.6
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• pp.513-520
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• 2016

Many surface protection methods have been developed to apply to constructional steels which have been used under severe corrosive environments. One of these methods, hot dip galvanizing is being widely used to the numerous constructional steels such as a guard rail of high way, various types of structural steel for manufacturing ship and for some other industrial fields etc.. Recently, the cost of zinc is getting higher and higher, thus, it is considered that improvement of hot dip galvanizing process to reduce the cost of production should be developed possibly. In this study, additives such as acid cleaning solution, $NH_4OH$, $Al(OH)_3$ and $H_2O_2$ were added to flux solution, and omission of water washing treatment after acid cleaning was investigated with some types of flux solutions added with some additives mentioned above. The decrement of pH by adding the acid cleaning solution could be controlled due to neutralization reaction with addition of $NH_4OH$. The flux solution added with both $NH_4OH$ and $Al(OH)_3$ exhibited nearly the same color and pH value as those of orignal flux solution with no added, and the sample dipped to the flux solution which was added with additives mentioned above indicated a relatively good corrosion resistance compared to other samples. However, the flux solution added with $NH_4OH$, $Al(OH)_3$ and $H_2O_2$ exhibited a different color, sediment and a bad corrosion resistance. Consequently, it is considered that omission of water washing treatment may be able to perform by adding optimum additives to the original flux solution.

• Journal of Conservation Science
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• v.16 s.16
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• pp.21-26
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• 2004

A lot of waterlogged shrouds and mummies have been found in tombs revered with lime of the Chosun Dynasty(1392-1910) of Korea. Shrouds were heavily polluted with greyish white material. Greyish white material, which adhered to shrouds excavated from tombs(16C and 17C), was submitted to FT-IR qualitative analysis and fatty acid analysis for cleaning. The results of the FT-IR qualitative analysis identified the main ingredient of the greyish white material as calcium salt of fatty acid, including a little of the fatty acids, lipids and proteins. Therefore the greyish white material fumed out adipocere which was formed from the degradation of the lipids in a dead body. From the fatty acid analysis, hydroxy fatty acids(10-Hydroxyhexadecanoic acid and 10-Hydroxyoctadecanoic acid), which were found in adipocere, were detected. The distribution of contents of fatty acids was also rimilar to that of adipocere which have a high proportion of palmitic acid of saturated fatty acid and a low proportion of oleic arid of unsaturated fatty acid. In view of the results of analyses, it was revealed that greyish white material adhered to shrouds was adipocere moved from a mummy.