• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1089-1092
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• 2003

This paper has been studied on wafer cleaning and photoresist striping in semiconductor fabrication processes using ozone solved deionized water. In this work, we have developed high concentration ozone generating system and high contact ratio ozone solving system to get high efficiency DIO$_3$. Through this study, we obtained 11% ozone gas concentration, 99.5% of ozone efficiency and 51% of solubility in deionized water.

• Laser Solutions
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• v.6 no.3
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• pp.29-35
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• 2003

In semiconductor processing, there are two types of particle contaminated onto the wafer, i.e. dry and wet state particles. In order to evaluate the cleaning performance of laser shock wave cleaning method, the removal of 1 m sized alumina particle at different particle conditions from silicon wafer has been carried out by laser-induced shock waves. It was found that the removal efficiency by laser shock cleaning was strongly dependent on the particle condition, i.e. the removal efficiency of dry alumina particle from silicon wafer was around 97％ while the efficiencies of wet alumina particle in DI water and IPA are 35％ and 55％ respectively. From the analysis of adhesion forces between the particle and the silicon substrate, the adhesion force of the wet particle where capillary force is dominant is much larger than that of the dry particle where Van der Waals force is dominant. As a result, it is seen that the particle in wet condition is much more difficult to remove from silicon wafer than the particle in dry condition by using physical cleaning method such as laser shock cleaning.

• Membrane and Water Treatment
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• v.12 no.2
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• pp.65-73
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• 2021

Sponge ball cleaning can generate an abrasion effect, which leads to an attractive increasing in both permeate flux and membrane rejection. The aim of this study was to investigate the influence of the daily sponge ball cleaning (SBC) on the performance of different UF cross-flow membrane modules integrated with a bioreactor. Two 1"-membrane modules and one 1/2"-membrane module were tested. The parameters measured and controlled are temperature, pH, viscosity, particle size, dissolved organic carbon (DOC), total suspended solids (TSS), and permeate flux. The permeate flux could be improved by 60%, for some modules, after 11 days of daily sponge ball cleaning at a transmembrane pressure of 350 kPa and a flow velocity of 4 m/s. Rejection values of all tested modules were improved by 10%. The highest permeate flux of 195 L/㎡.h was achieved using a 1"-membrane module with the aid of its negatively charged membrane material and the daily sponge ball cleaning. In addition, the enhancement in the permeate flux caused by daily sponge ball cleaning improved the energy specific demand for all tested modules. The negatively charged membrane showed the lowest energy specific demand of 1.31 kWh/㎥ in combination with the highest flux, which is a very competitive result.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.10a
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• pp.93-116
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• 1999

MF membrane element was specially designed for water purification and VSA process which can solve the fouling problem. Especially VSA process is developed for the SK Chemicals' asymmetric microfiltration hollow fiber membranes. In case of outside-to-in filtration process, MF membrane element showed the excellent flux stability caused by cleaning ability of VSA process . Simultaneous back-washing with VSA consideratbly enhances cleaning efficiency. From the result the possibility of the replacement of chemical coagulation and sand filtration process with newly developed VSA process was revealed.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.63-66
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• 1999

MF membrane element was specially designed for water purification and VSA process which can solve the fouling problem. Especially VSA process is developed for the SK Chemical's asymmetric microfiltration hollow fiber membranes. In case of outside-to-in filtration process, MF membrane element showed the excellent flux stability caused by cleaning ability of VSA process. Simultaneous back- washing with VSA considerably enhances cleaning efficiency. Form the result, the possibility of the replacement of chemical coagulation and sand filtration process with newly developed VSA process was revealed.

• Membrane Journal
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• v.26 no.5
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• pp.401-406
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• 2016

In this study, we have investigated the removal of the low level radioactive ions of Cs and I in water by the reverse osmosis (RO) process. The two RO modules produced in domestic region and the waste RO module after the cleaning process were selected. Then we compared removal performance of both Cs and I. The experiments are conducted by varying the concentration of feed, the pressure. As a results, it was confirmed that all three modules are higher I decontamination factor than Cs. And particularly, for the cleaned RO module, its decontamination factor of I was 1140. Since the results at low pressure condition were better than that at high pressure conditions, the use of the direct installation of RO modules on the tap water might be possible. In addition, it was confirmed that the waste RO module after cleaning process using EDTA, SBS and NaOH, increased the decontamination performance better than before cleaning, in particular, the recovery ratio after cleaning was 6.3% higher.

• Membrane and Water Treatment
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• v.8 no.2
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• pp.113-123
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• 2017

This study investigated effects of physical and chemical cleaning methods on the initial flux recovery of fouled membrane in membrane distillation process. A laboratory scale direct contact membrane distillation (DCMD) experiment was performed to treat digested livestock wastewater with 3.89 mg/L suspended solids, 874.7 mg/L COD, 543.7 mg/L nitrogen, 15.6 mg/L total phosphorus, and pH of 8.6. A hydrophobic PVDF membrane with an average pore size of $0.22{\mu}m$ and a porosity of 75 % was installed inside a direct contact type membrane distillation module. The temperature difference between feed and permeate side was maintained at $40^{\circ}C$ with the feed and permeate stream velocity of 0.18 m/s. The results showed that the permeate flux decreased from $22.1L{\cdot}m^{-2}{\cdot}hr^{-1}$ to $19.0L{\cdot}m^{-2}{\cdot}hr^{-1}$ after 75 hours of distillation. The fouled membrane was cleaned first by physical flushing and consecutively by chemicals with NaOCl and citric acid. After the physical cleaning the flux was recovered to 92 % as compared with the initial clean water flux of the virgin membrane. Then 94 % of the flux was recovered after cleaning by 2,000 ppm NaOCl for 90 minutes and finally 97 % of flux recovered after 3 % citric acid for 90 minutes. SEM-EDS and FT-IR analysis results presented that the foulants on the membrane surface were removed effectively after each cleaning step. The contact angle measurement showed that the hydrophobicity of the membrane surface was also restored gradually after each cleaning step to reach nearly the same hydrophobicity level as the virgin membrane.

• Journal of Ocean Engineering and Technology
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• v.20 no.2 s.69
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• pp.46-51
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• 2006

Moonpool characteristics of a cleaning skip related with the performance of a skip are experimentally investigated. Resistance performances of the ship and flow patterns in the moonpool are observed, in order to determine the effect of different shaped moonpool. The ways to reduce ship pithing motion caused by force in the moonpool are examined. Experimental results, using a scale model of cleaning ship with moonpool, show that the step arranged in tier under water leads to significant improvements in performance, such us resistance and ship pithing motion. Depending upon the shape of step in the moonpool, the results indicate that the increment of resistance performance may be up to 35%, especially in the case of no step or high step.

• Journal of Korean Biological Nursing Science
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• v.13 no.3
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• pp.204-210
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• 2011

Purpose: The purpose of this study was to provide basic data for the guidelines for cleaning the feeding bags by comparing the level of contamination according to cleaning and disinfection methods when feeding tube of Neurosurgery Intensive Care Unit patients. Methods: This study was a true-experimental study, with 48 cases in total. The feeding bag of 48 patients were randomly assigned to detergent cleaning method or disinfectant decontamination method. The period of the experiment was January to July 2008, and enteral nutrition was given within 30 minutes for 2 hours, 4 times a day at 7AM, noon, 5PM, and 9PM for seven days. Feeding bags were cleaned after each feeding according to the assigned cleaning and disinfection method followed by microbial cultures on 4th and 8th day before the 7AM feeding. Results: After three and seven days of feeding and cleaning, the level of contamination was significantly lower when bags were cleaned with disinfectant than cleaning with detergent and tepid water. Conclusion: In cases where feeding bags are reused, for example, intensive care unit and home care settings, study findings indicate that cleaning bags with disinfectant is an effective way to prevent contamination of bags.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.2
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• pp.169-175
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• 2017

This study applied microbubbles to reduce membrane fouling in wastewater reuse membrane processes, evaluated and compared the transmembrane pressure with or without the application of microbubbles and the cleaning efficiency with the application of aeration and microbubbles. In addition, this study analyzed foulants removed from the membrane surface. Changes in the transmembrane pressure of membranes with the presence or absence of microbubbles were observed. As a result, transmembrane pressure (TMP) increasing rate decreased twofold when applying microbubbles to realize stable operations. This study compared and evaluated cleaning efficiency applying aeration and microbubbles. As a result, the cleaning efficiency was 5% higher on average when applying microbubbles. In turbidity and total organic carbon (TOC), foulants were discharged when applying microbubbles twice as much as applying aeration. It is thought that particulate foulants precipitated on the membrane surface were more likely to desorb because the adhesion between the membrane surface and particle was weakened by microbubbles. Therefore, it is considered possible to effectively control membrane fouling because of the increase in cleaning efficiency when applying microbubbles to wastewater reuse membrane processes.