• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.28.3-28.3
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• 2008

Contamination has the potential for degrading the performance of the optical payload beyond the limits defined by mission requirements, therefore it must be considered a risk to system performance and must be mitigated. To mitigate contamination problem, contamination budget is allocated according to the contamination requirements which is derived from contamination effect analysis. Once the contamination budget is allocated, prediction for on-ground and in-orbit contaminants amounts and cleanliness control is performed. In this article, typical contamination control for observation satellite is described.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.427-430
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• 2002

This paper presents on contamination performance of polymeric outdoor insulator with different contaminant accumulation. The ESDD (equivalent salt deposit density), tracking resistance and clean-fog test were performed to investigate the characteristics of contamination performance on polymeric outdoor insulator. Furthermore, we evaluated together with the porcelain samples for its comparison. It is found that ESDD of polymeric and porcelain insulator depends on the installation position. This surface accumulation of contaminant lead to the loss of surface hydrophobicity, expecially upper shed part of polymeric insulator. In addition, the effect of an artificial contaminant on the tracking resistance by inclined-plane method and leakage suppression ability under clean fog was surveyed. The time of tracking failure did not appear to change significantly with a much contaminant accumulation, while leakage current under clean-fog increased.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.627-634
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• 2016

In this paper, an augmented video generation method to evaluate the performance of lane departure warning system is proposed. In our system, the input is a video which have road scene with general clean lane, and the content of output video is the same but the lane is synthesized with contamination image. In order to synthesize the contamination lane image, two approaches were used. One is example-based image synthesis, and the other is background-based image synthesis. Example-based image synthesis is generated in the assumption of the situation that contamination is applied to the lane, and background-based image synthesis is for the situation that the lane is erased due to aging. In this paper, a new contamination pattern generation method using Gaussian function is also proposed in order to produce contamination with various shape and size. The contamination lane video can be generated by shifting synthesized image as lane movement amount obtained empirically. Our experiment showed that the similarity between the generated contamination lane image and real lane image is over 90 %. Futhermore, we can verify the reliability of the video generated from the proposed method through the analysis of the change of lane recognition rate. In other words, the recognition rate based on the video generated from the proposed method is very similar to that of the real contamination lane video.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.758-760
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• 1998

This paper provides the results of performance investigation of gas insulated switches(G/S) for distribution power system. In order to investigate anti-contamination capability of G/S we carried out electrical tests and material analysis on the body of G/S and it's accessories. Through this experiment we found out the lead cable of G/S had not anti-contamination capability and G/S had insufficient interval between each phase. In order to improve the performance of G/S for heavy contamination area it is indispensable to replace the lead cable to the new cable which has anti-contamination ability.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.20-24
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• 2022

In the process of long-term use of PEMFC (Proton Exchange Membrane Fuel Cells), chemical degradation of membrane electrode assembly (MEA) occurs due to corrosion of stack elements and contamination of supply gas. In this study, we investigated whether chemically degraded MEA can be recovered by acid washing. The performance was measured and compared in a PEMFC cell after contamination with iron ions and washing with an aqueous sulfuric acid solution. The performance was reduced by about 25% by 0.5 ppm iron ion contamination, and 97.1% performance recovery was possible by washing of 0.15 M sulfuric acid. The membrane resistance was increased due to iron ion contamination of the polymer membrane, and the ionic conductivity was restored by washing the iron ions from the membrane while minimizing the loss of the electrode catalyst by washing with a low-concentration sulfuric acid aqueous solution. The possibility of solving the decrease in durability caused by chemical contamination of PEMFC MEA by the acid washing was confirmed.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.4
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• pp.331-337
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• 2017

Proton Exchange Membrane Water Electrolysis (PEMWE) is one of the most popular and widely used methods for hydrogen production. PEMWE contributes to eco-friendly system via its energy storage system application, hence making it environmentally friendly to use. However, its main drawback is contamination of proton exchange membrane during water electrolysis. Existing cation such as magnesium, calcium and the likes are the cause for membrane contamination. As a result, the cation contamination give rise to degradation of performance of electrolysis and the reverse electrolysis is effective method to remove cation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.2
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• pp.114-118
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• 2009

PVA (polyvinyl alcohol) brush cleaning method is a typical cleaning method for semiconductor cleaning process especially post-CMP cleaning. PVA brush contacts with the wafer surface and abrasive particle, generating the contact rotational torque of the brush, which is the removal mechanism. The brush rotational torque can overcome theoretically the adhesion force generated between the abrasive particle and wafer by zeta potential. However, after CMP (chemical mechanical polishing) process, many particles remained on the wafer because the brush was contaminated in previous post-CMP cleaning step. The abrasive particle on the brush redeposits to the wafer. The level of the brush contamination increased according to the cleaning run time. After cleaning the brush, the level of wafer contamination dramatically decreased. Therefore, the brush cleanliness effect on the cleaning performance and it is important for the brush to be maintained clearly.

• Journal of muscle and joint health
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• v.26 no.3
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• pp.241-250
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• 2019

Purpose: This study was conducted to identify influencing factors on the performance of healthcare-associated infection control and microbiological hand contamination among caregivers at a tertiary hospital. Methods: The participants of this study were 59 caregivers woring at a tertiary hospital. Data were collected from July 1 to 30, 2018. Data were analyzed using descriptive statistics, t-test, ANOVA, Scheffé test, Pearson's correlation coefficients and stepwise multiple regression by SPSS 23.0 Win program. Results: Multiple regression analysis revealed that factors influencing performance of healthcare-associated infection control were awareness (β=.63, p<.001) and the experience of infection-related education (β=-3.40, p=.042). Regression equations describing the performance of healthcare-related infection control were found to be appropriate (F=27.29, p<.001) and accounted for 68% of variance. Factors affecting the degree of microbiological hand contamination were work experience (β=-0.28, p=.026) and healthcare-related infection performance (β=-0.28, p=.029). A regression equation describing the microbiological hand contamination was appropriate (F=6.10, p=.004) and accounted for 42% of variance. Conclusion: The findings of this study suggest that it is necessary to increase performance of healthcare-associated infection control by caregivers. Also, educations for preventing healthcare-associated infection and guidelines for increasing compliance with healthcare-associated infection control are recommended to improve performance of healthcare-associated infection control.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.116-122
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• 2010

It is necessary to be careful about contamination control to minimize the accumulation of the contamination material on satellite surface during the I&T phase. In the space environment which characterized by high vacuum, high and very low temperature, contamination material causes satellite to lose its own performance. Especially, contamination material can accumulate on critical surfaces such as lenses, mirrors, and sensors. KARI(Korea Aerospace Research Institute) conducts the clean room to control and minimize the contamination effect. This paper introduces the principle of contamination and the method of measure and analysis for the contamination.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1306-1313
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• 2012

This paper reports the contamination performance of two distribution arresters (new and used ones) tested under three different contaminant conditions - clean fog, ESDD (equivalent salt deposit density) level (A, B, C, and D), and kaolin contamination conditions, and their leakage current, total leakage current, and component of the resistive leakage current were measured in order to diagnose arrester deterioration. The 3rd harmonics was larger than 5th and 7th ones for the arrester under the clean fog, and as the ESDD contamination level was applied, 5th one became relatively larger than 3rd one. Therefore, these results indicated that the resistive leakage current could be used for the diagnosis of the arresters.