• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2364-2367
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• 1999

Polymer insulating materials are widely used in power distribution and transmission systems for their good dielectric properties, light weight, low cost, and good contamination performance. Tracking is one of the biggest problems to be overcome in polymer insulating materials. The alumina trihydrate(ATH) is widely used as a filler for improve the tracking performance of silicone rubber. In this paper, we have investigated the influence of surface treatment of fillers on the tracking performance of silicone insulator using the IEC 587 tracking test method.

• Journal of the Korea Safety Management & Science
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• v.1 no.1
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• pp.183-195
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• 1999

Most of chemical plant are using toxic and dangerous materials, inflammable and poisonous. There are many accidental dangers by escaping of fire, explosive and poisonous materials in case of high temperature and pressure. The accidents lead to taking employer's and local people's life and environmental contamination. Therefore, 27 small-medium chemical plant, which size is 30 ∼ 200 employees out of safety management agent ill the area of A was selected in this study. The problems of safety management and several countermeasures at the chemical plants was indicated through the analyzed data. Prior to this analysis, top managers' concerns, equipment maintenance for the safety management are needed. For the future, calamity prevention countermeasures by industrial disaster analysis are needed and active safety management programs are investigated for the industrial disaster prevention and productivity enhancement at the chemical plant.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1504-1507
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• 2009

In this paper, the etching behavior of ZnO in $CF_4$ plasma mixed Ar was investigated. Previously, the etch rate in $CF_4$/Ar plasma was reported that it is slower than that in Cl containing plasma. But, plasma included Cl atom can produce the by-product such as $ZnCl_2$. In order to solve this film contamination, no Cl containing etching gas is required. We controlled the etching parameter such as source power, substrate bias power, and $CF_4$/Ar gas ratio to acquire the fast etch rate using a ICP etcher. We accomplished the etching rate of 144.85 nm/min with the substrate bias power of 200W. As the energetic fluorine atoms were bonded with Zinc atoms, the fluoride zinc crystal ($ZnF_2$) was observed by X-ray photoelectron spectroscopy (XPS).

• Proceedings of the Safety Management and Science Conference
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• 1999.11a
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• pp.97-108
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• 1999

Most of chemical plant are using toxic and dangerous materials, inflammable and poisonous. There are many accidental dangers by escaping of fire, explosive and poisonous materials in case of high temperature and pressure. The accidents lead to taking employer's and local people's life and environmental contamination. Therefore, 27 small-medium chemical plant, which size is 30∼200 employees out of safety management agent in the area of A was selected in this study. The problems of safety management and several countermeasures at the chemical plants was indicated through the analyzed data. Prior to this analysis, top managers' concerns, equipment maintenance for the safety management are needed. For the future, calamity prevention countermeasures by industrial disaster analysis are needed and active safety management programs are investigated for the industrial disaster prevention and productivity enhancement at the chemical plant.

• 보존과학연구
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• s.28
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• pp.169-182
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• 2007

It is very difficult to attain stable and satisfactory result satisfaction from newly developed materials and methodologies for conservation of cultural properties. In order for an effective conservation method, it is necessary that the manual for application of the proper materials and its methodology should be set up. However, stone conservation value must be established in advance of the manual, because the philosophical concepts and the technical methodology are not standardized. In this study, therefore, the conservators' opinion about the conservation for stone artifacts was collected. The opinions were based on the questionnaire about cleaning of surface contamination on masonry, and hereafter those will be referred to the conservation method about stone artifacts.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1292-1295
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• 2004

본 연구는 Cu CMP공정 중 알루미나 연마입자의 wafer 표면에서의 점착과 오염을 AFM (Atomic Force Microscopy)을 사용하여 슬러리내에서 점착력 측정과 실제 연마 후 wafer 표면의 오염을 실험적으로 비교 평가하였다. 연마입자의 adhesionn force 측정에 있어서도 역시 wafer들의 zetapotential 결과와 잘 일치하였으며, 모든 wafer 종류에 관계없이, 산성 영역에서 염기성영역의 슬러리가 적용됨에 따라 adhesion force가 작아짐을 확인할 수 있었다. 특히 FSG wafer의 zetapotential 결과는 비록 산성 분위기에서는 양성 전하값을 나타내었으나, 염기성 분위기의 pH에서는 급격하게 음성 전하값을 나타내었고, 이는 adhesionn force결과와 FESEM 결과와 잘 일치하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.427-430
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• 2008

Electroforming is one of the key technologies for the regenerative thrust chamber of the rocket engine. To use nickel electroforming method for the thrust chamber, direct electroforming of nickel on cupper and the welding method between different materials are needed. Minimizing the internal stress is one of the important factor for making thick electroforming,. Also minimizing contamination(ex. Sulfur containing compound) is another important factor for the stability of quality. This paper includes advanced methods for thick nickel electroforming, those of strength test results and EDS/EPMA inspection results. Advanced for electroforming process makes the achievement of Electro-beam welding between Inconel718(Manifold) and Nickel Electroforming. This paper also includes the influence of the electroforming precipitation angle on strength. Thus advanced electroforming improvement processes and the test results make achievement for manufacturing of the regenerative thrust chamber with direct nickel thick electroforming on cupper materials.

• Microbiology and Biotechnology Letters
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• v.36 no.3
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• pp.173-181
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• 2008

Bovine blood, cell, tissue, and organ are used as raw materials for manufacturing biologics such as biopharmaceuticals, tissue-engineered products, and cell therapy. Manufacturing processes for the biologics have the risk of viral contamination. Therefore viral validation is essential in ensuring the safety of the products. Bovine parvovirus (BPV) is one of the common bovine pathogens and has widely been known as a possible contaminant of biologics. In order to establish the validation system for the BPV safety of biologics, a real-time PCR method was developed for quantitative detection of BPV contamination in raw materials, manufacturing processes, and final products. Specific primers for amplification of BPV DNA were selected, and BPV DNA was quantified by use of SYBR Green 1. The sensitivity of the assay was calculated to be $1.3{\times}10^{-1}\;TCID_{50}/mL$. The real-time PCR method was validated to be reproducible and very specific to BPV. The established real-time PCR assay was successfully applied to the validation of Chinese hamster ovary (CHO) cell artificially infected with BPV. BPV DNA could be quantified in CHO cell as well as culture supernatant. Also the real-time PCR assay could detect $1.3{\times}10^0\;TCID_{50}/mL$ of BPV artificially contaminated in bovine collagen. The overall results indicated that this rapid, specific, sensitive, and robust assay can be reliably used for quantitative detection of BPV contamination during manufacture of biologics.

• Journal of Radiation Protection and Research
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• v.28 no.4
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• pp.299-309
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• 2003

In an accidental release of radioactive materials to the environment the contaminative influence of animal products due to the inhalation of air and the ingestion of soil of livestock, both of which are dealt with as minor contaminative pathways in most radioecological models but may not be neglected, was investigated with the improvement of the Korean dynamic food chain model DYNACON Although mathematical models for both contaminative pathways have been established for considering all animal products and incorporated into the model, investigation was limited to milk. As a result, it was found that both pathways are influential in the contamination of milk in the case of an accidental release during the non-grazing period of dairy cows. In the case of an accidental release during the non-grazing period, the inhalation of air was more influential than the ingestion of soil in the early days following an accidental release. While, it was the opposite with the lapse of time. If precipitation is encountered during an accidental release, contaminative influence due to the ingestion of soil was greater compared with the cases of no precipitation, in general, because of a stealer deposition of radionuclides onto the ground. Precipitation during an accidental release was a less influential factor in $^{131}I$ (elemental iodine) contamination compared with the $^{137}Cs\;and\;^{90}Sr$ contaminations. In the case of an accidental release during the grazing period of dairy cows, the contaminative influence due to the inhalation of air was negligible.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.916-922
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• 2018

Recently, power plant effluent condensers received a Renewable Energy Certificate as components of hydrothermal energy (weighted 1.5 times) as one target item of the Renewable Portfolio Standard (RPS) policy. Accordingly, more attention is being paid to the value of thermal wastewater as a heat source. However, for utilization of thermal wastewater from power plants in high-turbidity areas like the West Sea of Korea, a turbidity reducing system is required to reduce system contamination. In this study, an experimental test was performed over a month on thermal wastewater from power plants located in the West Sea of Korea. It was found that water turbidity was reduced by more than 80 % and that the concentration of organic materials and nutrient salts was partially reduced due to the reduction of floating/drifting materials. To conduct a comparative analysis of the level of contamination of the heat exchanger when thermal wastewater flows in through a turbidity reducing system versus when the condenser effluent flows in directly without passing through the turbidity system, we disassembled and analyzed heat exchangers operated for 30 days. As a result, it was found that the heat exchanger without a turbidity reducing system had a higher level of contamination. Main contaminants (scale) that flowed in to the heat exchanger included minerals such as $SiO_2$, $Na(Si_3Al)O_8$, $CaCO_3$ and NaCl. It was estimated that marine sediment soil flowed in to the heat exchanger because of the high level of turbidity in the water-intake areas.