• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.3
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• pp.74-82
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• 2001

To reduce the maintenance expense and the possibility of electric outage and/or accident, which causes the decrease in stability and reliability of transmission/distribution line, most of all, accurate measurement for the degree of contamination should be preceded. But the conventional method (brush wiping method), which is recommended in IEC 60815, has sow significant problem in the aspect of man power, expense, error, and so forth. In this investigation, we purpose the development of a new type automatic measuring apparatus, which could measure the degree of contamination on the surface of insulator in outdoor condition. To design and evaluate the apparatus, a FLUX 2D is used, and various laboratory tests, artificial contamination tests, were carried to proof the actual performance. With the result of these effort, we can get the meaningful conclusion to develope a new type automatic apparatus for contamination measurement.

• Journal of Korean Academy of Nursing
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• v.3 no.2
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• pp.45-51
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• 1973

Bacterial cultures of the transfer forceps, 4"$\times$4"mesh gauze and polluted air of nursing units of general surgery, internal medicine, gynecology and pediatrics of S.N.U.H. were carried on for S consecutive days (from 17th to 21s1 August, 1972) to investigate the degree of contamination of such instruments which were used in dressing the patients. 1. The average hospitalized patients for each nursing unit were 24 persons. 2. The frequency of dressing, and using forceps and gauze in surgical nursing unit were 25,316 and 66 times respectively. Actually the forceps were used most frequently. There was no dressing in the nursing unit of internal median. 3. Most of dressing were carried on from 11 : 00 to 13 : 59 o′clock. 4. Averagely 121.5 persons passed through each nursing unit. 549 visitors dropped in the nursing unit of gynecology in maximum, and 219 visitors in the nursing of internal medicine in minimum. The visitors rushed in from 11 : 00 to 13 : 59 o′clock to he 142.5 persons for each nursing unit in average. 5. Colony counts after the bacterial cultures of the forceps and gauze disclosed 1098.44 and 704.51 per plate respectively. 6. The degree of contamination was parallel to the duration and frequency of dressings. 7. The degree of contamination of the instruments was severest in the nursing unit of internal medicine, and !east in the nursing unit of gynecology. On the matter of gauze, the contamination was most extreme in the pediatric nursing unit. 8. There was no significant daily differences in terms of contamination throughout the week. 9. It was disclosed that empty forceps jars were less contaminated than the jars with solution of any kind. 10. Bacterial cultures of the polluted air in corridor showed 73,88 colony counts per plate.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.11
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• pp.86-91
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• 2021

Recently, functional clothes that can reduce deposition and/or penetration of fine dust have been developed. However, there are no methods to quantitatively evaluate the performance of these clothes. In this study, we developed a method to contaminate a fabric using fine dust and established an approach to quantitatively assess the degree of particle contamination on the fabric surface. Silicate powder was chosen as the particle to simulate fine dust because silicate particles are fluorescent under UV light; therefore, they can be distinguished from any color of non-fluorescent fabric surface. A camera with a high-resolution lens system was used to scan the surface of the contaminated fabric surface, and the degree of particle contamination of the fabric surface was analyzed in terms of the pixels corresponding to the area of the fabric surface contaminated by silicate particles. Finished or unfinished nylon fabrics as well as cotton fabrics were contaminated with silicate particles, and their surfaces were scanned using the established camera. The proposed assessment method was found to be useful for quantitatively comparing the degree of particle contamination of the fabrics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.27-30
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• 2002

In this paper, we were investigated leakage current properties of outdoor insulator on climatic environmental factor. Contamination is one of the most important factor to determine the performance of insulator. Thus, it is very important to exam the contamination degree on the outdoor insulator. There are many limits, such as reliability of data, interval of measurement and similarity of environmental conditions, in conventional method. So, we measured phase and leakage current of outdoor insulator using the temperature & humidity chamber. In this investigation, phase difference was measured to compare the variance of phase difference with the contamination degree and relative humidity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.123-127
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• 2002

This paper presented the results of evaluation of artificially contaminated suspension insulators for transmission lines. The suspension insulators were contaminated with kaolin and clay which were included various amount of natural salt. The degree of contamination were evaluated by measuring equivalent salt deposit density(ESDD). Then, the leakage currents were measured as a function of applied voltage, degree of contamination, humidity.

• Journal of Environmental Health Sciences
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• v.1 no.1
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• pp.36-40
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• 1974

A Study on environmental sanitation on the well in Seoul was made to find the degree of Physio-chemical and Bacterial contamination. For this study 30 wells were located at Nokbundong Hongjaidong and Hongeundong from September 13 to 22 1971. As the results of this study the following conclusions were obtained. 1) Seventy per cent were being utilizing by from 10 to 50 households per well. 2) About 93 per cent of the wells were found to be dug out in Rocks. 3) Eighty-three per cent of the wells surveyed in the slums had a depth of water shorter than 20 cm. 4) The degree of Total Viable Bacteria contamination were high point $15{\times}10^2$ low point 13 and coliform bacteria were high point $79{\times}10^1$ low point 1 organism per ml. 5) Only 4 wells (13.3%) were able to drink but 26 wells (86.7%) were not drinking by physio-chemical and Bacterial contamination.

• Water for future
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• v.6 no.2
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• pp.19-29
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• 1973

The progressive contamination of water resulted from man's activity and the use of fertilizers is not restricted only to surface water, but also the shallow groundwater is affected. This type of groundwater contamination is mainly restricted to areas composed of permeable, nonconsolidated sediments forming a shallow aquifer. The chloride and the sulfate resulted from man's activity and the use of fertilizers were measured to study the variations of the groundwater contamination. In general, (1) When water level rises, the rate of groundwater contamination becomes less and when water level declines, the rate of contamination is increased. (2) The highly contaminated season is the early-summer and the less contaminated season is the winter or after rainy season. (3) The groundwater in weathering zone without covering layer. (4) The degree of contamination of wells is increased with the increase of well depth and lowing the water table, because of increasing contaminated water from enlargement of the area of influence of the well.

• Journal of Pharmaceutical Investigation
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• v.3 no.4
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• pp.16-27
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• 1973

An investigation was carried out on a basis of the examination with a view to detecting the degree of microbial contamination for the 82 samples collected from the locally-sold liquid preparations. The results obtained are summarized as follows ; 1. Total viable Bacteria(TVB) per ml. in test sample shows min. 0 and Max. $8.0{\times}10^5$. Among the test samples, 2 items of Herb medicines have shown the highest bacterial contamination degree. 2. The number of unsuitable products are 9(11.0%) of the 82 items tested. Comparing with the study of 1971 (18 or 23.4% of 77 items), this fact suggests that the more than 50% decreasing tendency has come from the technical preventive efforts on bacterial contamination. 3. E. coli, Staph. aureus, and Pseudomonas aeruginosa could not be detected with the test sample. 4. The number of confirmable mycotic contamination in the test samples has been revealed as 17 items (20.7%). 5. Chiefly, the causative organisms of the contamination are proved to be bacilli and fungi broadly distributed in nature. 6. Generally, the neutrality of the pH had greatly increased the number of products unsuitable on the specification of TVB. pH >7.0 No. of unsuitable items 0/4 (0.0%) pH 6.0-7.0 No. of unsuitable items 4/9 (44.4%) pH 4.0-6.0 No. of unsuitable items 5/45(11.1%) pH <4.0 No. of unsuitable items 0/24(0.0%) 7. The viability of general bacteria has shown a rather decreasing tendency in time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.51-54
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• 1999

In this paper, the relativities, and the properties of various contaminants, which could give significant decrease in electrical insulation strength were investigated. For this investigation, the contamination degree was manually measured with brush-wiping method, and the ingredient of some specific sample was analyzed with ICP/MS. With the result, the influence of distance from sea, climatic condition contamination was investigated. And the difference in electrical properties of various salts in aquous solution was determined. Finally, we could get several significant result on the relativity and properties of contamination in various conditions

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.162-168
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• 2006

Recently, diagnosis techniques have been investigated to detect a Partial Discharge associated with a dielectric material defect in a high voltage electrical apparatus, However, the properties of detection technique of Partial Discharge aren't completely understood because the physical process of Partial Discharge. Therefore, this paper analyzes the process on surface discharge of polymer insulator using wavelet transform. Wavelet transform provides a direct quantitative measure of spectral content in the time~frequency domain. As it is important to develop a non-contact method for detecting the kaolin contamination degree, this research analyzes the electromagnetic waves emitted from Partial Discharge using wavelet transform. This result experimentally shows the process of Partial Discharge as a two-dimensional distribution in the time-frequency domain. Feature extraction parameter namely, maximum and average of wavelet coefficients values, wavelet coefficients value at the point of $95\%$ in a histogram and number of maximum wavelet coefficient have used electromagnetic wave signals as input signals in the preprocessing process of neural networks in order to identify kaolin contamination rates. As result, root sum square error was produced by the test with a learning of neural networks obtained 0.00828.