• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.187-190
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• 1999

To reduce the maintenance expence, and the possibility of electric outage and accident, accurate measurement should be carried. But the classical method has some problems in the aspect of man power, reliability, and expence. In this paper, we propose a new type apparatus, which could detect the degree of contamination on insulators on outdoor insulation system, such as transmission and distribution line insulator and bushing. The new type apparatus consists of Pelltier module, electrode system, and measuring part. At first leakage current detecting method was considered, then with the fault(oxidation of electrode) of that method we should propose a another method. We carried various test to prove the possiblity and reliability of the propoused apparatus. And we get some useful result with laboratory test.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1513-1514
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• 2006

In this paper, there have been brief review about the important consideration in laboratory planning and construction of the artificial pollution testing facilities including 300 kV, 1800 kVA AC test system, which enable to lest and evaluate the UHV dielectric performance of power insulators up to transmission class. Also it is described simply about its trial running of the whole test system. To evaluate the performance characteristics against contamination for various power installation, especially for the insulators and kinds of bushings, brief investigation and an analysis of test objects and related international codes and standards have been conducted.

• 조명전기설비학회논문지
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• 제30권1호
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• pp.49-54
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• 2016

There is needed the quard channel triple wave lengths pyroelectric infrared flame detector to recognize the unique characteristics of fire sources in various type. This system detects the triple wave lengths of infrared flame emitting maximum radient energy and scattering frequency of flame. The quard channel infrared flame detector detects the duplicate wave lengths of maximum radient energy to enhance the accuracy of detecting fire. Especially this paper focuss on development of the self diagnosis function system including contamination, temperature and input voltage. Therefore, the prevention and early suppression of fire is available.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.1-6
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• 2023

In CO₂ laser surface machining of plastic films in modern display manufacturing, scattering of fume particles could be a major source of well-recognized film surface contamination. This computational fluid dynamics research investigates the suction air flow patterns over a film surface as well as the dispersion of micron-sized fume particles with low-Reynolds number particle drag model. The numerical results show the recirculatory flow patterns near laser machining point on film surface and also over the surface of vertical suction slot, which may hinder the efficient removal of fume particles from film surface. The dispersion characteristics of fume particles with various particle size have been tested systematically under different levels of suction flow intensity. It is found that suction removal efficiency of fume particles heavily depends on the particle size in highly nonlinear manners and a higher degree of suction does not always results in more efficient particle removal.

• 한국축산식품학회지
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• 제44권1호
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• pp.19-38
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• 2024

Meat contains high-value protein compounds that might degrade as a result of oxidation and microbial contamination. Additionally, various pathogenic and spoilage microorganisms can grow in meat. Moreover, contamination with pathogenic microorganisms above the infectious dose has caused foodborne illness outbreaks. To decrease the microbial population, traditional meat preservation methods such as thermal treatment and chemical disinfectants are used, but it may have limitations for the maintenance of meat quality or the consumers acceptance. Thus, non-thermal technologies (e.g., high-pressure processing, pulsed electric field, non-thermal plasma, pulsed light, supercritical carbon dioxide technology, ozone, irradiation, ultraviolet light, and ultrasound) have emerged to improve the shelf life and meat safety. Non-thermal technologies are becoming increasingly important because of their advantages in maintaining low temperature, meat nutrition, and short processing time. Especially, pulsed light and pulsed electric field treatment induce few sensory and physiological changes in high fat and protein meat products, making them suitable for the application. Many research results showed that these non-thermal technologies may keep meat fresh and maintain heat-sensitive elements in meat products.

• 방사선산업학회지
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• 제18권2호
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• pp.101-107
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• 2024

Rapid screening for internal contamination by alpha- and beta-emitting radionuclides is essential in situations involving radiation workers or radiation accidents. This study focused on the use of urine samples and liquid scintillation counting to quickly and accurately assess contamination. Calibration of the alpha and beta detection areas ensured precise measurement results. The major radionuclides recommended for surveillance during accidents were also considered. This study evaluated the effectiveness of the method by examining various parameters, including the limit of detection, linearity, sensitivity, selectivity, accuracy, ruggedness, and blind test sample analysis. The liquid scintillation counting method is an effective tool for screening urinary samples to detect alpha- and beta-emitting radionuclides, particularly during radiation emergencies, despite some limitations in precision.

• 한국의료질향상학회지
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• 제7권1호
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• pp.72-89
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• 2000

Background : Various types of protective footwear have been used to minimize bacterial contamination in operating rooms. In recent years, debate has arisen concerning the need for use of such protective footwear. This study was designed to provide useful data about choosing shoes most suitable for the surgical environment. Methods : Between November, 1999 and January, 2000, we performed this experimental study by comparing effect of three types of shoes (i.e., disposable shoescover, operating room-restricted shoes, and ordinary shoes) on bacterial contamination of operating rooms equipped with two different ventilation systems (i.e., high air-change, low air-change) respectively. Data were collected during two- hour sham operations in which subjects and their activities were strictly standardized. Bacterial flora were sampled from the study area floor and air colony counts were measured. Results : In experiments involving high air-change ventilation system, there was a significant difference of floor contamination between three types of shoes, but no difference of air contamination. Under low air-change system, there was a significant difference of both floor and air contamination between three types of shoes. Conclusion : The results show that protective footwear would be unnecessary in the operating room with high air-change ventilation system, but it is important to choose suitable shoes carefully under low air-change system. Therefore, the use of outdoor shoes can be considered under high air-change system, but it would seem sensible to apply their first use in less bloody operations at the day surgery center or out-patient department to prevent transfer of body fluid into the outside environment.

• 환경위생공학
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• 제7권2호
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• pp.111-128
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• 1992

According to the increase of population and industrialization, the quality of our drinking water are becoming worse by the contamination of resources, production of THM and other halogenated hydrocarbons during the purifying process, the problem of corroded water supplying pipeline, and the water reservoir tanks, Many people choose groundwater to drink instead of city tap water, but sometimes we get report about groundwater contamination by wastes, swage, septic tank, etc. It is reported that in U. S. over 20% of population are drinking groundwater, but U. S EPA reported the groundwater contamination by pesticides, herbicides, fungicides, fertilizer, and various chemical substances. Craun, et at announced the groundwater contamination by bacteria which are related with poor installation of septic tank. Johnson and Kross mentioned aboutmethemoglobinemia by NO3-N originated from human and animal feces, organic chemicals, and fertilizer, and as the results the infant mortality could be risen. Some scientist also reported the high concentration of metals in groundwaters and some cation and anions, and volatile organic compou nds. Authors investigated 80 groundwaters in urban, agricultural, and industrial area during last 3 month(June - August) to check any drinking water quality parameters are exceeding the standards. The results were as follow. 1, The average value of ammonia nitrate were within the standard, but 11.76% of urban area were exceeded the 10 rpm standard, in agricultural area 42.3175 were exceeded, and in industrial area 20.2% were exceeded the drinking water standard of 10 ppm. the highest concentration was 29.37 ppd in industrial area. 2. The mean value of metals is not exceeded the standard, but there were some groundwater whose Mn value was 0.424 ppm(standard is 0,3 ppm) in urban area, 0.737 rpm in agricultural area, and 5.188 ppm in industrial area. The highest Zn value was 1.221 ppm (standard is 1.0 ppm)was found in industrial area. 3. The percentage of contamination by general bacteria was 8.82% in urban area, 15.38% in agricultural area, and 15.00% in industrial area. Escherichia coil group was also contaminated by 35.29% in urban area, 30.76% in agricultural area, and 30.00% in industrial area. 4, The pH value was within the standard which means there was no influence by acid or alkali chemicals, nor acid rain Through the above results, all the groundwater should be tested to check the safety for drinking water and should make some alternative methods suitable for drink.

• 한국산업보건학회지
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• 제25권2호
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• pp.202-210
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• 2015

Objectives: The purpose of this study was to examine clean room(C/R) structure, air conditioning and contamination control systems and to provide basic information for identifying a correlation between the semiconductor work environment and workers' disease. Methods: This study was conducted at 200 mm and 300 mm semiconductor wafer fabrication facilities. The C/R structure and air conditioning method were investigated using basic engineering data from documentation for C/R construction. Furthermore, contamination parameters such as airborne particles, temperature, humidity, acids, ammonia, organic compounds, and vibration in the C/R were based on the International Technology Roadmap for Semiconductors(ITRS). The properties of contamination control systems and the current status of monitoring of various contaminants in the C/R were investigated. Results: 200 mm and 300 mm wafer fabrication facilities were divided into fab(C/R) and sub fab(Plenum), and fab, clean sub fab and facility sub fab, respectively. Fresh air(FA) is supplied in the plenum or clean sub fab by the outdoor air handling unit system which purifies outdoor air. FA supply or contaminated indoor air ventilation rates in the 200 mm and 300 mm wafer fabrication facilities are approximately 10-25%. Furthermore, semiconductor clean rooms strictly controlled airborne particles(${\leq}1,000{\sharp}/ft^3$), temperature($23{\pm}0.5^{\circ}C$), humidity($45{\pm}5%$), air velocity(0.4 m/s), air change(60-80 cycles/hr), vibration(${\leq}1cm/s^2$), and differential pressure(atmospheric pressure$+1.0-2.5mmH_2O$) through air handling and contamination control systems. In addition, acids, alkali and ozone are managed at less than internal criteria by chemical filters. Conclusions: Semiconductor clean rooms can be a pleasant environment for workers as well as semiconductor devices. However, based on the precautionary principle, it may be necessary to continuously improve semiconductor processes and the work environment.

• 지질공학
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• 제28권4호
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• pp.727-740
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• 2018

불포화대 매질은 지하수면 상부층으로서 지하수에 의해 포화되어 있지 않거나 불연속적으로 포화되어 있는 층으로 정의된다. 불포화대의 특성은 토양층 하부로부터 지하수면까지 유동하는 오염물질의 저감에 영향을 미친다. 최근 지하수오염도 평가에서는 불포화대 매질의 이방성 및 불균질성을 고려하지 않고 투수성을 나타내는 가중치를 주는 문제점이 있다. 지질학적 매질들은 다양한 범위의 투수성을 갖는다. 표준화된 입도를 대상으로 투수성을 나타내는 가중치로 오염취약도 작성에 적용한다면 불포화대 지질특성을 고려하여 작성한 오염취약도보다 과대하게 작성될 것이다. 본 연구에서는 이방성의 불균질 불포화대의 투수특성을 알아보기 위하여 복수의 불포화층을 고려한 실내 칼럼실험을 실시하였으며, 이를 바탕으로 현장 시추자료에서 얻어진 불포화대 매질의 특성에 의한 평균 투수계수로 환산하여 기존의 불포화대의 가중치를 적용한 지하수오염취약도와 불포화대 매질특성을 고려한 지하수오염취약도를 비교한 결과 불포화대 매질특성을 고려한 지하수오염취약도가 현장의 수질 측정결과와 잘 일치한다.