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SPICE을 利用한 硅素鐵心의 渦流에 대한 MODELING에 關한 硏究
韓運東,柳然國,梁桂儁 충주대 산업과학기술연구소 1998 産業科學論文集 Vol.6 No.-
The relation between the equivalent eddy current field He and the instantaneous flux density rate dB/dt is experimentally obtained for current transformer made of silicon steel. The results show that He is proportional to(dB/dt)-0.5~0.7 in the operating frequency range(~100Hz) of the current transformer. The AC B-H loop calcurated by combining the Jiles-Atherton model agrees well with the measured data. In addtion, this combined model allows magnetic component characteristics using SPICE to be simulated. The simulated secondary voltage waveforms of current transformers are in satisfactory agreement with the measured values.
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오병수,김경숙,주설,강준원 한국물환경학회 2004 한국물환경학회지 Vol.20 No.3
This study investigated the micropollutants present in raw water supplied for the several drinking water treatment plants in Seoul. The target sample waters were collected from the several sites, such as Jayang (JY), Kuui (KI), Paldang (PD) and Kangbuk (KB) at the Han-River stream. The analytical method used in this study enable us to detect about 300 kinds of chemicals commonly found in surface water at ppt level by GC-ion trap MS. In this study, the consideration on the analytic results focused on the four hazardous organics, such as benzenes, phenols, phthalates and pesticides. The numbers of each detected micropollutant were 1~8 kinds for benzenes, 1~7 kinds for phenols, 5~7 kinds for phthalates and 1~9 kinds for pesticides. For the pesticides, the higher concentration was detected in the water samples collected from PD and KB adjacent to the farming area, and at June and July, which is the busy farming season. The total concentrations of each micropollutants detected at all the sites were significantly lower than those of drinking water regulation in Korea as well as other advanced countries. However, the frequently detected micropollutants requires the steady and precise monitoring for the effective management of drinking water source.
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이혜영,--,--,--,--,--,-- THE KOREAN SOCIETY FOR BIOMEDICAL LABORATORY SCIEN 2003 Journal of biomedical laboratory sciences Vol.9 No.3
Since water borne infection causes acute diseases and results in spread of diseases by secondary infection, the prevention is very important. Therefore, it is necessary to have a method that is rapid and effective to monitor pathogenic bacteria in drinking water. In this study, we employed a systematic method, Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) analysis, to develop an effective monitoring system for possible bacterial contaminants in drinking water. For this purpose, PCR primers were derived from 992 bp region of the 16s rRNA gene that is highly conserved through the different species of prokaryotes. To test whether the PCR primers designed are indeed useful for detecting all the possible microbial contaminants in the water, the primers were used to amplify 16s rRNA regions of different microbial water-borne pathogens such as E. coli, Salmonella, Yersinia, Listeria, and Staphylococcus. As expected, all of tested microorganisms amplified expected size of PCR products indicating designed PCR primers for 16s rRNA indeed can be useful to amplify all different microbial water-borne pathogens in the water. Furthermore, to test whether these 16s rRNA based PCR primers can detect bacterial populations present in the water, water samples taken from diverse sources, such as river, tap, and sewage, were used for amplification. PCR products were for then subjected for cloning into a T-vector to generate a library containing 16s rRNA sequences from various bacteria. With cloned PCR products, RFLP analysis was done using PCR products digested with restriction enzyme such as Hae Ⅲ to obtain species-specific RFLP profiles. After PCR-RFLP, the bacterial clones which showed the same RFLP profiles were regarded as the same ones, and the clones which showed distinctive RFLP profiles were subsequently subjected for sequence analysis for species identification. By this PCR-RFLP analysis, we were able to reveal diverse populations of bacteria living in water. In brief, in unsterilized natural river water, over 60 different species of bacteria were found. On the other hand, no PCR products were detected in drinking tap-water. The results from this study clearly indicate that the PCR-RFLP-sequence analysis can be a useful method for monitoring diverse, perhaps pathogenic bacteria contaminated in water in a rapid fashion.
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The Kinetics of the Sonochemical Process for the Destruction of Aliphatic and Aromatic Hydrocarbons
Kang, Joon Wun,Koh, Chang Il,Lee, Kyung Hyuk,Nam, Seong Nam 한국화학공학회 2001 Korean Journal of Chemical Engineering Vol.18 No.3
The sonochemical destruction of volatile organic compounds in aqueous solution has been investigated by using TCE (trichloroethylene), PCE (tetrachloroethylene), benzene, and toluene as model compounds. The substrate's destruction was observed to be decreased at a pseudo first-order rate, and the rate of TCE decay (k。=1.7×10^(-3) s^(-1)) was the greatest when the initial concentration of TCE was 380 μM. The effect of initial concentrations of TCE (ranging from [TCE]。=8.5-424 μM) on the overall decomposition rate of TCE,k。_TCE was investigated. The K。value decreases with the increase of [TCE]。to the level of 200 μM. But, the stays constant increasing the [TCE]。further. The effect of bicarbonate on TCE decomposition at low concentrations was investigated. The bicarbonate affects TCE decomposition insignificantly in the spiked bicarbonate range of 1 to l0 mM. The sonolytic rate of degradation of TCE appears to be enhanced by the presence of ozone, and the enhancement degree was quite significant at low concentrations of substrate. A kinetic model study was attempted to elucidate the specific reaction sites of the tested compounds and the major contribution of destruction route (OH·eaction or pyrolysis reaction) depending on the various conditions.
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UV/Oxidation Process for Destruction of Hazardous Chemicals
Kang, Joon-Wun,Koh, Chang-Il,Lee, Sang-Joon,Kan, Eun-sung 嶺南大學校 環境問題硏究所 1998 環境硏究 Vol.18 No.1
ABSTRACT This paper focuses on the use of UV/Oxidation systems such as ozone with ultraviolet irradiation and photolysis of hydrogen peroxide with ultraviolet radiation. The two different UV sources, the low pressure Hg arc and the medium pressure Hg arc were used and compared in this study. In experiments concerning the direct photolysis of aqueous CCI4, a medium pressure Hg arc has advantage over the low pressure Hg arc. In the H2O2/UV process, the low pressure Hg ard is economical than the medium-pressure Hg in terms of OH radical generation from the UV photolysis of hydrogen peroxide. In the Ozone/UV process, the photolysis rate of ozone with the two types of UV sources was compared. The results shows that the photolysis rate of ozone by the low pressure Hg arc is as fast as the medium pressure Hg arc even with the much lower energy UV power. An experimental set-up to determine the absorbed photon in the photo-reactor has been suggested from the precise measurement of ozone photolysis rate. This paper focuses on the use of UV/Oxidation systems such as ozone with ultraviolet irradiation and photolysis of hydrogen peroxide with ultraviolet radiation. The two different UV sources, the low pressure Hg arc and the medium pressure Hg arc were used and compared in this study. In experiments concerning the direct photolysis of aqueous CCl_4, a medium pressure Hg arc has advantage over the low pressure Hg arc. In the H_2O_2/UV process, the low pressure Hg arc is economical than the medium-pressure Hg in terms of OH radical generation from the UV photolysis of hydrogen peroxide. In the Ozone/UV process, the photolysis rate of ozone with the two types of UV sources was compared. The results shows that the photolysis rate of ozone by the low pressure Hg arc is as fast as the medium pressure Hg arc even with the much lower energy UV power. An experimental set-up to determine the absorbed photon in the photo-reactor has been suggested from the precise measurement of ozone photolysis rate.
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Characterization Method of Raw water for the Ozone Application in Drinking Water
Kang, Joon-Wun,Park, Hoon-Soo 嶺南大學校 環境問題硏究所 1999 環境硏究 Vol.19 No.1
ABSTRACT A study has been conducted to investigate the ozone decomposition kinetics in natural water and to determine its potential to produce OH●for the oxidation of micropollutants during the ozonation process. Our specific instrument designed with the FIA(Flow Injection Analysis) technique enabled us to measure the ozone decomposition rate, which is usually consists the two stages, the instantaneous ozone consumption phase and the slower ozone decay phase. The ozone consumption rate at the initial phase and the secondary phase can be represented with the parameters called the instantaneous ozone demand (ID) and the first-order decay rate constant (K C). The yield of OH radicals per consumed ozone (Ra) are measured using the OH● -probe compounds such as PCE(Perchloroethylene) and PCBA(p-chlorobenzoicacid). The amounts of ID values are significant in the non-filtered natural water system, and substantial amounts of OH● are found produced during the initial ozone consumed phase. The three parameters, such as ID, KC and Ra can be used as a valuable parameter to characterize a raw water for planning and optimizing the ozonation process of drinking water.
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