Study on Reliability Improvement of Voltage Transformers by Increasing Voltage Factor

Tae‑Sik Kong,Hee‑Dong Kim,Hung‑Sok Park,Soo‑Hoh Lee,Soon‑Yong Kim,Pil‑Bum Joung,Jin‑Yeub Park 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.3

Voltage transformers (VTs) must be highly reliable as they are essential components of the electric power industry. VT failures can cause a signifcant impact for important facilities such as nuclear power plants. In fact, VTs which passed the international standard, were damaged and sometimes resulted in the shutdown of the nuclear power plants. In order to improve the reliability, VTs with various iron core was studied. The electromagnetic feld simulation, a saturation characteristics test, and an overvoltage breakdown test were conducted. The result shows that the magnetic fux density signifcantly afects the reliability of VTs. To increase the reliability of VTs, it is required to reduce the magnetic fux density by increasing the knee-point and voltage factor. Owing to limited installation space, increasing the size of the iron core is difcult. Instead, VT by decreasing the thickness of the conductor and increasing the number of turns, it was possible to reduce the magnetic fux density without the size change. Therefore, improved VTs were obtained by decreasing the thickness of the conductor and increasing the number of turns, and the improved reliability was verifed through a comparison test with existing VTs. The fabricated VTs shows a signifcantly higher saturation voltage and breakdown time than existing VTs. Thus, by proposed VTs can contribute the stable operation of the nuclear power plant and improve the manufacturer’s quality.

한국산 약용식물의 화장품천연소재로서 응용에 관한연구

안봉전,이진태,이순애,곽재훈,박정미,이진영,박태순,손준호 경산대학교 생명자원개발연구소 2003 생명자원과 산업 Vol.7 No.-

Biological activities and application of sanguisorbae officinalis L. were investigated. In the enzymological physiological activities, the electron donating ability(EDA) was 54.92% in 10 ppm and it was over 90% over 50ppm and SOD-like activity was high as 65.36% in 1000 ppm, it was gradual increased. As inhibitory effect of xanthine oxidase, it was 17.90% in 200 ppm and a little low as 36.89% in 500 ppm and inhibitory effect of tyrosinase, it was a little low as 20.45% below 1000 ppm. As the result of measuring the lipid oxidation, all the concentrations of medical ion treatments had the ability to keep it from acidification and metal ion blocking effects about the lipid oxidation promoting factors(Fe^(2+) and Cu^(2+)), Fe^(2+) was better than Cu^(2+) and all concentrations of medical ion treatments was 40% in 50ppm. When it was applied into normal skin-softener it showed safe effect so that we can expect that as the natural material of cosmetics.

천안지역 일부 다중이용시설의 포름알데히드 농도에 관한 연구

전혜리(Hye-li Jeon),조수연(Su-yeon Jo),조혜란(Hye-ran Jo),조태진(Tae-Jjn Cho),박종안(Jong-an Park),손부순(Bu-soon Son) 대한환경위생공학회 2009 대한환경위생공학회지 Vol.24 No.2

This study was conducted at a Terminal, a Parking Lot, an Underground shopping center, a Funeral hall and a Hospital waiting room of Cheon An area in August 2008 to examine the concentration level of HCHO(formaldehyde). The concentration level of the remodeled sites were 39.4 ± 12.0 ㎍/㎥ in the terminal, 32.7 ± 7.3 ㎍/㎥ in the parking, and 97.8 ± 29.4 ㎍/㎥ in the underground shopping center. The underground shopping center had the highest level and followed by the terminal and the parking. On the contrary, the site remodeling had the level of 17.7 ± 12.4 ㎍/㎥ in the funeral hall and 17.9 ± 0.6 ㎍/㎥ in the hospital waiting room. The funeral hall had highest level than that of the hospital waiting room. Both the remodeled sites and the not remodeled site had concentration level of HCHO below the standard level, but it was higher in the remodeled sites. There were no relations among the HCHO, the temperature and the humidity in facilities of Cheon An area.

중심관이 있는 고효율 축상 유입식 싸이클론 집진기 수치해석적 연구

박지영,장동순,엄태인 忠南大學校 産業技術硏究所 1994 산업기술연구논문집 Vol.9 No.2

A numerical study has been performed in order to investigate the performance of two different shapes of axial-vane type cyclones. The first is a standard type and the other is the one with a central body of the form of an annular tube. Numerical calculations are made using a well-known Patanker's methodology. That is, a control-volume based finite difference method is employed together with the power-law scheme for the descretization of the convection term appeared in governing equation. The pressure-velocity coupling is resolved by the use of the revised version of SIMPLE, say SIMPLEC. The Reynolds stresses are closed using the standard k-ε model. The general pattern of fluid motion is resolved together with the particle trajectory behavior for 8 different particle sizes as a function of swirl strength and central body. The calculation data are in good agreement with the empirical knowledge, for instance, the effect of swirl intensity. The cyclone with a central body shows a high removal efficiency of particulate but more pressure drop than a standard one. Further discusstions are made in detail.

생물학 탐구에서 학생들이 생성한 가설검증방법의 유형

박순화,고경태,정진수,권용주 한국과학교육학회 2005 한국과학교육학회지 Vol.25 No.2

이 연구의 목적은 학생들의 생물학 가설검증방법의 유형을 분류 데 있다. 이를 위해 고등학생 35명과 대학생 40명을 표집 하여 수국, 제비 나비, 감자즙, 펭귄 등 4개의 가설검증 과제를 투입하였다. 각 과제에서 연구대상 학생들은 현상을 관찰하여 인과적 의문을 생성하고, 집단토의를 통해서 하나의 가설을 생성하였다. 그런 후 스스로 생성한 가설을 검증할 수 있는 방법을 고안하였다. 연구자들은 이렇게 고안된 학생들의 가설검증방법을 분석하여 몇 가지로 유형화하였다 그 결과에 의하면 먼저, 하나의 원인으로 된 가설의 검증유형은 직접 관찰법, 유사현상 비교법, 긍정 비교법, 긍정-부정 비교법, 비례 비교법 등으로 분류되었다 그리고 여러 개의 원인으로 된 가설은 크게 부분 검증법과 전체 검증법으로 구분되었고, 부분 검증법은 다시 단일 유형과 다수 유형의 하위 유형으로 구분되었으며, 전체 검증법은 유기적 유형, 기계적 유형, 혼합 유형 등의 하위 유형으로 구분되었다. The purpose of this study was to analyze the college students' and high school students' testing methods for biological hypotheses. Subjects were 35 11th grade students and 40 college students. Four hypothesis-testing tasks were developed and administered to the subjects: hydrangea, swallow butterfly, juiced potato, and penguin tasks. After being presented with the phenomena of the tasks, students were asked to generate questions and hypotheses and then to write a hypothesis-testing method on a questionnaire. Students' hypothesis-testing methods were classified into 5 types for mono-cause hypotheses; direct observation, similar phenomenon comparison, positive comparison, positive-negative comparison, and proportion comparison. In addition, students' hypothesis-testing methods were classified into 5 types for multi-cause hypotheses; mono type, poly type, organic type, mechanic type, and mixed type. This study also discussed the implications of these findings for teaching and learning in science education.

기능성 Catechol-O-Methyltransferase 유전자 다형성과 한국인 정신분열병의 관련성

박태원,홍영준,박임순,김형섭,최인미,배수영,윤경식,강대희 大韓神經精神醫學會 2001 신경정신의학 Vol.40 No.4

연구목적 : Catechol-O-Methyltransferase(COMT)는 카테콜아민 신경전달물질의 불활성화를 담당하는 효소로서, 정신분열병과 관련된 후보 유전자로서 알려져 왔다. 최근, 기능성 COMT유전자 다형성과 정신분열병의 관련성이 제기되었는데, 한국인 정신분열병에서도 이러한 관련성이 있는지를 살피기 위해 본 연구를 시행하였다. 방 법 : 정신분열병으로 진단된 환자군 103명과 성별 및 연령별로 1:1 짝짓기 대조군 사이에 유전자형과 대립유전자의 분포를 비교하였다. 또한, 환자군은 공격적 행동, 가족력, 아동기 발병 여부에 따라 두 군으로 나누어 비교하였다. DNA의 다형성 부의를 중합효소연쇄반응에 의해 증폭한 후 ,NlaⅢ제한효소법과 전기영동을 실시하여 유전자형을 판별하였다. 결 과 : 환자군 전체와 대조군 사이에 유전자형과 대립유전자 빈도의 차이가 없었다. 가족력이 있는 환자군을 대조군과 비교하였을 때는, 대립유전자 L을 포함하는 유전자형과 그렇지 않은 유전자형의 분포에 있어 유의한 차이를 보였다(p=0.02, OR=3.9, 95% Cl=1.1∼14.3). 결 론 : 한국인 정신분열병과 기능성 COMT 유전자 다형성 사이에 유의한 관련성이 없었다. 따라서, 기능성 COMT 유전자 다형성이 한국인 정신분열병의 발병에 영향을 주지 못한다. 그러나, 정신분열병 가족력과 기능성 COMT유전자 다형성의 관련성이 시시돠어, 향후 본 연구에서 나타난 방법론적인 문제점을 보완하고 추가 대상자를 확보한 연구가 필요하다. Objectives : Catechol-O-methyltransferase(COMT) is involved in the degradation of catecholamine meurotransmitters and has been investigated as a candidate gene in schizophrenia. Recently, possible relationship between functional COMT gene polymorphism and schizophrenia has been suggested. To address the possible role of functional COMT gene polymorphism in the predisposition to schizophrenia, we carried out an association study in Korean schizophrenic patients and controls. Methods : One hundred and three Korean inpatients diagnosed as schizophrenia and 103 age and sex matched controls were selected as study subjects. Patients were subgrouped into two groups on the basis of history of aggressive behavior, family history of schizophrenia and related disorders, and age at onset. We determined COMT genotypes using PCR of the relevant region followed by digestion with NlaⅢ and electrophoresis. Results : No significant differences of allele and genotype frequencies were noted between patients and controls. However, when patients were categorized by the presence of family history of schizophrenia and related disorders, patients with family history showed almost 4 fold higher frequency of having COMT L allele containing genotype compared to controls(p=0.02, OR=3.9, 9.5% CI=1.10-14.33). Conclusion : Although our results do not support an association between functional polymorphism of COMT gene and schizophrenia overall, the findings suggest an association between functional COMT gene polymorphism and familial schizophrenia. Further studies with large samples are needed to confirm this association.

筋小胞體의 ATPase Kinetics에 關한 硏究

朴映淳,李承兩,朴泰水,庾基洙,李 弘,金允坤 圓光大學校 1982 論文集 Vol.16 No.2

본 연구에서는 토끼 골격근 소포체에서 분리한 근소포체의 ATPase활성에 대한 일반적 특성과 수종의 2가 양이온(??)의 영향에 관한 연구를 하였다. ATPase활성과 Ca uptake에 미치는 2가 양이온의 저해 효과와 저해기작은 Dixon plot, Lineweaver-Burk plot, Hanes-Woolf plot, Woolf-Augustinsson-Hofstee plot, Eadie-Scatchard plot, Arrhenius plot등을 이용하여 분석하였으며 그 결과는 다음과 같다. 1. 근소포체의 ATPase는 ??과 ??의 존재하에서 활성화 되어지며 ??의 농도가 4mM일 때 ??의 최적 농도는 0.1mM이었다. 2. 근소포체의 ATPase는 ??-ATPase와 (??)-ATPase로 구성되어 있고 (??) - ATPase의 활성은 ??-ATPase의 활성보다 높았다. 3. ATPase의 활성화 에너지는 약 19Kcal/mol이었다. 4. ATPase 활성에 미치는 2가 양이온은 12.5㎛과 400㎛의 범위 내에서 이온 농도가 증가됨에 따라서 활성도는 점점 감소되었다. 5. ATPase활성율 50% 저해시키는데 2가 양이온의 농도는 Ki값과 같아서 ??, ??, ?? Pd ??에 대한 각각의 농도는 10㎛, 30㎛, 130㎛ 및 350㎛이었다. 특히 ??은 저 농도에서 (12.5-100㎛)는 활성제로, 고농도에서 (200-400㎛)는 저해제로 작용하는 것 같다. 6. 2가 양이온은 ATPase의 Km에는 변화를 주지 않으나 Vmax의 저하를 일으키는 것으로 보아 비경쟁 저해제임이 판정되었다. 7. 2가 양이온은 가역적 저해제임이 판명되었다. 8. Ca 吸收能에 대한 CuCl₂의 阻害는 50~500㎛의 CuCl₂농도에서 현저히 나타났으며 이 현상은 Ca 吸收能과 ATPase 活性과 밀접한 관계를 보여주는 것이다. General properties of the ATPase and the effects of the divalent cations (??) on the total ATPase activity of the fragmented sarcoplasmic reticulum (FSR) isolated from rabbit skeletal muscle were investigated in the present resent research. The inhibitory effect of divalent cations on the FSR ATPase activity and its mechanism were analyzed by various plots such as Dixon plot, Lineweaver-Burk plot, Hanes-woolf plot, Eadie-Scatchard plot and Arrhenius plot. The results obtained were as follows: 1. The FSR ATPase is activated by ?? and ??; the optimum concentration of is 0.1 mM in the presence of 4 mM MgCl₂. 2. The FSR ATPase could be distinguished as ??-ATPase and (??)-ATPase. The activity of (??)-ATPase predomiant over that of ??-ATPase. 3. The apparent energies of activation for total ATPase was approximately 19Kcal/mole. 4. The inhibitory effects of the divalent cations on the enzyme activity increased as the concentrations of the divalent cations increased in the concentrations between 12.5 and 400㎛. 5. Concentration of 50% inhibition for each divalent cation was almost identical with the inhibition constant (ki). The Ki's were 10,30,130, and 350㎛ for ??, ??, ??, and ??, respectively. ?? seemed to be anactivator at lower concentrations and an inhibior at higher concentratios. 6. The divalent cations did not change the Km but decreased the Vmax of the FRS ATPase, suggesting that they are noncompetitive inhibitors on the FSR ATPase. 7. The divalent cations were also found to be revesible inhibitors on the FSR ATPase. 8. The inhibitory effect of CuCl₂on a uptake increased as the concentration CuCl₂increased in the range between 50㎛.

용액법에 의한 나노세공 TiO₂의 합성(Ⅰ)

박태순,김호건 한양대학교 이학기술연구소 2006 이학기술논문지 Vol.9 No.-

금속염을 이용한 용액 침전법과 Alkoxide를 이용한 Sol-Gel법에 의하여, 나노세공 TiO₂ 분말을 합성하고 이를 촉매담체로서 사용하기 위해 수열처리를 통하여 물성을 조절하였다. 분말합성시 용액침전법에서는 70℃, 0.55M의 조건으로, Sol-Gel법에서는 실온(25℃)에서 pH 10의 조건으로 합성하였고 반응시간은 3시간으로 동일하게 하였다. 합성된 분말의 수열처리는 80∼200℃에서 3∼24시간동안 진행하였다. 합성된 분말의 결정상 및 미세구조를 확인하기 위하여 XRD, FT-IR, SEM 등의 기기를 사용하였다. TiO₂ powders with nanopores were synthesized via aqueous precipitation methods using metal salts and via Sol-Gel methods using alkoxide. To use these TiO₂ powders as biocatalyst supports, their physical properties were controlled through hydrothermal treatments. In the aqueous precipitation methods, TiO₂ powders were synthesized under the conditions: reaction temperature 70℃, reaction time 3hours and metal salt concentration 0.55M. In the Sol-Gel methods, TiO₂ powders were synthesized under the conditions: reaction temperature 25℃ reaction time 3hours and solution pH10. The conditions for hydrothermal treatment are as following: temperature 80∼200℃ and heat treatment time 3∼24hours. For the charactenzation of the obtained powders, XRD, FT-IR and SEM techniques were used.

High Impact Polystyrene의 難燃化와 그 熱安定性에 關한 硏究

朴利淳,朴鍾論,安泰玩 울산대학교 1978 연구논문집 Vol.9 No.1

High Impact Polystyerne(HIPS)의 難燃化를 爲하여 세 種類의 Bronine 系 難燃劑를 ASTM-D 635 에 依해 試驗하여 難燃劑 單獨으로 쓸 때의 要求量을 求하였고, 相乘效果劑 Sb₂O₃를 添加했을 때의 難燃劑/Sb₂O₃ 比率을 決定하였다. 또 HIPS의 難燃化에 따르는 熱安定性 實驗을 하여 各 難燃劑에 對해서 가장 좋은 安定劑의 種類 및 濃度를 求하고, 安定劑 등 難燃劑 以外의 成分이 混合될 때에 그것들이 難燃性에 미치는 影響을 檢討하였다. Three kinds of Bromine type Fire-retardants were tested in the High Impact Polystyrene(HIPS) by ASTM-D-635. The amount of each fire-retardant was given when the fire-retardant was used only, and used with the synergist antimony trimony trioxide. And the thermal stability of flame-retardant HIPS was tested when various stabilizers were added. The effect of additives other than fire-retardant and synergist on the flammability of flame-retardant HIPS was discussed.

체육고등학교 유도선수들의 일반적 특성에 따른 만족도 연구

박순진,윤익선,김태훈 龍仁大學校 武道硏究所 2002 武道硏究所誌 Vol.13 No.1

This study is to investigate and clarify Life and Athletic Satisfaction of Physical Education Highschool Judo Athletes, based on 12 Physical Education Highschool Judo teams that are registered on Korean Judo Federation of Korean Sports Council in 2002. Among the physical Education Highschool Judo teams, 3 male teams and 3 female teams with winning experience over 3 times for 2 years, 2000-2001 and 3 male teams and 3 female teams without winning experience during the same period, and the responses of the 216 persons were applied to analyze actually. This study brings the follow conclusions by using statistical analysis such as reliability analysis, t-test, one-way ANOVA, correlation analysis, regression analysis, etc. First, Life satisfaction in accordance with the background factors depends on school grades and athletic career significantly. Second, Athletic satisfaction in accordance with the background factors depends on athletic career. Third, Life satisfaction in accordance with the background factors shows a positive correlation in winning prize or not(r=.211*), school grades(r=.212*), and athletic career(r=.268*), and a negative correlation between genders(r=-.265*). Also, athletic satisfaction in accordance with the background factors shows a positive correlation in winning prize or not(r=.200*) and athletic career(r=.158*), and a negative correlation between genders(r=.-336*). Forth, In accordance with the background factors school grades(β=.123) and athletic career(β=.217) effect on life satisfaction and the former (β=.-102) and the latter (β=.200) on athletic satisfaction.