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.

조팝나무 揷木時期 및 揷床土의 種類가 發根에 미치는 影響

趙鎭泰,尹汰,金泰重,洪承敏,白基燁 한국화훼연구회 1995 화훼연구 Vol.4 No.1

Cutting experiment was conducted to develop a mass propagation method for Spiraea prunifolia var. simpliciflora Nakai. The optimum season for hardwood cutting was between December and early April, but cutting could be done year-round by using rhizome. NAA treatment (100 ppm) was the most effective as rooting promoter. IBA and IAA were also found to be effective. The effect of sand, red clay, loam, silty loam and vermiculite had little differences in rooting especially when cuttings were done earlier than April 5.

CAPD환자에서 복강내 도관 말단부의 위치에 따른 도관전위율 및 도관유지율의 비교

정용희,이태원,김희진,임천규,김명재 대한신장학회 2001 대한신장학회잡지 Vol.20 No.3

터널내 자연환기력 변화에 따른 오염물질 거동특성

정태섭,임익현,유재연 全北大學校 附設 都市및環境硏究所 1997 都市 및 環境硏究 Vol.12 No.1

Because of a sudden increase of vehicles, the limit of road capacity occurred. We are, therefore, constructing the road tunnel over l㎞ for the maximization of land use. To supply safe driving conditions in the road tunnel, we are controlling the exhaust emissions with a forced ventilation facility. The purpose of this study is to investigate the ventilation efficiency and the characteristics of tunnel on the change of natural ventilation force. To carry out this study, Sola program is transformed to fit for the road tunnel and it was simulated. The tunnel with ventilation system of transverse type is used as a objective tunnel. The results of this study are as follows; 1. The larger a natual ventilation force, the better a ventilation efficiency. 2. It is required the ventilation system dealing with quickly a change of the tunnel surroundings because of accumulation of 5m/sec. 3. The contaminant distributions in the near of ventilation system are highly stagnant in the left-below parts of tunnel, the below parts of air supply system and the below parts of ventilation system.

말라리아 환자 32예의 임상적 고찰

정용희,백일현,김태형,김영식,이우인,서환조 대한화학요법학회 2000 대한화학요법학회지 Vol.18 No.1

목적 : 삼일열 말라리아는 국내에서 1986년 이후에는 박멸된 것으로 알려졌으나 1993년 이후 증가하는 양상을 보이고 있다. 이에 말라리아의 임상적 고찰을 통하여 이 질환을 이해함에 있다. 방법 : 1991년 1월부터 1999년 10월까지 반복적 고열과 오한을 주소로 본 병원에 내원하여 말초혈액 도말검사에 의해 말라리아 감염으로 확진된 32예의 환자에 대해서 후향적으로 조사하였다. 결과 : 1991년부터 1999년 10월까지 총 32명의 환자의 연도별 발생빈도는 각각 1991년에 1명, 1996년에 1명, 1997년에 3명, 1998년에 13명, 1999년에 14명이었다. 월별발생빈도는 7월과 8월에 집중적으로 발생하였다.(46.9%) 환자의 거주지는 경기 연천과 파주에 주로 분포되었다(53.1%). 성별발생분포는 32예의 환자중에 여자가 5명, 남자가 27명으로 남자가 더 많았다. 발병연령은 22세에서 87세까지 분포되었고 20-30대에 많이 발생하였으며 20대가 가장 많았다. 군인 및 제대자가 17명(59.4%)에 해당하였으며, 제대자의 평균 제대후의 기간은 10개월 정도였다. 가장 흔한 임상증상은 발열 및 오한이었다.(100%) 비장종대 및 간장종대는 각각 26명(81.3%), 3명(9.4%)에서 관찰되었다. 검사실 소견은 평균적으로 WBC 5.317/㎕, 혈색소 12.5±7.1g/㎗, 혈소판 78,906.3±68391.4㎕, GOT/GPT 43.7±26.7/49.6±57.3 IU/ℓ, Total bilirubin 1.6±0.9㎎/㎗를 보였다. 말초혈액 도말검사상 모두 P. vivax였다. 치료는 hydroxychloroquine과 primaquine의 치료에 잘 반응하였다. 결론 : 말라리아는 7월과 8월에 한국에서 호발하는 중요한 급성 열성 질환으로 조기 진단 및 치료에 보다 관심을 기울여야 할 것이다. Background : In Korea malaria has been rare, but since reemergence of indigenous vivax malaria in 1993, the number of cases of malaria have recently increased. We analyzed the cases of malaria who were treated in Kyung-Hee University College of Medicine with regard to define the clinical characteristics of malaria. Methods : We retrospectively analyzed of 32 cases of malaria admitted to Kyung-Hee University Hospital between 1991 and 1999. Malaria was diagnosed by peripheral blood smear. Results : Among a total of 32 cases, the number of yearly incidence of 1991, 1996. 1997, 1998 and 1999 were 1,1,3,13,14 respectively. It demonstrated the high incidence especially between July and August. The most patients (53.1%) resided in Yeonchon and Pajoo. Among them, 5 cases were female and 27 cases were male. The age distribution ranged from 22 to 76 year old. The high incidence of age was between 20's and 30's. Military solidiers and ex-soldiers are 17 cases(59.4 %). The most frequent symptom was fever and chills (100%). Splenomegaly and hepatomegaly were also observed in 81.3 %(26 of 32) and 9.4 %(3 of 32) respectively. The laboratory findings were WBC 5.317/㎕. Hb 12.5±2.1 g/dl. platelet 78,906±68,391.4/㎕. GOT/GPT 43.7±26.7/49.6±57.3 IU/L. LD 678.3±50.1 IU/L. total bilirubin 1.6±0.9mg/dl- The all cases were treated suscessfully with hydroxychloroquine and primaquine. There were no central nervous system complications and pulmonary edema. Conclusion : Malaria is one of the important acute febrile illness with the high incidence between July and August.

기분석 정보에 기반한 색인어 추출에 관한 연구

진정환,김태완 인제대학교기초과학연구소 2001 자연과학 Vol.5 No.-

본 논문에서는 기분석 사전정보를 이용한 색인어 추출 시스템을 제안한다. 일반적으로 형태소 분석 방법은 실행시에 어절마다 코드변환, 형태소분리, 원형복원 규칙을 통한 분석후보의 여과 등의 과정을 거쳐 형태소 분석을 수행하므로 실행 효율의 관점에서 효율적이지 못하다. 이러한 문제점을 완화하기 위하여 어절 단위의 기분석 사전에 의한 분석을 실시하여 색인어로 추출함으로써 실행효율을 개선할 수 있다. 또한 사전 미등록 어휘를 포함한 복합명사의 분해를 위하여 각각의 어절의 음절 패턴에 따라 분해를 실시하여 단위 명사를 추출하였으며 복합 명사 분리시 통계정보와 MNPR을 이용하여 분해모호성 문제를 해결하였다. 본 논문에서 제시한 색인어 추출시스템은 문서분류, 문서용약, 정보추출 등의 분야에서 유용하게 사용할 수 있다. In the paper, we propose an index term abstract system based on pre-Analysis information. Most morphological analysis methods require repetitive procedures of input character segmentation and lemmatization of constitument morphemes, filtering of candidate results through looking up lexicons, which causes run-time inefficiency. To alleviate such problem of run-time inefficiency, we extract index term use a method of morphological analysis based on pre-analysis of partial words, so as to enhance the run time performance of the system. Moreover, we proposed a method of using statistical information and MNPR(Minimal Noun Preference Rule)in order to segment compound nouns include unregistered noun. Proposed index term abstract system is used usefully document classification, document summarization, information retrieval.

블록 내 움직임 정보를 이용한 다단계 움직임 예측 알고리즘

곽내정,윤태승,한재혁,안재형 충북대학교 컴퓨터정보통신 연구소 2001 컴퓨터정보통신연구 Vol.9 No.2

본 논문에서는 불록 내의 움직임 정도에 따라 다단계의 볼록레벨을 설정하고, 그 블록레벨에 따라 각기 다른 다단계의 움직임 예측을 수행하는 다단계 움직임 예측 알고리즘을 제안한다. 제안방법은 3단계의 블륵 레벨을 설정하고. 각 불록 레벨에는 서로 다른 크기의 고정 블록을 설정한다 또한 각 블록 레벨에서 수행되는 움직임 예측에는 탐색 단계와 탐색 범위를 차등적으로 적용하였다. 이는 움직임이 없거나 적은 영역에서의 잉여 탐색 과정을 제거하여 계산적 효율성을 중대하고, 움직임 정도가 큰 영역에 대해서는 움직임 예측 과정을 심화시켜 예측의 정확성을 향상시킨다 실험 결과 프레임당 적은 수의 블록으로 고정된 크기의 볼록을 가진 전역 탐색 블록 정합 알고리즘보다 적은 예측 에러를 발생시켜 MSE를 20% 정도 감소시키며, 연산량을 95% 정도 절감하는 효과를 얻을 수 있었다. In this Paper. we Propose a multi-level block matching algorithm using motion information in blocks. In the Proposed algorithm, the block-level of a block is decided by the motion degree in the block before motion searching Procedure, and then adequate motion searching performs according to the block-level. The number of block-level is 3 step and different fixed-block sixte is assigned to each block-level. Also. in motion estimation of each block-level is differential applied search step and search area. Which imProves computational efficiency by eliminating an unnecessary searching Process in no motion or low motion regions. and brings more accurate estimation results by deepening motion searching process in high motien legions. Simulation results shew that the proposed algorithm brings the lower estimation error about 20% MSE(mean squared error) reduction with the fewer blocks per frame and the lower computational loading about 98% operational amount reduction than full search block matching algorithm with constant block size.

Thioacetamide에 의한 BALB/c 마우스 간의 시간별 약물대사효소 억제 양상 : A Time-Course Study

이정운,고우석,김갑호,배연경,하현정,한상섭,천영진,정태천 영남대학교 약품개발연구소 2001 영남대학교 약품개발연구소 연구업적집 Vol.11 No.-

Thioacetamide is a potent hepatotoxicant which requires metabolic activation by cytochrome P450s (P450s) for toxicity. In the present study, the elevation kinetic of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities by thioacetamide treatment was investigated in male BALB/c mice. Inaddition, the inhibitory effects of thioacetamide on liver microsomal P450 enzymes were further investigated. Thioacetamide at 100 mg/kg/ was treated intraperitoneally for 6, 12, 24, 36, 48 and 72 hr. The blood was collected at the designated time for assaying the serum enzyme activities. To determine the P450 isozyme-specific activities. ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), and benzyloxyresorufin O-debenzylase (BROD) activities were determined for P450 1A1, 1A2 and 2B1, respectively, in liver microsomal fractions. The activities of ALT and AST were started to be elevated 6 hr after thioacetamide treatment andreached the maximun at 36 hr after the treatment. The elevated activities were dramatically recovered at 72 hr. The microscopic exmination of the liver specimen also showed a similar profile of hepatotoxicity. All P450-associated enzyme activities were time-dependently inhibited by the treatiment with thioacetamide. The maximum inhibition of P450 enzymes was observed 36 hr after the treatment. Because the inhibition of P450 enzymes by thioacetamide was time-dependent, our present results suggest that thioacetamide might inhibit P450 enzymes in mechanism-based inactivation.

산국 (Chrysanthemum boreale) 휘발성 추출액 및 EDTA가 미생물 및 인체 치은 섬유아세포에 미치는 영향

차정단,김태영,우원홍,전병훈,김해경,유용욱,김강주,길봉섭 원광대학교 생체재료·매식연구소 2000 원광생체재료·매식 Vol.9 No.1

Chrysanthemum boreale (C. boreale) has been used for the treatment of furuncles, carbuncles, sores, conjunctivitis, headache, vertigo and swollen throats as a folk medicine in Korea, but there is little report about experiment evidence of antimicrobial activity. To investigate the antifungal and antibacterial activity of Chrysanthemum boreale(C. boreale) volatile substance and EDTA, the growth inhibition against Aspergillus nidulans (A. nidulans), Fusarium oxysporum (F. oxysporum), Alternaria mali(Al. mali), Candida albicans (C. albicans), staphylococcus aureus (S. aureus), Streptococcus pyogenes(S. pyogenes), streptococcus mutans (S. mutans), Escherichia coli(E. coli), Helicobacter pylori (H. pylori) and Porphyromonas gingivalis (P. gingivalis) was monitored by agar dilution and broth microdilution method. The antifungal effect of C. boreale on A. nidulans, F. oxysporum, Al. mali and C. albicans was shown at the concentration of 0.04%. The antibaterial effect of C. boreale on S. aureus, S. pyogenes, S. mutans and H. pylori was shown at the concentration of 0.04%. However, the growth was inhibited at the concentration of 0.04% irrespective of the presence of EDTA 0.125% was much higher than higher than that of several concentration of volatile substance. The minimum inhibitory concentrations of volatile substance were 0.16% against S. aureus, 0.04% against S. pyogenes, 0.02% against S. mutans, 0.40% against E. coli, and 0.18% against C. albicans. The growth of human gingival fibroblasts was not affected by C. boreale volatile substances at the concentration of 0.04%. These results indicate that volatile substance from C. boreale may have biologically toxic activities to the microorganisms.

금연이 재입원한 정신병 환자의 약물용량에 미치는 영향에 대한 예비 연구

박규태,신정호,안정숙 大韓神經精神醫學會 1997 신경정신의학 Vol.36 No.6

본 연구는 30명의 정신병환자를 대상으로 하여 동일환자에서 일정 간격을 두고 원주기독병원 정신과 병동에 흡연이 허용되던 시기에 입원했을 때와 금연병동 때 재입원했을 때 투약된 항정신병약물 용량과 항정신병약물의 부작용에 따른 benztropine과 propranolol 처방용량을 비교하여 다음과 같은 결과를 얻었다. 1) 평균 입원기간은 금연병동 입원동안은 46.0일로 흡연병동 입원동안의 61.1일과 비교하여 감소되었다. 평균 입원기간은 통계적으로 유의하게 감소되었고(p<0.05). 약 2/3의 환자가2일에서 92일간의 입원기간의 감소가 있었다. 2) Chlorpromazine 등가량으로 환산한 항정신병약물 용량은 흡연병동 입원시기 동안의 395.0mg과 비교하여 금연병동 재입원시기 동안에는 296.8mg으로 통계적으로 유의하게 낮았다(p<.01). 3) 정신분열증 환자(n=13)에게 투약된 benztropine 용량은 금연병동 재입원시기 동안에는 0.56mg으로 흡연병동 입원 동안의 0.14mg과 비교하여 통계적으로 유의하게 용량이 높았다(p<.05). 4) Propranolol 용량은 흡연병동 입원동안과 금연병동 재입원 동안에 유의한 차이가 없었다. 결론적으로, 흡연해온 정신병 환자는 금연함으로써 입원기간의 감소가 있었으며. 항정신병약물 용량이 줄어드는 반면 정신분열중 환자에서는 추체외로계 증상은 증가할 가능성이 있으므로 이에 대한 대비가 있어야 할 것이다. 그러므로 환자의 흡연상태는 항정신병약물의 용량과 부작용에 관한 고려에서 반드시 평가해야 할 중요한 변수중 하나임을 강조하고자 한다. This study was designed to investigate the effect of no-smoking on the pattern of medication for 30 re-admitted psychotic patients in the no-smoking(smoking-prohibited) ward, who had been admitted and medicated previously in the smoking(smoking-allowed) ward, in Wonju Christian Hospital, by comparing daily mean dosage of antipsychotics, benztropine mesylate, and propranolol administered in smoking state and in no-smoking state of the same patients. The results were as fo11ows : 1) The mean hospital stay was reduced to 46.0 days in no-smoking ward compared to 61.1 days in smoking-allowed ward. This means mean admission period was reduced significantly(p<0.05) and over two thirds of all subjects experienced reduction of hospital stay from 2 days to 92 days. 2) A statistically significant difference was found in the dosage of antipsychotics in all subjects. Calculated in terms of chlorpromazine equivalent the daily mean was 296.8 ± 180. 7mg in no-smoking state, and.395.0±232.2mg in smoking state(p <.01). 3) In schizophrenics(n= 13), the daily mean dosage of benztropine mesylate was 0.56±0.62mg in no-smoking state and 0.14±0.21mg in smoking state, showing a significant difference(p <.05). In bipolar group, the mean dosage in no-smoking ward was also smaller than in smoking ward, though not significant. 4) The difference of the daily mean dosage of propranolol between two states was not significant. In conclusion, in no-smoking state psychotic patients required less hospital stays and significantly lower dosage of antipsychotics, and the schizophrenics required significantly higher dosage of benztropine mesylate for extrapyramidal symptoms. The authors suggest that psychiatric patients should be encouraged to stop smoking and recommend that psychiatrists monitor smoking state of their psychotic patients for proper and efficient drug therapy.