복합 적층 박판의 열응력 파손에 대한 진동 활용 비파괴평가

이성혁,이정기,최낙삼 韓國非破壞檢査學會 1999 한국비파괴검사학회지 Vol.19 No.5

두께 1mm의 얇은 복합적층판의 자유경계단부에서 열응력으로 인해 발생하는 미세손상을 진동거동과 관련된 비파괴평가의 가능성을 연구하였다. 유한요소 열응력해석을 통해 예상되는 손상발생영역을 초음파 C-스캔과 광학현미경을 이용하여 관찰하였다. 사인 스윕시험을 이용한 적층보 시험편의 횡진동 해석결과, 미세한 내부손상으로 인해 고유주파수가 확실히 감소하였으며 감쇠비도 상당히 증가하였다. 길이가 짧은 적층보 시험편과 2차 모드의 공진주파수를 이용하여 얇은 적층판에서 열응력으로 유기된 미세손상을 매우 민감하게 평가할 수 있음을 알았다. A feasibility investigation on vibration-based nondestructive evaluation of thermal stress-induced micro failure in the free edge region of thin composite laminates(1mm thick) has been carried out. The failure occurrence and damage zone, which were predicted by the three-dimensional finite-element thermal stress analysis, were observed using the ultrasonic C-scan and optical microscopy. Analysis of the vibration spectrum measured from the laminate beam specimens by the vibration sweep test exhibited that the obvious decrease in resonancy frequency and some considerable increase in damping factor were associated with the micro-failure formation. The vibration technique utilizing short beam and high resonant frequency was found to be very sensitive to the thermal stress-induced damage in the thin laminates.

Zeolite X 촉매를 이용한 WO₃의 CO 환원-탄화반응

이동활,이종대,전진혁,박노국,류시옥,이태진 嶺南大學校 工業技術硏究所 2003 工業技術硏究所論文集 Vol.31 No.2

This study was performed to manufacture tungsten carbide from CO reduction- carburization of WO₃using zeolite-NaX catalyst. Zeolite-NaX catalyst could improve the reduction property of WO₃. Moreover, zeoite-HX and KX catalysts also improved the reduction property of WO₃. This improvement of reduction property leaded to the decrease of reaction temperature. The size of WC particle was 50∼60 nm at 650 ℃ for 10h. From these results, it is concluded that the various zeolite X catalysts could be used for the reduction-carburization of W0₃ as the catalysts.

다가야스병에 의한 돌연사 부검 1예

이재혁,조승제,박종태 大韓法醫學會 1994 대한법의학회지 Vol.18 No.1

A 22-year old male patient was admitted to the Emergency room of local clinic because of the stuporous mental status. On physical examination, he appeared as a chronically ill, slender man. There was complete absence of the left arm pulse, and a prominent thrill and briuts were present over the right subclavicular area. The blood pressure which checked in the other regions except for the left arm was hypertensive(right arm 180/100, right leg 210/120, and left leg 200/130mmHg). An x-ray film of the chest and doppler ultrasounds showed characteristic dilatation of aortic arch, ascending aorta and innominate artery. The clinical impression was Takayasu's disease. This patients's condition deteriorated rapidly in spite of intensive care and died on the seventh hospital day. At autopsy, the cause of death was massive left brain infarction due to middle cerebral artery embolization. The opened luminal surface of the aorta and its major branches revealed irregulary thick-walled, tree-bark-like appearance. Also in the left common carotid artery, the lumen was nearly obliterated by thromi and intimal fibrous plaques. But the thoraco-abdominal aorta was spared. Microscopic examination disclosed granulomatous and sclerosing arteritis. In the former, the inflammatory process was confined to the media and adventitia and the cell infiltrate consisted predominantly of lymphocytes, plasma cells and histiocytes, with a varying number of giant cells. The latter was characterized bland intimal fibrous hyperplasia, medial degeneration with disrupted elastic lamella, and adventitial fibrosis. The pathologic diagnosis was Takayasu's disease of type I.

저열팽창성 Fe-29Ni-17Co 코바 합금의 고온균열 발생과 고온연성에 미치는 S 및 Mn의 영향

이기안,박종혁,조봉현,남궁정,김문철 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.12

The effect of S & Mn on the hot ductility of Fe-29Ni-17Co Kovar alloy and the mechanism of high temperature cracking occurrence were investigated. It has been found that the brittle intergranular fracture at high temperature cracking is closely associated with the sulfide along grain boundary. Experimental results showed, especially when the S content was high and the Mn content was free, that small cavities could be nucleated easily on FeS particles along grain boundary and propagated fast at high temperature. The hot ductility of Kovar alloy was drastically increased with the addition of Mn and it was also increased with decreasing S content. SEM and FE-SEM analyses showed that the Mn addition in this alloy could cause ductile intergranular fracture appearance below 1150℃ by the precipitation of MnS. It was proposed from the results that the addition of Mn and optimum S content (below 30 ppm) in Kovar alloy was necessary in order to reduce the hot cracking susceptibility.

종합병원 입원 환자에서의 불면증의 임상적 특징

이종국,유태혁,한창환 大韓神經精神醫學會 1991 신경정신의학 Vol.30 No.1

The purpose of this study is to investigate the clinical characteristics of insomnia in 300 new inpatients of general hospital with semistructured interview and questionaires. Among 4 clinical groups-129 noninsomniacs, 171 insomniacs (100 insomniacs with past insomnia history and 71 without past history), we compared the following variables ; age, sex, associated significant diseases, usual life habits, environmental variables influencing sleep pattern, types of insomnia, causes of insomnia, coping methods with insomnia, and usage of hypnotics. In insomniacs we also compared the changes of types and causes of insomnia, coping methods with insomnia after admission. The prevalence of insomnia was significantly increased after admission, and was higher in female patients but not significantly different in age. The frequencies of associated significant disease(angina, arrhythmia, asthma, duodenal ulcer etc.), naps, smoking, alcohol and coffee drinking showed no difference between insomniacs and noninsomniacs. Among environmental variables, “apprehension about illness”, “noise”, “nurse's visit”, and “bed discomfort”were significantly more frequent in insomniacs. Presence or absence of past insomnia history gave no significant effect on the types, causes of insomnia and coping methods with insomnia. Difficulty in maintaining sleep(DMS) was significantly increased after admission but difficulty in falling asleep(DFA) was decreased. The causes of insomnia were physical illness, sleep environmental variables, and psychological variables in order ; first two of these were significantly increased after admission. After admission as well as before admission, the most coping method with insomnia was “effort to forget problems”. Among the methods, “exercise or walking” was significantly increased after admission. Afterwards the study on the psychopathology and characteristics of personality which related with insomnia will be needed to broaden our understanding about insomnia and to establish proper management plan of insomnia.

월경주기 증상의 요인 분석

이수일,유태혁,강종선,안석철,이병욱,김헌,석재호 大韓神經精神醫學會 1986 신경정신의학 Vol.25 No.1

404 nurses and nurse-aids rated their experiences of 45 symptoms(Moos' Menstrual Distress Questionnaire) of the menstrual, premenstrual and intermenstrual phase on a 4 point scale separately. The 45 symptoms were inter-related and factor analyzed separately for each phase. six common clusters of symptoms emerged from 3 phases, which were labeled concentration, motor tension, pain, pleasurable affect, autonomic reactions and water retention. Four clusters of symptoms emerged from premenstrual phase. These clusters were labeled instabillity, withdrwal reactions, depression and headache. The factor named unpleasurable affect emerged from intermenstrual and menstrual phase. Above findings were differed from the results of Moos' study in which eight basically replicated clusters of symptoms emerged from three phases. Through discussion of validity of this scale, and differences between results of Moos' and this study, we came to the conclusion that sampling of subjects, prospective longitudinal symptoms reporting, amount of variance in a symptom over the course of menstrual cycle and proper choice of factor analysis method would be salient variables to construct valid scale for measuring menstrual cycle symptoms.

Mg합금의 선반가공 시 가공특성에 관한 연구

이종혁,박달근 충주대학교 2006 한국교통대학교 논문집 Vol.41 No.-

From the experimental study on lathe cutting work of Mg alloy, the characteristics such as Sr and SiC for maximum peak to valley roughness height, the third point height, ten-point hight. Experiments is roughness for sampling length determine of measuring length is 15mm. maximum peak to valley roughness height is Sr increased with most suitable cutting condition at 0.5% and SiC increased with most suitable cutting condition at 10%. The third point height is Sr increased with most suitable cutting condition at 0.5% and SiC increased with most suitable cutting condition at 10%. ten-point hight is Sr increased with most suitable cutting condition constant at 0.5% and SiC increased with most suitable cutting condition at 10%

變煥法에 의한 設計渴水量의 誘導

李淳赫,朴鐘國,孟昇辰 충북대학교 농업과학기술연구소 1994 農業科學硏究 Vol.11 No.2

Derivation of reasonable design low flows was attempted by comparative analysis of design low flows derived by Power and SMEMAX transformations for the normalization of skewed distribution in the four watershed of main river basins in Korea. The results were analyzed and summarized as follows. 1. Basic statistics of annual low flows for the selected watersheds were calculated by using Power and SMEMAX transformations. 2. Power transformation has found to be the best for the normalization of skewed distribution among others including Log, Squareroot and SMEMAX transformations. 3. Design low flows for the seleted watershed were derived by the Power and SMEMAX transformations. 4. Judging by the relative suitablities for the Power and SMEMAX transformations, it was found that design low flows using two methods are closer to the observed data within 10 years of the return period, and those of Power transformation can be acknowledged as a reasonable one in comparison with SMEMAX transformation over 10 years of the return period.

Gumbel-Chow 法에 의한 確率渴水量의 誘導 및 比較 分析

李淳赫,朴鐘國 충북대학교 농업과학기술연구소 1992 農業科學硏究 Vol.10 No.1

This study was carried out far getting reasonable design drought flows which can be contributed to the hydrologic design criterion of various hydraulic structures by comparative analysis between the results of Gumbel-Chew method and those of Weibull distribution which was studied by author already. Annual drought flows were used for the analysis of drought flows frequency at the three watersheds of Geum, Nag Dong and Yeong San river basins. The results were analyzed and summarized as follows. 1. Basic statistics were calculated for the analysis of Gumbel-Chow methed. 2. The frequency factors according to the return periods were evaluated to get probable drought flows for the research watersheds. 3. Probalble drought flows were derivated by the Gumbel-Chow method. 4. Comparing Gumbel-Chow method with Weibull distribution, it was found out that the former haute larger values than these of the latter within five years of return periods, and vice versa over the years of return periods at the research watersheds. 5. In comparison with the observed and the two kinds of results, probable drought flows by Weibull method were shown to be closer to the observed than

영어에 있어서 지시표현의 한정기술과 Deixis에 대하여

이종혁 공주교육대학교 초등연구원 1983 公州敎大論叢 Vol.19 No.-

I. 諸論 1 II. 限定記述 2 A. 指示的 使用과 屬性的 使用에 對하여 2 1. 指示的 경우의 Aspect에 대하여 4 2. 屬性的 경우의 Aspect에 대하여 6 B. 限定記述의 Truth와 存在 前提에 對하여 7 III. Deixis 8 A. 直示的 要素의 Demonstratives에 관하여 8 B. Debds와 Anaphola의 관계 9 C. 直示的 槪念의 區別에 관하여 10 1. Pure Deixis와 Injure Deixis 10 2. Primary Deixis와 Secondary Deixis 11 IV. 結論 11 참고문헌 13