切削加工에서 다듬질面의 粗度에 미치는 影響에 關한 硏究

李鐘赫 忠州大學校 1993 한국교통대학교 논문집 Vol.28 No.-

I have studied on the effects of applied tools wear and intensity of illumination according to each condition which were changed cutting speed, feed and cutting depth for using carbide tools, carbon steel for machine structural use. I have abtained conclusion as followings; 1. I have confirmed again on the effects of applied illumination surface according to cutting speed, feed and cutting depth when work materials are in need of finishing precisely face. 2. It I have less made feed motion intensity of illumination was increased, the more cutting work of time is long the more chattering happened a primary of factor. 3. Even if cutting depth was a number increased, it was not accepted on the effects of applied intensity of illumination.

"半圓形 Notch를 가진 低炭素鋼의 破壞擧動에 關한 硏究"

李鍾赫 忠州大學校 1989 한국교통대학교 논문집 Vol.23 No.-

Resulting from fatigue breaking behavier in use of structure and mechanics by mechanical industry thesedays, the economic loss to result from crack occurrence has been brought about too much loss of lives. In this paper, for the sake of the point at issue solution I have studied on the absorption energy at cracking occurance, stress enlarge coefficient K₁, enlongation quantity by early deformation and maximum load and elongation in the process of generating plastic deformation to which material break resulting from tensile load at the test piece with half round notch.

섬유강화 고분자 복합판의 기계적 성질에 미치는 섬유길이와 섬유함유율의 영향

이상동,김혁,허업,최종대,이동기 조선대학교 에너지.자원신기술연구소 1997 에너지·자원신기술연구소 논문지 Vol.19 No.2

This paper describes effect of chopped strand length fiber content and moisture absorption on mechanical properties of fiber-reinforced polymeric composites. It was extrusion compounded long fiber-reinforced polypropylene containing 20, 30 and 50 percent and short fiber-reinforced ABS and PAS containing 30 percent b37 the weight of glass fiber. The test methods of ASTM D638, D3410-87 and D79OM are applied for tensile, compressive and bending tests respectively. The results show that, in the case of 0.2% moisture absorption, the residual strength decreases dramatically.

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

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.

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.

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.

급성 심근경색증을 동반한 혈전성 혈소판 감소성 자반증 1예

이태희,김진혁,김완중,박지영,강흥선,조정휘,김권삼,송정상,배종화 대한순환기학회 2003 Korean Circulation Journal Vol.33 No.11

뇌자도 측정을 위한 저잡음 Nb SQUID 센서의 설계 및 제작

이용호,권혁찬,김진목,이상길,임청무,박용기,박종철 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

We report on the design, fabrication and performances of a low-noise Nb SQUID sensor for neuromagnetic measurements. The main features of the developed sensor are i) large flux-to-voltage transfer, making the SQUID readout electronics simple, and ii) use of the integrated planar pickup coil to eliminate the environmental magnetic field noises. The magnetic field noise of the developed SQUID sensor is below 5 fT/√Hz at 100 Hz, which is low enough to be used in neuromagnetic measurements.

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.