풍화에 따른 퇴적암의 강도 변화

배우석,이봉직,오세욱,이종규 한국산업안전학회 2003 한국안전학회지 Vol.18 No.1

The failure of rock slopes were influenced by weathering, which causes change in the shear strength. The weathering is also directly related to slaking and swelling characteristics. In the paper, the core of diameter 10㎝ was obtained by digging on rock slope of Kong-ju in Korea and the EDX (Energy Dispersive X-ray spectrometer) analysis was carried out to verified element of chief rock-forming minerals. Uniaxial compression tests, slaking tests, and point load test are performed to study engineering characteristics of conglomerate and red shale. As a results of slaking test, slaking index of conglomerate indicate range of 85.11-99.58 and shale indicate 58.37-99.23.Therefore, it is recognized that the resistance of shale to weathering decreases in shallow depth and it greatly influences the strength of rock. The result of uniaxial compression test and point load test show that the strength of sedimentary such as conglomerate and red shale has an influence on both weathering and saturation.

신경회로망을 이용한 SRM의 토오크맥동 저감제어

안진우,오석규 慶星大學校 1998 論文集 Vol.19 No.1

This paper proposes a control scheme reducing the torque ripple of SRM using ANN(Artificial Neural Network). The torque of SRM depends on phase current and the rate of inductance variation. But the latter is nonlinearly changed according to phase current, which makes a difficulty to control the instantaneous torque. Therefore learned inductance of SRM using ANN that is known to treat nonlinear system recently, is used to predict instantaneous torque and to reduce torque ripple in SR drives.

Al₂O₃-40% iO₂ 용사층의 연구 (Ⅱ) : 마멸기구 모델링 modelling of wear mechanism

김우섭,오명석,채영훈 영남이공대학 1998 論文集 Vol.27 No.-

The wear behaviors of Al₂O₃-40%TiO₂ deposited on Al-alloy of casting(ASTM A356) by plasma spray against SiC ball have been investigated experimentally. Friction and wear tests are carried out at room temperature. The thickness of Al₂O₃-40%TiO₂ coatings indicated the existence of the optimal coating thickness. The columnar grain of coating will be fractured to achieve the critical stress. It is suggested that the mismatch of thermal expansion of substrate and coating play an important role in wear performance. Tensile and compressive of coating under thermo-mechanical stress may be occurred by the mismatch between thermal expansion of substrate and coating. This crack propagation above interface is observed in SEM.

CFRP 판재의 섬유방향에 따른 절삭성 평가

신봉철,하석재,강민형,권오양,조명우 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-

In recent, the CFRP(Carbon Fiber Reinforced Plastics) composite has been widely used because it has light-weight and high mechanical strength. Therefore, CFRP composite is applied to variable industrial areas such as aerospace, automobiles, sporting goods, ships and so on. Generally, CFRP composite has been used in the industrial field by mechanical cutting processes. In this research, the CFRP composite specimen are laminated by 64plies with orientation angles such as 0°, 45°, 90° and [0°/±45°/90°]4S. The results are analyzed with cutting force and cutting surface.

전자공학교육과 실험교과내용에 관한 연구

홍봉식,김태균,오승엽,김환우,권오석 충남대학교 공업교육연구소 1983 論文集 Vol.6 No.2(A)

The currenty offered experiment courses are completely reconsidered and reconfigured. The whole subjects are divided into 10 seperate courses, each of which should represent either basic or advanced stages of differing fields of the electronic engineering. It has been aimed that the courses form an elaborate hierachy so that they are minimally redundant but linked to one another in their fringes. Also, it has been pursued that the new courses should not fall obsolete in at last next five years exploring the maximum possibilities of the currently available equipments.

고밀도 집적화를 위한 Inverse Chebyshev MOSFET-C 필터 설계

金東龍,崔碩佑,吳成根 全北大學校 1992 論文集 Vol.34 No.-

Continuous-time integrated filters, implemented in MOS VLSI technology, have been receiving considerable attention. In this paper, a continuous-time fifth order active RC Inverse Chebyshev filter is designed using cascade method which each block can be tunable. The resistors of an active RC network are replaced by a linear resistor using NMOS depletion transistors operated in the triode region. This MOSFET linear resistors which have simple structure can be adjusted by control voltage. And we have designed CMOS operational amplifier for fabrication. The Inverse Chebyshev MOSFET-C filter characteristics are simulated by PSPICE program.

소아에서 발생한 골수이형성 증후군 2례

홍성진,윤석중,김성우,조형구,오명호,김기혁,이인성 건국대학교 의과학연구소 1996 건국의과학학술지 Vol.5 No.-

Myelodysplastic syndrome(MDS) is a group of acquired conditions characterized by progressive bone marrow failure associated with normocellular or hypercellular bone marrow that cannot be attributed to nutritional deficiency, chronic infection, or other chronic systemic illness, and cannot be reversed by the successful treatment of those conditions. Whereas the cases of secondary MDS occur at all ages, primary MDS is essentially a disease of elderly, though no age group is exempt and predomonant in men. The MDS is fundamentally clonal disorders at the level of the haemopoietic totipotent stem cell. Clinically, they are characterized by varing degrees of peripheral cytopenia(s) with morphological and functional abnormalities of blood elements. We have experienced two unrelated pediatric cases, who showed pancytopenia on admission and the characteristic marrow findings of MDS. The first case, a 12 months-old girl, showed increased reticulin with abnormal localization of immature precursor cells(ALIP) in her bone marrow, in addition to dysplastic features such as bi-and multi-nucleation of late normoblasts and internuclear bridging. She also showed 22% of blasts in her bone marrow cells thus classified in the category of RAEB-t after FAB classification. Also found were a chromosomal abnormality namely 46 XX t(14q21q), which was an unusual one. Her family brought her home and, 4 month later, she deceased. The second case, a 12 year-old boy, showed pancytopenia with Pseudo-Pelger-Huet anomaly in neutrophils but no blasts in the peripheral blood. Bone marrow of this case also showed the picture of dyserythropoiesis with binuclearity, internuclear bridging, nuclear fragments, multinuclearity of late normoblasts, in addition to megaloblastoid change in the normoblasts and increased mitosis in granulocytic series. No chromosomal abnormality was found. Classified as RA after FAB classification of MDS. Showed good response to conservative management for anemia for more than one year.

2단 간헐 포기조의 포기/비포기 시간비에 따른 영양염류 제거특성

김홍태,신석우,오상화,권성현 한국환경과학회 2004 한국환경과학회지 Vol.13 No.7

This study was conducted to remove organics and nutrients using 2 stage intermittent aeration reactor. First reactor, using suspended microbial growth in intermittent aeration instead of anaerobic reactor in the typical BNR process, used minimum carbon source to release P. and it was possible to reduce ammonia loading going to second reactor. In the second reactor, using moving media intermittent aeration, it was effective to reduce nitrate in non-aeration time by attached microorganisms having long retention time. In aeration time, nitrification and P uptake were taken place simultaneously. From the experiment, two major results were as follows. First, the removal of organics was more than 90%, and optimum aeration/non-aeration time ratio for organic removal was corresponded with aeration/non-aeration time ratio for nitrogen removal. Second, in the first reactor, optimum aeration/non-aeration time ratio was 15/75 (min.) because it was necessary to maintain 75 min. of non-aeration time to suppress of impediment of return nitrate and to lead release of phosphate. In the second reactor, optimum aeration/non-aeration time ratio was 45/90 (min.).

電子産業의 要求측면에서 본 工業高等學校 電子系列學科 敎育改善을 爲한 基礎硏究

羅聲雄,林在鳳,沈殷燮,金煥宇,權五錫 충남대학교 공업교육연구소 1982 論文集 Vol.5 No.1

This thesis aims at finding the present abilities of the graduates from Electronic Departments of Technical High schools, their present value to the Electronic Industry, and the required qualifications. The following suggestions are proposed to improve the education of Technical High schools, and to meet the needs of the future. -Such basic subjects as English, Korean(including Chinese letters), Mathematics are to be emphasized in the curricula. -Basic theory in major subjects should be broadened rather than stressing experiments and practice in specific trades. -Major subjects are to include more wide and general theories than those of the present.

상악골과 하악골에 각각 발병한 섬유성이형성증 치험 2례

박노부,문선혜,남동석,이용오,서연호,김우철 啓明大學校 醫科大學 1993 계명의대학술지 Vol.12 No.4

The fibrous dysplasia of bone is a benign, slow growing, perplexing tumor of bone that replace the normal bone by the fibrous tissue composed of collagen fibers, fibroblasts and containing variable amount of mineralization. A fibrous dysplasia tends to occur more frequently in women than men and to be seen more in maxilla than mandible. This tumor may obliterate maxillary sinus and extend to the infraorbital area, zygoma but may not obliterate the nasal cavity. And this tumor may expand the cortical plate of the mandible, mandibular cannal and may involve to the condylar head so that facial asymmetry is provoked. Ideal treatment of the fibrous dysplasia is the surgical intervention. Because it is a diffuse lesion the complete excision is difficult, so the conservative osseous contouring is recommended. We treated two patients, one was a 18-year-old female with fibrous dysplasia in maxilla involving zygoma, infraorbital rim and maxillary sinus, the other was a 32-year-old female with fibrous dysplasia in mandibular posterior area. We operated the former by conservative surgery with osseous contouring and the latter by reconstructive surgery with titanium mesh and plate after mandibular resection under general anesthesia. We obtained successful functional and esthetic results and no recurrence was seen in two years postoperative follow up.