침전법에 의한 알루미나 분말제조 Ⅲ. 소결체의 열적·기계적 특성

임헌진,이홍림,이형직,홍기곤 연세대학교 산업기술연구소 1992 논문집 Vol.24 No.1

A precipitation method was adopted in order to prepare high-tech Al₂O₃ceramics. Al₂(SO₄)₃·18H₂O was used as a starting materials and alumimum hydroxides were obtained by single precipitation method at the pH condition 7 and 11, using NH₄OH as a precipitation agent. Fine Al₂O₃powders were prepared at optimum calcination condition and were sintered at 1650℃ for 4 h in air. Microstructures and mechhanical properties of Al₂O₃ceramics were investigated. Doped MgO limited the grain growth of Al₂O₃and increased grain size homogeneity of Al₂O₃Flexural stregth values were 340∼430 MPa. Critical temperature difference?? was 175 K showing rapid strength degradation by thermal shock.

2차원 해석을 이용한 지하복합구조물 설계의 문제점 : 지하철 정거장을 중심으로

김형곤,조현영,정진환 釜山大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.52 No.-

본 연구에서는, 3차원 지하구조물이 2차원 뼈대조구조해석에 의해서 설계될 때의 문제점 들, 즉 갑작스런 단면의 변화, 개구부, 길이방향으로의 지반상태의 변화들이 검토 되어진다. 구조물들 3차원 해석에서 실제구조물과 가능한한 가장 근사하게 FEM에 의해 이상화되어진다. 본 연구로부터, 다음과 같은 두가지 결론을 내릴수 있다. 첫째, 개구부가 존재하는 곳에서는 보다 정확한 휨 모멘트분포를 얻기 위해 3차원이나 판이론에 의한 세부적인 해석이 수행되어져야 한다. 둘째, 건조수축, 수화열 그리고 힘의 분배에 대한 길이방향 보강을 결정하기 위해서는 더 세심한 검토가 필요하다. In this study, the problems when 3-D underground structures were designed by using 2-D plane frame structure analyses, such as sudden changes of sections, openings, and the variations of the ground conditions in the longitudinal directions, were investigated. The structures were idealized by FEM as close as possible to the real structures in 3-D. From this study, the authors conclude following two results. First, 3-D or detailed analysis with plate theory where openings exist must be carried out to obtain more accurate bending moment distribution. Second, a more refined investigation is needed to determine the longitudinal reinforcement due to shrinkage, the heat of hydration and the distribution of forces.

기니픽에서 Magnesium의 혈관 이완과 혈압 하강 효과

김정곤,강형섭,김진상 한국수의공중보건학회 2003 예방수의학회지 Vol.27 No.2

The present study evaluated the effects of various agents on magnesium sulfate (Mg^(2+))-induced relaxation in aorta and blood pressure lowering in anesthetized guinea pigs. Mg^(2+) inhibited phenylephrine (PE)- or 40 mM KC1-induced sustained contraction of endothelium-intact (+E) guinea pig aortic rings in concentration-dependent manner. In preparations preconstricted with PE or KC1, Mg^(2+)-induced concentration-dependent relaxations. In preparations preconstricted with PE or KCl, Mg^(2+)-induced relaxations were not affected by the removal of endothelium (-E) and by the pretreatment of aortic rings with NO synthase (NOS) inhibitors (L-NAME and LNNA), guanylate cyclase inhibitors (methylene blue and ODQ, adenylate cyclase inhibitor (MDL), K^(+) channel blockers (glibenclamide and tetrabutylammonium), nifedipine or ryanodine. However, Mg^(2+)-induced relaxations were inhibited by Na^(+)-Mg^(2+) exchange inhibitor (imipramine) or removal (or attenuation) of extracellular Ca^(2+) in +E aortic rings. PE-induced contraction was not inhibited by nifedipine. In addition, Mg^(2+)-induced relaxations were inhibited by phospholipase C inhibitor (NCDC) or inositol monophosphatase inhibitor (lithium), but not by protein kinase C inhibitor (staurosporine). In vi패 infusion of Mg^(2+), directly into the femoral veins of guinea pigs, elicited sustained decrease in arterial blood pressure. The Mg^(2+)-lowered blood pressure was attenuated by intravenous administration of imipramine or lithium, but not by methylene blue, indomethacin, tetrabutylammonium nifedipine, LNNA, L-NAME or saponin (as an endothelium removal agent). These results suggest that endothelium independent vasorelaxant effect of Mg^(2+) on aortic ring appear to play important roles on the antihypertensive action in guinea pig, most likely via the inhibitory action of Mg^(2+) on the intracellular C^(2+) involve in PLC-IP pathway and influx (through the Na^(+)-Mg^(2+) exchanger) into the cell in guinea pig aorta.

악성 거대 난소 점액성 종양 1예

신형도,박형진,김홍곤,한원철 圓光大學校 醫科學硏究所 1999 圓光醫科學 Vol.15 No.1

Mucinous tumor are cystic tumors with loculus lined with mucin-secreting epithelium constitute approximately 8-10% of primary epithelial ovarian tumors. Of all mucinous neoplasms, 75-85% are benign. It is often reach very large size particularly with the benign counterpart being reported on occasion to have exceed 100 lbs. Malignancy develops in 5-10% of benign mucinous cysts. About 15-20% of neoplasms are bilateral. We experienced a huge ovarian mucinous tumor of 155 ㎏. measured 42 × 30 × 28 ㎝ in size, and the volume of cystic contents was about 10 L in a nulligravida 36-year-old woman. Pathologic diagnosis was moderately differentiated mucinous cystadenocarcinoma of right ovary. So, we presented with a brief review of literatures.

계열화 및 전공코스제 운영방안

최병태,이형민,홍성준,정두진,김대곤 대구산업정보대학 2000 논문집 Vol.14 No.2

This paper is an attempt to propose our study that draw up a plan about faculty and major course to the Daegu Polytechnic College authorities. Our approach is a mixture of methods. It is systematic, in that it attempts to treat a college as a system. Through the second chapter, we examine the periodic, social, environmental, governmental, and economic context within which the College's developing effort must progress. Chapter three examines how the college systems actually design about faculty and major course. Thus, chapter four discusses how new faculty and major course participants attempt to compose a curriculum; chapter five accesses the institutions available in the College to distribute these designs. In conclusion, this paper presents that the College system would be better nine faculty; education and nurse·health field only be in administration unit, an information field be better divided into two parts: internet computer and information communication, and business and computer design faculty is established as intimate information. After all, the system will be characteristic in its information traits.

셀룰라 이동 통신 시스템에서 경로 손실 데이터베이스를 이용한 이동국의 위치와 속도 추정 방식

李相憲,鄭遇坤,崔炯辰 성균관대학교 1998 학술회의지원논문목록집 Vol.1998 No.-

차세대 셀룰라 이동통신 시스템은 기지국의 소형화와 서로 다른 크기의 기지국의 복합형태인 계층구조 셀룰라 형태를 가지게 되는데 이에 따른 시스템의 컨트롤은 이동국의 정확한 위치와 속도에 관한 추정을 전제로 한다[13]. 본 논문에서는 지금까지 연구되어온 이동국의 위치 추정 기법인 AOA(Angle of Arrival)와 TOA(Time of Arrival)및 TDOA(Time Difference of Arrival)의 방법을 설명하고 그 문제점을 분석하였고, 반사와 회절이 심하여 이동국의 위치 및 속도 추정이 어려운 마이크로셀 환경에서는 서비스 지역내 경로손실값의 이상 지역 데이터 베이스를 이용하여 이동국의 위치를 추정하는 방법을 제안하였다. 속도의 추정은 위치의 추정치로부터 시간에 대한 변화값으로 얻었다. 오차를 최소화하기 위하여 시스템의 Causality를 만족하는 범위 안에서 이동평균(Moving Average) 방법의 Smoothing을 적용하여 그 성능을 개선하였다. 또한 이산 지역 데이터 베이스의 탐색지역을 줄이는 방법을 제안함으로 시스템의 구현을 간단하게 할 수 있는 방안을 제시하였다. To achieve the required services in the next-generation cellular telephone systems, the size of the cell become smaller and/or is of mixed macrocells and microcells. To more efficient system control, we make use of the mobile position and velocity information, provided that the mobility information is relatively accurate. In this paper, we propose an improved version of path-loss measurement algorithm introduced in literature[11]. In microcellular structure with servere multipath fading, reflection and refraction make mobile position and velocity estimation very difficult. In the proposed method, the pre-recorded path-loss informations, called the discrete position data vase, are searched to estimate the position. Velocity estimation is obtained as a difference of the position values with respect to the time difference. Moving average is applied to smooth the estimated velocity and to reduce the error in the estimates. We also propose a method to simplify system implementation by reducing search area for discrete area datebaase.

마이크로-매크로 셀룰라 시스템을 위한 계층선정 기법분석

김장섭,이상헌,정우곤,최형진 成均館大學校 科學技術硏究所 1998 論文集 Vol.49 No.1

A control scheme to select the appropriate layer between macro- and microcell hierarchical structure is considered. With the assumption that the each mobile speed is known to the system. the algorithm determines the optimal velocity threshold by which the cell section performed. The optimal criterion is to minimize the Grade of Service(GOS), a service criterion in cellular telephone systems. Mobile station with faster speed relative to the determined optimal speed threshold are assigned to a macrocell, while slower moving terminals are assigned to the smaller cells, i,e.. microcells. For the evaluation purpose for the proposed scheme, two different evaluation perspectives are compared and the algorithm proves to work

계층구조 무선망 셀룰라 시스템에서 신호세기 측정을 이용한 이동국의 위치와 속도 추정에 관한 연구

이상헌,김장섭,정우곤,최형진 成均館大學校 科學技術硏究所 1998 論文集 Vol.49 No.1

Estimating the positron and velocity of mobile stations is an important issue tar hierarchical cellular systems as the efficient allocation of mobiles to macro or microcells depends on its position and velocity. rower measurement method is applied and discrete location path-loss information is used to estimate the position of the mobile. Velocity estimation is treated in the same way with the position estimation problem since the mobility is the movement in a unit time. Lowpass smoothing technique and moving average are applied. The results prove to enhance the performance of the system. The path-loss data used in the simulator 2D-tracing method. Direction of _Future research in the topics are presented.

개의 콜레스테롤 담석 증례

전혜영,박성환,한재익,이숙진,김근형,정동우,나기정 충북대학교 동물의학연구소 2006 Journal of Biomedical and Translational Research Vol.7 No.1

본문참조

A rare case of metastatic cholangiocarcinoma associated with humoral hypercalcemia of malignancy

Hyung-Jin Park · Sang-Gon Park · Su-Jin Hong · Hee-Jeong Lee · Woo-Jin Lee · Jun-Won Seo 조선대학교 의학연구원 2011 The Medical Journal of Chosun University Vol.36 No.2

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