p-Anisaldehyde가 조골세포 분화에 미치는 영향

김경민 ․ 이도원 ․ 김현준 ․ 김아랑 ․ 장원구 대구대학교 산업기술연구소 2018 産業技術硏究 Vol.29 No.2

p-Anisaldehyde is a natural fragrance extracted from Pimpinella anisum L., and used as a preservative. This study examined the effect of p-anisaldehyde on osteoblast differentiation. First, cytotoxicity tests were carried out after examining the concentrations that did not show toxicity to the cells. The expression of osteoblast differentiation marker gene was confirmed by RT-PCR and was not effective in the treatment with p-anisaldehyde alone. However, p-anisaldehyde decreased the expression levels of inhibitor of differentiation-1 (Id1), distalless related homeobox (Dlx5), and runt-related transcription factor 2 (Runx2), which are osteogenic differentiation marker genes, which are increased in osteogenic condition. alkaline phosphatase (ALP) activity was also confirmed by ALP staining that p-anisaldehyde reduced ALP activity. These results show that p-anisaldehyde is effective in reducing osteoblast differentiation.

하천형상에 따른 유출특성의 변화에 관한 수치적 연구

조현경 영남이공대학 1998 論文集 Vol.27 No.-

This study is two goals. One is the exploration of a variation of runoff characteristics for single and looped channel networks. The other is the exploration of a variation of runoff characteristics for the influence of some channel and tloodplain hydraulic and geometric properties on the frequency distribution of peak flood flow rates as flood waves propagate downstream. For this purpose, a one-dimensional flood routing model is used to a numerical simulation. In this paper the finite difference method is applied to the solution of the Saint-Venant equations. Results show that the peak discharge and peak time in the looped channel becomes less than single channel and it influences a variation of downstream runoff characterist-ics for some channel and floodplain hydraulic and geometric properties.

인공모래 부산물 재활용 방안

김경남,신대용,이현종 강원대학교 부설 석재복합신소재 제품연구센터 2002 석재연 논문집 Vol.7 No.-

인공모래 제조시 부산물로 발생하는 석분슬러지에 의한 환경문제와 폐기되는 자원의 활용문제를 해결하기 위하여 석분슬러지와 점토 및 폐유리분말을 이용하여 900∼1,100℃로 소성하여 세라믹스 건자재를 제조하였다. 석분 슬러지는 평균입경 16.3㎛, 비표면적 0.42㎡/g, 화학조성은 CaO 46.43wt%, SiO_2, MgO 와 Al_2O_3가 7.83 wt% , 6.17 wt% 및 3.13 wt%이며, 주결정상은 calcite (CaCO_3)와 dolomite (CaMg(CO_3)_2)로서 약 800℃에서 CaCO_3나 CaMg(CO_3)_2의 열분해에 의한 32.52wt% 의 강열감량을 나타내었다. 석분슬러지와 점토를 이용한 시편(No. 1, 4, 7, 10 및 13)은 점토의 첨가량과 소성온도가 증가함에 따라 시편의 부피비중 및 압축강도는 증가하였으나 기공률과 흡수율은 감소하여 No. 1, 4, 및 7 시편은 부피비중 1.78∼1.98, 기공률 6.4∼12.5%, 흡수율 10.3∼12.7%, 압축강도 264∼370kgf/㎠을 나타내었다. 폐유리분말을 첨가한 시편(No. 2, 5, 6, 8, 9, 10 및 12)의 부피비중과 압축강도는 1.91∼2.63 및 213∼895kgf/㎠로서 폐유리분말의 첨가가 시편의 소결성과 압축강도의 향상에 기여하여 세라믹스 건자재로 사용이 가능하였다. The utilization of waste stone powder sludge produced secondarily from artificial sand plants of Ssangyoung resource development (Co.) and general waste, as was classified, became very important to solve the environmental problem and waste materials recycle. In the chemical composition of stone powder sludge, the amount of CaO was 46.43wt%, SiO_2, MgO and Al_2O_3 were 7.83 wt% 6.17 wt% and 3.13 wt%, respectively. The mean average particle size was 16.3㎛ and specific surface area was 0.42㎡/g. Main crystal phases were calcite (CaCO_3) and dolomite (CaMg(CO_3)_2) and ignition loss was 32.52wt% because of decomposition of CaCO_3 or CaMg(CO_3)_2. Specimens were fabricated by mixing the waste stone powder sludge, low-grade clay, waste glass powder and sintering at 900∼1,100℃ for 2 hours. The density and compressive strength of specimen increased with increasing the sintering temperature and the amount of clay. The specimen showed the bulk density of 1.78∼1.98, porosity of 6.4∼12.5%, water absorption 10.3∼12.7% and compressive strength of 264∼370 kgf/㎠. Those of the specimen heated at 1,050℃ increased with increasing the added amount of waste glass powder, bulk density was 1.91∼2.63 and compressive strength was 213∼895 kgf/㎠. Therefore, the waste stone powder sludge can be used as a constructional materials.

개수로 합류점 부근에서의 흐름특성에 관한 연구

조현경,이순탁 嶺南大學校 環境問題硏究所 1996 環境硏究 Vol.16 No.1

요약문 본 연구는 개수로 합류접 부근에서의 지류유입에 따른 주하도의 흐름 특성의 변화를 산정 하는데 그 목적을 두고 있다. 또한 유입방향에 따른 주하도에서의 수심과 유속의 변화를 해석하였으며, 이를 위해서 합류부의 협각 30°, 60° 및 90°에 대해서 지류 유입량을 변환시키면서 시뮬레션을 수행하였다. 그 결과 주하도와 지류의 합류각이 커짐에 따라 상?하류의 유량비 (Q1/Q3)에 대해서 속도비 (V1/V3) 는 증가하고 수심비(H1/H3)는 감소함을 알 수 있었다. Abstract This study aims at the computation of flow characteristics of main channel for tributary inflow in the vicinity of open channel junctions. And this study was analyzed the variation of flow depth and velocity in main channel for inflow direction. For this purpose, simulation are carried out for variations of 30°, 60° and 90°angle and tributary inflow at junction. Results show that velocity ratio (V1/V3) increases and flow depth ratio (H1/H3) decreases for discharge ratio (Q1/Q3) of upstream and downstream when angle increases in junction.

Budd-Chiari 증후군 : 1례 보고 A Case Report

김승현,오연희,이현경,이성우,서정욱 동국대학교 경주대학 1997 東國論集 Vol.16 No.1

하대정맥의 막성폐쇄로 인한 Budd-Chiari 증후군은 비교적 드문 질환으로 알려져 있다. 저자들은 우상복부 동통을 주소로 내원한 환자에게 방사선학적 검사와 임상적으로 확진된 하대정맥의 막성폐쇄에 의한 Budd-Chiari 증후군 1례를 경험하였기에 문헌고찰과 함께 보고 하고자한다. The Budd-Chiari syndrome is a rare, often fatal illness resulting from hepatic venous outflow occlusion. It occurs secondary to intrinsic vascular thrombosis, tumor invasion, or rarely a congenital web. We report a case of primary Budd-Chiari syndrome with membranous obstruction of inferior vena cava, with a brief review of literature.

고유량 고효율 혈액투석막 재사용의 임상경험

조현경,김승정,임병국,정혁준,최영일,마경애,신규태,김흥수,김도헌 대한신장학회 2001 대한신장학회잡지 Vol.20 No.3

탄소섬유 적층혼성부재의 계면수 변화에 따른 축 압궤 특성

서현경,박준우,양용준,황우채,양인영 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

알루미늄과 CFRP는 대표적인 경량화 재료이다. 알루미늄 부재는 안정적인 소성 변형에 의해 에너지를 흡수하며, CFRP 부재는 비강성과 비강도가 우수하고 불안정한 취성파괴로 인해 에너지를 흡수한다. 이러한 각각 알루미늄과 CFRP 부재의 압궤 특성을 기초로 두 재 료의 결합에 의해 서로의 장점에 대한 시너지 효과를 얻기 위해 혼성구조부재를 제작하였다. 본 연구에서는 알루미늄 부재의 외측을 CFRP로 강화시킨 혼성구조부채를 제작하여 CFRP의 계면수 변화에 따른 축 방향 준정적 압궤실험을 행하여 사각 및 원형 단변 모형의 혼성구조부재의 압궤 특성을 조사하였다. 실험 결과 혼성구조부재는 내부의 알루미늄 부재의 연성 성질 때문에 CFRP 부재의 불안정한 취성 파괴를 보완하여 비교적 안정적인 압궤 모드를 보였다. 하지만 혼성구조부재는 계면수 변화에 대해 에너지 흡수성과 압궤 모드는 별다른 영향을 보이지 않았다. The aluminum or CFRP is representative of light-weight materials. The aluminum tubes absorb energy by stable plastic deformation and the CFRP tubes absorbs energy by unstable brittle failure with higher specific strength and stiffness. Based on the respective collapse characteristics of aluminum and CFRP tubes, the aluminum CFRP compound tubes were manufactured to get a synergy effect when the aluminum CFRP tubes were combined with the advantages of each tube. This paper is to investigate the collapse characteristics of square or circular shaped aluminum CFRP compound tubes subjected to quasi-static axial collapse tests which were conducted by changing the stacking conditions. Test results showed that the collapse of the aluminum CFRP compound tubes complemented unstable brittle failure of the CFRP tube due to the ductile characteristics of the inner aluminum tube. It turned out that interlaminar numbers of aluminum CFRP compound tubes have no influence on the energy absorption and collapse modes of the tubes.

낙동강유역의 중소하천에 대한 계획하폭의 결정에 관한 연구

조현경,이순탁 영남대학교 지역발전연구소 1997 새마을지역개발연구 Vol.20 No.-

This study aims at the determination of the design width for small stream in Nakdong river. For this study, it was chosen Naesung-stream which was located in the upstream of Nakdong river. In general the stream morphological characteristics of river basin has a very close correlation with the hydrological and hydraulic characteristics of the basin. So this study was derived a relationship between river width and discharge, basin area, river length. This study was suggested a river width formula for small streams in Nakdong river. As the result of analysis, it showed that these formula were very applicable.

개수로 분류지점에서의 흐름특성에 대한 수치적 연구

조현경 영남이공대학 산업기술연구소 2001 産業技術硏究 Vol.13 No.-

This study aims at the computation of a variation of flow characteristics of main channel for tributary outflow in open channels. Arid this study was analyzed the variation of flow depth and velocity in main channel for outflow direction. For this purpose, simulation are carried out for variations of 30°,60°,and 90°,degree and tributary outflow at junction using a numerical method. Results show that velocity ratio(v₂/v₁) decreases and flow depth ratio(h₂/h₁) increases for discharge ratio(Q₂/Q₁) of upstream and downstream when degree increases in junction.

산지유역 수문자료의 Chaos적 특성에 관한 연구

조현경 영남이공대학 산업기술연구소 2002 産業技術硏究 Vol.14 No.-

In this study, the correlation dimension and the largest Lyapunov exponent are used to diagnose whether some daily rainfall and stream flow data series are chaotic or not. And the time delay embedding method used to reconstruct an attractor from a time series. The analysis of daily rainfall and stream flow data series indicates the presence of some chaos.