Silica nanoparticle-carried surface fabricated by directional melt crystallization

지상원,이종휘 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

Manufacturing certain surface morphology has been challenging in the polymer industry. Patterned morphology assigned some functional properties, hydrophobicity or engineered friction, etc, to polymer surfaces. However, these strength couldn’t often overcome polymer’s weakness, low electrical conductivity, magnetic conductivity, etc. Herein, we made inorganic-nanoparticle-loaded polymer surfaces by directional melt crystallization (DMC) of solvents. DMC is a simple technique to make uniformly porous morphology on polymer surfaces. Silica nanoparticle and polycarbonate (PC) were chosen as an inorganic nanoparticle and a polymer substrate. 1,4-Dioxane was used as a solvent to disperse silica nanoparticles and dissolve PC surfaces. By decreasing temperature of PC surface right before treating, the resulting surface morphology showed a decrease in pore size. The effects of carried silica were optimized at contact angle and sliding angle. Through this technique, embedding other inorganic materials in polymer sheets can be simply done.

Investigation into the Effects of Mosapride on Motility of Guinea Pig Stomach, Ileum, and Colon

지상원,박효진,조준식,임중현,이상인 연세대학교의과대학 2003 Yonsei medical journal Vol.44 No.4

Mosapride citrate (Mosapride) is a new prokinetic agent that enhances the gastrointestinal (GI) motility by stimulation of 5-HT4 receptors. This agent stimulates acetylcholine release from enteric cholinergic neurons in the GI wall. It was reported in several studies that mosapride selectively enhanced the upper, but not lower, GI motor activity. However, in these studies other 5-HT4 receptor agonists exerted stimulating effects on the motility of the colon. Moreover, it is well known that the receptors of 5-HT4 are also located in the colon. The purpose of this study was to estimate the effect of mosapride on the motility of the stomach, ileum and colon in the guinea pig and to investigate whether or not mosapride influenced the colonic motility. Mosapride significantly increased the amplitude of the contraction waves in the guinea pig stomach by electrical stimulation. In addition, it significantly increased the number of peaks, the area under the curve and the propagation velocity of the peristaltic contraction of the guinea pig ileum in a concentration dependent fashion. Mosapride also significantly shortened the transit time of the guinea pig colon. Accordingly, we concluded that mosapride exerted prokinetic effect on the entire GI tract of the guinea pig. Based on the possibility of similar results in humans, we suggest the potential use of mosapride for lower GI motor disorders such as constipation and upper GI motor disorders such as gastroesophageal reflex disease or gastroparesis.

좁은 수로 항법에 관한 대법원 판결 평석

지상원 한국항해항만학회 2008 한국항해항만학회 학술대회논문집 Vol.2008 No.추계

대법원 2004추65(2005. 9.28. 선고) 판결에 의하면 좁은 수로 항법은 좁은 수로에서 선박의 충돌을 효과적으로 예방하기 위하여 적용되는 특별항법으로서 조종제한선이라고 하여 적용이 배제되지 아니하므로 좁은 수로에서는 상대 선박으로부터 진로 우선권을 양보 받았다는 등 다른 특별한 사정이 없는 한, 좁은 수로 항법을 지키는 선박에 대한 진로 우선권이 보장되는 것이 아니다 라고 하고 있다. 그러나 이와 같은 좁은 수로 항법을 좁게 적용하는 문제를 가지고 있기 때문에 이 논문은 올바른 해석 원칙을 제시한 것이다.

선원 재해보상제도의 개선 방안에 관한 고찰

지상원 한국해사법학회 2009 해사법연구 Vol.21 No.3

Fabrication of inorganic nano-particles loaded polycarbonate surface by directional melt crystallization

지상원,이종휘 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

Surface modification has been an important engineering area in the processing of polymeric materials. Herein, we developed a novel surface engineering tool based on directional melt crystallization (DMC). DMC has been developed to prepare porous materials of ceramics and polymers. We applied the same technique only to the surface of a polymeric material, polycarbonate (PC). Solution of 1,4-dioxane and loading materials, which were well dispersed, dissolved PC surface until crystallization started. Inorganic particles can be uniformly loaded on the surface of PC sheet with DMC. With this method, other inorganic particles with certain purposes are expected to be simply loaded on PC sheet by DMC. Also this technique can be applied to other polymer sheets with using their proper solvents and of course other inorganic particles.

CFRP Grid가 인장재로 사용된 콘크리트 보의 휨거동

지상원,홍기남,연영모,한민철,정병은 한국복합신소재구조학회 2023 복합신소재구조학회논문집 Vol.14 No.2

본 논문은 CFRP Grid를 철근 대체재로 사용하기 위해 수행된 실험적 및 해석적 연구를 보고한다. CFRP Grid가 철근대신 적용된 콘크리트 보의 휨거동을 평가하기 위해 총 5개의 콘크리트 실험체가 제작되었다. 실험변수로 CFRP Grid의 보강 겹수, 피복두께가 고려되었다. 3점 휨실험을 통해 모든 실험체는 휨파괴됨을 확인하였다. 특히, 2겹과 3겹의 CFRP 그리드를 갖는실험체는 CFRP Grid의 급작스런 파단으로 파괴되었다. 초기 균열하중은 CFRP Grid 보강 겹 수가 증가할수록 증가하였다. 반면초기균열하중에 대한 피복두께의 영향은 명확하게 나타나지 않았다. 극한하중은 CFRP Grid의 보강 겹수 및 피복두께의 영향이명확하게 나타났다. CFRP Grid로 보강된 콘크리트 보의 휨거동을 예측하기 위한 유한요소해석 결과는 실험체들의 균열양상 및파괴모드를 유사하게 예측하였다. 특히, 극한하중, 극한하중에 대응하는 처짐, CFRP Grid의 변형률을 매우 유사하게 예측하는것으로 나타났다. 따라서 본 연구에서 제안된 해석모델은 CFRP Grid가 철근 대체제로 사용된 콘크리트 보의 휨거동을 예측하기위해 효과적으로 사용될 수 있을 것으로 판단된다.

미세먼지 저감용 필터설치 구조물의 차량충돌 안전성 검토

지상원,홍기남,김혁중,최유승 한국복합신소재구조학회 2020 복합신소재구조학회논문집 Vol.11 No.4

This paper reports on the performance evaluation process and results for road structures designed to reduce fine dust at bus stops. First, collision analysis for the target structure was performed using LS-DYNA, a finite element analysis program. Structural analysis was performed under various conditions considering the vehicle speed and the collision location as analysis variables. The performance of the target structure and safety performance of the vehicle after the collision were evaluated using structural results. From the results of the analysis, it was confirmed by the amount of damage to the concrete that the structural performance of the structure and the safety performance of the vehicle after the collision deteriorated as the collision speed increased and the collision location approached the front of structure. In addition, through the analysis of the behavior of the vehicle after the collision, it was predicted that if a continuous curb was installed in the facility, it would be expected to secure safety by preventing the vehicle from leaving the driving road. Finally, it was confirmed that the target structure secured sufficient safety performance up to 40 km/h, which is larger than the target collision speed of 25km/h considered in the design. 본 논문은 버스정류장 미세먼지 저감을 위해 설계된 도로시설물의 성능평가 과정 및 결과를 보고한다. 먼저, 유한요소해석 프로그램인 LS-DYNA를 이용하여 대상 구조물에 대한 충돌해석이 수행되었다. 해석변수로 차량의 속도와 충돌 위치를고려한 다양한 조건에서의 구조해석이 진행되었다. 대상 시설물의 성능은 이 결과를 이용하여 구조적 성능과 충돌 후 차량의안전성능이 평가되었다. 해석결과로부터 충돌속도가 증가하고 충돌위치가 전면으로 갈수록 시설물의 구조성능과 차량의 충돌후 안전성능이 저하되는 것이 콘크리트의 손상량을 통해 확인되었다. 더불어 충돌 후 차량의 거동에 대한 분석을 통해 시설물에 연속되는 연석이 설치되면 차량의 이탈을 방지해 안전성능을 확보하는 것으로 예측되었다. 최종적으로, 대상 시설물은 설계시 고려된 목표 충돌속도 25km/h보다 더 큰 40km/h까지 충분한 안전성능을 확보하고 있다는 것이 확인되었다.

Fabrication of surface-embedded Inorganic particles/polycarbonate composites

지상원,이종휘 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

해상교통법상 통항항해배제에 관한 해석론적 고찰

지상원 한국항해항만학회 1995 한국항해학회지 Vol.19 No.3

There is a vessel which shall not impede the passage of any other vessel in the COLREGS 1972. But the issue was raised that the words of "not to impede" were vague. Therefore, IMO adopted new paragraph (f) to be added to Rule 8 that a vessel which is required not to impede the passage of another vessel is not relieved of this obligation if approaching the vessel so as to involve risk of collision. It means that the ship which is obliged not to impede should contributes to avoid collision and to the safe passage of the other vessel. Also it results that the application of Collision Rules should be changed. But until now, it seems that the mariners are not familiar with this subject. This paper, therefore, aims to define the meaning of "not to impede" and clarify it's legal concept so as to adequate application of the Collision Rules for the collision avoidance at sea.on avoidance at sea.

비만한 성인에서 당대사에 따른 성장호르몬-결합단백농도 : 체지방 분포, 성호르몬, 인슐린 분비능 및 성장호르몬-인슐린양 성장인자-1 축과의 연관성 Relationship to Body fat Distribution Sex Hormones, Insulin and GH-Insulin-Like Growth Factor (IGF)-1 Axis

지상원,허갑범,이현철,임승길,김경래,송영득,남수연,김경욱,윤세정 대한내분비학회 1999 Endocrinology and metabolism Vol.14 No.3

Background: As GHBP is believed to be derived from proteolytic cleavage of the extracellular domain of the GH receptor and may be regarded as an intrinsic part of the GH-IGF-1 axis, an effect of body composition on circulating GHBP levels may be expected. We investigated GHBP variations in obesity with varying glucose tolerance and its relationship to body fat distribution, sex hormones, insulin secretion, and the GH-IGF-1 axis. Methods: Bioelectrical impedence for measurement of total body fat and computed tomography for visceral fat and subcutaneous fat at umbilicus level were performed in 69 obese Koreans and 21 lean Koreans. Insulin secretion in response to an oral glucose tolerance test (OGTT) and a GH stimulation test by L-dopa, growth hormone-binding protein (GHBP), insulin-like growth factor (IGF)-1 and sex hormones (estrone, estradiol, total and free testosterone) were measured. Results: Obese type 2 DM group had the highest GHBP levels and the most visceral fat amount. GHBP levels were most strongly correlated with the ratio of visceral fat area to body weight (VWR) above other parameters (r=0.725, p$lt;0.001). Insulin- and free fatty acid-area under the curve (AUC) during OGTT and IGF-1 level were also positively correlated with GHBP levels (r=0.474, p$lt;0.005; r=0.572, p$lt;0.005; r=0.453, p$lt;0.005). GH-AUC to L-dopa stimulation test was negatively correlated with GHBP levels (r=0.432, p$lt;0.005). The GHBP level was slightly higher in females than in male in the same glucose tolerance category. In males, total and free testosterone levels were negatively correlated with GHBP levels (r=-0.516, p$lt;0.001;r=-0.653, p$lt;0.001). Stepwise multiple linear regression analysis showed that VWR, FFA-and insulin-AUC significantly contributed to the variability of GHBP (r=0.58). Conclusion: We demonstrated that 1) visceral fat amount was mainly determined GHBP levels in obese subjects with varying glucose tolerance; 2) hyperglycemia per se did not influence GHBP level, whereas insulin and FFA could play a role in regulation of GHBP level. 3) The constant concentration of IGF-1 despite GH hyposecretion suggests that increased GHBP level retlect GHBP hypersensitivity in order to compensate for decreased GH secretion in obesity; 5) the lower level of GHBP in males might be explained at least in part by a suppressive effect of androgen (J Kor Soc Endocrinol 14:531-540, 1999).