• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1009-1014
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• 2007

To improve passenger safety, seatbelt systems with pre-tensioner that tightens seatbelt webbing using explosives just before collision are widely adopted. Even though seatbelt must not be unlatched without passenger's operation, release of a buckle due to explosion of pre-tensioner takes place in some situations resulting in serious injury to passengers. To prevent the unintended unlocking, a pendulum like part called anti-g mass is attached to the buckle to block displacement of release button. In this study, the unlocking conditions of anti-g buckle when pre-tensioner explodes has been theoretically investigated. Through multibody model of the seatbelt system incorporating every detailed part of the buckle, dynamic analysis of the seatbelt system with pre-tensioner has been performed including the driver's body model that interacts with seatbelt system. The simulations results has been validated through actual sled test with driver dummy and the seatbelt system.

• Journal of the Korean Wood Science and Technology
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• 제30권3호
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• pp.18-25
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• 2002

Research to discuss the fire performance of materials requires tools for measuring their burning characteristics and validated fire growth models to predict fire behavior of the materials under specific tire scenarios using the measured properties as input for the models. In this study, burning characteristics such as time to ignition, weight loss rate, flame spread, heat release rate, total heat evolved, and effective heat of combustion for four types of wood-based materials were evaluated using the cone calorimeter and inclined panel tests. Time to ignition was affected by not only surface condition and specific gravity of the tested materials but also the type and magnitude of heat source. Results of weight loss rate, measured by inclined panel tests, indicated that heat transfer from the contacted flame used as the heat source into the inner part of the specimen was inversely proportional to specific gravity of material. Flame spread was closely related with ignition time at the near part of burning zone. Under constant and severe external heat flux, there was little difference in weight loss rate and total heat evolved between four types of wood-based panels. More applied heat flux caused by longer ignition time induced a higher first peak value of heat release rate. Burning characteristics data measured in this study can be used effectively as input for fire growth models to predict the fire behavior of materials under specific fire scenarios.

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7549-7554
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• 2015

본 이 연구의 목적은 부유 기술을 이용하여 제형이 위에 더 오래도록 머무르면서 약물을 지속적으로 방출하는 이중정을 개발하는 것이다. 실험방법으로는 메트포르민을 주 약물로 선정하였는데, 그 이유는 메트포르민은 주로 소장 상부에서만 흡수되는 좁은 흡수 영역 대를 가지고 있는 점, 용해도가 매우 높아 약물 방출을 조절하는 것이 쉽지 않은 점 등 때문이다. 정제의 부유를 위한 가스를 생성하는 부분과 약물의 방출을 조절하는 부분의 간섭을 최소화하기 위해 이중정 타정 기를 사용해 이중정으로 제조하였으며, 정제의 모양, 질량 및 경도를 측정하였고, 부유정의 중요한 요소인 부유 촉발시간과 부유유지 시간을 평가하였다. 또, 약물의 방출 조절을 평가하기 위해 용출시험을 시행하였으며, 그 결과를 시판되고 있는 메트포르민 서방성 제제인 Glucopharge XR$^{(R)}$과 비교평가 하였다. 그 결과, 부유 촉발제인 $NaHCO_3$ 및 약물 방출 조절제인 hydroxypropyl methylcellulose (HPMC)의 사용량에 따라 13초의 부유 촉발시간, 10시간 이상의 부유 유지시간 및 시판 제제와 매우 유사한 약물 방출 거동을 확인할 수 있었다 ($f_2$: 89.6). 결론적으로 메트포르민을 함유한 위 체류 이중정을 성공적으로 개발할 수 있었으며, 그로 인해 메트포르민의 치료효과도 극대화 할 수 있을 것으로 예상된다.

• 한국자동차공학회논문집
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• 제4권5호
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• pp.187-196
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• 1996

In this study, 3-dimensional finite element model of a diesel engine cylinder head was made to accomplish heat transfer analysis and also thermal stress and deformation analysis. Heat release analysis and Nusselt-Reynolds correlations were applied to determine the convective boundary conditions which are required for heat transfer analysis to calculate temperature distribution. Thermal stress distribution was also investigated from heat transfer analysis results. Steady state temperature and heat flux were measured by using K-type thermocouples and then compared with numerical results to give a guarantee for the propriety of numerical analyses.

• Biomolecules & Therapeutics
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• 제13권4호
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• pp.251-255
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• 2005

In the present study, we tried to investigate whether protein kinase C (PKC) activator, phorbol 12-Myristate 13-Acetate (PMA), and PKC inhibitors, $G\"{o}-6976$, Ro-31-8220 and rottlerin significantly affect basal mucin relesed from cultured airway goblet cells. Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled with $^3H$-glucosamine for 24 hr and chased for 30 min in the presence of each agent to assess the effects on $^3H$-mucin release. The results were as follows: (1) PMA increased mucin release from cultured HTSE cells, during 30 min of treatment period; (2) However, $G\"{o}-6976$, Ro-31-8220 and rottlerin did not significantly affect mucin release, during 30 min of treatment period. This finding suggests, at least in part, that PKC might playa minor role in the signaling pathways involved in basal - physiological or constitutive - mucin release from airway goblet cells, although further studies are needed.

• Composites Research
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• 제27권2호
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• pp.72-76
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• 2014

본 연구에서는 알루미늄 합금으로 된 경사진 이중외팔보의 충돌에 대해서 각각의 충격속도 2.5m/s, 7.5m/s, 12.5 m/s 별로 실험과 시뮬레이션 해석을 하였다. 접착부분에 발생하는 에너지 해방율과 응력을 평가하여 알루미늄 합금의 기계적 특성을 고찰하였다. 실험상에서는 접착 부분에서 에너지 해방율의 값이 높은 것으로 나타났다. 이는 실험에서 시험편이 분리된 후에도 접착력이 유지되는 특성 때문인 것으로 사료된다. 충격속도와 상관없이 균열이 진전하다가 접착된 부분의 끝에서 높은 응력을 발생하기 때문에 최대 등가응력은 마지막 단계에서는 올라간다. 본 연구에서의 실험 및 해석결과들은 충돌에 의한 균열 진전을 방지할 수 있는 복합재료에 대한 안전설계의 개발에 필요한 자료로 사료된다.

• Journal of Ginseng Research
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• 제14권2호
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• pp.122-125
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• 1990

Ethylene was released from leaf and fruit but root of Panax ginseng. Root callus showed higher ethylene release (ER) than fruit ER increased with leaf senesence. Fruit during ripening showed decreasing ER in the order of green stage, early stage of reddening and fully ripened stage. between leaves from the plant with fruits in different stages of ripening showed similar trend of fruit in ER but it was about 10 times higher in leaves than in fruits. Leaves of P. quinquefolius showed about 200 times higher ER than that of P ginseng on 22 July Fruits from the plant treated with ethephon showed higher ER after 109 days. Forty-five day-old seedlings grown with various growth regulators showed a significant decrease of stem length and significant increase of ER only in Uniconazole (0.1 ppm) and H-9 (0.0, 5 ppm) solution.

• Nuclear Engineering and Technology
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• 제32권5호
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• pp.425-432
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• 2000

It has been an essential part for the safety assessment of nuclear power plants to understand various phenomena associated with the molten core-concrete interaction(MCCI) under severe accidents. In this study, the severe accident analysis code MELCOR was used to simulate the MCCI experiments such as SWISS and SURC test series which had been performed in Sandia National Laboratories(SNL). The calculation results were compared with corresponding experimental data such as melt temperature, concrete ablation distance, gas generation rate, and aerosol release rate. Good agreements were observed between MELCOR calculation and experimental data. The melt pool was sustained within the range of high temperature and the concrete ablation occurred continuously. The gas generation and aerosol release were under the influence of melt temperature and overlying water pool, respectively.

• Advances in materials Research
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• 제9권2호
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• pp.109-114
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• 2020

The purpose of this study was to observe the trend of compounds release from acrylic resin oral prosthesis when used for drug delivery as well as a restoration. In this study, 10 specimens of heat-cured polymethylmethacrylate material were prepared and loaded with methylene blue biological stain. The specimens were then submerged in vials with 5 ml distilled water for 24 hours. The extraction procedure continued for 4 days, each day the specimens were immersed in another 5 ml distilled water vial. All extracted solutions were analyzed by visible light spectroscopy for absorbance comparison. The statistical results showed that the absorbance values were significantly different in the first day of extraction than the following days. However, there was no statistical difference among the 2^nd, 3^rd and 4^th days of extraction. Biological stain loading to acrylic resin at the mixing stage, and then after extraction in distilled water, showed a burst release during the first day followed by a constant release during the following few days.

• Structural Engineering and Mechanics
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• 제50권5호
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• pp.665-677
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• 2014

A numerical method, using a special mixed finite element associated with the virtual crack extension technique, has been developed to evaluate the energy release rate for kinking cracks. The element is two dimensional 7-node mixed finite element with 5 displacement nodes and 2 stress nodes. The mixed finite element ensures the continuity of stress and displacement vectors on the coherent part and the free edge effect. This element has been formulated starting from a parent element in a natural plane with the aim to model different types of cracks with various orientations. Example problems with kinking cracks in a homogeneous material and bimaterial are presented to assess the computational accuracies.