• 한국수산과학회지
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• 제26권6호
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• pp.538-548
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• 1993

한국 동해 연안역 해수순환 및 수온분포에 대한 바람응력의 효과에 관하여 검토하였다. 동해상의 바람응력은 국립수산진흥원 정선관측 바람자료 및 일본기상청 Buoy No. 6에서의 10년간($1978{\sim}1987$)의 약 5,100개의 바람 관측자료를 사용하여 계산하였다. 여름과 겨울의 계절풍의 전환에 따른 에크만 수송의 변화가 대한해협에서의 대마난류 수송량에 미치는 영향을 정량적으로 평가하였다. 특히 동해에서의 평균적인 바람응력의 회전성(wind stress curl) 값이 음이 되는 사실에서 울릉도 근해의 난수층의 형성에 부분적으로 도움이 됨을 알았다. 한편, 동해 난수층의 분포를 단순화된 3층 경계면모델을 적용하여 설명하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.656-663
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• 2010

본 연구에서는 K.Terzaghi의 유효응력이론을 인용하여 압밀기반의 안전하중 산출 과정과 결과를 제시하였다. 일반적인 강도를 평가하기 위하여 이용된 J.I.Solovyov의 순간강도 이론에 기초를 두어, 제시한 방법은 포화된 연약점토지반에서 도로의 유지보수 뿐 아니라 축조 과정에 안전하중의 계산 적용이 가능하다. 실제로 편리한 표준 압밀 drain test에서 정의된 점착력, 내부 마찰각과 같은 강도정수를 가진 유효응력은 실제적 적용을 고려하기 위하여 산출된다.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.200.1-200.1
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• 2003

The purpose of this study is to examine whether an brain to blood efflux system for taurine is present on the blood-brain barrier (BBB) or not and this efflux transport system is regulated by CNS cell damage with oxidative stress agent such as diethyl maleate (DEM) or tumor necrosis factor-a (TNF-${\alpha}$), by using the brain efflux index (BEI) method. The brain efflux index value is defined as the relative amount of test compound efflux from cerebrum compared with that of a reference compound, [$\^$14/C] carboxyinulin, which has limited BBB permeability. (omitted)

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.823-824
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• 2012

• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1740-1747
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• 2017

To investigate allowable peak cladding temperature and hoop stress for maintenance of cladding integrity during interim-dry storage and subsequent transport, zirconium alloy cladding tubes were hydrogen-charged to generate 250 ppm and 500 ppm hydrogen contents, simulating spent nuclear fuel degradation. The hydrogen-charged specimens were heated to four peak temperatures of $250^{\circ}C$, $300^{\circ}C$, $350^{\circ}C$, and $400^{\circ}C$, and then cooled to room temperature at cooling rates of $0.3^{\circ}C/min$ under three tensile hoop stresses of 80 MPa, 100 MPa, and 120 MPa. The cool-down specimens showed that high peak heat-up temperature led to lower hydrogen content and that larger tensile hoop stress generated larger radial hydride fraction and consequently lower plastic elongation. Based on these out-of-pile cladding tube test results only, it may be said that peak cladding temperature should be limited to a level < $250^{\circ}C$, regardless of the cladding hoop stress, to ensure cladding integrity during interim-dry storage and subsequent transport.

• Steel and Composite Structures
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• 제39권4호
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• pp.453-469
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• 2021

The cracking at the transverse diaphragm cutout is one of the most severe fatigue failures threatening orthotropic steel decks (OSDs), whose mechanisms and crack treatment techniques have not been fully studied. In this paper, full-scale experiments were first performed to investigate the fatigue performance of polished cutouts involving the effect of an artificial geometrical defect. Following this, comparative experimental testing for defective cutouts strengthened with carbon fiber-reinforced polymer (CFRP) was carried out. Numerical finite element analysis was also performed to verify and explain the experimental observations. Results show that the combinative effect of the wheel load and thermal residual stress constitutes the external driving force for the fatigue cracking of the cutout. Initial geometrical defects are confirmed as a critical factor affecting the fatigue cracking. The principal stress 6 mm away from the free edge of the cutout can be adopted as the nominal stress of the cutout during fatigue evaluation, and the fatigue resistance of polished cutouts is higher than Grade A in AASHTO specification. The bonded CFRP system is highly effective in extending the fatigue life of the defective cutouts. The present study provides some new insights into the fatigue evaluation and repair of OSDs.

• 물과 미래
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• 제22권2호
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• pp.191-200
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• 1989

소류사의 입자이동속도와 소류사농도의 곱으로 소류사량을 계산할 수 있는 한 방법이 제시되었다. 본 연구에서 사립의 평균이동속도는 하상부근의 유속난류성분의 출현빈도가 정규분포 한다고 가정하고, 입자이동속도를 소류력의 함수와 하상부근의 평균유속의 곱으로 나타내었다. 소류사에 유효하게 작용하는 소류력을 구하기 위해서 Engelund가 제시한 식을 사용하여 유효마찰속도를 구하였으며 Engelund가 제시한 식의 적합성을 간접적으로 검증했다. 소류사농도를 구하기 위해서 호전·도상의 식을 사용하였다. 실험자료는 타 연구자들의 식과 비교되었으며 타 연구자들의 식과 비슷한 경향을 나타내었다. 소류력이 비교적 작은 경우를 제외하고 제시된 식에서 계산된 결과와 타연구자들의 자료는 잘 일치하였다.

• 한국해양공학회지
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• 제32권4호
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• pp.244-252
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• 2018

This paper provides quantification of the effects of the turbulence model and grid refinement on the analysis of tip vortex flows by using the RANS(Reynolds averaged Navier-Stokes) method. Numerical simulations of the tip vortex flows of the NACA $66_2$-415 elliptic hydrofoil were conducted, and two turbulence models for RANS closure were tested, i.e., the Realizable $k-{\varepsilon}$ model and the Reynolds stress transport model. Numerical results were compared with available experimental data, and it was shown that the data for the Reynolds stress transport model that were computed on the finest grid system had better agreement in reproducing the development and propagation of the tip vortex. The Realizable $k-{\varepsilon}$ model overestimated the turbulence level in the vortex core and showed a diffusive behavior of the tip vortex. The tip vortex cavitation on the hydrofoil and its trajectory also showed good agreement between the current numerical results that were obtained using the Reynolds stress transport model and the results observed in the experiment.

• Biomolecules & Therapeutics
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• 제16권1호
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• pp.14-20
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• 2008

In the present study, we examined how the transport of choline is regulated at the blood-brain barrier (BBB) under the central nervous system (CNS) cellular damages by oxidative stress using a conditionally immortalized rat brain capillary endothelial cells (TR-BBB), in vitro the BBB model. It was also tested whether the choline uptake is influenced by membrane potential, extracellular pH, protonophore (FCCP) and amiloride in TR-BBB cells. In result, $[^3H]choline$ uptake was inhibited by FCCP and dependent on extracellular pH. The treatment of TR-BBB cells with 20 ng/mL tumor necrosis $factor-{\alpha}$ $(TNF-{\alpha})$, 10 ng/mL lipopolysaccharide (LPS), 100 ${\mu}M$ diethyl maleate (DEM) and 100 ${\mu}M$ glutamate resulted in 3.0-fold, 2.6-fold, 1.8-fold and 2.0-fold increases of $[^3H]choline$ uptake at the respective peak time, respectively. In contrast, hydrogen peroxide and raffinose did not show any significant effects on choline uptake. In addition, choline efflux was significantly inhibited by $TNF-{\alpha}$, LPS and DEM producing cell damage states. In conclusion, the influx and efflux transport system for choline existed in TR-BBB cell line and this process was affected by several oxidative stress inducing agents.

• 한국해안해양공학회지
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• 제6권4호
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• pp.364-374
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• 1994

본 연구에서는 순압모델을 이용하여 대마난류(Tsushima Warm Current)의 분기기작 및 계절별 분기위치의 변화에 바람이 미치는 영향을 살펴보았다. 모델 격자간격은 위도와 경로방향 모두 0.25$^{\circ}$로 하였고 해수표면에 적용한 계절별 바람응력은 Hellerman and Rosenstein(1983)의 바람을 이용하였다. 모델결과에 의하면 대마난류는 북풍계열의 바람이 강한 동계(10월-3월)에는 일론 큐슈 남서쪽 대륙사면에서 쿠로시오로부터 직접 분기되어 형성되며, 하계(4월-9월)에는 대만해협(Taiwan Strait)을 통해 유입된 대만난류가 대마난류의 기원으로 나타난다. 쿠로시오는 동계에 최대 수송량을 가지며 하계에 최소를 보이고, 대만난류(Taiwan Current)의 수송량은 이러한 쿠로시오와 약 160도의 위상차를 갖는다. 대마난류의 수송량 변화는 쿠로시오의 변화와 120$^{\circ}$의 위상차(약 4개월)를 가질 때 잘 일치한다.