• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.206-210
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• 2005

As design trends has changed to have flexible aft hull structure, increased power output and stiffer shafting system, owners and classification societies have more concerned about shaft alignment. In the shaft alignment analysis, there are many uncertainties which are related in propeller generated force, bearing stiffness, crank shaft model and etc. in this study, it is focused on the effect of crankshaft model by comparing between equivalent model and actual crankshaft model.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 춘계 학술대회논문집
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• pp.134-137
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• 2007

Aero-Heating phenomenon is one of the severe problems occurring in high speed missile flight. in the high speed flight, not only stagnation point but also aft body parts encounter high temperature related structural problems. But the phenomenon is not easy to predict accurately because unsteady calculation according to a flight trajectory is needed, and takes much time. In this Paper, a fast and precise scheme is introduced, which calculates heat flow and temperature by simple pressure field prediction on a missile.

• 한국정밀공학회지
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• 제17권6호
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• pp.135-142
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• 2000

In this paper, 3-dimensional numerical model of an escalator is developed to study the vibration characteristics. This proposed model is able to consider the elastic deformation of the frame during transient dynamic analysis. Deformation modes which are used to calculate the elastic deformation are selected from the FE model analysis. Because low frequency vibration is very important to the ride quality of fore/aft direction, low frequency deformation modes of the frame below 20Hz are considered. To show validity of this dynamics model, longitudinal acceleration of a step is compared with test data in frequency domain. Then robust design technique is applied to determine important design factors and improve ride quality with small number of experiments.

• 한국항공운항학회지
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• 제14권2호
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• pp.9-16
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• 2006

FAA AC120-40B Level D flight dynamics model for T-50 Full Mission Trainer was successfully developed. Since AC120-40B Level D requires the quantitative validation tests for simulation model compared with flight test data, T-50 flight test data for each validation test item was gathered, and also automatic test environments which include AFT (Automatic Fidelity Tester) and STA (Simulation Test Analyzer) were developed. The final test results after the iterative test-tuning processes were all within the tolerances specified in AC120-40B Level D. Qualification Test Guide, QTG contains the detail test processes and results.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.66-75
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• 1997

Sound transmission from the luggage comparment into the car cabin is important in the viewpoint if exhaust and road noises of passenger cars. In this paper, acoustic modal coupling between passenger and luggage compartments through loudspeaker holes at parcel shelf is dealt with for a sedan type passenger car with rigid rear seat. For these purposes, a half-scaled model car is tested and computed by the indirect BEM. Predicted acoustic transfer functions are compared with experimental ones and they agree reasonably well. It is found that the fore-aft resonance frequencies of the passenger cavity in the absence of coupling holes are tend to shift to higher frequencies when the luggage compartment is coupled to the passenger cavity.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.256-273
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• 2019

Nowadays interceptors have been widely used in a vast range of high-speed crafts. In this study, the results of interceptor adeptness experiments made in Istanbul Technical University's Towing Tank are unveiled. The model was tested through three transverse locations of interceptors with six different deployment depths. For three locations, the interceptor was positioned transverse on the aft; close to chine, in the middle and close to the keel. The fourth interceptor was a full length of 13.00% LWL. The results show a significant drag reduction in benefits of 1.50%-11.30% for Fn 0.58-1.19 and the trim reduction was observed in between 1.60 and $4.70^{\circ}$. Besides, one of the most significant conclusions indicates that the effect of the interceptor decreases from keel to chine for the same blade deployment heights so the blades should be controlled separately at least in three parts from keel to chine area, if operable.

• 한국해양환경ㆍ에너지학회지
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• 제4권1호
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• pp.38-46
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• 2001

조류 중에 설치한 이중 유벽의 유효성을 검증하기 위하여 유벽 전후 및 유벽사이에서의 유적(oil droplet)의 거동을 실험적 및 수치적으로 연구하였다. 이 연구에는 단일 유벽의 경우 유벽의 유연성이 포유성능에 미치는 영향도 포함되었다. 실험은 유적의 밀도와 근사한 구형의 고체입자가 전방 유벽의 상류 한 지점에서 방류되었을 때 그 궤적을 추적하는 것이 내용이었다. 입자는 방류되었을 때 유동장의 상태에 따라 자유표면으로 부상하거나, 유벽에 충돌 또는 유벽하로 빠져나가는 현상을 나타내게 된다. 본 논문에는 이러한 유적의 이동 경위를 해석함으로써, 이러한 유적의 유적이 운동을 시작하는 영역이 어딘가에 따라 전방유벽하로 기름이 누출될 것인지 아닌지를 판단할 수 있는 방법과 전후 유벽의 흘수의 차 그리고 수심이 이중유벽의 포유성능에 미치는 영향을 해석할 수 있는 방법을 제시하였다.

• 자원리싸이클링
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• 제28권1호
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• pp.32-39
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• 2019

본 연구에서는 석고의 형태로 황산염이 혼입된 알칼리 활성 슬래그의 수화반응에 대해, 깁스 최소화 에너지 개념을 이용한 반응계산 결과가 계산 조건에 따라 어떻게 달라지는지에 대해 확인하였다. 계산을 위한 변수로는 황화물의 고려 여부, AFt/AFm 상의 생성가능성 여부, 대기 중 산소의 반응기여 여부 등을 검토하였다. 계산결과, 실제 위의 다양한 조건의 변화에도 불구하고 공극량, 화학수축과 같이 이후 배합의 성능에 영향을 미칠 수 있을 만한 값 들은 크게 차이가 발생하지 않았는데, 이 변수들에 의한 변화폭은 물결합재비에 의한 변화폭에 비해 월등히 작은 값이었다. 생성되는 물질들의 종류 및 양은 일부 초기조건 설정에 따라 변화할 수 있으나, 가장 주요한 수화물인 C-(N-)A-S-H의 생성량에는 별다른 영향을 미치지 않았다.

• The Korean Journal of Physiology and Pharmacology
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• 제26권5호
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• pp.347-355
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• 2022

Abdominal aortic aneurysm (AAA) is a life-threatening disorder worldwide. Fibroblast growth factor 21 (FGF21) was shown to display a high level in the plasma of patients with AAA; however, its detailed functions underlying AAA pathogenesis are unclear. An in vitro AAA model was established in human aortic vascular smooth muscle cells (HASMCs) by angiotensin II (Ang-II) stimulation. Cell counting kit-8, wound healing, and Transwell assays were utilized for measuring cell proliferation and migration. RT-qPCR was used for detecting mRNA expression of FGF21 and activating transcription factor 4 (ATF4). Western blotting was utilized for assessing protein levels of FGF21, ATF4, and markers for the contractile phenotype of HASMCs. ChIP and luciferase reporter assays were implemented for identifying the binding relation between AFT4 and FGF21 promoters. FGF21 and ATF4 were both upregulated in Ang-II-treated HASMCs. Knocking down FGF21 attenuated Ang-II-induced proliferation, migration, and phenotype switch of HASMCs. ATF4 activated FGF21 transcription by binding to its promoter. FGF21 overexpression reversed AFT4 silencing-mediated inhibition of cell proliferation, migration, and phenotype switch. ATF4 transcriptionally upregulates FGF21 to promote the proliferation, migration, and phenotype switch of Ang-II-treated HASMCs.

• 한국항만경제학회지
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• 제39권1호
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• pp.47-63
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• 2023

스마트 항만 및 항만 자동화에 수직 배치형 컨테이너 터미널을 적용하여 운영하는 사례가 늘고 있다. 본 연구는 수평 배치형과 수직 배치형 컨테이너 터미널에서의 본선작업 시간을 분석함으로써 각 터미널간 생산성을 비교하고, 향후 수직 배치형 컨테이너 터미널의 운영 효율성 증대 방안을 제시하고자 한다. 이를 위해 각각을 대표하는 터미널을 선정하여, 2018년부터 2022년까지 최근 5년 선석배정현황 데이터를 수집하였으며, 모수적 생존분석 기법인 가속실패시간모형(Accelerated Failure Time, AFT)을 활용하여 분석을 실시하였다. C/C 작업 조건이 '동일하다'는 가정 하에서, 수직 배치형 컨테이너 터미널에서의 본선 작업 생산성이 보다 좋은 것으로 나타났으며, 코로나19 기간에는 생산성이 감소한 결과를 나타냈다. 작업량이 많은 선박의 경우와 유럽 선사의 선박의 경우, 본선작업 시간이 감소하는 걸 알 수 있다. 적정 C/C의 투입 및 효율적 운영, 장비들 간 원활한 운영, shifting 작업은 증가, C/C를 포함한 하역 장비들의 준비시간 감소 및 고장/사고 최소화 등 수직 형태 컨테이너 터미널의 생산성을 높이기 위한 방안을 제시하였다.