• 설비공학논문집
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• 제14권1호
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• pp.46-54
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• 2002

To investigate the design effects of a heat exchanger on a tube type, a tube circuit and a fin pitch, an experimental study on the heat transfer characteristics of finned- tube evaporators was performed. The refrigerant was R-22. A refrigerant loop was established to measure the heat transfer rate, the air heat transfer coefficient. The experimental results showed that the heat transfer characteristics of the evaporators were affected by the design parameters. And the heat transfer rate of the slit fin was better about 25%, compared to those of the louver fin. In the present experimental range, the heat transfer performance with the straight tube circuit was more remarkable than that of the zigzag tube circuit, as seen from temperature variations of the evaporator exit. $\jmath$-factor on the tube type, the tube circuit and the fin pinch decreased, as increasing Reynolds number.

• 대한기계학회논문집B
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• 제34권2호
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• pp.179-184
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• 2010

스트레이트 휜 히트 싱크가 장착된 공간에 팁 클리어런스(tip clearance)와 바이패스 유동이 열성능에 미치는 영향을 실험적으로 규명하고자 한다. 수평 및 수직 방향으로의 바이패스 유동에 의한 열성능 평가는 열식 질량 유량계(MFC)와 소형 풍동으로 이루어진다. 팁 클리어런스와 바이패스 유동에 의한 히트 싱크의 열성능은 열저항을 통하여 평가한다. 실험 결과, 스트레이트 휜 히트 싱크의 열저항은 팁 클리어런스가 증가함에 따라 점진적으로 증가하며, 유동 가이드 장치는 바이패스 유동을 감소하는 역할을 한다. 본 연구에서는 동일 유량 조건에서 히트 싱크의 입구에서 유동 가이드 장치까지의 거리에 따라 스트레이트 휜 히트 싱크의 최적값이 존재함을 확인하였다. 히트 싱크로 유입되는 유량이 증가함에 따라 유동 가이드 장치에 의한 열성능 개선 정도는 증가한다.

• 오토저널
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• 제6권1호
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• pp.36-45
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• 1984

The conventional heat transfer analysis methods based on the one-dimensional theory are not adequate to be applied for the purpose of finned surface design because the two-dimensional effects in fact are induced within the supporting wall by the presence of the finnes. In this study, the two-dimensional heat transfer of a straight fin assembly is analyzed by using the integral method. It is shown that all the effects of the system parameters i.e., the heat transfer parameters and geometrical parameters, on both the total heat transfer rate and the surface temperature effectiveness can be seen from the present analysis. The optimum combinations of these parameters for the design of finned surfaces may be estimated.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제9권1호
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• pp.91-98
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• 2005

The straight rectangular fin is analyzed using the one-dimensional analytic method and the finite difference method. For the finite difference method, the numbers of nodes vary from 20 to 100. The relative errors of heat loss and temperature between the analytic method and the finite difference method are represented as a function of Biot Number and dimensionless fin length. One of the results shows that the relative error between the analytic method and the finite difference method decreases as the numbers of nodes for finite difference method increase.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.5.1-5.1
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• 2005

• 한국어류학회지
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• 제26권3호
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• pp.235-238
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• 2014

갈치과에 속하는 Tentoriceps cristatus 1개체(표준체장 619.0 mm)가 제주도 주변해역에서 저층트롤로 처음으로 채집되었다. 이종은 머리의 외곽이 둥근 점(유사종 분장어는 직선을 이룸), 배지느러미는 등지느러미 12번째 기조 밑에 위치하는 점(유사종 분장어는 15~17번째 기조 밑에 위치), 등지느러미 기조수가 V, 131개, 가슴지느러미 기조수가 11개, 배지느러미가 비늘형태로 변형된 점, 그리고 뒷지느러미의 극조수가 2개(2번째 극조는 비늘모양으로 변형됨)인 점이 특징이다. 본 종의 속명과 종명은 "투구갈치속"과 "투구갈치"로 각각 명명하였다.

• Ocean Science Journal
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• 제42권4호
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• pp.231-240
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• 2007

Three marine fish species are recorded for the first time from Korean waters: a molid (Ranzania laevis, 1 specimen, 279.8 mm SL) and bramid (Pterycombus petersii, 3 specimens, 95.3-214.0 mm SL) collected from a large purse seine off Jeju Island, in the southern sea of Korea, and a carangid (Carangoides dinema, 1 specimen, 194.5 mm SL) from a set net in coastal waters off Busan, in the southeastern sea of korea. R. laevis is characterized by a wedge-shaped body and truncated clavus; P. petersii by the dorsal fin origin above or behind the posterior margin of eye, and dorsal and anal fins depressible; and C. dinema by a row of black blotches along the second dorsal fin base, the curved part of the lateral line longer than straight part, and 18 and 16 dorsal and anal fin rays, respectively. New Korean names are proposed for all three species.

• 설비공학논문집
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• 제15권2호
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• pp.132-136
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• 2003

For the study of performance evaluation on different shape heat exchangers that have the same energy consumption in a refrigerator, we make performance evaluation coefficient (PEC) which can distinguish performance of different shape heat exchangers. The results were reported in order to compare with for the dry frosting and wet frosting test as various definition of PECs. Results showed that PEC of dry frosting test is higher than that of wet frosting test because attached water droplet increases pressure drop of air-side then this decreases performance of heat exchanger.

• 대한조선학회논문집
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• 제59권6호
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• pp.423-431
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• 2022

In this paper, the results of Planar Motion Mechanism (PMM) test for a 1/15 scaled model of the MARIN Joubert BB2 submarine is dealt with to derive the maneuvering coefficients for surface condition. For the depth of surface navigation, the top of the sail was exposed 0.46 m above the water surface in the model scale, and it corresponds to 6.9 m in the full scale. The resistance and self-propulsion tests were conducted, and the model's self-propulsion point was obtained for 1.328 m/s, which corresponded to 10 knots in the full scale. The maneuvering tests were performed at the model's self-propulsion point, and the maneuvering coefficients were obtained. Based on the maneuvering coefficients, a turning simulation was performed for starboard 30 degree of stern fins. The straight-line stability and control effectiveness in the horizontal plane were analyzed using the maneuvering coefficients and compared with the appropriate range. For the analysis of the neutral fin angle of the X-type stern fin, the stern fin test with drift angles was carried out. As a result, the flow straightening effect at lower and upper parts of the stern fin was discussed.

• 한국어류학회지
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• 제20권2호
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• pp.129-132
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• 2008

전갱이과에 속하는 Carangoides oblongus 1개체(표준체장 133.8 mm)가 제주연안의 정치망에서 처음으로 채집되었다. 이 종은 형태적으로 C. dinema와 유사하지만 옆줄의 직선부가 곡선부보다 길고, 미병부의 옆줄 위 모비늘 수, 등지느러미 연조 수 및 뒷지느러미 연조 수에서 차이를 나타내었으며, 이 미기록종의 신한국명을 "채찍유전갱이"라고 명명하였다.