• International Journal of Air-Conditioning and Refrigeration
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• 제15권3호
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• pp.85-100
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• 2007

This study presents a short overview of the researches in connection to the fin-and-tube heat exchangers with and without the influence of dehumidification. Contents of this review article include the data reduction method, performance data, updated correlations, and the influence of hydrophilic coating for various enhanced fin patterns. This study emphasizes on the experimental researches. Performance of both sensible cooling and dehumidifying conditions are reported in this review article.

• 한국어류학회지
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• 제25권3호
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• pp.169-172
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• 2013

A malformation of the anal fin in longfin trevally, Carangoides armatus, is described and compared with normal specimens. The fish specimen is clearly shown anal fin deformity with missing of 3 spines and 6 rays. The remaining eleven anal fin rays are shorter than those in the normal specimen. The causative factors of this anomaly were discussed.

• Journal of Mechanical Science and Technology
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• 제15권11호
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• pp.1541-1547
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• 2001

The non-dimensional fin length for optimum heat loss from a thermally asymmetric rectangular fin is represented as a function of the ratio of the bottom surface Biot number to the top surface Biot number, fin tip surface Biot number and the non-dimensional fin width. Optimum heat loss is taken as 98% of the maximum heat loss. For this analysis, three dimensional separation of variables method is used. Also, the relation between the ratio of the bottom surface Biot number to the top surface Biot number and the ratio of the right surface Biot number to the left surface Biot number is presented.

• 설비공학논문집
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• 제10권4호
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• pp.411-422
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• 1998

In this study, experiments were carried out to provide nucleate pool boiling heat transfer data for a plain tube and 4 different low fin tubes employing 2 refrigerant mixtures of R410A, R407C, and 12 pure fluids. Low fin tubes were machined on a 19.05mm nominal outside diameter copper block according to the manufacturer's low fin tube specifications. Cartridge heaters were used to generate uniform heat flux on the tubes. For all refrigerants, heat flux varied from 10㎾/$\m^2$ to 80㎾/$\m^2$. It is found that heat transfer coefficients(HTCs) of high vapor pressure refrigerants are usually higher than those of low pressure fluids. On the other hand, the fin effect was more prominent with low pressure refrigerants than with high pressure ones. Optimum fin density as well as the increase in heat transfer coefficient with the increase in fin density were found to be strongly fluid dependent. HTCs of Rl23, a low pressure alternative refrigerant, were similar to those of Rll while HTCs of R134a, an intermediate pressure alternative refrigerant, were roughly 20% higher than those of Rl2. Finally, HTCs of R32, R125, R143a, and R410A were all higher than those of R22 by 30~50%.

• 설비공학논문집
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• 제12권5호
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• pp.494-501
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• 2000

Effectiveness of a 3-pass plate finned-tube heat exchanger is calculated using heat exchangelet method by changing the shape of fin and the arrangement of tubes. The alternative refrigerant R134a is taken in this study. Conduction between neighboring tubes along the fin is taken into account in addition to convection between the fin and the surrounding air. Governing equations are obtained by using energy balance in a small control volume containing a tube and fins. They are numerically solved following the tube. Effect of tube-to-tube conduction is investigated in single-phase and two-phase flows with various fin shapes and arrangements of tubes. Improvement of effectiveness by fin perforation is studied too. The results shows that perforating fins, increasing the number of tubes, and increasing the distance between neighboring tubes at the same fin area enhance the effectiveness.

• 대한기계학회논문집B
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• 제29권9호
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• pp.1032-1041
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• 2005

This study is performed to investigate the heat transfer characteristics of heat exchanger according to the arrangement of fins as well as fin configuration by using the four times enlarged model. Friction factor, Colburn j factor and goodness factors are compared to each other to estimate performance of each case for 4 different kinds of fins, which are plain, single side slit, double side slit and louver fin. Results show that heat transfer would be altered by fin arrangement and that friction loss is more affected by fin configurations than by the fin arrangements. In particular, heat transfer depends more on the shape of front row than that of rear row. The heat transfer rate of combined fin arrangement increases a lot more under the same pressure drop than that of conventional fin arrangement. This indicates that the heat exchanger of higher efficiency would be designed by the proper combination of fins, of different shapes.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.450-450
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• 2013

플래시 메모리는 소형화가 용이하고, 낮은 구동 전압과 빠른 속도의 소자 장점을 가지기 때문에 휴대용 전자기기에 많이 사용되고 있다. 현재 사용되고 있는 플로팅 게이트를 이용한 플래시 메모리 소자는 비례축소에 의해 발생하는 단 채널 효과, 펀치스루 효과 및 소자 간 커플링 현상과 같은 문제로 소자의 크기를 줄이는데 한계가 있다. 이 문제를 해결하기 위해 FinFET, nanowire FET, 3차원 수직 구조와 같은 구조를 가진 플래시 메모리에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 비례축소의 용이함과 낮은 누설 전류의 장점을 가진 FinFET 구조를 가진 낸드 플래시 메모리의 전기적 특성에 대해 조사하였다. 메모리의 집적도를 높이기 위하여 비대칭 FinFET 구조를 가진 더블 게이트 낸드 플래시 메모리 소자를 제안하였다. 비대칭 FinFET 구조는 더블 게이트를 가진 낸드 플래시에서 각 게이트 간 간섭을 막기 위해 FinFET 구조의 도핑과 위치가 비대칭으로 구성되어 있다. 3차원 TCAD 시뮬레이션툴인 Sentaurus를 사용하여 이 소자의 동작특성을 시뮬레이션하였다. 낸드 플래시 메모리 소자의 게이트 절연 층으로는 high-k 절연 물질을 사용하였고 터널링 산화층의 두께는 두 게이트의 비대칭 구조를 위해 다르게 하였다. 두 게이트의 비대칭 구조를 위해 각 fin은 다른 농도로 인으로 도핑하였다. 각 게이트에 구동전압을 인가하여 멀티비트 소자를 구현하였고 각 구동마다 전류-전압 특성과 전하밀도, 전자의 이동도와 전기적 포텐셜을 계산하였다. 기존의 같은 게이트 크기를 가진 플로팅 게이트 플래시 메모리 소자에 비해 전류-전압곡선에서 subthreshold swing 값이 현저히 줄어들고 동작 상태 전류의 크기가 늘어나며 채널에서의 전자의 밀도와 이동도가 증가하여 소자의 성능이 향상됨을 확인하였다. 또한 양족 게이트의 구조를 비대칭으로 구성하여 멀티비트를 구현하면서 게이트 간 간섭을 최소화하여 각 구동 동작마다 성능차이가 크지 않음을 확인하였다.

• 한국발생생물학회지:발생과생식
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• 제22권3호
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• pp.275-281
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• 2018

The purpose of this study is to examine fluctuating asymmetry of eye diameter, maxilla length, operculum length, and the number of pectoral fin ray and pelvic fin ray between ploidy and sex in diploid and triploid marine medaka, Oryzias dancena. In all experimental groups, eye diameter and maxilla length showed no significant difference between left side and right side (p>0.05). Results of operculum length in triploid male group and pectoral fin ray's number in diploid male group showed similarity ones with results of operculum length in triploid female group and pectoral fin ray's number in diploid female group (p<0.05). However, the operculum length in diploid male group and pectoral fin ray's number in triploid male group showed consinderable difference with those of operculum length in diploid female group and pectoral fin in triploid female group. Findings of pelvic fin ray's number in all groups were similar to those of pectoral fin ray's number in all groups (p<0.01).

• 수산해양기술연구
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• 제32권1호
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• pp.67-77
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• 1996

The heat transfer performance of R - 11 vapor condensing on integral fin tubes has been studied using fin tubes having the fin density from 748 to 1654 fins per meter. Electric heater supplied heat energy to the boiler to generate R - 11 vapor over the range of 25-60W. Condensation rates of each tubes were tested under the condition of cooling water flow rate from 400l/h to 2500l/h. For the seven fin tubes tested, the best performance has been obtained with a tube having a fin density of 1417fpm and a fin height of 1.3mm. This tube has yielded a maximum value of the heat transfer coefficient of 16500W/$m_2$K, at a vapor to wall temperature difference of 3K. Experimental results of integral fin tubes have been compared with available predictive models such as Beatty - Katz's analysis, Webb's analysis, Sukhatme's analysis and Rudy's empirical relation. The experimental results were shown to be in good agreement with that of the Sukhatme's analysis.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 춘계종합학술대회
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• pp.514-516
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• 2007

본 연구에서는 Sentaurus를 이용하여 FinFET를 구현 하고자 한다. 소자의 성능 향상과 누설 전류의 최소화를 지속하기 위해, 반도체 제조자들은 10nm 이하의 소자에 적용될수 있는 새로운 트랜지스터 구조를 연구 하기 시작했다. 가능성 있는 것 중의 하나인 FinFET가 몇년 전 California-Berkeley 대학에서 발표했는데, 상어 등지느러미 같이 생긴 높고 얇은 채널 모양을 이용하는 소자이다. 이러한 설계에서는 지느러미의 한면에 하나씩 두 개의 게이트가 사용되어 소자의 전환을 쉽게 해준다. FinFET는 이러한 구조 때문에 이중 게이트 MOSFET이 라고 불린다. CMOS소자는 수평 적으로 구성되지만, FinFET는 수직으로 구성되기 때문에 이러한 접근은 혁신적이다. 하지만 다른 이중게이트 구조와 달리, FinFET는 표준 CMOS공정에서 크게 벗어나지 않는다. 본 연구에서는 Sentaurus 시뮬레이션 프로그램을 이용하여 FinFET를 구현하고자 한다.