• 설비공학논문집
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• 제20권7호
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• pp.455-461
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• 2008

A reversed trapezoidal fin with variable fin base thickness is optimized using a two-dimensional analytical method. For the fin base boundary condition, instead of a constant temperature, heat transfer from the inside fluid to the fin base is considered. Heat loss from the fin tip is not ignored. The maximum heat loss, corresponding optimum fin effectiveness, fin length and base height are presented as a function of the fin base thickness, shape factor and volume.

• International Journal of Air-Conditioning and Refrigeration
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• 제13권3호
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• pp.145-151
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• 2005

A thermally asymmetric straight rectangular fin is analysed and optimized using the two-dimensional separation of variables method. The optimum heat loss is presented as a function of bottom to top Biot number ratio, fin base length and top Biot number. Decreasing rate of the optimum fin length with the increase of the fin base length is listed. The optimum fin tip length is shown as a function of bottom to top Biot number ratio, fin base length and tip to top Biot number ratio. One of the results shows that the optimum heat loss and the actual optimum fin length decrease while the optimum fin tip length increases as the fin base length increases.

• 진공이야기
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• 제3권1호
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• pp.16-21
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• 2016

FinFETs are able to be scaled down to 22 nm and beyond while suppressing effectively short channel effect, and have superior performance compared to 2-dimensional (2-D) MOSFETs. Bulk FinFETs are built on bulk Si wafers which have less defect density and lower cost than SOI(Silicon-On-Insulator) wafers. In contrast to SOI FinFETs, bulk FinFETs have no floating body effect and better heat transfer rate to the substrate while keeping nearly the same scalability. The bulk FinFET has been developed at 14 nm technology node, and applied in mass production of AP and CPU since 2015. In the development of the bulk FinFETs at 10 nm and beyond, self-heating effects (SHE) is becoming important. Accurate control of device geometry and threshold voltage between devices is also important. The random telegraph noise (RTN) would be problematic in scaled FinFET which has narrow fin width and small fin height.

• 대한기계학회논문집B
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• 제26권8호
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• pp.1191-1200
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• 2002

The measurements of velocity vectors are made in the near wake(X/d=5.0) of a circular cylinder with serrated fins. Velocity of fluid which flow through fins decreases as increasing fin height and freestream velocity and decreasing fin pitch. Therefore the velocity distribution at X/d=0.0 has lower gradient with increasing freestream velocity and fin height and decreasing fin pitch. The discontinuity of the streamwise velocity gradient is observed near the fin edge and causes significant changes in V-component velocity distribution in the near wake. This change attributes to the differences in Strouhal number and entraintment flow behavior. Increased turbulent intensity around a circular cylinder due to the serrated fins and entrainment flow are important factors for the recovery of velocity defect. The widths of velocity and turbulent intensity distribution of fin tubes are wider than those of a circular cylinder. The normalized velocity and turbulent intensity distributions with a hydraulic diameter which is proposed in this paper are in closer agreement with those of a circular cylinder.

• 설비공학논문집
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• 제12권4호
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• pp.388-397
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• 2000

Comparison of the heat conduction into a trapezoidal fin and the heat loss from the fin by convection is made in this study Also, the ratio of heat loss from each surface to the total heat loss and the temperature distribution are analyzed using a 3-D analytical method. A trapezoidal fin whose tip height is half the root height is chosen as the model. The results show that the heat transfer rates from the tip and from both sides are comparable with each other as the non-dimensional width and length vary while the heat transfer rate from the bottom and top is dominant.

• International Journal of Air-Conditioning and Refrigeration
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• 제10권4호
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• pp.192-200
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• 2002

A modified asymmetric rectangular fin is analysed using the two-dimensional separation of variables method. This modified rectangular fin is made by attaching the wing on the top side of a rectangular fin. Heat loss from each side of this modified rectangular fin is calculated. The relative increasing ratio of heat loss between a modified rectangular fin and a rectangular fin is presented as a function of dimensionless fin volume, wing height and the location of the wing. Especially, to show the remarkable effect of the wing on the heat loss, the relative increasing ratios of heat loss between two different volume increasing methods are listed.

• 신재생에너지
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• 제2권1호
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• pp.46-55
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• 2006

The performance enhancement of heat exchanger in the drying system using solar collector with evacuated tubes is analyzed. First, for this analysis, the heat loss from a reversed trapezoidal fin attached at the pipe is calculated as a function of convection characteristic number ratio, fin base length and fin tip length. Also, the optimum heat loss and fin tip length of the fin under certain conditions are presented. The overall surface effectiveness of the cylinder with reversed trapezoidal fins in the heat exchanger are shown as a function of half fin base height, fin lateral slope and fin tip length.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.118-124
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• 2003

응축기, 증발기, 전열관에 사용되는 Fin Tube는 열전달효율 향상을 위하여 Fin의 높이 를 증가시키고, Tube의 최소두께를 얇게 가공하는 경향으로 발전하고 있다. 따라서, Fin Tube의 와전류탐상(ECT; Eddy Current Testing)에 의한 결함검출에 더욱 어려움이 예상된다. 본 연구에서는 Fin Tube의 Fin 높이를 3단계로 변화시켜 Tube를 제작하고, Tube에 축 방향결함, 원주방향결함, 원형결함을 각각 Fin Tube의 안쪽에 최소두께의 20%, 40%, 60% 의 동일결함율을 갖는 인공결함 시험편을 제작하였다. 제작한 원형결함시험편에 와전류탐상을 수행하여 Fin 높이에 따른 최적주파수의 변화를 연구하였다. Fin높이가 다른 원형결함 시험편에 1~20KHz 주파수를 적용한 결과 최적주파수는 12KHz로 Fin높이에 크게 영향을 받지 않음을 밝혔다 또한 Fin높이에 따른 최적주파수변화는 크지 않으나 Fin 높이가 높을수록 100%관통결함의 위상각(40')에 근접하여 나타났다. 축방향결함, 원주방향결함, 원형결함을 갖는 시험편에 와전류탐상을 수행한 결과 원형결함을 갖는 시험편의 신호 감도가 축방향결함, 원주방향결함보다 좋게 나타났다.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1497-1502
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• 2013

Recently, the junctionless (JL) transistors realized by a single-type doping process have attracted attention instead of the conventional metal-oxide-semiconductor field-effect transistors (MOSFET). The JL transistor can overcome MOSFET's problems such as the thermal budget and short-channel effect. Thus, the JL transistor is considered as great alternative device for a next generation low standby power silicon system. In this paper, the JL FinFET was simulated with a three dimensional (3D) technology computer-aided design (TCAD) simulator and optimized for DC characteristics according to device dimension and doping concentration. The design variables were the fin width ($W_{fin}$), fin height ($H_{fin}$), and doping concentration ($D_{ch}$). After the optimization of DC characteristics, RF characteristics of JL FinFET were also extracted.

• 대한기계학회논문집B
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• 제34권3호
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• pp.229-235
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• 2010

원관 내부반경이 변하는 사각형상 환형 훤의 최적 값들이 변수 분리법에 의하여 제시된다. 최적의 열손실이 존재할 수 있는 주위 대류특성계수의 범위가 나열된다. 최적 열손실, 그와 관련된 최적의 훤 유용성, 훤 길이 그리고 훤 높이가 원관 내부반경, 내부유체 대류특성계수, 훤 체적, 그리고 주위 대류특성계수의 함수로 표현된다. 결과 중 하나는 훤 체적과 훤 바닥반경이 고정되었을 때 최적 열손실, 유용성 그리고 훤 길이는 원관 내부반경의 증가에 따라 선형적으로 증가함을 보여준다.