• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.4
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• pp.24-31
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• 2011

Performance of the asymmetric trapezoidal fin with various upper lateral surface slopes is investigated by using the two-dimensional analytic method. For a fin base boundary condition, convection from the inner fluid to the inner wall, conduction from the inner wall to the fin base and conduction through the fin base are considered. Heat loss and fin efficiency are represented as a function of the fin base thickness, base height, inner fluid convection characteristic number, fin tip length and fin shape factor. One of the results shows that heat loss increases while fin efficiency decreases as the fin shape factor increases.

• International Journal of Air-Conditioning and Refrigeration
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• v.16 no.3
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• pp.83-88
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• 2008

A geometrically asymmetric trapezoidal fin is analyzed using the one-dimensional analytic method. Heat loss and thermal resistance are represented as a function of the fin base thickness, base height, fm shape factor, inside fluid convection characteristic number, convection characteristic numbers ratio, fm length and ambient convection characteristic number. The relationship between the fin base height and the shape factor for equal amounts of heat loss is presented. One of the results shows that the variations of the fm base thickness and the inside fluid convection characteristic number give no effect on the thermal resistance.

• Journal of Applied Reliability
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• v.10 no.1
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• pp.65-71
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• 2010

NAND-type SONOS with a separated double-gate FinFET structure (SDF-Fin SONOS) flash memory devices are proposed to reduce the unit cell size of the memory device and increase the memory density in comparison with conventional non volatile memory devices. The proposed memory device consists of a pair of control gates separated along the direction of the Fin width. There are two unique alternative technologies in this study. One is a channel doping method and the other is an oxide thickness variation method, which are used to operate the SDF-Fin SONOS memory device as two-bit. The fabrication processes and the device characteristics are simulated by using technology comuter-adided(TCAD). The simulation results indicate that the charge trap probability depends on the different channel doping concentration and the tunneling oxide thickness. The proposed SDG-Fin SONOS memory devices hold promise for potential application.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.6
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• pp.440-447
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• 2001

This study investigate experimentally the effect of in height, thickness, and clearance on the boiling heat transfer. The heat surfaces having copper fin array is tested for pool boiling. The gas-liquid exchange interference is investigated based on fin array clearance. These test results can be applied to the design of tube bundle system. The fin height of 2 mm is found to be effective. Effects of heat transfer promotion reaches the highest level when the fin clearance is 0.5mm. Also, heat flux is increased when the fin thickness is smaller. But0.2 mm fin thickness is highly recommended.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.6
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• pp.81-87
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• 2008

A geometrically asymmetric trapezoidal fin with variable fin base thickness and height is optimized based on the fixed fin base height using a one-dimensional analytic method. The temperature profile along the normalized X position in the fin is presented. For the fixed fin base height, the optimum heat loss, fin length and efficiency as a function of inside fluid convection characteristic number, fin base thickness and height, fin shape factor, convection characteristic numbers ratio and ambient convection characteristic number are represented. One of the results shows that the effect of fin base height and ambient convection characteristic number on the optimum values is remarkable.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2091-2096
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• 2007

This paper presents a mathematical model for predicting the frost behavior formed on heat exchanger fins, considering fin heat conduction under frosting condition. The model is composed of air-side, the frost layer, and fin region, and they are coupled to the frost layer. The frost behavior is more accurately predicted with fin heat conduction considered (Case A) than with a constant fin surface temperature assumed (Case B). The results indicate that the frost thickness and heat transfer rate for Case B are over-predicted in most regions of the fin, as compared to those for Case A. Also, for Case A, the maximum frost thickness varies little with the fin length variations, and the extension of the fin length over 30 mm contributes insignificantly to heat transfer.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.11
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• pp.817-823
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• 2008

A pin fin with variable fin base thickness is optimized based on the ratio of heat loss to the maximum heat loss using a two-dimensional analytic method. The temperature profile along the normalized radius position in the fin is presented. For fixed fin outer radius, the optimum heat loss, fin length and efficiency as a function of fin base thickness, outer radius, convection characteristic numbers ratio and ambient convection characteristic number are presented. One of the results shows that the effect of fin outer radius and ambient convection characteristic number on the optimum fin length is remarkable.

• Journal of computational fluids engineering
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• v.22 no.1
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• pp.67-80
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• 2017

The high-speed bypass effect on the heat exchanger performance has been investigated numerically. The plate-fin type heat exchanger was modeled using two-dimensional porous approximation for the fin region. Governing equations of mass, momentum, and energy equations for compressible turbulent flow were solved using ideal-gas assumption for the air flow. Various bypass-channel height were considered for Mach numbers ranging 0.25-0.65. Due to the existence of the fin in the bypass channel, the main flow tends to turn into the core region of the channel, which results in the distorted velocity profile downstream of the fin region. The boundary layer thickness, displacement thickness, and the momentum thickness showed the variation of mass flow through the fin region. The mass flow variation along the fin region was also shown for various bypass heights and Mach numbers. The volumetric entropy generation was used to assess the loss mechanism inside the bypass duct and the fin region. Finally, the correlations of the friction factor and the Colburn j-factor are summarized.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.907-909
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• 2009

In this paper, the dependence of threshold voltage on the gate oxide thickness, which it mostly influenced on short channel effects in fabrication of FinFET, has been investigated. The transport model based on three dimensional Possion's equation has been used to analyze influence on gate oxide thickness. The gate oxide thickness is the most important factor to influence on the threshold voltage in nano structure FinFET. The potential distributions of this model are compared with those of three dimensional numerical simulation to verify this model. As a result, since potential model presented in this paper is good agreement with hree dimensional numerical model, the threshold voltage characteristics have been considered according to the gate oxide thickness of FinFET.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.798-803
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• 2009

In this study, dimensionless correlations of frost properties (i.e. the thickness and surface temperature of frost) on heat exchanger fin with nonuniform temperature distribution are proposed from frosting experiments. We analyzed the local fin temperature distribution, frost thickness and frost surface temperature on a 2D fin; in the airflow direction and the direction perpendicular to airflow. As a result, the frost growth on the fin had a close relation with fin heat conduction. The dimensionless correlations for the average frost properties were expressed as a function of dimensionless temperature, humidity ratio, Reynolds number, and Fourier number. These correlations agreed well with experimental data with the error less than 14%.