• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.11 no.3
• /
• pp.52-57
• /
• 1982

One-dimensional approximation for fin problems is widely used in current texts and industrial practice. The errors caused by this approximation is analysed for a longitudinal triangular fin by the numerical solution of two-dimensional fin equation. Two-dimensional solution is obtained by the finite element method and com pared with the one-dimensional esact solution. The results show that total heat transfer and fin efficiency are overestimated by the one-dimensional approximation. The factors which cause these errors are the Biot number (Bi) and the ratio of fin length to half the thickness (L/a). When Bi is smaller than 1.0 these errors are smaller than $10\%$, but when Bi is larger than 5.0 they are a few ten percents. Fin efficiency obtaned by one-dimensional and long fin assumption is valid only then Bi is small and L/a is large.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.14 no.5
• /
• pp.508-517
• /
• 2014

We design and analyze the n-channel junctionless fin-shaped field-effect transistor (JL FinFET) with 10-nm gate length and compare its performances with those of the conventional bulk-type fin-shaped FET (conventional bulk FinFET). A three-dimensional (3-D) device simulations were performed to optimize the device design parameters including the width ($W_{fin}$) and height ($H_{fin}$) of the fin as well as the channel doping concentration ($N_{ch}$). Based on the design optimization, the two devices were compared in terms of direct-current (DC) and radio-frequency (RF) characteristics. The results reveal that the JL FinFET has better subthreshold swing, and more effectively suppresses short-channel effects (SCEs) than the conventional bulk FinFET.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.11
• /
• pp.2373-2377
• /
• 2009

In this paper, the threshold voltage characteristics have been analyzed using three dimensional Poisson's equation for FinFET. The FinFET is extensively been studing since it can reduce the short channel effects as the nano device. We have presented the short channel effects such as subthreshold swing and threshold voltage for PinFET, using the analytical three dimensional Poisson's equation. We have analyzed for channel length, thickness and width to consider the structural characteristics for FinFET. Using this model, the subthreshold swing and threshold voltage have been analyzed for FinFET since the potential and transport model of this analytical three dimensional Poisson's equation is verified as comparing with those of the numerical three dimensional Poisson's equation.

• Journal of Advanced Marine Engineering and Technology
• /
• v.34 no.6
• /
• pp.798-805
• /
• 2010

There are no domestic researches of plate fin heat exchanger in the field of cryogenic such as LNG FPSO liquefaction plant. In this study, condensing heat transfer characteristics of nitrogen according to three kinds of fin type in the plate fin heat exchanger were analyzed through simulation and experiment to secure independent technologies. In the simulation, nitrogen was condensed at 69bar and $-140^{\circ}C$ in serrated and wavy fin of plate-fin heat exchanger. The serrated fin shows the highest value of local heat transfer coefficient, followed by wavy and plain fin. The experimental results were shown errors less than 12% comparing with the simulation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.10a
• /
• pp.928-930
• /
• 2009

In this paper, the threshold voltage characteristics have been alanyzed using three dimensional Poisson's equation for FinFET. The FinFET is extensively been studing since it can reduce the short channel effects as the nano device. We have presented the short channel effects such as subthreshold swing and threshold voltage for FinFET, using the analytical three dimensional Poisson's equation. We have analyzed for channel length, thickness and width to consider the structural characteristics for FinFET. Using this model, the subthreshold swing and threshold voltage have been analyzed for FinFET since the potential and transport model of this analytical three dimensional Poisson's equation is verified as comparing with those of the numerical three dimensional Poisson's equation.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.14 no.5
• /
• pp.525-536
• /
• 2014

Recently, the first generation of mass production of FinFET-based microprocessors has begun, and scaling of FinFET transistors is ongoing. Traditional capacitance and resistance models cannot be applied to nonplanar-gate transistors like FinFETs. Although scaling of nanoscale FinFETs may alleviate electrostatic limitations, parasitic capacitances and resistances increase owing to the increasing proximity of the source/drain (S/D) region and metal contact. In this paper, we develop analytical models of parasitic components of FinFETs that employ the raised source/drain structure and metal contact. The accuracy of the proposed model is verified with the results of a 3-D field solver, Raphael. We also investigate the effects of layout changes on the parasitic components and the current-gain cutoff frequency ($f_T$). The optimal FinFET layout design for RF performance is predicted using the proposed analytical models. The proposed analytical model can be implemented as a compact model for accurate circuit simulations.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.2
• /
• pp.338-348
• /
• 1988

This study presents an analysis of periodic heat diffusion in an annular fin with uniform thickness. When the temperature of the fin base is changed in the form of a sinusoidal function, the exact temperature solution can be obtained by Laplace transformation in terms of the dimensionless parameters in the infinite series. Local heat flux and average heat flux, local fin efficiency and average fin efficiency were obtained. Particularly, the table of eigenvalues that are the indispensable condition in solving the heat transfer problem of annular fin in a transient state with convection phenomena at the fin edge is provided. The tables of heat fluxes and average heat fluxes, fin efficiencies and average fin efficiencies are also provided from the computed results. Also, substituting the variations of dimensionless parameters into the these exact solutions, the characteristics of these response are investigated.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.9
• /
• pp.2316-2327
• /
• 1995

Experimental results from nucleate pool boiling heat transfer with various finned tubes in CFC11, HCF123 and HCFC141b are reported. One plain tube and four low fin tubes of various fin densities were tested in an attempt to find out the optimum fin density in the heat flux range of 10-60 kW/m$^{[-992]}$ at near atmospheric pressure. The results indicated that CFC11 showed the highest heat transfer coefficients. Its alternatives, HCFC123 and HCFC141b, showed 3-5% lower heat transfer coefficients than those of CFC11 at the same heat flux. As the fin density increases, so does the heat transfer surface area. Measured heat transfer coefficients, however, do not necessarily always increase as the fin density increases. This unique phenomenon seems to be caused by the coalescence of the bubblers that prevent the cool liquid from entering into the fin valleys. For all the refrigerants tested, the optimum fin density yielding the highest performance was 28 fins per inch confirming the previous results by other researchers.

• Ocean and Polar Research
• /
• v.26 no.4
• /
• pp.685-688
• /
• 2004

The morphology of the post-larva of Liopropoma japonicum of the family serranidae is described from one specimen collected off Jeju Island ($32^{\circ}42'N,\;127^{\circ}45'E$) on May 3, 2001. The body is laterally compressed and caudal peduncle deep at 19.4 mm BL. Anus locates at a vertical through posteriormost(8th) dorsal-fin spine. Dorsal fin rays were VIII, 14; anal fin rays III, 10; pectroal fin rays 16; pelvic fin rays I, 5. A caudal fin is rounded. Length of elongate second and third dorsal-fin spines are 499% and 423% of the body length, respectively. A series of 50 sensory pores on body is elongated to caudal fin. Head spination is well developed. Melanophores are moderately large and dense in the head, and are small and rare in teh neck. Being freshly collected, the body color is yellowish-red and tail is semitransparent. The head is yellowish-red and the brain is dark-red.

• Solar Energy
• /
• v.10 no.1
• /
• pp.14-21
• /
• 1990

The entropy generation rate in a fin-tube heat exchanger is investigated as a basis for thermodynamic optimization associated with single fin-tube heat exchanger. The entropy generation (irreversibility)analysis is used to find the optimum design factor and investigate total entropy generation, optimum dimensions of fin length, tube inner and outer diameters, and fin spacing on the variation of design factors. The results of this study are as follows: As the outer diameter increases, optimum !in spacing and fin length increase but the entropy generation and optimum inner diameter decrease; As fin thickness increases, the entropy generation of system and optimum fin spacing increase; As fin length increases, entropy generation and optimum outer diameter increase.