• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.179-184
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• 2010

This experimental study investigated the effect of tip clearance and bypass flow on the cooling performance of a straight fin heat sink. Both the horizontal and vertical directions of the bypass flow were studied by using a mass flow controller and test sections. The thermal resistance of a heat sink was obtained to elucidate the response of the cooling performance to tip clearance and bypass flow. The thermal resistance of a straight fin heat sink gradually increases with increasing tip clearance. A flow guide unit was employed to reduce the bypass flow. An optimal distance from the leading edge of the heat sink to the flow guide unit was found for the fixed volume flow rate. The contribution of the flow guide unit to the thermal performance of a heat sink increases with increasing volume flow rate.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.5
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• pp.389-395
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• 2017

This paper showed the difference in the optimum conditions by using the ANSYS CFX simulation program with the changes of the main-blade angle and sub-blade angle. Main-blade Shape 4,which had angle $45^{\circ}$ while other Shapes with angle $0^{\circ}$, was increased to 157.2[%] to 263.2[%] in the power and was increased to 110[%] to 250[%] in the power coefficient. Moreover, when the Shape 5 Fin length of main-blade doubled, the power was 70.8[%] when compared with Shape 1 and 27.5[%] with shape 4.If the main-blade geometry equals shape 1 in the case structure, The power of Case1 was increased to 13.3[%] when compared with Case2. Also, the power coefficient was increased to 15.4[%]. When sub-blade angle was $45^{\circ}$, main-blade was better than the Fin type than the Bended type. The power of Case4 was increased to 47[%] when compared with Csae1 and increased to 13.6[%] with Case 3. Also, the power coefficient was 46.7[%] when compared with Case 1 and 15.8[%] with Case 3.

• Journal of the Korean Society of Costume
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• v.50
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• pp.161-182
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• 2000

The results of this study were as follows: The quit has been used for warmth supporting materials protection religious uses decoration and giving stability of shapes. Quilt is developed from monk's robe of lags and the word 'nubi' is originated form 'nabeui' in both Korean and Japan. Korean quilt was used mainly for warmth: Japanese one was used for warmth and supporting materials. The techniques used for traditional Korean quit were parallel vertical hand stitches. On the other hand Japanese traditional quilt uses various motifs of sashiko which is similar to embroidery and named by region. Korean quilt can be divided into three types by the stitch intervals: Fin quit(Jan unbi) Medium quilt(Jung nubi) and Wide quilt(Demun nubi). Japanese quilt has been developed in east-north region and can be grouped into sashiko kogin and hishizashi by motifs of quit. Korean quilt costumes are stuffed with cotton between the outer fabrics and linings and stitched vertically on the fabrics Main fabrics used were silk and cotton. Japanese quilt costume uses cotton yarns for stitching on flax or cotton fabrics used were silk and cotton. fabrics and main uses of the quilot costumes were sorking clothes of working classes. Both Korean and Japanese quilt costumes contain of family's health happiness and longevity. In summary Korean quilts use two layers of fabrics and stuff them with cotton and stitch parallel vertical i\lines to provide warmth Japanese quilt are sashiko which is stitches of strand in various shapes using cotton yarns. differ by region and are made for warmth and supporting materials.

• Journal of computational fluids engineering
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• v.7 no.3
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• pp.53-59
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• 2002

A two-dimensional laminar flow through a channel with a pair of symmetric vertical fins is investigated. At far up- and down-stream from the fins, the plane Poiseuille flow exists in the channel. The Stokes flow for this channel is first investigated analytically and then the other laminar flows by numerical method. For analytic method, the method of eigen function expansion and collocation method are employed. In numerical solution for laminar flows, finite difference method(FDM) is used to obtain vorticity and stream function. From the results, the streamline patterns are shown and the additional pressure drop due to the attached fins and the force exerted on the fin are calculated. It is clear that the force depends on the length of fins and Reynolds number. When the Reynolds number exceeds a critical value, the flow becomes asymmetric. This critical Reynolds number Re/sub c/ depends on the length of the fins.

• Ocean and Polar Research
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• v.30 no.3
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• pp.347-349
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• 2008

A single juvenile of the jawfish Stalix toyoshio (24.0 mm standard length) was collected from the South Sea of Korea at a depth of 135 m during box-corer sampling. The specimen was characterized by the absence of stripes on both the body and vertical fins, well-developed cephalic pore systems, yellowish body and fins, six transversely-forked dorsal fin spines, and five mandibular pores. Here, we describe the specimen, which represents the first record of S. toyoshio from Korea and the second record from the northwestern Pacific.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.545-550
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• 2001

A two-dimensional laminar flow through a channel, on which a couple of symmetric vertical fins are attached, is investigated. The stokes flow for this channel flow is investigated analytically and laminar flow numerically. For analytic solution, the method of eigen function expansion and collocation method are employed. For numerical solution, finite difference method(FDM) is used to obtain vorticity and stream function. From the results, streamline patterns are shown and the pressure drop due to the attached fins is calculated, which depends on the length of fins and Reynolds number. While $Re, streamline pattern is symmetric, a pair of additional asymmetric solutions appear for $Re>Re_c$, where the critical Reynolds number $Re_c$ depends on the length of the fin.

• Journal of the Korean Society of Visualization
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• v.5 no.2
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• pp.20-25
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• 2007

The geometry of a commercial passenger airplane is realized based on a Boeing 747-400 model through the photographic scanning and reverse engineering. The each element consisting of the plane such as fuselage, wing, vertical fin, stabilizer and engines, is individually generated and then the whole body is assembled by the photomodeler. The maximum error in the realized airplane is about 1.4% comparing with the real one. The three-dimensional inviscid steady compressible governing equations are solved in the unstructured tetrahedron grid system, and in a finite volume method using STAR-CD when the airplane flies at the cruise condition. The pressure distribution on the surface and the wing-tip vortices are visualized, and in addition to the aerodynamics coefficients, lift and drag are estimated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.274-279
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• 2010

The present work is to analyze the longitudinal static stability and the drop trajectory of fighter aircraft's external fuel tank, of which horizontal fin is modified as the 20% scale down size compared with the original one. The analytical results to the pitching stability of external fuel tank using a thin airfoil's aerodynamic force data show the corresponding tendency to results of wind tunnel experiment. Results of trajectory simulation by the 6 degree of freedom equations of motion, comparing with drop trajectories of wind tunnel experiment, are shown that aircraft's attitude affects strongly on horizontal movement but not on the vertical movement. Those results give the reliability to aircraft safety when the external fuel tank with the 20% reduced horizontal fins is released from aircraft based on the flight manual.

• Korean Journal of Ichthyology
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• v.13 no.4
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• pp.274-278
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• 2001

The morphology is described of a post larva of Pomacanthus xanthometopon of the family Pomacanthidae collected in the West Pacific ($26^{\circ}9'N$, $125^{\circ}0'W$) on May 5, 2001. The specimen is moderate to deep bodied and laterally compressed. Body depth is 66.3% of body length at 8.0 mm BL. The body is covered with small spine groups, each composed of two to four spines. The anus located at a vertical through the 8th or 9th dorsal fin spine. There is no strong spine at the angle of the preopercle that appears in the adult stage. Small pigments are spread dorsally on the head, upper trunk and over the membrane of dorsal fin, from the 1st to 11th ray.

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.366-371
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• 2023

A shrimp goby, Amblyeleotris japonica is reported firstly from Korea, based on a single specimen (70.3 mm in SL) collected at a depth of 14 m in the southern Jejudo Island. The species is characterized by having a lower number of scales in longitudinal series, a rather compressed body, anterior limit of opercular opening located below between posterior margin of eye and preopercle, second dorsal fin with a single spine and 13 soft rays, anal fin with a single spine and 14 soft rays, and five brownish vertical bands on lateral body between head and caudal peduncle when fresh. New Korean names, "Se-u-but-i-mang-dug-sog" and "Bulg-eun-dong-gal-se-u-but-i-mang-dug", are proposed for the genus and the species, respectively.