• Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.257-259
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• 2010

This is the first report of Snyderina yamanokami, from the subfamily Tetraroginae of the family Scorpaenidae, collected in Korea. The specimen (175.3 mm long) was caught in the coastal waters of Jeju Island on a commercial longline hook on 9 September 2009. This species is characterized by the following morphological traits: 9-11 dorsal fin rays, 5-6 anal fin rays, 13-15 pectoral fin rays, 5 ventral fin rays, pectoral fin tip reaching or extending past the origin of the anal fin, palatines toothless, and four dark spots on the middle of the body. We suggest a new Korean name, "Keun-mi-yeok-chi," for S. yamanokami.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.753-763
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• 1989

The transient response of a three-dimensional straight fin of constant cross sectional area and perimeter with unequal top, bottom, left, right and tip surface convection coefficients is analyzed using separation variables and Laplace transforms when the fin base is subjected to a step change in temperature. The three-dimensional effects of fin dimensions and unequal fin surface convection coefficients on the fin performance which is expressed in terms of the heat flowrates through the fin base are investigated, and errors in one-dimensions and unequal fin surface coefficients. Typical results are represented in tabular and graphical forms.

• Journal of Mechanical Science and Technology
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• v.20 no.12
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• pp.2203-2208
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• 2006

Both 1-D and 2-D analytic methods are used for a rectangular fin optimization. Optimum heat loss is taken as 98% of the maximum heat loss. Temperature profile using 2-D analytic method and relative error of temperature along the fin length between 1-D and 2-D analytic methods are presented. Increasing rate of the optimum heat loss with the variation of Biot number and decreasing rate of that with the variation of the fin base length are listed. Optimum fin tip length using 2-D analytic method and relative error of that between 1-D and 2-D analytic methods are presented as a function of Biot numbers ratio.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.10
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• pp.808-815
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• 2002

The nonlinear characteristics for hinge of a deployable missile control fin are investigated experimentally. The nonlinearity is caused by a worn or loose hinge and manufacturing tolerance and cannot be eliminated completely. The structural nonlinearity has an effect on the static and dynamic characteristics of the control fin. Therefore, it is necessary to establish the accurate nonlinear model for the hinge of the control fin. In the present study the existence of nonlinearities in the hinge is confirmed from the frequency response experiments such as tip random excitation and base sine sweep. Using the system identification method. especially, ″Force-state Mapping Technique″, the types of nonlinearities are identified and the nonlinear hinge model of the control fin is established.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.848-854
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• 2002

The nonlinear characteristics for the hinge of a deployable missile control fin are investigated experimentally. The nonlinearity is caused by a worn or loose hinge and manufacturing tolerance and cannot be eliminated completely. The structural nonlinearity has an effect on the static and dynamic characteristics of the control fin. Therefore, it is necessary to establish the accurate nonlinear model for the hinge of the control fin. In the present study the existence of nonlinearities in the hinge is confirmed from the frequency response experiments such as tip random excitation and base sine sweep. Using the system identification method, especially, “Force-State Mapping Technique”, the types of nonlinearities are identified and the nonlinear hinge model of the control fin is established.

• Journal of Industrial Technology
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• v.18
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• pp.195-202
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• 1998

The effect of the number of nodes on the heat loss from a rectangular fin for a finite difference method is studied. There are two ways for selecting nodes for the upper half fin in this finite difference method. In the first place, all the ${\Delta}x$ are the same and all the ${\Delta}y$ are the same for the entire upper half fin. Incremental length of x (i.e. ${\Delta}x$) is divided by two near the fin tip while all the ${\Delta}y$ are the same for another way. The results show that 1) About 30 nodes are enough to obtain the satisfactory exact analysis (relative error < 5%) on the heat loss for a given range of Biot number in case of short fin (i.e. $L{\leq}2$). 2) Under usual circumstances (Bi<0.1), the relative error of heat loss between using 30 nodes and 90 nodes is within 4% for given range of non-dimensional fin length. 3) The relative error of the calculated heat loss (the number of node=90) as compared to the expected exact heat loss is less then 1.5% for Bi=0.1 and L=10 while that is over 13% for Bi=1.0 and L=10.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.453-462
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• 1990

The interaction of forced convection-conduction with thermal radiation in laminar boundary layer over a plate fin is studied numerically. The analysis is based on complete solution whereby the heat conduction equation for the fin is solved simultaneously with the conservation equations for mass, momentum and energy in the fluid boundary layer adjacent to the fin. The fluid is a gray medium and diffusion(Rosseland) approximation is used to describe the radiative heat flux in the energy equation. The resulting boundary value problem are convection-conduction parameter N$_{c}$ and radiation-conduction parameter m, Prandtl number Pr. Numerical results are presented for gases with the Prandtl numbers of 0.7 & 5 with values of N$_{c}$ and M ranging from 0 to 10 respectively. The object of this study is to provide the first results on forced convection-radiation interaction in boundary layer flow over a semi-infinite flay plate which can be used for comparisons with future studies that will consider a more accurate expression for the radiative heat flux. The agreement of the results from the complete solution presented by E. M. Sparrow and those from this paper for the special case of M=0 is good. The overall rate of heat transfer from the fin considering radiative effect is higher than that from the fin neglecting radiative effect. The local heat transfer coefficient with radiative effect is higher than that without radiative effect. In the direction from tip to base, those coefficients decrease at first, attain minimum, and then increase. The larger values of N$_{c}$ M, Pr give rise to larger fin temperature variations and the fin temperature without radiative effect is always higher than that with radiative effect.

• Korean Journal of Ichthyology
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• v.28 no.2
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• pp.116-120
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• 2016

A specimen of Cocotropus masudai (41.2 mm in standard length), belonging to the family Aploactinidae, was firstly collected from the eastern coastal waters of Jejudo Island, Korea by using a fish trap in July 2011. This species is characterized by having the following morphological traits: XII, 9 dorsal fin rays; I, 8 anal fin rays; 12 pectoral fin rays; I, 3 pelvic fin rays; five preopecular spines; five sensory pores present on lower jaw and isthmus tip beyond fifth sensory pore. This species is similar to C. izuensis except for the number of preopercular spines (five in C. izuensis vs. four in C. masudai) and the anterior position of the isthmus (well beyond the fifth lower jaw sensory pore vs. the tip mostly reaching to the pore). In Korea, C. masudai can be easily distinguished from the Erisphex pottii in having the dorsal fin with nine soft rays (vs. 10~14 for Erisphex pottii), anal fin with seven soft rays (vs. 10~13) and pelvic fin with three soft rays (vs. two). We propose new Korean names, "Dot-chi-sok" and "Dot-chi" for the genus and species, respectively.

• Animal cells and systems
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• v.11 no.2
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• pp.135-139
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• 2007

One specimen of the percophid fish, Pteropsaron evolans Jordan and Snyder and two specimens of the labrid fish, Xyrichtys verrens (Jordan and Evermann) were newly collected from Jeju Island of Korea. P. evolans is characterized by having one pair of spines at snout, cheek without scales, and elongated first dorsal fin in male. X. verrens is easily distinguished by having tip of pectoral fin black, many rows of scales on cheek, and an elongated pelvic fin. We describe as new to Korean fish fauna and propose new Korean names, "Sil-nun-tung-i" for the former and "Jang-mi-ok-du-nol-rae-gi" for the latter.

• Korean Journal of Ichthyology
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• v.12 no.3
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• pp.203-207
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• 2000

The synaphobranchid eel, Dysomma anguillare was redescribed on the basis of a specimen collected from the Yellow Sea, Chollabuk-do, Korea. The D. anguillare was characterized by many fleshy plicae at the front of upper and lower jaws, dorsal fin originated in slight advance than pectoral fin base, degenerated eyes, very short trunk and long tail, anus located below near tip of pectoral fin and no scales.