• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.252-261
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• 2021

The egg development and early life history of short barbel gudgeon Squalidus japonicus coreanus were investigated. For the experiments, the mature adults were collected at the stream Jicheon in Korea. The eggs from the females were obtain by injecting 10 IU/g of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were 1.12±0.03 mm (1.10~1.16 mm, n=30) in diameter. The embryo began to hatch about 49 hrs after fertilization under water temperature of 23±1℃. The newly-hatched larvae (Yolksac larva) were 3.7±0.1 mm (3.4~3.8 mm, n=16) in total length, and they haven't Melanophore. 5 days after hatching, the Preflexion larva were 5.3±0.2 mm (5.0~5.5 mm, n=16) in total length, and they began to eat a Rotifer. 19 days after hathing, the Flexion larva were 6.0±0.3 mm (5.4~6.5 mm, n=16) in total length, and they began to eat a Brine shrimp. 29 days after hatching, the Postflexion larva were 9.6±0.5 mm (8.3~10.5 mm, n=16) in total length, and dorsal fin rays are were formed. 44 days after hatching, the juvenile were 15.5±1.0 mm (13.5~17.0 mm, n=16) in total length, and all their fin-rays were formed.

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.222-231
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• 2020

The egg development and early life history of Sharpbelly Hemiculter leucisculus were investigated. For the experiments, the mature adults were collected at the Lake Yedang in Korea. The eggs from the females were obtained by injecting 10 IU/g of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were 0.97±0.02 mm (0.9~1.0 mm n=30) in diameter. The embryo began to hatch about 32 hrs after fertilization under water temperature of 22±1℃. The newly-hatched larvae were 3.0±0.2 mm (2.6~3.4 mm, n=15) in total length, and they haven't Melanophore. Six days after hatching, the Preflexion larva were 5.7±0.1 mm (5.4~5.8 mm, n=15) in total length, and they began to eat a Rotifer. 17 days after hatching, the Flexion larva were 6.8±0.2 mm (6.5~7.0 mm, n=15) in total length, and a gas bladder develop above the intestine. 30 days after hatching, the Postflexion larva were 8.8±0.7 mm (7.9~10.3 mm, n=15) in total length, three dorsal fin rays began to develop in the membrane fins. 50 days after hatching, the Juvenile were 20.8±0.8 mm (18.8~24.6 mm, n=15) in total length, and all their fin-rays were formed.

• 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.

• Korean Journal of Ichthyology
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• v.24 no.4
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• pp.302-305
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• 2012

Two specimens (332.0~377.6 mm in standard length) of Benthodesmus tenuis (G$\ddot{u}$nther), belonging to the family Trichiuridae, firstly collected in off Heuksan-do and Yeosu, Jeollanam-do by the bottom trawl. This species was characterized by the following morphological traits: 125~126 dorsal fin rays (vs. 144~155 for B. pacificus), I, 73 anal fin rays (vs. 91~101), interorbital region flat (vs. interorbital region with prominent crest for A. anzac), opercular black and caudal fin forked. We propose a new Korean name, "Se-jang-gal-chi-sok" and "Se-jang-gal-chi" for the genus and species, respectively.

• Korean Journal of Ichthyology
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• v.7 no.2
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• pp.101-108
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• 1995

Four specimens of Megalaspis cordyla(Linnaeus) belonging to the family Carangidae and three specimens of Champsodon snyderi Franz belonging to the family Champsodontidae were collected for the first time from Nam-hae and Pusan, Korea. Megalaspis cordyla is similar to other genera, but differs in some morphological charac-ters : the presence of finlets, the beginning portion and shape of scutes, and the length of pec-toral fin. A new Korean name "Ko-d$\breve{u}$ng-ka-ra-ji" is proposed for the M. cordyla. Champsodon snyderi is differs from C. capensis in the number of pectoral fins and the pres-ence of scale on cheek ; from C. longipinnis in having a pale spinous dorsal fin ; from C. guen-theri and C. machaeratus in having 11 lower gill rakers, 19 soft dorsal fin rays. A new Korean name "Ak-$\hat{o}$-chi" is proposed for the C. snyderi.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.2 no.1
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• pp.1-7
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• 2006

This paper was studied for optimum design of the used vaporizer at a satellite station. Generally, the cold air is created by temperature drop on the vaporizer surface. In addition, the frost creates ice deposit layer, therefore, heat transfer on vaporizer decreases into the adiabatic condition. By this reason, recent vaporizer system is installed as parallel type, and it takes three times of vaporizer capacity. But this vaporizer system requires much installation costs and restricted by some space. It is very important to solve this problem. This study paper is regarding $LN_2$ vaporizer where the utilization increases recently. There are three variable conditions which are used in this study research. First, fin lengths of 4000mm, 6000mm, 8000mm and 0, 4, 8 fin types were applied rut each vaporizer. Second, we applied four season condition which consist of humidity, temperature and air velocity to the experimental environment. Finally, pressure was applied to get flow rate during experiment. This paper objective is to propose vaporizer type and length data for best performance of vaporizer through experiment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.1
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• pp.14-25
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• 2003

The purpose of this study was to analyze the stress pattern in different bone densities surrounding fin-type implant fixtures under the vertical and inclined loads ($30^{\circ}) of 200N. Von-Mises stress, the pricipal stress, and the displacement on the implant fixtures under the loads were calculated by using the finite element method. Four different types of bicon implant fixture were used for this study. The geometries of implant fixtures to develop the model were used by a sales brochure and profile project. Three-dimensional finite element model of the mandible was developed with 6.0 mm implant in diameter wurrounded by approximately 2.5 mm of bone. Bone densities were classified according to the elastic modulus of the tree. The finite element program MSC PATRAN (MSC, Software Corp., USA) were used for analysis of stress distribution. The value of the Von-Mises stress, the pricipal stress, and the displacement on the implant fixtures under the vertical and inclined loads were decreased when the diameter of implant fixture was increased, and increased when the elastic modulus was decreased. The stress on implant fixture under the vertical and inclined loads was distributed through the length of implant fixtures in D3 and D4. The distribution of stress was influenced by the direction of loads. In the wide diameter of implants, the stress was developed at outer surface of bone. In conclusion, this study suggest that stress developing on the peri-implant tissues might be influenced by the dimension of implant, elastic modulus of bone, and direction of loads.

• Korean Journal of Ichthyology
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• v.34 no.1
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• pp.16-24
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• 2022

The eggs development and early life history of Sarcocheilichthys variegatus wakiyae was investigated. The adult fishes were collected in Yeongsangang River, Damyang-gun, Jeollanam-do, Korea, and their spawning inducement was carried by sex maturation hormone (Ovaprim) injections. Spawning amount was mean 31±3.5 Mature eggs were cicular in shape and mean 2.40±0.05 mm in diameter. Hatching period of the embryo was 230 to 240 hours after fertilization under water temperature of 22℃. The newly hatched larvae were 10.7±0.19 mm in total length (TL). 3 days after hatching, postlarvae was measured 12.0±0.13 mm in TL and the tip of the caudal fin was bent at 45°. 11 days after hatching, it was measured 14.6±0.13 mm in TL, and transferred to juvenile as the number of fins (iii7 dorsal fin, iii6 anal fin, i7 ventral fins) reached a constant number of each part.

• Korean Journal of Ichthyology
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• v.23 no.3
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• pp.217-224
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• 2011

The seven leptocephali (14.6~68.0 mm in total length) of the family Ophichthidae, from the East Sea of Korea, were identified using 12S rRNA 861-bp sequences and their morphological development were described. Our seven leptocephali were identified to Echelus uropterus based on genetic distance (d=0.000) being well consistent with that of adult E. uropterus. Our seven leptocephali of E. uropterus are characterized by morphological combinations: caudal fin present; the melanophores present in series of nine gut swellings; total myomeres 154~158; body depth in total length less than 10%; eight black horizontal bands present from anus to caudal fin base. Our morphological and molecular results suggest that E. uropterus may be an intermediate group between subfamily Ophichthinae and Myrophinae.