• 한국해양학회지
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• v.13 no.2
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• pp.26-30
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• 1978

This work concerns morphological studies of Alaska pollak, Theragra chalcogramma(PALLAS), and of the Nogari which is generally known as an immature form of the Alaska pollack. Observations are made to see whether significant differences in the meristic and morphometric characters can be recognized between two groups. Four meristic characters, namely, first anal fin rays, first dorsal fin rays, gill rakers, vertebra and three morphometric characters, namely, head length, snout length, eye diameter are chosen for the study. Results of the analyses reveal that the differences in all the selected meristic characters between Nogari and Alaska pollack are found to be not significant. Differences in the snout length in relation to the head length are found to be not significant . However, the differences in the head length in relation to the body length and the differences in eye diameter in relation to the head length are both found to be significant. In spite of the lack of informations on genetypic variations, it is reasonable to state that the Nogari appears to be a juvenile form of the Alaska pollak, and the differences in certain morphometric measurements between two groups are likely to be associated with the differences in the relative growth rates during the life stages.

• Journal of Mechanical Science and Technology
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• v.20 no.2
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• pp.212-226
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• 2006

This paper is a continuation of the authors' previous work on spiral coil heat exchangers. In the present study, the heat transfer characteristics and the performance of a spirally coiled finned tube heat exchanger under wet-surface conditions are theoretically and experimentally investigated. The test section is a spiral-coil heat exchanger which consists of a steel shell and a spirally coiled tube unit. The spiral-coil unit consists of six layers of concentric spirally coiled finned tubes. Each tube is fabricated by bending a 9.6 mm diameter straight copper tube into a spiral-coil of four turns. The innermost and outermost diameters of each spiral-coil are 145.0 and 350.4 mm, respectively. Aluminium crimped spiral fins with thickness of 0.6 mm and outer diameter of 28.4 mm are placed around the tube. The edge of fin at the inner diameter is corrugated. Air and water are used as working fluids in shell side and tube side, respectively. The experiments are done under dehumidifying conditions. A mathematical model based on the conservation of mass and energy is developed to simulate the flow and heat transfer characteristics of working fluids flowing through the heat exchanger. The results obtained from the present model show reasonable agreement with the experimental data.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.107.1-107.1
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• 2014

We have developed and commercialize a time-of-flight - medium energy ion scattering spectrometry (TOF-MEIS) system (model MEIS-K120). MEIS-K120 adapted a large solid acceptance angle detector that results in high collection efficiency, minimized ion beam damage while maintaining a similar energy resolution. In addition, TOF analyzer regards neutrals same to ions which removes the ion neutralization problems in absolute quantitative analysis. A TOF-MEIS system achieves $7{\times}10^{-3}$ energy resolution by utilizing a pulsed ion beam with a pulse width 350 ps and a TOF delay-line-detector with a time resolution of about 85 ps. TOF-MEIS spectra were obtained using 100 keV $He^+$ ions with an ion beam diameter of $10{\mu}m$ with ion dose $1{\times}10^{16}$ in ordinary experimental condition. Among TOF-MEIS applications, we report the quantitative compositional profiling of 3~5 nm CdSe/ZnS QDs, As depth profile and substitutional As ratio of As implanted/annealed Si, Ionic Critical Dimension (CD) for FinFET, Direct Recoil (DR) analysis of hydrogen in diamond like carbon (DLC) and InxGayZnzOn on glass substrate.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.4
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• pp.414-420
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• 2000

In this paper, evaporation heat transfer characteristics at a inner grooved tube were studied using a new natural refrigerants R-290, R-600a and HCFC refrigerant R-22. Experiments were performed in the inner tube with outside diameter of 12.70mm, having 75 fins with a fin height of 0.25mm. The following results were obtained from this research. On the evaporating heat transfer characteristics, the maximum increment of heat transfer coefficient was found in R-290. Average heat transfer coefficient was obtained the maximum value in R-290 and the minimum value in R-22. It reveals that the natural refrigerant can be used as a substitute for R-22. In the grooved inner tube, 70% of the increment of the heat transfer coefficient was obtained compared to the smooth tube. Comparing the heat transfer coefficient between experimental results and simulation data of other's, the Kandlikar's correlated equation was closely approximated to the author's experimental results in the smooth tube or grooved inner one.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.6
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• pp.789-798
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• 1999

The evaporating heat transfer experiments with refrigerant HCFC 22 are performed for performance evaluation using 4 and 6 kinds of microfin tubes with outer diameter of 9.52mm and 7.0mm, respectively. Used microfin tubes have different shape and number of fins with each other, The experimental results are represented with effects of quality, mass flux and EPR. The evaporating heat transfer characteristics are represented by the existence of not only heat transfer area and turbulence promotion effect but also additional other enhancement mechanism, which are the overflow of the refrigerant over the microfin and microfin arrangement. Microfin tubes having a shape which can give much overflow over the microfin show large evaporating heat transfer coefficients. The effect of refrigerant overflow is much severe in evaporation than condensation. The effect of microfin arrangement is related to overflow effect of the refrigerant over the microfin.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.6
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• pp.774-788
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• 1999

To examine the enhancement mechanism of condensing heat transfer through microfin tube, the condensation experiments with refrigerant HCFC 22 are performed using 4 and 6 kinds of microfin tubes with outer diameter of 9.52mm and 7.0mm, respectively. Used microfin tubes have different shape and number of fins with each other The main heat transfer enhancement mechanism is known to be the enlargement of heat transfer area and turbulence promotion. Together with these main factors, we can find other enhancement factors by the experimental data, which are the overflow of the refrigerant over the microfin and microfin arrangement. The overflow of the refrigerant over the microfin can be analyzed by the geometric shape of the microfin. Microfin tubes having a shape which can give much overflow over the microfin show large condensing heat transfer coefficients. The effect of microfin arrangement is related to the heat transfer resistance of liquid film of refrigerant. The condensing heat transfer coefficients are high for the microfin tube with even distribution of liquid film.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.3
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• pp.324-330
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• 2023

We investigated the relative growth and squamation of larvae and juveniles of cultured Larimichthys polyactis. Analysis of the relative growth of larvae and juveniles showed that their preanal length, head length, eye diameter, body depth, and snout length increased with growth. There was no significant chage in the relative growth. The ratio of preanus length to standard length (SL) increased rapidly until SL was approximately 12 mm, and then increased gradually. Cycloid scales first appeared on the lateral line, progressed to the abdominal cavity at 15.13 mm SL, and expanded to the occipital region, base of pectoral fin, and ventral region of the eye at 17.82 mm SL. At 18.03 mm SL, scales formed on the cheek, and those at the base of pectoral fin and in the abdominal cavity were connected to each other. At 19.06 mm SL, major part of the head was covered by scales, except near the lower jaw. Cycloid scales on the lateral line changed to ctenoid scales at the range of 31.71-32.24 mm SL, and those on the nape changed at the range of 69.02-70.84 mm SL. Our results may help to establish conservation and management strategy for Larimichthys polyactis aquaculture.

• Korean Journal of Ichthyology
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• v.5 no.1
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• pp.85-95
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• 1993

Sexual dimorphism of the matured chum salmon, Onchorhynchus keta, have been studied based on biometrical measurements and osteological characters. Male chum salmon has an elongated and hooked upper jaw and canine-like teeth on the upper and lower jaw. The ratios of snout length (SnL) and upper jaw length (UJ) to head length of male were larger than those of the female, whereas eye diameter (ED) and postorbital part of head (CK) of the male were smaller than those of the female's. The ratios of body depth, caudal peduncle depth, anal fin length and adipose fin length to the standard length (PBL) of the male were also larger than those of the female. On sexual dimolrphism was detected in number of fin rays, gill rakers and pyloric ceaca, where as number of lateral line scales and caudal vertebrae of the female was larger than those of the male. Glossohyal and vomer bones has no sexual difference. The ratio of width to length of supraethmoid bone of the male was larger than that of the female. The ratio of frontal part to posterior part of parasphenoid bone of the male was smaller than that of the female.

• 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.6 no.2
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• pp.93-98
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• 1994

The pipefish Syngnathus schelegeli was reared in the laboratory from May to June 1991 and observed the morphology of eggs and larvae squeezed from the parent fish(male). The diameter of inseminated eggs ranged from 0.72 to 1.01 mm (n=50), and yolk in yellow color were found in the eggs. The newly beared larvae were 10.9 mm in average standard length and had 59~60 myomeres. In 6 days after bearing, the post larvae attained 13.8 mm in average standard length and the low jaw was developed. The larvae of 14.1 mm in average standard length (8 days after bearing) had 40~42 fin rays in dorsal fin, 9 in caudal fin and 13~14 in pectoral fin. The juvenile of 14.7 mm in average standard length (10 days after bearing) had the well elongated snout along with the opercular and caudal fin similar to adult stage's.