• 한국해양학회지
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• v.4 no.1
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• pp.17-35
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• 1969

This work concerns morphological studies of the Japaness jack mackerel, Trachurus japonicus(Temminck & Schlegel). A total of 48 random samples consisting of 2669 fish is examined, representing three geographic regions, namely, Kamakura, Nagasaki, and Tottori. Preservation affects length and weight of fish considerably, but the variability after 10 days is shown to be negligible. The variability in measuring the morphometric characters due to different measures and orders is found to be significant. They are relatively small, however, compared to the variability in mean length to be expected in samples drawn from the population. Two meristic characters, namely, anal and second dorsal fin rays and three morphometric characters, namely, head length, first and second dorsal insertion distances are chosen for the study. Results of the statistical analysis reveal that differences in the selected meristic characters among samples within and between regions are found to be significant. In general, it is reasonable to state that the jack mackerel collected in Nagasaki region, on the average, have greatest number of anal fin ray and second dorsal fin ray followed by Kamakura, and Tottori regions in that order. It is found that although no significant differences in the slope of regression line are noticed, the mean differences of the selected morphometric measurements in relation to fish length are found to be significant among samples within each region. Differences in the regression coefficients as well as the adjusted sample means are found to be significant between regions. The analysis suggests that samples from Nagasaki region, on the average, have longest head length and greatest distances from snout to the insertion of first dorsal and second dorsal fins followed by Kamakura, and Tottori regions in that order.

• International Journal of Air-Conditioning and Refrigeration
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• v.16 no.3
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• pp.83-88
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• 2008

A geometrically asymmetric trapezoidal fin is analyzed using the one-dimensional analytic method. Heat loss and thermal resistance are represented as a function of the fin base thickness, base height, fm shape factor, inside fluid convection characteristic number, convection characteristic numbers ratio, fm length and ambient convection characteristic number. The relationship between the fin base height and the shape factor for equal amounts of heat loss is presented. One of the results shows that the variations of the fm base thickness and the inside fluid convection characteristic number give no effect on the thermal resistance.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.2 no.2
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• pp.97-109
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• 1998

A comparison of the two dimensional heat loss, computed using the analytical method and the finite difference method in two models(i.e. one is a parabolic fin whose parabolic curves meet at the fin center line and the other is a transformed parabolic fin whose tip cuts vertically), is made assuming the analytical method is correct. For these methods, the root temperature and surrounding convection coefficients of these fins are assumed as constants. The results show that the relative errors of the heat loss between the two methods for the parabolic fin whose tip cuts vertically are smaller than those for the one whose tip does not cut. In case of Bi=0.01, the values of the heat loss obtained using a finite difference method are close to those values obtained using the analytical method for both models. The values of the heat loss from both models calculated by using the analytical method are almost the same for given range of non-dimensional fin length in case of Bi = 0.01 and 0.1.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.225-233
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• 1975

Morphological changes of early post-larval and young stages of Chasmichthys dolichognathus HILGEnDORF (Family Gobiidae) have been studied based on the samples of 953 individuals collected in June 1968, July 1969 and July 1971. Particular emphasis was paid on the development of fin rays, chromatophore patterns and ventral fins. The primordial fin rays of the first dorsal fin appear in the post-larvae of around 8.0 mm in total length, and dorsal fin fully develops in the larvae of around 9.2 mm. In the early young stages of 17.0 mm in total length fin rays have completely developed. According to chromatophore patterns the larvae are grouped into three successive groups. The larvae at the early stages of 6.3-14.2 mm have melanophores on the whole dorsal surface, the posterior ventro-lateral part of the tail and the basal part of the caudal fin. In the later larval stages of 17.0-24.4 mm a group of melanophores are added on medio-lateral part of the tail. These melanophores extend anteriorly and eventually cover the medio-lateral part of the whole body. In the early young stages of 97.2-34.8 mm the chromatophores cover the whole body surface in cloudy and H-shaped patterns. The chromatophore patterns of this stage are distinctive as generic characters of the fish. Fin membranes of the ventral fin appear in the post-larval stage (ca. 7.4 mm), and the primordial fin rays develop in the late post-larval stages (ca. 14.2 mm). The fin rays develop into a complete sucker in the young fish stage of around 30.0 mm in total length.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1177-1181
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• 2009

Heat loss from a convective rectangular profile annular fin with variable inside fluid heat transfer coefficient and fin height is calculated by using both the one dimensional analytic method and two dimensional variables separation method. Heat loss from the two dimensional method and the relative error of heat loss between the one dimensional method and two dimensional method are presented as a function of the fin length, ambient convection characteristic number and fin height. One of the results shows that the relative error of heat loss between one dimensional method and two dimensional method is within 0.7% in the range of given parameters in this study.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.12
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• pp.654-659
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• 2013

This paper presents a numerical optimization of louvered fins to enhance the JF factor in terms of the design parameters, including the fin pitch, the number of louvers, the louver angle, the fin thickness, and the re-direction louver length. We carried out a parametric study to select the three most important parameters affecting the JF factor, which were the fin pitch, number of louvers, and the louver angle. We optimally designed the louvered fin by using 3rd-order full factorial design, the kriging method, and a micro genetic algorithm. Consequently, the JF factor of the optimum model increased by 16% compared to that of the base model. Moreover, the optimum model reduced the pressure drop by 17% with a comparable heat transfer rate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.203-208
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• 2020

This study was carried out to clarify the larvae and juveniles of egg development and autonomous development of Hemibarbus longirostris from Korea, and to obtain basic data for species conservation and seed production. The shape of the egg was circular and sticky. The average size of the eggs was 2.01 mm (n=10). At 185 hours after fertilization, more than 50% of the total embryos were hatched. The newly hatched larvae had an average total length of 8.10 mm (n=5) and had egg yolk in the abdomen. At 3 days after hatching, the larvae absorbed all egg yolk was average total length 8.64 mm. On the 6 days after hatching, the caudal tip of the notochord started to curve upwards was average total length 10.9 mm. At 70 days after hatching, the average total length 37.9 mm. The number of fins was i 8-10 in dorsal fin, iii 7 in the anal fin, and ii 5 in the ventral fin.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.2
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• pp.76-81
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• 2007

Threshold voltage ($V_{th}$) modeling of doublegate (DG) MOSFETs was performed, for the first time, by considering barrier lowering in the short channel devices. As the gate length of DG MOSFETs scales down, the overlapped charge-sharing length ($x_h$) in the channel which is related to the barrier lowering becomes very important. A fitting parameter ${\delta}_w$ was introduced semi-empirically with the fin body width and body doping concentration for higher accuracy. The $V_{th}$ model predicted well the $V_{th}$ behavior with fin body thickness, body doping concentration, and gate length. Our compact model makes an accurate $V_{th}$ prediction of DG devices with the gate length up to 20-nm.

• Development and Reproduction
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• v.24 no.4
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• pp.307-316
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• 2020

The purpose of this study is to observe the early life history of Korean Lefua costata and use the result as basic taxonomic research data for balitorid fish. The fertilized eggs were light green color with completely circle shape and mean size was 1.21±0.06 mm (n=30). Immediately after hatching, the size of the larvae was 2.81±0.11 mm (n=5) in mean length, with egg yolk. On the 3rd day after hatching, the preflexion larvae had a mean length of 4.64±0.09 mm (n=5), and their mouth was opened to start feeding. On the 8th day after hatching, a mean length of the postflexion larvae was 9.43±0.46 mm (n=5), the distal part of the notochord was bent to 45°, and 16 fin rays were developed on the caudal fin. On the 31st day after hatching, a mean length of juveniles was 22.3±0.85 mm (n=5), and the number of fin rays was the same as that of adult fish with (iv8) dorsal fins and (iii8) anal fins.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1076-1079
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• 1993

A fuzzy digital controller is combined an autopilot system for compensating the cross coupling effect of the induced roll due to the dynamic characteristic of three fin torpedo. However the utilization of fuzzy chip has many interfacing problems with typical microprocessors of the guidance and control unit. Since a fuzzy digital controller on a microprocessor uses a finite word length A/D converters arul D/A converters, ADC and DAC may generate nonlinear effects such as deadband and limit cycle phenomena. In this paper, the robustness of fuzzy digital controller is tested with ADC a finite word length.