• 한국수산과학회지
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• 제50권3호
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• pp.287-295
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• 2017

Egg development and morphological change of larvae of the Sakhalin sole Limanda sakhalinensis were studied by observing specimens obtained in a rearing experiment from fertilized eggs to the juvenile stage. The wild broodstock was collected in January 2010 and kept in a circular water tank (${\O}1.5{\times}1m$) at a temperature of $14.5{\pm}0.5^{\circ}C$. Fertilized eggs ranged from 0.72 to 0.82 mm ($0.77{\pm}0.07mm$, $mean{\pm}SD$) in diameter. The eggs were spherical, transparent and adhesive demersal. The egg yolk was divided from the oocyte 10 min after fertilization (AF), and an embryo was formed in 36 h AF. More than 50% of the eggs hatched within 133 h AF. The mouth and anus did not open until $3.5{\pm}0.25mm$ total length (TL). At 4, days after hatching (AH), the fish became larvae 3.7 to 4.2 mm ($4.0{\pm}0.36mm\;TL$), yolk absorption was completed and the mouth began to open. The left eye moved upward and the nostril moved to the right at 39 days AH. These post-larvae ranged from 8.0 to 9.9 mm TL ($8.9{\pm}1.33mm\;TL$). At 50 days AH, the fish became juveniles ($12.4{\pm}1.20mm\;TL$) There were 70-72 dorsal fin rays, 55-56 anal fin rays, 11 pectoral fin rays, and 6 ventral fin rays and the juveniles adopted a benthic life.

• 치과방사선
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• 제20권2호
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• pp.315-333
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• 1990

This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography (l4 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator(60㎜ in diameter, 20㎝ in length) and rectangular collimator(35㎜ × 44㎜, 40㎝ in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rates of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling techniuqe, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.295-299
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• 2006

The inner-structure bonded(ISB) sheet metal is defined as a composite sheet metal which has middle layer of truss-structure between two skin sheets. The characteristics such as ultra-light weight, high rigidity, high strength, etc are required especially for automobile parts. The characteristic of ISB sheet metal depends on inner-structure pattern or method of bonding. Pyramid type of crimped expanded metal is used for inner-structure and both of resistance welding and adhesive bonding are applied to make a specimen. As a result of compression test, it is appeared that forming limit is 10% reduction in thickness under a load of 8kgf per unit element(one inner-structure). In case of uniaxial tensile test the non-uniform surface integrity rather than the buckling of inner-structure happened at a load of 450kgf, which indicates elongation of 7.2% and thickness reduction of 13%. The eye-inspection method was applied to examine the defects occurring on the specimen during stretch forming. In case of biaxial stretch forming only the non-uniform deformation on the surface of a skin sheet could be observed. The forming limit in stretching of ISB sheet metal with the hemi-spherical punch of 150mm in diameter was 3mm in forming depth and 5% reduction in thickness.

• 한국어류학회지
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• 제19권2호
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• pp.128-131
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• 2007

전장 3.0~650.0 mm의 민어, Miichthys miiuy 209 개체의 두장, 문장, 안와후연장 및 안경을 계측하였다. 측정된 개체들의 모든 두부형질은 전장에 대해 회귀하였고, 머리의 상대크기에 선형으로 증가하였다. 결정계수($r^2$)는 0.9823~0.9916의 범위를 나타내었고, 모두 유의하게 나타났다(P<0.0001). 본 연구에서 사용된 두부형질들은 민어의 성공적인 사육을 위한 개체 및 집단성장사 및 형태 변형을 감지할 수 있는 유용한 지표가 될 수 있으리라 사료된다.

• 한국수산과학회지
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• 제53권4호
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• pp.572-576
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• 2020

As grouper aquaculture production intensifies worldwide, hybrids are increasingly produced to induce heterosis of traits such as rapid growth and strong environmental adaptability. In this study, we compared the morphological characteristics of a hybrid grouper to those of its parent species Epinephelus moara and E. lanceolatus. The coefficients of external and skeletal traits evaluated using soft X-rays did not differ significantly among groups; however, several patterns were detected among measured traits. The body depth (BD), length of caudal peduncle (LCP), and pre-anal fin length (PAL) of the hybrid were the same as those of E. moara, whereas the pre-pectoral fin length (PPL) and interorbital width (IOW) of the hybrid were the same as those of E. lanceolatus. Traits that did not differ significantly among the three groups included pre-dorsal fin length (PDL), pre-ventral fin length (PVL), length of anal fin (LAF), and length of dorsal fin (LDF), whereas the depth of caudal peduncle (DCP) and snout length (SNL) showed intermediate traits, and eye diameter (ED) was significantly smaller in the hybrid. Therefore, intermediate traits such as DCP and SNL and specific traits such as ED may be used as indices for hybrid classification.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.280-280
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• 2014

We report the fabrication and electroluminescent characteristics of GaN/InxGa1-xN microdonut-shaped light-emitting diode (LED) microarrays as variable-color emitters. The diameter, width, height, and period of the GaN microdonuts were controlled by their growth parameters and the geometrical factors of the growth mask patterns. For the fabrication of microdonut LEDs, p-GaN/p-AlxGa1-xN/u-GaN/u-InxGa1-xN heteroepitaxial layers were coated on the entire surface of n-GaN microdonuts. The microdonut LED arrays showed strong light emission, which could be seen with the unaided eye under normal room illumination. Additionally, magnified optical images of microdonut LED arrays exhibited microdonut-shaped light emissions having spatially resolved blue and green colors. Their electroluminescence spectra had two dominant peaks at 460 and 560 nm. With increasing applied voltage, the intensity of the blue emission peak increased much faster than that of the green emission peak, indicating that the color of the LEDs is tunable. We also demonstrated that EL spectra of the devices could be controlled by changing the size of microdonut LEDs. What we want to emphasize here with the microdonut LEDs is that they have additional inner sidewall facets which did not exist for other typical three-dimensional structures including nanopyramids and nanorods, and that InxGa1-xN single quantum well formed on the inner sidewall facets had unique thickness and chemical composition, which generated additional EL color. The origin of the electroluminescence peaks was investigated by structural characterizations and chemical analyses.

• 한국발생생물학회지:발생과생식
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• 제18권1호
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• pp.33-41
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• 2014

We investigated the process of yolk absorption in Korean rose bitterling, Rhodeus uyekii, and determined the changes in its morphometric characteristics. The R. uyekii from 1 days post hatching (DPH) to 21 DPH, the eye diameter (ED) was 5.4 at 5 DPH. Thereafter, the ED/total length (TL) ratio increased to 10.7 at 21 DPH (p<0.05). The yolk length (YL) decreased from 95.4 to 1.1 by 21 DPH, and this rate of decrease was greater than that for any other dimension (p<0.05). 12 morphometric dimensions/TL for the R. uyekii were measured at each sampling day from 21 DPH to 170 DPH. At just hatching, the average TL and BW were $6.1{\pm}0.09mm$ and $4.9{\pm}0.07mg$, respectively. At 53 DPH, the average TL was $12.9{\pm}0.28mm$ and the average BW was $14.7{\pm}0.72mg$; the total length growth equation was $TL=5.507e^{0.038t}$ ($R^2=0.916$). Further, the body weight growth equation was $BW=3.3647e^{0.0296t}$ ($R^2=0.9354$). The dimensions with regard to body depth showed the greatest growth rates in the external characteristics of the fish (p<0.05). The patterns of the morphometric characteristics measured in this study can be classified in three ways. The patterns were shown to be increased (y=0.0992x+12.07, $R^2=0.8333$), decreased (y=-0.0569x+42.029, $R^2=0.8395$) or maintained (y=0.005x+18.263, $R^2=0.3678$) from 21 DPH to 170. These results will provide useful indices for the successful rearing of the R. uyekii.

• Journal of the Korean Wood Science and Technology
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• 제23권2호
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• pp.47-54
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• 1995

This study was to measure the properties of logs and classify them by non-destructive methods. The purpose of this experiment was focused at mensurability of logs by non-destructive methods. The non-destructive instrument, Stress-Wave Timer 239A which was made by Metriguard in U.S.A., was used. The stress wave velocities of log's cross direction were measured and compared with three different methods; 1. with hammer, 2. with hammer and D.B.H. meter, 3. with manufactured instrument. Number of used logs were seven logs, which were classified by naked eye into six groups; very severe rot, severe rot, mild rot & knot, mild rot & check, mild rot, sound log, and in diameter were into three groups; large(57.4cm), medium(36~41.2cm), small(28.9cm) log. The results, which were classified by mensurability with non-destructive methods, were followed; 1. The stress wave velocities were very different between rot and sound log. So it meant the possibility of mensurability of logs by non-destructive method even if high standard error. 2. The stress wave velocities decreased with checks more than with rots, which meant the checks affected speeds more. 3. The stress wave velocities increased with knot. 4. The velocities with manufactured instrument showed lower standard error, so more accurate results than other methods. Especially the required labour decreased from 3~4 to 2 persons. 5. Finally, the mensurability showed more accurate results and made the classification of logs scientific.

• Journal of Biosystems Engineering
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• 제42권3호
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• pp.227-233
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• 2017

Purpose: Morphological properties of soybean roots are important indicators of the vigor of the seed, which determines the survival rate of the seedlings grown. The current vigor test for soybean seeds is manual measurement with the human eye. This study describes an application of a machine vision technique for rapid measurement of soybean seed vigor to replace the time-consuming and labor-intensive conventional method. Methods: A CCD camera was used to obtain color images of seeds during germination. Image processing techniques were used to obtain root segmentation. The various morphological parameters, such as primary root length, total root length, total surface area, average diameter, and branching points of roots were calculated from a root skeleton image using a customized pixel-based image processing algorithm. Results: The measurement accuracy of the machine vision system ranged from 92.6% to 98.8%, with accuracies of 96.2% for primary root length and 96.4% for total root length, compared to manual measurement. The correlation coefficient for each measurement was 0.999 with a standard error of prediction of 1.16 mm for primary root length and 0.97 mm for total root length. Conclusions: The developed machine vision system showed good performance for the morphological measurement of soybean roots. This image analysis algorithm, combined with a simple color camera, can be used as an alternative to the conventional seed vigor test method.

• 한국수산과학회지
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• 제39권5호
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• pp.419-426
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• 2006

This study investigated the ecology and growth of Monostroma nitidum Wittrock in both its natural habitat and the laboratory. The maximum length, width, and weight of M. nitidum in March were 9.0$\pm$4.7 cm, 9.6$\pm$3.6 cm, and 1.52$\pm$1.13 g, respectively. Yellowish-green or yellowish-brown reproductive thalli began to appear in January, and over 80% of the thalli matured by March. The male and female spores were ca. 6 $\mu$m long, and elongate and ovoid in shape. The spores had two flagella and one-eye spot, and tended to swim toward light. Maximum number of spores released from matured thalli was 236 cells/mL after 70 minutes at a light intensity of 100 $\mu$mol/m$^2$/s. The zygote diameter ranged from 3.4-6.0 $\mu$m (mean 4.2 $$m) and increased to 69.8 $\mu$m 14 weeks after culture. The mass release of zoospores was observed from thalli in the dark (3 to 12 days), after 30 min under dry conditions in the shade, at 25$^{\circ}C$, and a light intensity of 100 $\mu$mol/m$^2$/s. The maximum number of zoospores released was 109.8 cells/mL after 60 min of induction. M. nitidum fronds on the net increased to 6.8-7.2 cm in length, and 6.6-8.9 cm in width during the winter.