• Korean Journal of Ichthyology
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• v.31 no.4
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• pp.249-254
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• 2019

One specimen of Albula argentea (296.3 mm in standard length), belonging to the family Albulidae, was collected in a set net in the coastal waters of Jejudo Island, Korea. As the adult A. argentea has not been caught from Korean waters, we described its morphological characters based on the collected specimen and compared them with those of the previous reports on A. argentea and A. koreaus. As a result, the present specimen was characterized by having 68~73 pored lateral line scales (vs. 77~78 for A. koreana), 72~73 vertebrae pored lateral line scales (vs. 77~80) and none streak on the check (vs. yellowish streak). Molecular analysis using the mitochondrial cytochrome b DNA sequences was also conducted to confirm the correctness of species identification and taxonomic status of the sample.

• Smart Structures and Systems
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• v.29 no.5
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• pp.705-714
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• 2022

In this paper, the effect of magnetic field on the vibration behavior of a Magnetorheological elastomer (MRE) sandwich MEMS actuated by electrostatic actuation with conductive skins are examined within the multiple scales (MMS) perturbation method. Magnetorheological smart materials have been widely used in vibration control of various systems due to their mechanical properties change under the influence of different magnetic fields. To investigate the vibrational behavior of the movable electrode, the Euler-Bernoulli beam theory, as well as Hamilton's principle is used to derive the equations and the related boundary conditions governing the dynamic behavior of the system are applied. The results of this study show that by placing the Magnetorheological elastomer core in the movable electrode and applying different magnetic fields on it, its natural vibrational frequency can be affected so that by increasing the applied magnetic field, the system's natural frequency increases. Also, the effect of various factors such as the electric potential difference between two electrodes, changes in the thickness of the core and the skins, electrode length, the distance between two electrodes and also change in vibration modes of the system on natural frequencies have been investigated.

• Journal of The Korean Association For Science Education
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• v.20 no.1
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• pp.1-11
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• 2000

This study investigated both elementary and middle school students' abilities of reading scales and students' conceptions of measuring instruments and units. Seventy two students with 5th grade, sixty nine students with 7th grade, and eighty students with 9th grade were participated. Performance tests and written questionnaires were used. To assess their scale reading abilities, individual performance test was used. Every student should measure length of an envelope, temperature of water, volume of water, etc. And to find out students' conceptions related with measuring instruments and units, written questionnaires with pictures and photographs were used. Some of the students' abilities of reading scales were considerably poor. The results of a two-plate-balance and measuring-cylinder were worse than those of a ruler, a spring-balance, and a thermometer. Many of the students had misconceptions related with measuring instruments. Some of them did not know exactly the meaning of volume, or mass, or force. So they did not know what to measure with the measuring instruments. Also students were confused with several units of volume, force, weight and mass.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.132-138
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• 1984

The genus Squalidus of Korea, formerly regarded as genus Gnathopogon is reviewed and keys to following 4 species and subspecies: S. gracilis majimae, S. chankaensis tsuchigae, S. chankaensis ssp., and S. japonicus coreanus. The genus spualidus is distinguished from genus Gnathopogon by the position of snout, color pattern on the body sides, number of scales above lateral line, and distance from anus to anal finorgin. G. majimae Jordan et Hubbs is junior synonym of S. gracilis majimae, and G. coreanus (not Berg) is splitted and identified as S. chankaensis tsuchigae, S. c. ssp., and S. japonicus coreanus. S. c. tsuchigae is very similar to S. j. coreanus, but the eye diameter, barbel length, and the number of lateral line scales are useful characters in separating these species. S. thankaensis ssp. occurring only in the Yongdok-Oship River differs from S. chankaensis tsuchigae in the number of lateral line scales, eye diameter and their body size.

• Journal of architectural history
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• v.14 no.3 s.43
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• pp.119-128
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• 2005

In ancient times, architectural design was seen as a critical task in building technologies. Specifically, form, dimension and structural design are of significant. These aspects are associated with each other and to be emerged as a whole. Designing plan dimension was deemed to be the core of design technology due to its close relationship with module system. Thus, its evolution as well as development process typically represents and reflects the spirits and contents of design technologies in ancient China. In China, the materials regarding ancient architectural technology include Yingzaofashi(營造法式) of Song Dynasty and Gongchengzuofazeli(工程做法則例) of Qing Dynasty. They show many aspects concerning materials, structure, scale system and building. In Yingzaofashi, although the length of objects are decided by 'cai(材)' and 'fen(分)', there are no regulations on length, width and height of a building. However, in the construction of ancient buildings, the above mentioned basic scales are very important in both design and construction. The present paper attempts to discuss the significance, namely, the design principles of length, with and height of ancient chinese architecture.

• Development and Reproduction
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• v.23 no.2
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• pp.161-170
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• 2019

The purpose of this study is to investigate the development of Coreoleuciscus splendidus egg and larvae morphology in the Ungcheon-stream. C. splendidus eggs were round and ranged in size from 1.86-2.01 mm (mean $1.91{\pm}0.14mm$). Immediately after hatching, the larvae had egg yolk in the abdomen with a total length of 5.27-6.63 mm (mean $5.95{\pm}0.96mm$). On the 10 days after hatching, the latter was 8.44-8.65 mm (mean $8.54{\pm}0.14mm$) in total length, and 5 dorsal fin rays were formed in dorsal fin and 8 caudal fin soft rays were formed in caudal fin. At 88 days after hatching, total length was 26.2-25.7 mm (mean $25.9{\pm}0.35mm$), and scales were formed throughout the body. The fin rays of each part were iii.7 in dorsal fin and iii.6 in anal fin, and finally the external form was the same as the adult fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.3
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• pp.154-160
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• 1970

The present paper deals with the growth of yellow croaker by scale age reading. This study is based on material from 596 specimens caught by the Danish seine in the Yellow Sea during the period from June 1967 to April 1968. Ring marks of the scale were formed from April to July, corresponding to the spawning season of the fish reported by Bae (1960). Growth rate of each radius of the ring was approximately 0.73. The relationship between the total length and radius of scales, and the relationship between the body weight and total length are represented by the following equations respectively: L=61.350R+50.184 $$W=4.298L^{3.227}\times10^{-3}$$ Maximum total length calculated by the diagram of Walford's growth transformation, $$L_{n+1}=0.6866L_n+10.8730$$, was 346.9mm. Growth curve of the fish can be expressed by the following von Bertalanffy's equation : $$L_t=346.9(1-e^{-0.376(t+0.609)})$$

• Korean Journal of Ichthyology
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• v.23 no.4
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• pp.269-277
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• 2011

Age and growth pattern of Pacific cod Gadus macrocephalus were determined using samples collected in Jinhae Bay in Korea during the spawning period from 2006 to 2009. The ages of 333 specimens were estimated using their otoliths. The reliability of scales as a means of age determination was analyzed by comparing the ages estimated from otoliths and scales of 96 specimens. The scales collected from the base of the second dorsal fin or from the caudal peduncle were proved to be suitable for age determination of Pacific cod. Monthly changes in the marginal index in otoliths decreased from December showing the lowest value in February. Ages ranged from 4 to 6 years for both females and males, and most of them were 6 years old. Relationships between the otolith radius (R) and total length (TL) were TL=10.4R+3.1 for males, and TL=11.5R+3.4 for females. The growth curves in total length ($L_t$, cm) were expressed as $L_t$=141.5 [1-exp{-0.089 (t+0.209)}] for males and $L_t$=127.5 [1-exp {-0.124 (t+0.077)}] for females.

• Korean Journal of Community Nutrition
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• v.2 no.1
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• pp.3-12
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• 1997

One-to three -month-old infants(n=252) were compared their growth performance(weight, length, head circumference, chest circumference) by feeding methods in cross-sectional study. There were two groups : breast-fed(BF) and formula-fed groups(FF). The weights of infants at 1, 2, and 3 postpartum month were 4.50$\pm$0.48kg, 5.76$\pm$0.62kg and 6.67$\pm$0.68kg, respectively. The weigh of male infants was higher than females. The length were 53.7$\pm$2.6cm, 57.4$\pm$3.3cm, 61.1$\pm$3.1cm at one to three postpartum months, respectively. The length of male infants was higher than females, too. Overall there were no significant differences between feeding methods in weight, length, head and chest circumferences, and monthly weight and length velocity. But 3-month-old formula-fed male infants showed bigger significantly in weight, monthly weight velocity and chest circumference than the breast-feds. By Korean standards, weight-for-height Z-score were distributed from 0 to ＋2. Not only was there a few malnourished infants but also overnourished were noticed, especially in formula-fed group. From this survey, long-time survey on growth and development of large scales might be necessary to determine the effect of feeding methods of infants after 3 months and to set proper grwoth standard for infant. And it was suggested the that the careful attention of polarized nutritional problems of early infants was needed, especially in formula-fed group. (Korean J Community Nutrition 2(1) : 3~12, 1997)

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.3
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• pp.305-314
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• 2001

A modified model is proposed for calculation of transitional boundary layer flows. In order to develop the eddy viscosity model for the problem, the flow is divided into three regions; namely, pre-transition region, transition region and fully turbulent region. The pre-transition eddy-viscosity is formulated by extending the mixing length concept. In the transition region, the eddy-viscosity model employs two length scales, i.e., pre-transition length scale and turbulent length scale pertaining to the regions upstream and the downstream, respectively, and a universal model of stream-wise intermittency variation is used as a function bridging the pre-transition region and the fully turbulent region. The proposed model is applied to calculate three benchmark cases of the transitional boundary layer flows with different free-stream turbulent intensity (1%∼6%) under zero-pressure gradient. It was found that the profiles of mean velocity and turbulent intensity, local maximum of velocity fluctuations, their locations as well as the stream-wise variation of integral properties such as skin friction, shape factor and maximum velocity fluctuations are very satisfactorily predicted throughout the flow regions.