• Korean Journal of Ichthyology
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• v.23 no.3
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• pp.246-249
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• 2011

Twenty five specimens (40.8~58.4 mm SL) of Gymnogobius taranetzi (Family Gobiidae) were collected from the estuary of Samcheok-si and Yangyang-gun, Gangwon-do, Korea. This species is distinguished from other Gymnogobius species by oculoscapular canals not extending anteriorly through interorbital space, but replaced by rows of sensory papillae; oculoscapular canal pore C is absent; some yellow bands on body in female with breeding color. The new Korean name "Dong-hae-nal-mang-duk" is proposed for this species.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.55-63
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• 2019

This study was conducted to evaluate animal welfare approved farms in three housing systems (open, windowless, and free-range). The survey was conducted in 25 animal welfare approved farms, and 10 farms were surveyed for distribution status. The main breed in all animal welfare approved farms of laying hens was Hy-Line Brown variety. In the case of open house, laying hens were bred in traditional and panel houses simultaneously; however, the ratio of panel house was 58.3%, which was higher than that of the traditional house. All the windowless houses were made of panels and more than 15,000 laying hens were housed in a single windowless house. In the case of free-range house, it was maintained on a small scale of less than 12,000 birds. Fifty-six percent of the surveyed farms were breeding at $7{\sim}8birds/m^2$. In terms of male and female ratios, most farms maintained 1 male:15 females, but there was a farmhouse that switched 17 or 20 females to 1 male. The daily dietary allowance was 110~170 g, and 32% of the surveyed farms provided feed of more than 150 g/day, which showed that forage feed was important. The age of at the first egg was 123 days, 122 days, and 120 days, and the peak percent was 91.8%, 94.9%, and 86.5% in open, windowless and free-range houses, respectively. The average egg production rate was 74.0%, 84.6%, and 72.7% in open, windowless, and free-range houses respectively, thus, there was no correlation between feed intake and hen-housed eggs. Distribution of welfare certified eggs was mainly a direct deal with the consumer or through contract production. The ratio of direct transactions between large-scale marts and eco-friendly specialty stores of welfare approved eggs was higher than that of conventional eggs. The rate of contract sales of eggs in both the barn and free-range systems was high, and the percentage of courier sales farms was also high. Excluding courier services, price of eggs in the barn system rose to more than 30 won/egg in the second half of 2017 (after AI). Price of eggs in the free-range system rose to more than 50 won/egg in the second half of 2017 (after AI). In the case of courier sales, the same price of 500 won was maintained before and after AI. In conclusion, the results of this study can be used as basic data for improving the animal welfare certification system for laying hens in Korea.

• Korean Journal of Ichthyology
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• v.25 no.4
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• pp.216-221
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• 2013

Histological study and gonadosomatic index (GSI) to investigate an exact reproductive cycle of Korean loach Kichulchoia multifasciata, were conducted throughout a year from December 2011 to December 2012. The stage of ovarian and testicular development was divided into four phases: a growing phase (November to March the following year), a spawning phase (April~May), a degeneration phase (May~June), a resting phase (June to November). The peak of the spawning period in male and female appears between April to May, having water temperature $12.7^{\circ}C$ and day length over 13 hours. These results were consistent well with a histological study.

• The Korean Journal of Malacology
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• v.13 no.2
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• pp.131-141
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• 1997

전북 김제시 심포에서 1994년 1월부터 12월까지 월별로 채집된 백합 Meretrix lusoria의 생식세포형성과정 및 생식주기를 , 조직학적으로 조사한 결과는 다음과 같다. 백합은 자웅이체이고 난생을 하며, 생식소는 내장낭의 간중장선의 하부로부터 족부의 근육부근까지 분포하며, 성숙되면 팽대되지만 방란, 방정 후에는 위축된다. 생식소는 많은 난자형성여포들과 정자형셩여포들로 구성되어 있다. 여포에는 호산성 세포와 미분화간충직들이 들어 있는데, 이들은 초기 생식세포의 영양물질로 제공되고 있으며, 생식소가 발달함에 따라 점차 소실된다. 초기활성기의 난원세포는 직경 10$\mu\textrm{m}$ 내외이며, 초기 난모세포는 난병을 여포벽에 부착한 채 성장을 하여 70$\mu\textrm{m}$ 내외의 완숙란으로 된다. 정원세포가 성장을 하여 정보세포, 정세포를 거쳐 변태를 마친 정자는, 정자형성소낭의 중앙 내강에 정자속을 형성한다. 방란, 방정을 마친 생식소는, 일부 미방출된 생식세포가 퇴화 흡수되면서 비활성기를 지나 이듬해 수온상승과 더불어 새로운 발달을 시작한다. 생식주기는 연속적인 5단계로 구분할 수 있는데, 초기 활성기(1-3월), 후기 활성디 (2-5월), 완숙기(4-8월), 부분 방출기(6-9월), 퇴화 및 비활성기(9-2월)로 구분할 수 있다. 산란은 6월 (22$^{\circ}C$)부터 9월 ($25^{\circ}C$)까지 지속되지만, 산란성기는 7월(27$^{\circ}C$)-8월(28$^{\circ}C$)이다. 생식소지수는 1월에 0.58을 나타내며 5월에 4.60으로 최대값을 나타낸 후, 6월부터 점차 감소하기 시작하여 12월과 1월에는 1.0미만에 머무른다.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.5
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• pp.88-96
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• 2017

As a part of the development procedures of scramjet engine with a regenerative cooling system, this experiment was performed using air-assist type injectors for scramjet engine. Two types of injectors were used in this experiment with the 90 and 60 degrees of the injection angle to the main flow. Mie-scattering was used for spray visualization and PDPA was used for the measurement of the atomization characteristics. It was found that increasing the pressure of supplied gas and the distance from nozzle tip led to the enhancement atomization characteristics and the injector with 60 degrees injection angle has better atomization characteristics than 90 degrees injector.

• Composites Research
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• v.14 no.3
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• pp.18-31
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• 2001

Interfacial and microfailure properties of the modified steel, carbon and glass fibers/cement composites were investigated using electro-pullout test under tensile and compressive tests with acoustic emission (AE). The hand-sanded steel composite exhibited higher interfacial shear strength (IFSS) than the untreated and even neoalkoxy zirconate (Zr) treated steel fiber composites. This might be due to the enhanced mechanical interlocking, compared to possible hydrogen or covalent bonds. During curing process, the contact resistivity decreased rapidly at the initial stage and then showed a level-off. Comparing to the untreated case, the contact resistivity of either Zr-treated or hand-sanded steel fiber composites increased to the infinity at latter stage. The number of AE signals of hand-sanded steel fiber composite was much more than those of the untreated and Zr-treated cases due to many interlayer failure signals. AE waveforms for pullout and frictional signals of the hand-sanded composite are larger than those of the untreated case. For dual matrix composite (DMC), AE energy and waveform under compressive loading were much higher and larger than those under tensile loading, due to brittle but well-enduring ceramic nature against compressive stress. Vertical multicrack exhibits fur glass fiber composite under tensile test, whereas buckling failure appeared under compressive loading. Electro-micromechanical technique with AE can be used as an efficient nondestructive (NDT) method to evaluate the interfacial and microfailure mechanisms for conductive fibers/brittle and nontransparent cement composites.

• Korean Journal of Ichthyology
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• v.30 no.1
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• pp.9-17
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• 2018

This study investigated how the larvae of three winter-spawning fishes are adapted in a cold water environment by examining the morphology, digestive system, and swimming ability of larvae from three winter-spawning species (Gadus macrocephalus, Liparis tanakae, Hexagrammos agrammus). Data were collected at hatching and first feeding. The results were compared with repored data on several non-winter-spawning species. Mean total lengths at hatching (${\pm}SD$) were $4.35{\pm}0.11mm$, $5.26{\pm}0.08mm$, and $7.48{\pm}0.35mm$ for G. macrocephalus, L. tanakae, and H. agrammus, respectively. Three winter-spawning fishes had well-developed digestive tracts after hatching than those of non-winter-spawning fish larvae. Yolks were intact until 5 days post-hatching in all three species, indicating that they had longer mixed-feeding periods compared with fishes spawned during other seasons. G. macrocephalus, L. tanakae, and H. agrammus larvae had superior cruise and burst speeds (measures of swimming ability) than non-winter-spawning larvae. We conclude that the unique characteristics of these three winter-spawning species are naturally selected adaptations under lower water temperature in winter.

• The Korean Journal of Rheology
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• v.10 no.2
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• pp.65-73
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• 1998

본연구에서는poystyrene-block-poly (ethlene-co-butylene)-block-polystyrene(SEBS) 삼중블록 공중합체와 저분자량 단일중합체인 Hercotac 1149 (H1149)의 70/30 (w/w) 혼합물 의 미세상분리와 그동력학을 유변물성 측정법과 SAXS 실험을 통하여 연구해 보았다. 먼저 혼합물의 미세상분리 온도를 유변물성 측정법과 SAXS 실험을 통해 각각구한 다음 샘플을 미세상분리 온도보다 높은 온도에서 그이하의 온도로 급냉시킨 후 유변물성과 산란강도의 사간에 따른 변화로부터 미세상분리 동력학에 대한 정보를 구하였다. 이렇게 얻어진 데이터 를 Avrami 형태의 핵생성 성장(NG) 메커니즘으로 해석해 보았는데 최대산란강도 Imax 뿐만 아니라 저장 점탄성계수 G＇과 손실 점탄성계수 G＂의 시간에 따른 변화를 잘 예측할수 있 었다. 한편 서로다른 두 time-resolved 실험으로부터 Avrami 플롯을 그려서 구해진 Avrami 변수들은 같은 급냉 깊이에서는 서로 잘 일치함을 확인하였다. 반감기는 급냉 깊이가 증가 함에 따라 점차 감소하는 경향을 보였는데 이는 급냉 깊이가 클수록 미세상분리가 더 빨리 진행되고 있음을 보여주는 것이다. 또한 Avrami 지수는 급냉 깊이가 증가함에 따라 3에서 4로 급격히 변했는데 이로부터 급냉 깊이가 작을 때에는 70/30 (w/w) SEBS/H1149 혼합물 의 미세상분리가 불균일 핵생성 성장 메커니즘에 따라 진행되고 급냉 깊이가 더 커지면 미 세상분리가 스피노달 상분리 메커니즘으로 변하고 있음을 예측할수 있었다.

• Korean Journal of Ichthyology
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• v.34 no.4
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• pp.270-276
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• 2022

In 2020 and 2022, the habitat of brown trout (Salmo trutta) was investigated in the Soyanggang River in Chuncheon, Gangwon province. As a result of the fish survey, A total of 43 individuals brown trout were identified. The total length of brown trout was widely confirmed from 60 cm or more to less than 10 cm. In January 2020, sperm release and spawn were observed in male and female confirmed at the St. 1. Brown trout were identified stably settled in the Soyanggang River and continues to live. In addition, benthic macroinvertebrates that can act as food sources of brown trout and abundantly inhabited. The riverbed structure is evenly composed of fine gravel and gravel, which constitutes the conditions necessary for habitat and spawning. However, the spawning grounds, spawned eggs and hatched fry have not yet been clearly identified, so continuous research is needed.

• Korean journal of applied entomology
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• v.43 no.3 s.136
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• pp.225-231
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• 2004

An endoparasitoid wasp, Cotesia plutellae, has been used for a biological control agent against the diamondback moth, Plutellae xylostella. It has a symbiotic polydnavirus in their reproductive tract, which is required for its successful parasitization. Here, we measured a specific replication time of the polydnavirus during female development of C. plutellae. We, also, analyzed the reproductive potentials of female C. plutellae under mating or different host conditions. At $25^{\circ}C$, pupal C. plutellae began to develop adult tissues such as compound eyes and wings since day 2. At day 5, all adult tissues including antennae were developed and were ready to emerge. With polyclonal antibody raised against C. plutellae polydnavirus, an immunobloting could confirm virus replication at day 4 during pupal stage. Virus particles could be visualized by transmission electron microscope in the oviduct lumen of day 5 pupae. After adult eclosion, venom gland and ovarian calyx increased in size, though ovarioles did not. Mated females layed large number of eggs (over $60\%$) at first 4 days during their mean longevity of ca. 8 days at $25^{\circ}C$. Unmated females showed less active ovipositional behavior, where all the eggs developed into males. C. Plutellae parasitized both P. xylostella and fall webworm, Hyphantria cunea. However, C. Plutellae developed faster and showed higher successful paarasitization in P. xylostella than in H. cunea.