• 해양환경안전학회지
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• 제30권2호
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• pp.252-261
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• 2024

수중운동체에는 필수적 기능을 담당하는 함교, 러더와 같은 다양한 부가물들이 장착된다. 이들 부가물과 선체의 접합부에는 유선의 박리로 인해 다양한 와류가 생성된다. 이러한 와류는 수중운동체의 추진기로 유입되어 수중방사소음의 증가와 같은 부정적 효과를 야기해 스텔스 성능의 향상을 위해서는 반드시 저감되어야 한다. 본 연구에서는 부가물과 선체의 접합부에서 생성되는 말발굽와류(HSV)와 뿌리와류(RV)를 저감하는데 효과적인 와류저감장치(VRD)에 대한 설계기준을 도출하였다. 먼저, 접합부 와류의 레이놀즈 상사특성 만족 여부를 분석함으로써 설계기준 도출에 부가물의 제원과 유속의 영향을 레이놀즈수로 대체하였다. 또한 VRD의 형상을 정의하기 위해 베지어 곡선을 활용해 VRD의 3차원 표면을 파라미터화하였다. 이후, 와류저감을 위한 VRD의 설계기준 도출을 위해 다양한 제원의 VRD의 와류저감 성능을 분석함으로써 최적의 길이 대 높이 비율이 선정되었다. 최종적으로 대상 범위의 부가물들에 대해 최적 비율을 만족하는 다양한 크기의 VRD 성능이 비교 분석되었다. 이를 종합하여 임의의 부가물에 대해서도 와류저감 성능을 나타낼 수 있는 VRD의 무차원화 설계기준이 도출되었다.

• 한국해양공학회지
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• 제26권3호
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• pp.1-5
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• 2012

A complex energy saving device has been developed for middle class vessels. The propulsive performance of the developed device is described through a model test. The pre-swirl stator, which recovers the rotational energy of the propeller slipstream, is a well-known energy saving device for large vessels. The pre-swirl stator for a large vessel is usually cast as a part of the stern frame and has a high cost. The manufacture of a cast stator for an existing vessel is almost impossible. The complex device that was developed can be fitted on astern frame by welding. The model tests show a 4-6% efficiency gain for middle class vessels with the developed appendages compared to those with bare hulls.

• Asian-Australasian Journal of Animal Sciences
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• 제24권6호
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• pp.881-887
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• 2011

Feathers are one of the integument appendages that form the outer covering, or plumage, on birds. The goslings hatch with a downy coat of feathers formed in embryonic development. They moult the natal plumage into juvenile feathers between 3-5 weeks of age and than moult that juvenile plumage into adult plumage between 8-11 weeks of age. Feather weight of an adult goose makes up about 6.2% of its total body weight. Heritability of the feather production ability is relatively low ($h^2$ = 0.35). Within species or genotype, the quantity and composition of the plumage are affected by genetics (age, body weight or body surface area, feathering rate, sex) and environmental factors (nutrition and production system, weather, microclimate). After slaughter some 90-220 g marketable feathers can be obtained per goose. The yield of feathers and down from each hand-harvesting amounts to between 80 to 120 g per goose, depending upon the frequency and degree of completeness of the harvesting.

• Animal Systematics, Evolution and Diversity
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• 제23권1호
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• pp.9-20
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• 2007

The complete larval development of Chiromantes haematocheir was obtained by laboratory rearing. Five zoeal and one megalopal stages are described and illustrated in detail. Morphological characteristics of the larvae slightly differ from those of Lee (1988), especially in the setal presence of mouthpart appendages. Seven sesarminid zoeas (Parasesarma acis, Parasesarma pictum, Perisesarma bidens, Sesarmops intermedius, Chiromantes dehaani, Chiromantes haematocheir, and Nanosesarma gordoni) can be distinguished from each other in characters of the carapace spines, the antennal exopod and the fork of telson. A provisional key is first provided to aid the identification of seven sesarminid zoeas in Korea.

• Journal of Advanced Marine Engineering and Technology
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• 제30권1호
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• pp.116-124
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• 2006

A model test was carried out, in order to verify the hydrodynamic performances of public 30 feet class sailing yacht. In the initial design stage, the performances and the running attitude of sail yacht including the hull form and sail plan, appendages were estimated by VPP, from which made the representative test conditions. A new experiment system such as captive model device was composed because the running attitude could be changed by wind conditions. The test results show that the minimum resistance is generated in the heeling 20 degree. which was expected in the initial design stage. It is thought to be the useful informations that the keel has an effects on hydrodynamic forces and resistance differences between the upwind and the downwind condition. Also this paper is associated with the state-of-the-art of calculating sailing yacht performance as this is performed in velocity Prediction program (VPP) The VPP results shows a typical shape of a sailing yacht and the designed yacht has the best performance at 120 degree angle of true wind with 20 knots.

• Journal of Chest Surgery
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• 제15권2호
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• pp.169-173
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• 1982

We have experienced two cases of complicated teratoma in anterior mediastinum. One case, 1-year-old female, has a huge anterior mediastinal teratoma involving almost all of the left pleural cavity with atelectasis of the left lung. The other case, 12-year-old female, has a anterior mediastinal teratoma with fistula between the teratoma and the bronchus of anteromedial basal segment of left lung. The bronchus has a bronchiectatic change with cell infiltration. We performed exploratory thoracotomy with complete excision of tumor mass in both cases and with additional resection of anteromedial basal segment of the left lung due to inflammation and necrosis in latter case. The patients had uneventful postoperative courses and were discharged in good condition. Histopathologic diagnosis of these were benign teratoma consist of skin, skin appendages, cartilage, connective tissue, and gut.

• Journal of Species Research
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• 제5권3호
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• pp.459-462
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• 2016

The branchiobdellidan species Holtodrilus truncatus (Liang, 1963) is reported for the first time in Korea. The genus Holtodrilus Gelder and Brinkhurst, 1990 is monotypic within the family Xironodrilidae, and the genus and family of this species are also new to the Korean fauna. The branchiobdellidan specimens were collected from the exoskeletons of the freshwater atyid shrimp, Neocaridina sp., sampled from the 'Andeok Valley', Jeju-do Province, South Korea. Holtodrilus truncatus is characterized by its terete body form, 7/7 dental formula (with a large medial tooth and three pairs of smaller lateral teeth), and no trunk appendages. In addition, we determined a partial sequence of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene as a DNA barcode marker for H. truncatus. The present study is the first record of the branchiobdellidan occurrence on a non-crayfish host (shrimp) in Korea. To date, seven species (four genera in three families) of branchiobdellidans have been reported in the Korean fauna.

• Journal of Species Research
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• 제6권spc호
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• pp.38-50
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• 2017

This study describes a new species of cytheroid ostracod, Paradoxostoma koreana sp. nov., collected in Korea. In addition, three other cytheroid ostracods, P. setoense Schornikov, 1975, Loxoconcha pulchra Ishizaki, 1968, and Ishizakiella miurensis (Hanai, 1957), are reported with brief descriptions and images. Paradoxostoma setoense and L. pulchra were previously only known from Japan, while I. miurensis was previously reported from Korea. Here, we describe variability in hemipenis morphology observed in the Korean population. The new species is closely related to several East Asian species, but its sister species is P. rhomboideum Okubo, 1977. The primary difference between the new species and P. rhomboideum is morphology of the distal projections of the hemipenis, but minor differences exist in the details of the cheatotaxy of other appendages. This report also provides a list of all East Asian Paradoxostomatidae.

• Animal Systematics, Evolution and Diversity
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• 제32권4호
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• pp.281-292
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• 2016

The genus Sinopoda (Araneae, Sparassidae) from Korea are taxonomically reviewed. As a result, Sinopoda aureola is removed from the synonymy of Sinopoda stellatops and treated as a valid species. In addition, two new species, Sinopoda biguttata sp. nov. and Sinopoda nigrobrunnea sp. nov. are described with accompanying photographs. The new species, S. biguttata sp. nov., can be distinguished from other congeners by the combination of following characteristics: a pair of large ivory patterns near posterior muscle sigilla on opisthosoma; relatively small internal genitalia and long, distally bifurcated fertilization duct. The new species, S. nigrobrunnea sp. nov., can be distinguished from other congeners by the combination of following characteristics: lateral edge of epigyne angled; edge of epigynal pocket linear; glandular appendages perpendicularly directed then curved posteriorly.

• Animal Systematics, Evolution and Diversity
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• nspc9호
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• pp.18-29
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• 2016

An anisogammarid amphipod, Eogammarus possjeticus (Tzvetkova, 1967), is newly recorded from Jindo Island, Korea, with a detailed description and illustrations. The species belonging to the genus Eogammarus are sharing several plesiomorphic characteristics, so they are similar to each other. However, Eogammarus possjeticus can be discriminated from congeners by the following characters combined: appendages are not fossorial, setations of antennae are weak, and the number and position of robust setae on pleonal epimera, urosomes, and telson are different from its congeners. This is the first record of the genus Eogammarus Birstein, 1933 from Korean waters.