• 소성∙가공
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• 제8권4호
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• pp.356-363
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• 1999

This paper discusses some techniques for the determination of optimum blank size and pre-form design for multi-stepped deep drawing of oval shell. The deep drawing process of oval shape has been regarded as more difficult than that of cylindrical shell because of its complicated behavior of plastic deformation. But there is insufficient information in this area to carry out successful deep drawing work of irregular products such as oval, rectangular, and square shapes. In order to find the optimum conditions, the drawing apparatus for two kinds of pre-form design are built, a series of drawing experiments performed, and thickness stain distributions measured. From the results of thess suggested experiments, various optimum process variables are observed and discussed.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.15-22
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• 2002

Considering the high temperature durability, the most important issue is to accurately predict the maximum operating temperature of the shell, mat and substrate. This temperature prediction then defines the material selections far the mat, shell and cones, and allows an assessment to be made as to the necessity of heat shielding. In this papers, The commercial code FLUENT was utilized to simulate automotive oval type catalytic converters, with the objective of predicting thermal behavior under steady-state, high-load conditions. Specialized computational models are used to account for effects of heat and mass transfer in the monolith, conjugate heat transfer in the various converter materials, and radiation heat transfer.

• International Journal of Industrial Entomology and Biomaterials
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• 제25권2호
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• pp.205-208
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• 2012

Antheraea pernyi silkworm is a well known wild silkworm to produce a valuable silk fiber. A. pernyi silkworm was reared in Korean oak field and examined the cocoon characteristics, such as cocoon weight, cocoon shell weight, and percentage of cocoon shell weight. Degumming loss was also measured after alkali degumming process. A. pernyi silkworm spins tawny color cocoon in oval shape. Cocoon shell weight of A. pernyi silkworm, 0.78 g, was heavier than that of B. mori silkworm, 0.51 to 0.63 g. Cocoon shell percentage of A. pernyi silkworm, 32.8%, was higher than that of B. mori silkworm, 23.4 to 25.2%. Degumming loss percentage of A. pernyi silkworm, 17.1%, was lower than that of B. mori silkworm, 25.0%. SEM showed that the surface of the cocoon filament was coarse and oriented with longitudinal direction.

• 한국정밀공학회지
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• 제25권3호
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• pp.115-125
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• 2008

Recently, Exhaust Gas Recirculation (EGR) system which re-flow a cooled exhaust gas from vehicles burning diesel as fuel to a combustion chamber of engine has been used to solve the serious air pollution. For the design and mass production of EGR system, it is essential to ensure structural integrity evaluation. The EGR system consisted of ten dimpled oval core rectangular tubes, two fix-plates, two coolant pipes, shell body and two flanges in this study. To confirm the safety of the designed system, finite element modeling about each component such as the dimpled oval core tube with the dimpled shape and others was carried out. The reliability of EGR system against exhaust gas flow with high temperature was investigated by flow and pressure analysis in the system. Also, thermal and strength analysis were verified the safety of EGR system against temperature change in the shell and tubes. Furthermore, modal analysis using ANSYS was also performed. From the results of FE analysis, there were confirmed that EGR system was safe against the flow of exhaust gas, temperature change in EGR system and vibration on operation condition, respectively.

• 한국패류학회지
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• 제27권3호
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• pp.191-192
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• 2011

Pulmonate snail, Onchidium hongkongensis from muddy flat of Muan-gun was recorded as new to the Korean molluscan fauna. Shell-less body light-gray or reddish-gray in colour, oval shaped with numerous pustules on dorsal surface usually covered with mud. Black pair of tentacles with terminal eyes. Including the new record in this study, the family Onchidiidae 2 genera and 2 species in the Korean waters.

• 한국패류학회지
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• 제31권3호
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• pp.253-255
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• 2015

The family Olividae includes predatory species with medium-sized, glossy, elongated oval-shaped shell. As sand-dwellers, they are broadly distributed in tropical and subtropical oceans. They feed mostly on other mollusks and carrions including sea snails and bivalves. To date, two species in the genus Amalda (subfamily Ancillinae) have been reported in Korean waters. In this study, Amalda rubiginosa (Swainson, 1823) was collected from Korean waters and morphologically described in details as a first record.

• 한국수산과학회지
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• 제5권1호
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• pp.17-22
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• 1972

본 시험은 일본 Miyagi Ken 굴 연구소에서 1969년 채묘된 O. lurida 및 C. angulata를 항공편으로 우송하여 1970년 1월 20일부터 12월까지 경남 거제군 하청면 연구리 옥계지선에서 수하식으로 성육시켜 조사한 것이며 그 결과는 다음과 같다. 1. O. lurida는 평균 각고 36.4mm 각장 29,5mm인 둥근모양으로서 소형굴로 자랐고, C. angulata는 각고 87.4mm, 각장 52.3mm인 타원형으로서 대형굴 형태로 성장했다. 2. O. lurida, C. angulata는 다같이 수온이 $16^{\circ}C$ 이상일 때 6, 7월시에 성장도가 좋았으며, 이때의 비중은 $1.01717\~1.02368$ 사이였다. 3. 각고 각장간의 상대적인 변화는 O. lurida는 년간 큰 차가 없었으나, C. angulata는 7월에서부터 현저한 차를 이루어 11월에 35.8mm로 그 차가 가장 컸다. 4. 치사율은 O. lurida는 $35.2\%$였으며, C. angulata는 $21.7\%$를 나타냈다.

• 한국패류학회지
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• 제15권2호
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• pp.115-119
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• 1999

We investigated the processes of egg and larval developments for aquaculture technique development of seedling production fo the flat oyster, Ostrea denselamellosa. Teo flat oyster of larviparous type was different from the pacific oyser (ovivarous type) because their larvae (trochophore and prodissoconch larvae) in the gill released into the seawater. The process of egg development was observed by artificial fertilization at $25^{\circ}C$, using a dissecting method. The sizes of Unfertilized eggs ranged from 80 to 90 $\mu\textrm{m}$ and fertilized eggs with globule-shape was 90-100 $\mu\textrm{m}$. The Polar body appeared after fertilization and egg cleavage began within 1 hour, reaching the blastula stage after 10 hours. The trochophore in the gill appeared 2-3 days after fertilization and grew to the prodissoconch larvae (130 140 $\mu\textrm{m}$) having a complete shell after 1-2 days. The shell of prodissoconch larvae grew to 205 220 $\mu\textrm{m}$ after 10 hours, and then they became umbo stage larvae showing oval in shape. The velum of umbo stage larvae was degenerated about 17-20 days after fertilization and grew into a pediveliger with a developed foot, at this time, the shell length size was 320 360 $\mu\textrm{m}$.

• International Journal of Industrial Entomology and Biomaterials
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• 제2권2호
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• pp.111-117
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• 2001

Screening of fifteen bivoltine silkworm breeds of Bombyx mori Linn at a temperature of $31{\pm}1^{\circ}C$ and relative humidity of 85${\pm}$5% resulted in the identification of eight thermo-tolerant breeds. The survival and cocoon shell ratio of the tolerant breeds ranged from 72.7 to 78.7% and 20.0 to 20.1% respectively. The tolerant breeds comprised of four oval breeds and four dumb-bell breeds. Eight foundation crosses prepared by crossing the oval and dumb-bell parents among themselves were screened at a temperature of $31{\pm}1^{\circ}C$ and relative humidity of 85{\pm}5%. The performance of the foundation crosses on 11 economic characters were analysed by employing Multipie Trait Evaluation Index method. Four foundation crosses which scored average index value > 50 were selected as breeding parents and breeding initiated for the evolution of thermo-tolerant bivoltine silkworm breeds. The methodology and the results of the foundation crosses reared both at 31{\pm}1$^{\circ}C$ and at $25{\pm}1^{\circ}C$ temperatures, are discussed.

• 한국산학기술학회논문지
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• 제10권12호
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• pp.3971-3976
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• 2009

본 연구에서는 버려지는 굴패각을 상수도관 내부의 부식방지를 위한 세라믹 코팅제의 원료물질로 활용하고자 굴패각의 물리화학적 특성 및 소성가공 특성에 관한 연구를 수행하였다. 굴패각은 92.08%가 탄산칼슘($CaCO_3$)으로 이루어져 있었으며, 분쇄된 굴패각 입자의 형태는 대부분 타원형 형태를 나타내었다. 그리고 소성 처리된 굴패각의 특성은 소성온도가 높고 소성시간이 경과할수록 무게감소량 및 칼슘함량이 증가하는 경향을 나타내어 소성온도를 높이고 입자크기를 작고 균일하게 할수록 소성가공이 효율적인 것으로 나타났다. 이에 소성가공 처리된 굴패각은 정수장 및 상하수도관의 내부 부식방지를 위한 세라믹 코팅제의 원료물질로써 재활용이 가능할 것으로 판단하였다.