• 한국작물학회지
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• 제42권4호
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• pp.446-451
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• 1997

한국 재래종 옥수수의 염색체 특성을 알아보기 위하여 재래종 옥수수 10개의 자식계통 C-banding법으로 염색하고 염색체상에 존재하는 heterochromatic knob 수를 조사한 결과는 다음과 같았다. 1. Knob수는 6∼12개이었고 평균 9.0개이었으며 계통별로 차이가 있었다. 2. 염색체의 장완과 단완의 비율, 상대적 길이 등을 비교해 보기 위하여 Waesungri와 PI213-749 두 계통을 조사해 본 결과 계통별로 차이가 있었다. 즉, 장완과 단완의 비율은 2번 염색체의 경우에만 1.25로서 동일하였고 다른 염색체의 경우는 모두가 다르게 나타났다. 염색체의 상대적 길이는 일반적으로 Waesungri에서 크게 나타났는데 1번 염색체의 경우 Waesungri에서는 223이었고 PI213749에서는 192이었다. 3. 염색체의 상대적 길이, 장완과 단완의 비율, 그리고 knob의 위치 등을 나타내는 모식도를 통하여 두 계통의 염색체 특성을 보다 명확하게 비교할 수 있었다.

• 한국항공우주학회지
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• 제45권5호
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• pp.359-366
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• 2017

본 논문에서는 가오리 연의 비행 중에 형성되는 모든 받음각 변화를 고려한 풍동 실험을 통해 가오리연의 공력 자료를 구축하였다. 이 공력 자료로부터 가오리연이 받음각 또는 연실-지평각이 변함에 따라 평형 비행 상태를 이루는데 필요한 목줄에 대한 꽁수줄의 상대적 길이를 해석하였다. 해석 결과 목줄에 대한 꽁수줄의 상대적 길이는 연의 시위 길이와 풍속에 전적으로 의존하고 받음각에 따라 모핑 변화하고 있음을 알 수 있었다. 본 자료를 활용하면 비행환경과 연의 자세에 맞게 방줄의 상대길이를 조정할 수 있으며 최적성능을 유지하는 연을 다룰 수 있게 될 것이다.

• 수산해양기술연구
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• 제50권3호
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• pp.396-406
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• 2014

Shrimp beam trawl fishery is one of the important coastal fisheries in Korea. It has a regulation to the length of beam (8m) and wing net (7m) of shrimp beam trawl that has been used in the district of Junlanam-do and Gyungsangnam-do. This regulation was made in relation to the size of shrimp beam trawler of 3-ton class at that time. Now the shrimp beam fishing vessel has a limit not greater than 5 tons in gross ton. Recently, with improvement of fishing industry and fishing vessel fishermen asked the expansion of the length of beam and wing net, therefore it is necessary to investigate the effect of lengthening the beam and wing net length. Three different beams (8m, 10m and 12m in length) and three different wing net (7m, 10m and 13m in length) were made and the experiment was conducted near Narodo of Goheng by two fishing vessels of 4.98 and 4.88 tons in gross ton between June 2011 and October 2012. When the length of wing net was increased from 7m to 10m and 13m, the relative catch ratio in total biomass was increased 25% and 79% for shrimp, (17% and 22% in total), respectively. And when the beam length was increased from 8m to 10m and 12m, the relative catch ratio was increased 35% and 84% for shrimp, (21% and 37% in total), respectively. The force exerted to the iron guide of inhauler's with the beam length of 8m was about 30% greater than that with the beam length of 10m when hauling the shrimp beam trawl net.

• 한국융합학회논문지
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• 제7권4호
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• pp.181-190
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• 2016

The objective of this study is to find the effective stiffness and compressive strengths of a unit-cell pinwheel truss and double pinwheel truss model designed following a double helical geometry similar to that of the DNA (deoxyribonucleic acid) structure in biology. The ideal solution for their derived relative density is correlated with a ratio of the truss thickness and length. To validate the relative stiffness or relative strength, ABAQUS software is used for the computational model analysis on five models having a different size of truss diameter from 1mm to 5mm. Applied material properties are stainless steel type 304. The boundary conditions applied were fixed bottom and 5 mm downward displacement. It was assumed that the width, length, and height are all equal. Consequently, it is found that the truss model has a lower effective stiffness and a lower effective yielding strength.

• 한국전산유체공학회지
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• 제21권3호
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• pp.31-38
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• 2016

The FDS-HCIB method is expanded to simulate water-oil-air flows around oil booms under relative motion, which is intended to increase the thickness of contained oil. The FDS scheme captures discontinuity in the density field and abrupt change of the tangential velocity across an interface without smearing. The HCIB method handles relative motions of thin oil booms with ease. To validate the developed FDS-HCIB code for water-oil-air flow around a moving body, the computed results are compared with the reported experimental results on the shape, length, and thickness of the oil slicks under towing. It is observed that the increase in pressure field between two barriers lifts the oil slick and the interfacial wave propagates and reflects as one barrier gets closer to the other barrier.

• The Korean Journal of Ecology
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• 제6권2호
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• pp.106-113
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• 1983

The growth of Korean axolotl., Hynobius leechii, was analyzed in natural water as control group and in six copper ion groups contaminated by 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 ppm of copper ion. The copper ion checks the growth of the axolotl. The axolotl was not survived during 30 days in the copper ion of 0.3ppm, and, in the 0.4ppm the axolotl was not survived during 10 days after hatch. The growth of head width and body length show a convexing increase pattern, while that of hind leg shows a concaving increase pattern. The copper ion checks the development of hind leg. In the growth quantity of head width, body length and hid leg, that of natural water show the most rapid increase pattern, and copper ion groups of 0.1, 0.2, 0.3ppm follow in that order. The coefficient of relative growth($\alpha$) of control group is the greater value, and the copper ion groups of 0.1, 0.2, 0.3ppm follow in that order. The contaminated groups show the negative allometry in the relative growth of the containated groups to the natural water. Body length shows positive allometry, while hind leg shows negative allometry in the relative growth to head width.

• 수산해양기술연구
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• 제53권4호
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• pp.317-326
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• 2017

Comparative fishing experiments were conducted in the eastern coastal waters near Uljin, Korea from 2002 to 2004, using the experimental trammel nets to estimate the selectivity for spinyhead sculpin Dasycottus setiger. The inner panels of the nets were made of nylon monofilament with four mesh sizes (82.2, 89.4, 104.8, and 120.2 mm) while its two outer panels were made of twisted nylon multifilament with a mesh size of 510 mm. The SELECT (Share Each Length's Catch Total) procedure with maximum likelihood method was applied to obtain a master selection curve. The different functional models (normal, lognormal, bi-normal, and logistic model) were fitted to the catch data. The lognormal model with the fixed relative fishing intensity was chosen as the best-fitted selection curve through comparison of model deviance and AIC (Akaike's Information Criterion). The optimum relative length (the ratio of fish total length to mesh size) with the maximum relative efficiency was obtained as 2.492.

• 한국산림과학회지
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• 제97권5호
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• pp.485-491
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• 2008

This study was performed in 14 unthinned Mongolian pine (Pinus sylvestris L. var. mongolica Litvin) plantations in northeast China. Data were collected on 70 sample trees of different canopy position with diameter at breast height (DBH) ranging from 6.9 cm to 34.5 cm. Diameter and length of knots per whorl below the living crown were studied by different vertical levels divided by relative knot height (RHK) in this paper. Models taking DBH and height to the crown base (HCB) as independent variables were developed to predict knot diameter (KD) in a sample whorl. According to the vertical distribution tendency and range of sound knot length (KLsound), KLsound was modeled as multiple linear function of DBH, KD and relative knot height (RHK). The loose knot length (KLloose) was described as a function of DBH, KD and height above the ground for knots (HK) in a mixed log-linear model. Results from this study can provide abundant knot information so as to describe the knot size and vertical distribution tendency of Mongolian pine plantation.

• 한국가금학회지
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• 제13권2호
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• pp.167-172
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• 1986

본 연구는 단관백백레그혼순계 염색체의 형태적 특징과 크기를 명확히 구명하기 위하여 중심입지수, 등 완비 및 상대적 길이를 측정하여 이용하고 이들의 염색체 수를 밝혔다. 시험재료로서는 서울대학교 부속목장에서 사육중인 단관백색레그혼순계 암컷 20수와 수컷 5수를 공시하고 이들을 수정시켜 50개의 수정란에 대하여 염색체 분석을 하였다. 분석방법으로서는 중기상의 포착을 위하여 colchicine을 이용하고, hypotonic, fixation, air-drying 처리를 하여 나타난 초기 metaphase상으로서 핵형분석하였다. 시험 결과 분석된 각 염색체의 형태적 특징은 다음과 같다. 1. 1,2심 염색체 : meta 및 submetacentric으로서 이들 둘 간에는 크기에 따라 명확히 구분된다. 2. 3,4심 염색체 : 길이는 서로 비슷하나, 4심 염색체에서는 짧은 단완이 나타나고, 3심은 acrocentric 형태이다. 3. 5심 염색체 : 성염색체(Z)로서 metacentric 형태이다. W 염색체 역시 metacentric 이지만 7-8심 염색체 크기 정도이다. 4. 6심 염색체 : 3심과 같이 acro 형체이나 3심 염색체 크기의 반정도이다. 5. 7,8심 염색체 : 6심 크기의 반정도로서 길이는 서로 비슷하나 7심은 짧은 단완을 가지고, 8심은 acrocentric 염색체이다. 6. 9심 염색체 : 7심과 8심의 크기와 비슷하나 metacentric 양상이다. 7. 나머지 30쌍의 소형염색체 : 점의 형태로서 대부분 acrocentric 형태이다. 이 밖에도 염색체의 수에 있어서 관찰된 sample의 58%가 78개로 나타났고, 나머지는 72-77개로 나타남에 따라 이의 염색체 수는 최소 78개로 사료된다.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2203-2208
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• 2006

Both 1-D and 2-D analytic methods are used for a rectangular fin optimization. Optimum heat loss is taken as 98% of the maximum heat loss. Temperature profile using 2-D analytic method and relative error of temperature along the fin length between 1-D and 2-D analytic methods are presented. Increasing rate of the optimum heat loss with the variation of Biot number and decreasing rate of that with the variation of the fin base length are listed. Optimum fin tip length using 2-D analytic method and relative error of that between 1-D and 2-D analytic methods are presented as a function of Biot numbers ratio.