• 산업기술연구
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• 제19권
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• pp.59-65
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• 1999

This study is to analyze turbulent flow over a backward-facing step in a rectangular duct. The side wall effects on the internal flow were determined by varying the aspect ratio(defined as the step span-to-height ratio) from 1 to 20. In the flow behind a backward-facing step, separation, recirculation and redeveloping is occurred frequently. These phenomena appear in a particular variation by varying the aspect ratio. The results show that the aspect ratio has an influence on the velocity and reattachment length. When the AR is increased, the reattachment length is increased. For 6 over aspect ration, the rate of increase is decreased. The length of recirculation in the upper corner is increased, as the increase of aspect ration. It's width is not changed in the variation of aspect ration. The transverse, streamwise and spanwise velocities were decreased along the flow down stream of the step.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권2호
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• pp.217-223
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• 1996

In order to evaluate the changes before and after secondary operations in the patients with cleft lip objectively using full face photographs, the author analyzed results of improvement on nasal width and mouth width and asymmetry of nostril. 1. The ration of asymmetry of thenostril is changed from average 1.24 preoperatively to average 1.08 postoperaively : 61.2% is improved postoperatively. 2. The ratio of nasal width compared with intermedial canthal distance is changed from average 1.15 preoperatively to average 1.10 postoperatively : 3.8% is reduced posteroperatively. 3. The ratio of mouth width compared with intermedial canthal distance is changed from average 1.08 preoperatively to average 1.03 postoperathvely : 4.1% is reduced posteroperatively.

• 한국잠사곤충학회지
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• 제39권2호
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• pp.174-179
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• 1997

The larval head capsule width, larval weight and length of mulberry longicorn beetle, Apriona germari Hope were measured when the larvae were exuviated in artificial diet rearing. The larval head capsule width from the 1st to the 12th instar was ranged from 0.12 to 0.69 cm, and growth ratio of each instar was significantly high between the 1st and the 2nd instars. The fitness to Dyar's law for the larval head capsule width was 87.6%. When the logarithum of the larval head capsule width is plotted against the number of instars, the calculated regression line was LogY=0.12086+0.06998X and Dyar's constant was 1.18. The larval weight was increased with larval developmental stages, and the coefficient of variation of larval weight was apparently high. But the calculated regression line was LogY=-0.91592+0.25959X and Dyar's constant was 1.25. The growth ration of the larval length was clearly high between the 2nd and the 3rd instars, and that of larvae from the 4th instar was decreased. The calculated regression line was LogY=-0.16932+0.09841X and Dyar's constant was 1.25. In conclusion, our results suggested that the larvae growth of mulberry longicorn beetle appeared to be highly related in the larval head capsule width, larval weight and length.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.214-220
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• 1999

In order to use effectively a machinery part with fillet, it is necessary to determine a proper fillet shape in design step, Study of such problem by fracture mechanical criterion is rare. So, this paper focuses on the design of fillet radius in fracture mechanical aspect. Finite element method was used to obtain crack tip stress intensity factor. Stress intensity factor was calculated by COD(crack opening displacement0method proposed by Ingraffea and Manu. The parameter used in this study are thickness ration, filet radium and crack length . If fillet radius increase , crack propagation may be accelerated. Critical crack length is inversely proportional to fillet radius.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.154-159
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• 1995

To achieve a high aspect ration of metal contact, buried contact solar cell scribe the silicon surface using laser. The Q-switched NdLYAG laser which has 1.064$\mu\textrm{m}$ wavelength use for silicon scribing with 25~40$\mu\textrm{m}$ width and 20~200$\mu\textrm{m}$ depth capabilities. The 2~3% shading losses are very low campared to the screen printing solar cell. In this paper, we investigate the silicon scribing theory and pratice, scribing system for BCSC processing.

• Asian-Australasian Journal of Animal Sciences
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• 제21권12호
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• pp.1745-1752
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• 2008

This study was conducted to compare the growth performance and carcass evaluation of Jeju native cattle (JNC) and its crossbreds (CBK = 25 JNC: 50 Charolais: 25 Brahman and BCBK = 62.5 JNC: 25 Charolais: 12.5 Brahman) fed for a short fattening period. Eight male calves each of JNC (80.$40{\pm}10$), CBK ($113.50{\pm}12.3$), and BCBK ($100.3{\pm}9.5$) were weaned at 4 month of age and were fed similar diets for 18 months of their age. All animals were fed a growing ration until 12 months of age and thereafter switched to a fattening ration for a period of 6 months. Final body weight (BW) and BW gain were significantly higher in CBK and BCBK compared with JNC. The CBK and BCBK gained 27.42% and 25.99% more BW, respectively, compared with JNC. The CBK and BCBK animals consumed significantly less DM than JNC to gain a unit of BW. Body weight gain, DM intake and feed conversion efficiency were similar between CBK and BCBK. Weight of hot and cold carcass, ribs, boneless meat and Longissimus dorsi muscle area were significantly different among JNC and its crossbreds. The heaviest carcass was observed in CBK followed by BCBK and JNC. Carcass, chest and femur lengths were greater in CBK and BCBK compared with JNC. Chest width, chest depth and hip width were similar in JNC and its crossbreds. Femur width was significantly greater in CBK compared with BCBK and JNC. Femur depth and chest girth were significantly greater in CBK and BCBK compared with JNC. Weight and fat yield in different carcass cuts were greater in crossbreds compared to JNC. Percent moisture, crude ash, and crude protein of meat were similar in JNC and its crossbreds. Percent crude fat in beef was significantly greater in JNC compared with its crossbreds. Beef shear force value, percent water holding capacity, juiciness and tenderness were significantly greater for JNC compared to its crossbreds. In conclusion, CBK and BCBK have shown greater growth rates and produced heavier carcasses with good degree of fatness when compared with JNC.

• 한국자기학회지
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• 제7권2호
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• pp.97-102
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• 1997

자기헤드의 오프트랙 성능은 하드디스크 드라이브에서 트랙 피치를 결정하는데 사용되고 오프트랙 성능이 트랙 피치에 관한 함수가 747 곡선이다. 본 논문에서는 747 곡선을 컴퓨터를 이용하여 시뮬레이션 하였다. 헤드의 측면재생과 기록변수는 3차원 유한요소법을 이용한 자장해석을 이용하여 구하였고, 신호대 잡음비 (signal to noise ratio : SNR) 계산을 위한 헤드의 재생 신호와 잡음은 가역정리를 이용하여 구하였다. 생성된 747 곡선에 의하면, 소거밴드의 폭이 클수록 또한 유효 신호대 잡음비 SNR$_{eff}$이 작을 수록 오프트랙의 성능이 향상되었다. 기록된 트랙폭이 4.1 .mu. m 인 평면 실리콘 헤드를 사용하여 시뮬레이션으로 생성된 747 곡선과 스핀 스탠드 (spin stand)로 측정된 747 곡선을 비교했을 때, 두 곡선이 비슷하였으며 이로부터 본 시뮬레이션의 타당성을 입증할 수 있었다.다.

• Journal of Advanced Marine Engineering and Technology
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• 제31권4호
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• pp.385-393
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• 2007

The strength evaluation of the most weakest junction part is required for the safety design of all structures. Most of all. in order to enhance the reliability and safety of the welding part. whose use is the highest, it is very important to establish the efficient structure manufacturing technology by studying and investigating the evaluation of fatigue strength in various environments. This study analyzed the relations of da/dN, and th according to the welding methods of SMAW, FCAW, and SAW. In the stage II. the value of stress intensity factor range was the highest in SMAW welding method of stress ration R=0.1, and appeared under the sequence of FCAW and SAW and as the completion section of stress intensity factor was low, threshold stress intensity factor was lowly formed in da/dN - The fatigue life of each welding method is sensitively worked in high stress ratio. judging from the fact that the width of life reduction increases in the high stress ratio zone compared to the width of life reduction in the low stress ratio zone. In the fatigue limit of welding methods before corrosion. the welding of SMAW and FCAW shows the same fatigue limit compared to Base metal, and SAW holds the lowest fatigue limit value.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2000년도 춘계 학술대회 및 국제 감성공학 심포지움 논문집 Proceeding of the 2000 Spring Conference of KOSES and International Sensibility Ergonomics Symposium
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• pp.133-137
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• 2000

Form-ratio means the ratio of Height/Width/Depth in 3-dimensions. The golden ratio or golden section is included as one of the form-ratio. Kansei Engineering System has some basic design databases. Form-ratio and color are basic design elements and they are very important for designing various products in viewpoint of Kansei Engineering. The subjects evaluate the form-ratios of 3-dimensional cubes and virtual products (refrigerator) with SD-scale kansei words(feelings and images). The golden ration was evaluated as "not beautiful" in refrigerator. We compared with the kansei of cube model and virtual product, and obtained databases of the relationship between the form-ratio and kansei.

• 대한전자공학회논문지
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• 제27권3호
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• pp.1-6
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• 1990

무한히 긴 도체 격자판에 TE파가 입사될 때 스트립위에 유기되는 전류분호를 스펙트럴 영역해서 법과 모먼트법을 이용하여 구한다. 스트립간의 간격이 $0.05{\lambda}{\sim}5{\lambda}$인 격자판에 유기되는 전류분호의 파의 입사각에 따른 변화와 스트립 간격에 대한 스트립폭의 비가 0.4~0.8일때 스트립상의 전류분호 변화를 계산한다. 이 결과의 타당성을 입증하기 위해서 다른 방법에 의한 결과와 비교한다.