• Journal of Mechanical Science and Technology
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• 제20권11호
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• pp.1993-2001
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• 2006

The piezoelectric bimorph film, which, as an actuator, can generate more effective displacement than the usual PVDF film, is used to control the turbulent boundary-layer flow. The change of wall pressures inside the turbulent boundary layer is observed by using the multi-channel microphone array flush-mounted on the surface when actuation at the non-dimensional frequency $f_b^+$:=0.008 and 0.028 is applied to the turbulent boundary layer. The wall pressure characteristics by the actuation to produce local displacement are more dominantly influenced by the size of the actuator module than the actuation frequency. The movement of large-scale turbulent structures to the upper layer is found to be the main mechanism of the reduction in the wall- pressure energy spectrum when the 700$700{\nu}/u_{\tau}$-long bimorph film is periodically actuated at the non- dimensional frequency $f_b^+$:=0.008 and 0.028. The biomorph actuator is triggered with the time delay for the active forcing at a single frequency when a 1/8' pressure-type, pin-holed microphone sensor detects the large-amplitude pressure event by the turbulent spot. The wall-pressure energy in the late-transitional boundary layer is partially reduced near the convection wavenumber by the open-loop control based on the large amplitude event.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.90-95
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• 2005

Most of mechanical structures are composed of many substructures connected to one another by various types of mechanical joints with various shapes of cutouts. It is important to study these connected structures under dynamic forces for evaluation of stress concentration. In this paper, a FQI(fatigue quality index) analysis using the concept of SF(severity factor) is performed to various shape of elliptical hole. The SF is affected by the location of cutout in plate and radius ratio, static SF is analyzed with finite element analysis and the equation of FQI for predicting a dynamic SF is formed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.60-63
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• 2002

This paper presents bead-based microbiocihps to detect and separate target proteins. Micro beads coated with capture proteins were introduced into a microchamber, and target proteins flowing across the chamber were bound and concentrated. The chip was connected with an external fluid system. Bead surfaces were double-coated with photo-cleavable linkers and capture proteins. The proteins bound on the beads were photo-separated under UV irradiation, and excited to be measured in fluorescence. $38{\sim}50{\mu}m$ sized polystyrene beads were used. SOGs(silicon-on-glass) were used to fabricate the microchip having glasses bonded on both sides. 100 ${\mu}m$ thick silicon channel was formed through silicon deep RIE process. The upper glass cover had holed through to have inlets and outlets fabricated by powder-blastings. In this study, biotin and streptavidin were used as capture proteins and detection proteins, respectively. The protein mixtures of streptavidin, HSA(human serum albumin) and ovalbumin were applied for selective detection test.

• 한국추진공학회지
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• 제8권3호
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• pp.10-16
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• 2004

원통 다발형 그레인의 연소시험 결과 저주파 불안정 현상이 나타났다. 그 원인은 원통 그레인 내면의 압력과 외면의 압력차(압력 비평형)가 주원인임을 알 수 있었으며, 그레인 반경방향으로 홀을 뚫어 그레인 내면에 상승된 압력을 외면으로 빠르게 확산되도록 하여 안정된 연소현상을 얻을 수 있었다. 그러나 고온 조건에서도 안정된 연소 현상을 얻기 위하여 직경 3mm 흘 7개를 뚫게 됨에 따라 가스발생량의 증가가 많이 둔화되어 격자를 사용하는 방법을 연구하게 되었다. 격자를 사용함으로써 큰 와류(large vorticity)를 소멸시켜 그레인에 홀을 뚫지 않고도 안정된 연소를 얻을 수 있었으며 가스 발생량도 점진적으로 증가시킬 수 있었다. 가로${\times}$세로 격자는 5${\times}$5, 그레인은 격자에 고정시키지 않을 때 가장 좋은 결과를 얻을 수 있었다.

• 박물관보존과학
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• 제9권
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• pp.95-104
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• 2008

광주 신창동 유적에서 출토된 목제 유물에 대해 수종분석 37점, 칠분석 3점등총 40점에 대하여 분석하였다. 결과 목제품에 사용된 수종은 상수리나무류, 벚나무류, 살구나무류, 오리나무류, 단풍나무류, 버드나무류, 사시나무류 등으로 총 7종이 식별되었으며, 특히 칠기와 접시 같은 생활용품의 경우에는 모두 산공재 수종을 사용하였다. 칠도막 분석 결과 유공칠기와 통형칠기 동체부 5는 칠한 횟수에서 차이가 있지만 밑칠을 칠한 후 맨 상층에 흑색안료와 칠을 혼합하여 칠하였으며, 5절판은 토분과 흑색안료를 칠과 혼합하여 밑칠을 한 후에 상층에 흑색안료를 혼합한 칠을 칠한 것으로 확인되었다.

• 대한수의학회지
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• 제34권2호
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• pp.219-227
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• 1994

The development of abomasum in fetuses between 60, 90, 120 days of gestation and neonates of Korean native goats was investigated by light, scanning and transmission electron microscopy. The results obtained were summarized as follows ; 1. The abomasum wall appeared to be differentiated into the epithelium, lamina propria, muscle layer, and serosa at 60 days of gestation. The epithelium was stratified columnar and these nuclei were located near the apical two thirds portion of the cell at 60 days of gestation, and then transformed into simple columnar epithelium with the flat basal nuclei. 2. The inner circular and outer longitudinal muscle layers were observed at 90 days of gestation and the blood vessels had become quite well developed as various arterioles, venules and capillaries of different size during this age. 3. Gastric pits were seen at 90 days of gestation and continued gradually to increase depth during gestation. 4. The mucous, parietal and chief cells appeared in epithelium at 90 days of gestation and continued gradually to increase in number during gestation. In 120 days fetuses and neonates, muscle layer had become very thickeness. 5. Scanning electron microscopically, the inner surface of the abomasum already consisted of wavy spiral folds which had many fine wrinkles at 60 days of gestation. In 90 day old fetuses, each spiral fold was enlarged and its surface was tended to be split into many straight longitudinal ridges and among these ridge were found shallow grooves, At 120 days, the subdivided swellings of ridges were progressively complicated in shape. In the neonates, the inner surface was flat and holed with many gastric pits. 6. Transmission electron microscopically, the epithelium was straified columnar and these nuclei were irregular shape at 60 days fetus. The parietal, chief and mucous cells were observed in 90 day old fetuses and continued gradually to increase in number during gestation. 7. The development of the abomasum was relatively slow at early stages, it was accelerated greatly in the last of gestation.

• 한국안전학회지
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• 제21권1호
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• pp.96-104
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• 2006

This study is to find out how the sawdust-mixed RC beam with holes acts compared to two case of normal one with sawdust without hole, without sawdust. variables are ED3H1, ED3H2, ED3H1UB, ED3H2L, ED5H1, ED5H1UB, ED5H2, ED5H2L, Normal with sawdust PLA without sawdust. All sand, aggregate, cement are in accordance with KS. mixing design is also in accordance with KS and done at D remicon company in order to decrease any error in mixing manually. ED3H1 showed 7tone of maximum load capacity having only minor tensile deformation around hole, compared to the center of the beam. ED5H2L showed almost same shape of tensile strain between hole area and center of two beam length, while having 9.5 tone load capacity, incase of two holes being in the longitudinal axis. But ED5H2 in case of two holes being in same forcing direction showed 8.4tone of load capacity while having minor tensile chape around hole and normal tensile shape in the center of beam length. Two diameter 3cm hole in longitudinal axis give more effective behavior than the other case, practically. Capacity decrease between 5cm and 3cm in eccentric position form the longitudinal axis is less than percents. There is minor capacity difference between hole diameter 3cm hole, but 13tone difference of load capacity between hole diameter 5cm.

• KSBB Journal
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• 제20권2호
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• pp.100-105
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• 2005

탈질화 균주인 Paracoccus denitrificans를 이용한 탈질화 공정에 있어서 탈질 효율의 증대를 위해 선행 연구를 바탕으로 화학적 permeabilization 처리 후 균주를 고정화시키는 방법을 이용하였다. 반응기는 이상적인 CSTR을 도입하여 free cell reactor와 immobilized cell reactor 그리고 permeabilized and immobilized cell reactor의 세 가지 형태의 실험을 실시하였으며, 탈질효율의 비교를 위해 M-M 식을 적용시켰다. 각 반응기의 체류시간에 따른 탈질 효과는 permeabilized and immobilized cell reactor가 가장 우수하였으며 또한 반응 평형에도 다른 두 반응기에 비해 빨리 도달하는 것으로 나타났다.

• 한국응용과학기술학회지
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• 제36권2호
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• pp.448-455
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• 2019

본 연구는 오르막 퍼팅 시 좌, 우 경사에 따른 볼의 움직임이 어떻게 변화되는지에 대해 알아보는 것을 목적으로 한다. 본 연구를 위해 한국프로골프협회에서 15년 이상의 골프경기 경험이 있는 피험자들이 참여하였고, 본인들의 퍼터를 이용하여 실제 그린과 유사한 환경에서 퍼팅 동작을 수행하였다. 비디오 카메라를 이용하여 피험자들의 오르막 그린 경사에 따른 퍼팅 동작을 수집 후 동작분석을 실시하였으며, 통계적 유의수준을 a=.05로 설정하였다. 연구결과로 좌, 우 경사별 오르막 퍼팅에서 볼의 위치가 왼쪽에서 오른쪽으로 위치 할 때 볼 움직임의 속도와 각속도가 증가하는 것이 확인되었으며, 여러 경사도 중 성공률을 높여야 하는 오르막 퍼팅에서 경사에 따른 어드레스 볼 위치를 변화할 때, 임팩트 시 클럽 페이스와 볼 움직임이 어떻게 변화하는지를 검증하고, 현장적용 측면에 도움을 주는 과학적 자료를 제시하고자 본 연구를 진행하였다.

• Composites Research
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• 제21권4호
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• pp.15-21
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• 2008

단일 탄소섬유에 부착된 반구형 미소본드 시험편을 제사하여 에폭시수지와 난소섬유사이의 계면전단강도를 평가하였다. 반구형 미소시험편의 경우, 드랍레트 미소접합시험편 및 역반구형 미소접합시험편과 비교하여 계면강도측정값들이 높은 회귀계수 및 삭은 편차를 보여주었다. 이는반구형 시험편의 메니스커스 부분이 다른 미소시험편보다 작으며 핀홀 부하장치의 선단과 접촉하고 있는 수지부분에서 응력집중이 감소했기 때인 것으로 사료된다. 이들 시험에 대한 유한요소해석결과, 반구형시험편에서는 수지/섬유의 계면부를 따라 전단응력분포가 응력모드의 전환이 없이 안정하였다. 또한 이들 계면강도 측정데이터는 미소 바이스의 선단과 핀홀 판의 선단과 같은 부하장치의 종류에 따라 달라졌음을 알았다.