• Title/Summary/Keyword: 와도

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Vortex shedding behind the oscillating circular cylinder (진동하는 원형실린더 주위 유동의 와흘림에 관한 연구)

  • Kim, Dae-Hyeong;Kim, Gi-Ha;Lee, Chang-Hun;Choe, Jeong-Il
    • Proceeding of EDISON Challenge
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    • 2013.04a
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    • pp.321-326
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    • 2013
  • 본 연구에서는 원형실린더의 강제 수평 및 수직진동에 따른 와흘림을 관찰하였다. EDISON_CFD의 가상경계법을 이용하여 원형실린더 주위 유동현상을 수치 모사하였다. 원형실린더의 강제 진동 특성에 따른 와흘림 진동수, 공력계수 등의 영향을 분석하였다. 특히, 진동방향에 따른 와흘림의 영향을 분석하여, 원형실린더의 강제 진동에 따른 유동의 선형성을 평가하였다.

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Key Determinants of Online Wine Purchasing Intention (와인의 온라인 구매의 주요 결정요인에 관한 연구)

  • Kang, Sora;Han, Su-Jin;Kim, Yoo-Jung
    • Journal of the Korea Society of Computer and Information
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    • v.18 no.12
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    • pp.123-138
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    • 2013
  • This paper was to figure out why online wine purchasing is not activated despite of the many advantages of having online transactions and to fine key determinants of online wine purchasing intention. Thus, the purpose of this study was to identify the determinants of online wine purchase intention, and examines the relationships between the determinants and online wine purchase intention. Data was collected from those who have experienced in using online wine store to purchase wine, and data was used to test the proposed research model. The findings showed that perceived usefulness and social influence(subjective norm, image) were key determinants of online wine site trust, but they were not related to online wine site trust. It also was found that perceived usefulness, perceived ease of use and subjective norm were positively and significantly related to online wine purchase intention whereas it had no relationship with image. In addition, online wine site trust was shown to influence on online wine purchase intention. Finally, the mediating effects were found in the relationships between perceived usefulness, subjective norm, and online wine purchase intention. Based on the results of the study, implications for future research are drawn.

Triple Labral Lesion of Shoulder - A Case Report - (견관절의 삼중 관절와 순 병변 - 증례 보고 -)

  • Choi, Nam-Yong;Song, Hyun-Seok;Yoon, Jae-Woong
    • Clinics in Shoulder and Elbow
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    • v.12 no.1
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    • pp.80-83
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    • 2009
  • Purpose: A triple labral lesion represents a combination of injuries of the anterior, posterior and superior glenoid labrum. The injury mechanism and symptoms is not completely understood. Materials and Methods: We encountered a triple labral injury in a 39-year-old male complaining pain and active abduction difficulty after a motor vehicle accident. Currently, he does not complain any instability symptoms. The labrum was repaired using bio-absorbable suture anchors and a suture hook. Results: Eighteen months following surgery, the active range of motion was restored and he had no difficulty in his daily activities.

Incidence of Buxtonella sulcata from cattle in Kyonggi-do (경기지방 소의 Buxtonella sulcata 감염 실태)

  • 홍기옥;윤희정
    • Parasites, Hosts and Diseases
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    • v.33 no.2
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    • pp.135-138
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    • 1995
  • In order to survey the prevalence of Buxtonelln sulcatc in Kyonggi-do in 1984 and 1994, the feces of cattle were collected and examined. Of 792 cattle in 1984 and 293 in 1994, cysts of B. sulcata were detected from 266 (33.6%) and 101 (34.5%) cattle respectively. The positive rates were 85.9% and 64.2% in breeder cattle, 44.8% and 9.4% in dairy cattle, 7.5% and 14.9% in Korean cattle and 1.8% in beef cattle. In spring, the cyst positive rates were 62.5% in 1984 and 27.8% in 1994; 20.1% and 66.7% in summer; 21.3% and 0% in autumn; and 34.8% 64.6% in winter. More cattle, 69.1%(184) and 55.5% (56) in 1984 and 1994, had diarrhea among the cyst postive cattle than those of cyst negative, 37.6% (198) and 32.3% (62).

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Development of Analysis Method and Experimental Equipment for Fatigue Durability of Automotive Wire Harness System (자동차 와이어 하네스 피로내구 해석 방법론 및 시험기기 개발)

  • Lee, Heung-Shik
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.3
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    • pp.199-205
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    • 2013
  • In this study, the methodology for the fatigue life prediction using finite element method(FEM) in wire, bundle and assembly level of the wire harness system and the development of the fatigue life test machine for the numerical analysis are investigated. To obtain stress-life(S-N) histories of the componential wires of the system, five kinds of wires are prepared and applied to the repeated bending motion using developed fatigue life test equipment. Equivalent model of the wire from the rule of mixtures theory is used for the material modeling of sheath and wire core combination. Contact conditions among the wires, taping conditions are established through the bundle level test and numerical bundle analysis. Wire and bundle level results are adopted for the assembly level analysis. For the assembly level analysis, real wire harness system including bundle and grommet is numerically modeled and applied contact condition between wires with real opening motion. The fatigue life more than 700,000 cycles of the assembly is obtained from the FEM, and it is confirmed that the result has good agreement with the experimental result.

수직 정렬된 실리콘 와이어 어레이의 제작 방법과 동심원형 p-n 접합 태양전지의 제조 및 동향

  • Kim, Jae-Hyeon;Baek, Seong-Ho;Jang, Hwan-Su;Choe, Ho-Jin;Kim, Seong-Bin
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2010.05a
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    • pp.12.2-12.2
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    • 2010
  • 반도체 소자, 바이오 센서, 태양전지 등에서 집적도 및 소자 성능 향상을 위해서 최근 실리콘 소재를 위주로 한 수직 정렬형 와이어 어레이와 같은 3차원 구조의 소재에 대한 연구가 많이 진행되고 있다. 깊은 반응성 이온 식각법(DRIE: Deep Reactive Ion Etching)과 같은 건식 식각법으로 종횡비가 높은 실리콘 와이어 어레이를 제작할 수 있지만 시간과 공정비용이 많이 소요된다는 단점이 있고 양산성이 없다. 이를 극복하기 위해서 VLS (Vapor-Liquid-Solid)방법이 연구되고 있지만 촉매로 사용되는 금속의 오염으로 인한 소자 성능의 저하를 피할 수가 없다. 본 연구진에서 연구하는 있는 전기화학적 식각법을 사용하면 이러한 문제를 극복하고 매우 정렬이 잘 된 실리콘 와이어 어레이를 제작할 수 있으며 최적 조건을 정립하면 균일하고 재현성 있는 다양한 종횡비의 기판 수직형 실리콘 와이어 어레이를 제작할 수 있다. 또한, 귀금속 촉매 식각법은 금속 촉매를 사용하여 식각을 하지만 VLS 방법과 달리 Top-down 방법을 사용하기 때문에 최종 공정에서 용액에 담구어 귀금속을 식각하여 제거 하면 귀금속 촉매가 실리콘을 오염시키는 일은 배제할 수 있다. 귀금속 촉매 식각법의 경우 사용되는 촉매의 다양화, 포토리소그래피 방법, 그리고 식각 용액의 조성 변화에 따라 다양한 형상의 와이어 어레이를 제작할 수 있으며 이에 대한 결과를 소개하고자 한다. 3차원 실리콘 와이어 어레이를 사용하여 동심원형 p-n접합 와이어 어레이를 제작하면 소수캐리어의 확산거리가 짧아도 짧은 동심원 방향으로 캐리어를 포집할 수 있고 태양광의 입사는 와이어 어레이의 수직 방향이므로 태양광의 흡수도 효율적으로 할 수 있기 때문에 실리콘의 효율 향상을 달성할 수 있다. 이에 대한 본 연구진의 연구결과 및 최근 연구 동향을 발표하고자 한다.

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Study on the Effects of Morphology, Preservation and Reproductive Cycle of In Vitro Developmental Rate of Cats Oocytes (난자의 형태와 난소의 보존 및 채취시기가 고양이 난자의 체외발생에 미치는 영향에 관한 연구)

  • 전연화;이명헌;김상근
    • Journal of Embryo Transfer
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    • v.18 no.2
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    • pp.109-113
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    • 2003
  • The study was carried out to investigate the effects of morphology, preservation and reproductive cycle of oocytes in vitro maturation of cats oocytes and development of IVM embryos. The results were summarized as follows : 1. Nuclear status of GV and MI of in vitro cultured(24 h) oocytes with and whithout cumulus cells were 74.3% and 25.7%, 28.6% and 11.4%, 77.1% and 5.7%, respectively, The rate of oocytes with cumulus cells was higher than that of denuded oocytes. 2. Nuclear status of GV and MI of in vitro cultured(24 h) oocytes recovered from ovaries collected at different stages of the reproductive cycle(inactive, follicular and luteal) were 88.6% and 6.5%, 60.0% and 11.4%, 77.1% and 5.7%, respectively. 3. Nuclear status of fresh and salts-stored oocytes with and whithout cumulus cells were 74.3%, 25.7% and 37.1%, 11.4% and 57.1%, 13.3%, 17.1%, 3.3%, respectively. The rate of oocytes with cumulus cells(13.3%∼74.3%) was higher than that of denuded oocytes(3.3%∼57.1%).

Numerical Investigations of Vorticity Generation in Fully Vegetated Open-Channel Flows (수치모의를 이용한 전단면 식생 수로에서의 와도 생성 분석)

  • Kang, Hyeongsik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.2B
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    • pp.179-189
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    • 2010
  • This paper presents a numerical investigation of vorticity generation in fully vegetated open-channel flows. The Reynolds stress model is used for the turbulence closure. Open-channel flows with rough bed-smooth sidewalls and smooth bed-rough sidewalls are simulated. The computed vectors show that in channel flows with rough bed and rough sidewalls, the free-surface secondary currents become relatively smaller and larger, respectively, compared with that of plain channel flows. Also, open-channel flows over vegetation are simulated. The computed bottom vortex occupies the entire water depth, while the free-surface vortex is reduced. The contours of turbulent anisotropy and Reynolds stress are presented with different density of vegetation. The budget analysis of vorticity equation is carried out to investigate the generation mechanism of secondary currents. The results of the budget analysis show that in plain open-channel flow, the production by anisotropy is important in the vicinity of the wall and free-surface boundaries, and the production by Reynolds stress is important in the region away from the boundaries. However, this rule is not effective in vegetated channel flows. Also, in plain channel flows, the vorticity is generated mainly in the vicinity of the free-surface and the bottom, while in vegetated channel flows, the regions of the bottom and vegetation height are important to generate the vorticity.

Film Thickness Control of Polydimethylsiloxane for Transfer of Si Wire Arrays (실리콘 와이어 어레이 이송를 위한 폴리디메틸실록산 박막 두께 조절)

  • Lee, Sun-Yi;Baek, Seong-Ho;Kim, Jae-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.136-136
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    • 2010
  • 본 연구에서는 귀금속 촉매 식각법을 이용하여 고효율의 태양전지 응용을 위한 p형 실리콘 와이어 어레이를 제조 하였다. 실리콘 와이어 어레이를 기판에서 분리하기 위해 고무 상의 고분자인 폴리디메틸실록산 (polydimethylsiloxane)을 스핀 코팅을 이용하여 실리콘 와이어 어레이 위에 증착하였다. 희석제의 함량과 스핀코팅의 회전수에 따라 폴리디메틸실록산의 박막두께를 조절하였으며, 기계적 방법으로 실리콘 와이어 어레이를 기판에서 분리할 수 있음을 보여주었다.

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와인, 그 투자 가치를 말하다

  • Yu, So-Ra
    • 주택과사람들
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    • s.193
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    • pp.34-35
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    • 2006
  • 와인에 대한 관심이 높아지면서 일부 와인 애호가들은 와인의 '맛'에 대한 관심뿐 아니라 와인의 '가치'에도 관심을 갖게 되었다. 지난 5월, 서울옥션에서 최초로 전문적인 와인 경매가 열린 것은 그 관심을 증명하는 단적인 예. 그렇다면 어떤 와인들이 투자 등급으로서 가치가 있는 것일까?

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