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전자기력에 의한 연주 Slab 내의 교반유동에 관한 수치적 연구
이재헌,이성우,신영길,김희창 대한금속재료학회(대한금속학회) 1990 대한금속·재료학회지 Vol.28 No.1
A Numerical study was performed for the two-dimensional turbulent stirring flow created by linear motor in a continuous casting system. A k-εturbulent model was applied to solve time-averaged turbulent momentum equations within the computation domain. Four different situations in a stirring system being consisted of two-dimensional slab of 1 m(width) × 0.2 m(height) have been investigated, that is : Model (A) : W =0.1 m and B_0=0.01 tesla, Model (B) : W =0.3 m and B_0=0.01 tesla, Model (C) : W =0.1 m and B_0=0.02 tesla, Model (D) : W =0.3 m and B_0=0.02 tesla, where W is the length of linear motor and B_0 is the magnetic flux applied on the motor-side-surface of the slab. The results shows that the flow characteristics depends mainly on the magnetude of B_0 not on W. The order of the magnitudes of turbulent intensity at four flow situations were almost same. However, the magnitude of turbulent viscosity became much less in case of greater B_0 than in smaller B_0. Therefore it is recommended that the stirrer with greater B_0 should be used to make finer stirring action.
Lee, Yu Yong,Park, Young Joon,Cho, B. W.,Lee, Jae-Bong 한국부식방식학회 2002 Corrosion Science and Technology Vol.31 No.1
Effects of three different types of current waveforms and current densities on damascene copper line filling capability were investigated. The electroplating solution developed for printed circuit board (PCB) was used for Damascene plating. Three different types of current wave forms i.e. direct current (DC), Pulsed current, and periodic (PR) current methods were chosen for electroplating with the variation of current densities. The cross-section profiles of deposited wafers were analyzed by Field Emission Scanning Electron Microscope (FE-SEM). Trenches were successfully superfilled without void for Cu lines with 0.4 and 0.8m width according to each current waveform. Each current waveform was optimized with the proper current density values. The critical causes for the center and the sidewall void formations were investigated. Copper plating profiles due to DC current waveform showed center void in the final stage of plating because the copper deposition on the trench top comer was faster than those inside of trench. Oh the contrary, Pulsed or PR current methods tend to result in center voids due to the faster deposition on the sidewall. Sidewall void formation could be attributed to the localized corrosion of copper seed layers due to long immersion of the wafer in the electrolyte at zero current state before plating.
( Jae Min Shin ),( Tae Hoon Lee ),( Sang Heum Park ),( Sang Goo Kang ),( Yeon Seon Lee ),( Suk Ja Park ),( Mi Gyeong Ku ),( Suck Ho Lee ),( Il Kwun Chung ),( Hyun Jong Choi ),( Jong Ho Moon ),( Sang W 대한소화기학회 2013 Gut and Liver Vol.7 No.1
Background/Aims: During endoscopic retrograde cholangiopancreatography (ERCP), all efforts should be made to be aware of radiation hazards and to reduce radiation exposure. The aim of this study was to investigate the status of radiation protective equipment and the awareness of radiation exposure in health care providers performing ERCP in Korean hospitals. Methods: A survey with a total of 42 questions was sent to each respondent via mail or e-mail between October 2010 and March 2011. The survey targeted nurses and radiation technicians who participated in ERCP in secondary or tertiary referral centers. Results: A total of 78 providers from 38 hospitals responded to the surveys (response rate, 52%). The preparation and actual utilization rates of protective equipment were 55.3% and 61.9% for lead shields, 100% and 98.7% for lead aprons, 47.4% and 37.8% for lead glasses, 97.4% and 94.7% for thyroid shields, and 57.7% and 68.9% for radiation dosimeters, respectively. The common reason for not wearing protective equipment was that the equipment was bothersome, according to 45.7% of the respondents. Conclusions: More protective equipment, such as lead shields and lead glasses, should be provided to health care providers involved in ERCP. In particular, the actual utilization rate for lead glasses was very low. (Gut Liver 2013;7:100-105)
[미발표] 철도 적용을 위한 아스팔트 바인더 특성 및 배합설계 기준 검토
나일호(Il-Ho Na),양재봉(Jae B. Yang),이성혁(Seong H. Lee),이진욱(Jin W. Lee),김광우(Kwang W. Kim) 한국철도학회 2012 한국철도학회 학술발표대회논문집 Vol.2012 No.10
아스팔트 콘크리트를 철도 분야에서 소음 및 진동저감 등의 목적으로 인해 적용한 선진국 사례들이 늘어나고 관련 연구들이 활발하게 진행 되고 있다. 이에 최근 국내에서도 아스팔트 콘크리트를 이용한 기술적 검토가 진행 중이다. 아스팔트 콘크리트의 철도적용을 위해서는 국내에서 생산되고 있는 바인더와 혼합물의 검토가 선행되어야 하고 철도 적용에 적합한 배합설계가 검토 되어야 한다. 따라서 본 연구에서는 국내에서 생산되고 있는 바인더 및 혼합물의 Stiffness 를 검토하고, 국외에서 제시한 철도적용 아스팔트 콘크리트 배합설계 기준과 비교하고자 하였다. Since the asphalt concrete (AC) base course under the railway is known to be useful for noise reduction and vibration attenuation, application of AC base is increasing in many advanced countries, in which many related studies are actively conducted and published. Currently, technical reviews for using asphalt concrete for railway are under progress in a few domestic research institutes. Review of binders and mixtures, which are manufactured in domestic markets, must be preceded for AC applications to railway. The suitability of various binders should be carefully investigated for railway applications. Therefore, this study was initiated to review stiffness of aforementioned material (binders & mixtures) and compare current domestic mix design with railway applications for mix design presented in overseas.
정대원(Dae-Won Chung),고재하(Jae-Ha Ko),윤근영(Keun-Young Yoon) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.5
최근 인공지능 딥러닝(AI Deep Learning, DL) 기법은 공학 분야의 모델예측과 진단방법으로, 그 정확성이 검증되고 인증되면서 다양한 분야에서 그 우수한 성능을 발휘하고 널리 활용되고 있다. 본 논문에서는 이런 점에 착안하여 전력수요의 최적 관리를 위해 단기전력 수요예측 모델에 적용하는 방안을 제안한다. 단기간 전력수요 예측은 전력수요관리 측면에서 중요하나 그 정확성이 낮아서, 보다 우수한 성능 기법이 요구되었던 점에 비추어 적용성이 매우 높고, 기존의 방식에 비해 보다 우수한 성능과 정확한 전력수요관리가 가능하다. 특히 특정지역의 수용가의 사용된 전력량의 데이터를 바탕으로 전력수요 예측을 적용하였다. 또한 전력수요의 평균절대백분비오차(MAPE)를 비교하여, 전력수요 예측 결과의 정확성과 타당성을 검증하였다. 이를 통해 전력수요 변동에 따른 단주기 전력수요 예측 모델의 구현성 및 향후 활용 가능성을 확인하였다.