• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1996년도 추계학술발표회논문집(2)
• /
• pp.571-576
• /
• 1996

The 3-stage cascade composed of the multisection-type bithermal $H_2$/$H_2O$-exchange columns was suggested for heavy water separation. In order to study the separation characteristics for the cascade, a matrix equation with 18 simultaneous equations was composed and the concentrations and flow rates were calculated for the all parts of the cascade. Product D-concentration decreases and extraction yield increases with increasing cut in each stage, which is one of the principal parameters of the separation characteristics. The optimization of the 3-stage cascade can be made by case study using the matrix equation.

• Geomechanics and Engineering
• /
• 제5권3호
• /
• pp.223-240
• /
• 2013

In the present study an attempt was made to predict the complex nonlinear parameters of the soil-pile system subjected to the vertical vibration of rotating machines. A three dimensional (3D) finite element (FE) model was developed to predict the nonlinear dynamic response of full-scale pile foundation in a layered soil medium using ABAQUS/CAE. The frequency amplitude responses for different eccentric moments obtained from the FE analysis were compared with the vertical vibration test results of the full-scale single pile. It was found that the predicted resonant frequency and amplitude of pile obtained from 3D FE analysis were within a reasonable range of the vertical vibration test results. The variation of the soil-pile separation lengths were determined using FE analysis for different eccentric moments. The Novak's continuum approach was also used to predict the nonlinear behaviour of soil-pile system. The continuum approach was found to be useful for the prediction of the nonlinear frequency-amplitude response of full-scale pile after introducing the proper boundary zone parameters and soil-pile separation lengths.

• 한국항공우주학회지
• /
• 제37권12호
• /
• pp.1252-1257
• /
• 2009

항공기의 외부장착물 분리해석이 가능한 Off-line 6-DOF 시뮬레이션 프로그램을 개발 하였다. 개발한 프로그램은 풍동시험이나 CFD 해석을 통해 구축된 공력 데이터베이스를 이용하여 외부장착물의 분리 궤적을 예측할 수 있다. 공력 계수의 계산에는 flow angle 방법을 적용하였으며 분리 궤적 계산에는 사출력과 구속 조건의 적용이 가능하도록 하였다. 개발한 프로그램을 이용하여 군용항공기의 분리 궤적을 계산하였으며 이를 CTS 시험 결과와 비교하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
• /
• pp.276-276
• /
• 2013

Here we report an integrated microdevice consisting of an efficient passive mixer, a magnetic separation chamber, and a capillary electrophoretic microchannel in which DNA barcode assay, target pathogen separation, and barcode DNA capillary electrophoretic analysis were performed sequentially within 30 min for multiplex pathogen detection at the single-cell level. The intestine-shaped serpentine 3D micromixer provides a high mixing rate to generate magnetic particle-pathogenic bacteria-DNA barcode labelled AuNP complexes quantitatively. After magnetic separation and purification of those complexes, the barcode DNA strands were released and analyzed by the microfluidic capillary electrophoresis within 5 min. The size of the barcode DNA strand was controlled depending on the target bacteria (Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella typhimurium), and the different elution time of the barcode DNA peak in the electropherogram allows us to recognize the target pathogen with ease in the monoplex as well as in the multiplex analysis. In addition, the quantity of the DNA barcode strand (~104) per AuNP is enough to be observed in the laser-induced confocal fluorescence detector, thereby making single-cell analysis possible. This novel integrated microdevice enables us to perform rapid, sensitive, and multiplex pathogen detection with sample-in-answer-out capability to be applied for biosafety testing, environmental screening, and clinical trials.

• International Journal of Aerospace System Engineering
• /
• 제11권1호
• /
• pp.1-3
• /
• 2024

Around the world, fossil fuel energy is being replaced with renewable energy due to environmental problems and sharp price increases. Many countries are making a change in the direction of moving toward eco-friendliness by reducing carbon emissions. Among renewable energies, the wind energy is eco-friendly because it produces electricity by wind power without carbon emissions, and it attracts attention worldwide as a great alternative to the exhausted fuel energy. To improve the efficiency of wind turbines, large and extra-large wind turbines have been developed all over the world by increasing install and diameter. These wind turbines have difficulty in transport after manufacture because of their size and height. Since the height of wind turbine blades is higher than the existing tunnel height, it is impossible to transport them. In this study, therefore, a 5 MW class large blade was separated for transport easiness as wind power generators became larger globally. Aerodynamic design and analysis was carried out for the blade. After performing structural design and analysis with the model designed, the stress concentration of the analyzed model and the various factors for consideration when separating were considered to conduct the study of selecting the optimal blade separation positions.

• 멤브레인
• /
• 제16권3호
• /
• pp.204-212
• /
• 2006

이산화탄소에 대한 가소화 안정성 및 이산화탄소/질소의 분리특성이 탁월한 폴리이서술폰(PES)중공사 분리막에 의한 이산화탄소 분리특성을 수치해석으로 알아보고자 하였다. 공정변수에 따른 이산화탄소 분리 거동을 예측하기 위하여 공급 기체와 투과기체가 같은 방향으로 흐르는 병류 흐름에 대한 분리막 공정 지배 방정식을 5차 Runge-Kutta-Verner 방법을 사용하여 Compaq Visual Fortran 6.6 소프트웨어를 이용 공정모사 프로그램을 개발하였다. 개발된 프로그램을 사용하여 수치해석을 수행한 결과, 이산화탄소 투과특성에 영향을 주는 가장 중요한 인자로서 공급 이산화탄소 분압, 투과측과 분리막 내부의 압력비 그리고 공급 기체가 분리막 내부에 머무르는 체류 시간임을 알 수 있었다.

• International Journal of Fluid Machinery and Systems
• /
• 제2권2호
• /
• pp.110-120
• /
• 2009

Generally the fluid flows within the centrifugal impeller passage as a decelerating flow with an adverse pressure gradient along the stream wise path. This flow tends to be in a state of instability with flow separation zones on the suction surface and on the front shroud. Hence several experimental attempts were earlier made to assess the efficacy of using boundary layer fences to trip the flow in the regions of separation and to make the flow align itself into stream wise direction so that the losses could be minimized and overall efficiency of the diffusion process in the fan could be increased. With the development of CFD, an extensive numerical whole field analysis of the effect of boundary layer fences in discrete regions of suspected separation points is possible. But it is found from the literature that there have been no significant attempts to use this tool to explore numerically the utility of the fences on the flow field. This paper attempts to explore the effect of boundary layer fences corresponding to various geometrical configurations on the impeller as well as on the diffuser. It is shown from the analysis that the fences located on the impellers near the trailing edge on pressure side and suction side improves the static pressure recovery across the fan. Fences provided at the radial mid-span on the pressure side of the diffuser vane and near the leading edge and trailing edge of the suction side of diffuser vanes also improve the static pressure recovery across the fan.

• 한국항공우주학회지
• /
• 제32권5호
• /
• pp.24-29
• /
• 2004

본 논문에서는 저속통제기로부터 비상 시 분리되는 외부연료탱크 및 LAU-131 로켓발사기의 분리안전성을 보이기 위하여 수행한 자유낙하 풍동시험, MSAP을 이용한 해석과 비행 시험의 연구결과를 종합하였다. 자유낙하형의 bomb rack을 사용하는 비행시험 중의 분리안 전성의 확인과 MSAP의 보정용 자료 생성을 위하여 수행한 아음속풍동을 이용한 자유낙하 시험의 결과에 대하여 기술하였다. 보정된 MSAP으로 자유낙하형과 사출형의 bomb rack 을 사용하였을 때의 분리안전성 해석을 수행하였다. MSAP 해석 결과를 이용한 상관관계 해석을 통하여 자유낙하형의 bomb rack을 사용할 경우의 투하 안전성도 보였다. 또한, 실기 비행시험을 통하여 투하시험을 수행하였으며 이를 해석결과와 비교하였다. 마지막으로, 풍동 시험, 해석결과 및 비행시험의 결과를 종합하여 저속통제기의 안전투하영역을 확정하였다.

• 항공우주시스템공학회지
• /
• 제16권6호
• /
• pp.123-128
• /
• 2022

본 연구는 전개형 SAR 안테나에 적용하기 위한 비폭발 분리장치를 제안하였다. Ni-Cr 와이어를 감아 제작된 분리장치를 이용하여 SAR 안테나의 벨트가 전개되지 않도록 구속한다. 분리 장치를 구속하는 Ni-Cr 와이어는 발열을 통해 절단함으로써 벨트 전개 시 충격량을 최소화한다. 분리장치의 설계를 위해 설계하중(99g)과 preload를 고려하여 AL과 Ti을 대상으로 유한요소 해석을 수행하였다. AL을 이용 시 해석결과, 최대 변형량이 0.256 mm 발생하였고, 안전마진은 +0.09로 확인되었다. 또한 궤도상 열분석을 수행하여 온도분포를 확인한 결과, 최저온 궤도와 최고온 궤도에서 -50~+2℃의 온도분포와 -10~+90℃의 온도분포를 각각 나타내어 우주환경에서도 구속분리장치가 안정적임을 입증하였다.

• 아동학회지
• /
• 제27권2호
• /
• pp.101-126
• /
• 2006

In this comparison of the relative effects of children's separation from their parents, socio-emotional adjustment was assessed by emotional and behavioral problems and emotional intelligence. Subjects were 502 elementary school children separated from their parents(162 in Yanbian and 340 in Korea) and their caregivers. Data analysis was by frequency, t-test, and multiple regression controlled by gender and grade in school. Caregivers living with children and their parenting efficacy were significant variables for the development of socio-emotional adjustment in Korean-Chinese children in Yanbian, but reasons for parent-child separation, caregivers' psychological and behavioral characteristics, and SES were significant variables for children in Korea. Implications are that regional differences should be considered in understanding and supporting the development of children's socio-emotional adjustment.