• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.85-88
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• 2001

Since mountainous area has access restrictions for field work, assessors need to establish a conceptual model of the contamination prior to the field investigation. In this study we established a conceptual model of the contamination based on site inspection and geological survey, followed by the field investigation for the petroleum spill site. In the conceptual model, we estimated that tile contamination should have spread by groundwater and topographical characteristics within the top soil layer. The spread of contamination through rock was not considered in the conceptual model due to impermeable characteristics of metasyenite. The contaminated environmental media of the petroleum spill site include soil and groundwater. According to the analysis result of the contamination, the volume of contaminated soil is estimated approximately 4, 150 cubic meters (7, 055 ton) with most contaminants existing along the groundwater flow within top soil layer.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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• pp.25-28
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• 2003

베어링/실 시험설비 (BST)는 다양한 매체 (물, 액체질소, 액체산소)에서 액체로켓 엔진의 터보펌프를 위한 베어링과 실을 시험하기 위한 장비이다. 베어링 성능특성 시험은 베어링을 통과하는 냉각 유량과 축 방향 및 반경방향의 하중을 모사하여 시험이 수행된다. 실 시험의 목적은 실을 통과하는 누수량과 시간에 따른 누수량의 변화를 결정하기 위함이다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1997년도 총회 및 춘계 학술발표회 논문집
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• pp.79-82
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• 1997

토양내에서 오염유기물질이 불포화토양내에 유입될 때의 dispersion coefficient를 adsorption과 desorption과정에 대해 알아보았다. apparent dispersion coefficient를 측정하기 위해 일상적인 상대습도(46%)조건에서 parametric analysis를 행하였다. 실험에 사용된 토양은 fine sand와 silt-clay혼합시료였고, 흐름방향은 상향과 하향으로 하였다. 그리고, Freon gas를adsorbing solute로 사용하였다. 오염물질로는 DCM, TCE, DCB를 사용하였다. 분석을 위해서 linear와 probability scale의 breakthrough curve를 사용하였다. 공기에서의 diffusion coefficient의 예측을 위하여 Graham's law를 계산에 사용하였고, DCM diffusion coefficient는 0.098$\textrm{cm}^2$/s로 계산되었다. 연구결과, adsorption과 desorption의 속도는 차이가 있는 것으로 나타났으며, diffusion이 flow regime을 좌우하는 것으로 나타났다. 그리고, desorption에서의 D$^{a}$ D$^{o}$ 는 1보다 클수도 있다. 또한, dispersion은 silt-clay혼합시료에서의 속도와 함께 증가한다. dispersion은 Freon의 sorption방향에 크게 의존한다.

• Carbon letters
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• 제25권
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• pp.25-32
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• 2018

In this study, a thermal-gradient chemical vapor infiltration (TG-CVI) process was numerically studied in order to enhance the deposition uniformity within the preform. The computational fluid dynamics technique was used to solve the governing equations for heat transfer and gas flow during the TG-CVI process for two- and three-dimensional (2-D and 3-D) models. The temperature profiles in the 2-D and 3-D models showed good agreement with each other and with the experimental results. The densification process was investigated in a 2-D axisymmetric model. Computation results showed the distribution of the SiC deposition rate within the preform. The results also showed that using two-zone heater gave better deposition uniformity.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.630-631
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• 2000

지방산과 당의 transesterification에 의하여 제조되는 당에스테르를 분리정제하는 방법으로 크로마토그라피방법을 조사하였다. 당에스테르제조에 사용되고 있는 각종 지방산(oleic, stearic, palmitic acid)과 당에스테르의 크로마토그라피 용출특성을 이동상의 유속과 온도, 그리고 주입량을 변화시켜 관찰하였다. 본 실험에서 사용한 column은 Silica 계통의$C_{18}$ column($3.9{\times}300mm$) 이었으며 본 실험에서 조사한 지방산과 당에스테르의 혼합물은 모두 높은 해상도로 분리되는 것을 관찰하였다.

• 한국전기전자재료학회논문지
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• 제17권8호
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• pp.812-822
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• 2004

This paper shows that carbon nanotubes can be applied to a nanopipette. Nano space in atomic force microscope multi-wall carbon nanotube tips is filled with molecules and atoms with charges and then, the tips can be applied to nanopipette when the encapsulated media flow off under applying electrostatic forces. Since the nano space inside the tips can be refilled, the tips can be permanently used in ideal conditions of no chemical reaction and no mechanical deformation. Molecular dynamics simulations for nanopipette applications demonstrated the possibility of nano-lithography or single-metallofullerene-transistor array fabrication.

• 한국해양공학회지
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• 제20권6호
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• pp.35-40
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• 2006

In recent years, there's been strong demand for seawalls that havea gentle slope and permeability that serveswater affinity and disaster prevention from wave attack. The aim of this study is to examine wave transformation, including wave run-up that propagates on the coastal structures. A numerical model based on the weak nonlinear dispersive Boussinesq equation, together with the unsteady nonlinear Darcy law for fluid motion in permeable layer, is developed. The applicability of this numerical model is examined through Deguchi and Moriwaki's hydraulic model test on the permeable slopes. From this study, it is found that the proposed numerical model can predict wave transformation and run-up on the gentle slope with a permeable layer, but can't show accurate results for slopes steeper than about 1:10.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1429-1434
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• 2003

A number of dust particles are intruded into ODD(Optical disk drive) due to the flow caused by disk rotation and are adhered to a lens or disk surface. The space between the disk and the lens is being reduced. Someone indicates the problems of this drive that are relatively small data storing capacity and slow access time. In recent, the problems of this optical disk drive mentioned above are being solved by adding the speed of the disk's revolution, making the actuator high-speed or light, and making the beam spot size smaller than making the space narrow between disk and lens. These particle contamination affects seriously RF Signal, readout signal in an ODD. Especially, the affected parts by a particle contamination in an ODD's readout signal are objective lens and media.

• Journal of Chest Surgery
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• 제6권1호
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• pp.51-56
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• 1973

This is one case report of successful resection of the aneurysm of the thoracic aorta, which det-ected by thoractomy unexpectedly, in the Department of Thoracic Surgery, Hanyang University Hospital. The patient was a 34 years old woman and subjective complaints was not related with the aneurysm. Chest film showed a small round hazy shadow in the left margin of the upper posterior mediastinum. A saccular aneurysm located on the descending thoracic aorta, 7cm distal to the left subclavian artery and arouse from the antero-lateral wall of the aorta. Excision of the saccular aneurysm was performed by cross clamping the descending aorta above and below the aneurysm, and then the defect of the aortic wall was closed by aortorrhaphy with continuous suture. Crossclamping time was required 15 minute. Histopathologically, the wall of the aneurysm consisted of all layers of the arterial wall, that is, intima, media and adventitia. Postoperative course was uneventful and aortogram showed good continuity of the blood flow of the entire aorta.

• Advances in biomechanics and applications
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• 제1권4호
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• pp.227-237
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• 2014

The in vitro construction of osteo-articular large implants combining biomaterials and cells is of great interest since these tissues have limited regeneration capability. But the development of such organoids is particularly challenging, especially in the later time of the culture, when the extracellular matrix has almost filled the initial porous network. The fluid flow needed to efficiently perfuse the sample can then not be achieved using only the hydraulic driving force. In this paper, we investigate the interest of using an electric field to promote mass transport through the scaffold at the late stage of the culture. Based on the resolution of the electrokinetics equations, this study provides an estimation of the necessary electric driving force to reach a sufficient oxygen perfusion through the sample, thus analyzing the feasibility of this concept. The possible consequences of such electric fields on cellular activities are then discussed.