• 한국결정학회지
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• 제12권3호
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• pp.166-170
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• 2001

실리콘 기판에 도핑되어 있는 도판트는 종류에 따라 코발트와 실리콘 기판과의 반응에 영향을 준다. 인은 붕소나 비소에 비해 코발트와 실리콘과의 반응을 억제하여 저온 열처리 동안에 CoSi₂대신에 CoSi가 형성되도록 한다. CoSi층 내에서의 확산원소는 Si으로, CoSi 층은 Co/CoSi 계면에서 성장하며 반응에 참여하는Si 소모에 의해 생기는 기판의 빈 공간을 태우기 위해 Si 기판쪽으로 이동한다. 게이트 측벽에서는 접촉되어 있는 게이트 산화막과의 결합에 의해 CoSi층의 이동이 억제된다. 따라서 기판의 빈 공간을 태우지 못하게 되어 게이트 측벽 아래에 기공이 형성된다.

• 한국전산유체공학회지
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• 제22권1호
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• pp.1-7
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• 2017

The mixing of water and chemicals is an important process in the water purification plant. In this paper, we compare PDM(pump diffusion mixer) and hydraulic mixer at the basin in the mixing process. The proper flow rates are predicted and compared in both mixers using CFD technique. As a result, the flow rate of purifier chemical liquid should be 5% of that of water for the optimal performance of mixing process. The characteristics of the two mixing methods are compared with each other for strong and weak points on the operation of the purification system, discussed in the view point of CFD simulations.

• 한국주조공학회지
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• 제10권5호
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• pp.399-407
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• 1990

The effect of thermal cycling and isothermal exposure on the high temperature microstructural stability of unidirectionally solidified $Al-CuAl_2$ eutectic composite has been studied. A coarsening procedures of lamellar eutectic structures were initiated at growth fault region because of diffusion through low angle boundary at this region. It was considered that thermally induced residual stresses produced by thermal cycling were high enough to increase the dislocation density in Al-rich matrix phase. However, it was also considered that dislocations generated by these high thermal stresses were annihilated at high temperature by stress relaxation. Consequently, the thermal cycling up to 1440 cycles between 20 and $520^{\circ}C$ did not affect the microstructural stability.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1979년도 추계학술대회 심포지움
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• pp.245.2-246
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• 1979

Heat treated whole cell of Aspergillus niger containing glucose oxidase-catalase system was entrapped in gelatin matrix crosslinked by glutaral-dehyde. The reaction characteristics of immobilized enzyme was studied in a fludized reactor. Heat treatment enhanced the stability and improved the properties of micellium for the immobilized process. The immobilized enzyme system showed the maximum activity at $35^{\circ}C$ and at pH 5.5. The optimum substrate concentration was 0.04M glucose. The activity of immobilized glucose oxidase was in proportion to the concentration of dissolved oxygen in reaction mixture as other reaction conditions were fixed. It was also demonstrated that the limiting factor for the activity of the immobilized glucose oxidase was the oxygen diffusion resistance which increases proportionally to the glucose concentration.

• Journal of Korean Neurosurgical Society
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• 제54권2호
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• pp.139-141
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• 2013

Presented here is a 36-year-old male with arterial hypertension who developed brainstem edema and intracranial hemorrhage. Magnetic resonance scan revealed diffuse brainstem hyperintensity in T2-weighted and fluid-attenuated inversion-recovery images, with an increase in apparent diffusion coefficient values. After a reduction in blood pressure, rapid resolution of the brainstem edema was observed on follow-up. The patient's condition was thus interpreted as hypertensive brainstem encephalopathy. While many consider this a vasogenic phenomenon, induced by sudden, severe hypertension, the precise mechanism remains unclear. Prompt recognition and aggressive antihypertensive treatment in such patients are essential to prevent permanent or life-threatening neurologic injury.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 춘계 학술대회논문집
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• pp.171-176
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• 2007

A comparative study on the treatment of the turbulent heat flux with the elliptic mlending second moment closure for a natural convection is performed. Four cases of different treating the turbulent heat flux are considered. Those are the generalized gradient diffusion hypothesis (GGDH) the algebraic flux model (AFM) and the differential heat flux model (DFM). These models are implemented in the computer code specially designed for evaluation of turbulent models. Calculations are performed for a turbulent natural convection in the 1:5 rectangular cavity and the calculated results are compared with the experimental data. The results show that three models produce nearly the same accuracy of solutions.

• 대한기계학회논문집B
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• 제26권12호
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• pp.1747-1755
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• 2002

A complete theoretical treatment of the photothermal displacement technique has been performed for thermal diffusivity measurement in semi-infinite solid materials. The influence of the parameters, such as radius and modulation frequency of the heating beam and the thermal diffusivity, was studied. Usually, thermal diffusivity was determined by the deformation angle and phase angle as the relative position between the heating and probe beams. In this study, we proposed the simple analysis method based on the real part of deformation gradient as the relative position between two beams. It is independent in the parameters such as power of heating beam, absorption coefficient, reflectivity, Poisson's ratio, and thermal expansion coefficient.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.132-137
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• 2000

A complete theoretical treatment of the photothermal displacement technique has been performed for thermal diffusivity measurement in solid materials. The influence of parameters - radius and modulation frequency of pump beam and thickness of material - on the phase lag was studied. The phase decreases up to a certain position, then starts to increase and does have an asymptotic value. The position, where phase has the minimum value, is a function of thermal diffusion length thickness of sample, and radius of pump beam. A new method based on minimum phase lag is described to determine the thermal diffusivity of solid material.

• Investigative Magnetic Resonance Imaging
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• 제22권3호
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• pp.200-203
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• 2018

Metronidazole is an antimicrobial agent widely used for the treatment of anaerobic infection or antibiotics-associated diarrhea. It is generally thought to be safe, but can induce reversible toxic encephalopathy in the case of excessive or cumulative over-dose. Metronidazole-induced encephalopathy generally demonstrates the characteristic features of typical lesion location and bilaterality on magnetic resonance imaging (MRI). We report a case of metronidazole-induced encephalopathy with the involvement of asymmetric white matter. To our knowledge, only a few cases have been reported with respect to white matter lesion characteristics on MRI with diffusion-weighted images.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.120.2-120.2
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• 2017

본 연구에서는 고신뢰성 인쇄회로기판이나 플립칩 패키지에 적용되는 범프 표면처리에서 널리 사용되는, ENIG나 ENEPIG 대체를 위한 electroless Pd/immersion Au(EPIG)에 대하여 연구하였다. Transmission electron microscopy(TEM) 분석 결과 형성된 Au layer는 crystalline, Pd layer는 amorphous 임을 확인하였으며, 열처리 후 X-Ray photoelectron spectroscopy(XPS)를 통하여 EPIG층이 하부 copper의 확산방지막으로서 효과가 있음을 알 수 있었다. 또한, 비정질 Pd layer가 확산을 방지하기 위하여는 일정수준 이상의 두께가 필요하며, 그 두께는 35~65nm 수준임을 알 수 있었다.