• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.32-42
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• 2004

Recently, plasma surface-cleaning or surface-etching techniques have been focused in respect of the decontamination of spent or used nuclear parts and equipment. In this study the removal rate of metallic cobalt surface is experimentally investigated via its surface etching rate with a $CF_4-o_2$mixed gas plasma. Experimental results reveal that a mixed etchant gas with about 80% $CF_4$-20% $O_2$ (molar) gives the highest reaction rate and the rate reaches 0.06 ${\mu}m$/min at $380^{\circ}C$ and ion-assisted etching dramatically enhances the surface reaction rate. With a negative 300 V DC bias voltage applied to the substrate, the surface reaction initiation temperature lowers and the rate increases about 20 times at $350^{\circ}C$ and up to 0.43 ${\mu}m$/min at $380^{\circ}C$, respectively. Surface morphology analysis confirms the etching rate measurements. Auger spectrum analysis clearly shows the adsorption of fluorine atoms on the reacted surface. From the current experimental findings and the results discussed in previous studies, mechanistic understanding of the surface reaction, fluorination and/or fluoro-carbonylation reaction, is provided.

• Journal of Chest Surgery
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• 제20권4호
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• pp.730-744
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• 1987

From Nov. 1980 to Jun. 1987, 270 primary lung cancer patients were operated on at the department of Thoracic & Cardiovascular Surgery, Seoul National University Hospital. There Were 223 males & 47 females with 55.5 years of mean age. There were 151 [55.9%] squamous cell ca., 43 [18.8%] adenoca., 8 [3.5%] undiff. large cell, 9 [3.9%] undiff. small cell ca. & 18 [7.9%] mixed type, and also composed of 65 [28.3%] stage I, 31 [13.5%] stage II and 133 [58.1%] of stage III cases. They received 78 [34.1%] lobectomies, 62 [27.1%] pneumonectomies and 60 [26.2%] exploratory thoracotomies with 70% resectability rate. The five year actuarial survival rate of all patients was 37%. According to TNM stage, five year survival rate of the patients in stage I was 71%, those of stage II was 29% and of stage III 21%. According to histological cell type, five year actuarial survival rate of the squamous cell ca. was 35%, of adenoca. 49%, of undiff. large cell. 22%, 2 year survival rate of undiff. small cell was 31% and 3 year survival rate of mixed type was 47%. Hospital death was 2 case with a 1.3% early postop. mortality rate.

• 한국전기전자재료학회논문지
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• 제11권2호
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• pp.101-105
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• 1998

This paper describes anisotropic etching technology of highly doped polysilicon. The main etching gases are $Cl_2$ and $SiCl_4$ for reactive ion etching of polysilicon. The mixed $CHCl_3$ to main etching gas makes polymer on etching side wall, so it prevents side etching of polysilicon. The etch rate of polysilicon is increased with increasing RF power. But the etching rate is decreased as the flow rate of $CHCl_3$ is increased with fixed RF power. The etch selectivity of polysilicon and $SiO_2$ is about 12:1. And that of polysilicon and $Si_3N_4$ is about 19:1. In the main etching gas condition, the slope of polysilicon is same as that of photoresist. But in the mixed $CHCl_3$ condition, the slope of polysilicon is larger than that of photoresist. This represents that the polymer made on side wall by added $CHCl_3$ prevents side etching, so anisotropic etching can be possible by polymer.

• Journal of Magnetics
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• 제18권3호
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• pp.321-325
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• 2013

The problem of mixed convection in a differentially heated lid-driven square cavity filled with Cu-water nanofluid under effect of a magnetic field is investigated numerically. The left and right walls of the cavity are kept at temperatures of $T_h$ and $T_c$ respectively while the horizontal walls are adiabatic. The top wall of the cavity moves in own plane from left to right. The effects of some pertinent parameters such as Richardson number (ranging from 0.1 to 10), the volume fraction of the nanoparticles (ranging 0 to 0.1) and the Hartmann number (ranging from 0 to 60) on the fluid flow and temperature fields and the rate of heat transfer in the cavity are investigated. It must be noted that in all calculations the Prandtl number of water as the pure fluid is kept at 6.8, while the Grashof number is considered fixed at 104. The obtained results show that the rate of heat transfer increases with an increase of the Reynolds number, while but it decreases with increase in the Hartmann number. Moreover it is found that based the Richardson and Hartmann numbers by increase in volume fraction of the nanoparticles the rate of heat transfer can be enhanced or deteriorated compared to the based fluid.

• 한국수자원학회논문집
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• 제48권1호
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• pp.23-35
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• 2015

본 연구에서는 3차원 수치모형을 이용하여 염수 대수층 내 담수 주입량에 따른 주입정과 양수정 사이의 담수체의 거동을 수치적으로 분석하였다. 대수층 내에 8개의 주입정이 동심원 상에 등간격으로 배열되어 있으며, 동심원 중심에 한 개의 양수정이 위치해 있다. 주입량이 상대적으로 작은 경우 주입정 주변의 담수체는 인근의 주입정에서의 담수체와 서로 혼합되지 않고 독립적으로 분포한다. 그러나 주입량이 증가함에 따라 담수체의 크기는 점차적으로 증가하며, 주입정과 주입정 사이에 염수와 담수가 혼합되어 있는 영역이 나타난다. 혼합되는 정도는 주입량이 증가함에 따라 증가되며, 이러한 현상은 양수정 주변에서도 동일하게 나타난다. 또한주입량이 증가할수록 양수정 주변 및 내에서의 염수비율이 점차적으로 감소하는 경향을 나타내었다.

• 방사성폐기물학회지
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• 제18권3호
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• pp.355-362
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• 2020

The corrosion behavior of the Inconel X-750 alloy was investigated for its potential application under a Cl₂-O₂ mixed gas flow in an Ar atmosphere. The corrosion rate was found to be negligible at temperatures up to 400℃ under a flow rate of 30 mL·min^-1 Cl₂ + 170 mL·min^-1 Ar, whereas an exponential increase was observed in the corrosion rate at temperatures greater than 500℃. The suppression of the corrosion reaction due to the presence of O₂ was verified experimentally at flow rates of 30 mL·min^-1 Cl₂ (4.96 g·m^-2·h^-1), 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂ (2.02 g·m^-2 ·h^-1), and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂ (1.34 g·m^-2·h^-1) under a constant Ar flow rate of 170 mL·min^-1 at 600℃ for 8 h. The surface morphology analysis results revealed that porous surfaces with tunnel-type holes were produced under the Cl₂-O₂ mixed-gas condition. Furthermore, the effects of the Cl₂ flow rate on the corrosion rate were investigated, indicating that its impact was negligible within the range of 5-30 mL·min^-1 Cl₂ at 600℃.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.71-72
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• 2022

In this paper, the performance evaluation of the vibration damping ratio according to the polymer mixing ratio of the polymer modified mortar used as the floor finishing material of the apartment building structure was evaluated. To compare the vibration damping rate, ordinary potland cement (OPC) mortar and polymer modified mortar (PMM) were prepared. In addition, the mixed polymer was mixed with Styrene Butadiene Rubber (SBR) liquid polymer with a solid content of about 49%. Accordingly, the W/C of the test specimen was adjusted and compounded, and the experiment was conducted by mixing 5 types of the test specimen: OPC-60, PMM-5%, PMM-10%, PMM-15%, and PMM-20%. In addition, in order to adjust the W/C of the specimen, the fluidity of each specimen was set as 210 (±5) mm. The specimens measured density and flow in fresh mortar and after curing for 28 days, flexural strength, compressive strength and ultrasonic pulse were measured. The attenuation rate was shown. The experimental results showed that the density increased according to the mixing of the polymer, the flexural strength increased as the mixing rate of the polymer increased, and the compressive strength was decreased. In addition, it was shown that the vibration damping rate increases with the increase in the amount of polymer incorporated.

• 방송공학회논문지
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• 제18권4호
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• pp.535-542
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• 2013

본 논문에서는 고속 및 고인식률의 성능을 갖는 영상인식 엔진 구조를 제안한다. 본 엔진은 2단계의 특징점 추출 및 분류 알고리즘을 수행하여 자동차와 보행자를 인식할 수 있다. 엔진의 인식률을 높이기 위해 HOG 특징점 값과 LBP 특징점 값을 같이 사용하여 알고리즘을 구성하였으며, 처리 속도를 높이기 위해 병렬 구조를 개선하여 하드웨어를 설계하였다. 실험결과를 통해 설계한 엔진이 초당 90프레임의 인식 처리가 가능하며 FPPW $10^{-4}$ 하에서 97.7%의 보행자 인식률을 가짐을 보인다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.286-291
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• 2001

Most cracks in the structure occur under mixed mode loadings and those propagation depend on the stress ratio very much. So, it is necessary to study the fatigue behavior under mixed mode loading as stress ratio changes. In this paper, fatigue crack propagation behavior was investigated respectively at stress ratio 0.1, 0.3, 0.5, 0.7 and we change loading application angle to $0^{\circ},\;30^{\circ},\;60^{\circ}$ to apply various loading. mode. The mode I and II stress intensity factors of CTS specimen used in this study were calculated by displacement extrapolation method using FEM(ABAQUS). Using both the study through the experiment and the theoretical study through FEM analysis, we studied the relation between crack propagation rate and stress intensity factor range at each loading mode due to the variation of stress ratio. Also, when the crack propagated under given stress condition and given loading mode condition, we studied what the dominant factors of the crack propagation rate were at each case.

• 복식문화연구
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• 제13권2호
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• pp.289-299
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• 2005

Through the formative analysis of the traditional jokakbo, we have composed surface composition that was made by a perfect square, triangle, a weather vane type, vertical type, cintamani type, and a mixed rectangular. And we have composed 18 kinds of motif stimulants that was made by vivid tone, pale tone, and so on, and finally analyzed sensibility image, preference rate of them. The cause of composition for the sensibility image of stimulant was composed by the cause of simplicity characteristics, interesting characteristics, rigid-flexibility characteristics, and modern characteristics. And from these things, the cause of simplicity characteristics and the cause of interesting characteristics were revealed as important dimensional factors of sensibility image. The sensibility image of motif was revealed as a simple image of perfect square, a feminine image of cintamani type, a modern image of mixed rectangular. And black-white colored mixed rectangular and chromatic colored cintamani type were also revealed as an interesting image. The preference rate of motif is related with the cause of interesting characteristics and simplicity characteristics, it also has been revealed to prefer the pale tone than others. And it also has been revealed that achromatic colored mixed rectangular, cintamani type of vivid tone, perfect square and rectangular of pale tone were mostly preferred.