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폴리카보실란으로부터 제조된 탄화규소 중공사의 미세구조제어
신동근,공은배,조광연,권우택,김영희,김수룡,홍준성,류도형,Shin, Dong-Geun,Kong, Eun-Bae,Cho, Kwang-Youn,Kwon, Woo-Tek,Kim, Younghee,Kim, Soo-Ryong,Hong, Jun-Sung,Riu, Doh-Hyung 한국세라믹학회 2013 한국세라믹학회지 Vol.50 No.4
SiC hollow fiber was fabricated by curing, dissolution and sintering of Al-PCS fiber, which was melt spun the polyaluminocarbosilane. Al-PCS fiber was thermally oxidized and dissolved in toluene to remove the unoxidized area, the core of the cured fiber. The wall thickness ($t_{wall}$) of Al-PCS fiber was monotonically increased with an increasing oxidation curing time. The Al-PCS hollow fiber was heat-treated at the temperature between 1200 and $2000^{\circ}C$ to make a SiC hollow fibers having porous structure on the fiber wall. The pore size of the fiber wall was increased with the sintering temperature due to the decomposition of the amorphous $SiC_xO_y$ matrix and the growth of ${\beta}$-SiC in the matrix. At $1400^{\circ}C$, a nano porous wall with a high specific surface area was obtained. However, nano pores grew with the grain growth after the thermal decomposition of the amorphous matrix. This type of SiC hollow fibers are expected to be used as a substrate for a gas separation membrane.
분자량이 조절된 폴리카보실란으로부터 제조한 SiC Fiber의 특성분석
신동근,류도형,김영희,김형래,박홍식,김현이,Shin, Dong-Geun,Riu, Doh-Hyung,Kim, Younghee,Kim, Hyung-Rae,Park, Hong-Sik,Kim, Hyoun-Ee 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.8
Polycarbosilane was synthesized by the Kumada rearrangement of polydimethylsilane in the presence of zeolite (ZSM-5) as a catalyst at $350^{\circ}C$. The prepared polycarbosilane had very low molecular weight ($M_w=500$), so that it was not suitable to fabricate SiC fiber by melt spinning. Further polymerization of PCS was conducted around $400^{\circ}C$ to obtain spinnable polycarbosilane. After polymerization, the polycarbosilanes were isolated by distillation according to the molecular weight distributions. The PCS with a controlled molecular weight distribution was spun into continuous polycarbosilane green fibers. The PCS green fiber was successfully transformed into silicon oxycarbide fiber. The room temperature strength of the SiC fiber was around 1.5 - 1.8 GPa. The oxidation behavior and the tensile strength after oxidation were also evaluated.
신동근,윤기용,이승현,이규세,강영종,Shin,Dong-Geun,Yoon,Ki-Yong,Lee,Seung-Hyun,Yi,Gyu-Sei,Kang,Young-Jong 한국방재학회 2007 한국방재학회논문집 Vol.7 No.5
본 연구에서는 전주의 공칭강도를 계산하기 위해 이론적 방법에 의해 P-M상관도 프로그램을 개발하였다. 그리고 이를 바탕으로 기존 연구와 검증하고 전주의 공칭강도<TEX>$(M_n)$</TEX>를 산정하였다. 설계기준에 제시된 파괴강도<TEX>$(M_r)$</TEX>와 본 연구에서 산정한 전주의 공칭강도<TEX>$(M_n)$</TEX>를 비교 분석한 결과 현재 사용하고 있는 전주의 공칭강도가 설계기준<TEX>$(M_r)$</TEX>보다 작게 산정되었다. 따라서 공칭강도 증대를 위해 인장근/보강근의 지름 증가, 보강근의 개수 증가, 인장근의 위치변화, 전주의 두께 변화 등의 매개변수를 선정하여 선정된 매개변수를 고려한 전주의 공칭강도<TEX>$(M_n)$</TEX>를 설계기준의 공칭강도<TEX>$(M_n)$</TEX>와 비교 분석하였다. In this study, a program based on the P-M interaction curve is developed to calculate the nominal strength of concrete pole. Using this, it is verified to compare with previous studies and the nominal strength<TEX>$(M_n)$</TEX> of concrete pole is calculated. It is less than the rupture strength<TEX>$(M_r)$</TEX> of the design standard. Thus, to increase nominal strength, several parameters are selected like as size of tension and reinforced bars, position of those, number of reinforcement bars, thickness of concrete pole, and diameter of it. The effects of those are analysed in the study. It is supposed that section of concrete pole are satisfied rupture strength.
고순도 SiC 미분말을 적용한 4H-SiC 단결정 성장에 관한 연구
신동근,김병숙,손해록,김무성,Shin, Dong-Geun,Kim, Byung-Sook,Son, Hae-Rok,Kim, Moo-Seong 한국결정성장학회 2019 한국결정성장학회지 Vol.29 No.6
개선된 열탄소환원법으로 합성된 금속불순물함량 1 ppm 이하의 고순도 SiC 미립 분말을 이용하여 2,100℃ 이상고온의 RF 가열 PVT 장치에서 SiC 단결정을 성장시켰으며, In-situ x-ray 이미지 분석을 통해 성장과정 중 분말의 승화거동 및 단결정 성장거동을 관찰하였다. SiC 분말은 단결정 성장의 공급원으로 온도가 높은 외곽 부분부터 소진되고 graphite 잔여물이 남았다. 성장 중 원료의 흐름은 가운데 부분으로 집중되었으며 SiC 단결정의 성장거동에도 영향을 미쳤는데, 이는 미립분말로 인한 도가니 내부 온도분포 차이가 원인으로 예상되었다. 단결정 성장이 완료된 후, 단결정 잉곳을 1 mm 두께의 단결정 기판으로 절단하고 또한, 잉곳에서 얻어진 단결정 기판은 전반적으로 짙은 황색의 4H -SiC가 관찰되었으며, 외곽에 일부 발생한 다결정은 시드결정을 시드홀더에 부착하는 과정에서 혼입된 기포층과 같은 불순물 혼입이 원인으로 사료된다. High purity SiC fine powder with metal impurity contents of less than 1 ppm was synthesized by improved carbothermal reduction process, and the synthesized powder was used for SiC single crystal growth in RF heating PVT device at temperature above 2,100℃. In-situ x-ray image analyzer was used to observe the sublimation of the powder and single crystal growth behavior during the growth process. SiC powder was used as a source of single crystal growth, exhausted from the outside of the graphite crucible at the growth temperature and left graphite residues. During the growth, the flow of raw materials was concentrated in the middle and influenced the growth behavior of SiC single crystals. This is due to the difference in temperature distribution inside the crucible due to the fine powder. After the single crystal growth was completed, the single crystal ingot was cut into a 1 mm thick single crystal substrate and finely polished using a diamond abrasive slurry. A dark yellow 4H-SiC was observed overall of single crystal substrate, and the polycrystals generated in the outer part may be caused by the incorporation of impurities such as the bubble layer mixed in the process of attaching the seed crystal to the seed holder.
신동근,윤기용,이승현,강영종,Shin. Dong-Geun,Yoon. Ki-Yong,Lee. Seung-Hyun,Kang. Young-Jong 한국방재학회 2007 한국방재학회 학술발표대회논문집 Vol.2007 No.1
We analyzed the sloped ground safety factor, which is not presented in the design specification, using a computational analysis program L-Pile Plus 13.8. To achieve this we chose a required parameter set and a level ground safety factor presented in the design specification, and then determined its values comparing with the change of the safety factor according to the parameter. Using these parameters, we estimated the sloped ground safety factor for the slope of 35 degrees considering the improvement value of the slope presented in the design specification. As a result of this analysis, we obtained the smaller safety factor by about 0.7 times than the case of the level ground and verified that a number of concrete poles fail to assure 1 degree of the safety factor. We, therefore, concluded that an adjustment of the embedment depth is required in the case of the sloped ground.
콘크리트 전주의 근입깊이 증대를 위한 보강장치의 실험적 성능평가
신동근,윤기용,이승현,이규세,강영종,Shin. Dong-Geun,Yoon. Ki-Yong,Lee. Seung-Hyun,Lee. Gyu-Se,Kang. Young-Jong 한국방재학회 2008 한국방재학회 학술발표대회논문집 Vol.2008 No.1
For reinforcing the overturn of concrete pole instituted in slope ground and weak ground, in this paper, develop the reinforcing installation. The installation increase penetration depth and effect of increasing the penetration depth is verified by experimental paper of Lim, jong suk(2004). In this research, through the experiment of bending test using the reinforcing installation, evaluate the performance. In the result of experiment, concrete pole behave elastically in design load and all sample are safe up to failure load.
신동근(Shin, Dong-Geun),윤기용(Yoon, Ki-Yong),이승현(Lee, Seung-Hyun),이규세(Yi, Gyu-Se),강영종(Kang, Young-Jong) 한국산학기술학회 2007 한국산학기술학회 학술대회 Vol.- No.-
본 연구에서는 설계기준에 제시된 평지 전도 안전율 계산식을 바탕으로 경사지에서의 지반의 저항모멘트를 산정하기 위해 범용 해석 프로그램 L-Pi1e P1us13.8을 사용하여 기존 연구와 검증하고 지반의 일반적인 토질상태별 특성을 고려한 내부마찰각, 접착력, 흙의 단위중량, 지반종류, 사질토 및 점성토 지반계수를 적용하여 각 전주의 근입깊이에 따른 지반의 저항모멘트를 산정하였다. 또한 토질등급에 따른 토질의 상태별 특성이 고려된 4가지 경우를 선정하여 12m 중하중용 전주를 대상으로 경사지의 경사각을 0°~35° 까지 5°씩 증가시켜 지반의 저항모멘트를 산정하였다. 그 결과 경사지 경사각에 따른 저항모멘트가 감소하는 것을 확인 할 수 있었으며 그에 따른 경사지의 근입깊이 증가가 필요한 것으로 판단된다.
Ti-PCS 혼합용액의 전기방사를 통해 제조된 TiO2-SiO2 나노복합 섬유
신동근 ( Dong Geun Shin ),진은주 ( Eun Ju Jin ),이윤주 ( Yoon Joo Lee ),권우택 ( Woo Tek Kwon ),김영희 ( Younghee Kim ),김수룡 ( Soo Ryong Kim ),류도형 ( Doh Hyung Riu ) 한국화학공학회 2015 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.53 No.3
Nanostructured TiO2-SiO2 materials have widely been used as anti-reflecting coating, optical-chemical sensors and catalysts because of their superior optical and thermal properties as well as chemical durability. Web type SiO2 microfibers with nano-crystalline TiO2 were prepared by electrospinning of Ti-PCS mixed solution and oxidation controlled heat-treatment, rather simple than sol-gel process. Nano-crystalline anatase phase were formed for the heattreatment up to 1200 °C and they were finely dispersed in the amorphous SiO2 matrix.
신동근(Shin, Dong-Geun),윤기용(Yoon Ki-Yong),이승현(Lee Seung-Hyun),이규세(Yi, G.S.) 한국산학기술학회 2007 한국산학기술학회논문지 Vol.8 No.4
본 연구에서는 설계기준에 제시된 평지 전도 안전율 계산식을 바탕으로 경사지에서의 지반의 저항모멘트를 산정하기 위해 범용 해석 프로그램 L-Pile Plus13.8을 사용하여 기존 연구와 검증하였다. 지반의 일반적인 토질상태별 특성을 고려한 내부마찰각, 점착력, 흙의 단위중량, 지반종류, 사질토 및 점성토 지반계수를 적용하여 각 전주의 근입 깊이에 따른 지반의 저항모멘트를 산정하였다. 또한 토질등급에 따른 토질의 상태별 특성이 고려된 4가지 경우를 선정하여 12m 중하중용 전주를 대상으로 경사지의 경사각을 0℃-35℃까지 5℃씩 증가시켜 지반의 저항모멘트를 산정하였다. 그 결과 경사지 경사각에 따른 저항모멘트가 감소하는 것을 확인 할 수 있었으며 그에 따른 경사지의 근입깊이 증가가 필요한 것으로 판단된다. In this study, for the purpose of estimating the resistmg moment of sloped ground based on level ground fall down safety equation in design specification, compute it depends on penetration depth of concrete pile applying modulus of foundation about the angle of internal friction, cohesion, unit weight of soil, classes of the ground, sandy or clay soil, and verify established study using L-Pile Plusl3.8. Also, select four cases that characteristics of soil depending on the soil grade is considered and compute the 12m length concrete pile's resisting moment of the ground those angle is changing from 0℃~35℃, step 5℃. In the result, identify that the resisting moment of ground decreases depending on ground slope. Thus, increasing of penetration depth is required.