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SOL-GEL법을 이용한 강유전체 BaTiO₃박막 및 Ceramics 제조
조채룡,이수재,장민수,김호종,정세영,노동택,김성철 동의대학교 기초과학연구소 1993 基礎科學硏究論文集 Vol.3 No.1
Concentrated solution was prepared for a sol-gel process of BaTiO₃. Barium hydroxide and Ti-isopropoxide were used as the raw materials with methanol and isopropanol as solvents. Dense ferroelectric polycrystalline BaTiO₃thin films with the perovskite structure were fabricated by spin coating of the prepared concentrated solution on a few substrates. From XRD investigation, it was confirmed that tetragonal phase of polycrystalline BaTiO₃powders are formed after heat treatment above 550℃ in air and grain-oriented BaTiO₃thin films are obtained by coating of 0.06M concentrated solution on the substrates. It was observed that surfaces of thin films deposited on the substrates by our methods were formed crack-free and uniformly. The thickness of thin film which depends the concentration of the solution was 400∼900Å for 1 time coating, which was confirmed by SEM analysis. Ceramics and thin films show dielectric constant of 4600 (at 1㎑) and capacitance 300∼800㎊ (at 1㎑) at room temperature, respectively.
고온용 Nitinol 형상기억합금의 열적/동역학적 특성평가
차수영,박상언,조채룡,박종권,정세영 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-
In the resent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. But, no detailed researches between the thermo-dynamic property in Nitinol alloy have been done yet. In this study, the thermal property of high temperature Nitinol shape memory alloy were evaluated using differential scanning calorimeter(DSC). The structure property was investigated using X-ray diffraction(XRD). A dynamic mechanical analyzer(DMA) with three point bending mode was used to study storage and loss modulus of shape memory alloy according to the thirteen frequencies in the temperature range between 30 and 200℃. The effects of the temperature heating/cooling rate, the frequency on the damping capacity have been systematically investigated. Such a frequency and temperature changes also influenced significantly to the damping behavior of the shape memory alloy. It was also found that Nitinol exhibited high damping capacity during phase transformation.
유기 금속 화학 기상 증착법으로 제조된 자성반도체 Ti1-xCoxO2 박막의 Co 조성 변화에 따른 미세구조 및 자기적 특성
성낙진,오영남,조채룡,윤순길 한국재료학회 2003 한국재료학회지 Vol.13 No.11
Polycrystalline Ti1-xCoxO2 thin films on SiO2 (200 nm)/Si (100) substrates were prepared using liquiddelivery metalorganic chemical vapor deposition. Microstructures and ferromagnetic properties were investigated as a function of doped Co concentration. Ferromagnetic behaviors of polycrystalline films were observed at room temperature, and the magnetic and structural properties strongly depended on the Co distribution, which varied widely with doped Co concentration. The annealed Ti1-xCoxO2 thin films with x0.05 showed a homogeneous structure without any clusters, and pure ferromagnetic properties of thin films are only attributed to the Ti1-xCoxO2 (TCO) phases. On the other hand, in case of thin films above x = 0.05, Co-rich clusters formed in a homogeneous Ti1-xCoxO2 phase, and the overall ferromagnetic (FM) properties depended on both FMTCO and FMCo. Co-rich clusters with about 10-150 nm size decreased the value of Mr (the remanent magnetization) and increased the saturation magnetic field.
성낙진,오영남,조채룡,윤순길,Seong, Nak-Jin,Oh, Young-Nam,Cho, Chae-Ryong,Yoon, Soon-Gil 한국재료학회 2003 한국재료학회지 Vol.13 No.11
Polycrystalline $Ti_{l-x}$ $Co_{x}$ $O_2$thin films on $SiO_2$ (200 nm)/Si (100) substrates were prepared using liquid-delivery metalorganic chemical vapor deposition. Microstructures and ferromagnetic properties were investigated as a function of doped Co concentration. Ferromagnetic behaviors of polycrystalline films were observed at room temperature, and the magnetic and structural properties strongly depended on the Co distribution, which varied widely with doped Co concentration. The annealed $Ti_{l-x}$ $Co_{x}$ $O_2$thin films with $x\leq$0.05 showed a homogeneous structure without any clusters, and pure ferromagnetic properties of thin films are only attributed to the X$l-x_{l-x}$ $Co_{x}$X$O_2$phases. On the other hand, in case of thin films above x = 0.05, Co-rich clusters formed in a homogeneous $Ti_{l-x}$ $Co_{x}$ $O_2$phase, and the overall ferromagnetic (FM) properties depended on both FMTCO and FMCo. Co-rich clusters with about 10-150 nm size decreased the value of Mr (the remanent magnetization) and increased the saturation magnetic field.
Czochralski법을 이용한 금속 단결정의 성장과 구조적, 전기적 성질에 관한 연구
박정훈,차수영,박상언,김성규,조채룡,박혁규,김형찬,정명화,정세영,Park, Jeung-Hun,Cha, Su-Young,Park, Sang-Eon,Kim, Sung-Kyu,Cho, Chae-Ryong,Park, Hyuk-K.,Kim, Hyung-Chan,Jeong, Myung-Hwa,Jeong, Se-Young 한국결정학회 2005 韓國結晶學會誌 Vol.16 No.2
It is well known that the general metals have a lot of grain boundaries. The grain boundaries play a negative role to increase the resistivity and to decrease the conductivity. The small resistivity and the large conductivity have been a goal of the material scientists, and no signal noise, perfect signal transfer, and the realization of the real sound are the dream of electronic engineers and audio manias. Generally, oxygen free copper (OFC) and Ohno continuous casting (OCC) copper cables have been used for the purpose of the precise signal transfer and low noise. However they still include a lot of grain boundaries. In our study, we have grown the single crystal by the Czochralski method and succeeded to produce single crystal wires from the crystal in the dimension of $0.5{\times}0.5{\times}2500mm$. The produced wire still possesses very good single crystal properties. We observed the structure of the wire, and measured the resistance and impedance. Glow Discharge Spectrometer (GDS) was used for analyzing the compositions of copper single crystals and commercial copper. Current-Voltage curve, resistance, total harmonic distortion and speaker frequency response were measured for comparing electrical and acoustic properties of two samples.