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오동언,문경현,류주현,Oh, Dong-On,Mun, Keyong-Hyeon,Yoo, Ju-Hyun 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.7
In this paper, simple AT-cut crystal resonator utilizing $Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}TiO_3$ relaxator ceramics as load capacitator were designed and their frequency-temperature characteristics were investigated. In order to modify temperature dependance of dielectric constant, $Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}TiO_3$ ceramics were manufactured with the variations in Sr substitution. At the composition with $6\;mol\%$ Sr substitution as load capacitator, frequency-temperature characteristics of AT-cut crystal resonators with the series load capacitance were similarly varied as those of cut orientation variation, and also compensated.
PbTiO<sub>3</sub>계 세라믹스를 이용한 3차 진동모드 에너지 트랩형 고주파필터의 전기적 특성
오동언,류주현,윤현상,박창엽,이수호,김종선,정회승 한국전기전자재료학회 2003 전기전자재료학회논문지 Vol.16 No.7
In this paper, 3rd overtone mode energy-trapped filter using modified PbTiO$_3$ system ceramics was manufactured to apply for intermediate frequency(IF) SMD type fillet with splitted electrode and gap size. To investigate the effects of splitted electrode and gap size on filter characteristics of 3rd overtone mode energy-trapped filter, ceramic wafers were fabricated by etching splitted rectangular electrode size(b$\times$d) of b=0.4, 0.6, 0.8, 1mm, d=0.3, 0.4, 0.5, 0.6mm and gap size(c) c=0.2, 0.3, 0.4, 0.6mm, respectively. And then, SMD type ceramic filter were fabricated with the size of 3.7$\times$3.1$\textrm{mm}^2$. SMD type ceramic filter with the size of b=0.8mm, d=0.4mm and gap(c)=0.4mm, which showed insertion loss of 2.951dB, 3dB bandwidth of 54.7kHz and 20dB stop bandwidth of 129.27kHz, was suitable for IF bandpass filter application.
전극질량 변화에 따른 SMD형 변성 PbTiO<sub>3</sub>세라믹 공진자의 공진특성
오동언,류주현,박창엽,류성림,김종선,정영호 한국전기전자재료학회 2003 전기전자재료학회논문지 Vol.16 No.3
In this study, modified PbTi $O_3$ ceramics was manufactured to apply for 30MHz SMD type ceramic resonator with the variations of electrode weight. To investigate the effects of electrode weight on resonant characteristics of ceramic resonator using 3$^{rd}$ overtone thickness vibration mode, ceramic wafers for resonator were fabricated by evaporating electrode weights of 0.66, 1.765, 2.32, 3.87$\times$ 10$^{-4}$ g/c $m^2$ with silver, respectively. And then, SMD type ceramic resonators were fabricated with the size of 3.7$\times$3.1mm and electrode radius size of 0.77mm. With increasing electrode weight, resonant resistance was gradually decreased. At the electrode weight of 2.32$\times$10$_{-4}$ g/c $m^2$, mechanical quality factor( $Q_{mt3}$) and dynamic range(D.R) showed the maximum value of 2,152 and 49dB, respectively.
Morphology와 다중 ROI를 이용한 차선 인식 및 추적
오동언(Dong-eon Oh),이민채(Minchae Lee),선우명호(Myoungho Sunwoo) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
Lane detection algorithm have been used for passenger safety systems of luxury vehicle such as the lane keeping assist system (LKAS) and the lane departure warning system (LDWS). In order to enhance the performance of passenger safety systems, robustness and low computation load is required for an effective lane detection algorithm. In previous studies, edge detection, pattern recognition, and probabilistic method have been applied for lane detection. However these approaches have some limitations such as high sensitivity to noise, non-uniform illumination, and high computation load. In this study, we proposed a robust lane detection algorithm using morphology and tracking methods. Morphology is used as a preprocessor for lane detection to reduce the influence of cracked road surfaces and shadows. Moreover, we applied tracking method using multiple regions of interest (ROI) windows to reduce the computation time. In particular, the sizes of multiple ROI were determined by considering the geometric scale effect of the lane mark width. The proposed lane detection and tracking algorithm was evaluated on various road conditions and large scale data. As a result, the proposed algorithm proved to be robust and fast enough to apply to real-time safety-critical systems.
PNW-PMN-PZT세라믹스를 이용한 윤곽진동모드 압전트랜스포머의 전기적특성
류주현,오동언 한국전기전자재료학회 2002 전기전자재료학회논문지 Vol.15 No.7
In this study, microstructural and piezoelectric characteristics of PNW-PMN-PZT ceramics manufactured using attrition milling method were investigated. Sintering temperature of the ceramics was varied from $1080^{\circ}C$ to $1240^{\circ}C$. With increasing sintering temperature, dielectric constant increased. In the specimen sintered at $1120^{\circ}C$, electromechanical coupling factor(Kp) and density showed the maxinum values of 0.546 and 7.78[$g/\textrm{cm}^3$], respectively. In the specimen sintered at $1160^{\circ}C$, mechanical quality factor(Qm) also showed the maxinum value of 1,943. Contour vibration mode piezoelectric transformer with the size of $27.5{\times}27.5{\times}2.5mm$ using PNW-PMN-PZT ceramics was manufactured and its driving characteristics for T5 fluorescent lamp was investigated. Taking into consideration temperature rise of 6.8[$^{\circ}C$] and efficiency of 98.23%, it can be concluded that the transformer is suitable for driving the T5 fluorescent lamp.
Pb(La,Ce)$TiO_3$계 세라믹스의 길이와 두께비($\ell$/t)에 따른 공진특성
민석규,오동언,윤광희,류주현,박창엽,김종선 한국전기전자재료학회 2001 전기전자재료학회논문지 Vol.14 No.9
In this study, Pb(La,Ce)Ti $O_3$ ceramics were manufactured for 20 MHz resonator application. Electromechanical coupling factor( $k_{t}$, $k_{t3}$, mechanical quality factor( $Q_{mt}$ , $Q_{mt3}$ and dydnamic range (D.R) of thickness vibration mode were measured as the variations of $\ell$/t(length/thickness) ratio of ceramic substrates. Mechanical quality factor( $Q_{mt3}$) and dynamic range of third overtone thickness vibration mode showed the highest value of 2,773 and 52.22dB at specimen S4($\ell$/t=12), respectively. The excellent temperature stability of resonant frequency suitable for resonator application was shown, regardless of thermal shock.k.ock.k.
3차 진동모드를 이용한 종속 연결된 고주파 필터 특성에 미치는 결합 캐패시턴스의 영향
류주현,오동언 한국전기전자재료학회 2003 전기전자재료학회논문지 Vol.16 No.10
In this paper, two filters with center frequency of 19.58MHz were cascaded and its bandwidth characteristics were investigated with the variations of coupling capacitance for intermediate frequency (IF) bandpass filter application. The cascaded filter showed the higher stop region, reduction of spurious response and increase of selectivity. With the increase of coupling capacitance, insertion loss was increased but spurious response reduced. The cascaded filter with coupling capacitance of 15pF showed insertion loss of 5.643dB, 3dB bandwidth of 55.089kHz and 20dB bandwidth of 83.608kHz, respectively.
CuO가 PSN-PZT세라믹스의 저온소결 특성에 미치는 영향
류주현,우원희,오동언,정영호,정광현,정문영,정회승 한국전기전자재료학회 2003 전기전자재료학회논문지 Vol.16 No.12
In this study, in order to develop the low temperature sintering ceramics for multi-layer piezoelectric transformer, PSN-PZT system ceramics were manufactured as a function of CuO addition and their dielectric and piezoelectric characteristics were Investigated. CuO addition facilitated densification at low temperature due to the effect of Cu$_2$O-PbO liquid phase. Through the X-ray diffraction pattern study, absence of second phase unwanted was confirmed. Among the specimen to which CuO was added, the 0.6wt% CuO added specimen sintered at 900$^{\circ}C$ and 920$^{\circ}C$ showed the most excellent mechanical quality factor and electromechanical coupling factor, respectively. Besides the densification accelerator, CuO acted as a accepter and increased mechanical quality. Compared with the specimen with no addition sintered at 1150$^{\circ}C$ , the 0.6wt% CuO added specimen sintered at 920$^{\circ}C$ showed the appropriate dielectric and piezoelectric characteristics for multi-layer piezoelectric transformer.
저온소결한 PSN-PZT 세라믹스의 Zr/Ti 비에 따른 압전특성
류주현,우원희,오동언,정영호,정광현,류성림 한국전기전자재료학회 2003 전기전자재료학회논문지 Vol.16 No.12
In this study, in order to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, dielectric and piezoelectric properties of PSN-PZT[0.91Pb(Sb$\sub$1/2/Nb$\sub$1/2/)$\sub$0.03/(Zr$\sub$0.495/Ti$\sub$0.505/)$\sub$0.97/O$_3$-0.04Pb(Ni$\sub$1/2/W$\sub$1/2/)O$_3$+0.05BiFeO$_3$+0.3wt%MnO$_2$+0.6wt%CuO〕 ceramics were investigated according to Zr/Ti ratio. As Zr/Ti ratio is increased, electromechanical coupling factor(k$\sub$p/) and dielectric constant increased and then decreased after the ratio of Zr/Ti=50/50. Also, mechanical qualify factor(Q$\sub$m/) decreased and then increased after the ratio of Zr/Ti=50/50.
CuO가 PSN-PZT세라믹스의 저온소결 특성에 미치는 영향
류주현,우원희,오동언,정영호,정광현,정문영,정회승 한국전기전자재료학회 2003 전기전자재료학회논문지 Vol.16 No.12S
In this study, in order to develop the low temperature sintering ceramics for multi-layer piezoelectric transformer, PSN-PZT system ceramics were manufactured as a function of CuO addition and their dielectric and piezoelectric characteristics were investigated. CuO addition facilitated densification at low temperature due to the effect of Cu2O-PbO liquid phase. Through the X-ray diffraction pattern study, absence of second phase unwanted was confirmed. Among the specimen to which CuO was added, the 0.6wt% CuO added specimen sintered at 900℃ and 920℃ showed the most excellent mechanical quality factor and electromechanical coupling factor, respectively. Besides the densification accelerator, CuO acted as a accepter and increased mechanical quality. Compared with the specimen with no addition sintered at 1150℃, the 0.6wt% CuO added specimen sintered at 920℃ showed the appropriate dielectric and piezoelectric characteristics for multi-layer piezoelectric transformer.