• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 춘계학술대회 논문집
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• pp.15-18
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• 1993

Piezoelectric Actuator and electrostrictive Actuator samples were fabricated using PMN-PT-PZ system ceramics with Barium substitution, and the strain properties of them investigated. The largest Piezoelectric coefficient and electromechanical coupling coefficient were observed at sintering temperature $1250^{\circ}C$, Barium 0.05 mol %. The strain of poled samples is observed twice highly then unpoled ones, and the former showed larger hysteresis in strain then the latter, too. Poled multilayered actuator samples showed considerable strain.

• 정보저장시스템학회논문집
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• 제1권1호
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• pp.84-92
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• 2005

This work presents the feasibility of shunt damping far vibration suppression of the rotating HDD disk-spindle system using piezoelectric bimorph. A target vibration mode which significantly restricts the recording density increment of the drive is determined through modal analysis and a piezoelectric bimorph is designed to suppress unwanted vibration. After deriving the two-dimensional generalized electromechanical coupling coefficient of the shunted drive, the shunt damping of the system is predicted by simulating the displacement transmissibility using the coefficient. In addition, optimal design process using sensitivity analysis is undertaken in order to improve the shunt damping of the system. The effectiveness of the proposed methodology is verified through experimental implementation by observing the vibration characteristics of the rotating disk-spindle system in frequency domain.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.331-334
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• 1998

The solid solutions of the Pb(Sc$\_$0.5/Nb$\_$0.5/)$\_$0.57/Ti$\_$0.43/O$_3$ system were prepared. In the PSNT system, it had been known that two-phase region between the rhombohedral and tetragonal phases was observed between 0.425 of PT at room temperature. In this paper, Fe$_2$O$_3$-doped 0.57PSN-0.43PT composition was prepared by conventional method. The dielectric and strain properties were examined using an computerized measuring apparatus, and the resonance characteristics were measured using an impedance gain phase analyzer. We got the data of dielectric constant, dielectric loss, piezoelectric coefficient, piezoelectric voltage coefficient, frequency constant strain constant mechanical quality factor and electromechanical coupling factor.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.229-233
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• 2000

In this study, the temperature coefficient of resonant frequency($TCF_r$), dielectric and piezoelectric properties of $Pb_{1-x}Sr_x[(Sb_{1/2}Nb_{1/2})_{0.035}(Mn_{1/3}Nb_{2/3})_{0.065}(Zr_{0.49},Ti_{0.51})_{0.90}]O_3$ ceramics were investigated with the Sr substitution to Pb site. The dielectric constant was increased according to the increase of Sr substitution and electromechanical coupling factor($k_t$) also showed the highest values of 0.485 when the Sr substitution was 5 mol%. Moreover, the mechanical quality factor($Q_{mt}$) showed the highest value of 233 when the Sr substitution was 2 mol%.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1368-1369
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• 2006

In this thesis, the minuteness structure, piezoelectric, and dielectric characteristics of Pb[(Co0.5 W0.5) 0.03 (Ni1/3 Nb2/3) 0.07(Zr0.52 Ti0.48)0.9]O3+0.5Wt% MnO2 ceramics has been systematically investigated as a function of the sintering temperature after manufacturing the specimens with a general method. The electromechanical coupling coefficient (Kp) showed its maximum of 31.116[%] in the sintered specimens at $1050[^{\circ}C]$, and its minimum of 20.220[%] in the sintered specimens at $1150[^{\circ}C]$. The mechanical quality coefficient (Qm) marked the maximum of 139.526 at the sintering temperature of $1150[^{\circ}C]$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1906-1908
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• 2005

In this study, in order to develop the low temperature sintering ceramics, PMW-PNN-PZT ceramics adding CuO, $B_2O_3$ were manufactured, and their piezoelectric properties is investigated. The results of this study were gotten such as follows. The electromechanical coupling coefficient(kp) showed good properites on the whole, showed its maximum value 36.88 in specimens sintered at $900[^{\circ}C]$, 10[mol%] $B_2O_3$. The mechanical quality coefficient(Qm) showed its maximum value 161.601 in specimens sintered at $1100[^{\circ}C]$, 15[mol%] $B_2O_3$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.1113-1115
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• 1993

Piezoelectric Actuator samples were fabricated using PMN-PT-PZ ceramics with Barium substitution, and the strain properties of them were investigated. The tartest Piezoelectric coefficient and electromechanical coupling coefficient were observed at the sintering temperature $1250^{\circ}C$, Barium 5mol%. In the case of Multilayered specimens, they showed considerable strain and small hysteresis than single round type.

• 대한전자공학회논문지SD
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• 제42권1호
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• pp.9-17
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• 2005

공진주파수 스펙트럼법을 이용하여 ZnO 와 AIN 압전박막의 임피던스 특성 및 전기기계결합계수 특성에 대해 조사하였다. 압전박막의 두께가 얇을수록 전체적인 임피던스 응답 피크의 크기가 감소하였으며, 기판의 두께가 얇을수록 응답 피크의 모드 수가 감소하는 것이 관찰되었다. 입력 Kt² 값으로부터 평가된 Kt² 값을 통해 압전박막의 두께보다 기판의 두께 변화에 대한 영향이 더 큼을 알 수 있었고, 기판의 acoustic 임피던스에 의해서도 Kt² 값이 감소함을 알 수 있었다. 전극 효과가 첨가되면 임피던스 응답 피크의 크기가 감소하였으며, 전극의 acoustic 임피던스가 커짐에 따라 응답피크는 더 작아졌다. 공진주파수 스펙트럼법에서 전극은 질량부하로 고려되기 때문에 전극 효과가 첨가된 경우 Keff² 값은 증가하며, 전극의 acoustic 임피던스가 크면 그 효과는 더 커졌다. 공진주파수 스펙트럼법을 이용한 시뮬레이션을 통해 기판, 압전체, 전극으로 이루어진 composite 공진기의 특성 분석과 설계까지도 가능함을 알 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.477-480
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• 2004

We studied the characteristics of impedance and electromechanical coupling coefficient in ZnO and AIN thin films by using resonance frequency spectrum method. The response peak of impedance decreased with the decrease of thickness of piezoelectrics, the number of mode of response peak increased with the increase of substrate thickness. An error of $k_{t}^{2}$ estimated from input $k_{t}^{2}$ increased as the thickness of piezoelectrics decreased and the thickness of substrate increased. Also, the error was increased in case of a large acoustic impedance of substrate. It was found that the composite resonator operating in optimized condition could be designed through the resonance frequency spectrum analysis of composited resonator consisted of piezoelectric thin film and substrate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.164-164
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• 2009

A multilayer piezoelectric transformer(MPT) for step-down voltage was made by ceramic stack process. And then, the characteristics of piezoelectric transformer, such as resonance frequency, matching impedance, electro-mechanical coupling coefficient, voltage gain, heat generation and efficiency, are analyzed. The piezoelectric transformer consists of a lead zirconate titanate ceramic with a high electromechanical quality factor. The piezoelectric transformer, with a multilayered construction in the thickness direction, was formed with dimensions 15mm long, 15mm wide and 5mm thick.