• 한국재료학회지
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• 제14권5호
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• pp.334-337
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• 2004

Perovskite PMN-PZT-based ceramics were prepared and the$ MnO_2$ doping effects on their piezoelectric properties were investigated. Grain size decreased with increasing the $MnO_2$ content, and the pyrochlore phase was not identified in the sintered PMN-PZT ceramics with 0.01～1.0wt% $MnO_2$. Piezoelectric voltage and charge constants were reduced and mechanical quality factor increased with increasing the $MnO_2$ content. However, electromechanical coupling coefficient slightly decreased with increasing the MnO$_2$ content without regard to the grain size.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.250-253
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• 1997

Generally, Piezoelectric ceramics based lead-zirconate-titanate(PZT) system are well known to use in high power devices. In this pacer. Pb(Mn$\sub$1/3//Sb$\sub$2/3/)O$_3$(PMS) ceramics which have been shown to be adaptable for a high power usage is introduced. The stability of piezoelectric properties in PZ-PT-PMS solid solution system such as piezoelectric constants. electromechanical coupling coefficient and mechanical quality factor is discussed by the addition effect of CeO$_2$ as a additive. The CeO$_2$ ratio ranges from 0 to 2 wt%. The resonant and anti-resonant frequencies. mechanical quality factor, and force factor are also measured as a function of vibration velocity

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.592-595
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• 2004

This paper presents the feasibility of the piezoelectric shunt damping for vibration suppression of the highly rotating HDD disk-spindle system. A target vibration mode which restricts the recording density increment of the drive is determined by modal analysis of the drive, and a piezoelectric bimorph is designed to suppress the vibration level of the target mode. After deriving the generalized two-dimensional electromechanical coupling coefficient of the shunted spindle-disk system, the damping performance of the system is predicted by simulating the displacement transmissibility on the target mode. After manufacturing the proposed drive, the vibration suppression performance of the proposed methodology is experimentally evaluated in frequency domain.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.976-980
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• 2001

In this study, P $b_{0.88}$(L $a_{a}$N $d_{l-a}$)$_{0.08}$(M $n_{1}$3/S $b_{2}$3/)$_{0.02}$ $Ti_{0.98}$ $O_3$system ceramics were manufactured for 20 MHz class resonator application. Electromechanical coupling factor, mechanical quality factor and dynamic range of 3rd overtone thickness vibration mode were measured as the variations of La and Nd molar ratio. Mechanical quality factor and dynamic range at $\alpha$=0.6 composition ceramics showed the highest value of 2, 691 and 52.37 dB, respectively. The tempearture coefficient of resonant frequency measured from -2$0^{\circ}C$ to 8$0^{\circ}C$ showed an excellent value of 5ppm/$^{\circ}C$ at $\alpha$ = 1 composition ceramics. ceramics.s.

• 한국전기전자재료학회논문지
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• 제15권4호
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• pp.338-343
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• 2002

In this study, $Pb_{0.88}(La_{\alpha}Nd_{1-\alpha})_{0.08}(Mn_{1/3}Sb_{2/3})_{0.02}Ti_{0.98}O_3$ system ceramics with La molar ratio $\alpha$ variation were manufactured for 24 MHz class resonator application. Electromechanical coupling factor, mechanical quality factor and dynamic range of $3^{rd}$ overtone thickness vibration mode were measured as the variations of La and Nd molar ratio. Mechanical quality factor and dynamic range at $\alpha$ = 0.6 composition ceramics showed the highest value of 2691 and 52.37 dB, respectively. The temperature coefficient of resonant frequency measured from $-20^{\circ} to 80^{\circ}$ showed an excellent value of $5ppm/^{\circ}C$ at $\alpha$=1 composition ceramics.

• Korean Chemical Engineering Research
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• 제44권2호
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• pp.166-171
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• 2006

본 연구에서는 전기적 결합 계수가 큰 PMN-PT 압전 재료를 사용하여 탄성표면파를 발진시켜 단백질을 검출할 수 있는 새로운 바이오센서로써 이용 가능성을 확인하고자 시도하였다. 실험결과 PMN-PT 압전 재료의 중심 주파수 필터링은 LT 압전 재료보다 우수하였지만, 만족할만한 결과를 얻을 수는 없었다. 또한, 본 연구에서는 위암을 일으키는 mismatched DNA를 검출하기 위한 방법을 개발하고자 하였다. 그 결과 EDC 용액을 사용하여 NTA에 MutS를 고정화 하였다. 그러나 Ni(니켈)을 사용하여 MutS를 고정화하여 mismatched DNA를 측정하는 것이 더 효과적인 방법이라 판단된다.

• 조명전기설비학회논문지
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• 제20권4호
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• pp.7-11
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• 2006

본 논문에서는 $Mo/SiO_2/Si(100)$ 기판 위에 MOCVD(Metal-Organic-Chemical-Vapor Deposition)법을 이용하여 C축 방향으로 성장시킨 AIN(Aluminum Nitride) 박막을 이용하여 GHz대역 무선 통신에서 사용할 수 있는 FBAR(Film-Bulk-Acoustic Resonator)을 제작하였다. 제작된 공진부의 공진주파수와 반공진주파수는 각각 3.189[GHz]와 3.224[GHz]으로 측정되었으며, Q값(Quality Factor)과 유효한 전기기계 결합계수(${k_{eff}}^2$)는 각각 24.7과 2.65[%]로 평가되었다. AIN의 증착(Deposition) 조건은 $950[^{\circ}C]$의 기판표면(Substrate) 온도, 20Torr의 압력, 25000의 N/Al의 V/III비로 증착하였다. $4{\times}10^{-5}[\Omega{cm}]$의 Mo 하부전극 고유저항과 $Mo/SiO_2/Si(100)$ 기판 위에 AIN(0002) FWHM(Full-Width at Half-Maximum) 4를 갖는 C축 방향성의 AIN 박막을 성공적으로 성장시켰다. 따라서 증착된 AIN박막의 FWHM값은 GHz대역 무선 통신용 RF(Radio Frequency) 밴드 패스 필터 설계에 유용하게 사용될 것이다.

• Smart Structures and Systems
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• 제26권6호
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• pp.681-692
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• 2020

Conventional Piezoelectric Energy Harvesters (CPEH) have been extensively studied for maximizing their electrical output through material selection, geometric and structural optimization, and adoption of efficient interface circuits. In this paper, the performance of Stepped Piezoelectric Energy Harvester (SPEH) under harmonic base excitation is studied analytically, numerically and experimentally. The motivation is to compare the energy harvesting performance of CPEH and SPEHs with the same characteristics (resonant frequency). The results of this study challenge the notion of achieving higher voltage and power output through incorporation of geometric discontinuities such as step sections in the harvester beams. A CPEH consists of substrate material with a patch of piezoelectric material bonded over it and a tip mass at the free end to tune the resonant frequency. A SPEH is designed by introducing a step section near the root of substrate beam to induce higher dynamic strain for maximizing the electrical output. The incorporation of step section reduces the stiffness and consequently, a lower tip mass is used with SPEH to match the resonant frequency to that of CPEH. Moreover, the electromechanical coupling coefficient, forcing function and damping are significantly influenced because of the inclusion of step section, which consequently affects harvester's output. Three different configurations of SPEHs characterized by the same resonant frequency as that of CPEH are designed and analyzed using linear electromechanical model and their performances are compared. The variation of strain on the harvester beams is obtained using finite element analysis. The prototypes of CPEH and SPEHs are fabricated and experimentally tested. It is shown that the power output from SPEHs is lower than the CPEH. When the prototypes with resonant frequencies in the range of 56-56.5 Hz are tested at 1 m/s2, three SPEHs generate power output of 482 μW, 424 μW and 228 μW when compared with 674 μW from CPEH. It is concluded that the advantage of increasing dynamic strain using step section is negated by increase in damping and decrease in forcing function. However, SPEHs show slightly better performance in terms of specific power and thus making them suitable for practical scenarios where the ratio of power to system mass is critical.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.100-102
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• 2001

In this paper, the piezoelectric and dielectric properties of $Pb(Zr_xTi_{1-x)O_3$ - $Pb(Co_{1/3}Nb_{1/3})O_3)$ piezoelectric ceramics have been investigated as a function of Zr/Ti mole ratio. From the results, when Zr/Ti mole ratio is 49/51, electromechanical coupling coefficient($k_p$), piezoelectric strain constant($d_{33}$) mechanical quality factor($Q_m$), and Permittivity(${{\varepsilon}_{33}}^T/{\varepsilon}_0$) is 64[%], 469[PC/N], 360 and 2000, respectively. Morphotropic Phase Boundary is Zr/Ti mole ratio(49/51) from XRD analysis. Also. From SEM observation, when sintering temperature is 1150[$^{\circ}C$], grain size is about $1{\sim}2[{\mu}m]$ and maximum sintering density is 7.85[$g/cm^3$].

• Transactions on Electrical and Electronic Materials
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• 제15권4호
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• pp.226-229
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• 2014

In this study, lead-free $(Ba_{0.85}Ca_{0.15})(Ti_{1-x}Zr_x)O_3$ ceramics and a bimorph-type piezoelectric actuator were fabricated using the normal oxide-mixed sintering method, and their dielectric properties, microstructure, and displacement properties were investigated. From the results of X-ray diffraction, the pattern of the specimen has a pure perovskite structure. In addition, no secondary impurity phases were found. The excellent piezoelectric coefficient of $d_{33}=454pC/N$, the electromechanical coupling factor $k_p=0.51$, the dielectric constant ${\varepsilon}_r=3,657$, the mechanical quality factor $Q_m=239$, and $T_c$(Tetragonal-Cubic) =$90^{\circ}C$ were shown at x= 0.085. ${\Delta}k_p/k_p20^{\circ}C$ and ${\Delta}f_r/f_r20^{\circ}C$ showed the maximum value of -0.255 and 0.111 at $-20^{\circ}C$ and $80^{\circ}C$, respectively. The maximum total-displacement was $60{\mu}m$ under the input voltage of 50 V. As a result, it is considered that lead-free $(Ba_{0.85}Ca_{0.15})(Ti_{1-x}Zr_x)O_3$ ceramics is a promising candidate for piezoelectric actuator application for x= 0.085.