• Structural Engineering and Mechanics
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• 제74권5호
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• pp.611-633
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• 2020

In this paper, a comprehensive review of nanostructures that exhibit piezoelectric behavior on all mechanical, buckling, vibrational, thermal and electrical properties is presented. It is firstly explained vast application of materials with their piezoelectric property and also introduction of other properties. Initially, more application of material which have piezoelectric property is introduced. Zinc oxide (ZnO), boron nitride (BN) and gallium nitride (GaN) respectively, are more application of piezoelectric materials. The nonlocal elasticity theory and piezoelectric constitutive relations are demonstrated to evaluate problems and analyses. Three different approaches consisting of atomistic modeling, continuum modeling and nano-scale continuum modeling in the investigation atomistic simulation of piezoelectric nanostructures are explained. Focusing on piezoelectric behavior, investigation of analyses is performed on fields of surface and small scale effects, buckling, vibration and wave propagation. Different investigations are available in literature focusing on the synthesis, applications and mechanical behaviors of piezoelectric nanostructures. In the study of vibration behavior, researches are studied on fields of linear and nonlinear, longitudinal and transverse, free and forced vibrations. This paper is intended to provide an introduction of the development of the piezoelectric nanostructures. The key issue is a very good understanding of mechanical and electrical behaviors and characteristics of piezoelectric structures to employ in electromechanical systems.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.333-334
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• 2006

The objective of this study is to fabricate a piezoelectric composite consisting of a piezoelectric ceramic and a high toughness material and to evaluate their electromechanical properties for high force actuator applications. The mixture of the piezoelectric material, PMNZT, and high toughness material, $ZrO_2$, exhibited high piezoelectric properties as well as good mechanical fracture resistance. Up to 2 vol% of $ZrO_2$ in PMNZT matrix, piezoelectric $d_{33}$ coefficient was above 400 pC/N, being 80% of that for the original PMNZT, and the toughness showed twice of the PMNZT. When the volume fraction of the $ZrO_2$ was above 5%, however, the piezoelectric coefficient became abruptly decreased and it approached 20% of value for the PMNZT.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.126-129
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• 1999

Dielectric and piezoelectric properties of perovskite materials such as La modified $Pb(Zr,Ti)O_3$ ceramics and $Pb(Zn_{1/3}Nb_{2/3})O_3-PbTiO_3$ single crystals were investigated for cryogenic capacitor and actuator applications. Enhanced extrinsic contributions resulted in piezoelectric coefficient (d33) as high as 250 pC/N at 30 K, superior to that of PZT ($d_{33}$ ~ 100 pC/N). This cryogenic property enhancement was associated with retuning the MPB (or cryogenic temperatures. PZN-PT single crystals exhibited dramatic property improvements such as $d_{33}$ > 500 pC/N at 30 K as a result of an engineered domain state.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1442-1445
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• 2003

In precision machinery industry, it's required with small size and low noise design to using in constant liquid delivery equipment. To accomplish it's purpose, we designed the check valve with rubber sheet of circle shapes as a possible assembly in pump body. The test equipment for piezoelectric pump was able to test pressure-flow property and output property of piezoelectric pump by variation(magnitude of voltage and frequency) of input power.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.911-914
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• 2005

The vibrational characteristics of the piezoelectric disc for a torsional vibration transducer is theoretically studied in this paper. The characteristic equation of the piezoelectric annular disc has been derived from Newton's End law and Gibb's free energy equations. With an anisotropic material property of the disc, the characteristic equation has yielded resonance frequencies. Numerically-calculated results were compared with the values obtained by finite element analysis and experiments

• 한국분말재료학회지
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• 제23권2호
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• pp.112-119
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• 2016

A powder injection molding process is developed and optimized for piezoelectric PAN-PZT ceramics. Torque rheometer experiments are conducted to determine the optimal solids loading, and the rheological property of the feedstock is evaluated using a capillary rheometer. Appropriate debinding conditions are chosen using a thermal gravity analyzer, and the debound specimens are sintered using sintering conditions determined in a preliminary investigation. Piezoelectric performance measures, including the piezoelectric charge constant and dielectric constant, are measured to verify the developed process. The average values of the measured piezoelectric charge constant and dielectric constant are 455 pC/N and 1904, respectively. Powder injection molded piezoelectric ceramics produced by the optimized process show adequate piezoelectric performance compared to press-sintered piezoelectric ceramics.

• 한국전자통신학회논문지
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• 제7권6호
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• pp.1315-1320
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• 2012

본 연구에서는 분극의 이방성이 없는 ring-dot형 적층형 압전 변압기를 이용한 압전 AC-DC 컨버터를 개발하였다. 동작주파수 범위가 매우 좁은 압전 변압기의 특성을 고려하여 압전 컨버터는 발진주파수의 피드백 제어를 위한 PFM 구동방식과 출력제어를 위한 PWM 구동방식을 이용한 혼합형 구조로 설계되었다. 개발된 압전 컨버터의 최소 발열을 동반하는 안정적 구동을 보이는 최대전력 값은 25W였으며 허용전류 값은 약 900mA이었다. 압전 컨버터의 출력전압의 크기는 구동 발진주파수의 크기에 따라 제어가 가능하였으며, 최대전력에서 효율적이고 안정적인 동작특성을 나타내었다.

• 센서학회지
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• 제31권5호
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• pp.286-292
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• 2022

As mobile electronics become smarter, higher-level security systems are necessary to protect private information and property from hackers. For this, biometric authentication systems have been widely studied, where the recognition of unique biological traits of an individual, such as the face, iris, fingerprint, and voice, is required to operate the device. Among them, ultrasound fingerprint imaging technology using piezoelectric materials is one of the most promising approaches adopted by Samsung Galaxy smartphones. In this review, we summarize the recent progress on piezoelectric ultrasound micro-electro-mechanical systems (MEMS) transducers with various piezoelectric materials and provide insights to achieve the highest-level biometric authentication system for mobile electronics.

• 한국구조물진단유지관리공학회 논문집
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• 제11권2호
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• pp.103-108
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• 2007

본 연구에서는 압전 특성과 표면전위계를 이용한 응력측정 방법을 제안하였다. 다시 말하면 이 응력측정방법은 압전소자에서 발생한 전위를 표면전위계로 측정하게 하는 방법으로서, 이 표면전위는 구조물 부재의 변형률에 비례한다는 특성을 이용하여, 구조물 부재의 각 위치에서의 발생하는 응력을 변형률로부터 계산할 수 있게 된다. 또한, 구조물 부재의 응력분포를 보다 간편하게 구하기 위해서 비접촉 측정법을 이용한 응력분포 측정 Tape를 제작하였다. 특히, 이 Tape는 균열이나 홈과 같이 이상응력 발생 가능한 위치에서의 ${\sigma}_x$, ${\sigma}_y$, ${\tau}_{xy}$의 응력을 측정 뿐만 아니라 국부 응력해석에 활용되었고 그 적용성을 검토하기 위해서 홈이 있는 실험편에 대해서 반복하중 시험결과와 FEM 해석의 결과와 비교 분석하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.226-229
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• 2005

In this study, a step-down piezoelectric transformer was fabricated to utilize as an adapter for charging batteries of mobile electronic appliances. The ceramic part of the transformer is $Pb[(Mn_{1/3}Sb_{2/3})_{0.05}Zr_{0.475}Ti_{0.475}]O_3$ with mechanical quality factor of 1600, electromechanical coupling coefficient 59 %, and piezoelectric constant d33 1300, which can be utilized as a piezoelectric transformer. A simply fabricated disk-typed test pattern of diameter 28 mm and thickness 2 mm was used to characterize resonant frequency, Qm, kp according to the different input/output electrode area. efficiency and power as a function of load resistance was also investigated. The sample APT showed some spurious mode and BPT showed better frequency property. Taking all properties which are admittance, effective electromechanical coupling coefficient and mechanical quality factor most suitable for piezoelectric transformer is BPT which has 12 mm diameter electrode and the condition of 15 Vrms, 30 $\Omega$ made the maximum efficiency of 93.7 % and maximum power is 6W with 50 Vrms.