• Journal of Integrative Natural Science
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• v.7 no.3
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• pp.183-187
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• 2014

Lead zirconate titanate (PZT) is significant material in electrical and optical devices for their ferroelectric, piezoelectric and dielectric properties. In this research, PZT films were fabricated by reactive RF co-sputtering method using Pb, Zr, and Ti targets. From XPS study, lead, zirconium, and titanium are successfully deposited on Si(100) substrate. Thickness of PZT films was measured with a surface profiler and the thickness was decreased as the oxygen gas ratio increased in the sputter gas.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.276-279
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• 1997

When a magnetostrictive material is exposed to a magnetic field, its geometry changes due to a magnetostrictive effect. The magnetostriction is analogous to the piezoeletricity. The displacement of the magnetostrictive material is proportional to the applied current while that of the piezoelectric material is proportional to the voltage. A magnetostrictive material generates large displacement and higher compressive force compared with a piezoeletric material. These advantages provide a good performance of a vibration isolation of a platform. In this work, it is applied to a driving actuator for vibration isolation of a platform. The properties of a magnetostrictive material are investigated in terms of hysteresis and displacement vs. applied current for a various preload. Modeling of the displacement of the vibration isolating actuator is performed as it behaves as a flow source. A sliding mode controller is designed to demonstrate the ability of the magnetostrictive actuator to reduce the vibration at the platform. The effectiveness of the proposed scheme is demonstrated through experimental works. The experimental results of the vibration of the platform axe presented in terms of time response and frequency response.

• Journal of IKEEE
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• v.22 no.1
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• pp.61-67
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• 2018

We investigated theoretically the magnetic field dependence of the quantum optical transition of qusi 2-Dimensional Landau splitting system, in CdS and ZnO. In this study, we investigate electron confinement by square well confinement potential in magnetic field system using quantum transport theory(QTR). In this study, theoretical formulas for numerical analysis are derived using Liouville equation method and Equilibrium Average Projection Scheme (EAPS). In this study, the absorption power, P (B), and the Quantum Transition Line Widths (QTLWS) of the magnetic field in CdS and ZnO can be deduced from the numerical analysis of the theoretical equations, and the optical quantum transition line shape (QTLS) is found to increase. We also found that QTLW, ${\gamma}(B)_{total}$ of CdS < ${\gamma}(B)_{total}$ of ZnO in the magnetic field region B<25 Tesla.

• Steel and Composite Structures
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• v.29 no.3
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• pp.349-362
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• 2018

Thermal buckling behavior of porous functionally graded nanobeam integrated with piezoelectric sensor and actuator based on the nonlocal higher-order shear deformation beam theory is investigated for the first time. Its material properties are assumed to be temperature-dependent and varying along the thickness direction according to the modified power-law rule. Note that the porosity with even type is considered herein. The equations of motion are obtained through Hamilton's principle. The influences of several parameters (such as type of temperature distribution, external electric voltage, material composition, porosity, small-scale effect, Ker foundation parameters, and beam thickness) on the thermal buckling of FG nanobeam are investigated in detail.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.77-84
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• 2015

PZT ceramics, usually used pyroelectric materials exhibited a relatively highly Curie temperture(Tc) of $250-450^{\circ}C$ and permittivity constant of 500-1600. In this paper, the pyroelectric infrared detectors are applied two different types of pyroelectric materials, that is tetragonal crystal of ferroelectric $PbTiO_3$ and rhombohedral crystal of $Pb(Zr,Ti)O_3$. PZT ceramics shows not only highly Curie temperture but also excellent pyro and piezoelectric properties at the Zr/Ti(=52/48) ratio. Therefor in this paper, the pyroelectric infrared detectors are applied PZT ceramics, and obtained sensitive sensing characteristics by expriment case studies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.22-25
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• 1995

In this paper, the physical characteristics of piezoelectric transducer which generates acoustic weve at microwave frequency were theoretically analized. We found that increasing electrode thickness is showed large distorthion on bandwidth. ZnO thin film were desposited by RF magnetron sputtering method. considering the sputtering parameters. Thickness of the desposited ZnO was 3.9 $\mu\textrm{m}$. In this experiment, we get that resistivity is 12.196${\times}$109 [cm$\Omega$], that resonance frequency is 827.47MHz Measuring insertion loss, we ascertained to possibility of transducer application for microwave frequency.

• Electrical & Electronic Materials
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• v.2 no.1
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• pp.14-24
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• 1989

본 연구에서는 1-3형 PZT/Epoxy 압전복합재료를 제조하고 이에 대한 D-E 곡선, 펄스응답특성 및 유중발생전압특성 등을 조사하였다. 압전복합재료의 음향임피던스는 PZT체적비가 증가함에 따라 비례적으로 증가하였다. 그리고 펄스응답특성은 단일상 PZT의 특성에 비하여 아주 양호하게 나타났으며 PZT 체적비가 40% 이상에서는 펄스응답특성이 거의 일정하게 되었다. 유중에서의 발생전압은 PZT체적비, 시편두께 그리고 유중압력이 증가함에 따란 비례적으로 증가하였다. 이들의 결과는 초음파 트랜스듀서 제작에 좋은 자료가 될 것으로 생각한다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.1
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• pp.31-34
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• 2006

A infrared rays sensor or ultrasonic sensor can detect the object at the narrow area, however a pressure sensor can detect man and animal at the wide area. It is necessary to manufacture the sensor by using Pb-free ceramics in the respect of environmental protection. Piezoelectric properties of ceramics added 0.2wt% $La_2O_3\;into\;0.96Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}+0.04SrTiO_3$ were 0.4 of kp, $31{\times}$10^{-3}Vm/N\;of\;g_{33}$. The output voltage of the pressure sensor is 0.48 V at 20 in$H_2O$. The output voltage of the pressure sensor with driving circuit is 9.8 V, 37 ms width.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.13-16
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• 2005

The mechanical properties of composite materials may degrade severely in the presence of damage. Especially, the high-velocity impact such as bird strike, a hailstorm, and a small piece of tire or stone during high taxing, can cause sever damage to the structures and sub-system in spite of a very small mass. However, it is not easy to detect the damage in composite plates using a single technique or any conventional methods. In this paper, the PYDF(polyvinylidene fluoride) film sensors and strain gages were used for monitoring impact damage initiation and propagation in composite laminates. The WT(wavelet transform) and STFT(short time Fourier transform) are used to decompose the sensor signals. A ultrasonic C-scan and a digital microscope are also used to examine the extent of the damage in each case. This research demonstrate how various sensing techniques, PVDF sensor in particular, can be used to characterize high-velocity impact damage in advanced composites.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.743-748
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• 2008

This paper presents an inertia type of piezostack based active mount for unmanned aero vehicle (UAV) camera system. After identifying the stiffness and damping properties of the rubber element and piezostack a mechanical model of the active mount system is established. The governing equation of mount is them derived and expressed in a state space farm. Subsequently, a sliding mode controller which is robust to uncertain parameters is designed in order to reduce the vibration imposed according to the military specification associated with UAV camera mount system operation. Control performances such as acceleration and transmitted force are evaluated through both computer simulation and experimental implementation.