• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.469-470
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• 2006

Piezoelectric transformers based on lead zirconate titanate(PZT) have been received considerable interest because of their wide potential applications in transformer, oscillator, resonance sensor, actuator, acoustic transducer, as well as active slider for hard disk drives. However, for the applications which need a small power supply such as thin and flat displays, micro-robot, micro-system, it is especially necessary to integrate the passive components because they typically need more than 2/3 of the space of the conventional circuit. So, we have fabricated the piezoelectric micro-transformer to supply energy for micro-systems using PZT thin films and MEMS technologies.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.434-439
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• 1997

This paper presents the active control of a flexible plate vibration. The plate was excited by white noise point force and the control was performed by one or two piezo ceramic actuator bonded to the surface of the plate. An adaptive controller based on filtered-x or multiple filtered-x LMS algorithm was used and the controller was defined by minimizing the square of the response of error sensor. In the experiment, PZT sensor was used as an error sensor while white noise was applied as a disturbance. In the case of multiple channel control, more than 22 dB of vibration reduction was achieved. Results indicate that the vibration of a flexible plate could be controlled effectively when the piezo ceramic actuator was used with multiple filtered-x LMS algorithm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.204-204
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• 2010

A development of device with reduced size and improved sensitivity is highly impotant Pb(Zr,Ti)$O_3$ thin films are widely used both to make actuator and sensor due to their high sensitivity and low cost. In this study, the feasibility of a piezoelectric presssure sensors based on hybrid low-temperaute co-fired ceramic (LTCC) technology were presented. The LTCC diaphragms with thickness of $400\;{\mu}m$ were fabricated by laminating 4 green tapes which consist of alumina and glass particle in an organic binder. PZT thin films were successfully prepared on between top and bottom Au electrode with LTCC substrates using RF magnetron sputtering. In addition, The frequency response characteristics of the sensor under varing pressure has been analysed. by Network Analyser (HP-8722D). A frequency shift range has been obseved from 1.7GHz to 1.8GHz with a good linearity for applied pressure from 0 psi up to 25 psi.

• Journal of the Korean Ceramic Society
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• v.40 no.4
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• pp.385-392
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• 2003

Sol-gel preparation technique using a chemical reaction of metal alkoxides has been widely used for the fabrication of various materials including ceramics. However, its mechanism has been studied till now because a number of chemical ways are possible from various alkoxides and additives. In this study, the mechanism of hydrolysis, condensation, and polymerization of alkoxides were investigated from the fabrication of lead-zirconate-titanate (PbZr$\_$x/Ti$\_$l-x/O$_3$; PZT) thin film that is used as various micro-actuator, transducer, and sensor because of its high electro-mechanical coupling factors and thermal stability. Furthermore, the fabrication process and characteristics of self-patternable PZT film using photosensitive stabilizer were studied in order to resolve the problem of physical damage and properties degradation during dry etching for device fabrication. Using an optimum condition to prepare the self-patternable PZT film, more than 5000 ${\AA}$ thick self-patternable PZT film could be fabricated by three times coating. The PZT film showed 28.4 ${\mu}$c/cm$^2$ of remnant polarization (Pr) and 37.0 kV/cm of coercive field (E$\_$c/).

• Journal of Sensor Science and Technology
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• v.16 no.2
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• pp.120-125
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• 2007

The effect of $MnO_{2}$ as a sintering additive on the microstructures and the piezoelectric properties, especially mechanical quality factor, of 0.05 Pb$(Sb_{0.5}Nb_{0.5})O_{3}$-0.95 Pb$(Zr_{0.52}Ti_{0.48})O_{3}$ (PSN-PZT) piezoelectric ceramics was investigated. The samples were sintered at $1250^{\circ}C$ for 2 h. The crystal structure and surface morphology of the sample were examined using XRD and FE-SEM, respectively. A study on the influence of $MnO_{2}$ additives on the dielectric and piezoelectric properties showed that the $MnO_{2}$-added PSN-PZT system exhibited a high mechanical quality factor and well-situated piezoelectric properties. The optimized results of $d_{33}$ (319 pC/N), $k_{p}$ (55 %), and $Q_{m}$ (751.24) were obtained at 0.2 wt% $MnO_{2}$ added PSN-PZT piezoelectrics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1332-1335
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• 2003

This paper presents the enhancement of oxygen transfer efficiency using the vibrating intravascular lung assist device (VIVLAD) in in-vitro experiments for patients having chronic respiratory problems. The test section was a cylinder duct with the inner diameter of 30 mm. The flow rate was controlled by the pump and monitored by a built-in flow meter. The vibration apparatus was composed of a piezo-vibrator, a function generator. and a power amplifier. The direction of vibration was radial to the fluid flow. Gas flow rates of up to 6 l/min through the 120-cm-Jong hollow fibers have been achieved by exciting a piezo-vibrator. The output of PVDF sensor were investigated by various frequencies in VIVLAD. The experimental results showed that VIVLAD would be enhance oxygen transfer efficiency.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.22.5-22
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• 2001

Robust control of a GFR composite beam with a distributed PVDF sensor and piezo-ceramic actuator is presented En this paper. Modal analysis method and modal coordinates are introduced to obtain the state educations of the structural system. 1st and 2nd natural frequencies are considered In the modeling, because robust control theory which is robustness to structured uncertainty is adopted to suppress the vibration. If the controllers designed by H$\^$$\infty$/ theory do not satisfy control performance, it is improved by ${\mu}$-synthesis method with D-K Iteration so that the ${\mu}$-controller based on the structured singular value satisfies the nominal performance and robust performance.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.11
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• pp.622-626
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• 2000

In this paper, an optical fiber sensor(OF sensor) utilizing the principal of Sagnac interferometer was proposed to detect the discharge signals. The needle-sphere electrode system in insulating oil generated the signals. The performance of OF sensor was checked by sinusoidal calibration signal generated by PZT actuator at 198KHz. The detected discharge signals consisted of acoustic signal and the electrical noise. The noise signal could be removed by digital low pass filter. It was demonstrated that the OF sensor in this research had a possibility to detect the discharge signals in power apparatus.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.245-248
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• 2012

In this paper, the optimized growing conditions of PZT thin films on low temperature co-fired ceramics (LTCC) substrates are studied. The LTCC technology is an emerging one in the fields of mesoscale (from 10 um to several hundred um) sensor and actuator against silicon based technology due to low cost, high yield, easy manufacturing of 3 dimensional structure, etc. The LTCC substrates with thickness of 400 um are fabricated by laminating 100 um green sheets using commercial power (NEG, MLS 22C). The Pt/Ti bottom electrodes are deposited on the LTCC substrates, then the growing conditions of PZT thin films using rf magnetron sputtering method are studied. The growing conditions are tested under various rf power and gas ratio of oxygen to argon. And the crystallization and ingredient of PZT films are analyzed by X-ray diffraction method (XRD) and energy dispersive spectroscopy (EDS). The optimized growing conditions of PZT thin films are rf power of 125W, Ar/O2 gas ratio of 15:5.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.3
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• pp.309-316
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• 2011

This paper deals with the experimental study of the vibration suppression of the smart structures. First, a new high-speed active control system is presented using the DSP320C6713 microprocessor. A peripheral system developed is composed of a data acquisition system, A/D and D/A converters, piezoelectric (PZT) actuator/sensors, and drivers using PA 95 for fast data processing. Next, the processing time of the peripheral device is tested and the corresponding test results are provided. Since fast data processing is very important in the active vibration control of the structures, achieving the fast loop times of the control system is focused. The control algorithm using PPF in addition to FIR filter is implemented. Finally, numerous experiments were carried out on the aluminum plate to validate the superior performance of the vibration control system at different control loop times.