• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 추계학술대회 논문집
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• pp.139-142
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• 1994

Ceramic filter using energy trapping pheonomenon is used bandpass filter at high frequency. In this paper, we analyzed theoretically ceramic filter characteristics of TS vibrational mode and also investigated experimentally it. The ceramic plate is PZT-4 poled in the thickness direction of Valpey Fisher Co. and electroded with two pairs. We analyzed the characteristics in appling to the all constant of ceramic and electrode material each other and vibrational mode. We also measured resonant frequency and bandpass width of the ceramic filter changing the thickness of ceramic plate and electrode spacing. Comparing of falter characteristics, theoretical value nearly corresponded with experimental value. So we saw that we can expect filter characteristics changing the thickness of ceramic plate and electrode spacing.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.539-543
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• 2014

This work investigated the electromechanical performance of a cantilevered vibration energy harvester incorporating the single crystal PMN-PZT, manufactured with the most recent technology of solid-state single crystal growth. Single crystal PMN-PZTs with two different crystallographic axes such as [011] and [001] were considered. For the [011] orientation, because material properties such as the stiffness, piezoelectric strain coefficients are not the same in the directions normal to the crystallographic axis, the effects of the transversely anisotropy on the magnitude and frequency bandwidth of output power were also analyzed.

• 비파괴검사학회지
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• 제21권4호
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• pp.434-438
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• 2001

봉에서 전파하는 비틀림파를 발생시키는 압전 비틀림 파동 변환기를 제작하였다. 비틀림 파동을 발생시키는 원리는 원주방향으로 분극된 압전 원판에 인가된 두께 방향 전압에 의해 나타나는 원주방향 전단운동이다. 압전 비틀림 원판을 제작한 후, 공진 주파수를 낮추기 위하여 랑주방(Langevin)형 비틀림 변환기를 제작하였다. 제작된 변환기들의 공진 주파수를 측정한 결과, 해석에 의해 예상된 특성과 잘 일치하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.220-223
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• 1987

In this paper, electro-optic characteristics of PLZT 7.6/70/30 composition in MPB regions, which antiferroelectric and ferroelectric phases coexist together, were studied. As sintering times are increased, Curie temperatures ore linearly decreased. And the antiferroelectric phase becomes more stronger when Curie temperatures are decreased. The crystal structure investigated by lie of X-ray analysis is proved to cubic in the thermally depoled specimen and rhombohedral in the poled specimen. Accordingly, the applicability of 7.6/70/30 specimen as image storage and display device is expected by the method for applying field induced reversible transitions between antiferroelectric(AFE) and ferroelectric(FE) phase.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.270-273
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• 1996

This paper describes a type of piezoelectric transformer with improved design principles. It consists of a thin rectangular piezoelectric ceramic plate having two input electrodes and one output electrode. The length of each input and output electrode is nearly one third of that of piezoelectric transformer itself. In the driving section, the ceramic plate is poled in the thickness direction reversely with each other, and has electrodes on both main faces. The electric input near its fundamental resonance frequency is applied to the driving section in parallel and the output voltage from the generating section is connected to the resistor load. Its equivalent circuit is derived from the Mason\`s model. The frequency characteristics near the resonance frequency under no load have been investigated. Moreover, using this piezoelectric transformer we measured the LCD backlight characteristics.

• 한국세라믹학회지
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• 제33권1호
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• pp.49-55
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• 1996

The aim of this study is to investigate the change of bending strength and fatigue strength in the unpoled and poled Pb(Zr, Ti)O3 ferroelectrics of tetragonal morphotropic phase boundary (MPM) and rhombohedral com-position in terms of internal stress which is measured by XRD method. Before poling treatment the highest bending strength was found in rhombohedral composition. After poling treatment the bending strength decreas-ed in all compositions but it decreased most remarkably in tetragonal composition. The most prominent de-crease of bending strength after poling treatment in tetragonal was attributed to the occurrence of microcracks due to highanisotropic internal stress around grain boundary which was induced of bending strength after poling in MPB and rhombohedral composition was not due to the occurrence of microcracks but to the increase in tensile internal stress perpendicular to the direction of crack propagation by domain alignment. Fatigue strength was higher before poling treatment than after poling treatment for various compositions.

• 한국세라믹학회지
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• 제31권3호
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• pp.305-311
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• 1994

In this paper, a change of fracture toughness and hardness in PZT-PYW ceramics system before and after poling treatment was measured to investigate the effect of composition on the mechanical properties in PZT-PYW ceramics. The hardness of the PZT-PYW ceramics increased with increasing mole fraction of PYW. The fracture toughness achieved maximum values for x=0.03. Both of the hardness and the fracture toughness also increased with poling treatment. The variation of both hardness and fracture toughness with increasing PYW mole fracture was explained by the change in microstructures such as grain size and second phase. The difference in hardness and fracture toughness in the electrically poled and unpoled specimens was also explained on the bases of internal stress.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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• pp.228-229
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• 2003

The quasi-phase matching (QPM) technique has dramatically changed the guidelines in developing nonlinear optical materials, which doesn't require birefringence and off-diagonal components for efficient wavelength conversion. Minimum requirement for QPM is the modulation of nonlinearity and ferroelectric materials with low coercive field has become fascinating in periodical poling. Stoichiometric lithium tantalate (SLT) has attractive advantages of low coercive field (∼l .5 KV/mm), high nonlinearity, high optical damage resistance and low thermo-optic coefficients, leading to a large aperture QPM devices for high power operation. (omitted)

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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• pp.224-225
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• 2003

Since group velocity (GV) mismatch significantly limits the efficiency of nonlinear interactions such as second harmonic generation (SHG), several techniques have been developed to compensate GV mismatch. The simplest way to avoid the GV mismatch problem is to reduce the device length. However, it results in a poor trade-off between the SHG spectral bandwidth and the conversion efficiency. (omitted)

• Journal of the Optical Society of Korea
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• 제10권4호
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• pp.188-195
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• 2006

Third harmonic generation microscopy is described in the frame work of the theory of harmonic generation with Gaussian focused beams inside a bulk material as well as at the vicinity of an interface. This model is then applied to characterize different types of materials in terms of electronic third-order susceptibility. Examples of bulk glasses, poled glasses, laser-induced modifications in glasses and nanoparticles in solution are given in order to give a survey of the broad application field of THG microscopy in material characterization.