• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1066-1068
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• 1993

Magnetostrictive materials are deformed by applying magnetic fields as electrostrictive materials are deformed by applying electric fields. The GMA(Giant Magnetostrictive Alloy: Terfenol-D) shows larger strain and force compared with piezoceramics and SMA. It is expected that the GMA replaces the piezoceramics in various applications. In this paper, the basic properties of GMA and the current trends of its application are introduced.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.2
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• pp.141-147
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• 2024

The measurement of strain under an electric field has been widely employed to comprehend the fundamental principles of electro-mechanical responses in ferroelectric, piezoelectric, and electrostrictive materials. In particular, understanding the strain properties of piezoelectric materials in response to electrical stimulation is crucial for researching and developing components such as piezoelectric actuators, acoustic devices, and ultrasonic generators. This tutorial paper introduces the components and operational principles of the linear variable differential transducer (LVDT), a widely used displacement measurement device in various industries. Additionally, we present the configuration of an experimental setup using LVDT to measure the strain characteristics of ferroelectric, piezoelectric, or electrostrictive materials under the application of an electric field. This paper includes simple measurement results and analyses obtained through the LVDT experimental setup, providing valuable information on research methods for the electro-mechanical interactions of various materials.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.29.2-29.2
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• 2011

B-site substitution with isovalent and donor impurities was compared in terms of the piezoelectric properties of Bi-based ABO3 perovskite ceramics. X-ray diffraction study revealed that both impurities bring about degradation in their ferroelectric properties as well as piezoelectric characteristics. However, there existed a difference between the isovalent and heterovalent impurities that influence a phase transformation of ferroelectric anisotropic-to-electrostrictive pseudocubic symmetry. Based upon analyses including the crystal, microstructure, dielectric, ferroelectric properties, we believed that A-site vacancies in the ABO3 ceramic significantly contribute to a ferroelectric-nonpolar phase transition, which give rise to lead to a giant strains. The present paper will discuss the origin of giant strains in Bi-based perovskite ceramics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.15-18
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• 1993

Piezoelectric Actuator and electrostrictive Actuator samples were fabricated using PMN-PT-PZ system ceramics with Barium substitution, and the strain properties of them investigated. The largest Piezoelectric coefficient and electromechanical coupling coefficient were observed at sintering temperature $1250^{\circ}C$, Barium 0.05 mol %. The strain of poled samples is observed twice highly then unpoled ones, and the former showed larger hysteresis in strain then the latter, too. Poled multilayered actuator samples showed considerable strain.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.120.4-120
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• 2002

$\textbullet$ In order to operate EP actuator, high voltage is applied to that. $\textbullet$ Our previous control algorithm for an EP actuator was PI method with constant gain. $\textbullet$ But this Control method is limitation such as rising time, steady-state error, and settling time. $\textbullet$ A neural network algorithm is proposed for improvement of performance. $\textbullet$ To do this, neural network algorithm changes the gain of PI control. $\textbullet$ In order to efficient drive EP actuator, the gain is changed at some point. $\textbullet$ Neural network method improve the performance of operation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.69-71
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• 2014

MLCCs are used broadly in electronic industry like smart phone and TV. Although they are fabricated in small size and have high capacitance, there are acoustic noise problems to reduce comfort of user. Acoustic noise results from linear piezoelectricity and nonlinear electrostriction of $BaTiO_3$ in MLCC and there are some researches on MLCC vibration under AC electric field. When only AC electric field without DC bias is applied to MLCC, fundamental frequency response is affected by piezoelectricity and second-harmonic frequency response shows electrostrictive vibration. In this study we get vibration shape of MLCC under AC electric field for each frequency and analysis on the mechanism of MLCC vibration affected by piezoelectricity and electrostriction.

• Journal of the Korean Chemical Society
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• v.15 no.2
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• pp.95-105
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• 1971

The apparent molal volumes ${\phi}_v$ of a series of homologous tetraalkylammonium chlorides, $Me_4NCl, Et_4NCl, Pr_4NCl,\;and\;Bu_4NCl$, in a series of isopropanol-water mixtures have been determined at $30^{\circ}C$ from precision density measurements using pycnometers. The values of ${\phi}_v$ extrapolated to infinite dilution give partial molal volumes $\={V}^{\circ}$s which are almost additive for successive homologues and enable one to determine the absolute individual ionic partial molal volumes. The experimental results are discussed in terrns of the varying size and surface charge of the ions and the structure of the binary solvent mixtures. The results indicate that at 0.1 mole fraction isopropanol the maximum structuredness of water causes a minimum in the tetraalkylammonium-cation partial molal volumes, while at 0.2 mole fraction the solvent structure is such that the free volumes is a minimum and the electrostrictive effect of chloride ion is a maximum.

• Electrical & Electronic Materials
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• v.3 no.4
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• pp.339-346
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• 1990

미소변위소자에 적합한 전왜세라믹스를 제조하기 위하여 0.85Pb(Zn$_{1}$3-x/MgxNb$_{2}$3/) $O_{3}$-0.10BaTi $O_{3}$-0.05PbTi $O_{3}$조성으로 Mg(mol%)를 변화시키면서 시편을 제조하고 구조적, 유전적, 전기적 특성 및 온도 안정성을 관찰하였다. 큐리온도는 Mg(mol%)가 증가함에 따라 감소하였고 Mg(mol%)가 0.15일 때 유전상수가 가장 높았으며 완만도는 -3.9, 산만도.DELTA.Tc는 21로 가장 컸다. 전계에 따른 유전상수는 감소하였고 Mg(mol%)가 증가할수록 압전정수 d$_{31}$은 감소하였으나 0.05, 0.10, 0.15일 때는 거의 일정하였다. Mg(mol%)가 0.15까지 증가함에 따라 전왜정수 Q$_{31}$은 감소하였고 그 이상에서는 Mg(mol%)가 1/3일때 가장 컸으며 ES-1시편에서의 AC 60(Hz), 11(kV/cm) 전계(electric field)에 의한 왜형을 253*$10^{-6}$을 나타냈다.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.196-198
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• 1994

The dielectric and electrical properties of $Pb(Mg_{1/3}Nb_{2\3})O_3-PbTiO_3-BaTiO_3$ have been investigated. Perovskite crystalline phase of the specimens are confirmed by XRD at $1270^{\circ}C$. The curie temperature is around $40^{\circ}C$ with the amount of $BaTiO_3$ and $PbTiO_3$. Every specimens shows the slim loop hysteresis curves which is electrostrictive characteristic. The strain vs. applied voltage characteristics exhibits nonlinear relationship, and the specimen of 0.85PMN-0.125PT-0.025BT shows the largest strain.

• Journal of Ceramic Processing Research
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• v.13 no.spc2
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• pp.282-285
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• 2012

Lead-free (Bi0.5Na0.41K0.09)TiO3 (BNKT) multilayer ceramic actuators were prepared using tape-casting and screen-printing techniques. Co-firing behavior of BNKT/AgPd laminates was examined as a function of sintering temperature. It was found that co-firing induced bending and electrical properties were very sensitive to sintering condition. By optimizing sintering conditions, lead-free electrostrictive multilayer actuators with normalized strain Smax/Emax of 266 pm/V have been successfully fabricated, which is promising for lead-free actuator applications.