• 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 Microbiology and Biotechnology
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• v.15 no.3
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• pp.587-594
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• 2005

The contribution of electrostriction of water molecules to the stabilization of the negatively charged tetrahedral transition state of a lipase-catalyzed reaction was examined by means of kinetic studies involving high-pressure and solvent dielectric constant. A good correlation was observed between the increased catalytic efficiency of lipase and the decreased solvent dielectric constant. When the dielectric constant of solvents was lowered by 5.00 units, the losses of activation energy and free energy of activation were 7.92 kJ/mol and 11.24 kJ/mol, respectively. The activation volume for $k_{cat}$ decreased significantly as the dielectric constant of solvent decreased, indicating that the degree of electrostriction of water molecules around the charged tetrahedral transition state has been enhanced. These observations demonstrate that the increase in the catalytic efficiency of the lipase reaction with decreasing dielectric constant resulted from the stabilization of electrostatic energy for the formation of an oxyanion hole, and that this stabilization was caused by the increase of electrostricted water around the charged tetrahedral transition state. Therefore, we conclude that the control of solvent dielectric constant can stabilize the tetrahedral transition state, thus lowering the activation energy.

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.87.1-87
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• 2002

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1326-1329
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• 1997

In this paper, PNN-PZN-PZT ceramics were fabricated with various mole ratio of the PZT[$Pb(Zr_{1/2}Tid_{1/2})O_3$]. PNN [$Pb(Ni_{1/3}Nb_{2/3})O_3$] and PZN[$Pb(Ni_{1/3}Nb_{2/3})O_3$ powders prepared by double calcination and PZT powders prepared by molten-salt synthesis method. The formation rate of perovskite phase in PNN-PZN-PZT ceramics could be obtained about 92% at PZT 0.3 mole ratio. The relative permittivity of specimen with PZT 0.3 mole ratio was shown 5,320 and appeared the relaxor ferroelectric feature. The maximum piezoelectric coefficient $d_{31}$ to be used for evaluation the displacement of piezoceramics in PNN-PZN-PZT ceramics was $324{\times}10^{-12}$(C/V) at the vicinity of morphotropic phase boundary and was larger than that of solid PZT ceramics($120{\times}10^{-12}C/V$).

• Journal of the Korean Ceramic Society
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• v.29 no.7
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• pp.572-576
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• 1992

Dielectric constant of ferroelectric ceramics with poling is important in relation to the mechanism of dielectric breakdown. From the research about the dielectric constant variation with poling in tetragonal and rhombohedral phase PZT ceramics, it is known that the dielectric constant after poling is determined by competing effects between increasing effects (compressive stress induced by electrostriction of piezoelectric effects) and decreasing increase in large grain size with poling is smaller than in small grain size.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1348-1350
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• 1994

In this study, various nozzle of ultrasonic spray were designed by using Langevin type electrostriction transducer. The electrical and dynamic characteristics of ultrasonic nozzle with various horn type were investigated. We obtained the average particle size and size distribution profiles with output frequency.

• Journal of the Korean Chemical Society
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• v.13 no.1
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• pp.9-12
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• 1969

Partial molal volumes of anilinium chloride in several methanol-water mixtures have been determined at $30.0^{\circ}C$. The maximum in limiting slopes and the minimum in partial molal volumes at 0.4 mole fraction have been interpreted as the result of maximum electrostriction of the solvent with the minimum free volume.

• Journal of the Korean Chemical Society
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• v.13 no.2
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• pp.121-129
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• 1969

The apparent and partial molal volumes({\phi}\nu$and $V^{\circ}$) of a series of homologous n-alkylamine hydrochlorides $C_nH_{2n+1}NH_3^+Cl^-$, where n varies from zero to four, have been determined by means of a float method at 30$^{\circ}C$ to the fifth decimal place down to 0.01M in aqueous solutions. The experimental results indicate that the partial molal volumes of the salts are almost additive for successive homologues depending on the increment of molecular weight ($CH_2$). It has been observed that the concentration dependence of the ${\Phi}v$ are linear in general and limiting slopes are positive and relatively close to the theoretical values. Anionic partial molal volume of chlorides anion $V^{\circ}_{Cl^-}$ is found to be 18.6 ml $mole^{-1}$, which is in good agreement with the results of other workers. {\phi}\nu$ data also show that in solution the hydrophobic effect of ions are in competition with the charge effect, but the latter, that is, electrostriction seemed to be considerably predominant.

• Polymer(Korea)
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• v.26 no.1
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• pp.113-120
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• 2002

Electrostriction is the phenomenon that a material is strained due to Maxwell stress developed by the applied voltage. In many electrostrictive materials, especially polymeric elastomers can produce large deformation and force due to their low elastic modulus. In this study, polyurethanes and acrylic rubber with compliant electrodes were used as electrostrictive polymer(EP) actuator. Actuation characteristics of the EP actuators with different physical properties of dynamic modulus and dynamic dielectiric constant were analyzed under AC field. The classical laminate theory was also used to simulate the actuation process in relation to the geometry and the physical properties of the actuators.

• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.40-46
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• 1986

Rate constants for the solvolysis of o-methylbenzyl chloride were determined at 30$^{\circ}$ and 40$^{\circ}$C in aqueous ethanol mixtures under various pressures up to 1600 bar. From the rate constants, the activation parameters ${\Delta}V^{\neq}$, ${\Delta}{\beta}^{\neq}$, ${\Delta}H^{\neq}$, ${\Delta}S^{\neq}$ and${\Delta}G^{\neq}$ were evaluated. The values exhibit the extremum behavior at about 0.30 mole fraction of ethanol. This behavior is discussed in terms of electrostriction. To examine the reaction mechanism by Laidler and Eyring equation, we compared the rate constants with the dielectric constants of aqueous ethanol and the number of water molecule participated in the transition state. It was concluded that solvolytic reaction proceeds via $S_N$1 mechanism.