• Current Optics and Photonics
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• v.6 no.2
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• pp.183-190
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• 2022

Based on the linear electro-optic (EO) effect of lithium niobite (LiNbO₃, LN) crystal, an intense two-dimensional (2D) electric field sensor was analyzed, fabricated and experimentally demonstrated. The linear polarized light beam transmits along the optical axis (z-axis) of the LN crystal, and the polarization direction of the polarized light is 45° to the y-axis. The sensor can detect the intensity of a 2D electric field that is perpendicular to the z-axis. Experimental results demonstrated that the minimum detectable electric field of the sensor is 10.5 kV/m. The maximum detected electric field of the sensor is larger than 178.9 kV/m. The sensitivity of the sensor is 0.444 mV/(kV·m^-1). The variation of the sensitivity is within ±0.16 dB when the sensor is rotated around a z-axis from 0° to 360°. The variation of the sensor output optical power is within ±1.4 dB during temperature change from 19 ℃ to 26 ℃ in a day (from 7:00 AM to 23:00 PM) and temperature change from 0 ℃ to 40 ℃ in a controllable temperature chamber. All theoretical and experimental results revealed that the fabricated sensor provides technology for the direct detection of intense 2D electric fields.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.4
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• pp.13-21
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• 2001

Electrorheological(ER) fluid is a kind of smart material with variable shear stress and dynamic viscosity under various electric field intensity. Electric field can control the damping characteristics of ER damper. The objective of this study is the analysis of the performance of ER damper and its application to shock absorber. Idealized nonlinear Bingham plastic shear flow model is used to predict the velocity profile between electrodes. Cylindrical dashpot ER damper with moving electrode is constructed and tested under various electric fields. The analytic and experimental results for damping force are compared and discussed. Drop test system using ER damper is prepared to identify transient vibration characteristics. The rebound is eased as the applied electric field increases. When semi-active control algorithm is applied, rebound phenomenon disappears and vibration energy level decays faster than the case of zero electric field.

• The Korean Journal of Ceramics
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• v.7 no.1
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• pp.30-35
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• 2001

The contribution of the non-$180^{\circ}C$ domains to the electric-field-induced strains (EFI-strains) of PZT ceramics was evaluated by an XRD method and by an interferometric method. The XRD intensity ratio of 200 and 002 diffraction peaks of tetragonal PZT was measured under strong electric fields. The amount of the $90^{\circ}$ domain reorientation was evaluated and the strain due to the domain reorientation was calculated. It was confirmed that the EFI-strain of PZT ceramics was equal to the sum of the strain calculated from the d$_33$ constant determined by the resonance-antiresonance method and the strain due to the $90^{\circ}$ domain reorientation. The amount of the $90^{\circ}$domain reorientation has a linear relation with the c/a ratio in the "soft" PZT ceramics. A Mech-Zehnder interferometer was constructed to measure the EFI-strains vs. electric-field curves of PZT ceramics as a function of frequency. The EFI-strain vs. electric-field curve showed a hysteresis due to the effect of the non-$180^{\circ}$ domain reorientation when the applied voltage was high and its frequency was low. The apparent piezoelectric constant increased from the d$_33$ value determined by the resonance-antiresonance method with decreasing frequency. This deviation was attributed to the non-$180^{\circ}$ domain contribution.tribution.

• Korean Journal of Optics and Photonics
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• v.4 no.3
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• pp.323-329
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• 1993

In this paper, dependence of the diffraction efficiency upon incident light intensity is studied. The conductivity ratio, which is dependent upon the incident light intensity, changes the static electric field in a crystal. This change of the static electric field modulates the refractive index via linear electro-optic effect. And the change of the refractive index affects the diffraction efficiency. It is found that experimental results with $Fe:LiNbO_3$ crystals are in good agreement with the theory.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.3
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• pp.216-220
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• 2013

The rated voltage has been rising in order to minimize the losses in power transmission. The high voltage electric machines should be minimized due to the constraints of space. Therefore, the temperature of high voltage electric apparatuses easily exceeds the temperature limits. In this paper, it is investigated that how to minimize the internal temperature rising of a high voltage switchgear by adjusting the arrangement of bus bars. High voltage switchgears consist of a circuit breaker, a CT, a PT, a earthing switches, bus bars, and so on. It is very difficult to estimate the electromagnetic properties of a high voltage switchgear due to these various environments and structures. In this paper, analyses are focused on the electromagnetic characteristics of bus bars according to the arrangement method and the enclosures to simplify the electromagnetic characteristics of a switchgear. It is found that the characteristics of electric field intensity and electromagnetic losses in bus bars are influenced by the arrangement method of bus bars. However, it is confirmed that the electromagnetic characteristics of enclosures are not affected by the arrangement of bus bars. In this paper, the arrangement methods of bus bars to minimize the electric field intensity and electromagnetic losses are suggested. It is expected that the research results are helpful to design and develop an electrically reliable high voltage switchgear.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.3
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• pp.14-21
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• 1998

In this paper, the measurements of ELF electric and magnetic fields due to double circuit 345[kV} transmission lines are made using planar-type electric field sensor and multitum loop-type magnetic field sensor, and the magnitudes of electric and magnetic fields are illustrated by a three-dimensional plot. Also, in order to predict the magnetic field strength with lad variation, a typical daily load current curves of the transmission lines are displayed because the magnetic field is changed with load current. experimental results of ELF electric and magnetic fields along center line versus lateral distance are compared with the theoretical values computed by using the FIELDS program. The electric field intensity in and around a transmission tower is lowered, and the greatest point of the magnetic field is shifted to the heavy load line but generally is given the trend that the peak value appear at the central part of the transmission tower. The magnitudes of the maximum electric and magnetic fields in the vicinity of a transmission tower are less than 3.5[kV/m] and $20[{\mu}T]$, respectively. The measured electric and magnetic fields are satisfied with limits and guidelines recommended by various authorized international institutes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.297-300
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• 1997

In this study, The PVDF thin film was fabricated on the one method of dry-process the physical vapor deposition method, applied electric field, and evaporation control in $\beta$-PVDF thin film preparation. A study on the electric-field-phase change of PVDF thin film in physical vapor deposition using the polymer deposition apparatus which are manufactured for oneself. In the analysis of Fourier-Transform Infrared spectra, according to increasing of electric field intensity, the 510$cm^{-1}$ / peak and 1273$cm^{-1}$ / peak which are showed in $\beta$-PVDF increase, on the contrary the 530$cm^{-1}$ / peak and 977$cm^{-1}$ / peak which are showed in $\alpha$-PVDF decrease.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.118.3-118
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• 2001

CLED (Contact Light Emitting Device) has three layers consisting of a transparent electrode, a light emitting layer and a substrate. When the substrate of the CLED comes in contact with a fingerprint under AC input voltage, it makes an electric field between the fingerprint and the device. Due to the electric field, the light is emitted along the ridgeline of the fingerprint. The intensity along the ridge on the surface of the CLED increase in proportion to the electric field. To achieve uniform performance of fingerprint verification devices, inspection system of CLED for quality control were required. In this research, we proposed the factors for quality controls such as dimensions of the CLED, uniformity ...

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.575-580
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• 2010

In this work, the electrophoretic motion of dsDNA molecule represented by a polymer through an artificial nano-pore in a membrane is simulated using the numerical method combining the lattice Boltzmann and Langevin molecular dynamic method. The polymer motion is represented by Langevin molecular dynamics technique while the fluid flow is taken into account by fluctuating lattice-Boltzmann method. The hydrodynamic interactions between the polymer and solvent in a confined space with a membrane having a hole are considered explicitly through the frictional and the random forces. The electric field intensity over the space is obtained from a finite difference method. Initially, the polymer is placed at one side of the space, and an electric field is applied to drive the polymer to the other side of the space through the nano-pore. In future, we plan to study the effect of the polymer size and the electric field on the electrophoretic velocity.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.1
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• pp.84-89
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• 2004

This study is a basic one for application of ER Fluid to fluid power systems. By mixing silicone oil with zeolite particles, four kinds of ER fluids were made, in which the weight ratio of zeolite particles are different. We examined how the Yield shear stress and Bingham characteristics of the ER fluids are effected by varying electric field intensity. We designed and constructed a disk type power transmission clutch in which ER fluid fills and this ER fluid transmits the power of drive shaft to the driven shaft. With this equipment, the revolution transmission ratio from the chive shaft to the driven shaft by varying electric field density of the ER fluid was examined.