• Journal of Institute of Convergence Technology
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• v.1 no.2
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• pp.6-15
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• 2011

This paper reports the design and fabrication of a micro-electro-mechanical-system(MEMS)-based electrostatic angular microactuator for a dual-stage servo. The proposed actuator employs a novel electrode pattern named "skewed electrode array(SEA)" scheme. It is shown that SEA has better linearity than a parallel plate type actuator and stronger force than a comb-drive based actuator. The moving and the fixed electrodes are arranged to make the driving force perpendicular to the rotating moment of arm. By changing the electrode overlap length, the magnitude of electrostatic force and stable displacement will be changed. In order to optimize the design, an electrostatic FE analysis was carried out and an empirical force model was established for SEA. A new assembly method which will allow the active electrodes to be located beneath the slider was developed. The active electrodes are connected by inner and outer rings lifted on the base substrate, and the inner and outer rings are connected to platform on which the slider locates. Electrostatic force between active electrodes and platform can be used for exiting out of plane modes, so this provides the possibility of the flying height control. A microactuator that can position the pico-slider over ${\pm}0.5{\mu}m$ using under 20 volts for a 2 kHz fine-tracking servo was designed and fabricated using SoG process.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.333-336
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• 2008

We have studied on optical properties of advanced S-IPS with a fine pitch electrode and a new finger design. Transmittance of panel increases with decreasing of width and angle of finger electrode. In order to improve transmittance, fine pitch electrode of ${\sim}2{\mu}m$ and rubbing angle of 10 degree have been adopted. Various optical performances are defined as the function of finger design and field intensify across the IPS pixel electrodes. We have developed the advanced electrode structures with a high performance. As a result, the optical properties of 42" full HD with 120Hz frequency shows high transmittance over 5%, contrast ratio of 1800:1, gray-to-gray response time of 4.4ms, respectively. And also we have studied that the moving picture quality of IPS LCD is related with design parameters of IPS cells and finger shape.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.207-212
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• 2001

Electro-Rheological(ER) fluid are suspensions which show an abrupt increase in rheological properties under electric fields. ER effects arise from electrostatic forces between the starch particles dispersed in the electrically insulating silicone oil, induced when an electric field is applied. Yield stress of the fluids were measured on the couette cell type rheometer as a function of electric fields. This paper presents performance analyses of four types of the two parallel-plate. Which have different electrode length and width but same electrode area. On the basis of the pressure drop and flow rate analysis. Four types of the two parallel-plate are designed and manufactured. Using ER fluid, it is possible to directly interface between electric signals and fluid power without moving parts.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.73-78
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• 2017

A tetrode is one of the neural electrodes, and it is widely used to record neural signals in the brain of a freely moving animal. The impedance of a neural electrode is an important parameter because it determines the signal-to-noise ratio of the recorded neural signals. Here, we developed a modification technique using carbon nanotube-polypyrrole composite nanostructures to decrease the impedances of tetrodes. The synthesis of the carbon nanotube and polypyrrole nanostructures was performed in two steps. In the first step, randomly dispersed carbon nanotubes and pyrrole monomers were gathered and aligned on the tetrode electrode. Next, they were electro-polymerized on the electrode surface. As the applied time (step-1 and step-2) and the offset voltage increased, the impedances of the tetrodes decreased. The modification technique is, therefore, an important and useful of lowering the impedances of tetrodes.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1594-1598
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• 2008

The ionic air pump can be used towards the thermal management of micro-electronic devices, since the size of pump can be reduced to micrometer orders. In addition, an air pump allows air flow control and generation with low noise and no moving parts. These ideal characteristics of the pump give rise to variety applications. However, all of these applications would benefit from maximizing the flow velocities of the pumps. In this study a surface discharge type air pump, with a third electrode, has been investigated by focusing on elevating the wind velocity and efficiency. As a result, the enhanced ionic wind velocity could be obtained with the third electrode of the proposed air pump.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.3
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• pp.432-437
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• 1996

This paper describes a diagnostic technique of power transformers by on-line detection of ultrasonic signals. A trend of partial discharge variation in a real transformer was estimated by counting the number of ultrasonic signals until insulation paper in the point-to-plane electrode is punctured. The number of electrical signals is closely related to the ultrasonic signals generated by partial discharge. The trend of the ultrasonic signal number could easily be distinguished by taking moving average. The insulation failure due to partial discharge in transformers can be predicted based on the trend analysis of ultrasonic signal number caused by partial discharge. (author). 14 refs., 10 figs.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.799-801
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• 2002

To develop GIS (Gas Insulated Switchgear), prediction of the flow field including pressure in GIS is very important. The transport phenomena in GIS including arc is also being studied in these days. In this study, to predict the arc behaviour for GIS with voltage rating up to 800kV developed by HHI (Hyundai Heavy Industries Co. Ltd.), the analysis of flow and electric field in GIS were investigated. To simulate the compressible flow in GIS, the CFX, commercial CFD code, was used. The movement of the piston and the electrode of the GIS was simulated with moving grid method, which was superior to the method of varying the property of cells in the aspect of accuracy and convergence of solution. The calculated maximum pressure within the puffer cylinder was matched with experimental data within 5% error. Also, the oscillation of pressure in GIS after the movement of electrode was well predicted.

• 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.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.11-17
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• 2009

Polarography is a subclass of voltammetry where the working electrode is a dropping mercury electrode. More, I developed the experiment for raising up mercury electrode. In Voltammetry, information about an analyte is obtained by measuring the current as the potential is varied at oxidation-reduction reaction. A plot of current vs. potential in a polarography experiment shows the current oscillations correspoding to the drops of Hg falling from the capillary. The drops growth causes capacitive and faradic current. These changing current effects combined with experiments where the potential is continuously changed can result in noisy traces. The raising up type improved upon the method of dropping in hardware. In reduction of the noise, moving average smoothing method have been used. But the other procedure is introduced based on Fourier transformation. So FFT and IFFT engine was implemented and installed in my experiment. However, after experimentation, peak height as the measuring parameter gave a good linear relationship to concentration. The resolution of potential peaks of various kinds, using Zn and Cu as the example, was improved using the smoothing method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.2
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• pp.57-62
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• 2008

This paper deals with a comparison of individual and connecting grounding electrode for potential rise. When a test current flowed through grounding electrode, potential rise was measured and analyzed for grounding method using a electrolytic tank in real time. In order to analyze the potential rise of grounding systems, a hemispherical water tank experimental apparatus was studied. Potential rise was measured and analyzed regarding the grounding method and distance by using this apparatus. The apparatus was composed of a hemispherical water tank, AC power supply, a movable potentiometer, and test grounding electrodes. The potential rise was measured by the horizontal moving probe of the potentiometer. The grounding electrodes were designed and fabricated with ground rods on a scale of one-eightieth. Potential rises of individual grounding electrode were higher than those of connecting grounding electrode. The distributions of surface potential are dependent on the distance from grounding electrode.