• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.1
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• pp.26-32
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• 2003

Then-channel poly-Si thin-film transistors (poly-Si TFT's) formed by solid phase crystallization (SPC) method on glass were measured to obtain the electrical parameters such as of I-V characteristics, mobility, leakage current, threshold voltage, and subthreshold slope. Then, devices were analyzed to obtain the reliability and appliability on TFT-LCD with large-size and high density. In n-channel poly-Si TFT with 5$\mu\textrm{m}$/2$\mu\textrm{m}$, 8$\mu\textrm{m}$, 30$\mu\textrm{m}$ devices of channel width/length, the field effect mobilities are 111, 116, 125 $\textrm{cm}^2$/V-s and leakage currents are 0.6, 0.1, and 0.02 pA/$\mu\textrm{m}$, respectively. Low threshold voltage and subthreshold slope, and good ON-OFF ratio are shown, as well. Thus. the poly-Si TFT's used by SPC are expected to be applied on TFT-LCD with large-size and high density, which can integrate the display panel and peripheral circuit on a targe glass substrate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.3-7
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• 2003

Usually, the thrust is calculated by magnetic equivalent circuit modelling method for thrust capacity and accuracy progress of position control about a Linear Pulse Motor of which position precision is good and open-loop control is possible within Linear Motors. Analytical thrust deviation exists to calculating magnetic flux density by using Permeance Modelling Method, Finite Element Method, and Velocity Electric Motive Force Method. For calculating accuracy thrust by using these every method, the thrust is calculated and compared by Lorentz Force Method, Magnetic Coenergy Method, and Maxwell correspondence force Method. And that becomes important factor at the comparison of each capacity and parameter of Motor. So this study wants to compare and analyze measurement data and calculating data of the static force of Linear Pulse Motor. and then we can get more accuracy method, calculating the static thrust of Linear Pulse Motor(LPM).

• Journal of the Korean Applied Science and Technology
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• v.25 no.1
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• pp.52-57
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• 2008

In the present study, impedance characteristics for AgO-Zn cell at various State-of-Charge (SoC) has been studied. The impedance measurements of AgO-Zn cell at various SoC were made over the frequency range from 100kHz to 10mHz with an amplitude 5mV. The impedance parameters have been evaluated by the analysis of the data using an equivalent circuit and a Non-linear least squares (NLLS) fitting method. The total resistances reflects the SoC of the cell. This indicates that the total resistance is important parameter for predicting SoC of AgO-Zn cell.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.9
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• pp.78-85
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• 2000

A new analytical VLSI interconnect delay model is presented and its accuracy is experimentally verified. In the model, the transmission line parameter variations due to skin effect, proximity effect, and silicon substrate effect are taken into account. That is, the circuit model of the interconnect line that includes these effects is newly developed and analyzed. For the model verification, test patterns combined the coplanar structure with microstrip were designed by using 0.35${\mu}m$ CMOS process technology. It is shown that the accuracy of the model is less than about 10% error.

• Journal of electromagnetic engineering and science
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• v.11 no.4
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• pp.298-303
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• 2011

A capsular endoscope (CE) for inspection of the large intestine requires a motor for backward navigation against the autonomous travel in the intestine. This study proposes an HF power system for generating a magnetic field and for delivering wireless power to the internal or implanted medical devices. The magnetic field is generated by a wound coil (L) around a wooden frame, and the current is driven to the coil through a resonating capacitor (C). The characteristics of the resonance frequency shifting of the L-C series circuit are analyzed. A stable magnetic field intensity in the field coil is maintained by a specially designed frequency tracking system that automatically follows the L-C resonance frequency. Testing confirmed that the oscillation system tracks well the parameter changes of the electric components caused by the operating conditions or environmental variations.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.225-231
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• 2009

In this paper, it is shown that Carson's equation can still be applied for the calculation of the series reactance of transmission lines with no ground return current as well as the one with ground return. It is proved in the following method. First two voltage drop equations for three-phase three wire transmission line are derived, one without considering ground return and the other using Carson's equation. The impedance matrix of the two equations are different from each other. But if we put the condition of zero ground current, $I_a+I_b+I_c=0$, those two equations becomes the identical equations. Therefore even a transmission line is not grounded, its line parameters can still be obtained using the Carson's equation. It has been confused whether or not Carson's equation can be used for an ungrounded system. It is because where ever Carson's equation is shown in the book, it also says that the system has ground return current paths as a premise. It is also verified with EMTP studies on the test circuit.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3C
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• pp.271-278
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• 2003

In this paper, we propose a new MLP based detector which has low circuit complexity and fast adaptation capability for CDMA downlink in frequency selective fading, and is easy for parameter optimization. The simplified structure of the proposed MLP is designed by making use of transmission characteristics of downlinks such that all users signals transmitted over same propagation paths and the number of channelization codes are limited. Significant performance improvement over Rake receiver can be obtained with the proposed MLP and the efficiency of the proposed MLP was compared with that of conventional MLP.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2113-2115
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• 2000

It is necessary to install the arc generation facility in order to obtain the important technology for the design of breakers and switches, and for the improvement of their performance and reliability. With this facility, it is possible, to study the characteristics of Arc in air/gas/vacuum insulation environment. The facility briefly consists of capacitor bank which can charge enormous energy, an air-core reactor, experimental arc-chamber, and several measurement equipments. This facility can simulates the arc phenomena in breakers and switches by means of generating high currents. In order to study the arc phenomena in SF6 gas and vacuum and to test the quenching performance of the extinguishing chambers which are developing. we made experimental $SF_6$gas/vacuum chambers and measured several parameter's of chambers. And besides we visualized arc ignition and arc movement by means of high speed camera.

• Corrosion Science and Technology
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• v.6 no.1
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• pp.7-11
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• 2007

In this study, new evaluation method for the stability and corrosion resistance properties of passive films has been suggested by means of observation of self-activation process in open-circuit state and galvanostatic nanoscale reduction test. The experiments were performed for air-formed oxide film in case of plain carbon steel, and for anodically passivated films formed in aqueous sulfuric acid solutions in case of titanium and 304 stainless steel. From these experimental results, we derived two parameters, $i_{0}$ and $q_{0}$, which characterize the self-activation process and the properties of passive film on a stainless steel surface. The parameter $i_{0}$ was defined as the rate of self-activation, and $q_{0}$, the reduced amount of charge during the self-activation process. In conclusion, it is considered that the stability and corrosion resistance of passive metals and alloys can be evaluated quantitatively by three parameters of $\tau_{0}$, $q_{0}$, and $i_{0}$, which easily obtain by means of observing the self-activation process and galvanostatic nanoscale reduction test.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.8
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• pp.46-52
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• 1994

DC and AC current crowding effects for microwave and high speed bipolar transistors are investigated in detail using a new and accurate measurement technique based on Z-parameter equationa. Using the new measurement technique dc and ac current crowding effects have been explained clearly in bipolar junction transistors. To model ac crowding effects a capacitive element defined as base capacitance (C$_b$), called ac crowding capacitance is added to base resistance in parallel thereby treating the base resistance(R$_b$) as base impedance Z$_b$. It is shown that base resistance decreases with increasing collector current due to dc current crowding and approaches to a certain limited value at high collector current due to current crowding and approaches to a certain limited value at high collector currents regardless of the emitter size. It is also observed that due to ac current crowding base capacitance increases with increasing collector current. To quantigy the ac crowding effects for SPICE circuit simulation the base capacitance(C$_b$) including the base depletion and diffusion components has been modeled with an analytical expression form.