• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.75-78
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• 2006

An external electrode fluorescent lamps (EEFLs) have the advantage of a long lifetime in the early stages of the study on plasma discharge, interest in the lamp continues. Studies on the operation of external electrode fluorescent lamps have focused mainlyon its use of a type of high frequency (MHz). By performing high brightness using a square wave operation method with the low frequency below 100kHz, which is applied to a narrowed tube type lamp that has several mm of lamp diameter, an EEFL presented the possibility of using it as a light source for backlights. However, because an EEFL generates plasma using wall charges, which considers the impedance characteristics of glass based on the structural principle in discharge, it can be significantly affected by frequency. Thus, this study verifies the change in the characteristics of electromagnetic fields according to the change in frequency through a Maxwell's electromagnetic field simulation and examines the relationship between the change in the EEFL frequency and brightness by measuring the optical. characteristics. In addition, the characteristics of the transformation of energy orbits were verified by investigating the characteristics of the wavelength according to the change in frequency through the OES.

• Geosciences Journal
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• v.22 no.6
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• pp.1027-1039
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• 2018

Seismic attributes are often used to identify lithology and evaluate reservoir properties. However, interpretation based only on structural attributes and without knowledge of the Vp/Vs ratio can limit the ability to evaluate changes in heavy oil reservoirs. These limitations are often due to less obvious impedance differences. In order to investigate pieces of evidence of a heavy-oil shaly-sand reservoir from seismic data, besides geochemistry, we studied seismic attributes and characterized the reservoir using seismic stack data and well logging data. The study area was the Muglad rift basin in South Sudan. We conducted a seismic complex analysis to evaluate the target reservoir. To delineate the frequency responses of the different lithological units, we applied the spectral decomposition method to the target reservoir. The most unexpected result was continuous bands of strong seismic reflectors in the target reservoir, which extended across the borehole. Spectral decomposition analysis showed that the low-frequency zone of 25 Hz dominant frequency was consistent with instantaneous attributes. This approach can identify lithology, reveal frequency anomalies, and filter the stacked section into low- and high-frequency bands. The heavy-oil reservoir zones exhibited velocity attenuation and the amplitude was strongly frequency dependent.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.12
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• pp.1-7
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• 2010

In this paper, we suggested a sensing method of PoRAM with the multilevel cell When a specific voltage is applied between top and bottom electrodes of PoRAM unit cell, we can distinguish cell states by changing resistance values of the cell. Especially, we can use the PoRAM as the multilevel cell due to have four stable resistance values per cell. Therefore, we proposed an address decoding method, sense amplifier and control signal for sensing of a multilevel cell. The sense amplifier is designed based on a current comparator that compared a cell current the cell with a reference current, and have a low input impedance for a amplification of the current. The proposed circuit was designed in a $0.13{\mu}m$ CMOS technology, we verified to sense each data "00", "01", "10", "10" by four states of a cell current.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.761-770
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• 2008

Impedance or admittance inverter is a conceptual 2-port device frequently used in microwave filter design. In this paper, the equivalent circuit using inverter for general loss less 2-port circuit is presented. Our equivalent circuit can be directly and easily represented with z- or y-parameters compared with the conventional methods. Based on the representation, the derived results for various coupled lines such as parallel coupled line and anti-parallel coupled lines are compared ours. In addition, the results of other workers for improvement of the distortion in frequency response of microstrip coupled line filter are derived using our representation and compared. The proposed equivalent circuit shows the difference with conventional equivalent circuit so the conventional design method can not be applied to parallel coupled line filter with our representation. So in this paper the novel design method is proposed and we showed the method yields more accurate design results.

• Journal of Hydrogen and New Energy
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• v.20 no.6
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• pp.485-491
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• 2009

In present work, NiO/YSZ anode functional layer was prepared by nano NiO powder and 8YSZ powder. The nano NiO powders were made by Pulsed wire evaporation (PWE) method. Nano NiO- YSZ functional layer was sintered at the temperature of $900-1400^{\circ}C$. The prepared functional layer was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy. The nano NiO- YSZ anode functional layer sintered at $1300^{\circ}C$ shows the lowest polarization resistance. Nano NiO- YSZ anode functional layer shows about two times smaller polarization resistance than the anode functional layer made by commercial NiO-YSZ powders. Based on these experimental results, it is concluded that the nano NiO-YSZ cermet is suitable as a anode functional layer operated at $800^{\circ}C$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1272-1278
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• 2009

The present paper is purposeful that I compare the materialization method of the filter of UIR and SIR, then make two filters of different methods, so both are useful. The structure of the method of UIR is simple, so it is used a commercial point of view that the client gets the characteristics what he wants. However, the needs of companies when compared to the same standards, a little more cheaply in price, a little smaller in size, better performance characteristics are expected. In this regard, the method of SIR is smaller than UIR in size, but it shows the similar characteristics of UIR, so it is expected that holds a dominant position in competitive power. In this paper, based on these conditions, I compared the methods of SIR and UIR after the design and production. The standards are Insertion Loss is less than 0.8dB, Return Loss is above 20.0dB, and the Ripple is within 0.3dB. The center frequency is settled 881.5MHzband that TX Band is used by CDMA(SKT). I compared in the same conditions in Bandwidth 25.0MHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.29-34
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• 2023

A clear and efficient design method for a microstrip-to-waveguide inline transition, which is based on an analytical model, is presented. The transition consists of three parts: a microstrip-to-SIW transition, a dielectric-loaded waveguide with substrate-height, and a stepped-height waveguide. The shape of the transitional structure is formed for impedance matching. Two equivalent type0s of dielectric-loaded transitional structures are proposed. The design method is applicable to any size of the waveguide, but a design method of two Ka-band transitions is demonstrated. The proposed transitions, in a back-to-back configuration, have less than 1.2 dB insertion loss and more than 15 dB return loss from 29.8 GHz to 38.2 GHz.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.10-15
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• 2017

Research interest has strongly focused on developing a method for effectively transmitting bio-signals over a distance using a wireless wearable device. In this paper, we describe a procedure for the design and fabrication of a wearable antenna based on embroidering conductive threads to clothing capable of transmitting electrocardiogram signals. 3D electromagnetic simulation software and embroidery software were used to design and fabricate the conductive thread-based antenna, respectively. The measurement results show that the reflection coefficient of the fabricated antenna prototype exhibits excellent antenna impedance matching characteristics of less than -10dB in the Zigbee 2.4GHz frequency band. We also verified that the electrocardiogram data could be effectively received and monitored in real-time by a receiver 220m away from the transmitter.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.2
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• pp.137-144
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• 2011

A Simple equivalent circuit model is developed for a wireless energy transfer system via coupled magnetic resonances and a practical design method is also provided. Node equations for the resonance system are built with the method, expanding on the equations for a transformer, and the optimum distances of coils in the system are derived analytically for optimum coupling coefficients for high transfer efficiency. In order to calculate the frequency characteristics for a lossy system, the equivalent model is established at an electric design automation tool. The model parameters of the actual system are extracted and the modeling results are compared with measurements. Through the developed model, it is seen that the system can transfer power over a mid-range of a few meters and impedance matching is important to achieve high efficiency. This developed model can be used for a design and prediction on the similar systems such as increasing the number of receiving coils and receiving modules, etc.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.612-621
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• 2018

In this study, $TiO_2$ nanotube plate and metal electrodes(Copper, Nickel, Stainless Steel, Aluminum, Tin, Titanium) were compared on cathodic reduction of nitrate ($NO_3{^-}-N$) during electrolysis. The electrochemical characteristics were compared based on electrochemical impedance spectroscopy (EIS). The surface morphology was obtained using scanning electron microscopy (SEM) method. Brunauer-Emmett-Teller (BET) method was implemented for the specific surface area analysis of the cathodes. To study kinetics, 90 minute batch electrolysis of nitrate solution was performed for each cathodes. In conclusion, under the condition of relatively low ($0.04 A\;cm^{-2}$) current density, $TiO_2$ nanotube plate showed no surface corrosion during the electrolysis, and the reaction rate was measured the highest in the kinetic analysis.