• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.236-243
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• 2009

Proton Engineering Frontier Project (PEFP) has supplied the metal ions to users by using an installed metal ion implanter of 120 keV. At present a feasibility study is being performed for a cobalt ion implantation. For a cobalt ion extraction we studied to sustain the high temperature($648^{\circ}C$) for metal ions vaporization from a cobalt chloride powder by using an alumina crucible in the ion source. The temperature condition of the crucible was satisfied with the plasma generation at the arc current of 120V and EHC power of 250W. The extracted beam current of $Co^+$ ions was dependent on the arc current in the plasma. The maximum beam current was $100{\mu}A$ at 0.18A of the arc current. The 3 peak currents of the extracted ions such as $Co^+$, $CoCl^+$ and $Cl^+$ were obtained by adjusting a mass analyzing magnet and the $Co^+$ ion beam peak current fraction as around 70% in the sum of the peak currents. The fluence of the implanted cobalt ions at the $10{\mu}A$ of the beam current and 90 minutes of the implantation time into an aluminum sample as measured around $1.74{\times}10^{17}#/cm^2$ by a quantitative analysis method of RBS (Rutherford Backscattering Spectrometry).

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.87-95
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• 2013

In this paper, 2.5 Gb/s burst-mode clock and data recovery(CDR) is presented. Digital frequency calibration scheme is adopted to eliminate mismatch between the input data rate and the output frequency of the gated voltage controlled oscillator(GVCO) in the clock recovery circuitry. A jitter rejection scheme is also used to reduce jitter caused by input data. The proposed burst-mode CDR is designed using 0.11 ${\mu}m$ CMOS technology. Post-layout simulations show that peak-to-peak jitter of the recovered data is 14 ps with 0.1 UI input referred jitter, and maximum tolerance of consecutive identical digit(CID) is 2976 bits without input data jitter. The active area occupies 0.125 $mm^2$ without loop filter and the total power consumption is 94.5 mW.

• Journal of Radiation Protection and Research
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• v.30 no.2
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• pp.69-75
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• 2005

Gas avalanche microdetectors, such as micro-strip gas chamber (MSGC), micro-gap chamber (MGC), micro-dot chamber (MDOT), etc., are operated under high voltage to induce large electron avalanche signal around micro-size anodes. Therefore, the anodes are highly exposed to electrical damage, for example, sparking because of the interaction between high electric field strength and charge multiplication around the anodes. Gas electron multiplier (GEM) is a charge preamplifying device in which charge multiplication can be confined, so that it makes that the charge multiplication region can be separate from the readout micro-anodes in 9as avalanche microdetectors possible. Primary electron collection efficiency is an important measure for the GEM performance. We have defined that the primary electron collection efficiency is the fractional number of electron trajectories reaching to the collection plane from the drift plane through the GEM holes. The electron trajectories were estimated based on 3-dimensional (3D) finite element method (FEM). In this paper, we present the primary electron collection efficiency with respect to various GEM operation parameters. This simulation work will be very useful for the better design of the GEM.

• Applied Chemistry for Engineering
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• v.16 no.3
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• pp.413-421
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• 2005

This study focused on the decomposition of toluene in a plasma-photocatalytic hybrid system. Hexagonally packed meso-structured Mn-titanosilicates (Mn-Ti-MCM-41), as the photocatalysts, have been prepared by the hydrothermal method. The physical properties of the photocatalysts were characterized using XRD, XPS, TEM, BET/ICP, and $NH_3$/Toluene-TPD. Experiments were carried out at the applied voltage of 9.0 kV and at room temperature of $20^{\circ}C$. In the plasma only system, the activity of the toluene decomposition was higher than that in the photocatalytic system. However, the amount of by-products, such as phenol, $C_2{\sim}C_4$ alkene, was also increased in the plasma only system. However, the by-products decreased remarkably in a plasma-photocatalytic hybrid system. When Mn5mol%-Ti-MCM-41 was used as a photocatalyst in a plasma-photocatalytic hybrid system, the $CO_2$ selectivity in products was increased dramatically compared to other catalysts. It was confirmed that a plasma-photocatalytic hybrid system was better for toluene decomposition compared to photocatalytic and plasma only systems.

• Journal of Broadcast Engineering
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• v.19 no.5
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• pp.726-735
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• 2014

In accordance with 4K UHD(Ultra High Definition) LCD television's higher resolution and data expansion, LCD TV had to face problems such as increasing numbers of cables and tangible skews problems among cables. The V-by-One HS is a new interface technology in the path between the image processing IC and timing control (TCON) board. The variable speed from 600 Mbps to 3.75 Gbps effectively meets the requirements of various different pixel rates. In this paper, we use the V-by-One HS interface to illustrate our proposed simulation method of frequency resonance mode and PCB design approach to model the effects of signal integrity for high speed video signal using an IBIS models.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5403-5408
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• 2012

In this paper, we introduce the multiple frequency bio-electrical impedance analysis method for body composition analysis. And then we implement the multiple frequency bio-electrical impedance analysis system. Overall system consists of: multiple frequency alternating current signal generator contained alternating current signal, phase signal detector, voltage signal detector, micro controller, in-out device(key-pad LCD), conductivity electrodes, system power. We explain the architecture of the system and required theory to implement the system. In order to investigate the clinical significance of the body composition data, compare to the data measured by the expert body composition analyzer which provide high reproduction and precision. Finally, experimental results which are the correlation between the measured data show the very high reproduction performance of the body composition analysis in the proposed system.

• Journal of the Korea Society of Computer and Information
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• v.6 no.2
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• pp.8-13
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• 2001

We demonstrate a pulsed CO$_2$laser with long pulse duration of millisecond order in the low pressure less than 30 Torr. A new power supply for our laser system switches the voltage of AC power line(60㎐) directly. The power supply doesn't need elements such as a rectified bridge, energy-storage capacitors. and a current-limiting resistor in the discharge circuit. In order to control the laser output power, the pulse repetition rate is adjusted up to 60㎐ and the firing angle of SCR gate is varied from 30˚ to 150˚. A ZCS(Zero Crossing Switch) circuit and a PIC one-chip microprocessor are used to control the gate signal of SCR precisely. The maximum laser output is 23W at the total pressure of 18 Torr, the pulse repetition rate of 60㎐, and SCR gate firing angle of 90˚. In addition, the obtained laser pulse width is approximately 3㎳(FWHM)

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.6
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• pp.575-583
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• 2003

In thesis we applied the short or open reflection type for IQ vector modulator The open or short type is operated even exception of other redundancy circuit. Generally IQ vector modulator uses MESFET in performing reflection open or short, then minus voltage which is having complex structure is required to operate MESFET via IQ signal. However BJT can be substituted for MESFET, BJT is improved characteristics like as cutoff frequency, electron mobility and so on. We used BJT in IQ vector modulator which is compatible with TTL level in I,Q digital signal, and attached AGC function. We got the result of operations within ${\pm}$ 1$^{\circ}$ phase and ${\pm}$ 0.6 dB amplitude Variation With full range of 20 dB and Variation of ${\pm}$ 6$^{\circ}$ Phase and ${\pm}$ 0.5 dB amplitude Versus full temperature range.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4984-4990
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• 2010

In this paper, a Step-down CMOS DC-DC Converter using low power switched capacitor method is designed in a 0.5 ${\mu}m$ technology for the integration of devices. Conventional DC-DC converter is used inductor that can store energy in a magnetic field but have low efficiency because power consumption is caused by magnetic flux. And there were problems with size, weight and price to integrate chip. In this paper, a proposed Inductorless step-down CMOS DC-DC converter of low power using SC method is designed in a 0.5um technology to solve these problems. Designed DC-DC converter have 96% power efficiency with 200kHz frequency by using cadence simulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.35-39
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• 2007

Home appliances, like air-conditionals, washers, refrigerators, etc., can cause voltage fluctuations and light flicker. A standardized flicker test has been established in Europe(IEC 61000-3-3, IEC 61000-3-11). The supply impedance of power supply system varies from plate to place, and for the flicker test in KOREA, the appliance manufacturers do need standardized impedance like the one indicated in IEC 61000-3-3 for 230[V]/50[Hz]. Without it, the same appliance will have different flicker level at different places. For appliance manufacturers, the flicker limit should be related to the reference impedance. However, the European flicker test is designed for 230[V]/50[Hz] power and needs to be modified for a 1P2W(220[V]/60[Hz]) supply system in KOREA. In this paper, the reference impedance for KOREA(220[V]/60[Hz]) systems is proposed. The measured result provided in this paper was served as a proposal for establishing KOREA reference impedance for 220[V]/60[Hz] and has been published in IEC 60725.