• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.10
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• pp.65-72
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• 2000

In this paper, we propose an efficient technique to minimize the input offset of a dynamic latch comparator. We analyzed offset due to charge injection mismatching and unwanted positive feedback during sampling phase. The last one was only considered in the previous works. Based on the analysis, we proposed a modified dynamic latch with initialization switch. The proposed circuit was simulated using 0.65${\mu}m$ CMOS process parameter with 5v supply. The simulation results showed that the input offset is less than 5mV ant 200MHz sampling frequency and the input offset is improved about 80% compared with previous work in $5k{\Omega}$ input resistance.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.372-375
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• 2014

This experiment was undertaken to investigate proper conditions for protoplast isolation and genetic transformation of the white rot fungi, Polyporus brumalis. The protoplasts were formed from mycelia at a frequency of $1{\times}10^7/ml$ with 0.5% Usukizyme. The transformation vector (pHYgpt) was constructed using hygromycin resistance gene (hph) for the selectable maker. The yield was 100-160 transformants/${\mu}g$ DNA in a transformation mediated by 40% polyethylene glycol solution with aurintricarboxylic acid, heparin and supermidine. The genomic integration of the pHYgpt was confirmed by hph-specific PCR and the expected amplified band appeared only in the transformants. These results could be an efficient tool in gene engineering of the genus polyporus.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.220-228
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• 2012

In this paper, we explained the design technique about Ka-band active limiter for protecting the receiver of a millimeter wave seeker. To implement low flat leakage power, we proposed the control circuit of active limiter to control limiter voltage with PRF(Pulse Repetition Frequency) signal and input power. This active limiter consisted of the conventional 2 stage passive limiter, a feedback circuit with a directional coupler, detector, non-inverting amplifier and over-current protection resistance. As the test result of the fabricated Ka-band limiter, it had 1 GHz bandwidth, 3.5 dB insertion loss at the small input power and -7.5 dBm flat leakage at the 4 W RF input power, respectively.

• Journal of Advanced Navigation Technology
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• v.18 no.5
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• pp.483-489
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• 2014

Proposed electronic ballast circuit for harmonic reduction includes adding lossless snubber circuit to DC-DC converter. To get inverter for changing DC-AC, a lamp has been changed to equivalence resistance in the standard lamp voltage and current data, also inverter circuit has been interpreted by being changed to R, L, C equivalence circuit. Using converted equivalent circuit, the most suitable circuit constant which can satisfy the characteristics of fluorescent lamps has been decided on and finally designed. It could not only eliminate distortion waveform from pulsation frequency in inverter direct side current but also reduce considerably pulsation rate and switching loss by making input current of inverter discontinuous. The validity for the results of this study has been verified through the experiment to measure harmonic occurrence after applying a newly-manufactured product of electronic ballast to 40 W line tube style fluorescent lamps.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.7
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• pp.1093-1101
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• 2013

This paper demonstrates that 'Qi Energy Healing' effects on elevation of capabilities in regards with the autonomic nervous system which prevents from the stress. Nineteen participants were assigned into 'Qi Energy Healing' and the 'Ordinary Relaxation' condition. Participants were examined to see the difference of frequency domain analysis, heart rate tachogram, physical resistance through the heart rate variability. The 'Qi Energy Healing' is significantly more likely to influence on reducing and diminishing the stress. 'Qi Energy Healing' treatment showed clear distinction on 6 fact. Our findings established the link between effectiveness of 'Qi Energy Healing' and the autonomic nervous system.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.109-115
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• 2013

In this paper, we developed pressure mesuring system for powered wheelchair and tried to validate the usefulness of developed system by pressure measuring experiment with 3D motion analysis. This system consist of 64ch seat FSR(Force Sensitive Resistance) sensor unit, 30ch*2 armchair FSR sensor unit, analog and digital hardware board, 2ch rotary encoder unit and realtime signal processing & display S/W. And each data acquired from this system has sampling frequency of 12bit, 10Hz. Pressure measuring experiment for 10 persons who use wheelchair in real life was performed in the 3D vision analysis room. From the experiment, we obtained result that the center line of body inclined to outside direction during powered-wheelchair rotate any direction.

• Korean Journal of Clinical Laboratory Science
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• v.40 no.1
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• pp.48-54
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• 2008

Nine types of staphylococcal enterotoxin (SE) genes (sea~see, seg~sej), 3 types of virulence genes (eta, etb, tst), mecA and 16S rRNA as internal positive control were detected from 187 clinical MRSA (methicillin resistance Staphylococcus aureus) strains isolated from a variety hospitalized patients in Daegu and Gyeongsangbuk-do areas using the multiplex PCR. The frequency of the S. aureus strains harboring recently reported SE genes (seg~sej) were found to be very high (65.9%) and greater than that of the strains harboring classical SE (sea~see) genes (47.8%) as previously established. Taking into account that the newly described pairs form SE genes (i.e., sec+seg+sei, seg+sei) were many, in the other hand, single form SE genes (i.e., seg, seh, sei and sej) were rarely detected. The S. aureus with pairs form enterotoxigenic genes become more potentially toxigenic strains. Furthermore, this work indicated a systematic association between the seg and sei genes and their high incidence among the S, aureus strains, which suggests that these two SE's could be an important phylogenetic link among the staphylococcal enterotoxins.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.12
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• pp.1337-1344
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• 2007

It is shown that inverted ${\pi}$ feeder affects the gain improvement for the internal antenna of mobile phone. Generation of current on the inverted ${\pi}$ feeder, by the modification of conventional feeding structure for the PIFA and IFA, can apply T matching theory to the new feeder. Therefore, inverted ${\pi}$ feeder based on the T matching theory makes higher radiation resistance, and also increases the gain. To verify inverted ${\pi}$ feeding effect, feeder is applied to GSM/DCS dual band conventional PIFA, and measured return loss and patterns. By measurement, it's shown that this new feeding antenna has $0.23{\sim}0.84$ dB higher average gain for GSM band and $0.01{\sim}1.74$ dB higher average gain for DCS band than conventional fed PIFA without resonant frequency change.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.4
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• pp.8-15
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• 2000

In this paper, we realize the active PFC(Power Factor Correction) system of BF(Boost Forward) converter with PWM-PFM(Pulse Width Modulation-Pulse Frequency Modulation) control technique to control DC output voltage, to remove the noise like harmonics at output voltage, and to control the input current with sinusoidal wave synchronized by the source voltage.To achieve the desired load voltage and improved PFC, we first implement current shaping control at the inverting stage and make the converted output DC voltage with forward converter. After making the ratio of output voltage to current as 50V/1A and the duty ratio greater than 0.5. When input voltage is 30V and boost inductance is 1.1mH. we control the voltage changing rate according to the variation of load resistance using a PWM-PFM control technique. And finally we prove experimentally, we attenuated its harmonics and improved PF up to 0.96 using the current shaping technique.

• Journal of IKEEE
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• v.14 no.2
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• pp.82-89
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• 2010

In this paper, a buck-boost converter using three DTMOS(Dynamic Threshold Voltage MOSFET) switching devices is presented. The efficiency of the proposed converter is higher than that of conventional buck-boost converter. DTMOS with low on-resistance is designed to decrease conduction loss. The threshold voltage of DTMOS drops as the gate voltage increases, resulting in a much higher current handling capability than standard MOSFET. In order to improve the power efficiency at the high current level, the proposed converter is controlled with PWM(pulse width modulation) method. The converter has maximum output current 300mA, input voltage 3.3V, output voltage from 700mV to 12V, 1.2MHz oscillation frequency, and maximum efficiency 90%. Moreover, the LDO(low drop-out) is designed to increase the converting efficiency at the standby mode below 1mA.