• The Journal of the Korean Society for Microbiology
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• v.22 no.1
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• pp.95-99
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• 1987

When tetracycline resistancy were cured by ethidium bromide treatment, some of the cured strains lost the tetracycline resistance plasmid while other strains kept the plasmids. Both strains of lost and remained plasmids were digested with restriction endonuclease Hind III and these cleaved plasmids were compared with that of parent strains, two plasmid remained strains showed same cleavage patterns between parent and cured strains, however, one plasmid lost strain showed dissimilarity with parent strain, but in the other one strain, among 4 plasmid lost colonies, 2 showed same but other 2 showed different patterns compared to parent strain. Tetracycline was transfered by conjugation in on set(Staphylococcus aureus donor versus Staphylococcus epidermidis, recipient) with relative high frequency but the other 2 sets showed a low degree of frequency and the other 2 sets exhibited no transfer.

• Journal of Sensor Science and Technology
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• v.21 no.3
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• pp.172-179
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• 2012

This paper presents the design and analysis of a vibration-driven electromagnetic energy harvester that uses a multi-pole magnet. The physical backgrounds of the vibration electromagnetic energy harvester are reported, and an ANSYS finite element analysis simulation has been used to determine the different alignments of the magnetic pole array with their flux lines and density. The basic working principles for a single and multi-pole magnet are illustrated and the proposed harvester has been presented in a schematic diagram. Mechanical parameters such as input frequency, maximum displacement, number of coil turns, and load resistance have been analyzed to obtain an optimized output power for the harvester through theoretical study. The paper reports a maximum of 1.005 mW of power with a load resistance of $1.9k{\Omega}$ for 5 magnets with 450 coil turns.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.12
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• pp.1218-1229
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• 1991

The time optimal position control design can be repeatedly taken from the initial state of a dynamic system to a desired one as fast as possible in the industrial drives. In this case, an induction machine parameters will vary due to temperature, frequency, and saturation effects. In particular, the rotor resistance changes critically with temperature and frequency. These changes affect the command values of the stator current components and slip speed. There is a mismatch between the commanded variables and actual ones of the induction motor drive, and this situation leads to coupling of the vector controller from the plant, i.e. the induction motor . Consequences of such a coupling include the initiation of oscillations of the rotor flux and unsuitable switching of electromagnetic torque for the induction motor servo drive. Therefore, this paper describes a rotor resistance parameter compensating method for the induction motor, And the validity of the proposed design method is confirmed by simulation studies and experiment results.

• Journal of Sensor Science and Technology
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• v.20 no.1
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• pp.25-29
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• 2011

This paper describes the design and analyses of vibration driven electromagnetic energy harvester with high power generation which is suitable for supplying power generator from human body motion. The proposed harvester consists of magnet, coil, and SM (Soft magnetic Material). In order to generate more induced voltage, the SM to concentrate flux lines from end of magnetic poles was arranged into insert moving magnet. Each model was designed and analyzed by using ANSYS software to simulation. The maximum power is generated when load resistance of $1303\;{\Omega}$ is equal to coil resistance. The generated maximum power of for harvesters with SM is $677.85\;{\mu}W$ and 5.46 times higher than without SM at 6 Hz vibration frequency.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.261-263
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• 1996

The study on the development of one-channel gas sensor using the quartz crystal analyzer were attempted. The adsorption and desorption behavior of organic gases were investigated using the resonant frequency and resistance method of quartz crystal. The sensitive materials were deposited on the quartz crystal analyzer(QCA) by using Langmuir-Blodgett method. To investigate the response characteristics of organic vapours and response mechanism, resonant frequency-resonant resistance (F-R) diagram was used. In our experimental results, the response mechanism between sensitive LB film and organic vapours was obtained using F-R diagram. And the position of each organic vapour were different as to the kind and injection amount. Thus F-R diagram can be applied to one-channel gas sensor using the QCA and useful to analyze the response mechanism between organic vspours and sensitive LB films.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.5
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• pp.409-415
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• 2007

For satisfying a recommended value of the quality factor which is one of the important elements in a filter design, a new design method of smoothing filter using an internal parameter of a homopolar generator is proposed. The method increases the efficiency and minimizes the size of the smoothing filter by removing the damping resistor. By considering the resonant frequency as well as the quality factor, the new method can improve the stability of the system which has high boosting converters with negative resistance characteristics.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.3
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• pp.139-144
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• 2003

We report the results of extensive mixed mode simulations and theoretical analysis to quantify the contribution of the edge direct tunneling (EDT) current on the total gate leakage current of 80nm NMOSFET with SiO2 gate dielectric. It is shown that EDT has a profound impact on basic analog circuit building blocks such as sample-hold (S/H) circuit and the current mirror circuit. A transistor design methodology with zero gate-source/drain overlap is proposed to mitigate the EDT effect. This results in lower voltage droop in S/H application and better current matching in current mirror application. It is demonstrated that decreasing the overlap length also improves the basic analog circuit performance metrics of the transistor. The transistor with zero gate-source/drain overlap, results in better transconductance, input resistance, output resistance, intrinsic gain and unity gain transition frequency.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.222-225
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• 1999

This paper presents the surges response of the grounding systems using frequency domain electromagnetic field analysis software package. The frequency and time domain performance of a building grounding systems subjected to a lighting strike is described and discussed. The computed scalar potentials is presented graphically as a function of spatial coordinates. A double exponential lighting surge current is injected at one corner or the building grounding systems. Time-variant response of rod, mesh and kit grounding systems under impulse currents have been obtained. This paper deals with the results of studies on the time variation of ground resistance in three grounding systems.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.103-105
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• 1993

This paper proposed a new direct vector control scheme using high frequency current injection. This scheme has some attractive features such as using no flux sensor or speed sensor, robustness of parameter variation, capability of accurate vector control at very low speed. Compared to other direct vector control scheme, this scheme doesn't depends on phase delay and difference of magnitude of estimated flux, rotor resistance and all inductances except stator resistance. These features are proved by computer simulation and experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.6
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• pp.49-56
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• 2011

Grounding system insures a reference potential point for electric devices and also provides a low impedance path for fault currents or transient currents in the earth. The ground impedance as function of frequency is necessary for determining its performance since fault currents could contain a wide range of frequencies. In this paper, the grounding resistance, grounding impedance and transient grounding impedance are measured by using 3-point fall-of-potential method in order to analyse grounding characteristics of the copper and concrete rod grounding electrodes. An equivalent transfer function model of the ground impedance and transient grounding impedance are identified from the measured values by using ARMA method and evaluated by comparing the conventional grounding impedance.