• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.485-488
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• 2001

This paper provides the result of analysis of the structure and I-V characteristics of D.C. 1500 V surge arresters which were installed in railway line currently. As Porcelain housed surge arresters have unstable elements such as exploding and dispersion, so it is thought that the system is protected more stably with replacement of polymer housing. The adoption of gap mitigates the voltage stress which is degradation factor of surge arresters and the research is needed to enhance the life characteristic in additive and manufacturing process. Therefore, it is thought that the research should be continued to develop homemade the surge arresters for D.C. railway line as well as transmission line.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.52-55
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• 1997

This paper discusses an automatic visual-servoing system, in which a laser and a CCD camera are used for imaging the pattern of joint groove. The algorithm used here is simple and robust to find out the gap width and gap center. As a consequence, the speed of algorithm is very fast and optimized. A feature of this system is that it processes only by summing the vertical line and horizontal line of screen without any image preprocessing in order to get the energy information of lines alternatively. It is practical and useful for the system requiring a fast process time of vision.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.252-255
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• 2009

The roll gap set-up in the finishing mill is one of the most important technologies in the hot plate rolling process. As the target thickness can be obtained by the correct set-up of the roll gap, improving the roll gap set-up technology is very critical for plate thickness accuracy. The main cause of thickness variation in hot plate mills is the non-uniform temperature distribution along the length of the slab. The objective of this study is to adjust the roll gap set-up for the thickness accuracy of plate in hot rolling process considering top-end temperature drop. Therefore this study has concentrated on determining the correct amounts of roll gap to compensate thickness variation due to top-end temperature drop. The off-line simulation of compensated roil gap significantly decreases top-end thickness variation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1071-1077
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• 2009

Because several winds cause the a fault of transmission supply, KEPCO trys to protect the the trouble and supply the power stably. Kepco find out the weak mountains by winds and strengthen the power equipment annually. Power quality is the competition power in the international world and satisfy the customer using th power Therefore this paper deals with the fault relation between winds and transmission line.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.150-155
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• 2013

A high voltage and nanosecond Blumlein pulse generator has been developed to produce an output pulse whose voltage level is greater than 250 kV and pulse duration 5 ns. The generator consists of various components such as a charging circuit, a pulse transformer, and a spark gap switch. As a heart of the generator, a Blumlein pulse forming line has been constructed in the cylindrical form using three cylindrical aluminum electrodes that are placed concentrically. Unlike the ideal Blumlein line, the output pulse of an actual Blumlein line may be affected by stray inductances and capacitances of switching and charging components, thereby degrading the performance of the generator. In this paper, PSPICE simulations have been performed to examine effects of stray inductances and capacitances on waveforms of output pulses. Simulation results show that the pulse waveform is significantly distorted mainly by the stray inductance of the spark gap switch.

• Korean Journal of Optics and Photonics
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• v.7 no.1
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• pp.28-36
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• 1996

We have constructed and studied a laser system which consists of a multiplex spark gap with 8 couples of spark gaps and a multiple parallel plate capacitor type Blumlein transmission line circuit. In this laser system, the length of the laser tube, the length of the multiplex spark gap and the total thickness of the transmission line circuit are chosen to be 520 mm. The experimental results show that one couple of spark gaps cannot give a uniform and complete lasing through the whole laser tube. All the more, a multiplex spark gap could not perform completely and synchronously. However, a multiplex spark gap in found to contribute to the increase of laser output power and the laser has performed the best when the location is three quarters of the laser tube length.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.527-531
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• 1998

This study introduce to the fuzzy membership filter to cancel a high frequency noise of welding current. And ART2 which has the competitive learning network classifiers the signal patterns for the filtered welding signal. A welding current possesses a specific pattern according to the existence or the size of a welding gap. These specific patterns result in different classification in comparison with an occasion for no welding gap. The patterns In each case of 1mm, 2mm, 3mm, and no welding gap are identified by the artificial neural network. These procedure is an off-line execution. In on-line execution, the identification model of neural network for the classified pattern is located on ahead of the welding plant. And when the welding current patterns pass through the neural network in the direction of feedforward. it is possible to recognize the existence or the size of a welding gap.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.952-954
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• 2002

The effort for measuring the rotor vibration caused by the short of rotor winding or air-gap eccentricity has been carried on. This paper introduces on-line vibration monitoring technologies using search coils to measure flux for synchronous generators. A 3,300/6,600 (V), 150 [kW] synchronous generator is built, and search coils are designed and inserted in the wedges. Furthermore, air-gap eccentricity is analyzed by finite element method and compared with experiment tests. Induced voltages caused by different air-gap eccentricity on the search coils are compared as well.

• Journal of Microbiology and Biotechnology
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• v.21 no.5
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• pp.477-482
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• 2011

There are accumulating evidences suggesting that connexin (Cx), a gap junction channel-forming protein, acts as a growth suppressor in various cancer cells, and this effect is attributeed to the gap junction-mediated intercellular communication (GJIC). In order to characterize the relationship between the growth-arresting activity of Cx26 and its cytoplasmic localizations after expression, we linked a nuclear export signal (NES) sequence to Cx26 cDNA before transfecting into a rat breast cancer cell line. A confocal fluorescent microscopic observation revealed that the insertion of NES minimized the nuclear expression of Cx26, and increased its cytoplasmic expression, including plasma membrane junctions. Total cell counting and BrdUrd-labeling experiments showed that the growth of the breast cancer cells was inhibited by 74% upon transfection of Cx26-NES, whereas only 9% inhibition was observed with only Cx26 cDNA.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.2 s.25
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• pp.136-142
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• 2006

A damped sinusoidal electromagnetic pulse generator was designed, fabricated and tested. The pulse generator consisted of an oscillator(a spark gap switch and an initially charged low impedance line) and a high impedance antenna. This generator was capable of producing damped sinusoidal pulses at closure of the spark gap switch. A Marx generator was employed to supply the Pulse generator with high voltage pulses. While the pulse generator was provided with the high voltage pulses of 200kV from the Marx generator, its output power was maximized by controlling the pressure of the gas contained in the spark gap switch. The output power of the damped sinusoidal electromagnetic pulse oscillator was 1.3GW and the amplitude of electric field radiated from the pulse generator was 4kV/m at the range of 25m.