• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.1
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• pp.31-38
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• 2002

We measured a 3-dimensional images of the light emitted from plasma display panel(PDP) by using newly proposed scanned point detecting system. In the panel without phosphor, as we scan from the rear glass to the front glass, the detected light intensity increases and the light intensity detected in the inside edge of the ITO electrodes shows the stronger intensity than others. The light intensity detected between the barrier ribs shows the largest value of brightness. Also, as the sustain voltage increases, the detected light intensity increases. In the panel with phosphor, the intensity of light detected at barrier rib shows the stronger light intensity than rear plate. Therefore, the phosphor of barrier rib is very important. From these results the 3-dimensional measurement is necessary to understand exactly the discharge phenomenon in the PDP cell.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.78-83
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• 2003

The aim of this study is to investigate the effect of hydrogen embrittlement od Zr-2.5Nb CANDU pressure tube. The test were performed at three hydrogen contents for transverse tensile and CCT specimens while the test temperatures were changed (RT to 300$^{\circ}C$). The specimens were directly machined from the tube retaining original curvature using electric discharge machine. Both the transverse tensile and the fracture toughness tests showed the hydrogen embrittlement clearly at RT but this phenomenon was disappeared while the test temperature arrived over 250$^{\circ}C$. From the fracture toughness test, it was found that fracture toughness dJ/da was increased up to 200$^{\circ}C$ and then decreased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.270-273
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• 2001

Electrical tree is studied widely by manufacture state of insulating material fare and blazing fire diagnosis system of use in phenomenon of part discharge that happen for main cause of dielectric breakdown of equipment for electric power. Use process that draw tree pattern here measuring above zero to study special quality of this electricity tree, real-time processing by image processing is proposed because reproduction of tree blazing fire process drops and pattern of tree is difficult correct quantification of tree growth by existent visual observation by involution. This research presents general process that need in image processing of tree blazing fire, and that remove various noises that happen in above zero by measuring electrical tree dividing background and complete view in measured above zero taking advantage of specially proposed complete view object abstraction techniques effectively and quantification of tree becomes easy naturally, can apply to dielectric breakdown estimate because can chase growth process of tree.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.85-90
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• 2006

This paper presents experimental results relating to the preliminary breakdown characteristics in $SF_6/CO_2$ gas mixtures under a highly non-uniform electric field. The impulse pre-breakdown developments are investigated by the measurements of corona current and light emission images. As a result, the preliminary breakdown development mechanisms for both the positive and negative polarities were fundamentally same. The first streamer corona was initiated at the tip of needle electrode, and the leaders developed with a stepwise propagation and bridged the test gap. The pause time of leader pulses in the positive polarity was significantly shorter than that in the negative polarity. Also, the time interval between the first streamer corona onset and breakdown in the negative polarity was much longer than that in the positive polarity. The discharge channel path in the positive polarity was zigzag, and the leader channel in the negative polarity was thicker and brighter than that in the positive polarity.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.55-56
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• 2006

In prevention and diagnostic system of GIS, pattern classification is focused on the detection of unnatural patterns in PD(Partial discharge) image data. Fractals have been used extensively to provide a description and to model mathematically many of the naturally occurring complex shapes, such as coastlines, mountain ranges, clouds, etc., and have also received increased attention in the field of image processing, for purposes of segmentation and recognition of regions and objects present in natural scenes. Among the numerous fractal features that could be defined and used for image data, fractal dimension and lacunarity have been found to be useful for recognition purposes Partial discharge(PD) occuring in GIS system is a very complex phenomenon, and more so are the shapes of the various 2-d patterns obtained during routine tests and measurements. It has been fairly well established that these pattern shapes and underlying defects causing PD have a 1:1 correspondence, and therefore methods to describe and qunatify these pattern shapes must be explored, before recognition systems based on them could be developed. The computed fractal features(fractal dimension and lacunarity) for standard library of PD data were analyzed and found to possess fairly reasonable pattern discriminating abilities. This new approach appears promising, and further research is essential before any long-term predictions can be made.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.12
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• pp.2335-2342
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• 2007

Laser stimulation has been widely studied and used in clinic. However, electrical response by laser stimulation on meridians has not been investigated. In this study, we compared electric potential of laser and acupuncture stimulation on meridians. We measured electric potential variation at acupoints(Samgan(LI3) and Hapgok(LI4)) on Large Intestine Meridian. In laser stimulation results, average peak electric potential is very low($7.53{\pm}3.44{\mu}V$) for before and after stimulation. However, acupuncture stimulation was performed in ground connection condition and resulted in huge variation of average peak electric potential($2.65{\pm}1.53mV$). That is, the intensity and pattern of electric potential were dependent on the ground connection condition and individual. Also, the electric potential pattern was very similar to the pattern of electric charge and discharge of capacitor. The acupuncture stimulation using a insulating needle resulted in lower average peak electric potential variation($0.25{\pm}0.16mV$) than that of acupuncture stimulation. It might present little electrical response of acupuncture stimulation using insulating needles. In point of electrical response, the laser stimulation was determined to be no acupuncture effect at meridian. Acupuncture stimulation seems to be most effective method to induce electrical response at meridians. The procedure and effect of acupuncture might be considered as energy consensus phenomenon by transportation of bio-ion charge between a practitioner and patient.

• Aerospace Engineering and Technology
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• v.7 no.2
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• pp.67-75
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• 2008

The electrostatic charging/discharging mechanism and its effects, and the system design considerations in the space plasma environment are studied in this paper. The electrostatic discharge (ESD) effects are carefully taken into account for a design of the satellite system at the early stage of the development. Generally, the electrical design requirements are specified to protect the satellite system from the ESD effects in the electromagnetic compatibility specifications. Those requirements are included the grounding, the bonding, the shielding, the conductive coating, the electric interfacing and so on. The space charging is caused by the increasing of the voltage difference between the each locations on the satellite surface. If the space charging is continued up to threshold, it may be occurred the system failure. This phenomenon is depended on the mission of system, electrical and mechanical configuration, system operation, and orbit condition. Therefore the related requirements are properly tailored and concentrated into the safety design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.545-549
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• 2006

W-EDM is generally used to manufacture punches and die plates from among press mold parts. Before W-EDM was used, however, punches and die plates manufactured via mechanical processing were used to manufacture products, with the die life of the mold expiring after 2,000,000~2,300,000 products have been manufactured. When the mold manufactured through W-EDM was used, however, its service life expired only after 700,000~800,000 products have been manufactured. Since this was attributed to the deformed layer formed after using W-EDM, the surfaces before and after W-EDM was used were scanned using SEM to verify the occurrence of such layer. This study sought to come up with a method of eliminating such phenomenon.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.270-273
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• 2001

Electrical tree is studied widely by manufacture state of insulating material fare and blazing fire diagnosis system of use in phenomenon of part discharge that happen for main cause of dielectric breakdown of equipment for electric power. Use process that draw tree pattern here measuring above zero to study special quality of this electricity tree, real-time processing by image processing is proposed because reproduction of tree blazing fire process drops and pattern of tree is difficult correct quantification of tree growth by existent visual observation by involution. This research presents general process that need in image processing of tree blazing fire, and that remove various noises that happen in above zero by measuring electrical tree dividing background and complete view in measured above zero taking advantage of specially proposed complete view object abstraction techniques effectively and quantification of tree becomes easy naturally, can apply to dielectric breakdown estimate because can chase growth process of tree.

• Economic and Environmental Geology
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• v.49 no.3
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• pp.243-248
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• 2016

This study was conducted to evaluate the applicability and efficiency of water supply using hydraulic ram pump. Study area is the Imgok-ri, Hwanam-myeon, Sanju-si, Kyeongsangbuk-do. There is an abandoned coal mine, where groundwater is discharged from its entrance with a flow rate of approximately $260m^3/day$. Hydraulic ram pump uses the waterhammer phenomenon and utilizes the power of falling water for pumping part of that water to a higher elevation than the water sources without electric power. To determine the efficiency of hydraulic ram pump, the flow rate was measured at three points according to the altitude difference (${\Delta}h=19m$ (point 1), 30 m (point 2), 40 m (point 3)). Flow rate measured at 1, 2, and 3 were about $8.6{\sim}10.8m^3/day$, $3.98{\sim}4.39m^3/day$, and $2.35{\sim}2.59m^3/day$, respectively. The current results suggested that, hydraulic ram pump could be applicable for the water supply system in mountain areas without external power supply.