• Journal of Korean Port Research
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• v.12 no.1
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• pp.131-143
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• 1998

This paper presents derivation of stage-discharge curve for Yangsan river. To derivate of stage-discharge lationship is one of the essential research areas in the water resource field. It provides reliable data a long term planning and hydrologic quantity on water resource development by quantitative analysis. The rating curve derivated through 15 discharge-observation on Yangsan river basin in 1997 has been estimated Q=1283.0262-1553.3158H+477.2702H2. According to the rating curve, the highest water level 2.6m, the limited water-level should be bound to the maximum of 2.6m. Before this research, stage-discharge curve of Yangsan river has not been developed, and only 15 discharge observation(hydrometry) has been carried out though this research. Therefore it seems necessary to collect observation data through a long term process to obtain a reliable rating curve equation.

• Journal of Environmental Science International
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• v.23 no.4
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• pp.561-569
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• 2014

The water resources system of Jeju-do Island entirely depends on groundwater. This study is making a precision observation of baseflow, surface water, water shortage that might be vulnerable to climate change and drought in future. The field observation of baseflow discharges in Akgeuncheon stream has regularly been made with ADCP and ADC and Flowmate every two weeks for twenty-two (22) months (July 8, 2011 to April 27, 2013). This paper represent the results of calculating discharge of a number of hydraulic structures (broad-crested weirs) with comparing and has been calculated more accurate discharges with suitability of different observation methods. The average discharge has been observed 0.851 $m^3/s$, whereas the average ADC and Flowmate is 0.709 $m^3/s$. Meanwhile, stream discharge has been calculated 0.709 $m^3/s$ through the broad-crested weir equation. The discharge has calculated with the weir equation greatly changed according to even a small change in the water level. However, it showed a similar trend to one of the observed discharge. Although, in past there were generating errors caused by observers' strides, vertical and horizontal flow velocity distribution when the average flow velocity had been measured, non-prismatic flow, turbulent flow and others in ADC. This study comes up with the weir equation is more suitable for the characteristics of Jeju-do could be presented through an observations of baseflow discharge.

• Journal of Applied Reliability
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• v.13 no.2
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• pp.129-140
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• 2013

As a fundamental experimental study for reliability improvement of lithium ion secondary battery, degradation mechanism was investigated by microscopic observation and acoustic emission monitoring. Microstructural observation of the decomposed battery after cycle test revealed mechanical and chemical damages such as interface delamination, microcrack of the electrodes, and solid electrolyte interphase (SEI). Acoustic emission (AE) signal was detected during charge and discharge of lithium ion battery to investigate relationships among cumulative count, discharge capacity, and microdamages. With increasing number of cycle, discharge capacity was decreased and AE cumulative count was observed to increase. Observed damages were attributed to sources of the detected AE signals.

• Journal of Environmental Science International
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• v.26 no.12
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• pp.1321-1331
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• 2017

This study reviewed the applicability of the existing flood discharge calculation method on Jeju Island Han Stream and compared this method with observation results by improving the mediating variables for the Han Stream. The results were as follows. First, when the rain-discharge status of the Han Stream was analyzed using the flood discharge calculation method of the existing design (2012), the result was smaller than the observed flood discharge and the flood hydrograph differed. The result of the flood discharge calculation corrected for the curve number based on the terrain gradient showed an improvement of 1.47 - 6.47% from the existing flood discharge, and flood discharge was improved by 4.39 - 16.67% after applying the new reached time. In addition, the sub-basin was set separately to calculate the flood discharge, which yielded an improvement of 9.92 - 32.96% from the existing method. In particular, the steepness and rainfall-discharge characteristics of Han Stream were considered in the reaching time, and the sub-basin was separated to calculate the flood discharge, which resulted in an error rate of -8.77 to 8.71%, showing a large improvement of 7.31 - 28.79% from the existing method. The flood hydrograph also showed a similar tendency.

• Proceedings of the Korean Vacuum Society Conference
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• 1997.07a
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• pp.173-176
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• 1997

A numerical analysis of the micro-discharge in an AC pplasma dispplay cell has been made using time-deppendent, 2-dimensional multi-fluid equations to understand the discharge pphysics of He-Xe discharge. The time deppendent distribution of the electron tempperature, densities of electrons, various ions and excited sppecies, and the effects fo the wall charge accumulated on the dielectric surface are obtained and comppared with the results of direct observation of time deppendent behavior of VUV and visible sppectra from single discharge cell observed using a gated, image intensified CCD to elucidate the discharge physics.

• Journal of the Semiconductor & Display Technology
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• v.15 no.2
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• pp.26-31
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• 2016

The Townsend to glow discharge mode transition was investigated in the dielectric barrier discharge (DBD) helium plasma source which was powered by 20 kHz / $4.5 kV_{rms}$ high voltage at atmospheric pressure. The spatial profile of the electric field strength at each modes was measured by using the intensity ratio method of two helium emission lines (667.8 nm ($3^1D{\rightarrow}2^1P$) and 728.1 nm ($3^1S{\rightarrow}2^1P$)) and the Stark effect. ICCD images were analyzed with consideration for the electric field property. The Townsend discharge (TD) mode at the initial stage of breakdown has the light emission region located in the vicinity of the anode. The electric field of the light emitting region is close to the applied field in the system. Immediately, the light emitting region moves to the cathode and the discharge transits to the glow discharge (GD) mode. This mode transition can be understood with the ionization wave propagation. The electric field of the emitting region of GD near cathode is higher than that of TD near anode because of the cathode fall formation. This observation may apply to designing a DBD process system and to analysis of the process treatment results.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.320-323
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• 2007

The vacuum sealing method is adopted to minimize the residual impurity gas by enhancing a base vacuum level, and the resultant changes in the reset, address, and sustain discharge characteristics, such as a firing voltage, IR emission, and ICCD image, were examined in comparison with the conventional sealing method in the 42-in. AC-PDP. In the PDP cells fabricated by the vacuum sealing method, the ICCD observation illustrates that the discharge is initiated and extinguished very fast and its IR emission intensity is high.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.2
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• pp.15-30
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• 2008

Studies were carried out the phenomenal observation on the effect of corona treated hotmelt laminating film in process of manufacture by 2 kinds of experiments. These are as follow: 1) In order to verify the treatment reducing value of dynes and dynes durability with the lapse of time, it was checked dynes of a pair of 4 bar discharge electrode with 9 one for 144 hr., and it show results that 9 bar discharge electrode has higher initial dynes as well as keep up 48 dynes durability long than 4 one. 2) Drawn an inference from 3 actions -Chemical-Physical-Mechanical, on laminating film in terms of SEM's observation that are the adhesive status in boundary of corona treated base film, extrusion coating hotmelt layer, and configuration of hotmelt surface after corona treated. In tandem system, EVA layers adhesion keep its stability without corona discharge treatment.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.05a
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• pp.67-75
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• 1997

To establish testing method for ignition energy of explosive powders caused by electrostatic discharge, one testing method using a very small quantity of tested powders ( Frima ) was proposed, and the influence of discharge - limiting resistance connected in series into a capacitive discharge circuit on ignition energies of explosive powders was investigated using, as tested powders. As a result the minimum ignition energy was 9 mJ when discharge-limiting resistance was 300 k$\Omega$. The reason for the dependence of ignition energy on discharge-limiting resistance was thought to the difference in the type of electrostatic discharge, such as arc or glow discharge, from the observation of discharging wave forms.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.13-18
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• 1998

After Computer-based PD measurement was referred in the 1970's, the new technology and a number of digital system have been studied. And the selection of PD patterns, extraction of relevant information for PD recognition are discussed because the number of pulse as a function of discharge magnitude and discharge pulse as a function of the power frequency cycl4e offer the information of the aging insulation. This paper investigates the discharge phase($\phi$) and magnitude(q), as well as the number of discharge(n) with regard to discharge signals generated in power cable. Therefore, according to properties analysis on the distribution of $\phi$ , q and n, it is able to apply in the aging analysis of power cable which visual observation is impossible and distribution change of discharge signals offers much information for risk degree on aging progress of insulation materials.