• Journal of the korean Society of Automotive Engineers
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• v.13 no.6
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• pp.82-89
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• 1991

In order to investigate the characteristics of flow around the intake around the intake valve exit, discharge coefficient and the velocity near the valve exit in steady state were measured using X-type hot-wire. Valve and valve seat insert used in experiment were constructed as the same shape of production engine and the flow characteristics at various flow rates and valve lifts were investigated. From the results of discharge coefficient measurements, it is observed that there exists a similarity between the flow characteristics around the production engine valve and the typical poppet valve. Measurement of the velocity at the valve exit shows that the normalized radial velocity between the primary direction of flow and the valve angle is large, but the difference becomes smaller as the flow rate increases.

• Journal of Korea Water Resources Association
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• v.37 no.8
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• pp.623-630
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• 2004

In this paper, the hydraulic model tests are conducted for the hydraulic characteristics at channel junctions. The experiments are examined through the variation of approaching angle, discharge in the upstream main channel and the discharge ratio between the main channel and the tributary. The experiments are conducted in the channel model having the length of 450cm, the widths of 40cm and 32cm. Four water tanks and pumps are installed in the experimental channel. The length of stagnation zone is increased by Increasing of approaching angle and the discharge in the upstream channel. The length of stagnation increase with the discharge ratio between the main channel and the tributary. However, the variation of the stagnation zone near the channel junctions is little at the same approaching angles and the discharge ratioes between the main channel and tributary. However, the variation of the stagnation zone near the channel junctions is little at the same approaching angles and the discharge ratioes between the main channel and tributary. Accelerating zone of the velocity is occurred in the middle of the channel in the small approaching angle. However, the influence zone of the accelerating velocity is increased by increasing the approaching angle.

• 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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2184-2188
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• 2007

We developed a novel method of partial discharge(PD) location based on the fact that the waveform of PD signal propagate along the GIB (Gas Insulated Bus) is composed of several modes of electromagnetic wave with different group velocities and cut-off frequencies. From the PD waveform, measured at a broadband PD sensor attached on the GIB, we could derive arrival time and frequency components of different modes using the short term Fourier transform or etc. After the group velocities of different modes are calculated, the location of the PD source could be estimated. To show the effectiveness of this new locating method in a real on site application, we used this method to locate the position of a PD source at a 76 m long 345 kV GIB substation. The estimated location of the PD source using the method proposed above was in good agreement with the actual location found from the inspection result of internal component in the GIB with 2.4% of the estimation error.

• Journal of the Korean Society of Safety
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• v.27 no.6
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• pp.166-171
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• 2012

This study aims to analyze the hydrological characteristics of downstream areas by the dam discharge of Soyanggang dam by using HEC-RAS Model. As a result of analyzing the data of dam discharge divided into hydropeaking discharge and total discharge, it as found that the maximum hydro-peaking discharge and the maximum total discharge have been 254.4 CMS and 1567.7 CMS respectively for the past 11 years. When the hydro-peaking discharge was applied to HEC-RAS Model, there occurred some sections where the water level rapidly changed, but the velocity of moving water was quite stable in the range between 0.23 m/sec and 1.16m/sec. Besides, when the total discharge was applied to this model, the submersible bridge along the dam downstream was flooded, and in some sections, the water level increased over the flood plain. Accordingly, this study judged that it is required to necessarily consider all the influence made by an increase of Soyanggang Dam's discharge when waterfronts are installed or used at dam downstream areas.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.346-351
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• 2000

The study was carried out to investigate the characteristics of vertical velocity distribution measured by current meter at Kangkyung station in Keum river during the period of 1995 to 1997. It suggests the quadratic parabola equation to estimate the vertical velocity profile only from the measurement data of surface velocity. The equation was found to be statistically very stable and showed high significance to express the surface velocity and bottom velocity. The vertical velocity profile was determined by the relationships to the surface velocity, and a coefficient of the quadratic parabola equation. The vertical velocity profile can be applied to calculating the mean velocity and discharge, and to and to analyse the dispersion of pollutant materials in the streamflow.

• Journal of Environmental Science International
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• v.4 no.2
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• pp.169-180
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• 1995

This Daper presents effective simulation of the dispersion of thermal discharge which can be relesed at Boryong power plant. Applied numerical models are finite difference method for hydrodynamic analysis and Masch-model comprised of conditions for ambient current velocity. Application of these models is done in Cheonsu Bay Summing up the results of this study are as follows; 1. It is found that the result for measurements of temperature appears high at southwardly Songdo on flood. The reason is that tidal currents which flowed north direction were accompanied with southwardly dispersed thermal discharge. A minute Particle of thermal Plume has a tendency to dispels inward Deacheon Bay. 2. According to the results of numerical experiment, maximum distance for thermal discharge dispersion appeared 10.8 km at lower part and 8.6 km at upper part with power plant outlet as starting point. 3. Comparative the numerical simulation and Airbone Multispectral Scanner indicated that thermal discharge should be verified separative phenomena. The simulated results were compared with field data set showing good agreement. It is concluded that these model can be simulated well.

• Child Health Nursing Research
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• v.10 no.1
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• pp.5-13
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• 2004

Purpose: The aim of this study was to analyze the correlation of gestational age and birth weight with weight gain of very low birth weight infants(VLBWI) during their hospital stay. Method: This is a 5 year retrospective study of which data were collected through review of medical records. Subjects were 124 VLBW infants with a birth weight more than 1000g and less than 1500g who received neonatal intensive care at the university hospital between January 1, 1997 to December 31, 2001. Result: After calculating the z scores of birth weights and discharge weights, z scores of discharge weight and birth weight were compared with the median weight of a fetus of comparable gestational age based on an intrauterine growth reference. There was a significant difference between z scores of birth weight and discharge weight(t=11.60, df=122, p=0.000). Regardless of intensive care during the prolonged hospital stay, VLBW infants showed slow growth rate compared with the median weight of a fetus of comparable gestational age. Conclusion: VLBW infants developed a poor velocity of weight gain during the prolonged hospital stay after birth. The development worsened during the period of physiological weight loss and regain, and they did not reach to comparable growth rate of normal fetus even at the time of discharge. This poor growth velocity of VLBW infants influence negatively for their future growth. Therefore nureses who work at the neonatal intensive care unit must develop an effective nursing intervention protocol to promote the velocity of weight gain and to conduct the parental educational sessions to emphasize the importance of weight gain for VLBW infants at home.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.74-80
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• 2003

Ionic wind is produced by a corona discharge when a DC high voltage is applied across the point-to-plane gap geometry. The corona discharge phenomena have been investigated in several beneficial application fields such as electrostatic cooling, ozone generation, electrostatic precipitation and electrostatic spraying. Recently ionic wind might be used in aerodynamic, for example, heat transfer, airflow modification, and etc. In this work, in order to analyze the control behavior of the velocity and amount of ionic wind produced by the positive DC corona discharges. The ionic wind velocity was measured as a function of the applied voltage, diameter of the punched hole on plate electrode and separation between the point-to-plate electrodes. As a results, the airflow is generated from the tip of needle to the plate electrode in the needle-to-punched-plate electrode systems. The ionic wind velocity is linearly increased with an increase in applied voltage and ranges from 1 to 3 m/sec at the locations of 100-200 mm from the punched-plate.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.5
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• pp.75-86
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• 2005

Recently since urbanization has brought about a dried stream and a worse water quality, Anyang city discharged the third treated sewage into the upper stream of Anyancheon and Hakuicheon. As the result, Hakuicheon had the water level and velocity enough for a living thing in the water to live in but water quality was worse than it had been. Therefore in case of meeting the water level and velocity of the second grade water-quality which living things in the water can live in, the discharge and water quality to secure in-stream flow must be at least 0.350 $m^3/s$ and $BOD_5\;3.2 mg/{\iota}$ respectively. In Anyancheon the water level was increased a little higher than it had been but the velocity was almost unchanged in comparison with it before. On the other hand the water quality was a little better than it had been. Therefore in case of meeting the water level and velocity of the third grade water-quality that people can do water-friendly activity, the discharge and water quality to secure in-stream flow must be at least 0.688 $m^3/s$ and $BOD_5\;4.8 mg/{\iota}$ respectively. The water-quality prediction on the suggested eight scenarios was simulated in all satisfying the third grade water-quality.