• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.9
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• pp.80-85
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• 2011

In this paper, complex discharge type ozonizer with a screw type electrode has been designed and manufactured for environmental improvement using low power and high efficency ozoniazer. The complex discharge type ozonizer is equipped with three electrodes{central electrode(CE), internal electrode(IE) and external electrode(EE)}. Ozone of the complex discharge type ozonizer is generated by superposition of silent discharge and surface discharge in discharge space as a screw type CE and IE are respectively applied to AC high voltage of inverse-polarity has $180[^{\circ}]$ phase difference, EE is common electrode. In this time, when oxygen has been used as supplied gas, the maximum values of ozone concentration, ozone generation and ozone yield were obtained as 8,334[ppm], 3,249[mg/h] and 65.3[g/kwh].

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1996.11a
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• pp.122-124
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• 1996

This paper describes a diagnosis of distribution cable splices by analysis of ultrasonic signals which are generated by partial discharge. A method of ultrasonic signal was used to detect internal defects in distribution cable splices. It is possible that analysis of ultrasonic signal predicts failure by partial discharge generated in distribution cable splices.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.12
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• pp.568-572
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• 2003

A longitudinal discharge heated copper vapor laser with internal diameter 28 mm and discharge length 1.3 m has been constructed and tested. At the discharging voltage 15.2 kV, pulse repetition rate 10 kHz, buffer gas pressure 40 mbar, and internal temperature of the laser plasma tube $1520^{\circ}C$, it delivers more than 30 W average laser outputs.

• Tuberculosis and Respiratory Diseases
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• v.57 no.1
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• pp.78-81
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• 2004

A 73-year-old man who had undergone a right pneumonectomy and open window thoracostomy due to tuberculous empyema, presented with purulent discharge from the previous operation site. The computed tomography of the chest showed diffuse pleural thickening and a low attenuated lesion, with air bubbles in a dependent portion of the right hemithorax. These air bubbles were revealed to be due to 7 pieces of retained surgical gauze by flexible bronchoscopy. The patient showed marked clinical improvement with diminished purulent discharge after removal of the foreign bodies.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.959-964
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• 2012

Internal pressure of vacuum interrupter (VI) is one of the most important parameters in VI operation and may increase due to the outgassing from the materials inside VI or gas permeation through metal flange or ceramic vessel. The increase of the pressure above a certain level leads to the failures of switching or insulation. Therefore, an effective pressure check of VI is essential and an analysis of partial discharge (PD) characteristics is an effective monitoring method to identify the degree of the internal pressure of VI. This paper introduces a research work on monitoring the internal pressure of VI by analyzing PDs which were measured using a capacitive PD coupler. The authors have developed cost effective capacitive coupler based on the ceramic material that has an excellent insulation properties and the main component of the capacitive coupler is made by SrTiO3. Detectable internal pressure range and distinguishability of the internal pressure of VI were investigated. From the PD tests results, the internal pressure range, from $10^{-2}$ torr to 500 torr, can be monitored by PD measurements using the capacitive coupler and PD inception voltage (PDIV) follows the Paschen's law. In addition, rise time of PD pulse at 13.2kV decreases with the increase of the internal pressure of VI.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.9
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• pp.1297-1301
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• 2013

This paper analyzes of PD occurrence position through an analysis of the arrival time difference between the GIS partial discharge signal. Because of GIS (Gas Insulated Switchgear) is a facility very important power equipment and as part of the equipment that make up the power system, the stabilization of the power industry, which accounted for 88.5% share of GIS substation in the form of a substation is an important equipment for power supply. In the situation where we are gradually expanding the need for preventive diagnosis in order to improve the efficiency of equipment management and failure prevention for Preventive diagnosis. In this paper as a method for extracting pre-defect of failure of GIS Apply the average value method of calculating the 5 times each using a pulse of the first time of the second pulse (${\Delta}t$) with an oscilloscope generation position PD(Partial Discharge). the results of GIS internal inspection, the partial discharge of the actual the position of the partial discharge was confirmed with an accuracy of about 82% of positions. Arrival time difference in the most effective manner if the partial discharge of GIS internal occurs by applying the averaging method and TOA(Time of arrival) method, the partial discharge occurs you through the measurement and analysis of PD signal occurs was confirmed in the experiment are presented and diagnostic methods location tracking.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.199-210
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• 1996

The measurements of velocities of internal flow in a scaled-up nozzle were made by laser Doppler velocimetry in order to clarify the effect of internal flow on the characteristics of fuel spray. The investigated length to diameter ratio(L/d) of the orifice were 1, 3, 4, 5 and 8, and inlet radius to diameter ratio(r0/d) were 0 and 0.5. Mean and fluctuating velocities and discharge coefficients were obtained at various Reynolds number ranging between 15,000 and 28,000, and L/d ranging between 1 and 8 in sharp and round inlet nozzle. The turbulent intensity and turbulent kinetic energy at exit in a sharp inlet nozzle were higher than that in a round inlet nozzle. For sharp inlet nozzle, fluctuating velocities near exit were decreased with increasing L/d.

• Journal of Energy Engineering
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• v.2 no.1
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• pp.38-44
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• 1993

Electromagnetic seawater thrusters may be classified into four general categories : internal duct dc, external field dc, internal peristaltic ac, and external peristaltic ac. Internal duct dc thrusters offer the advantages of low magnetic field leakage, simple construction, and potentially high reliability. The most efficient internal duct configuration consists of converging inlet nozzle and a straight discharge duct. Ideal efficiency calculations based on the one-dimensional Bernoulli equation show that thrusters should be designed with large cross-sectional areas and operate at low discharge velocities. In practice, this may be accomplished by using multiple thruster ducts. Conductivity enhancement, high magnetic fields, and long electrodes will also improve efficiency.

• Transactions on Electrical and Electronic Materials
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• v.10 no.5
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• pp.173-176
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• 2009

In the stator windings of a 6.6 kV rotating machine, internal discharges, slot discharges, and surface discharges are mainly caused by internal voids and insulation degradation. If a partial discharge(PD) occurs in an inner-part of the stator windings, it will cause electromagnetic pulses with wide frequency ranges. Discharge sparks and electromagnetic pulses generated from a discharge source, can be detected using various RF resonators like an EM sensor. In order to detect these types of electromagnetic sources, a planar patch sensor was designed and fabricated using a CST-MWS simulation, and PD signals from an artificially defected stator winding were also measured by the sensor proposed in this study. Furthermore, an HFCT was used as a reference sensor and compared with the proposed new planar patch sensor. In the results of the experiment, the planar patch sensor showed a similar performance to the HFCT sensor.

• Tuberculosis and Respiratory Diseases
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• v.83 no.2
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• pp.147-156
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• 2020

Background: Limited studies have been performed to assess readmission following hospitalization for community-acquired pneumonia (CAP) in an Asian population. We evaluated the rates, reasons, and risk factors for 30-day readmission following hospitalization for CAP in the general adult population of Korea. Methods: We performed a retrospective observational study of 1,021 patients with CAP hospitalized at Yeungnam University from March 2012 to February 2014. The primary end point was all-cause hospital readmission within 30 days following discharge after the initial hospitalization. Hospital readmission was classified as pneumonia-related or pneumonia-unrelated readmission. Results: During the study period, 862 patients who survived to hospital discharge were eligible for inclusion and among them 72 (8.4%) were rehospitalized within 30 days. In the multivariable analysis, pneumonia-related readmission was associated with para/hemiplegia, malignancy, pneumonia severity index class ≥4 and clinical instability ≥1 at hospital discharge. Comorbidities such as chronic lung disease and chronic kidney disease, treatment failure, and decompensation of comorbidities were associated with the pneumonia-unrelated 30-day readmission rate. Conclusion: Rehospitalizations within 30 days following discharge were frequent among patients with CAP. The risk factors for pneumonia-related and -unrelated readmission were different. Aspiration prevention, discharge at the optimal time, and close monitoring of comorbidities may reduce the frequency of readmission among patients with CAP.