• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.286-288
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• 1990

This paper reports the characteristics of sparkover discharge in flowing air ranging from 0[m/s] to 30 [m/s] under the needle-needle gap. Flowing air duct of this investigation is circular tube. The important results obtained form this study are as follows. 1. the ratio of sparkover voltage to the Reynolds number decreases with increasing the Reynolds number. 2. The duration time of sparkover(t) decreases with increasing the Reynolds number. 3. the empirical equation obtained form this experiment is [ %]${\frac{Vs}{Re}}$ = A + $B{\varepsilon}^{C.Re}$ where A = 10.2 b = 125 c = -4.66 ${\times}$ $10^{-5}$

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1724-1726
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• 2002

A novel ozonizer has been developed using a high-frequency surface discharge and a high purity alumina ceramic as its dielectric component. A thin ceramic layer, cylindrical in form, is adhered by a film-like induction electrode. An ac exciting voltage of frequency to 0.6 kHz from 1.0 kHz and $6{\sim}9kV$ peak-to-peak is applied between the electrodes to produce a stable high-frequency silent discharge for generation of ozone. A substantial reduction of the exciting voltage is also enabled by using a thin alumina ceramic layer. As a result, the ozonizer can easily produce ozone concentration($128g/m^2$ for oxygen) and power efficiency(360g/kWh for oxygen) without using a special enrichment means.

• The KSFM Journal of Fluid Machinery
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• v.8 no.6 s.33
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• pp.33-39
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• 2005

A thermal vapor compressor in which the subsonic/supersonic flow appears simultaneously, has been accurately designed through the CFD analysis for the various shape parameters such as the primary nozzle shape, converging duct shape, mixing tube diameter, and so on. The performance of the developed thermal vapor compressor has been experimentally verified to be installed in a Multi Effect Desalination(MED) plant as an important element. In this paper, the effects of each parameter are discussed on the basis of CFD results and the experimental results for various boundary conditions(motive pressure, suction pressure, and discharge pressure) are presented in compared with CFD results. The two results show a good agreement with each other within 2 % accuracy with regard to the entrainment ratio.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1556-1558
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• 1994

An air/quartz dielectric double barrier pulse discharge has been investigated to develop a novel si lent type ozone generator. It is found that there are very active pulsed coronas occurred in the airgap which are very useful for ozone generation. And, the corona onset voltage of the airgap of the air/quartz double barrier was enfluenced greatly by the airgap of the air/quartz dielectric double barrier, and depended greatly upon the airgap ranged of $0.0{\sim}3.0mm$ and by the quartz tube thickness ranged of $1.75{\sim}2.25mm$.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.355-359
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• 2006

ZnO varistor and GDT(gas discharge tube) have proven to be good protective devices because of their flexibility and high reliability. ZnO varistors are characterized by their excellent nonlinear properties. GDTs are used for applications in communication or signaling circuits because they have very low capacitance. Therefore, It is very important to understand the V-I characteristic of ZnO varistor and GDT for designing SPD to protect apparatus or personnel from high transient voltage. This paper gives experimental V-I characteristic data of ZnO varistor and GDT for protecting electronic equipments from surge up to maximum discharge current.

• Korean Journal of Optics and Photonics
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• v.1 no.2
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• pp.162-168
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• 1990

Two ZnSe loss plates were installed in the resonator of waveguide CO2 laser which consisted of Pyrex capillary tube in order to change the internal loss. By rotating the loss plates, the output variations with the internalloss was measured on various discharge conditions. The variations could be explained by the Rigrod theory. and the saturation power and the unsaturated gain coefficient were determined by fitting of the experimental results. It was found that the saturation power increased while the unsaturated gain coefficient reduced as the discharge current or the gas flow rate increased.reased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.1
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• pp.73-79
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• 2011

A portion of oil for lubrication of compressor flows together with refrigerant in the refrigeration system. If the oil discharge from a compressor is increased in the refrigeration system, not only pressure drop is increased in other components, such as evaporator and gas cooler, but also heat transfer coefficient in the heat exchangers is decreased. Oil discharge rate from a compressor may strongly depend on operating conditions of a compressor. In this study, one stage single rotary compressor is employed for measuring oil circulation ratio(OCR). Carbon dioxide and PAG oil are used as refrigerant and lubricant. Using a U-tube densimeter, mixture density is measured. Oil circulation ratio(OCR) can be estimated by measured mixture density. The results obtained indicate that the oil circulation ratio(OCR) is increased as the suction temperature or compressor operating frequency is increased. Oil circulation ratio(OCR) correlation of the compressor is also suggested.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.5
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• pp.164-169
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• 1983

A method to control the luminous colour of a gaseous discharge tube has been investigated by using the saw-tooth wave of which rise-time was controlled by an electronic circuit. The luminous colour of a Ne - Hg lamp was changed from red to blue continuously and vice versa, and it's luminous characteristics are as follows: (a) With D.C. potentials, it showed blue colour and the relative intensity of the colour is increased first and saturated at about 17 mA as the discharge current is increased. (b) When the rise-time of the saw-tooth wave is about 10 $\mu\textrm{s}$, the red colour which is caused by Ne - excitation is dominant, and when about 200 $\mu\textrm{s}$, only the blue colour which is caused by Hg - excitation is shown. (c) With saw-tooth pulse, the relative intensity of blue is increased similarly as that with D.C. potential as the current peak of each pulse is increased, while that of red is increasing continuously and it's intensity shows about twice than blue. (d) The spectrum of red colour contains Ne - excitation lines and Hg - blue lines, but the apparent luminous colour is red because Ne - red lines are more plenty than Hg-blue lines. The spectrum of blue colour presents only Hg-blre lines.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1628-1630
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• 2002

In this paper, we measured 3-dimensional temporal behavior of the light emitted from discharge cell of plasma display panel(PDP) as a function of the pressure using the scanned point detecting system. The detected light signal through the PM tube is sent on the oscilloscope and oscilloscope which is connected to PC with GPIB. The whole system is controlled by a PC. From the temporal behavior results, we could analyze the discharge behavior of panel with Ne-Xe(4%) mixing gas and 300torr, 400torr, 500torr pressure. The top view of panel shows that the discharge moves from inner edge of cathode electrode to outer cathode electrode forming arc type. At the 300torr, initial emission time is very fast. The side view of panel shows that the light is detected up to $150{\mu}m$ height of barrier rib. In the panel of 300torr, emission distribution is wider than the others.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.74-76
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• 2006

An external electrode fluorescent lamp (EEFL) has an advantage of a long lifetime in the ear1y stages of the study on plasma discharge, interest in the lamp continues. Researches on the operation of external electrode fluorescent lamps have focused mainly on its use of a type of high frequency (MHz). By performing high brightness using a square wave operation method with the low frequency below 100kHz, which is applied to a narrowed tube type lamp that has several mm of lamp diameter, EEFL presented the possibility of using it as a light source for back-lights. However, because EEFL generates plasma using wall charges, which considers the impedance characteristics of glass based on the structural principle in discharge, it can be significant1y affected by frequency. Thus, this study verified the change in the characteristics of electromagnetic fields according to the change in frequency through a Maxwell's electromagnetic field simulation and examined the relationship between the change in the EEFL frequency and brightness by measuring the optical characteristics. In addition, the characteristics of the transformation of energy orbits were verified by investigating the characteristics of the wavelength according to the change in frequency through the OES.