• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.570-571
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• 2005

In this paper, we introduced a LIF measurement method and summarized the theoretical side. When an altered wavelength of laser and electric power, lamp applied electric power, we measured the relative density of the metastable state in mercury after observing a laser induced fluorescence signal of 404.8nm and 546.2nm, and confirmed the horizontal distribution of plasma density in the discharge lamp. The results confirmed the resonance phenomenon regarding the energy level of atoms along a wavelength change, and also confirmed that the largest fluorescent signal in 436nm, and that the density of atoms in 546.2nm ($6^3S_1\rightarrow6^3P_2$) were larger than 404.8nm ($6^3S_1\rightarrow6^3P_1$). According to the increase of lamp applied electric power, plasma density increased, too. When increased with laser electric power, the L1F signal reached a saturation state in more than 2.6mJ. When partial plasma density distribution along a horizontal axis was measured using the laser induced fluorescence method, the density decreased by recombination away from the center.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.2
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• pp.85-91
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• 2015

A gasoline engine automobile uses high voltage generation of the ignition coil, igniting and burning mixed fuel in the combustion chamber, which drives the engine. When the electronic control unit intermits a current supplied to the power transistor, counter electromotive force with a low voltage is generated by self induction action in the ignition primary coil and a high voltage is induced by mutual induction action with the primary ignition coil in the second ignition coil. The high voltage is supplied to the ignition plug in the combustion chamber, causing a spark, igniting the compressed mixed fuel. If a very small defect occurs inside the insulating material when a voltage is applied in said ignition coil, the performance of the insulation material will get worse and breakdown by a partial discharge of corona discharge. Thus, in this experiment, we are to contribute to improve the performance and ensure the reliability of the ignition coil by investigating partial discharge characteristics according to the change of voltage and temperature when a voltage is applied to the specimen of the epoxy molding ignition coil.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.722-725
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• 2003

In AC plasma display, it is very important to quantify the wall voltage induced by the wall charge accumulated on the dielectric surface. If we know the quantities of the wall voltage in each period of every sequence; reset period, address period and sustain period, then it helps us to design the optimal driving waveform for high efficiency plasma display. We develop a new method to measure the wall voltage with VDS (Versatile Driving Simulator) system. From this method the wall voltage induced by a wall charge profiles just after the reset discharge of every cells in plasma display panel can be investigated and analyzed successfully. It is noted that the wall voltage profiles are influenced by the space charge and then they are stabilized as time goes by. It is also noted that both the remaining wall charge at the previous sequence and space charges contribute to wall voltage quantities just after the reset discharge. It is noted that the wall charges contribute dominantly after a few hundreds microseconds, while the space charges have been decayed within 100 ${\mu}s$ just after the reset discharge.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.149-149
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• 2012

We introduce Helicon discharge plasma source and Laser Thomson scattering system recently finished an installation in KRISS. Laser Thomson scattering method is promising for diagnostics in Helicon plasma because a measurement by electrical probe typically used has significant errors due to the gyromotion of electrons induced by high magnetic field. However, we found that LTS is affected by magnetic field so that we applied the normalization method for processing data and the results show a clear Maxwellian distribution at various conditions of magnetic field and RF power at low energy part without distortion.

• Journal of Korean Society of Rural Planning
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• v.9 no.4 s.21
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• pp.1-7
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• 2003

This study was conducted to seek the effective water management method of the irrigation reservoirs. Joongpyong reservoir was selected for the hydrologic monitoring, and investigated from May in 1999 to December in 2001. The water level and amount of outlet discharge were measured, the stage discharge equation as a rating curve was induced, and which were compared to the irrigation water requirements calculated by a daily simulation model. The water balance of Joongpyong reservoir was analyzed, mainly on the reservoir storage ratio during irrigation period. Comparing the observed storage and simulation data, the results of the simulation were well agreed with the measured data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1110-1115
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• 2009

We studied on the design of electrical parameters for ICP(Inductively Coupled Plasma) light sources which can be effective to improve the electrical power efficiency of it. These parameters were derivated from Barkhausen theory about the oscillating condition of a ballaster. The relationships of $f-I_p$ and f-n were calculated theoretically and then these relationships were compared with the measured results about $I_p$ and power depending to a discharge length(l) of ICP light source. Finally, we can see that a specific range of induced current depending to a discharge length would be necessary to minimize the change of magnetization inductance and driving frequency at driving.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3270-3275
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• 1994

Particle trajectory visualization using laser sheet was performed to investigate the corona wind flow interactions in the one-wire and two-wire type electrostatic precipitators. The corona wind generated by corona discharge was not negligible, and strong flow interactions took place owing to the induced circulatory cells. In the case of one-wire type, as the applied voltage was increased and the cross-section mean velocity was decreased, the effect of corona wind became active. In the case of two-wire type, if upstream discharge voltage was relatively higher than downstream discharge voltage, the effect of upstream corona wind was reduced.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1391-1394
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• 2007

In this work, the discharge characteristics and temporal distribution of surface charges on the Sidoped MgO have been investigated and elucidated with the results of photon-induced surface current. Even though the Si doped MgO shows lower static voltage margin, higher luminous efficacy, and shorter statistical delay time, its discharge characteristics become deteriorated as the timing of scanning is delayed from the ramp type reset pulse down. Overall features of Si-doped MgO in discharge characteristics are well correlated with surface current characteristics.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.130-133
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• 2006

In order to study the relationship between the discharge characteristics of an ac PDP and the surface conductivity of MgO thin film, the surface current across a ring shaped MgO film was measured by exposure to monochromatic vacuum ultraviolet from the synchrotron radiation source whose wavelength ranges from 60nm to 240nm $(5.5eV{\sim}25eV)$. The experimental results show that the surface current begins to increase rapidly at the photon energy of about 9 eV which might correspond to the valence band edge of MgO. The difference in the surface current level correlate well with the differences in the preparation method of MgO films and their respective discharge characteristics such as the firing, minimum sustain voltages, address voltage margin and address discharge delay time.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.121.1-121.1
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• 2014

Recently, much attention has been given to plasma production under liquid and its applications [1]. However, most of plasma production techniques reported so far utilize high voltage dc, ac, rf or microwave power [2], where damage to discharge electrodes and small discharge volume are remained issues. As an alternative of plasma production method under liquid, we have proposed pulsed microwave excited plasma using slot antenna, where damage to the slot electrode can be minimized and plasma volume can be increased. We have also reported improvement of treatment efficiency with use of reduced-pressure condition during the discharge [3]. To realize low pressure conditions in liquid, various alternative technique can be considered. One possible technique is simultaneous injection of microwave power and ultrasonic wave. Ultrasonic wave induces pressure fluctuation with the wave propagation and is so far used for cavitation production in the water. We propose utilization of reduced pressure induced by ultrasonic cavitation for improvement of the plasma production. Correlation between the plasma production and the ultrasonic power will be discussed.