• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.227-227
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• 1999

Plasma display panel(PDP) is a leading technology for large-area flat panel displays. A current issue in operating the PDP cell is that the efficiency of the PDP cell is very low. To increase the efficiency of the PDP cell, the visible light needs to be maximized and the power consumption minimized. Since the excited xenons are related to the production of the visible light, it is important to optimize the cell geometry and the gas composition that produce the excited xenons more efficiently. A 2D-fluid code (FL2P) is developed and used to simulate the plasma dynamics and the radiation transport in the PDP cell. The cell is optimized with the code for various operating conditions and cell dimensions such as the voltage pulse, electrode length, electrode spacing, gap size, dielectric constant, gas mixture ratio, pressure, and pulse duration.

• Journal of Korean Society for Atmospheric Environment
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• 제23권E1호
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• pp.29-38
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• 2007

A cylindrical tube connection that has a voltage difference and is separated electrically by an insulator was modelled. The penetration efficiencies of charged particles passing through the connector tube were investigated. Typically, as the particle size decreases and the applied voltage difference increases, the penetration efficiency decreases. To assess the effect of the electrode geometry, various lengths of electric insulator and aerosol flow rate with a fixed tube length and tube diameter were used when calculating penetration efficiencies. The comparison of penetration efficiencies for various electrode geometry setups suggests that the penetration efficiency can be described as a function of the product of applied voltage and electrical mobility of charged particles. The diffusion loss from this and previous studies are compared. Further, an explicit form for penetration efficiency is provided as a function of a new non-dimensional parameter, $Es(=Z_pV/U_{avg}W);\;P_{es}=0.2{\cdot}{\exp}(-Es/0.6342)+0.8{\cdot}{\exp}(-Es/4.7914)$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.75-78
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• 2002

The dielectric properties for Ni electrode multilayer ceramic chip capacitor for Y5V has been studied with $(Ba_{0.93}Ca_{0.07})_m(Ti_{0.82}Zr_{0.18})O_2+MnO_2$ 0.2wt%, $Y_2O_3$ 0.18wt%, $SiO_2$ 0.15wt%, glass frit 1 wt% composition. The m ratio in the range of 1.006 ~ 1.012 have dielectric constant 9,500 ~ 14,500 and insulation resistance 390 ~ 460 $G{\Omega}$. Using the dielectrics, nikel electrode multilayer chip capacitor with Y5V, 104Z in EIA 0603 size specific capacitance were developed.

• 한국생산제조학회지
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• 제21권6호
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• pp.938-945
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• 2012

This research proposes FEM analysis for Tandem welding process used in wind tower and predicts optimal welding process to improve the stability of welded structures. Three dimensional elasto-plastic analyses are employed to evaluate thermo-mechanical behavior of residual stress and deformation during Tandem welding for different distance between two touches. To confirm the thermal distribution, Goldak's ellipse heat source model and the real size wind tower pipe model are utilized. Four different analyses are being performed, where in each case the distance between two electrode torches is being changed and residual stress and welding deformation are predicted. Depending on base material state, each case is divided into: Liquid (100mm), Austenite+Liquid (200mm), Austenite+Cementite (400mm), Pearlite+Cementite (800mm).

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.360-363
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• 2009

In order to improve the overall power conversion efficiency, it is very important to reduce the interface resistance of dye-sensitized solar cells (DSSCs). In this approach, tiny $TiO_2$ nanoparticles with the primary size of 10~20nm were synthesized and deposited between FTO glass and preformed $TiO_2$ layer by $TiOCl_2$ treatment, and also Pt catalysts were deposited on the counter electrode by both ion-sputter and thermal deposition to reduce the electrolyte-counter electrode interface resistance. The influence of these processes on the performace of DSSCs were discussed in terms of fill factor, short circuit current, and conversion efficiency.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.151-154
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• 2002

In this paper a mathematical model, the results of computer simulation and exprimental investigations of electrochemical machining with a too-electrode are presented. The experimental investigations were carried out in order to evaluate the influence of working voltage, initial interelectrode gap size, and metal remove rate. Accuracy of computer simulation evaluated by differences between results of experimental test and computer simulation depends on electrochemical machining coefficient, total overpotential of electrode process, current density, electrical conductivity of electrolyte, and etc. Metal removal rate would be predicted by the simulation of ECM process.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.267-271
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• 1987

The test cell for preventing the edge effect reducing the intrinsic breakdown strength of polypropylene film and measuring the intrinsic breakdown strength of the film was developed. The new approach was to develope an electrode system with an edge region which is carefully graded over an extended distance. The new test arrangement employed a central circular electrode at high voltage and a set of nine concentric surrounding rings each controlled in potential by external grading resistors to be at decreasing potentials from that at the center in 10% increments. Two different size structures using the same basic principle were tried and were both found to be successful. The test electrodes were manufactured using standard printed circuit technology and were chosen to be copper on high dielectric constant GIO board.

• 대한전기학회논문지
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• 제39권9호
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• pp.956-963
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• 1990

The general shapes of prebreakdown pulses in a discharge gap were calculated and the current pulses due to avalanche were detected in SF6 by changing the polarity of the protrusion placed on an electrode at pressures up to about 400 Kpa. The mathematical model of prebreakdown pulse development with a negative protrusion shows agreement with the observed pulses. No evidence of intense bursts of field-emitted electrons was observed. Breakdown probably results from a single avalanche developing to a critical size. However the calculated shape of prebreakdown current pulse does not agree with the observed pulses with a positive protrusion. The breakdown is preceded by multiple avalanche development at pressures less than about 200 Kpa. This observation has been interpreted as due to the formation of negative ions following photoionization in the gas which drift into the critical volume near a positive protrusion.

• 한국표면공학회지
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• 제24권3호
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• pp.162-168
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• 1991

Gas diffusion and electrolyte penetration in wetproofed gas diffusion electrodes were studied using layers of PTFE- bonded carbon. Minor variations in fabrication and testing procedures resulted in very large variations in catalyst layer wetting characteristics and permiability for reaction gas. By controlling the pore size of gas diffusion electrode carefully by varing the PTFE contents, baking temperature, baking time and ammonium bicarbonate as additive, the primary pore was decreased and the secondary pore was increased and so more reaction gas through the primary pore could be reacted at catalyst agglomertes in the secondary pore. And the cathode current density was increased to more than 400mA.$\textrm{cm}^2$ and Tafel slope value was decreased to lower than 110mA/decade.

• 한국전기전자재료학회논문지
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• 제11권4호
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• pp.321-326
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• 1998

Electrical breakdown characteristics of liquid nitrogen($LN_2$) taking into consideration for application of high $T_c$ superconductor is very important. Also $LN_2$ will be used as both coolant and insulator in superconducting generator. In this paper, we investigated ac breakdown characteristics of cryogenic nitrogen gas above a $LN_2$ for rod-to plane electrode configuration. As result the breakdown mechanism of $LN_2$is dependence on bubble effect. And breakdown voltage is a ratio on bubble s size but electrodes arrangement is to make no difference. The breakdown voltage decreases slightly with increasing flow velocity, it again decreases abruptly with increasing flow velocity. These results were interpreted as the within pressure of rod electrode and Maxwell force.