• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.575-580
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• 2013

This study focused on the identification of sound characteristics according to the configuration of sound absorption material and perforated panel dimensions. Noise barriers consist of front perforated panel, sound absorption material and back plate. Noise barriers' acoustic performance should be required to meet the NRC of 0.7. The absorbing performance of the noise barrier relies on the opening ratio of perforated panel and the efficiency of the absorbing material. This study try to find out the possibilities of applications to railway usage.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.849-854
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• 2001

A study on performance of the sound absorbing noise barrier is presented. Noise barrier of sound absorbing type is composed of the front panel, sound absorbing material, and back panel. For allowing sound path, front panel is usually perforated. The performance of the noise barrier is governed by the opening ratio of the perforated panel, sound absorption coefficient of the sound absorbing material. In this study, the effects of the opening ratio, diameter of the hole, thickness of the sound absorbing material are investigated. It is found that the thickness of the sound absorbing material must be at least 50 mm to ensure the required minimum NRC value 0.70, and the opening ratio is greater than 0.2. It is shown that the thickness of the back panel is crucial in providing required STL (Sound Transmission Loss) value. The performance of the developed noise barrier is measured, where its sound absorbing coefficient and sound transmission loss satisfy the criteria.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.2
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• pp.95-100
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• 2005

Numerical simulations and experiments were conducted to analyze the design parameters for a slim room air-conditioner. These design parameters included a fan shape, a front panel, a scroll shape, a bell mouth, a distance between a fan and a heat exchanger, etc. Each design parameter was analyzed numerically and/or experimentally in terms of the flow rate and the sound pressure level, which should be the most influential factors for developing the slim room air-conditioner. The fan with a uniform height showed a better performance than that with a linearly varying height. It is recommended to use a front grill rather than a front panel according to sound pressure levels since the front panel itself is a huge resistance to the inlet flow. A redesigned scroll shape by changing the rotational direction of a fan also contributed a lot to lowering the sound pressure level. There existed a distance between a fan and a heat exchanger, where flow rates increased effectively.

• Journal of the Korean institute of surface engineering
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• v.37 no.3
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• pp.185-190
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• 2004

Plasma Display Panel is a display device emitting fluorescent light from gas discharge between a front and a rear panel sealed together. Front and rear panel have multitude of film layers and barrier ribs in the rear panel has the largest area so releasing various gases and affecting light emitting characteristics and lifetime. The remaining gases in a barrier rib were studied by thermal desorption analysis up to $400^{\circ}C$ and main gases were $H_2$ $H_2$O, CO. During sustaining at $300^{\circ}C$, the outgassing rates from other gases were decreased but$ H_2$ kept constantly increasing until 1 hour, which can be originated from the dissociation of organics remained in the inside of barrier rib material. In $H_2$O, two distinct peaks were observed: desorption from physically adsorbed one at $l00^{\circ}C$ and from chemically adsorbed one $400^{\circ}C$. The result can be utilized in interpretation of electronic and optical characteristics and evacuation process control of PDP

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.1
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• pp.51-55
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• 2007

In this paper, a portable rotor bar fault diagnosis system for small 3 phase induction motors is suggested. For portable real-tine diagnosis system, an USB-DAQ board for collecting the 3 phase current data, three current probes, and a notebook computer are used. The LabVIEW graphical language is used for filtering, analysis, storing, and monitoring the current data. The three phase stator current are filtered and transformed to frequency level by FIT. An analysis window programed by LabVIEW is located in front panel to show the FIT results and this suggested window has a zooming function to detect the fault feature more easily near the feature frequency range which is varying by the slip frequency. To show the possibility of portable rotor bar diagnosis system, three types(healthy, one rotor bar fault, two rotor bar fault) of rotor bar are intentionally prepared and compared by the suggested window of front panel. Experimental results are shown that a suggested diagnosis system is applicable to portable diagnosis system and the rotor bar fault is detected by the frequency window in front panel programed in LabVIEW graphical language.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.31-34
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• 2009

We investigated the effect of relative dielectric constant of front dielectric layer on the efficacy of plasma display panel. Dielectric materials with relative dielectric constant of around 6 and 7 were developed. When the front dielectric layer had a low relative dielectric constant, power consumption decreased more than luminance did. And it led to efficacy enhancement. However, the minimum sustain voltage increased.

• Journal of Information Display
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• v.9 no.3
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• pp.28-32
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• 2008

Low sustained voltage $(V_s)$ and high luminous efficiency (lumen/Watts) are required for the enhanced performance of an AC PDP. Both are not realized in the same condition, however, because luminous efficiency decreases when the sustained voltage is lowered in most cases. In this study, the three design factors in the front panel of a PDP, i.e., the thickness and position of the bus electrode and the thickness of the dielectric layer, were chosen to investigate how they affect the sustained voltage and the luminous efficiency, and to find a way to optimize them. Two values were given to each of the three design factors, and experiments were done via full factorial design, i.e., with a total of eight conditions, using a 3-in.diagonal test panel. The changes in the sustained voltage and the luminous characteristics were explained in connection with the discharge characteristics of the PDP cells.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.678-682
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• 2007

It is conducted that study on corner crack protection for various thermal environment in a flat panel display. Most of the consumer electronics consist of a plastic and a metal structure. And different properties of materials could cause failure of structural reliability due to the various operating temperatures. Especially for front bezel with thin and slender structure, the effect of temperature is significant, and the design for crack protection is crucial for thermal reliability of displays. In this study, it is prescribed the behavior of the front bezel in flat panel display for various operation temperatures and proposed design parameters to ensure the structural reliability of displays.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.632-634
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• 2002

Transparent dielectric layer having color-filter function in front panel for PDP(Plasma Display Panel) was successfully fabricated and characterized. Transparent dielectric layer in front panel was made of glass based on $PbO-SiO_2-B_2O_3$ ternary system. The change of properties with content variation of oxide colorants in transparent dielectric layer having color-filter function was systematically accessed. It was demonstrated that the optimized content of oxide colorants to parent glass could greatly increase up contrast ratio and color temperature without significantly degrading luminance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.11-12
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• 2011