• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.316-319
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• 2007

In this paper, high precision molding process was developed using a soft mold to fabricate fine closed-types of the barrier ribs for PDP. A green sheet was employed to fabricate the barrier ribs in this process. The soft mold with good demolding characteristics was replicated from a master mold. An optimal forming load which would not fracture the soft mold was also determined. The barrier ribs of rectangular type with upper width of $30\;{\mu}m$ would be fabricated by this process.

• Journal of the Korean Ceramic Society
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• v.48 no.5
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• pp.396-403
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• 2011

In this study, we investigated the mechanical behaviors of layered thermal barrier coatings by indentations. Various single and double-layered thermal barrier coatings were deposited by air plasma spray process using different type of commercialized YSZ (Yttria stabilized zirconia) starting powders. Indentation stress-strain curve, load-displacement curve and hardness of the single and the double-layered thermal barrier coatings were obtained experimentally and analyzed. The indentation damages at the same loads were compared, and thus, the results depend on the structure of each coating. The result indicates improvement in damage resistances from tailoring of layered structures in the component of gas turbine system is expected.

• Applied Science and Convergence Technology
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• v.26 no.4
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• pp.74-78
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• 2017

The discharge characteristics of the radio frequency (RF) surface dielectric barrier discharge have been simulated for the investigation of the ratio of the ion transit time to the RF period. From one-dimensional particle-in-cell (PIC) simulation for a planar dielectric barrier discharge (DBD), it was observed that the high-frequency driving voltage confines the ions in the plasma because of a shorter RF period than the ion transit time. For two-dimensional surface dielectric barrier discharges, a fluid simulation is performed to investigate the characteristics of RF discharges from 1 MHz to 40 MHz. The ratio of the peak density to the average density decreases with the increasing frequency, and the spatiotemporal discharge patterns change abruptly with the change in the ratio of ion transit time to the RF period.

• 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.

• Journal of the Semiconductor & Display Technology
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• v.8 no.2
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• pp.49-53
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• 2009

The oxygen barrier films were formed on poly(ethylene terephthalate) (PET) substrate by a sol-gel process using 3-aminoproprytrimethoxysilane (APTMOS). The effects of solvent type, coating times and incorporation of fumed silica on oxygen permeability coefficient were investigated. The APTMOS coating film prepared from methanol as a solvent exhibited higher oxygen barrier properties than that using THF. The oxygen permeability coefficient of coated film with APTMOS/methanol by coating 7 times was measured to be $2.28{\times}10^{-6}$, while that of PET film was $1.16{\times}10^{-4}$ GPU. The addition of fumed silica does not affect the oxygen barrier properties. It may be explained that silica particles disrupt chain packing, which leads to an increase in free volume for permeation.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.93-93
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• 2003

• Fire Science and Engineering
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• v.32 no.1
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• pp.66-75
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• 2018

A barrier installed within a rack plays a significant role in delaying the initial spread of fire but it can be an obstacle to a ceiling-type sprinkler installed for extinguishing fires and for supplying fire extinguishing water. An in-rack sprinkler and a barrier can be applied at the same time, but a study on a barrier's ability to delay fire spread or its effect on the in-rack sprinkler is needed. Accordingly, this study examined the effect of a barrier on the delay of fire spread and the in-rack sprinkler according to installation conditions through the reduced scale fire test. As a result, the delay in fire spread increased more than four times when a horizontal barrier and a vertical barrier were installed at the same time. The temperature was also increased two to three times with the compartment, resulting in the early operation of the in-rack sprinkler.

• Membrane Journal
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• v.25 no.2
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• pp.85-98
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• 2015

A global trend of replacing metal or glass containers with polymer-based packaging materials has been prevalent in the food packaging industry due to their ease in processibility, excellent transparency, and good cost efficiency. Barrier polymers tend to show low permeabilities for atmospheric gases such as oxygen, carbon dioxide, and water vapor, which allow them to be utilized in the food and beverage packaging industry. With the current global trend, expansion of polymeric packaging materials to new markets such as oxygen sensitive juices, flavored water, and energy drinks requires improved $CO_2$ and $O_2$ barrier properties. The improvement of the existing polymer-based barrier platform will enable a rapid market impact. In this paper, the current barrier technologies such as (1) antiplasticization-induced barrier materials, (2) synergistic effect of antiplasticization and crystallization, (3) new barrier polymers, (4) nanocomposite materials, and (5) polymer blending are introduced with their characterization techniques for the development of advanced packaging materials.

• Journal of KSNVE
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• v.9 no.3
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• pp.466-471
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• 1999

The prediction methods of diffraction field in barrier has beenreported much about the infinite length barrier and it is very few work that reasonable sound source was used in experiment. This study, however, has worked about the several model barrier with acoustic scale model experiment. In the case of scale model experiment, it is difficult to use the kind of source with sufficiently characteristics. A spark discharge sound source with the high repeatability, broad band spectra, small size and omnidirectivity has veen used for the prediction of diffraction field. Several model barriers with different length on the ground were considered for the experiment and compared with the the results calculated by the approximation.

• Journal of KSNVE
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• v.6 no.2
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• pp.245-251
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• 1996

This study is to suggest the improved noise barrier which is harmonized with surrounding landscape and maintained the similar reduction of reflected sound and diffraction effects in comparison with the aluminum noise barrier of absorbing type which is formed a great majority in Korea. In this study the two improved models of noise barrier(Diffuse and Disperse type) were designed and compared with the noise barriers of absorbing type in the acoustics performance (the reduction of reflected sound and diffraction effects) through the field and full-scale experimental measurement. As these two models have the same acoustic performance as the noise barrier of aluminum absorbing type, it is suggested that these models can be applied to the improved noise barrier as an alteration of aluminum absorbing type barrier.