• Journal of Ceramic Processing Research
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• v.20 no.5
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• pp.499-504
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• 2019

The effect of coating thickness on the contact fatigue and wear of thermal barrier coatings (TBCs) are investigated in this study. The same bondcoat material thickness (250 ㎛) are used for each sample, which allows the effect of the coating thickness of the topcoat to be investigated. TBCs with different coating thicknesses (200, 400, and 600 ㎛) are prepared by changing processing parameters such as the feeding rate of the feedstock, spraying speed, and spraying distance during APS(air plasma spray) coating. The damage size on the surface are strongly affected by the coating thickness effect. Although the damage size from contact fatigue using a spherical indenter diminish at a TBC of 200 ㎛, a high wear resistance such as a low friction coefficient and little mass change are found at a TBC of 600 ㎛. These results indicate that the coating thickness strongly affects the mechanical behavior in TBCs during gas turbine operation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1043-1047
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• 2007

Community Noise has been great concerned in public. Especially, the road traffic noise has affected too much damage on quiet living environment. In this paper, the noise barrier and reducer effect on the street has been analyzed by using the ray tracing method. The outcome of the analysis has been compared to the measurement at the street near the highway. It turns out that noise barrier and reducer decreases noise level by 7dB(A).

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.28-28
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• 2010

The secondary barrier of cargo containment for membrane LNG tank is composed of composite materials such as rigid triplex (rigid secondary barrier, RSB) and flexible triplex (flexible secondary barrier, FSB). RSB and FSB are adhered to each other using an epoxy adherent and the quality of the secondary barrier depends on the bonding strength between them. The bonding strength between RSB and FSB is greatly influenced by the surface condition of RSB prior to joining. In this study, the effect of surface condition prior to joining on the joint strength and the fracture mode occurred between RSB and FSB have been examined in order to establish a proper surface treatment method for improving the bonding strength at the temperature of $-170^{\circ}C$.

• Journal of Information Display
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• v.10 no.4
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• pp.143-148
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• 2009

The theoretical current density equations for organic semiconductors was derived according to the internal carrier emission equation based on the diffusion model at the Schottky barrier contact and the mobility equation based on the field dependence model, the so-called "Poole-Frenkel mobility model." The electric field becomes constant because of the absence of a space charge effect in the case of a higher injection barrier height and a lower sample thickness, but there is distribution in the electric field because of the space charge effect in the case of a lower injection barrier height and a higher sample thickness. The transition between the injection- and bulk-limited currents was presented according to the Schottky barrier height and the sample thickness change.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.6
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• pp.29-41
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• 2012

This study was conducted in Ningxia Hui autonomous region, located at southern part of Mu Us sand land in China. To investigate relationships between windbreak effect and installation cost of sand barriers, plastic net is utilized by using four kind of heights (0.2, 0.3, 0.4 and 0.5m) and four kind of porosities (20, 30, 50 and 70%). These heights and porosities are measured for estimating distances for effective windbreak. It is shown that porosity and the distance have a positive relationship at same heights and porosity on ground indicates a constant figure when height reaches a certain level, regardless of the porosity. This implies that there is a difference of level of windbreak with different porosities; however, distance of windbreak effect is same at the same height of sand barrier. As a result of comparison between porosity of sand barrier on the ground and installation cost in each sand barrier with various heights and porosities (16 combinations), 0.4m and 0.5m height sand barriers describe highest economical efficiency. Within two variables, we concluded that height has a higher impact on windbreak effect than porosity.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.398-405
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• 2014

Salt accumulation at soil surface is one of the most detrimental factors for crop production in reclaimed tidal land. This study was conducted to investigate the effect of capillary barriers beneath the soil surface on dynamics of soil salts at coarse-textured reclaimed tidal land. A field experiment was conducted at Saemangeum reclaimed tidal land for two years (2012-2013). Capillary barriers ($3.5{\times}12m$) were treated with crushed-stone, oyster shell waste, coal briquette ash, coal bottom ash, rice hull and woodchip at 40-60 cm depth from soil surface. Silage corn (Zea mays) was cultivated during the experimental period and soil salinity was monitored periodically. Soil salinity was significantly reduced with capillary barrier compared to that of control. Oyster shell waste was one of the most effective capillary barrier materials to control soil salinity at Saemangeum reclaimed tidal land. At the first growing season capillary barrier did not influence on corn growth regardless of types of the material, but plant biomass and withering rate of corn were significantly improved with capillary barrier at the second growing season. The results of this study showed that capillary barrier was effective on the control of soil salinity and improvement of corn growth, which indicated that capillary barrier treatment can be considered one of the best management practices for stable crop production at Saemangeum reclaimed tidal land.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.447-450
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• 1995

Using Boltzmaan equation by introducing the potential barrier scattering which buit by Hall-effect, a possible origin of giant magnetoresistance in multilayers is proposed. The calculated results may be well explain the giant magnetoresistance observed in multilayers.

• Journal of the Korean Home Economics Association
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• v.40 no.5
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• pp.15-24
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• 2002

The following research conclusions were made, relative to the experiments of the textiles of fire fighters Protective Clothing. 1. When the body protection efficiency such as the thickness, the strength and heat resistance are considered, Nomex(N) is tuned out the best outer shelf, Gore-tex(KG) the best moisture barrier, and Wool-felt(WC) the best thermal barrier. 2. In the hygienic and sanitary efficiency also, N is turned out the best outer shelf, KG the best moisture barrier, and WC the best thermal barrier in its degree of water resistance, water vapour permeability, and air permeability. 3. In the washing and maintenance efficiency, too. N is turned out the best outer shell, KG the best moisture barrier, and WC the best thermal barrier, being considered the material's rate of contraction, the changing rate of frame resistance, water resistance, and water vapour permeability. 4. When considered the frame resistance against the reflection tape and reflection efficiency, O is the best material for it marks the highest score in the frame resistance and reflective effect.

• Applied Science and Convergence Technology
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• v.26 no.1
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• pp.16-19
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• 2017

A thin metal layer of molybdenum is placed between the conventional barrier layer and the stainless steel substrate for investigating the diffusion property of iron (Fe) atoms. In this study, the protection probability was confirmed by measuring the concentration of out-diffused Fe using a SIMS depth profile. The Fe concentration of chromium (Cr) barrier layer with 10 nm molybdenum (Mo) layer is 5 times lower than that of Cr barrier without the thin Mo layer. The insertion of a thin Mo metal layer between the barrier layer and the stainless steel substrate effectively protects the out-diffusion of Fe atoms.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.1222-1227
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• 2002

Noise barrier is used to reduce traffic noise. The effect of a noise barrier depends not only on the materials, but also on the physical properties such as density, height and degree of absorption, etc. Typical absorptive noise barrier is used sound absorbing material, such as glass wool and mineral wool. The goal of this study is to develope excellent absorptive noise barrier using a polyester. Laboratory measurements were peformed with various thicknesses, density and layer of absorber in a reverberation room.