• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.6 s.113
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• pp.90-97
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• 2006

The effects of a green buffer zone to protect a residential area from air pollution from industrial facilities and traffic was examined by analyzing the case of a green buffer zone in the Shiwha industrial complex. The green buffer zone is 175 m wide. The intent was to assess the dispersion patterns of atmospheric air pollutants and the reduction in concentration around the green buffer zone. To measure atmospheric sulfur dioxide$(SO_2)$ and nitrogen dioxide$(NO_2)$ concentration, badge-type passive samplers were used and set up at 76 locations in order to measure the concentration of air pollutants with respect to the spatial dispersion. The weighted mean values of $SO_2\;and\;NO_2$ concentration were $3\~57 ppb\;and\;18\~62 ppb$ and the differences among the green buffer zone, the industrial area and the residential areas were $0.7\~1.1 ppb$. Mean values of atmospheric concentrations of $NO_2$ were similar in industrial and, residential areas and the green buffer zone. Results of the study show that the effect of the green buffer zone on reducing the dispersion of air pollutants was very low. This study also recommends that micro-climate, i.e., wind direction should be considered as a factor for planning and design of green buffer zones.

• New & Renewable Energy
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• v.17 no.4
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• pp.36-45
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• 2021

To remove the Cu secondary phase remaining on the surface of a CIGSSe absorber layer manufactured by the two-step process, KCN etching was applied before depositing the CdS buffer layer. In addition, it was possible to increase the conversion efficiency by air annealing after forming the CdS buffer layer. In this study, various pre-treatment/post-treatment conditions wereapplied to the S-containing CIGSSe absorber layerbefore and after formation of the CdS buffer layer to experimentally confirm whether similareffects as those of Se-terminated CIGSe were exhibited. Contrary to expectations, it was noted that CdS air annealing had negative effects.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4120-4124
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• 2023

High-level radioactive waste produced by nuclear power plants are disposed subterraneously utilizing an engineered barrier system (EBS). A gap inevitably exists between the disposal canisters and buffer materials, which may have a negative effect on the thermal transfer and water-blocking efficiency of the system. As few previous experimental works have quantified this effect, this study aimed to create an experimental model for investigating differences in the temperature changes of bentonite buffer in the presence and absence of air gaps between it and a surrounding stainless steel cell. Three test scenarios comprised an empty cell and cells partially or completely filled with bentonite. The temperature was measured inside the buffers and on the inner surface of their surrounding cells, which were artificially heated. The time required for the entire system to reach 100℃ was approximately 40% faster with no gap between the inner cell surface and the bentonite. This suggests that rock-buffer spaces should be filled in practice to ensure the rapid dissipation of heat from the buffer materials to their surroundings. However, it can be advantageous to retain buffer-canister gaps to lower the peak buffer temperature.

• Korean Journal of Optics and Photonics
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• v.20 no.3
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• pp.182-188
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• 2009

The surface plasmon resonance ellipsometer (SPRE), using a multiple air injection system with an extraction of air system, has been proposed and developed to minimize measurement error of signals due to diffusion of reagent into running buffer. Since the diffusion of reagent into running buffer affects the refractive index of the running buffer by changing the concentration, characteristics of binding between various bio-molecules don't appear clearly in measurement results. The diffusion between running buffer and reagent can be blocked by using an air bubble injection system. An extraction of air system is used to remove the noise signal due to unnecessary air bubbles flowing in a channel. Reliability of measurement results has been improved by using the valve system.

• Journal of the Korea Institute of Building Construction
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• v.2 no.1
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• pp.139-146
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• 2002

This study deals with the characterizing and the application like as insulation materials in the joint part in concrete surface layer and waterproofing sheet especially for roof slabs. Using steel materials and butil-rubber tape to band waterproofing sheet and concrete surface together before this waterproofing system will be applied. It can be expected to both the curability and the watertightness by coating poly-urethane 2 or 3 times with sheet surface. Therefore this waterproofing system can be possible to protect water without the damage when vapor is going out from concrete and without air pockets because of the difference temperature inside and out. This system particularly consists of air bents and elastic waterproofing sheet considering the physical damage while water can cause purely physical damage. This system is one of the most efficient ways of waterproofing system without air pocket.

• Journal of the Korean Ceramic Society
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• v.54 no.6
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• pp.492-498
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• 2017

A thermal barrier coating (TBC) with self-healing property for cracks was proposed to improve reliability during gas turbine operation, including structural design. Effect of healing agent on crack propagation behavior in TBCs with and without buffer layer was investigated through furnace cyclic test (FCT). Molybdenum disilicide ($MoSi_2$) was used as the healing agent; it was encapsulated using a mixture of tetraethyl orthosilicate and sodium methoxide. Buffer layers with composition ratios of 90 : 10 and 80 : 20 wt%, using yttria stabilized zirconia and $MoSi_2$, respectively, were prepared by air plasma spray process. After generating artificial cracks in TBC samples by using Vickers indentation, FCTs were conducted at $1100^{\circ}C$ for a dwell time of 40 min., followed by natural air cooling for 20 min. at room temperature. The cracks were healed in the buffer layer with the healing agent of $MoSi_2$, and it was found that the thermal reliability of TBC can be enhanced by introducing the buffer layer with healing agent in the top coat.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4005-4012
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• 2022

As high-level radioactive waste (HLW) generated from nuclear power plants is harmful to the human body, it must be safely disposed of by an engineered barrier system consisting of disposal canisters and buffer and backfill materials. A gap exists between the canister and buffer material in a HLW repository and between the buffer material and natural rock-this gap may reduce the water-blocking ability and heat transfer efficiency of the engineered barrier materials. Herein, the basic characteristics and thermal properties of granular bentonite, a candidate gap-filling material, were investigated, and their effects on the temperature change of the buffer material were analyzed numerically. Heat transfer by air conduction and convection in the gap were considered simultaneously. Moreover, by applying the Korean reference disposal system, changes in the properties of the buffer material were derived, and the basic design of the engineered barrier system was presented according to the gap filling material (GFM). The findings showed that a GFM with high initial thermal conductivity must be filled in the space between the buffer material and rock. Moreover, the target dry density of the buffer material varied according to the initial wet density, specific gravity, and water content values of the GFM.

• Nuclear Engineering and Technology
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• v.38 no.6
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• pp.483-488
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• 2006

Highly radioactive waste is placed in metal canisters embedded in dense clay termed buffer. The radioactive decay is associated with heat production, which causes degradation of the buffer and thereby time-dependent loss of its waste-isolating potential. The buffer is prepared by compacting air-dry smectite clay powder and is initially not fully water saturated. The evolution of the buffer starts with slow wetting by uptake of water from the surrounding rock followed by a long period of exposure to heat, pressure from the rock and chemical reactants. It can be described by conceptual and theoretical models describing processes related to temperature (T), hydraulic (H), mechanical (M) and chemical performance (C). For temperatures below 90 C more than 75 % of the smectite will be preserved for 100 000 years but cementation may reduce the excellent performance of the buffer to a yet not known extention.

• Journal of Fisheries and Marine Sciences Education
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• v.5 no.2
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• pp.128-137
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• 1993

This paper presents a new concept to reduce turbulent frictional drag by injecting micro-bubble into buffer layer of turbulent boundary layer on flat plate. The buffer layer of boundary was specified by minus velocity gradient of law of the wall. When the buffer layer region of turbulent boundary layer is filled with micro-bubble of air and viscous of the region is kept low, the velocity profile in the region should be changed substantially. Then the Reynolds stress in the buffer layer region becomes less, which guide to higher velocity gradient there. It results in reduction of velocity gradient at the viscous sublayer, which gives the reduction of shear stress at the wall.

• Analytical Science and Technology
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• v.13 no.4
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• pp.412-422
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• 2000

The polymeric FAB materials of air shower used in clean room of wafer industry have been outgassed with the dynamic headspace (ca.$100^{\circ}C$) for half an hour, and analyzed using GC-MS. The air in the clean room running air shower was sampled using sorbent tube method, and the organic compounds adsorbed in the sorbent tube were extracted using Soxhlet extraction method, and analyzed using GC-MS. The analytical results from FAB materials of air shower (electric over current relay, acryl plate. polycarbonate window, filter, fan housing, steel galvanized cold plate and canvas buffer) indicated that most of chemicals were originated from polymer fragments of FAB materials. Their analytical results have been compared with those from the air of clean room running air shower. These comparative results could lead to identify whether the sources of trace organic contaminants in clean room air are originated from the polymeric FAB material of air shower.