• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.13-17
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• 2006

We investigated the effect of sustain electrode gap variation with high Xe content in an ac Plasma Display Panel through two-dimensional numerical simulation to understand the inherent high luminous efficiency mechanism. For the low Xe content, the optimal sustain electrode gap turned out to be about 200 ${\mu}m$, but with higher Xe content, the VUV generation efficiency increased as the electrode gap increases beyond 200 ${\mu}m$. We found that it is due to higher electron heating efficiency in the cathode sheath under the condition of long electrode gap and high Xe content.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.673-680
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• 2019

GAP or GAP-co-BO based energetic thermoplastic elastomers (ETPEs) were synthesized by changing the hard segment content percent in the range of 30~45% by 5% difference. Thermal and mechanical properties of GAP-co-BO based ETPEs were compared to those of GAP based ETPEs. FT-IR results showed that the capability of forming hydrogen bond increases with increasing the hard segment content in GAP/GAP-co-BO based ETPE, and also the GAP-co-BO based ETPEs are stronger than GAP based ETPEs in the hydrogen bond formation. DSC and DMA results showed that the glass transition temperature (T_g) of GAP based ETPEs increased with the increment of the hard segment content, while the T_g of GAP-co-BO based ETPEs was maintained even the hard segment content increased. The storage modulus at room temperature of the GAP-co-BO based ETPEs was higher than that of the GAP based ETPEs. This was due to the strong phase separation behavior of the hard and soft segment of GAP-co-BO based ETPEs, which further resulted in the stronger breaking strength and lower tensile elongation at break point for GAP-co-BO based ETPE than the GAP based one.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.11
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• pp.796-805
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• 1987

The flashover voltages have been investigated for spacer and unbridged-gap in SF6-N2 gas mixtures up to the value of 760(torr. cm), The gap was stressed by DC source The results obtained are as follows` 1) The flashover voltages for an unbridged gap and for a spacer in SF6, N2 and SF6-N2 gas mixtures follow the Paschen's curve. 2) The polarity effects was not observed in both unbridged gap and a spacer which had per ect contact with an electrode. The flashover voltages for negative polatity are lower than those for positive polarity in case of imperfect contact. 3) 3%flashover voltage is decreased by putting a spacer which had perfect contact with an electrode. The spacer which has a gap void shows the lowest flashover voltage. 4) The lowest spacer efficiency was obtained with higher gas pressure & large amount of N2 content. The flashover voltages depend on the gas pressure rather than the spacer efficienty at low value of pd. 5) The flashover voltages of gas mixtures of N2 with SF6 are relatively high, even though the amount of SF6 gas content is small.

• The Korean Journal of Ecology
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• v.18 no.1
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• pp.179-188
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• 1995

Death patterns of gap-makers and changes of environmental factors in gaps formed by disturbance were studied in Pinus densiflora forests of Youngwol, Mt, Mansu, Mt. Songni, Uljin, and Mt, Obong in Korea. Death pattern of gap-makers showed that standing deat type was the most frequent in all the study areas. Longevity of Pinus densiflora was about 140 years, which was about half of that of the temperate deciduous broad-leaved trees. size of gaps were distributed from $20m^2$ to $235m^2$, more than 80% of those were gaps created by death of two or more trees. Relative light intensity and water content of soil in gap area were higher than those in non-gap area and those in the central part of gap were the highest.

• Journal of Ginseng Research
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• v.17 no.2
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• pp.145-147
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• 1993

The amounts of ginseng acidic polysaccharide (GAP) in red ginseng (Panax ginseng) were higher than those of wild and cultured Panax quinquefolius, Panax notoginseng as well as white ginseng (Panax ginseng). In white ginseng, there is no difference in the GAP amount among root ages or sizes. Also, the GAP amount of red ginseng body was similar to that of ginseng rhizome, but was higher than that of leaf and epidermis.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.55-58
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• 2004

High Xe-content PDP characteristics are discussed. A high efficacy, up to 5 lm/W for a 50% Xe in Ne gas mixture, is realized in 4-inch color PDP test panel designs with low cost stripe-type barrier rib structures, that are powder blasted in soda lime glass. Furthermore, for a high Xe-content a high luminance can be obtained with a relatively small electrode area. Therefore the inter cell gap and the driving margin can be increased in a stripe-type barrier rib structure. Finally, for a high Xe-content the panel lifetime increases, due to increasing luminance and firing voltage stability. Clearly, these findings may direct the design development for next generation PDPs towards a high Xe-content

• 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.

• Journal of the Korean Society of Fashion and Beauty
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• v.2 no.2 s.2
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• pp.93-100
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• 2004

This study is to measure the heavy metal content of permanent wave products which on marketing correctly as estimating the extent of exposure by a hair permanent wave scientifically. We would like to prevent an affair from arising health obstruction as to the heavy metal who is using those and also show the basic data for proposing the new standard. The results were as follows.: in case of the average heavy metal content for a wave type thioglycol acid ingredient includes 1.61ppm(Pb), 0.03ppm(Cd), 0.05ppm(Ni), 0.27ppm(Mn), 0.82ppm(Cu) and those were recognized the significant gap between products all the heavy metals. In case of a cysteine acid ingredient includes 0.86ppm(Pb), 0.01ppm(Cd), 0.05ppm(Ni), 0.20ppm(Mn) and 0.66ppm(Cu) and those were recognized the significant gap between products except a nickel. Straight type of permanent wave reductant includes 2.11ppm(Pb), 0.01ppm(Cd), 0.27ppm(Ni), 0.66ppm(Mn), 2.53ppm(Cu) and those were recognized the significant gap between products all the heavy metals. Permanent wave reducing agent includes 1.43ppm(Pb), 0.01ppm(Cd), 0.09ppm(Ni), 0.66ppm(Mn), 0.75ppm(Cu) and those were approved the significant gap between products except a cadmium. Exposure level of the heavy metal contents per onetime permanent waving were 242.3ppm(Pb), 2.5ppm(Cd), 17.7ppm(Ni), 89.0ppm(Mn), 174.7ppm(Cu).

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.199-208
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• 2021

The extrudability of 3D printed concrete and its member strength can be highly influenced by water cement ratio (W/C) and printing time gap (PTG). In this study, mold cast specimens and 3D printed specimens were fabricated with variables of W/C ratio and PTG, and their shear bond strength and interlayer surface moisture content were measured and analyzed. The test results showed that the shear bond strength is greatly influenced by the amount of interlayer surface moisture. It is thus recommended that proper amount of interlayer surface moisture with respect to PTG needs to be maintained to have a required interlayer shear bond strength. In addition, further research is required to estimate the effect of many environmental factors that can influence the interlayer surface moisture content.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.194-200
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• 2001

In this study, the optical properties of diamond-like carbon(DLC) films, which was synthesized by 13.56 MHz rf plasma enhanced chemical vapor deposition system(PECVD), were investigated. We observed the variation of the transmittance and optical band gap with respect to deposition condition. The change of the transmittance and optical band gap of the DLC films were investigated as a function of RF power, working pressure, and additional gas. The optical band gap decreased with the increase of RF power and working pressure. We could verify the bond structures change of DLC films by observing the content of hydrogen using FT-IR spectroscopy. And the addition of hydrogen and nitrogen decreased the optical band gap by the breakage of C-H bond of DLC films during the deposition.