• Fashion & Textile Research Journal
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• v.10 no.6
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• pp.1036-1044
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• 2008

This research from analyzing dyed silk fabrics treated with persimmon juice by padding concludes as follows : The add on is increased as the number of padding increase and the color of the dyed fabrics holds red-yellow colors which has low brightness and high chromatic colors. The fabrics dyed with persimmon juice have properties such as 2nd grade of light fastness, 4~5th grade of perspiration fastness and rubbing fastness, and 3~4th grade of washing fastness. The dyed fabrics exposed to UV light have deeper yellow-red color than things exposed to sunlight. The silk fabrics treated premordants have shown strong yellow colors, especially the fabrics added Fe mordant have shown greenish red-yellow colors. As the padding times of dyeing with persimmon juice are increased, strength and water-repellent property are enhanced along warp and weft direction respectively but anti-crease property is decreased. Also, the dyed fabrics have good antibacterial activity and deodorization.

• Imaging Science in Dentistry
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• v.31 no.1
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• pp.17-22
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• 2001

Purpose: To compare the film density of Insight dental X-ray film (Eastman Kodak Co., Rochester, NY, USA) with that of Ektaspeed Plus film (Eastman Kodak) under manual and automatic processing conditions. Materials and Methods : Insight and Ektaspeed Plus films were exposed at three different exposure conditions with an aluminum step wedge on the films under the three different exposure times. The exposed films were processed by both manual and automatic ways. The Base plus fog density and the optical density made by exposing step wedge were calculated using a digital densitometer (model 07-443, Victoreen Inc, Cleveland, Ohio, USA). The optical densities of the Insight and Ektaspeed film versus thickness of alumimun wedge at the same exposure time were plotted on the graphs. Statistical analyses were applied for comparing the optical densities of the two films. Results: The film density of both Insight films and Ektaspeed Plus films under automatic processing condition was significantly higher over the manual processing. The film density of Insight films was significantly higher than that of Ektaspeed Plus films on both automatic and manual processing conditions. Conclusion: The radiation exposure time can be reduced when using Insight over Ektaspeed Plus film. To take the full advantage of reducing exposure time, Insight film should be processed automatically.

• Journal of Information Display
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• v.5 no.4
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• pp.18-22
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• 2004

A carbon nanotube field emission display (CNT FED) panel with a 2 inch diagonal size was fabricated through screen printing of a prepared photo-sensitive CNT paste and vacuum in-line sealing technology. After surface treatment of the patterned CNT, only the carbon nanotube tips are uniformly exposed on the surface. The diameter of the exposed CNTs are usually about 20nm. The sealing temperature of the panel is around 390 $^{\circ}C$ and the vacuum level is obtained with $1.4{\times}10^{-5}$torr at the sealing. The field emission properties of the diode type CNT FED panel are characterized. Currently, we are in the process of developing a triode type CNT FED with a self-aligned gate-emitter structure.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.2
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• pp.154-161
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• 2014

Naval ships have hull appendages which are more exposed to the outside because of its small block coefficient compared with commercial ships. These exposed hull appendages like skeg, strut and shaft line affect the maneuverability of a ship. The effect of hull appendages has considered at initial design stage to estimate more accurate maneuverability. In this paper, sensitivity analysis is used to analyze the effect on maneuverability by hull appendages. 3 DOF maneuvering equations based on Mathematical Modelling Group (MMG) model are used and propeller & rudder model are modified to reflect the characteristics of twin propeller & twin rudder. Numerical maneuvering simulations (Turning test, Zig-zag test) for benchmark naval vessel, David Taylor Model Basin (DTMB) 5415 are performed. In every simulation, it is calculated that stability indices and maneuverability characteristics (Tactical Dia., Advance, 1st Overshoot, Time of complete cycle) with respect to the parameters (area times lift coefficient slope, attachment location) of hull appendages. As a result, two regression formulas are established. One is the relation of maneuverability characteristics and stability indices and the other is the relation of stability indices and hull appendages.

• YAKHAK HOEJI
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• v.41 no.6
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• pp.692-697
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• 1997

Creatine and 3,4-Dimethylhippuric acid (3,4-DMHA), a glycine conjugate of 1,2,4-trimethyl-benzene (1,2,4-TMB) were determined in the urine of workers exposed to 1,2,4-TMB vapor. The best condition for the simultaneous determination of 3,4-DMHA and creatine by high performance liquid chromatography was obtained by reverse phase $C_{18}$ column (4.6${\times}$150mm, 5${\mu}m$) as stationary phase and 20% acetonitrile in 20mM phosphate buffer (pH 3.0) containing 4mM sodium octylsulfate(SOS)as mobile phase. The recovery of 3,4-DMHA spiked to blank urine in the range of 1~5${\mu}g$/ml was about 96%. The concentration of urinary 3,4-DMHA of workers had a positive correlation with the environmental level of 1,2,4-TMB (r=0.866). The data suggest that urinary 3,4-DMHA concentration is a useful biological index for 1,2,4-TMB exposure.

• Toxicological Research
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• v.12 no.2
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• pp.259-263
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• 1996

The preventive effects of ginseng and aloe extract on cigarette smoke-induced hepatotoxicity to Spague-Dawley rats were investigated. The experimental rats were exposed smoke by inhalation for 5 weeks, 3 times per day, and 15 minutes each time. Also ginseng and aloe extract (Group G+A), aloe (Group A) or ginseng (Group G) were administered to each group, but the positive control rats (Group C) were exposed smoke without any other special treatments. Group C showed decreased food intake and increased water consumption. Also the reduction of body weight and the increase in serumAST, ALT, triglyceride and alkaline phosphatase were observed. The relative liver weights of group C were increased and the hepatic parenchyma revealed light brownish red grossly. On histopathologic observation, the hepatocytes of group C animals exhibited diffuse swelling which narrowed the, sinusoidal lumen and disarrayed the hepatic cord-like arrangement. Diffuse necrosis of the hepatocytes was also observed. However, degeneration and necrosis of the hepatocytes were milder in group G+A. In the case of group A, the damage was moderate, while the group G showed marginal improvement from group C. Electronmicroscopically, peroxisome increased and mitochodria decreased in group C. Various hepatic damages related to smoking in group C revealed recovering tendency in group G+A. This study indicated that daily administration of ginseng and aloe could decrease and even prevent cigarette smokeinduced hepatotoxicity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.149-150
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• 2019

When concrete is exposed to fire, the decomposition of Portland cement paste results in critical damage to the concrete structure of a building. However the recovery process of the damaged concrete structure has not yet been fully elucidated. In addition, research on appropriate additives such as carbon nanotube (CNT) and nanosilica has been increasing recently, however, investigation of CNT and nanosilica incorporated cement paste after decomposition of CNT by high temperature is not fully investigated. In this study, we investigated the physicochemical properties of CNT incorporated cement paste under different temperatures ($200^{\circ}C$, $500^{\circ}C$ and $800^{\circ}C$). Also, the effects of different rehydration conditions ($20^{\circ}C$ 60% RH and in water for different curing times) on the recovery of the paste were studied. The changes in tensile strength, surface observation of the specimens were characterized. In addition, the decomposition and formation of hydrates in the paste due to the heating process were studied using X-ray diffraction. The results showed that incorporation of nanosilica enhanced tensile strength after heating to each target temperatures.

• Journal of Surface Science and Engineering
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• v.54 no.2
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• pp.62-70
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• 2021

Al2024 aluminum alloy specimens were exposed to atmospheric conditions for maximum 24 months and analyzed by electron microscopes to characterize their corrosion behavior and oxide film characteristics. As the exposure time increased from 12 months to 24 months, the number of pitting sites per 1 mm² increased from ~100 to ~200. The uniform oxidation (or non-pitting) region of the 12-month exposure specimen showed 30~120 nm thick oxide layer, whereas the 24-month exposure specimen showed 170~200 nm thick oxide with the local oxygen penetration region up to 1 ㎛ deep. There was no local corrosion area observed in the 12-month exposure specimen except pitting. However, in the 24-month exposure specimen, local oxygen penetration region was observed beneath the uniform oxide layer and near the pitting cavity. Al2024 showed two times thicker uniform oxide layer but much shallower local oxygen penetration region than Al1050, which appears to be related to low Si concentration. Further research is needed on the effects of Mg segregation near the tip of the oxygen penetration region.

• Journal of Soil and Groundwater Environment
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• v.24 no.3
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• pp.13-23
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• 2019

The purpose of this study is to suggest conceptual models based on finite numerical method that can be used to assess contaminant transport through subsurface and estimate exposed concentration at contaminated site. This study tested various assumptions of the numerical models for contaminant transport in unsaturated and saturated zones to simulate the pathways to the human exposal point. For this purpose, models for seven possible scenarios of contaminant transport were simulated using the numerical code MODFLOW and MT3D. The simulation results that showed different peak concentrations and travel times were compared. In conclusion, the potential utility of the numerical models in the site specific risk analysis suggested as well as future research ramifications.

• Corrosion Science and Technology
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• v.21 no.4
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• pp.258-272
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• 2022

Steel structures exposed to the outdoors experienced several types of corrosion, which may reduce their thickness. Since atmospheric corrosion can induce economic losses, it is important to consider the atmospheric corrosion behavior of a variety of metals and alloys. This work performed outdoor exposure tests for 10 years at 14 areas in Korea and calculated the atmospheric corrosion rate of weathering steel. This paper discussed the atmospheric corrosion behavior of weathering steel based on various corrosion factors. The average corrosion rates in coastal, industrial, urban, and rural areas were found to range from (2.83 to 4.23) ㎛/y, (2.99 to 4.23) ㎛/y, (1.72 to 3.14) ㎛/y, and (1.57 to 2.85) ㎛/y respectively. It should be noted that the maximum corrosion rate was about 6.0 times greater than the average corrosion rate. Regardless of the exposure sites, the color differences were increased, but the glossiness was reduced and there was no relationship between the corrosion rate and environmental factors and the glossiness.