• Tunnel and Underground Space
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• v.17 no.1 s.66
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• pp.26-31
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• 2007

The 11 nuclear power plants have been taking charge of more than 40% of the total electrical power development in Korea. In addition to the existing nuclear power plants at Gori, Wolsung, Youngkwang, etc., the 12 nuclear power plants are expected to be newly established until 2006. So, the 23 nuclear power plants will produce the electric power as much as more than 50% of the national gross production. However the nuclear power plants are inevitably generating the detrimental atomic wastes. Therefore the disposal techniques for the nuclear wastes should be ensured considering a very high safety factor. According to the basic researches in KAERI, the underground disposal repositories are reported to be most favorable for Korea. The KBS-3 disposal system has been strongly suggested by KAERI and this system has a deep tunnel with several disposal boreholes in tunnel floor. The nuclear wastes, which are sealed tightly in a canister, will be disposed in these boreholes. Considering the disposal tunnel in a great depth, the in-situ stress regimes will affect severely the tunnel stability. Consequently the effect of the in-situ stresses on the disposal tunnel and the role of the in-situ stresses in tunnel stability analysis are examined by the numerical studies.

• Food Science and Preservation
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• v.15 no.3
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• pp.347-351
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• 2008

The effect of microperforated packaging films on fresh-cut apples was studied Apples (Malus domestica Borkh. cv. Red Delicious) were cored and cut, packaged in laser microperforated film or non-microperforated polyolefin film, and stored for 3 weeks at 4C. The flesh firmness of apples packaged in microperforated film during the storage period was significantly higher than that of apples packaged in non-microperforated film, and the level of soluble solids was also higher. The browning index, titratable acidity, pH, acetaldehyde and ethanol levels were not affected by microperforation. These results show that microperforated films could be used for retention of flesh firmness in fresh-cut apples.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.7-11
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• 2008

This paper presents the experimental results on the oil leakage characteristics of stem seals depending on the driving distance in LPG vehicle. The increased speeds of the camshaft and oil temperatures do not affect to the oil leakage of the seals because of the low level of driving distances less than 40,000 km. But the increased driving distance over 50,000 km to 100,000 km shows a rapid deteriorating the sealing performance, which may increase the oil leakage through the rubbing surfaces between the poppet valves and stem seals. In this result, the stem seal may be exchanged about the driving distance of 50,000 km to 60,000 km with a currently used stem seal in LPG car. Thus, the stem seal for a poppet valve should be resigned for the increased durability and long life.

• Restorative Dentistry and Endodontics
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• v.30 no.1
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• pp.31-37
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• 2005

The aim of this study was to evaluate the effectiveness of sealer placement in simulated root canal extensions. Forty resin blocks were attained from the Endo-training Bloc. In each block. The simulated root canal was made with $\#20$, 80taper GT file. After each block was longitudinally split into two halves, a standardized groove was prepared on one canal wall of two halves to simulate the canal extensions with various irregularities. The two halves of each block were assembled and all simulated root canals were obturated by single cone method with AH26 sealer. Four different methods of sealer placement were used: group A, $\#20$ K-file; group B, ultrasonic file; group C, lentulo spiral; group D, EZ-Fill bi-directional spiral. All obturated blocks were stored in $100\%$ humidity at $37^{\circ}C$ for 1 week, Using a low speed saw, each block was sectioned horizontally. Images of the sections were taken using a stereomicroscope at $\times$ 30 magnification and a digital camera. The amount of the sealer in the groove was evaluated using a scoring system, a higher score indicated better sealing effectiveness. The data was statistically analysed by Fisher's Exact Test. The sealing score was the lowest, specially at the middle area of canal extensions in group A, and that was statistically significant difference from other groups. In conclusion, the ultrasonic file, lentulo spiral and EZ-Fill bi-directional spiral were effective methods of sealer placement in simulated canal extensions. The K file was the least effective method, specially at the middle area of canal extensions.

• Analytical Science and Technology
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• v.20 no.4
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• pp.261-267
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• 2007

The 20 L small chamber test method is to evaluate pollutants such as TVOC, formaldehyde emitted from building materials. This method was only designed to evaluate the surface emission of sample exposed in the chamber. In this method, building materials cut with a fixed standard size are fixed in a sample sealing box. The sample sealing box is put into the 20 L test chamber. This chamber is ventilated at a standard air change rate with purified air for 7 days then the sample from the chamber is collected and analyzed to measure the emission rate of TVOC and formaldehyde. In this method, however, if the sealing box does not guarantee airtightness, accurate evaluation for the building materials can not be achieved due to the pollutants emitted from edge of the sample so called, edge effect. This edge effect can be much greater when evaluating panels such as plywood, flooring due to their surface treatment. In this study, flooring was tested to check airtightness of the sample sealing box with analytic results between 1L and 20 L test chamber. Furniture materials like LPM coated one side surface treatment and MDF coated both sides surface treatment with LPM were tested to identify whether the improvement of the sample sealing box airtightness is possible with the comparison between existing and improved test method that low VOC emission tape was used to seal the sample edge. After 7 days, MDF TVOC emission rate was different according to the existence and nonexistence of tape. The emission rate of the existing test method was $0.009mg/m^2h$ and that of improved test method was $0.003mg/m^2h$. Relative standard deviation for the existing test method was $0.004mg/m^2h$ and relative standard deviation for the improved test method was $0.002mg/m^2h$ when the same sample was analyzed three times. The improved test method in this study using low VOC emission tape was effective and able to reduce the heterogeneous effect of the edge from the sample sealing box.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.4
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• pp.347-353
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• 2002

A structure of a glass electrode-type pH sensor for measuring any concentration of $H^+$ in an aqueous solution was embodied with bulk micromachining technology. Two open well structures were formed, and a reference electrode was secured by the Ag/AgCl thin film in the sloped side of the etched structure. A sensitive membrane of an indicator electrode for generating a potential by an exchange reaction to $H^+$ was made with a glass containing Na 20% or more finely so that its thickness might be $100{\mu}m$ or so, and then it was bonded to one pyramidal structure. A liquid junction for a current path was formed by filling an agar in the anisotropically etched part of the Si wafer, which had a size of $50{\mu}m{\times}50{\mu}m$, and then bonded it to the other. After complete fabrication of each part, it was filled with a 2M KCl reference solution and encapsulated the sensor structure with a cold expoxy. The potential value of fabricated pH sensor was about 90mV/pH in the standard pH solutions.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.130-136
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• 1986

'Shingo' pears were seal-packaged in polyethylene (PE) film with different thickness of 0.04. 0.06, 0.07, and 0.08mm and stored for five months in an experimental storehouse with the temperature varyine 0 to $7^{\circ}C$ and relative humidity varying 86 to 89%. The atmosphere in PE film bags was modified to 5-l4% oxygen with 3-5% carbon dioxide depending on the film thickness and the storage period. Packaging of pears with PE film effectively reduced the weight loss, which resulted in good appearance after 5 months' storage, while non-packaged pears showed a slight wilt. Decay occurrence was not significantly different among the treatments. but role browning occurred a little more in packaged lots than in non-packaged lot. The sensory panel rated the pears front 0.07mm-thick bag highest in flavor, texture, and juiciness, which might be due to the high sugar content and low titratable acidity. The firmness of pear flesh decreased with the stogare time and its change was found to be highly correlated with that of cellulase activity (correlation coefficient= -0.946). Thisresult indicated that cellulase might be one of the enzymes responsible for the softening of pear fruit during storage.

• Food Science and Preservation
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• v.13 no.1
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• pp.1-7
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• 2006

The effects of packaging material and method on quality of fresh-cut mushrooms (Agaricus bisporus Sing.) were investigated in terms of weight loss, surface color, phenolics, vitamin C and sensory characteristics during storage at $5^{\circ}C$. The fresh-cut mushrooms were subjected to passive, gas exchange and vacuum packaging conditions at st. Polyethylene film (PE), polypropylene film (PP), anti-fogging film (AP) and pen orated film (PF) were used for the passive packaging. The mixed gas of $5\% CO_2/\;2\%O_2$ (MA1) and $10\%CO_2/\;2\%O_2$(MA2) were applied for the gas exchange packaging. The respiration rate of sliced mushroom was 1.27 times higher than intact mushroom at $5^{\circ}C$. Gas concentrations in the passive packaging were $1-2\%\;O^2\;and\;5-16\%m$ during storage of sliced mushrooms for 14 days at $5^{\circ}C$, and levels of the gases were different by the films used The mushroom in perforated film (PF) showed the highest weight loss of $4.56\%$. Anti-fogging film (AF) was somewhat effective for prevention of the weight loss compared with other films after 14 days storage. The mushrooms in MA1 and MA2 packages showed lower delta L value than in other films. PE packaging mitigated decrease of free and bound phenolics during storage. The mushrooms in MA2 kept better quality in sensory aspect, and then in MA1, PE and PP in order during storage at $5^{\circ}C$.

• Pediatric Infection and Vaccine
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• v.8 no.1
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• pp.94-100
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• 2001

Purpose : Enterovirus is a common cause of aseptic meningitis and nonspecific febrile illness in young children. During the summer and fall months, enterovirus-infected young children are frequently admitted and evaluated to rule out bacterial sepsis and/or meningitis. The purpose of this study was to evaluate the relationship between nonpolio enterovirus infection and febrile illness in infants under 3 months of age during the summer, fall months by using a stool culture to identify the presence of enterovirus. Methods : Patients included febrile infants under 3 months of age admitted to Masan Fatima Hospital for sepsis evaluation from May 1999 to September 1999. Cultures were performed from stool and Cerebrospinal fluid samples and then were tested for enterovirus infection. Viral isolation and serotype identification were performed by cell culture and immunofluorescent testing. Enteroviruses not typed by immunofluorescent testing were confirmed by reverse transcription-polymerase chain reaction. Results : A total of 44 febrile infants were enrolled; of those, 20(45%) were positive for enterovirus. Two enterovirus culture-positive infants had concomitant urinary tract infection and one had Kawasaki disease. All infants infected with an enterovirus recovered without complications. Serotype of 20 enteroviruses were isolated from stool, 3 of echovirus type 9, 1 of echovirus type 11, 1 Coxsachievirus type B4, 15 of untyped enteroviruses. One untyped enterovirus was isolated in the CSF. Conclusion : Nonpolio enterovirus infections are associated with nonspecific febrile illnesses in infants under 3 months of age.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.3
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• pp.410-424
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• 2011

This study was investigated for the purpose of obtaining basic data which can be applied to processing of canned sea mussel using tomato paste. Shell were washed, and then steamed and shucked. Sea mussel meat was prepared with ratio of sea mussel 90g, tomato paste sauce 65g(tomato paste 42%, gum guar 1.0%, salt 2.0%, starch syrup 2.0%, cooking wine 1%, water 52%). The sea mussel meats were packed with vacuum seamer in 301-3 can, and then sterilized for various F0 value(F0 8-12 min.) in a steam system retort at $118^{\circ}C$. The factors such as pH, VBN, amino-N, total amino acid, free amino acid, chemical composition, color value (L, a, b), texture profile, TBA value, mineral, sensory evaluation and viable bacterial count of the canned sea mussel produced with various sterilization condition(F0 8-12 min.) were measured. The same element was also measured during preservation. The results showed that the product sterilized at F0 8 min. and preserved for 90 days were the most desirable.