• Journal of the Korean GEO-environmental Society
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• v.16 no.12
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• pp.53-58
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• 2015

Engineers should take great care of characterizing the engineering properties of mudrock, because the uncemented mudrock can be considered as a hard rock in appearance. Therefore, the mudrock samples obtained from the cut slope in Gyeongki-do were tested to evaluate the strength characteristics of uncemented mudrock in this study. The performed tests are index properties, slake durability, and swelling tests for the classification of the mudrock for engineering practice. To evaluate the effect of water on the engineering properties of the uncemented mudrock, resonant column, triaxial compression and direct shear tests with various water contents were performed. With the increasing water contents, stiffness at very small to small strain region and the cohesion value of the strength parameters decrease. Based on the test results, engineers should take great care of evaluating the engineering properties of uncemented mudrock.

• Journal of the Korean GEO-environmental Society
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• v.14 no.5
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• pp.33-39
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• 2013

A drilling exploration in deep sea is being processed to develop new energy resource in the world. In 2007, the presence of the gas hydrate had been confirmed during the UBGH1 (Ulleung Basin Gas Hydrate Expedition 1) in the Ulleung Basin. Geotechnical properties of the deep marine sediment are important factors for assessing the safety of gas production facility and productivity from the hydrate bearing sediment. In this study, comprehensive laboratory tests are conducted to investigate the geotechnical engineering characteristics of the deep marine sediments recovered from the hydrate occurrence regions during the UBGH2 (Ulleung Basin Gas Hydrate Expedition 2) in the Ulleung Basin, East Sea, Korea. The index properties of the specimens including the specific gravity, atterberg limits, specific surface, and particle size distribution are measured, and these are compared to the results reported by previous studies. A zero-lateral strain cell, which houses bender elements, is used to determine stress-dependant characteristics and shear wave velocities with the vertical effective stresses. Furthermore, the hydraulic conductivity is calculated based on the consolidation test results.

• Geotechnical Engineering
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• v.13 no.4
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• pp.37-54
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• 1997

This paper is to investigate the bearing capacity and the failure mechanism of slope subjected to strip surcharges adjassent to embankment slope of sandy soil. Parametric model tests under plain strain condition were performed by changing width of footing, relative density of slope materials, and position of footing from the crest of slopes. For model tests, Jumunjin standard sand was used as the slope material and its relative density was 45% and 70%, respectively. The angle of slope was formed with 1 : 1.5 and 1 2. Rigid model footings, made of aluminuu were used with their widths of 4, 7, 10 and 12cm. For the position of model footing, position ratios, distance of model footing from the crest of slope divided by footing width, were 0, 0.5, 1, 2, 3, 4, 5. Failure mechanism was observed by using ink colored sands and markers inserted in model slopes. Ultimate bearing capacity obtained from tests was analyzed and compared with limit equilibrium method, limit analysis method and empirical equation. Characteristics of load-settlement curves and failure mechanism were also analyzed and compared with the existing theories. Thus, their effects on ultimate bearing capacity of model footing adjacent to slope were assessed.

• Food Science and Preservation
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• v.8 no.4
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• pp.356-361
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• 2001

This study was conducted to improve the storability of onion bulbs by assembly simple house storage and the reduce the rotteness caused by field open storage. Allium cepa cv. Changnyungdeago, late strain was used for the test at the storage condition of natural ventilation of levels 2, forced ventilation of levels 2, field open storage and 75mm, 100mm, and 125mm ventilating holes. Mean tamperature and relative humidity were not significantly different by ventilation conditions. Mean temperature was lower in forced ventilation than that of in natural ventilation and non-ventilation, and relative humidity was a little higher in ventilation treatment than those of the others. Weight loss of onion bulbs were 2.5%, 2.9%, 3%, 4.3% in field open storage, non ventilation, natural ventilation of levels 2 and forced ventilation of levels 2 respectively. Rotting rate in natural ventilation of levels 2 and farced ventilation of levels 2 were 27.7% and 25.4% respectively but 34.6% and 37.8% in non ventilation and field open storage. Therefore, the treatment of ventilation reduced the rotteness of storage onion bulbs. The smaller the size of a ventilating hole, the lower mean temperature was maintained. The relative humidity was some high in July, but didn’t showed significantly difference in August and September. With small size of a ventilating hole, the strong wind velocity was obtained, and wind velocity by position was weaker in the middle part than both ends. Rutting rates in 75㎜, 100㎜, and 125㎜ ventilating holes were 17.9%, 15.3% and 14.1% respectively.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.1
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• pp.15-22
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• 2002

This study was carried out to investigate antimutagenic and cytotoxic effects of Korean traditional Mackjang added with sea tangle powder. The content percentage of most of minerals among general composition increased by adding sea tangle powder. By the Ames test, the antimutagenic effect of ethanol extract of Korean traditional Mackjang added with 5% sea tangle powder was strongest exceeding the control, 10%, and 15% sea tangle additions. The ethanol extract (400$\mu$g/plate) of Mackjang added with 5% sea tang1e powder in the S. typhimurium TA 100 strain showed inhibition rate of 95.0% against the mutagenesis induced by MNNG. The inhibition rate of ethanol extract (400$\mu$g/plate) of Mackjang added with 5% sea tang1e powder in the S. typhimurium TA98 and TA100 strains was 81.4% and 88.8%, respectively, against the mutagenesis induced by 4NQO. Under the same conditions, the suppression against B($\alpha$)P and Trp-P-1 in the TA98 and TA100 strains were 85.3% and 91.0%, and 96.5% and 96.5%, respectively. For the anticancer effects, an investigation was done on the cytotoxicity of Mackjang added with 5% sea tangle powder on the cell lines with human lung carcinoma (A549), human hepatocellular carcinoma (HepG2), and human gastric carcinoma (KATOIII). The cytotoxicities were inhibited with increasing the extract concentration. The treatment of 1.0 mg/mL Mackjang added with 5% sea tang1e powder showed relatively strong cytotoxicity of 61.2%, 61.8% and 66.8% against A549, KATOIII, and HepG2, respectively.

• Journal of Veterinary Clinics
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• v.27 no.1
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• pp.62-65
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• 2010

Arowana (Scleropages formosus) is the most valuable group of ornamental fishes and very much in demand in the ornamental fish trade and commands high price ranging from hundreds to thousands of dollars per fish. In this paper, we described a case of mortality of arowana from a private aquarium in Korea. A bacterial pathogen from fish organs (brain, kidney, liver) was cultured, identified and confirmed using Vitek System 2, API 20E test, multiplex PCR and 16S rRNA gene sequencing. The morphological and biochemical properties of the bacterium isolated from the brain, kidney and liver of the fish were similar to Aeromonas sobria. Positive amplification products using the multiplex PCR assay for detection of A. sobria were obtained from these organs. The 16S rRNA gene of the isolates from fish was identical and exhibited 100% sequence similarity with A. sobria (AY987762.1) strain available from GenBank. This bacterium contained hemolysin gene, a virulence factor that plays an important role in outbreaks of disease and is pathogenic to humans as well as in fish. Although this opportunistic bacterium was isolated from a fish without any external symptoms, this pathogen may act as a reservoir and enhance chances of zoonosis to human such as during handling.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.505-518
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• 1997

The objective of this investigation was to compare the effects of water storage on the aspect of hardness and diametral tensile strengths of four hybrid glass ionomer cements(two compomers and two resin-reinforced glass ionomers) with a resin composite material. One composite resin(Degufill Ultra), two compomers(Dyract, Compoglass Cavifil), and two resin-reinforced glass ionomers(Fuji Duet, Vitremer) were used in this study. Cylindrical specimens were prepared and stored at $36{\pm}1^{\circ}C$ in distilled water for 10 minutes after set, and then tested on an Instron testing machine(No.4467) at 1.0 mm/min displacement rate. Vicker's hardness and diametral tensile strengths as time elapsed were measured after aging in water for 10 minutes, 1 hour, 3 hours, 1 day, 3 days, 5 days and 7 days at $36{\pm}1^{\circ}C$. During the test of diametral tensile strength, stress-strain curves were obtained, from which the compressive modulus were calculated and compared. The structure of four set glass ionomer cement mass was observed on SEM(Hitachi, S-2300) after being etched with 9.6% hydrofluoric acid for 1 minute. The results were as follows; 1. The hardness of the experimental group(compomer and the resin reinforced glass ionomer cement) did not exceed the value of control group(Degufill Ultra). 2. Vicker's hardness of the Fuji Duet tended to increase succeedingly, Dyract was decreased after 3 hours in water, and Vitremer was the lowest. 3. The control group(Degufill Ultra) presented progressively on increased diametral tensile strength with time, Fuji Duet were decreased after 3 days, Compoglass Cavifil and Vitremer were decreased after 5 days in water storage. 4. Compressive modulus of the control group(Degufill Ultra) and Dyract were increased sharply timely, Fuji Duet and Vitremer were increased smoothly by lapse of time in water. Fuji Duet were stronger than Vitremer. On the other hand, Vitremer exhibited the lowest toughness. 5. The microstructure of compomer was similar with that of the composite resin(Degufill Ultra), and the fillers in resin-reinforced glass ionomer cements were noticed. It can be concluded that mechanical properties of hybrid glass ionomer cements is weaker than composite resin, and that the compomers or the resin-reinforced glass ionomers can not substitute the composite resins. A plenty of considerations should be done on the application of them to the area under the loading and high wear has a little adverse effect on the mechanical properties on the water storage for 7 days. The further research should be needed to confirm the advantage of the compomer.

• Food Science and Preservation
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• v.9 no.1
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• pp.1-7
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• 2002

This study was carried out to investigate antimutagenic and anticancer effects of Korean traditional Kochujang added with sea tangle (Laminuia longissima). Most of the mineral content in Kochujang added with sea tangle was increased when compared to traditional Kochujang. In the Ames test, the inhibition rate of ethanol extract (200 $\mu\textrm{g}$/plate) of Kochujang added with 5% sea tangle in the S. typimurium TA100 strain showed 87.2% against the mutagenesis induced by MNNG. And also, the inhibition rate of ethanol extract (200 $\mu\textrm{g}$/plate) of Kochujang added with 5% sea tangle in the S. typhimurium TA98 and TA100 strains was 62.9% and 71.6%, respectively, against the mutagenesis induced by 4NQO. The suppression under the same condition against B($\alpha$)P and Trp-P-1 in the TA98 and TA100 strains showed 70.2% and 80.8%, and 62.9% and 73.1%, respectively. In the anticancer effects, the treatment of 1.0 mg/mL Kochujang added with 5% sea tangle showed strong cytotoxicity of 78.6% and 79.4% against KATOⅢ and HepG2, respectively.

• Food Science and Preservation
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• v.11 no.2
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• pp.214-220
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• 2004

This study was carried out to determine the antioxidative, antimutagenic, and anticancer effects of functional food manufactured from fermented soybean(FFMFS) using DPPH free radical donating method, Ames test and cytotoxicity, respectively. FFMFS extracted with ethanol and then further fractionated to n-hexane, chloroform, ethyl acetate(EtOAc), butanol and water, stepwise. Among five fractions, the EtOAc fractions showed highest electron donating activities (31.6 $\mu\textrm{g}$/mL). The inhibition rate of ethanol extract(200 $\mu\textrm{g}$/plate) of FFMFS in the S. typhimurium TA100 strain showed 84.8% against the mutagenesis induced by MNNG. In addition, the suppression of EtOAc fractions with same concentration of FFMFS the S. typhimurium TA98 and TA100 strains showed 88.7% and 92.8% inhibition against Trp-P-l, respectively. The cytotoxic effects of FFMFS against the cell lines with human lung carcinoma(A549), human gastric carcinoma(AGS) and human breast adenocarcinoma(MCF-7) were inhibited with the increase of the extract concentration. The treatment of 1.0 mg/mL FFMFS of EtOAc fraction showed strong cytotoxicities of 84.5%, 88.7% and 85.6% against A549, AGS and MCF-7, respectively.

• Korean Journal of Materials Research
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• v.22 no.11
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• pp.591-597
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• 2012

For heat exchanger applications, 2-ply clad materials were fabricated by rolling of aluminum (Al) and mild steel sheets. Effects of annealing temperature on interface properties, especially on inter-layer formation and softening of strain hardened mild-steel, for Al/mild steel clad materials, were investigated. To obtain optimum annealing conditions for the Al/mild steel clad materials, annealing temperature was varied from room temperature to $600^{\circ}C$. At the annealing temperature about $450^{\circ}C$, an inter-layer was formed in an island-shape at the interface of the Al/mild steel clad materials; this island expanded along the interface at higher temperature. By analyzing the X-ray diffraction (XRD) peaks and the energy dispersive X-ray spectroscopy (EDX) results, it was determined that the exact chemical stoichiometry for the inter-layer was that of $Fe_2Al_5$. In some samples, an X-layer was formed between the Al and the inter-layer of $Fe_2Al_5$ at high annealing temperature of around $550^{\circ}C$. The existence of an X-layer enhanced the growth of the inter-layer, which resulted in the delamination of the Al/mild-steel clad materials. Hardness tests were also performed to examine the influence of the annealing temperature on the cold deformability, which is a very important property for the deep drawing process of clad materials. The hardness value of mild steel gradually decreased with increasing annealing temperature. Especially, the value of hardness sharply decreased in the temperature range between $525^{\circ}C$ and $550^{\circ}C$. From these results, we can conclude that the optimum annealing temperature is around $550^{\circ}C$ under condition of there being no X-layer creation.