• Nuclear Engineering and Technology
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• v.29 no.2
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• pp.93-98
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• 1997

Air-oxidation experiments on unirradiated and irradiated UO$_2$ were performed at temperature from 150 to 375$^{\circ}C$ for investigating the long-term storage behavior of spent PWR fuel. The rate of oxidation was monitored by a thermogravimetric analyzer(TGA) and an X-ray diffraction(XRD). The correlation between the onset-time for U$_3$O$_{8}$ formation and temperature was given as follows, logt(hr) = -12.89+7650/T(K), 423$_2$ pellet, the oxidation rate of irradiated UO$_2$ increase more rapidly at the initial stage and shows a lower saturation point at the later Stage. The Oxidation rate of high bumup UO$_2$ and gadolinia-doped UO$_2$(Gd$_2$O$_3$-UO$_2$) were observed to be much slower than that of unirradiated UO$_2$ pellets.s.

• Korean Journal of Human Ecology
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• v.22 no.2
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• pp.375-389
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• 2013

This survey was conducted to compare the housewife's food habit and food purchase behavior on healthy dietary life. The questionnaires were collected from 151 working housewives and 159 housewives in Daejeon. The average meal time was 20~30 min., 67.6% of respondents ate breakfast and bap with guk(72.9%) was the most favourite foods. Almost half of them ate egg, fruit, vegetable everyday. They concerned highly about less intake of frozen foods(64.2%) and food additives(61.6%) for wellbeing dietary life. Because of close distance and various foods items, big discount store was chosen as food purchase place. The most considering purchase factor was food additives in working housewife and nutrition in housewife(p<0.05). In grocery shopping, working housewife considered children and their husbands(p<0.05). The most important purchase factor was the freshness in vegetables fishes fruits seaweeds eggs. TV or Radio was utilized the most frequently to obtain the useful knowledge on healthy foods. It is suggested that practical information should be offered housewives to purchase proper foods within their income and to manage dietary life according to their family's health condition.

• Korean Journal of Materials Research
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• v.31 no.7
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• pp.375-381
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• 2021

Chitosan powder is synthesized by a deasetylation process of chitin, obtained from processing of dried shrimp shell powder. Subsequently, chitosan (CS) membranes filled by montmorillonite (MMT) particles and phosphotungstic acid are prepared, and characterized by FT-IR and SEM. The morphology, obtained by SEM for the composite membrane, showed that MMT filler is successfully incorporated and relatively well dispersed in the chitosan polymer matrix. Water and methanol uptake for the CS/MMT composite membranes decrease with increasing MMT loadings, but IEC value increases. In all prepared CS/MMT composite membranes, the CS membrane filled by 5 wt% MMT particles exhibits the best proton conductivity, while that with 10 wt% MMT loading exhibits the lowest methanol permeability; these values are 2.67 mS·cm^-1 and 3.40 × 10^-7 cm²·s^-1, respectively. The best membrane selectivity is shown in the CS/MMT10 composite membrane; this shows that 10 wt% filled MMT is the optimum loading to improve the performance of the chitosan composite membrane. These characteristics make the developed chitosan composite membranes a promising electrolyte for direct methanol fuel cell (DMFC) application.

• Coupled systems mechanics
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• v.2 no.4
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• pp.375-387
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• 2013

Soils consist of an assemblage of particles with different sizes and shapes which form a skeleton whose voids are filled with water and air. Hence, soil behaviour must be analyzed by incorporating the effects of the transient flow of the pore-fluid through the voids, and therefore requires a two-phase continuum formulation for saturated porous media. The present paper presents briefly the Biot's basic theory of dynamics of saturated porous media with u-P formulation to determine the responses of pore fluid and soil skeleton during cyclic loading. Kelvin elements are attached to transmitting boundary. The Pastor-Zienkiewicz-Chan model has been used to describe the inelastic behavior of soils under isotropic cyclic loadings. Newmark-Beta method is employed to discretize the time domain. The response of fluid-saturated porous media which are subjected to time dependent loads has been simulated numerically to predict the liquefaction potential of a semi-infinite saturated sandy layer using finite-infinite elements. A settlement of 17.1 cm is observed at top surface. It is also noticed that liquefaction occurs at shallow depth. The mathematical advantage of the coupled finite element analysis is that the excess pore pressure and displacement can be evaluated simultaneously without using any empirical relationship.

• Kyungpook Mathematical Journal
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• v.58 no.2
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• pp.361-375
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• 2018

The object of the present paper is to study super quasi-Einstein manifolds. Some geometric properties of super quasi-Einstein manifolds have been studied. We also discuss $S(QE)_4$ spacetime with space-matter tensor and some properties related to it. Finally, we construct an example of a super quasi-Einstein spacetime.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.263-266
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• 2009

The mainly objectives of this study was a combustion dynamics and instability characteristics in a model gas turbine dump combustor which is the scale down of GE 7FA+e DLN 2.6 gas turbine combustor. Model gas turbine injector has 2-stage swirl vane and it’s reduced 1/3 size of the original one. The shape of plenum and combustor were designed for similar acoustic characteristics. Inlet air was preheated to $200{\sim}400^{\circ}C$. The flow velocity at mixing nozzle was 30 to 75 m/s and equivalent ratio was 0.4 to 1.2. The combustor length was varied for different acoustic characteristics to $375{\sim}700\;mm$. As the result, this research have been show the combustion instability was observed at lower equivalence ratios ($\Phi$ < $0.5{\sim}0.6$) and higher equivalent ratios ($\Phi$ > $1.1{\sim}1.2$).

• Natural Product Sciences
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• v.25 no.1
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• pp.11-15
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• 2019

Lauraceae is a family medicinal plant whose tubers possesses antimicrobial, and cytotoxic, such as antiparasitic and anti-inflammatory special effects and has been used for the medicine in the cure of hepatitis and rheumatism. The antimicrobial activities of bioactive compounds including one neolignan; kunstlerone (1) and two alkaloids include isocaryachine (2) and noratherosperminine (3) as well as crude hexane, methanol and dichloromethane extracts were evaluated. Additionally, the effect of compounds 1, 2 and 3 were evaluated on A549, PC-3, A375, HT-29 and WRL-68 cell lines. In conclusion, kunstlerone 1 showed moderate cytotoxicity against various cancer cell lines such as A549, PC-3, A375, HT-29 and WRL-68, respectively with $EC_{50}$ values of 28.02, 26.78, 33.78, 33.65 and $16.46{\mu}g/mL$. The crude methanol extract showed antigrowth activity against S. pyogenes II and B. cereus, with MICs of $256{\mu}g/mL$. The compounds kunstlerone (1), isocaryachine (2) and noratherosperminine (3) showed complete inhibition against P. shigelloides, with MIC ${\leq}60{\mu}g/mL$ compare to ampicillin, as a positive control, which showed antigrowth activity against P. shigelloides at MIC $10{\mu}g/mL$.

• Nutrition Research and Practice
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• v.5 no.5
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• pp.375-380
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• 2011

This study investigated the effects of inorganic sulfur on metastasis in MDA-MB-231 human breast cancer cells. MDA-MB-231 cells were cultured in the absence or presence of various concentrations (12.5, 25, or 50 ${\mu}mol$/L) of inorganic sulfur. Cell motility, invasion, and the activity and mRNA expression of matrix metalloproteases (MMPs) were examined. Numbers of viable MDA-MB-231 cells did not differ by inorganic sulfur treatment from 0 to 50 ${\mu}mol$/L within 48 h. Inorganic sulfur significantly decreased cell motility and invasion in the MDA-MB-231 cells in a dose-dependent manner (P<0.05), as determined using a Boyden chamber assay and a Matrigel chamber. The activities of MMP-2 and MMP-9 were significantly reduced by inorganic sulfur in a dose-dependent manner (P<0.05). The inorganic sulfur also significantly inhibited MMP-2 and MMP-9 expression in the cells (P<0.05). These data suggest that inorganic sulfur can suppress cancer cell motility and invasion by inhibiting MMP-2 and MMP-9 activity and gene expression in MDA-MB-231 cells.

• Structural Engineering and Mechanics
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• v.87 no.4
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• pp.375-389
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• 2023

In many fiber concrete beams with Carbon Fiber Reinforced Polymer (CFRP), debonding occurs between the carbon sheets and the concrete due to the low strength of the bonding resin. A total of 42 fiber concrete beams with a cross-section of 10×10 cm with a span length of 50 cm are fabricated and retrofitted with CFRP and subjected to a 4-point bending test. Graphene Oxide (GO) at 1, 2, and 3 wt% of the resin is used to improve the mechanical properties of the bonding resins, and the effect of length, width, and the number of layers of CFRP and resin material are investigated. The crack pattern, failure mode, and stress-strain curve are analyzed and compared in each case. The results showed that adding GO to polyamine resin could improve the bonding between the resin and the fiber concrete beam. Furthermore, the optimum amount of nanomaterials is equal to 2% by the weight of the resin. Using 2% nanomaterials showed that by increasing the length, width, and number of layers, the bearing and stiffness of fiber concrete beams increased significantly.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.199-211
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• 2021

This study analyzed the factors that influence the domestic SMEs that have introduced smart factories on their intention to accept at a higher level for qualitative advancement. 375 copies collected through an online survey were analyzed using SPSS and AMOS with UTAUT and the extended two-stage information system continuous model. Performance expectancy, effort expectancy, social influence, and facilitating conditions have a statistically significant effect on user satisfaction and user satisfaction and CEO's will have an effect on the intention to accept the advancement. However, the suppliers' technology didn't have a direct effect on the advancement acceptance intention and user satisfaction has a mediating effect between performance expectancy, effort expectancy, social influence, facilitating conditions and the advancement acceptance intention. SME's advancement for smart factory, it is important to improve the satisfaction level and the CEO's will to become smart.