• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.165-173
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• 2016

On March 11, 2011, a massive earthquake measuring 9.0 on the Richter scale and subsequent 10-.14 m waves struck the Fukushima Daiichi (FD) Nuclear Power Plant. The main and backup electric power was damaged preventing the cooling system from functioning. Fuel rods overheated and led to hydrogen explosions. If heat in the fuel rods is not dissipated, the nuclear fuel coating material (e.g., Zircaloy) reacts with water vapor to generate hydrogen at high temperatures. This hydrogen is released into the containment area. If the released hydrogen burns, the stability of the containment area is significantly impacted. In this study, researchers performed an explosion analysis in a high-risk explosion area, analyzing the hydrogen distribution in a containment building [1] and the effects of a hydrogen explosion on containment safety. Results indicated that a hydrogen explosion was possible throughout the containment building except the middle area. If an explosion occurs at the top of the containment building with more than 40% of the hydrogen collected or in the bottom right or left side of the of containment building, safety of the containment building could be threatened.

• Journal of the Korea Institute of Building Construction
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• v.14 no.4
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• pp.285-291
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• 2014

Partial replacement of cement with blast furnace slag has many advantages such as the reduction of construction fee, the decrease of hydration heat and the increase of long-term strength. Hence, slag is widely used in practice. This study investigates the effect of slag on the rheological properties of cement paste and mortar. Three different types of slag (BS1, BS2 and BS3) with five different contents (0, 20, 40, 60 and 80 wt.%) were used to replace the cement. Each type of slag has different fineness. Water to binder ratio was 0.5. Test results showed that the partial replacement of BS1 and BS2 decreased flow and increased O-lot flow time, whereas that of BS3 caused an opposite effect, i.e., increased flow and decreased O-lot flow time. It was found that there was a good corelation between the values of yield stress and flow.

• Journal of the Korean Society of Safety
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• v.35 no.3
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• pp.96-104
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• 2020

The numerical simulations were conducted to investigate the thermal-fluid phenomena occurred inside the experimental apparatus during a PCCS, used to remove heat released in accidents from a containment of light water nuclear power plant, operation. Numerical simulations of the flow and heat transfer caused by wall condensation inside the containment simulation vessel (CSV), which equipped with 18 vertical heat exchanger tubes, were conducted using the commercial computational fluid dynamics (CFD) software ANSYS-CFX. Shear stress transport (SST) and the wall condensation model were used for turbulence closure and wall condensation, respectively. The simulation using the actual size of the apparatus. However, rather than simulating the whole experimental apparatus in consideration of the experimental cases, calculation resources, and calculation time, the simulation model was prepared only in CSV. Selective simulation was conducted to verify the effects of non-condensable gas(NC gas) concentration, CSV internal pressure, and wall sub-cooling conditions. First, as a result of the internal flow of CSV, it was observed that downward flow due to condensation occurred surface of the vertical tube and upward flow occurred in the distant place. Natural convection occurred actively around the heat exchanger tube. Due to this rising and falling internal flow, natural circulation occurred actively around the heat exchanger tubes. Next, in order to check the performance of built-in condensation model using according to the non-condensable gas concentration, CSV internal flow and wall sub-cooling, the heat flux values were compared with the experimental results. On average, the results were underestimated with and error of about 25%. In addition, the influence of CSV internal pressure and wall sub-cooling was small, but when the condensate was highly generated due to the low non-condensable gas concentration, the error was large compared to the experimental values. This is considered to be due to the nature of the condensation model of the CFX code. However, in spite of the limitations of CFD, it is valid to use the built-in condensation model of CFD for PCCS performance prediction from a conservative perspective.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.4
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• pp.418-428
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• 2017

In offshore area, newly deposited Quaternary loose seabed soils are widely distributed. There are a great number of offshore structures has been built on them in the past, or will be built on them in the future due to the fact that there would be no very dense seabed soil foundation could be chosen at planed sites sometimes. However, loosely deposited seabed foundation would bring great risk to the service ability of offshore structures after construction. Currently, the understanding on wave-induced liquefaction mechanism in loose seabed foundation has been greatly improved; however, the recognition on the consolidation characteristics and settlement estimation of loose seabed foundation under offshore structures is still limited. In this study, taking a semi-coupled numerical model FSSI-CAS 2D as the tool, the consolidation and settlement of loosely deposited sandy seabed foundation under an offshore breakwater is investigated. The advanced soil constitutive model Pastor-Zienkiewics Mark III (PZIII) is used to describe the quasi-static behavior of loose sandy seabed soil. The computational results show that PZIII model is capable of being used for settlement estimation problem of loosely deposited sandy seabed foundation. For loose sandy seabed foundation, elastic deformation is the dominant component in consolidation process. It is suggested that general elastic model is acceptable for subsidence estimation of offshore structures on loose seabed foundation; however, Young's modulus E must be dependent on the confining effective stress, rather than a constant in computation.

• KIEAE Journal
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• v.15 no.1
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• pp.139-146
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• 2015

This is an experimental study on the engineering characteristics of perforated reinforced concrete beams with shells. In the material matter of this study, the water cement ratio put 60%, the ratio of substitution of oyster shells to fine aggregate 30%. And in the structural matter, the form of opening put circle and square, the size of opening as the radius and the length of it changed from one to three times of the beam depth with a change presence and absence of reinforced steel around opening. All thirteen reinforced concrete beam tests composed one standard beam and twelve six beams with the circle and square opening were tested in shear strength under two points loading and compared and analyzed the characteristics of test beams under the same conditions one another. The results of the study showed as followed. 1) The initial crack load value of the opening test beams is similar the standard beam but the maximum load value decreased with increase in proportion of the opening size, in the square opening than the circle opening and in the absence than the presence of reinforced steel. 2) As the difference between the circle opening and the square opening beams is represented 2.17~9.8% in the maximum load value and the load capacity of the square opening suddenly decrease than it of the circle opening, it is judged because of the shortage of concrete section, the concentration of the stress in the corner of the square opening and material influence of shell substitution. 3) The failure figure such as the pattern of the crack and so on is represented brittle failure as the opening size is the bigger and the ratio of substitution is higher because of the lack material properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.159-159
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• 2015

A new approach for antimicrobial is based on the overproduction of reactive nitrogen species (RNS), especially; nitric oxide (NO) and peroxinitrite (ONOO-) are important factors to deactivate the bacteria. Recently, non-thermal atmospheric pressure plasma jet (APPJ) has been frequently used in the field of microbial sterilization through the generation of different kinds of RNS/ROS species. However, in previous study we showed APPJ has combine effects ROS/RNS on bacterial sterilization. It is not still clear whether this bacterial killing effect has been done through ROS or RNS. We need to further investigate separate effect of ROS and RNS on bacterial sterilization. Hence, in this work, we have enhanced NO production, especially; by applying a 1% of HNO3 vapour to the N2 based APPJ. In comparison with nitrogen plasma with inclusion of water vapour plasma, it has been shown that nitrogen plasma with inclusion of 1% of HNO3 vapour has higher efficiency in killing the E. coli through the high production of NO. We also investigate the enhancement of NO species both in atmosphere by emission spectrum and inside the solution by ultraviolet absorption spectroscopy. Moreover, qPCR analysis of oxidative stress mRNA shows higher gene expression. It is noted that 1% of HNO3 vapour plasma generates high amount of NO for killing bacteria.

• Korean Journal of Medicinal Crop Science
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• v.17 no.4
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• pp.266-272
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• 2009

Cinnamyl alcohol dehydrogenase (CAD, EC 1.1.1.95), catalyzes the reduction of hydroxycinnamaldehydes to give hydroxycinnamyl alcohols, or "monolignols," the monomeric precursors of lignin. Lignins are important components of cell walls and lignified secondary cell walls play crucial roles in long distance transport of water and nutrients during plant growth and development and in plant defense against biotic and abiotic stresses. Here a cDNA clone containing a CAD gene, named as PgCAD, was isolated from a commercial medicinal plant Panax ginseng. PgCAD is predicted to encode a precursor protein of 177 amino acid residues, and its sequence shares high homology with a number of other plant CADS. The expression of PgCAD in adventitious roots and hairy roots of P. ginseng was analyzed using reverse transcriptase (RT)-PCR under various abiotic stresses such as salt, salicylic acid, wounding and chilling treatment that triggered a significant induction of PgCAD at different time points within 2-48 h post-treatment. This study revealed that PgCAD may help the plants to survive against various abiotic stresses.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.4
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• pp.92-104
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• 2002

This study investigates, analyzes, and summarizes Dansplantation techniques and methods through practical methodology centering on fieldwork in order to present effective planting methods for large trees that have important significance. The conclusions are as follows : 1. The transplantation process of a large tree generally consists of the stages of digging up a tree, manufacturing a carrier frame, loading the tee on a vehicle, transporting, transplanting the tree, installing a strut and maintaining and managing the new transplant. In addition, planting a tree on a mounted place includes the primary procedures of trimming out the root, and preparing for transplanting the tree on a mounted place, as well as the secondary work of trimming out the root, transplanting a tree on a mounted place, maintenance and management. 2. In order to decide on a transplantation method for a large-sized tree, a structure calculation has to be performed first. That is, one must calculate the weight of the tree and the allowable stress of the strut (H-beam, etc.) fhst and then decide on the upper method through computer modeling based upon this structural calculation. 3. As a result of the analysis of a transplanted tree using the life soil method, it was confirmed that large quantities of feeder roots had developed around the root within a short time after the transplantation. The life soil method has proven to be very effective for transplantation of large-sized trees. 4. As for the production method of an H-beam strut frame, it was found that the manufacturing process and disassembly process were simple and proper; therefore, the H-beam frame is an appropriate structure to be used in the transplantation of large trees. 5. The concavo-convex method, which consists of filling the life soil in the concavo-convex area around the root, was found to be a method that promotes the growth of feeder roots within a short period of time and saves the supply of water at the same time.

• Journal of Nutrition and Health
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• v.38 no.2
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• pp.125-143
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• 2005

The purposes of this study were to investigate the characteristics of lifestyle and dietary habits of the colorectal cancer patients in Daegu and Kyungpook areas and to collect the data useful for nutrition education for the prevention of colorectal cancer in this community. The case subjects of the study were 123 patients diagnosed recently as colorectal cancer at Kyungpook National University Hospital. The control subjects were 182 persons who did not have any gastrointestinal diseases, including the patients from the department of orthopedic surgery and healthy volunteers. The survey covering general characteristics, life style, dietary habits, eating behaviors, and food intake frequency was administered by individual interviews using questionnaires. The results of the study suggest that high BMI, daily life stress, pessimistic personality, lack of physical activities, and familial cancer history might be the possible risk factors for the incidence of colorectal cancer. Dietary factors suspected as risk factors for colorectal cancer in the present study included strong preferences to meats, salty and fatty taste foods, low intake of water, alcohol drinking, smoking, coffee intake and irregular eating habits. A high consumption of seaweeds, green-yellow vegetables, light-colored vegetables, and green tea was suggested as a preventive factor for colorectal cancer. It is recommended to conduct more extensive and systematic surveys in the near future to reconfirm the risk factors of colorectal cancer in consideration of the characteristic food culture in this community. The results of the present study may be applied to nutritional education for the prevention of colorectal cancer for the local residents. (Korean J Nutrition 38(2): 125～143, 2005)

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.77.1-77
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• 2003

We have isolated a full-length cDNA clone, CaCDPK4 encoding a typical calcium-dependent protein kinase (CDPK) from hot pepper cDNA library. Genomic southern blot analysis showed that it belongs to a multigene family, but represents a single copy gone in hot pepper genome. RNA expression pattern of this gene revealed that it is induced by infiltration of Xanthomonas axonopodis pv. glycines Bra into hot pepper leaves but not by water deficit stress. However, high salt treatment of NaCl (0.4 M) solution to hot pepper plants strongly induced CaCDPK4 gene. In addition, this gene is weakly responsive to the exogenous application of salicylic acid or ethephon. Biochemical study of the GST-CaCDPK4 recominant protein showed that it autophosphorylates in vitro and the presence of EGTA, a calcium chelater, eliminates the kinase activity of the recombinant protein. As a way to identify the in vivo function of CaCDPK4 in plants, VIGS (Virus-Induced Gene Silencing) was employed. Agrobacterium-mediated TRV silencing construct containing the kinase and calmodulin domain of CaCDPK4 resulted in cell death of Nicotiana benthamiana plants. A highly homologous H benthamiana CDPK gene, NbCDPK5, to CaCDPK4 was cloned from N. benthamiana cDNA library. VIGS of NbCDPK5 also resulted in cell death. The molecular characterization of this cell death phenotype is being under investigation.