• Nuclear Engineering and Technology
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• v.56 no.10
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• pp.4404-4411
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• 2024

The dissolved oxygen in a coolant can affect the oxidation properties of structural materials. A desirable oxide phase formation is achieved by manipulating the oxygen level in the coolant, which can mitigate structural material degradation in nuclear power plants. Therefore, the role of dissolved oxygen in the corrosion of structural materials in aqueous environments needs to be understood. In this study, a short-term corrosion test (up to 300 h) of Ferritic/Martensitic steels (F/M steels; FeCrW model alloys), namely, Fe12Cr1W, Fe9Cr1W, and Fe9Cr, in stagnant water at 360 ℃ was performed in a pressurized autoclave with the dissolved oxygen concentration controlled to 1 ppm or a very low level (<1 ppm). The results of the corrosion tests showed that an increase in the oxygen level in the water elevated the corrosion potential, allowing the phase transition of iron oxide from magnetite (Fe₃O₄) to hematite (Fe₂O₃), whereas there was no significant correlation between the concentrations of the alloying elements Cr and W and the oxide growth rate. In addition, hematite was found to mitigate further oxide growth. Finally, a mechanism for the growth of the initial oxide layer was proposed based on the experimental results.

• Corrosion Science and Technology
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• v.8 no.2
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• pp.89-92
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• 2009

Pure Ti as well as Ti-6Al-4V alloy exhibit excellent properties for dental implant applications. However, for a better biocompatibility it seems important to avoid in the composition the presence of V due to the toxic effects of V ion release. Thus Al and V free and composed of non-toxic element such as Nb, Zr alloys as biomaterials have been developed. Especially, Zr contains to same family in periodic table as Ti. The addition of Zr to Ti alloy has an excellent mechanical properties, good corrosion resistance, and biocompatibility. In this study, the electrochemical characteristics of Ti-Zr alloys for biomaterials have been investigated using by electrochemical methods. Methods: Ti-Zr(10, 20, 30 and 40 wt%) alloys were prepared by arc melting and homogenized for 24 hr at $1000^{\circ}C$ in argon atmosphere. Phase constitutions and microstructure of the specimens were characterized by XRD, OM and SEM. The corrosion properties of the specimens were examined through potentiodynamic test (potential range of -1500 ~ 2000 mV), potentiostatic test (const. potential of 300 mV) in artificial saliva solution by potentiostat (EG&G Co, PARSTAT 2273. USA).

• Food Science of Animal Resources
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• v.29 no.4
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• pp.423-429
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• 2009

The objective of this study was to investigate the potential of the application of lactic acid bacteria (LAB) from kimchi as a starter culture in the production of fermented sausages. To achieve this, a submerged model medium that contained LAB as part of a complex system of kimchi (0.5, 1.0, 1.0, 3.0, and 5.0%) and lyophilized kimchi powder (0.2 and 0.5%) was fermented for 120 h. During the fermentation period, the growth of total viable organisms and LAB, and the changes in the pH and the titratable acidity, were investigated. The initial LAB counts ranged from 6.4 to 7.7 Log CFU/mL for the kimchi media, and from 6.9 to 6.9 Log CFU/mL for the kimchi powder media. In all the kimchi batches, the LAB increased logarithmically, and the highest LAB counts (around 9 Log CFU/mL) were reached in 24 h. An evident lag phase of the LAB was observed in the kimchi powder samples and reached 8.8 Log CFU/mL in 8 h. The decrease in the pH and the formation of lactic acid were rapid in the kimchi batches, and reached pH values of 3.4-3.5 in 12 h. With these results, the LAB that was integrated with the addition of kimchi or kimchi powder demonstrated its potential utility as a substitute for starter culture.

• Journal of KIISE:Software and Applications
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• v.26 no.1
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• pp.157-157
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• 1999

Researches on the gesture recognition have become a very interesting topic in the computer vision area, Gesture recognition from visual images has a number of potential applicationssuch as HCI (Human Computer Interaction), VR(Virtual Reality), machine vision. To overcome thetechnical barriers in visual processing, conventional approaches have employed cumbersome devicessuch as datagloves or color marked gloves. In this research, we capture gesture images without usingexternal devices and generate a gesture trajectery composed of point-tokens. The trajectory Is spottedusing phase-based velocity constraints and recognized using the discrete left-right HMM. Inputvectors to the HMM are obtained by using the LBG clustering algorithm on a polar-coordinate spacewhere point-tokens on the Cartesian space .are converted. A gesture vocabulary is composed oftwenty-two dynamic hand gestures for editing drawing elements. In our experiment, one hundred dataper gesture are collected from twenty persons, Fifty data are used for training and another fifty datafor recognition experiment. The recognition result shows about 95% recognition rate and also thepossibility that these results can be applied to several potential systems operated by gestures. Thedeveloped system is running in real time for editing basic graphic primitives in the hardwareenvironments of a Pentium-pro (200 MHz), a Matrox Meteor graphic board and a CCD camera, anda Window95 and Visual C++ software environment.

• International Journal of Automotive Technology
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• v.7 no.7
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• pp.867-872
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• 2006

Fuel cells are devices that convert chemical energy directly into electrical energy. Owing to the high efficiency of the fuel cells, a large number of research work have been done during these years. Among many kinds of the fuel cells, a polymer electrolyte membrane fuel cell is such kind of thing which works under low temperature. Because of the specialty, it stimulated intense global R&D competition. Most of the major world automakers are racing to develop polymer electrolyte membrane fuel cell passenger vehicles. Unfortunately, there are still many problems to be solved in order to make them into the commercial use, such as the thermal and water management in working process of PEMFCs. To solve the difficulites facing the researcher, the analysis of the inner mechanism of PEMFC should be implemented as much as possible and mathematical modeling is an important tool for the research of the fuel cell especially with the combination of experiment. By regarding some of the assumptions and simplifications, using the finite element technique, a two-dimensional electrochemical mode is presented in this paper for the further comparison with experimental data. Based on the principals of the problem, the equations of electronic charge conservation equation, gas-phase continuity equation, and mass balance equation are used in calculating. Finally, modeling results indicate some of the phenomenon in a unit cell, and the relationships between potential and current density.

• Korean Journal of Pharmacognosy
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• v.45 no.4
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• pp.326-331
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• 2014

In this study, we investigated pharmacologic activity of rice bran ethyl acetate fraction (RBE), based on their osteoblast enhancing effects. It has been found that REB have a stimulatory effect on the commitment of bi-potential mesenchymal precursor C2C12 cells into osteoblasts in the presence of BMP-2. Furthermore, RBE enhanced the BMP-2-stimulated induction of ALP, an early phase biomarker of osteoblast differentiation. In addition, Western blot analysis showed RBE enhanced the BMP-2-stimulated phosphorylation of p38, but not those of ERK or JNK. These findings show RBE has the potential to enhance the BMP-2-mediated commitment of C2C12 cells into osteoblasts and their differentiation through p38 activation.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.10a
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• pp.95-98
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• 2000

The rapid expansion of the WWW is well known and has huge potential for enabling companies, large and small, to gain new marketplaces globally at low cost, or to be disintermediated by others doing so. A totally new competitive environment opening up new opportunities is upon us. As a result, the electronic commerce is growing quickly and the importance of electronic marketplace is emphasized. From the view of SCM, applying the business-to-business electronic commerce to the relationship between firms is expected to make major changes. This study focuses on the effects of the introduction of web-based purchasing systems on the buyer-supplier relationship. We conduct a case study on the Korean firms The major findings of this study are summarized as follows. First, in introductory phase, some buying firms fail to design the appropriate mechanism for business relationships. It can weaken the cooperation between buyers and suppliers. Second, for critical or customized parts, it is possible to gather the information about potential suppliers and to make business relations using it. Third, using web-based purchasing systems, capable suppliers can take more opportunities to leverage its competence for business relations. So we can expect the positive feedback.

• Korean Institute of Interior Design Journal
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• v.16 no.2 s.61
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• pp.71-78
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• 2007

This study began from the idea that new materials and awareness in the modern society demand new methods in architecture and focused on diagrams as the tool many modern architects use in their process of architectural design. Therefore, the purpose is re-finding the potential of diagrams as profilerating architectural design media by examining mentions of architects about diagrams, investigating diagrams used in design process and treating comments referring to diagrams, by redefining the meaning of the contemporary architecture and of diagrams in architecture, and by grasping the various methods of use and its process. The design process using diagrams produces synthetic or reasonable process dissimilar to previous processes. Where diagrams are mainly used as tools to relate the segregated parts compressively. On the other hand reasonable process concerns reasonable design advancement to satisfy various requirements or conditions in reality, where diagrams are used as tools offering its phase in the whole structure of various information and relating steps of design each other. Dealing synthetically in the various steps of design process with the various properties originally obtained, proposing a new type of architecture by increasing thoughts and leaving the design process open-fluid, offering process and results having the same value as design process, and satisfying requirements in reality most reasonably, diagrams working in the above-mentioned design process have the potential to narrow the schism among theory, practice and criticism in contemporary architecture.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.181-187
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• 2004

With the proliferation of nonlinear loads, high neutral harmonic currents in three-phase four-wire distribution system have been observed. It has been known that the ground impedance has an effect on the neutral currents of a system which operates with harmonics present. On-site measurements of harmonic currents and voltages according to the fall-of-potential method under case study system were made and the ground impedance modeling using the pattern search method for the harmonic analysis was developed The ground impedance model obtained by the proposed method was compared with the frequency characteristics by field tests and has shown appropriate results, and would be applicable to evaluate the harmonic and transient response characteristics of the ground system.

• Journal of Powder Materials
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• v.16 no.3
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• pp.217-222
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• 2009

This paper presents a novel single-step method to prepare the Ag nanometallic particle dispersed fluid (nanofluid) by electrical explosion of wire in liquid, deionized water (DI water). X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) were used to investigate the characteristics of the Ag nanofluids. Zeta potential was also used to measure the dispersion properties of the as-prepared Ag nanofluid. Pure Ag phase was detected in the nanofluids using water. FE-SEM analysis shows that the size of the particles formed in DI water was about 88 nm and Zeta potential value was about -43.68 without any physical and chemical treatments. Thermal conductivity of the as-prepared Ag particle dispersed nanofluid shows much higher value than that of pure DI water.