• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11b
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• pp.329-337
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• 2005

Synroc which comprises hollandite-rich ($Ba_{1-x}Cs_{2x}\;(Al_yTi_{2-y})\;Ti_{6}O_{16},\;75wt\%$), perovskite ($Ca_{1-x}Sr_xTiO_3,\;15wt\%$) and rutile ($TiO_2,\;10wt\%$) is devised for the immobilization of Sr/Cs (1:3, wt$\%$) separated from HLW liquid. Especially, hollandite-rich Synroc with different contents of Al element is fabricated, and its mineral phase assemblage and microstructure are determined by using XRD and SEM/EDS. The durability test is carried out by using MCC-1 method, leachate is analyzed by using ICP/MS and ICP/ AES. The results indicate that hollandite-rich Synroc variants is a suitable host for Immobilization of Sr/Cs separated from HLW liquid.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.837-840
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• 2002

An analysis method for rubber toughened PVC is suggested to evaluate critical dynamic strain energy release rates($G_c$) from the Charpy impact energy measurements. An instrumented Charpy impact tester was used to extract ancillary information concerning fracture parameters in addition to total fracture energies and maximum critical loads. The dynamic stress intensity factor $K_{Id}$ was computed for varying amounts of rubber contents from the obtained maximum critical loads and also toughening effects were investigated as well. The fracture surfaces produced under low velocity impact fur PVC/MBS composites were investigated by SEM. The results show that MBS rubber is very effective reinforcement material for toughening PVC.C.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.955-956
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• 2006

Fe-doped $TiO_2$ nanopowders were prepared by mechanical alloying (MA) varying Fe contents up to 8.0 wt.%. The UV-vis absorption showed that the UV absorption for the Fe-doped powder shifted to a longer wavelength (red shift). The absorption threshold depends on the concentration of nano-size Fe dopant. As the Fe concentration increased up to 4 wt.%, the UV-vis absorption and the magnetization were increased. The benefical effect of Fe doping for photocatalysis and ferromagnetism had the critical dopant concentration of 4 wt.%. Based on the UV absorption and magnetization, the dopant level is localized to the valence band of $TiO_2$.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.1
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• pp.62-65
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• 2015

Wireless Sensor Network consists of several sensor nodes, these nodes loss some of their energy after the process of communication. So an energy efficient approach is required to improve the life of the network. In case of broadcast network, LEACH protocol uses an aggregative approach by creating cluster of nodes. Now the major concern is to built such clusters over WSN in an optimized way. This work presents the improvement over LEACH protocol. Hence we have different work environments where the network is having different capacities. The proposed work shows how the life time of the network will improve when the number of nodes varies within the network.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.3
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• pp.79-89
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• 2011

Since commercial operation of Kori-1 nuclear power plant in 1978, twenty units are under operation and six units are under construction at 2011 present. Nuclear power become a main energy source in our country. However, the plant was constructed by a USA vendor in its beginning period, the Quality Assurance requirements of USA was applied. Even though Quality Assurance requirements were newly established to the Korea Atomic Energy Act, its contents are quite similar to those of USA. And 10 CFR 50 App.B, ASME NQA-1 apply to most of nuclear industries as a quality assurance plan. In this paper, Quality Assurance requirement of domestic nuclear industries has been investigated and applicable method of ISO Quality Assurance application to the nuclear industries is suggested by a comparison ISO 9000 and nuclear quality assurance specification.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.52.2-52.2
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• 2018

The shape of a galaxy's spectral energy distribution ranging from ultraviolet (UV) to infrared (IR) wavelengths provides crucial information about the underlying stellar populations, metal contents, and star-formation history. Therefore, analysis of the SED is the main means through which astronomers study distant galaxies. However, interstellar dust absorbs and scatters UV and optical light, re-emitting the absorbed energy in the mid-IR and Far-IR. I present the updated 3D Monte-Carlo radaitive transfer code MoCafe to compute the radiative transfer of stellar, dust emission through a dusty medium. The code calculates the emission expected from dust not only in pure thermal equilibrium state but also in non-thermal equilibrium state. The stochastic heating of very small dust grains and/or PAHs is calculated by solving the transition probability matrix equation between different vibrational, internal energy states. The calculation of stochastic heating is computationally expensive. A pilot study of radiative transfer models of SEDs in clumpy (turbulent), galactic environments, which has been successfully used to understand the Calzetti attenuation curves in Seon & Draine (2016), is also presented.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.159-164
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• 1997

Pyrolytic carbon layer was coated on A1203 balls by fluidized bed type chemical vapour deposition unit to develop the coating technology for the preparation of coated nuclear fuel. The deposition was carried out at the temperature ranges between 110$0^{\circ}C$ and 130$0^{\circ}C$ with various gas contents and flow rates. Source and carrier gas were propane and argon, respectively. X-ray analysis shows that the deposition layer was typical carbon spectra. The growth rate of carbon layer depended on the amount of source gas and the deposition temperature. For the alumina balls with 2mm in diameter, the deposition rate was 11${\mu}{\textrm}{m}$/hr in the flow gases containing 30% source gas at 130$0^{\circ}C$ with a total flow rate of 2.0$\ell$/min. Microstructural observation of the deposits with scanning electron microscope revealed that the deposits had relatively dense and isotropic structure. Chemical analysis by energy dispersive spectroscopy showed that the layer was pure carbon.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.65-75
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• 2018

The wind energy produced at night is being discarded because of the excess power generated at night compared to daytime. To solve this problem, In this study, we analyzed the evaluation contents for evaluation of domestic and overseas water electrolysis systems and drew contents for safety performance contents test of the water electrolysis system based on the evaluation contents. The test contents produced the efficiency measurement test, the hydrogen generated pressure test, and the hydrogen purity test. And the safety performance evaluation of the alkaline water electrolysis system of $5Nm^3/hr$ was performed based on the results. As a result, the hydrogen generation was calculated as $5.10Nm^3/hr$ and the stack efficiency was $4.97kWh/Nm^3$. The purity of the hydrogen generated was 99.993% and it was confirmed that it produced high purity hydrogen. I think will help us assess and build safety performance of water electrolysis systems in the future.

• Journal of the Korean Society of Earth Science Education
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• v.7 no.1
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• pp.119-132
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• 2014

In recent years, Korea encourages teachers to do STEAM education(Science, Technology, Engineering, Arts & Mathematics), which includes Arts to STEM education to train creative science technology talent. Related to this, we developed a subject substitute STEAM program for the 6th grade students in elementary school and applied it in a field. The STEAM program which substitutes contents in curriculum related to Energy unit was developed and it was taught to twenty four sixth grade students during regular classes. During the classes, all activities of students were observed and they were written in recording notes during the observation. After all STEAM program ended, how students recognize the subject substitute STEAM program compared to general class, understand learning contents and think about the program before and after the STEAM classes were analyzed through questionnaire and interviews. The results were as follows. First, some students had difficulty in reconciling different ideas in group, creative thinking and crafts but most students liked the STEAM classes because many activities are fun and it is easy to understand. Second, learners regarded practical use of knowledge, learning different subjects together and interests as the reasons they can understand learning contents easily during STEAM program. Third, learners recognized STEAM classes are good to understand knowledge, think creative ideas and improve social skills after the STEAM classes while they showed anticipation, worry and fear before taking the classes. It is found that a subjective substitute STEAM program is helpful to increase learners' interests in learning, understand learning contents, increase creativity and have a good personality through a qualitative research.

• Journal of Nutrition and Health
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• v.26 no.1
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• pp.21-33
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• 1993

This balance study was performed to investigate nutritional effects of guar gum and calcium supplement for 8 weeks. 36 male rate of Sprague-Dawley strain weighing 50g were blocked into six groups : 5CN, 5GN, 5CS, 5GS, FFN, 10GN. Food intake, body weight gains, FER, PER, bioavailabity of energy, protein, fat, Ca and P, and Ca & P content of femur and kidney was measured. The results obtained in this study were summarized as follows: (1) Feed intake, weight gains, FER, PER and bioavailabilities of protein and P and the contents of Ca & P in femur of 5GB were significantly higher than 5CN and 5CS (p<0.05) but was not significant different with those 5GN. Fat bioavailabilities of 5GS was significantly lower than 5CN and 5GN (p<0.05) but was not significant different with those of 5CS. Ca contents of kidney of 5GS was significantly higher than 5CN and 5GN(p<0.05) but was not significant different with those of 5SC. (2) According to guar gum levels feed intake. FER and PER were not sifgnificantly different among groups but body weight gains, bioavailabilities of energy, protein, fat and Ca, Ca & P content of femur was significantly decreased (p<0.05). Bioavailabilities of P was significantly increased according to the guar gum levels (p<0.05). Ca contents in Kidney of 10GN was significantly higher those of 5GN(p<0.05) but P contents in kidney was not significant difference by guar gum levels. Therefore 5% supplemental guar gum in diet of obese man and diebetics could be recommended. But it should be careful in using 10% guar gum in diet.