• Nuclear Engineering and Technology
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• v.35 no.4
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• pp.299-308
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• 2003

Fabrication technique of $(Th,U)O_2$ pellets has been investigated. Powder mixtures of $ThO_2\;and\;UO_2$ were milled in two different ways-dry and wet milling. Milled powder was compacted and sintered to $(Th,U)O_2$ pellets. The wet-milled powder leads to a $(Th,U)O_2$ pellet having a high sintered density and uniform distribution of U and Th, compared to the dry-milled powder. The sintered density of a $(Th,U)O_2$ pellet tends to decrease by increasing the content of $ThO_2$. The thermal conductivity of $ThO_2\;and\;(Th,U)O_2$ pellets was measured by the laser flash method. The thermal conductivity of the $ThO_2$ pellet is higher than that of the $UO_2$ pellet, and the thermal conductivities of $(Th,U)O_2$ pellets containing $65wt\%\;and\;35wt\%\;ThO_2$ pellets are lower than that of the $UO_2$ pellet.

• Korean Journal of Materials Research
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• v.3 no.3
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• pp.245-252
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• 1993

We investigated the changes of (U, Ce)$O_2$ powder characteristics with $CeO_2$ contents and ball-milling time and then studied on the sintering properties with those (U, Ce)$O_2$ powder characteristics. From the results of this study, it was concluded that the longer ball-milling time of (U, Ce)$O_2$ powder was, the finer its particle size was. Green and sintered densities were decreased with $CeO_2$ contensts increase. And also $CeO_2$ was recongized deteriorating oxide on the $UO_2$ sintering. In case of the lOwt. % $CeO_2$ contents, (U, Ce)$O_2$ sintered pellet which was made of ball-milled powder for 4 hours had few pores and its pores got near to the sphere. And its sintered density had the highest. Because its powder had higher surface area and its packing ratio was appropriated much better than others.

• Electronics and Telecommunications Trends
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• v.20 no.2 s.92
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• pp.93-102
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• 2005

유비쿼터스 코리아(u-Korea) 기본전략에 따르면 우리나라는 정치. 사회. 문화. 의료. 복지. 교육. 노동. 외교 등 사회 전반에 걸친 생활문화 혁명이 실현될 것으로 전망된다. 이러한 시점에서 정보보호는 u-Korea 실현의 중요한 핵심 엔진 기술로써u-Korea 전략 추진의 주요한 장애 요인으로 예상되는 사생활 문제와 지역 간. 계층간 정보격차 문제 등의 정보화 역기능을 해소하는 역할을 수행해야 한다. 본 고에서는 정통부가 추진하고자 하는 u-Korea 기본 전략에 대해서 살펴보고, 안전한 u-Korea 실현을 위해서 구체적인 정보화 역기능 방지 대책을 제안한다. 특히, BcN 인프라 보호 기술, RFID/USN 개인 프라이버시 보호 기술, WiBro 및 DMB 등에서 사용되는 복합단말기용 통합 인증. 인가 기술, 안전한 사용자 서비스 제공을 위한 서비스 사용의 익명성과 서비스 관리의 실명성이 제공되는 보안위임서비스 기술 등으로 형성되는 “Security Belt” 정보화 역기능 방지 대책에 대해서 소개한다.

• The Journal of the Korea Contents Association
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• v.6 no.9
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• pp.67-74
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• 2006

Resently, We suggested u-Korea strategy to manage and develop a nation based on national ubiquitous technology using mobile.. therefore many a local self-governing body is writing out u-City construction plan to build most suitable future city in oneself environment. In this paper, after analyze tendency and character of ubiquitous related plans, it makes a plan international youth digital film festival based on ubiquitous technology in jinju. And it suggest strategy of digital film or game industry on a department of digital contents industry. also, an opportunity this paper propose research scheme of early level for u-Jinju of city-farm composition supported ubiquitous service in all the jinju area.

• Nuclear Engineering and Technology
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• v.40 no.5
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• pp.409-418
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• 2008

Because the interaction layers that form between U-Mo particles and the Al matrix degrade the thermal properties of U-Mo/Al dispersion fuel, an investigation was undertaken of the undesirable feedback effect between an interaction layer growth and a centerline temperature increase for dispersion fuel. The radial temperature distribution due to interaction layer growth during irradiation was calculated iteratively in relation to changes in the volume fractions, the thermal conductivities of the constituents, and the oxide thickness with the burnup. The interaction layer growth, which is estimated on the basis of the temperature calculations, showed a reasonable agreement with the post-irradiation examination results of the U-Mo/Al dispersion fuel rods irradiated at the HANARO reactor. The U-Mo particle size was found to be a dominant factor that determined the fuel temperature during irradiation. Dispersion fuel with larger U-Mo particles revealed lower levels of both the interaction layer formation and the fuel temperature increase. The results confirm that the use of large U-Mo particles appears to be an effective way of mitigating the thermal degradation of U-Mo/Al dispersion fuel.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.6
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• pp.1447-1452
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• 2010

Ubiquitous society to build basic infrastructure in the power supply and power equipment safety is important. u-City in order to prevent the disaster of u-IT Power Equipment Performance Module and the security for the safety of the u-City is necessary. In this paper, the power unit of u-IT module, temperature sensor, humidity sensor, equipped with sensors arranged throughout the fire, and home distribution boards, Home Network Wall-Pad, Blocker, MPNP black boxes, arc detection, arc safety equipment, outlet of the modular performance evaluation methods and security methods will be studied. u-IT power devices and sensors to analyze the information conveyed by proactive risk and ensure safety, access control, authentication, security safeguards, such as u-IT integrated management system for electrical safety and strengthen the security, safety and security with a u-City will contribute to the construction and operation.

• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.85-93
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• 2010

The goal of U-Eco City testbed is improving the technical completion of ubiquitous technology/Services which have been developed in other core projects in U-Eco City, by implementing newly developed ubiquitous technology/Services to testbed. When the newly developed ubiquitous technology/Services are implemented in the testbed, we will monitor whether the developed ubiquitous technology/Services can be applied in the real situation and if they have problems we will find out the solution to solve the problems. Final goal of this reaserch is framework development for the U-Eco City construction guideline. We developed the framework development for the U-Eco City construction guideline by i)analyzing steps for construction of U-Eco City, ii) analyzing details of each steps for construction of U-Eco City, and iii) including results of research which have been developed in other core projects in U-Eco City.

• Journal of Korea Spatial Information System Society
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• v.11 no.1
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• pp.145-156
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• 2009

Ubiquitous City(U-City) in Korea is not a fantastic wonderland but an on-going real phenomenon. Many researchers so far have mainly dealt with a rosy future where U-City would potentially promise the high Quality of Life and positive economic effects. However, a suspicion of unexpected disadvantages can be able to take place in the bright future of U-City : the running cost of U-City. Without full consideration of it, descendants living in the U-City in near future will suffer from the heavy burden in operating the U-City. Given this circumstantial background, the aim of this study is to indicate potential solutions to address a sustainable U-City controlled by the virtuous cycled mechanism toward a self-sufficient city, which will illuminate a new paradigm of the city history. Solutions were sought from the several viewpoints, which were behavioral and institutional aspects, developing profitable business models and core technologies applicable to U-City, and building self-owned networks. Based on this preliminary study, further efforts and devotion to seeking virtuous-cycled U-City model will contribute to bringing a prominent future of U-City whose belongings will be able to manage to enjoy better quality of life.

• Korea Multimedia Society
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• v.10 no.1
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• pp.149-162
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• 2006

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.148-156
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• 2001

We report $^{230}Th/^{234}U$ disequilibrium ages of fracture-filling carbonate veins from the Ipsil and Janghangri fault zones, Gyeongju, Korea by multiple collector inductively coupled plasma mass spectrometry. The U and Th fraction was extracted from totally dissolved samples by rapid and convenient coprecipitation and ion exchange chemistry. The recovery was around 80% for Th and 70% for U. The $^{234}U/^{238}U,\;^{230}Th/^{232}Th$ ratios were analysed for this preconcentrated fraction and the U/Th ratio was directly analysed for untreated sample solution. The $^{234}U-^{230}Th$ system is in secular equilibrium for the Ipsil carbonate samples, supporting previously reported ESR ages. The detrital-corrected $^{230}Th/^{234}U$ age of the Janghangri carbonate samples is $48\pm$41 ka, which constrains the minimum age of the fracture zone.