• 한국세라믹학회지
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• 제49권4호
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• pp.287-294
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• 2012

Ceramic Matrix Composites (CMCs) represent a class of non-brittle refractory materials for harsh and extreme environments in aerospace and other applications. The quasi-ductility of these structural materials depends on the quality of the interface between the matrix and the fiber surface. In this study, a manufacture route is described where in contrast to most other processes no additional fiber coating is used to adjust the fiber/matrix interfaces in order to obtain damage tolerance and fracture toughness. Adapted microstructures of uncoated carbon fiber preforms were developed to permit the rapid infiltration of molten alloys and the subsequent reaction with the carbon matrix. Furthermore, any direct reaction between the melt and fibers was minimized. Using pure silicon as the reactive melt, C/SiC composites were manufactured with an aim of employing the resulting composite for friction applications. This paper describes the formation of the microstructure inside the C/C preform and resulting C/C-SiC composite, in addition to the MAX phases.

• 센서학회지
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• 제24권3호
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• pp.159-164
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• 2015

Solid state electrochemical and chemo-resistive gas sensors have been used widely but can operate only under high temperature. For reducing the power consumption and optimizing the structure of the substrate of these sensors, we conducted device and circuit simulations using the COMSOL Multiphysics simulator. For assessing the effective types of substrate and heat isolation, we conducted three-dimensional thermal simulations in two separate parts; (a) by changing the shape of the contacting holes and (b) punching additional holes on the substrate. Thus, it was possible to achieve high temperature in the sensor end of the substrate while maintaining low power consumption, and temperature in the circuit.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.339-342
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• 2000

This paper presented a FPGA design of SEED, which is the Korea standard 128-bit block cipher. In this work, SEED was designed technology- independently for other applications such as ASIC or core-based designs. Hence in case of changing the target of design, it is not necessary to modify design or need only minor modification to reuse the design. Since SEED algorithm requires a lot of hardware resources, each unit was designed only once and used sequentially. So, the number of gates was minimized and SEED algorithm was fitted in FPGA without additional components. It was confirmed that the rate of resource usage is about 80% in ALTERA 10KE and the SEED design operates in a clock frequency of 131.57 MHz and an encryption rate of 29 Mbps.

• Transactions on Electrical and Electronic Materials
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• 제12권1호
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• pp.1-6
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• 2011

This paper summarized concept, manufacture and results of the micro-tubular solid oxide fuel cells (SOFCs). The cells were fabricated by co-sintering of extruded micro-tubular anode support and electrolyte coating layer, and then additional cathode coating. The cells showed quick voltage rising within 1 minute, and the electrochemical performances were closely related to the balance of fuel utilization and performance loss. And a thermal-fluid simulation model was also reported in combination with the electrochemical evaluation results on the GDC-based micro-tubular SOFCs.

• Nuclear Engineering and Technology
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• 제45권3호
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• pp.311-322
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• 2013

High-Cr martensitic steel HT-9 is one of the candidate materials for advanced nuclear energy systems. Thanks to its excellent thermal conductivity and irradiation resistance, ferritic/martensitic steels such as HT-9 are considered for in-core applications of advanced nuclear reactors. The harsh neutron irradiation environments at the reactor core region pose a unique challenge for structural and cladding materials. Microstructural and microchemical changes resulting from displacement damage are anticipated for structural materials after prolonged neutron exposure. Consequently, various irradiation effects on the service performance of in-core materials need to be understood. In this work, the fundamentals of radiation damage and irradiation effects of the HT-9 martensitic steel are reviewed. The objective of this paper is to provide a background introduction of displacement damage, microstructural evolution, and subsequent effects on mechanical properties of the HT-9 martensitic steel under neutron irradiations. Mechanical test results of the irradiated HT-9 steel obtained from previous fast reactor and fusion programs are summarized along with the information of irradiated microstructure. This review can serve as a starting point for additional investigations on the in-core applications of ferritic/martensitic steels in advanced nuclear reactors.

• 무역상무연구
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• 제72권
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• pp.115-137
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• 2016

Trade can be greatly influenced by the change of international trade environment due to the characteristics of remote transactions. Furthermore, in the circumstance of emphasizing the national security again, the importance of the risk management of special materials has been increasing. As it was noted at Chapter 4, significant results such as the threat of enterprises' sustainable growth can be occurred when companies are related to the unlawful export of strategic materials or experience discouragement of export of main products. As the decision of strategic materials greatly depend on a specialized knowledge there is a possibility of misjudgement of strategic materials in terms of ordinary companies which is not accustomed to them. Furthermore risk management is more difficult due to the inclusion to the items of export license. To prepare such a risk of export of strategic materials, firstly, it should be checked to find whether counter traders are working in the industry which is not related to the spread of weapons of mass destruction, secondly, an appropriate process shall be designed and operated for products to be safely delivered to the trade counter. Therefore, our export enterprises have to introduce CP(Compliance Program), AEO or ISO28000 considering suitability for their actual situations not only to promote export and but also to avoid risk of export control and additional expenses. Through these appropriate processes, an efficient and effective management of the trade risk of strategic materials can be accomplished.

• 한국의학물리학회지:의학물리
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• 제31권2호
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• pp.29-34
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• 2020

Purpose: The interaction of various substances inserted into the human body and radiation can confirm the radiation enhancement effect. A Leksell frame inserted into the human body for gamma knife treatment will cause not only pain and inconvenience to the patient, but also additional exposure to the patient's normal tissues. In this study, we attempt to confirm the additional exposure caused by the interaction of the Leksell frame and thermoplastic mask, and ⁶⁰Co used for gamma knife treatment. Methods: A ⁶⁰Co energy of 1.17, 1.33 MeV is applied using Monte Carlo simulation, and fixation screws and thermoplastic mask are fabricated using aluminum and titanium alloy, and Carbon compounds. Results: Results show a dose enhancement of up to 396.27% higher compared with that without a Leksell frame and up to 391.25% in thermoplastic mask. Conclusions: Hence, appropriate treatment methods and materials must be used to reduce additional exposure to normal tissues.

• 한국수산과학회지
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• 제18권5호
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• pp.424-432
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• 1985

명태냉동고기풀을 사용하여 어묵을 가공할 때 각종 부원료의 최적첨가량을 예측할 수 있는 방안을 강구하기 위하여 옥수수전분, 분리대두단백질 및 중합인산염을 첨가하여 이들이 어묵의 탄력에 미치는 영향을 검토하였다. Instron texturometer를 사용하여 얻어진 6가지 파라미터 중에서 젤리강도와 가장 상관성이 높은 것은 hardness였으며, 관능검사결과 hardness의 값이 증가함에 따라 품질이 향상되었으나, hardness값이 16kg 이상에서는 오히려 품질이 저하하였다. 옥수수전분, 분리대두단백질 및 중합인산염의 첨가에 따른 hardness의 예측식은 각각 H=11.56+0.54Xcs, H=12.22-0.23Xsp, H=11.65-7.13Xpp였다. 옥수수전분과 분리대두단백질, 중합인산염과 옥수수전분 및 중합인산염과 분리대두단백질을 각각 혼합첨가 하였을 때 hardness의 예측식은 각각 H=11.57+0.53Xcs+0.44Xsp, H=11.97-1.83Xpp-0.17Xcs, H=11.58+0.08Xpp-0.23Xsp였다.

• 한국재료학회지
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• 제28권3호
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• pp.135-141
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• 2018

Stainless steel is being used in various industries such as automobile and aerospace for its cheap manufacturing cost and excellent mechanical properties. However, stainless steel failed to stably protect a specimen with a $Cr_2O_3$ protective layer at temperatures above $1000^{\circ}C$. Thus, improving the high temperature flame resistance of the specimen through additional surface coating was needed. In this study, multilayer coatings of YSZ and $Al_2O_3$ were performed on SUS 304 specimens using pack cementation coatings and thermal plasma spray. The multilayer coated specimen showed enhanced thermal properties due to the coated layers. The microstructures and phase stability are discussed together with flame conditions at $1350^{\circ}C$.

• 한국주거학회논문집
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• 제25권2호
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• pp.121-130
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• 2014

This paper provides a social knowledge for pragmatic application guidelines of the interior finish materials within apartment houses, based on both the awareness of practitioners and as it applies to the realities. For this purpose, a series of the questionnaires survey on the awareness of interior finish materials in recently-constructed and remodeled apartment houses was performed, which has extended its probe into the awareness of architectural practitioners. The questionnaires asked practitioners how much they desire sustainable finish materials and the difference in various parties were analyzed and compared, formulating the pragmatic solution in the determination of interior finishes. Comparative analysis of the awareness of construction specialists, interior designer, architectural environmental researchers on environment-friendly finish materials showed that all parties were right to recognize the significance of sustainability in interior finishes. Practitioners believed that occupants must bear the additional expense for the environment-friendly finish products. Also, the results tell that the amount used of environment-friendly products increases as expertise on sustainability in interior finishes rises.