• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1184-1186
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• 2009

• Bulletin of the Korean Chemical Society
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• v.29 no.11
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• pp.2247-2251
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• 2008

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2048-2054
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• 2022

The coolant temperature feedback coefficient is an important parameter of reactor core power control system. To study the coolant temperature feedback coefficient influence on the core power control system of small PWR, the core power control system is built with the nonlinear model and fuzzy control theory. Then, the uncertainty quantification method of reactor core parameters is established based on the Latin hypercube sampling method and the Bootstrap method. Finally, under the conditions of reactivity step perturbation and coolant inlet temperature step perturbation, uncertainty analysis for two cases is carried out. The result shows that with fuzzy controller and fuzzy PID controller, the uncertainty of the coolant temperature feedback coefficient affects the core power control system, and the maximum uncertainties of core relative power, coolant temperature deviation, fuel temperature deviation and total reactivity are acceptable.

• Proceedings of the Korean Society of Life Science Conference
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• 2005.04a
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• pp.202-202
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• 2005

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.999-1008
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• 2023

Deformed fuel rods can cause a partial blockage of the flow area in a subchannel. Such flow blockage will influence the core coolant flow and further the core heat transfer during the reflooding phase and subsequent severe accidents. Nevertheless, most of the system analysis codes simulate the accident process based on the assumed flow blockage ratio, resulting in inconsistencies between simulated results and actual conditions. This paper aims to study the influence of flow blockage in severe accident scenario of the CAP1400 reactor. First, the flow blockage model of ISAA code is improved based on the FRTMB module. Then, the ISAA-FRTMB coupling system is adopted to model and calculate the QUENCH-LOCA-0 experiment. The correctness and validity of the flow blockage model are verified by comparing the peak cladding temperature. Finally, the DVI Line-SBLOCA accident is induced to analyze the influence of flow blockage on subsequent CAP1400 reactor core heat transfer and core degradation. From the results of the DVI Line-SBLOCA accident analysis, it can be concluded that the blockage ratio is in the range of 40%-60%, and the position of severe blockage is the same as that of cladding rupture. The blockage reduces the circulation area of the core coolant, which in turn impacts the heat exchange between the core and the coolant, leading to the early failure and collapse of some core assemblies and accelerating the core degradation process.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3848-3851
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• 2010

• The Journal of Advanced Prosthodontics
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• v.7 no.5
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• pp.349-357
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• 2015

PURPOSE. The purpose of this study was to assess the impact of the core materials, thickness and fabrication methods of veneering porcelain on prosthesis fracture in the porcelain fused to metal and the porcelain veneered zirconia. MATERIALS AND METHODS. Forty nickel-chrome alloy cores and 40 zirconia cores were made. Half of each core group was 0.5 mm-in thickness and the other half was 1.0 mm-in thickness. Thus, there were four groups with 20 cores/group. Each group was divided into two subgroups with two different veneering methods (conventional powder/liquid layering technique and the heat-pressing technique). Tensile strength was measured using the biaxial flexural strength test based on the ISO standard 6872:2008 and Weibull analysis was conducted. Factors influencing fracture strength were analyzed through three-way ANOVA (${\alpha}{\leq}.05$) and the influence of core thickness and veneering method in each core materials was assessed using two-way ANOVA (${\alpha}{\leq}.05$). RESULTS. The biaxial flexural strength test showed that the fabrication method of veneering porcelain has the largest impact on the fracture strength followed by the core thickness and the core material. In the metal groups, both the core thickness and the fabrication method of the veneering porcelain significantly influenced on the fracture strength, while only the fabrication method affected the fracture strength in the zirconia groups. CONCLUSION. The fabrication method is more influential to the strength of a prosthesis compared to the core character determined by material and thickness of the core.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2535-2538
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• 2012

$SnO_2@carbon$ tube-core nanowire was synthesized via a facile self-organized method, which was in situ by one step via Chemical Vapor Deposition. The resulting composite was characterized by scanning electron microscopy, X-ray diffraction and transmission electron microscope. The diameter of the single nanowire is between 5 nm and 60 nm, while the length would be several tens to hundreds of micrometers. Then X-ray diffraction pattern shows that the composition is amorphous carbon and tin dioxide. Transmission electron microscope images indicate that the nanowire consists of two parts, the outer carbon tube and the inner tin dioxide core. Meanwhile, the possible growth mechanism of $SnO_2@carbon$ tube-core nanowire is also discussed.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.851-859
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• 2021

Small PWR can be used for power generation and heating. Considering that small PWR has the characteristics of flexible operating conditions and complex operating environment, the controller designed based on single power level is difficult to achieve the ideal control of small PWR in the whole range of core power range. To solve this problem, a flexible switching controller based on fuzzy controller and LQG/LTR controller is designed. Firstly, a core fuzzy multi-model suitable for full power range is established. Then, T-S fuzzy rules are designed to realize the flexible switching between fuzzy controller and LQG/LTR controller. Finally, based on the core power feedback principle, the core flexible switching control system of small PWR is established and simulated. The results show that the flexible switching controller can effectively control the core power of small PWR and the control effect has the advantages of both fuzzy controller and LQG/LTR controller.

• Journal of the Korean Society of Earth Science Education
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• v.6 no.2
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• pp.112-123
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• 2013

Under this research, the survey is made on the definitive influence of the first-year education process of the science focus school for each of humanities, science and science core courses and the level of satisfaction of the non-curriculum experiment activity program for each course to find out the effectiveness of the first-year education process of the science focus school. For this purpose, this research has set three research issues. First, By clarifying the research result through the first-year education curriculum for science core school, noticeable change was observed for science focus school students through the change of attitude related to science for each desired course of students. Second, in the self-directed learning characteristics change, there was meaningful change for each desired field of students. Students hoping for humanities curriculum had great help in improvement of creative thinking for openness, creativeness and the like, but the influence was slightly insufficient in the moderation and control capability on themselves in learning attitude. Third, By analyzing the research result comprehensively, the first-year education curriculum for science core school provides high level of tailored science learning for the science focus school students and the level of satisfaction for students was significantly high.