• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.244.1-244.1
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• 2008

• Journal of the Korean Physical Society
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• v.80
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• pp.1-12
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• 2022

Over the past few decades, tetrafluoroethane (TFE, R134a Freon)-based gases have been widely used in the operation of phenolic resistive plate chambers (RPCs) in many high-energy experiments. However, TFE has a high global warming potential (GWP); therefore, a search for new eco-friendly gases to replace traditional TFE-based ones is now unavoidable. In this research, we present cosmic-ray test results of a prototype RPC for the SHiP (search for hidden particles) experiment using 1.6- and 1.4-mm-thick RPC electrodes containing mixtures of various gases, including 1,3,3,3-tetrafluoropropene (HFO1234ze), CO₂, iC₄H₁₀ and SF₆. We compare the performance data gathered with these new gas mixtures with those gathered with a traditional TFE-based gas used for RPCs in compact muon solenoid (CMS) and a toroidal LHC apparatus (ATLAS) experiments. The addition of CO₂ to the HFO1234ze-based gas was found to be fairly effective in reducing the working-point high voltage (HVWP) for RPC operation. The results of our experiments lead us to the conclusion that adding 40% CO₂ or less, when combined with HFO1234ze-based gas, is conducive to reliable detector performance for SHiP single-gap phenolic RPCs.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2298-2304
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• 2023

Titanium alloys are expected to become one of the candidate materials for nuclear-powered spacecraft due to their excellent overall performance. Nevertheless, atomistic mechanisms of the defect accumulation and evolution of the materials due to long-term exposure to irradiation remain scarcely understood by far. Here we investigate the heavy irradiation damage in a-titanium with a dose as high as 4.0 canonical displacements per atom (cDPA) using atomistic simulations of Frenkel pair accumulation. Results show that the content of surviving defects increases sharply before 0.04 cDPA and then decreases slowly to stabilize, exhibiting a strong correlation with the system energy. Under the current simulation conditions, the defect clustering fraction may be not directly dependent on the irradiation dose. Compared to vacancies, interstitials are more likely to form clusters, which may further cause the formation of 1/3<1210> interstitial-type dislocation loops extended along the (1010) plane. This study provides an important insight into the understanding of the irradiation damage behaviors for titanium.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.156.1-156.1
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.46-46
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• 2008

• Journal of The Korean Association For Science Education
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• v.10 no.1
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• pp.57-64
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• 1990

In this study, novices' protocols were investigated on the basis of Mayer's analysis of mathematical problem solving. These protocols were obtained by Jae-Sool Kwon and Seong-Wang Lee(1988) by means of thinking aloud while 20 sophomore students in a department of physics education were solving physics problems on Newton's low of motion. The results of investiqation are as follows; (1) We proposed an effective method in analyzing protocols on physics porblem solving (2) We could find the defective types of knowledge of individuals who got an incorrect solution, through analyzing the cause of failure individually (3) The fact that many students considered first the frictional force as muntiplying the coefficient of friction by perpendicular force rather than as resistance of motion, was found And students' misconception on the coefficient of friction was found. (4) If such analyses of test items and protocols are used in physics education, they will be very useful for finding the faults of problem-solving process, and for setting and scoring subjective problems in physics

• Journal of Engineering Education Research
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• v.22 no.4
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• pp.22-31
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• 2019

This study aims to elucidate the relationship between physics and mathematics to predict achievement for the college level of engineering courses. For the last 4 years, more than 3,000 engineering college freshmen of this study took the diagnostic tests on three subjects, which were physics, mathematics, and chemistry before enrollment. We studied how strongly these diagnostic scores can predict each general college course grades. The correlation between the physics diagnostic scores and the course grades in physics was .264, which was significantly lower than the correlation between the mathematics scores and the physics grades, .311. This stronger prediction of the mathematical diagnostic scores for the general course grades was not found when predicting the grades in chemistry. We therefore conclude that mathematical preparation can unexpectedly predict future achievement in physics better than physics preparation due to the academic interrelationships between mathematics and physics.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.42.2-42.2
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• 2008

• Proceedings of the Korean Vacuum Society Conference
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• 2006.08a
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• pp.91-91
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• 2006

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.129.1-129.1
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• 2007