• Title/Summary/Keyword: 자기상

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First-principles Calculations on Magnetism of 1H/1T Boundary in Monolayer MoS2 (제일원리계산에 의한 단층 MoS2의 1H/1T 경계 자성)

  • Jekal, Soyoung;Hong, Soon Cheol
    • Journal of the Korean Magnetics Society
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    • v.26 no.3
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    • pp.71-75
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    • 2016

  • Monolayer $MoS_2$ is energetically most stable when it has a 1H phase, but 1H to 1T phase transition ($1H{\rightarrow}1T$) is easily realized by various ways. Even though magnetic moment is not observed during $1H{\rightarrow}1T$, $0.049{\mu}_B/MoS_2$ is obtained in local 1T phase; 75% 2H and 25% 1T phases are mixed in ($2{\times}2$) supercell. Most magnetic moment is originated from the 1T phase Mo atom in the supercell, while the magnetic moments of other atoms are negligible. As a result, magnetic/non-magnetic boundary is created in the monolayered $MoS_2$. Our result suggests that $MoS_2$ can be applied for spintronics such as a spin transistor.

  • https://doi.org/10.4283/JKMS.2016.26.3.071 인용 PDF KSCI

Significance of Ultrasonography in Diagnosis of Medial Meniscus Tear (내측 반월상 연골 파열의 진단에서 초음파의 의의)

  • Kim, Jung-Man;Im, Dong-Sun;Kim, Tae-Hyung;Kim, Jong-Ick;Lee, Kyu-Jo
    • The Journal of Korean Orthopaedic Ultrasound Society
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    • v.4 no.1
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    • pp.1-6
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    • 2011

  • Purpose: To evaluate the usefulness of ultrasonography in diagnosis of the medial meniscus tear as a screening tool before performing magnetic resonance imaging. Materials and Methods: From April 2009 to September 2010, magnetic resonance imaging (MRI) was taken in 147 knees out of 341 knees examined with ultrasonography (US) under the suspicion of medial meniscus tear. The sonographic findings were 16 without abnormality, 12 inhomogeneity, 4 cluster, 60 cleavage and 55 more than 5mm medial extrusion of medial meniscus. In Statistical analysis, sensitivity and specificity, positive predictive value and negative predictive values were calculated. Results: The MRI showed abnormality in 104 knees. Sensitivity and specificity of ultrasonography for MRI was 94.2% and 23.3%, respectively. Positive predictive value was 74.8%, negative predictive value was 62.5%. The positive predictive value of ultrasonography were 58.3% in heterogeneity, 100% in showing cluster, 75% in visible cleft and 80% in medial extrusion. Conclusion: The US is a useful tool in prediction of medial meniscus tear before confirming it in high-cost MRI.

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A Study on the Differences of Problem-Solving Ability between Students with High Level of Self-efficacy and Students with Low Level of Self-efficacy (PBL 수업에서 공과대학 학생들의 자기효능감 수준에 따른 문제해결 능력 차이)

  • Shin, Min-Hee
    • Journal of Engineering Education Research
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    • v.12 no.4
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    • pp.30-37
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    • 2009

  • The purpose of this study was to examine the difference of problem-solving ability according to student's level of self-efficacy. Participants were 72 junior students who took the course 'Environmental Instrumental Analysis'. Before the PBL activities, students were given the self-efficacy tests to all students. Among them, 44 students(30% of each high and low ranking) were selected and encouraged to complete pre-problem solving tests. The PBL was conducted for 12 weeks using blended learning strategies. After the PBL, 44students completed post-problem solving tests. Results showed that there were differences of problem-solving ability according to student's level of self-efficacy. From the results, instructional strategies for promoting students' self-efficacy should be employed for enhancing problem-solving ability in PBL activities.

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