• Title/Summary/Keyword: 자기학

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Displacement sensor for Measuring magnetostriction of Amorphous Ribbon (비정질 리본의 자기변형 측정용 광섬유 변위센서)

  • 유권상;김철기;김중복;김현아
    • Journal of the Korean Magnetics Society
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    • v.6 no.1
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    • pp.36-39
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    • 1996
  • We have constructed a disp1acerrent sensor for measuring dynamic magnetostriction of an arrvrphous ribbon under alternating magnetic field using fiber optic Fabry-Perot interferorreter. The signal of the sensor was depen¬dent on the index matching oil and the optical isolator. The resolution of the sensor was $30{\AA}$ and the measured peak to peak magnetostriction of the amorphous ribbon $Fe_{81}B_{13.5}Si_{3.5}C_{2}$ was $28{\times}10^{-6}$.

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Measurement of AC Hysteresis Loops under Variable Tensile Stress for Amorphous Wire (비정질 세선의 인장응력에 따른 교류자기이력 특성측정)

  • 조희정;양종만;손대락;김구영
    • Journal of the Korean Magnetics Society
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    • v.3 no.1
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    • pp.61-64
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    • 1993
  • We have constructed a hysteresis loop tracer in order to measure the magnetic properties of amorphous wires under variable tensile stress. It has a force range of 0 N to 20 N and a magnetizing frequency of 1 kHz to 20 kHz. Using the ac-hysteresis loop tracer, we can measure the magnetic properties(maximum magnetic induction $B_{max}$, residual magnetic induction $B_{r}$, coercive field strength $H_{c}$, etc.) of amorphous wires with precision of 1% under variable tensile stresses.

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Precise Measurement of Magnetic Field Using CW-NMR Technique (CW-NMR 기법을 이용한 자기장 정밀측정)

  • 이정한;이대행;김민철;이순칠;홍계원;이호준
    • Journal of the Korean Magnetics Society
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    • v.5 no.1
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    • pp.79-85
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    • 1995
  • A precise magnetic field probe was designed to measure the field distribution inside a superconducting magnet. The operation principle of the developed equipment is based on cw-NMR. The range of field is from 2.8 T to 5.8 T, and the resolution is better than 0.3 ppm NMR samples were water and heavy water contained in a tube of 4 mm diameter and 4mm height. This equipment can be manufactured very inexpensively compared with the currently available commertial ones.

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Substrate-induced Magnetic Anisotropy and GMR Effects in Cu/Co Multilayers (Cu/CO 다층 박막에서의 거대 자기 저항과 자기 비등방성)

  • Park, C.M.
    • Journal of the Korean Magnetics Society
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    • v.13 no.6
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    • pp.243-245
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    • 2003
  • The anomalous angular modulation of magnetoresistance in Co/Cu multilayers is explained assuming substrate-induced magnetic anisotropy. The magnetic parameters of Co/Cu multilayers is determined using angular modulation of magnetoresistance and theoretical model including substrate-induced anisotropy. This mechanism introduces a new possible way of modulating the giant magnetoresistance.

The Effects of Ar Gas Pressure on Thin Films Prepared by dc Magnetron Sputtering (DC 마그네트론 스퍼터링으로 제작된 NiFe 박막에서 Ar 압력이 자기 및 자기저항 성질에 미치는 영향)

  • 민병철;신성철
    • Journal of the Korean Magnetics Society
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    • v.6 no.2
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    • pp.98-105
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    • 1996
  • 스퍼터링 방법으로 제작된 NiFe 박막에서 Ar 압력이 자기 및 자기저항 성질에 미치는 여향을 조사하였다. 타겟으로는 Ni$_{81}$$Fe_{19}$ 조성의 합금타겟을 사용하였다. TEM을 써서 박막의 미세구조를 조사하였으며, 보자력과 포화자화는 VSM으로 측정하였다. 합금박막의 조성은 ICPS로 분석 확인하였다. 10 mTorr 이상의 높은 Ar 압력에서 제작된 박막에서 갈라진 틈새(crack-like void)를 갖는 주상구조가 관찰되었다. 이러한 주상 결정립경계(columnar grain boundary)가 자화 과정에서 자구벽 핀닝자리(pinning site)가 되어, Ar 압력이 커짐에 따라 보자력이 증가 하였으며, 박막의 밀도가 감소하여 포화자화가 줄어드는 것을 볼 수 있었다. 한편, Ar 압력이 증가하면서 자기저항비가 감소하는 결과를 얻었다. 결정립 경계 산란과 결정립간 터널링에 의한 박막의 비저항의 증가가 이러한 자기저항비 감소의 주원인임을 알 수 있었다.다.

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사출성형에 의한 이방성 Nd-Fe-B계 레진본드자석의 자기적 특성

  • 김윤배;정우상;정원용
    • Journal of the Korean Magnetics Society
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    • v.9 no.2
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    • pp.71-77
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    • 1999
  • 본 연구에서는 이방성 Nd-Fe-B계 자성분말과 바인더로 polypropylene을 사용하여 compound를 제조한 후 사출성형에 의해 이방성 Nd-Fe-B 레진본드자석을 제조하여 자성분말의 함량, 인가자장 및 사출성형 온도에 따른 자기적 특성 및 유변학적 특성을 조사하였다. Torque sensor에 의해 측정한 본 연구에 사용된 이방상 Nd-Fe-B계 자성분말의 최대 분말함량은 70.7vol%이었다. Compound의 자성분말 함량이 증가함에 따라 레진본드자석의 잔류자속밀도와 최대자기에너지적은 증가하여 54vol%에서 최대값을 보인후 다시 감소하였고, 보자력은 변화가 없었다. 54vol% 자성분말 함량 이상에서 잔류자속밀도와 최대자기에너지적이 다시 감소하는 것은 사출성형시 자성분말의 배향도 저하에 기인한다. 이것은 compound의 자성분말 함량이 증가함에 따라 compound의 유동성이 저하되어 사출성형시 자성분말의 이방화를 어렵게 만들기 때문이다. 사출성형 온도가 증가함에 따라 레진본드자석의 자기적 특성은 증가하였다. 이는 성형온도가 증가함에 따라 compound의 유동성이 향상되어 자성분말의 배향도가 증가되었기 때문이다. 따라서 사출성형에 의해 이방성 Nd-Fe-B계 레진본드자석 제조시 자기적 특성을 향상시키기 위해서는 compound의 자성말 함량 뿐만 아니라 compound의 유동성이 중요하게 고려되어야 한다.

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Exploring the Dimensions of Self Efficacy Scale for Information Literacy (정보문해 자기효능감 척도의 적용을 위한 탐색적 연구)

  • Shim, Won-Sik;Ahn, Hye-Yeon;Kim, Hyun-Soo;Kim, Sung-Hwan
    • Journal of the Korean Society for Library and Information Science
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    • v.43 no.4
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    • pp.307-326
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    • 2009
  • The concept of self efficacy, originally theorized by Bandura, has been applied to a wide variety of fields including education, psychology, and business. There has been steady effort to develop relevant scales to operationalize and measure self efficacy. This article reports on the results from an analysis of Kurbanoglu's ILSES (Information Literacy Self-Efficacy Scale), the only reported such scale in the area of information literacy. Over 400 university students responded to the ILSES survey consisting of 40 items grouped in six categories. The main analysis used was factor analysis. The results show high degree of internal consistency of the items included. However, the factors derived from the study differ significantly from the factors in the original study. Overall, these factors seem to reflect the heuristic nature of students' information seeking and use patterns, favoring Internet resources and instant gratification.

The Effects of Faculty-Student Interaction and Peer Relations upon Academic Self-efficacy of dental hygiene students (치위생(학)과 학생의 교수-학생 상호작용과 교우관계가 학업적 자기효능감에 미치는 영향)

  • Cheon, Hye Won;Jun, Mee-Jin
    • Journal of Convergence for Information Technology
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    • v.9 no.11
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    • pp.159-170
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    • 2019
  • This study examined the influence of academic self-efficacy of Faculty-student inter action and peer relations. The subject were collected from 289 dental hygiene students J region, three colleges of between November 5, December 30, in 2018. The data was analyzed by descriptive, pearson correlation coefficient and multiple regression. Faculty-student interact ion was correlated with peer relations(r=.434) and had a positively correlation with academic self-efficacy(r=.282) with improved of major satisfaction and higher academic performance, a much more vigorous active faculty-student interaction and peer relations of level of academic self-efficacy. The results reveals to develop program co-relationship in order to improve academic self-efficacy.

Effect of Career Stress on Career Preparation Behavior: Sequential Mediating Effects of Career Decision Self-efficacy and Career Motivation (진로스트레스가 진로준비행동에 미치는 영향: 진로결정 자기효능감 및 진로동기의 순차적 매개 효과)

  • Hye-Ran Lee;Hyun Kim;Byung-Hwan Hyun
    • Industry Promotion Research
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    • v.9 no.3
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    • pp.241-249
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    • 2024
  • The purpose of this study was to investigate the individual variables that influence the behavior of college students who successfully set career goals, plan for achieving goals, and specifically practice them. As a result of analyzing the relationship between career stress, career decision-making self-efficacy, career motivation, and career preparation behavior through a survey of 300 four-year college students nationwide, career stress negatively affected career self-efficacy, career decision-making self-efficacy had a positive effect on career motivation, and career motivation had a positive effect on career preparation behavior. In addition, career decision-making self-efficacy and career motivation sequentially mediated between career stress and career preparation behavior. It is significant that college students found personal variables necessary to successfully prepare for career and confirmed the relationship between the variables through the results of this study.

Effect of Clinical Practice on Self-Learning Development Ability (임상실습이 자기학습 발전능력에 미치는 영향)

  • Kim, Jung-Hyun;Kim, Nak-Sang;Yang, Han-Joon
    • Journal of radiological science and technology
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    • v.40 no.3
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    • pp.493-499
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    • 2017
  • In order to analyze the degree of self-learning development ability after the clinical training curriculum, the results of 121 questionnaires were analyzed for 3rd and 4th grade students in radiology in the metropolitan area. The overall average of self-learning ability according to gender was $3.07{\pm}0.85$, which was statistically significant according to gender. However, the results according to educational system showed that the overall average was $3.07{\pm}0.85$, which was higher than the average level of self-learning development ability. There was no statistically significant difference according to educational system. The results of the self-learning development ability according to the motivation for selecting the department showed that the students who have chosen their department due to their higher employment rate after graduation had high self-development ability level($3.58{\pm}0.85$) but the students who entered the school due to self-aptitude had relatively lower self-development ability level ($2.30{\pm}0.40$). The overall average of self-learning ability according to direction of career path was $3.08{\pm}0.76$, which was over-average of self-learning development ability. Thus, there was statistically significant difference according to career path. It is necessary to improve the self-learning ability in clinical practice. In addition, the lack of statistical significance suggests problems and diversity.