• Journal of Magnetics
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• 제19권3호
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• pp.205-209
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• 2014

$MnBi_{1-x}Ti_x$ (x = 0, 0.4, 0.7, 1) alloys were prepared by arc-melting, followed by heat treatment. X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) were used to measure and investigate the phase structure and magnetic properties. The temperature dependent magnetization curves indicate that the phase transitions between LTP and HTP MnBi occur with heating or cooling in $MnBi_{1-x}Ti_x$ ($x{\leq}0.7$) samples. However, MnTi samples are in $Mn_2Ti$ single-phase, with very low magnetic properties. Furthermore, the coercivity exhibits a positive temperature coefficient. The results show that the optimal content of Ti for the coercivity of $MnBi_{1-x}Ti_x$ alloy is x = 0.4. For MnBi sample, the coercivity reaches a maximum value of 1.13 T at 550 K. However, the remanence and energy product show apparent decrease with the addition of Ti in $MnBi_{1-x}Ti_x$ alloys.

• 한국초등과학교육학회지:초등과학교육
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• 제24권5호특별호
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• pp.620-626
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• 2005

In this study, we conducted a comparative study to investigate the curriculums on electricity and magnetism between in Korean and in Ontario elementary schools in Canada with respect to connectivity and difference among course materials with grades. We compared textbooks that contain the contents about electricity and magnetism, and connectivity in curriculums that were relevant to the science content system in each country. We report the following differences in the curriculums on electricity and magnetism in each country. First, it turns out that science is taught from the first grade in Ontario, while it is taught from the third grade in Korea. Second, Ontario covers electricity and magnetism only in science curriculum, while Korea covers the same topics both in the science and practical arts curriculum. Third, while the curriculum in Korea introduces 'a magnet' in the third grade, 'electricity' in the fourth and the fifth grade, and 'an electromagnet' in the sixth grade, while the curriculum in Ontario covers the concept of energy from the first grade. As the grades go up, the contents of electricity and magnetism tend to be more deepen. It also emphasizes enhancing students' ability that they can communicate what they learn about technology with others, and that they can apply their knowledge to other fields as well. Based on this study of the Ontario curriculum, we suggest that it is necessary for us to n Science curriculum from the first grade, so that the students can learn science from the early grade, without a need to run another subject, like practical arts. We also found that the Korean curriculum has an interesting structure for the young students to learn to apply their knowledge to the real life immediately, based on an idea that the topic of 'Manipulating the electric appliances' in practical arts curriculum moves to the Science.

• 한국자기학회지
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• 제22권4호
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• pp.142-146
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• 2012

자석에 대한 인간의 관심은 긴 역사를 가지고 있으며, 또한 자석을 바라보는 시선도 다양했다. 과거에는 과학자의 시선이 아니라 철학자의 눈으로 바라다 보기도 하였다. 이 글에서는 과거 우리나라에서 자석을 어떻게 인식해왔는가를 다루어보고자 한다. 자석과 관련된 내용을 시기적으로 분류해 보면 1) 자성(磁性)의 인식기 2) 극성(極性)의 인식기 3) 근대지식의 유입기로 나눌 수 있다. 한국사 전체에서 보면, 신라에서 자석을 생산하였다는 기록을 찾을 수 있었으며 고려시대 기록에서는 자석에 관한 자료를 찾을 수 없었다. 자석에 대한 관심은 조선시대에 들어와서 고조된 것으로 보인다. 그 중에서도 풍수 즉 양택과 음택의 입지와 관련하여 가장 많이 이용되었다. 조선시대에는 항해에 자석을 사용하였다는 기록도 확인된다. 그밖에 의외의 사용처로는 약재의 일부로 쓴 경우를 볼 수 있다.

• 한국환경복원기술학회지
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• 제8권5호
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• pp.19-27
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• 2005

The earth is a huge magnet. All organisms live under the magnetism of earth. The magnetism influences the ions in the cells of organisms and variously functions to lives as well. The medical treatment with magnet has come down from the ancient, it has an effect on the plants' growth. But there are no scientific studies about the influences of magnetism on plant growth. Accordingly, the experiment about the influence of magnetism on several foliage plants was carried out in this study. The promotion of plants' growth led by magnetism will be the method to save the management cost of horticultural market by early shipment. As a results of this experiment, plants treated with magnets showed excellent growth especially in length growth. The experiment results of the respective plants are the following. 1. Rhapis flabelliformis : This have grown so very well in the container lined with magnets as time goes by. Showing the significant(p<0.05) differences, the length growth of Height and Length of leaves was especially distinguished. 2. Howea belmoreana : This has grown well in all containers. Showing the significant(p<0.05) differences, the length growth of Height and Length of leaves was especially distinguished. 3. Chamaedorea seifrizii : There have been the growth differences between Height and Length of leaves as time goes by. The growth of Height and Length of leaves in the container lined with magnets has been excellent. The number of leaves and number of branch generally had no big differences but the growth of Height and Length of leaves was excellent in the magnet container. The method of plant growth promotion with magnet should save the management cost for this reason. Therefore the succeeding studies about the plant growth under the influence of magnet intensity and kind must be performed. The studies with various plants are needed to activate the program for growing plants with magnet.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2003년도 High Temperature Superconductivity Vol.XIII
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• pp.17-17
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• 2003

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2009년도 Korea Superconductivity Society Meeting 2009
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• pp.17-17
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• 2009

• Journal of Magnetics
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• 제21권2호
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• pp.235-238
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• 2016

Microstructure and magnetization behaviors of $MnBi/Fe_3B/Nd2_Fe_{14}B$ nanocomposite alloy have been investigated. It was found that the coercivity increased firstly and then decreased, and saturation magnetization decreased with the additon of MnBi alloy. The addition of 40 wt.% MnBi powder enhanced the coercivity from 192.8 kA/m to 311.2 kA/m. The ${\delta}M$ and D(H)-H plots suggested the occurrence of a stronger exchange-coupling occurring between the hard and soft magnetic phase for this sample. The dependence of coercivity with temperature was discussed in 40 wt.% $Mn_{55}Bi_{45}$/ 60 wt.% $Nd_{4.5}Fe_{76.5}Nb_{0.5}B_{18.5}$ alloy powder, and a positive temperature coefficient was founded from 298 K to 350 K.

• Journal of Magnetics
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• 제13권4호
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• pp.140-143
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• 2008

The magnetic and structural properties of transition metal (Mn, Fe, Co) monolayers on Ta(001) surfaces are investigated theoretically by using the first principles full-potential linearized augmented plane wave method. Mn and Fe monolayers become ferromagnetic on Ta(001) surfaces while Co monolayers becomes non-magnetic. The paramagnetism of Co monolayers is explained by the Stoner theory of magnetism. The magnetic coupling of a transition metal overlayer with a substrate is ascribed to the orbital hybridization between the s and d orbitals of the transition metal.

• 한국항해학회지
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• 제14권1호
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• pp.1-7
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• 1990

A theoretical model for the over-all ship's magnetism was developed, on the assumption that the magnetism of a three-island type vessel can be regarded as that of the prolate spheroidal magnetic body. Modelled values were determined by the simulation on the base of the theoretical analysis of the magnetic field around the above-mentioned magnetic body. The real values were made of the data observed from four different three-islands type vessels alongside the piers. The agreement between the modelled and real values was found to be accurate.

• Journal of Korean Vacuum Science & Technology
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• 제3권2호
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• pp.134-138
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• 1999

We have setup a compact and useful in-situ SMOKE system in order to study surface magnetism of ultra-thin films. Since the longitudinal or polar magnetic fields can be applied to the sample by just rotating the sample manipulator, It is very simple to take hysteresis curve for in-plane or polar surface magnetism. The SMOKE system was tested by investigating the surface magnetism of ultra-thin Co film deposited on Pt(111) surface.