Analysis Of The Permeability Spectra Of Spinel Ferrite Composites Using Mixing Rules

Magnetic permeability spectra of composite materials containing spinel ferrites (Ni-Zn or Mn-Zn types) have been studied using a permeability dispersion formula by the numerical analysis. The variation of d.c. permeability and the frequency dispersion parameters due to domain wall and gyromagnetic spin resonances with particle content were evaluated using two mixing rules, Coherent Model Approximation (CMA) and Maxwell-Garnet Approximation (MGA) assuming the isotropic particle shape. The variation of d.c. permeability with particle content for spinel ferrite composite can be predicted by the CMA and MGA using the permeability value of embedded ferrite. The dc susceptibility and resonance frequency of domain wall and spin components estimated by the numerical analysis can also be qualitatively described by the CMA and MGA. The type of frequency dispersion, relaxation or resonance, for domain wall and spin components can be analyzed by the estimated damping factors. © 2013 IEEE

Electromagnetic Properties Of Metal Granular Composite Materials For EMC Applications

Electromagnetic properties of copper and Fe55Ni45alloy (Permalloy) composite materials have been studied by measuring the relative complex permeability (µr = µr’– jµr”), and permittivity (Σr = Σr’– jΣr”) spectra over the microwave range, as well as the a.c. electrical conductivity σac spectra. The variation of σac and Σr with particle content shows the insulator-metal transition due to the percolation effect. The effective cluster model can be applied to the percolation effect in permittivity. The permeability spectra in Permalloy composites, which contain the percolated particles, can be affected by the eddy current effect. The permeability relaxation frequency of Permalloy composites shifts to the higher frequencies by the oxidation of embedded particle surfaces. © 2012 IEEE

High Frequency Permeability Of Fe-Al-Si Granular Composite Materials

High-frequency electromagnetic properties of Fe-Al-Si alloy (Sendust) granular composite materials have been studied by measuring their relative complex permeability (μr = μr’ – jμr”) and permittivity (εr = εr’ – j εr”) spectra. The bulk Fe-Al-Si alloy shows metallic electrical conduction, and permeability decreases rapidly with frequency. On the other hand, Sendust powder shows relatively high electrical resistivity. Sendust composite material demonstrates insulating electrical properties up to at least 80 vol.% particle content. Thus the relatively high permeability in the microwave frequency range can be obtained. Frequency dispersion characteristics of permeability for the composite were analyzed by the superposition of domain wall and gyromagnetic spin resonance formula. The particle content variation of permeability can be qualitatively described by a coherent model mixing rule. © 2011 IEEE

Development of an energy and environmental education program dealing with social issues

In the 3rd grader of junior high school, we propose a new subject "resources and energy" dealing with social issues. Through this subject, we aim to foster the ability to think from a multifaceted and integrated viewpoint. We conducted a questionnaire survey whether students understand about scientific or social terms related to energy in the next year. The degree of understanding of the students who learned the program was high. And there were many students who thought that social issues could be solved by science and technology in future in comparison with groups that did not study this program

Attenuation in Extended Structures Coated with Thin Magneto-Dielectric Absorber Layer

Thin absorbing layers containing magnetic alloy or ferrite inclusions can be effectively used for attenuating common-mode currents on extended structures, such as power cords, cables, or edge-coupled microstrip lines. An analytical model to evaluate attenuation on the coaxial line with the central conductor coated with a magneto-dielectric layer is proposed and validated by the experiments and numerical modeling. The analytical model is validated using available magneto-dielectric samples of different thicknesses. This model can serve for comparing and predicting the absorptive properties of different samples of magneto-dielectric materials, whose compositions may be unknown, but dielectric and magnetic properties can be determined by independent measurements over the specified frequency ranges. From modeling the absorption in a coaxial line with a wrapped central conductor, it could be concluded whether it is reasonable to use this particular material in such applications as a shield on an Ethernet or other cable, for reducing potential common-mode currents and unwanted radiation in the frequency range of interest

Promotion of Secondary School Science Education Driven by Inquiry-Based Activity

This article reports fundamental researches organized for developing a novel teaching/learning system in secondary school science. A curriculum constructed by an effective integration of content-based and context-based curriculum arrangements is proposed for generating teaching/learning opportunities through various inquiry-based activities on the basis of previously acquired science knowledge and concepts. The science subjects, including physics, chemistry, biology and earth science, have different logics and methodologies of science, but those are completed by mutual interdependences. Therefore, various storylines that cover different leraning contents in science subjects can be developed. The inquiry-based activities along different storylines provide students with opportunities to correlate previous learnings in different science subjects and to experience various cognitive and scientific skills. Based on such findings of our basic researches, the merits of the science education system proposed in this study is discussed briefly.本研究は，科学研究費補助金基盤研究(A)(一般)(25242015)による

異教科で協働できる教員を育成するための実践的研究（1） : 教科教育学専攻の共通科目の始動を通じて

本研究は，平成28 年度より始まった「教科教育学専攻」における新しい共通科目（「教科教育学研究方法論」，「教科教育学融合プロジェクト」，「教科教育学の実践的展開」，「教科教育学の実践的検証」）が始動する際に得られた知見を分析・考察し報告するもので，その全容は平成29 年３月に公開予定のホームページで公表される。本報告書は，その研究の要旨を，(1)　経緯について，(2)　各教科について，(3)　実践からの考察，(4)　理論からの考察，(5)　学生の振り返りからの考察の五点から述べる

Active Learning Models in Science Classes

研究の第１年次に当たる本年は，理科におけるアクティブラーニング型授業の構造化に向けて，内化と外化の往還を取り入れた授業デザインとその実践に取り組み，具体的実践の蓄積を行った。小学校，中学校，高等学校それぞれで実践を行ったところ，１）学習内容の定着が図られる，２）発展的な内容や未習内容を生徒が主体的に理解することが可能である，３）協働的な学びの場面を加えることで理解の深化が図られる，４）どのような課題に取り組ませるのかといった課題の設定がカギである，５）アクティブラーニングであるか否かを判断するための要素を明らかにする必要がある，などの一定の成果と課題が明らかになった。The purpose of this study is to create active learning models in science classes. As the first-year research, the authors designed the classes which would include a round trip between externalization and internalization, and put them into practice. The designed models were adopted in elementary, junior high and senior high school classes. What have become clear are as the following; 1) Students’ acquisition of the learning contents can be promoted, 2) Students can understand advanced contents proactively, 3) Students’ learning can be deepened by adding collaborative activities, 4) The success or failure to active learning may depend on the quality of the tasks which students work on, 5) It is necessary to clarify the factors to determine active learning