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  • Vietnam National University Journal of Science  (2)
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  • Vietnam National University Journal of Science  (2)
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  • 1
    Online Resource
    Online Resource
    Vietnam National University Journal of Science ; 2022
    In:  VNU Journal of Science: Mathematics - Physics Vol. 38, No. 1 ( 2022-03-24)
    In: VNU Journal of Science: Mathematics - Physics, Vietnam National University Journal of Science, Vol. 38, No. 1 ( 2022-03-24)
    Abstract: Bi1-xEuxFeO3 (BEFO) (x = 0.00 ÷ 0.10) materials were prepared by sol-gel method. The crystal structural, Raman scattering, magnetic and optical properties of BEFO were investigated by X-ray diffraction (XRD), Raman scattering spectroscopy, magnetic hysteresis (M-H) loops and fluorescence spectroscopy (FL), respectively. Obtained results of the characterization showed that Eu-doping affected structural, optical and magnetic properties of BFO materials. All samples were crystallized in the rhombohedral structure with R3C space group with crystal lattice parameters of a = 5.585 Å, c = 13.832 Å and the average crystal size of LXRD = 581 Å for BFO materials whereas the a, c and LXRD of Eu-doped samples decrease with the increasing of Eu3+ concentration. The analysis result of Raman scattering spectroscopy showed that the position of the characteristic peak for Bi-O covalent bonds shifts toward higher frequency when Eu3+ concentration increases, confirming the dopping substitution of Eu3+ ions into Bi-sites. Fluorescence spectra showed the enhancement of characteristic emission peaks with the increase of Eu concentration. All samples exhibited weak ferromagnetic behaviour with saturation magnetization of Ms = 0.006 emu/g and remnant magnetization of Mr = 0.004 emu/g for BFO materials. The value of Ms and Mr of Eu-doped BFO increases compared to those of undoped-BFO. The origin of ferromagnetism and fluorescence improvement has been discussed.
    Type of Medium: Online Resource
    ISSN: 2588-1124 , 2615-9341
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2022
    Location Call Number Limitation Availability
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  • 2
    Online Resource
    Online Resource
    Vietnam National University Journal of Science ; 2022
    In:  VNU Journal of Science: Education Research Vol. 38, No. 2 ( 2022-06-10)
    In: VNU Journal of Science: Education Research, Vietnam National University Journal of Science, Vol. 38, No. 2 ( 2022-06-10)
    Abstract: The quality of educators is a crucial foundation, which partly plays a decisive role in determining the quality and effectiveness of pedagogical activities and improving the eduational quality to meet the requirement of the General Education Program 2018. The research assesses the quality of teachers based on survey data of a sample collection of 651 teachers from three provinces including Hanoi, Nghe An, and Can Tho; focuses on analyzing the quality of educators according to teacher quality criteria to meet the General Education Program 2018. The result shows that most teachers (62.4%) self-assessed the quality of teachers at the level one “fully folowing requirement”, level two (19.7%) “actively implementing requirement”, level three (6.8%) “being an example for others”, level four (8%) “sharing experiences and creating new style to behave” and level five (3.2%) “training others”. The study also showed a statistically significant correlation between teachers' quality and their demographic characteristics such as age, gender, years of experience. However, the technical expertise and educational levels may insignificantly correlate with the teachers’ quality. This means that the teachers’ quality should be improved to successfully implement the Genereal Education Program 2018.
    Type of Medium: Online Resource
    ISSN: 2588-1159 , 2615-9325
    Language: Unknown
    Publisher: Vietnam National University Journal of Science
    Publication Date: 2022
    Location Call Number Limitation Availability
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