Octahedron-shaped three-shell Ln14-substituted polyoxotungstogermanates encapsulating a W4O15 cluster: luminescence and frequency dependent magnetic properties

2019 ◽  
Vol 55 (19) ◽  
pp. 2857-2860 ◽  
Author(s):  
Yong-Jiang Wang ◽  
Shi-Yu Wu ◽  
Yan-Qiong Sun ◽  
Xin-Xiong Li ◽  
Shou-Tian Zheng
Keyword(s):  
Magnetic Properties ◽  
Shell Structure ◽  
Frequency Dependent

The octahedron-shaped three-shell structure of the [(Ln14(H2O)W4(OH)O14)(WO4)4(GeW10O38)6]43− polyanion contains a W4 tetrahedron, a Ln14W4 tetrahedron and a Ge6W60 octahedron.

Microstructure and magnetic properties of SiO2/FeCoNiSi0.25 high-entropy alloy with a core/shell structure

2021 ◽  
Vol 290 ◽  
pp. 129399
Author(s):  
Shaofeng Yang ◽  
Jianan Wen ◽  
Fangyang Zhang ◽  
Jingyi Xie ◽  
Jiao Mo ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Shell Structure ◽  
High Entropy Alloy ◽  
Core Shell ◽  
High Entropy ◽  
Core Shell Structure ◽  
Microstructure And Magnetic Properties

Preparation and magnetic properties of SrFe12O19/SiO2 nanocomposites with core–shell structure

2007 ◽  
Vol 61 (11-12) ◽  
pp. 2187-2190 ◽  
Author(s):  
Wuyou Fu ◽  
Haibin Yang ◽  
Qingjiang Yu ◽  
Jing Xu ◽  
Xiaofen Pang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Shell Structure ◽  
Core Shell ◽  
Sio2 Nanocomposites ◽  
Core Shell Structure

scholarly journals Magnetic Susceptibility of Soils from Eastern Botswana: A Reconnaissance Survey and Potential Applications

2015 ◽  
Vol 7 (4) ◽  
pp. 45 ◽  
Author(s):  
Rubeni Tawanda Ranganai ◽  
Moikwathai Moidaki ◽  
James G. King
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Land Use Planning ◽  
Magnetic Measurements ◽  
Parent Material ◽  
Appreciable Amount ◽  
Frequency Dependent ◽  
Magnetic Susceptibilities ◽  
Basement Rocks ◽  
Rock And Soil

<p class="zhengwen">Soil magnetic properties measurements are relatively fast and inexpensive but have been proved to be sufficient for preliminary investigations in diverse socio-developmental issues. This paper presents results of a reconnaissance study of soil colour and magnetic susceptibility (c) in eastern Botswana, where ~80% of the population resides. The work is a first step to creating a database of rock and soil magnetic properties and to document spatial variations in magnetic properties in the country. These measurements are important as constraints for interpretation of available aeromagnetic data and can also be exploited for environmental soil research (pollution) and land-use planning (agriculture). The soils sampled include derivatives of varying types and provenance such as Archean gneissic granitoids, metamorphosed rocks (granulites), volcano-sedimentary assemblages, Karoo basalts, and alluvial sediments. A soil colour chart was used since soil colours and magnetic properties are diagnostic of its parent rock sources and weathering profiles. Soil magnetic susceptibilities were measured at both low frequency (0.46 MHz, clf) and high frequency (4.6 MHz, chf), thus allowing calculation of frequency-dependent susceptibility (cfd, cfd%) for detecting ultra-fine ferromagnetic minerals.</p>It was found that soils with Hues ranging from 7.5YR to 10YR have appreciable amount of magnetic materials and soils with Hues of 2.5YR are generally nonmagnetic. The results of soil magnetic susceptibility profiles show spatial variation closely related to the variation in basement rocks, which provides excellent evidence that the magnetic susceptibility variation reflects basement rocks or bedrock composition (soil parent material). In relation to the Botswana physiographic units, soils from the hardveld (Precambrian) show the highest susceptibilities, followed by those from the sandveld, with the lowest values being from the alluvial. The frequency dependent magnetic susceptibilities indicate the presence of ultra-fine super-paramagnetic minerals such as magnetite/maghemite. It is suggested that a systematic and continuous programme of rock and soil magnetic measurements would benefit various socio-economic and development priority sectors of Botswana. This also applies to many developing countries in Africa where soil physics and measurement of soil susceptibility in particular, is generally still at an embryonic stage.

scholarly journals High Photocatalytic Activity of Fe3O4-SiO2-TiO2Functional Particles with Core-Shell Structure

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Chenyang Xue ◽  
Qiang Zhang ◽  
Junyang Li ◽  
Xiujian Chou ◽  
Wendong Zhang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Photocatalytic Activity ◽  
Shell Structure ◽  
Sol Gel ◽  
High Photocatalytic Activity ◽  
Core Shell ◽  
Large Area ◽  
Uniform Size ◽  
Functional Nanoparticles ◽  
Core Shell Structure

This paper describes a novel method of synthesizing Fe3O4-SiO2-TiO2functional nanoparticles with the core-shell structure. The Fe3O4cores which were mainly superparamagnetic were synthesized through a novel carbon reduction method. The Fe3O4cores were then modified with SiO2and finally encapsulated with TiO2by the sol-gel method. The results of characterizations showed that the encapsulated 700 nm Fe3O4-SiO2-TiO2particles have a relatively uniform size distribution, an anatase TiO2shell, and suitable magnetic properties for allowing collection in a magnetic field. These magnetic properties, large area, relative high saturation intensity, and low retentive magnetism make the particles have high dispersibility in suspension and yet enable them to be recovered well using magnetic fields. The functionality of these particles was tested by measuring the photocatalytic activity of the decolouring of methyl orange (MO) and methylene blue (MB) under ultraviolet light and sunlight. The results showed that the introduction of the Fe3O4-SiO2-TiO2functional nanoparticles significantly increased the decoloration rate so that an MO solution at a concentration of 10 mg/L could be decoloured completely within 180 minutes. The particles were recovered after utilization, washing, and drying and the primary recovery ratio was 87.5%.

Microstructure and magnetic properties of Fe–6.5 wt.% Si/MnZn(Fe2O4)2 composites with core-shell structure prepared by spark plasma sintering

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744013 ◽  
Author(s):  
Liang Yan ◽  
Biao Yan
Keyword(s):  
Magnetic Properties ◽  
Shell Structure ◽  
Core Shell ◽  
Soft Magnetic ◽  
Magnetic Composites ◽  
Plasma Sintering ◽  
Soft Magnetic Composites ◽  
Spark Plasma ◽  
Core Shell Structure ◽  
Microstructure And Magnetic Properties

Fe–6.5 wt.% Si powder coated with 10 wt.% MnZn(Fe2O4)2 (MnZn ferrite) was successfully prepared by using dry-type stirring ball milling. The Fe–6.5 wt.% Si/MnZn(Fe2O4)2 soft magnetic composites were prepared by subsequent spark plasma sintering. This paper aims at analyzing the microstructure and magnetic properties of Fe–6.5 wt.% Si/MnZn(Fe2O4)2 soft magnetic composites (sintering temperature: 750[Formula: see text]C, sintering pressure: 50 MPa, holding time: 8 min, heating rate: 60 K/min). Based on X-ray diffraction and scanning electron microscopy, microstructure and powder morphology were examined and magnetic measurements on bulk samples were conducted by vibrating sample magnetometer and impedance analyzer. According to the experiments results, Fe–6.5 wt.% Si/MnZn(Fe2O4)2 composites displayed a core-shell structure, and ceramic phase was observed after sintering. The Fe–6.5 wt.% Si/MnZn(Fe2O4)2 composites achieved high resistivity ([Formula: see text] m[Formula: see text]/cm) while maintaining excellent magnetic properties ([Formula: see text] emu/g). Core losses especially at medium and high frequencies were significantly reduced.

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