We present a method to quantify the spin Hall angle (SHA) with spin pumping and microwave photoresistance measurements. With this method, we separate the inverse spin Hall effect (ISHE) from other unwanted effects for permalloy/Pt bilayers using out-of-plane microwave excitation.Through microwave photoresistance measurements, the in-and out-of-plane precessing angles of the magnetization are determined and enabled for the exact determination of the injected pure spin current. This method is demonstrated with an almost perfect Lorentz line-shape for the obtained ISHE signal and the frequency independent SHA value as predicted by theory. By varying the Pt thickness, the SHA and spin-diffusion length of Pt is quantified as 0.012 0.001 ± and 8.3 0.9 ± nm, respectively.
In this paper, we designed a novel core-shell composite for microwave absorption application in which the α-Fe2O3 and the porous CoFe2O4 nanospheres served as the core and shell, respectively. Interestingly, during the solvothermal process, the solvent ratio (V) of PEG-200 to distilled water played a key role in the morphology of α-Fe2O3 for which irregular flake, coin-like, and thinner coin-like forms of α-Fe2O3 can be produced with the ratios of 1:7, 1:3, and 1:1, respectively. The porous 70 nm diameter CoFe2O4 nanospheres were generated as the shell of α-Fe2O3. It should be noted that the CoFe2O4 coating layer did not damage the original shape of α-Fe2O3. As compared with the uncoated α-Fe2O3, the Fe2O3@CoFe2O4 composites exhibited improved microwave absorption performance over the tested frequency range (2-18 GHz). In particular, the optimal reflection loss value of the flake-like composite can reach -60 dB at 16.5 GHz with a thin coating thickness of 2 mm. Furthermore, the frequency bandwidth corresponding to the RLmin value below -10 dB was up to 5 GHz (13-18 GHz). The enhanced microwave absorption properties of these composites may originate from the strong electron polarization effect (i.e., the electron polarization between Fe and Co) and the electromagnetic wave scattering on this special porous core-shell structure. In addition, the synergy effect between α-Fe2O3 and CoFe2O4 also favored balancing the electromagnetic parameters. Our results provided a promising approach for preparing an absorbent with good absorption intensity and a broad frequency that was lightweight.
In this study, two-dimensional MoS2 nanosheets synthesized by a hydrothermal method were firstly investigated for microwave absorbing performance.
This paper reviews the study of the morphology and physical properties of fat crystal networks. Various microscopical and rheological methods can be used to quantify the microstructure of fats, with the ultimate aim of relating structure to mechanical response. Even though a variety of physical models have been proposed to explain the relationship between the mechanical properties of fats and their microstructure, the fractal scaling model most closely describes the experimentally observed behavior. Mass fractal dimensions determined by microscopy and rheology can be used successfully to quantify the microstructure of fats since fractal dimension values are sensitive to the combined effects of crystal size, morphology, and the spatial distribution of mass within the fat crystal network. Methods used to determine the fractal dimension of a fat crystal network such as box counting, particle counting, Fourier transform, light scattering, and oil migration are explained in detail here. The relationship between fractal dimensions determined by microscopy and rheology are discussed in light of the fact that different measures of the fractal dimension describe different microstructural features in a fat crystal network.In food products of high fat content, such as butter, margarine, and shortening, fat exists in a semisolid state, structured by an underlying fat crystal network (1-5). The physical properties of fat and food products containing fat are related to the structure of this fat crystal network (6-10). Like many other materials, fat crystal networks demonstrate distinct hierarchies of structural organization as shown in Figure 1 (11). Most of the studies on the structure and properties of fat crystal networks have concentrated mainly on lipid composition, polymorphism, and SFC (solid fat content). In general, few attempts have been made to establish relationships between the size, morphology, and mass distribution of fat crystals and the rheological properties of fats.Most of the studies on the microstructure of fat crystal networks qualitatively describe the general trends of how processing conditions change the size and morphology of fat crystal clusters and the rheological properties of fat crystal networks. Many microscopy techniques, for example, PLM (polarized light microscopy) (9,11-16), SEM (scanning electron microscopy) (12,(17)(18)(19), CSLM (confocal scanning light microscopy) (20), FFEM (freeze-fracture electron microscopy) (21,22), and cryo-SEM (23), have been used to visualize the microstructure of fat crystal networks. Although in these studies the relationship between the physical properties and the microstructure of fats was not studied quantitatively, these studies allow us to gain a deeper understanding of the structure of fat crystal networks and provide valuable data for further analysis.In addition to microscopy, large-and small-deformation rheology has been used to probe the microstructure of fat crystal networks. Moreover, oil migration and light-scattering techniques have served the sam...
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