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Andrejs Petruhins Arni Sigurdur Ingason Martin Dahlqvist Aurelija Mockute Muhammad Junaid Jens Birch Jun Lu Lars Hultman Per O. Å. Persson Johanna Rosen 《固体物理学:研究快报》2013,7(11):971-974
Ab‐initio calculations have been used to investigate the phase stability and magnetic state of Crn+ 1GaCn MAX phase. Cr2GaC (n = 1) was predicted to be stable, with a ground state corresponding to an antiferromagnetic spin configuration. Thin‐film synthesis by magnetron sputtering from elemental targets, including liquid Ga, shows the formation of Cr2GaC, previously only attained from bulk synthesis methods. The films were deposited at 650 °C on MgO(111) substrates. X‐ray diffraction and high‐resolution transmission electron microscopy show epitaxial growth of (000?) MAX phase. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Mériguet G Cousin F Dubois E Boué F Cebers A Farago B Perzynski R 《The journal of physical chemistry. B》2006,110(9):4378-4386
In the present study, the structure of monophasic ionic magnetic fluids under a static magnetic field is explored. In these aqueous electrostatically stabilized ferrofluids, we vary both the isotropic interparticle interactions and the anisotropic dipolar magnetic interaction by tuning the ionic strength and the size of the nanoparticles. Small angle neutron scattering measurements carried out on nanoparticles dispersed in light water exhibit miscellaneous 2D nuclear patterns under a magnetic field with various q-dependent anisotropies. In this nondeuterated solvent where the magnetic scattering is negligible, this anisotropy originates from an anisotropy of the structure of the dispersions. Both the low q region and the peak of the structure factor can be anisotropic. On the scale of the interparticle distance, the structure is better defined in the direction perpendicular to the field. In the thermodynamic limit (q-->0), the model previously described in ref 10 matches the data without any fitting parameters: the interparticle interaction is more repulsive in the direction parallel to the magnetic field. At low q, the amplitude of the anisotropy of the pattern is governed by the ratio of two interaction parameters: the reduced parameter of the anisotropic magnetic dipolar interaction, gamma/Phi, over the isotropic interaction parameter, , in zero field, which is proportional to the second virial coefficient. 相似文献
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O. Dumbrajs H. Kalis A. Reinfelds 《International Journal of Infrared and Millimeter Waves》2005,26(6):787-805
Limits on the power generated by coaxial gyrotrons are investigated. It is shown that among all the operating modes suggested recently for coaxial super power gyrotrons only modes with azimuthal index m lower than about 44 pass the spatial stochasticity test. Modes with higher azimuthal indices cannot be used as operating modes because gyrotron oscillations become chaotic in the azimuthal direction and efficiency is very low. It is argued that there exists a natural upper limit on power generated by gyrotrons which is about 4 MW. 相似文献
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Diffusion coefficients were obtained for two compositions of the system H2O-sucrose-KCl at 25°C. These plus published diffusion coefficients of the same system at two other compositions led to the construction of three-dimensional surface diagrams. Using these diagrams, the diffusion coefficients of the ternary system were compared with those of binary systems of components. The main diffusion coefficient of KCl was estimated from the conductivity data of KCl in aqueous solution of sucrose, and the agreement of these with experimental values was found to be satisfactory. The possible cause for the appreciable size of the cross-term diffusion coefficients is discussed. 相似文献
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