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Phase structure and magnetocaloric effect of (Tb_(1–x)Dy_x)Co_2 alloys
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作者 庄应烘 陈湘 +2 位作者 周开文 李克峰 马春华 《Journal of Rare Earths》 SCIE EI CAS CSCD 2008年第5期749-752,共4页
Phase structure and magnetocaloric effect of (Tb1-xDyx)Co2 alloys with x=0, 0.2, 0.4, 0.6, 0.8, and 1.0 were investigated using X-ray diffraction analysis, differential thermal analysis, and magnetization measuremen... Phase structure and magnetocaloric effect of (Tb1-xDyx)Co2 alloys with x=0, 0.2, 0.4, 0.6, 0.8, and 1.0 were investigated using X-ray diffraction analysis, differential thermal analysis, and magnetization measurement. The samples were single phase with cubic MgCu2- type structure; with the increase of Dy content, Tc decreased from 240 K (TbCo2) to 130 K (DyCo2), and the maximum magnetic entropy change | △SM,max| increased from 3.133 to 8.176 J/kg-K under low magnetic field of 0-2 T. The Arrott plot and the change of |△SM,max| showed that magnetic phase transition from second order to first order occured with the increase of Dy content between x=-0.6 and 0.8. 展开更多
关键词 magnetic refrigeration materials magnetocaloric effect magnetic phase transition (Tb1-xDyx)Co2 alloys rare earths
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Mechanical Properties and Electronic Structure of N and Ta Doped TiC: A First-Principles Study 被引量:1
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作者 马世卿 刘颖 +1 位作者 叶金文 王斌 《Communications in Theoretical Physics》 SCIE CAS CSCD 2014年第12期895-902,共8页
The first principles calculations based on density functional theory(DFT) are employed to investigate the mechanical properties and electronic structure of N and Ta doped Ti C. The result shows that the co-doping of n... The first principles calculations based on density functional theory(DFT) are employed to investigate the mechanical properties and electronic structure of N and Ta doped Ti C. The result shows that the co-doping of nitrogen and tantalum dilates the lattice constant and improves the stability of Ti C. Nitrogen and tantalum can significantly enhance the elastic constants and elastic moduli of Ti C. The results of B/G and C12-C44 indicate tantalum can markedly increase the ductility of Ti C. The electronic structure is calculated to describe the bonding characteristic, which revealed the strong hybridization between C-p and Ta-d and between N-p and Ti-d. The hardnessis is estimated by a semiempirical model that is based on the Mulliken overlap population and bond length. While the weakest bond takes determinative role of the hardness of materials, the addition of Ta sharply reduces the hardness of Ti C. 展开更多
关键词 density functional theory ELASTIC properties electronic structure HARDNESS Ti-Ta-C-N QUATERNARY alloy
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Distinguishing high-harmonic generation from surface and bulk states in topological insulator Bi_(2)Se_(3) 被引量:1
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作者 江阳 白亚 +3 位作者 叶泽奕 李娜 刘灿东 刘鹏 《Chinese Optics Letters》 SCIE EI CAS CSCD 2023年第4期137-142,共6页
We demonstrated a scheme to differentiate the high-harmonic generation[HHG)originating from the surface states and bulk states of the topological insulator Bi_(2)Se_(3).By adopting two-color mid-infrared laser fields ... We demonstrated a scheme to differentiate the high-harmonic generation[HHG)originating from the surface states and bulk states of the topological insulator Bi_(2)Se_(3).By adopting two-color mid-infrared laser fields on Bi_(2)Se_(3),we found that the nonlinear response sensitively depends on the relative phase of the driving fields.The even harmonics arise from the surface states with a clear signature,whose modulation period equals the cycle of the second-harmonic generation[SHG]field.We reveal that the weak SHG perturbs the nontrivial dipole phase of the electron-hole pair in surface states,and thus leads to the modulation of HHG.It provides a means to manipulate the ultrafast dynamics in surface states through adopting a weak perturbing laser field. 展开更多
关键词 high-harmonic generation topological insulators two-color laser fields
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