The Er Al2@Al2O3 nanocapsules with Er Al2core and Al2O3 shell were synthesized by modified arc-charge technique.The typical core-shell structure of the nanocapsules was confirmed by high resolution transmission electr...The Er Al2@Al2O3 nanocapsules with Er Al2core and Al2O3 shell were synthesized by modified arc-charge technique.The typical core-shell structure of the nanocapsules was confirmed by high resolution transmission electron microscopy and X-ray photoelectron spectroscopy.Transmission electron microscopy analysis shows the irregular sphere of the nanocapules with an average diameter of 26 nm.Magnetic investigation revealed the Curie temperature of Er Al2@Al2O3 nanocapsules at 20 K and the typical superparamagnetic behavior between blocking temperature and Curie temperature.Based on the blocking temperature and average diameter,the magnetocrystalline anisotropy constant of Er Al2@Al2O3nanocapsules was estimated to illustrate the magnetic contribution to the-SM.The large-SMof 14.25 J/（kg K）was obtained under 50 k Oe at 5 K.A vital parameter β was introduced in the present work to scale the optimized magnetic characteristics and the optimized mechanism was discussed in detail according to classical superparamagnetic theory.The results demonstrate that the optimal-SMwill be obtained when the magnetic parameter β is close to the theoretical coefficient.展开更多
Topological crystalline insulator(TCI)as a new type of topological materials has attracted extensive research interests for its tunable topological properties.Due its symmetry topological protection essence,the struct...Topological crystalline insulator(TCI)as a new type of topological materials has attracted extensive research interests for its tunable topological properties.Due its symmetry topological protection essence,the structure investigation provides a solid basement for tuning its topological transport properties.On SrTiO3(111)substrate,the SnTe film was found to be epitaxial growth only along[001]while not[111]direction.The detailed structural study was performed and a structural model was proposed to elucidate epitaxial growth of the SnTe(001)film.The transport properties of SnTe(001)film were further investigated and a typical weak anti-localization effect was observed.By Pb-doping into SnTe,the bulk carriers were inhibited and its topological surface states were strengthened to induce the enhanced surface transport contribution.With tunable multiple transport channels from the even Dirac cones,the TCI SnTe film systems will have the potential application in future spintronics devices.展开更多
The large-scale popularization of electric vehicles(EVs)brings the potential for grid frequency regulation.Considering the characteristics of fast response and adjustment of EVs,two control strategies of automatic gen...The large-scale popularization of electric vehicles(EVs)brings the potential for grid frequency regulation.Considering the characteristics of fast response and adjustment of EVs,two control strategies of automatic generation control(AGC)with EVs are proposed responding to two high frequency regulating signals extracted from area control error(ACE)and area regulation requirement(ARR)by a digital filter,respectively.In order to dispatch regulation task to EVs,the capacity of regulation is calculated based on maximum V2G power and the present V2G power of EVs.Finally,simulations based on a two-area interconnected power system show that the proposed approaches can significantly suppress frequency deviation and reduce the active power output of traditional generation units.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.51271178,51571195,51331006,51590883)
文摘The Er Al2@Al2O3 nanocapsules with Er Al2core and Al2O3 shell were synthesized by modified arc-charge technique.The typical core-shell structure of the nanocapsules was confirmed by high resolution transmission electron microscopy and X-ray photoelectron spectroscopy.Transmission electron microscopy analysis shows the irregular sphere of the nanocapules with an average diameter of 26 nm.Magnetic investigation revealed the Curie temperature of Er Al2@Al2O3 nanocapsules at 20 K and the typical superparamagnetic behavior between blocking temperature and Curie temperature.Based on the blocking temperature and average diameter,the magnetocrystalline anisotropy constant of Er Al2@Al2O3nanocapsules was estimated to illustrate the magnetic contribution to the-SM.The large-SMof 14.25 J/（kg K）was obtained under 50 k Oe at 5 K.A vital parameter β was introduced in the present work to scale the optimized magnetic characteristics and the optimized mechanism was discussed in detail according to classical superparamagnetic theory.The results demonstrate that the optimal-SMwill be obtained when the magnetic parameter β is close to the theoretical coefficient.
基金This work was supported financially by the National Natural Science Foundation of China(Nos.51571195 and 51590883)the National Key R&D Program of China(No.2017YFA0206301).
文摘Topological crystalline insulator(TCI)as a new type of topological materials has attracted extensive research interests for its tunable topological properties.Due its symmetry topological protection essence,the structure investigation provides a solid basement for tuning its topological transport properties.On SrTiO3(111)substrate,the SnTe film was found to be epitaxial growth only along[001]while not[111]direction.The detailed structural study was performed and a structural model was proposed to elucidate epitaxial growth of the SnTe(001)film.The transport properties of SnTe(001)film were further investigated and a typical weak anti-localization effect was observed.By Pb-doping into SnTe,the bulk carriers were inhibited and its topological surface states were strengthened to induce the enhanced surface transport contribution.With tunable multiple transport channels from the even Dirac cones,the TCI SnTe film systems will have the potential application in future spintronics devices.
基金This work was supported by Sino-US international Science and Technology Cooperation Project(Grant No.2016YFE0105300).
文摘The large-scale popularization of electric vehicles(EVs)brings the potential for grid frequency regulation.Considering the characteristics of fast response and adjustment of EVs,two control strategies of automatic generation control(AGC)with EVs are proposed responding to two high frequency regulating signals extracted from area control error(ACE)and area regulation requirement(ARR)by a digital filter,respectively.In order to dispatch regulation task to EVs,the capacity of regulation is calculated based on maximum V2G power and the present V2G power of EVs.Finally,simulations based on a two-area interconnected power system show that the proposed approaches can significantly suppress frequency deviation and reduce the active power output of traditional generation units.
