La_2 VMnO_6 is measured to be insulating and ferrimagnetic experimentally. In this study, by substituting V with Nb, La2 NbMnO_6 is investigated using the density functional theory. The calculated results indicate tha...La_2 VMnO_6 is measured to be insulating and ferrimagnetic experimentally. In this study, by substituting V with Nb, La2 NbMnO_6 is investigated using the density functional theory. The calculated results indicate that La_2 NbMnO_6 is also ferrimagnetic and exhibits the half metallic properties due to the strong electron correlation of Mn. The valence states of Nb and Mn are assigned to be+4 and+2 in La_2 NbMnO_6, respectively, which are different from V^(3+)/Mn^(3+) in La_2 VMnO_6.展开更多
A theoretical model to simulate an end-pumped CW Nd 3+ :GdVO 4 laser at 1063 nm is presented. Its essence is to use the propagation equations to demonstrate the spatial evolutions of the pump and the laser powers in t...A theoretical model to simulate an end-pumped CW Nd 3+ :GdVO 4 laser at 1063 nm is presented. Its essence is to use the propagation equations to demonstrate the spatial evolutions of the pump and the laser powers in the cavity, hence it is applicable to both low and high gain lasers. The simulation results obtained by this model are in good agreement with the experimental observations reported in the literature for a Ti:sapphire-pumped Nd 3+ :GdVO 4 laser. Moreover, some parameters, such as the reflectivity of output coupler, the spot size of laser beam and the crystal length, are discussed with a view to optimizing the laser performance.展开更多
Radio-frequency microdischarge in acetylene is investigated by use of a fluid model and an aerosol dynamics model in a cylindrical discharge chamber.In this article,the results at a pressure of 100–500 Torr,a voltage...Radio-frequency microdischarge in acetylene is investigated by use of a fluid model and an aerosol dynamics model in a cylindrical discharge chamber.In this article,the results at a pressure of 100–500 Torr,a voltage of 80–150 V,and an electrode gap of 400–1000μm are carefully analyzed and discussed.It is shown that two electron heating modesαandγappear in the microdischarge,and the pressure-dependent transition fromαtoγwas accompanied by the abrupt decrease of electron density and electron temperature.The mode transition phenomenon is further confirmed by the variation of the electron temperature axial profiles,the profiles vary continuously from a center high at the pressure of 100 Torr to an edge high at the pressure of500 Torr.Furthermore,in theαmode(100 Torr)the plasma density increases linearly with the increase of electrode gap,but decreases sharply with the increase of electrode gap in theγmode(>100 Torr).The gas pressure and applied voltage effects on the nanoparticle density and degree of nonuniformity are also investigated.It has been shown that the gas pressure greatly influences the axial profiles of nanoparticle density and the values of the degree of nonuniformity,while the values of the plasma parameters(electron density and nanoparticle density)strongly depend on the applied voltage.展开更多
基金Supported by the Scientific Research Plan Projects of Heilongjiang Education Department under Grant No 135109311the National Natural Science Foundation of China under Grant Nos 11404180 and 11405092the Natural Science Foundation of Heilongjiang Province under Grant Nos A2015010 and B201420
文摘La_2 VMnO_6 is measured to be insulating and ferrimagnetic experimentally. In this study, by substituting V with Nb, La2 NbMnO_6 is investigated using the density functional theory. The calculated results indicate that La_2 NbMnO_6 is also ferrimagnetic and exhibits the half metallic properties due to the strong electron correlation of Mn. The valence states of Nb and Mn are assigned to be+4 and+2 in La_2 NbMnO_6, respectively, which are different from V^(3+)/Mn^(3+) in La_2 VMnO_6.
基金supported by the National Natural Science Foundation of China (Grant No 10104009)
文摘A theoretical model to simulate an end-pumped CW Nd 3+ :GdVO 4 laser at 1063 nm is presented. Its essence is to use the propagation equations to demonstrate the spatial evolutions of the pump and the laser powers in the cavity, hence it is applicable to both low and high gain lasers. The simulation results obtained by this model are in good agreement with the experimental observations reported in the literature for a Ti:sapphire-pumped Nd 3+ :GdVO 4 laser. Moreover, some parameters, such as the reflectivity of output coupler, the spot size of laser beam and the crystal length, are discussed with a view to optimizing the laser performance.
基金Project supported by the National Natural Science Foundation of China （Grant No 10074020）.Acknowledgement The authors would like to thank Professor Siyuan Zhang for providing Er^3＋：YAG crystal.
基金supported by National Natural Science Foundation of China(Nos.11805107 and 21703112)the Fundamental Research Funds in Heilongjiang Provincial Universities of China(No.135209312).
文摘Radio-frequency microdischarge in acetylene is investigated by use of a fluid model and an aerosol dynamics model in a cylindrical discharge chamber.In this article,the results at a pressure of 100–500 Torr,a voltage of 80–150 V,and an electrode gap of 400–1000μm are carefully analyzed and discussed.It is shown that two electron heating modesαandγappear in the microdischarge,and the pressure-dependent transition fromαtoγwas accompanied by the abrupt decrease of electron density and electron temperature.The mode transition phenomenon is further confirmed by the variation of the electron temperature axial profiles,the profiles vary continuously from a center high at the pressure of 100 Torr to an edge high at the pressure of500 Torr.Furthermore,in theαmode(100 Torr)the plasma density increases linearly with the increase of electrode gap,but decreases sharply with the increase of electrode gap in theγmode(>100 Torr).The gas pressure and applied voltage effects on the nanoparticle density and degree of nonuniformity are also investigated.It has been shown that the gas pressure greatly influences the axial profiles of nanoparticle density and the values of the degree of nonuniformity,while the values of the plasma parameters(electron density and nanoparticle density)strongly depend on the applied voltage.
