The temperature dependence of the anisotropy parameter of upper critical field γHe2 （T） = Hc2^‖ （T） /Hc2^⊥ （T） and London penetration depth γλ （T） = λ‖（T）/λ⊥ （T） are calculated using two-band Ginz...The temperature dependence of the anisotropy parameter of upper critical field γHe2 （T） = Hc2^‖ （T） /Hc2^⊥ （T） and London penetration depth γλ （T） = λ‖（T）/λ⊥ （T） are calculated using two-band Ginzburg-Landau theory for layered superconductors. It is shown that, with decreasing temperature the anisotropy parameter γHc2 （T） is increased, while the London penetration depth anisotropy γλ（T） reveals an opposite behavior. Results of our calculations are in agreement with experimental data for single crystal MgB2 and with other calculations..Results of an analysis of magnetic field Hc1 in a single vortex between superconducting layers are also presented.展开更多
Temperature dependence of tbe pair-breaking critical current density of MgB2, jd（T）, is studied using a two-band Ginzburg-Landau theory. The results are shown to be in good agreement with experimental data for the s...Temperature dependence of tbe pair-breaking critical current density of MgB2, jd（T）, is studied using a two-band Ginzburg-Landau theory. The results are shown to be in good agreement with experimental data for the superconducting magnesium diboride MgB2.展开更多
Temperature dependence of the magnetization M （T） of two-band superconductors is studied in the vicinity of upper critical field He2 by using a two-band Ginzburg-Landau （GL） theory. It is shown that magnetization ...Temperature dependence of the magnetization M （T） of two-band superconductors is studied in the vicinity of upper critical field He2 by using a two-band Ginzburg-Landau （GL） theory. It is shown that magnetization M（T） has a nonlinear character due to positive curvature of upper critical field Hc2（T） and temperature dependence of effective Ginzburg-Landau parameter Neff（T）. The results are shown to be in qualitative agreement with experimental data for the superconducting magnesium diboride, MgB2.展开更多
Theory of thermal fluctuations in two-band superconductors under an essentially homogeneous magnetic field is developed within the framework of the two-band Ginzburg-Landau theory. The fluctuating specific heat is cal...Theory of thermal fluctuations in two-band superconductors under an essentially homogeneous magnetic field is developed within the framework of the two-band Ginzburg-Landau theory. The fluctuating specific heat is calculated by using the optimized self-consistent perturbation approach and the results are applied to analyze the thermodynamic data of the iron-based superconductors Ba（1-x）KxFe2As2 with x -0.4, which have been suggested to have a two-band structure by recent experiments. We estimate the fluctuation strength in this material and find that the specific heat is described well with the Ginzburg number Gi = 4 · 10^-4. The influence of interband coupling strength is investigated and the result of the two-band Gaussian approximation approach is compared.展开更多
Many sampling formulas are available for processes in baseband (-a,a) at the Nyquist rate a/π. However signals of telecommunications have power spectra which occupate two bands or more. We know that PNS (periodic non...Many sampling formulas are available for processes in baseband (-a,a) at the Nyquist rate a/π. However signals of telecommunications have power spectra which occupate two bands or more. We know that PNS (periodic non-uniform sampling) allow an errorless reconstruction at rate smaller than the Nyquist one. For instance PNS2 can be used in the two-bands case (-a,-b)∪(b,a) at the Landau rate (a-b)/π We prove a set of formulas which are available in cases more general than the PNS2. They take into account two sampling sequences which can be periodic or not and with same mean rate or not.展开更多
We study the dynamics of an electron spin state transfer along a half-filled two-band model(TBM).It is shown that this solvable and realistic medium has an energy gap between the ground and first-excited states in the...We study the dynamics of an electron spin state transfer along a half-filled two-band model(TBM).It is shown that this solvable and realistic medium has an energy gap between the ground and first-excited states in the half-filled case.By connecting two qubits to two sites of the TBM,the system can accomplish a high-fidelity and long-distance quantum state transfer(QST).Moreover,numerical simulations have been performed for a finite system.The results show that the numerical and analytical results of the effective coupling strength agree well with each other.Furthermore,the investigation shows that the reduced density matrix also has high fidelity beyond the range of perturbation.展开更多
The salt-inclusion materials have drawn significant attention for their manifold structural chemistry and novel physical/chemical properties.Herein,two new salt-inclusion chalcohalides,[Cs_(6)Cl][Ga_(5)GeQ_(12)](Q=S,S...The salt-inclusion materials have drawn significant attention for their manifold structural chemistry and novel physical/chemical properties.Herein,two new salt-inclusion chalcohalides,[Cs_(6)Cl][Ga_(5)GeQ_(12)](Q=S,Se),have been discovered via hightemperature flux methods.The two isostructural compounds are constructed by porous[Ga_(5)GeQ_(12)]^(5−)layers with[ClCs_(6)]^(5+)octahedra filled in the holes.The[Ga_(5)GeQ_(12)]^(5−)layer is composed of the honeycomb-like(Ga/Ge)_(18)Q_(42)rings containing(Ga/Ge)_(3)Q_(9)trimer as basic unit.The band gaps of the two compounds are 3.90 and 2.89 eV,respectively.[Cs_(6)Cl][Ga_(5)GeS_(12)]exhibits interesting two-band emission properties which are related to the intermediate-band electronic structure revealed by density functional theory(DFT)calculations.Owing to the porous layered structure,[Cs_(6)Cl][Ga_(5)GeS_(12)]exhibits topological ion exchange ability towards Cd^(2+)ions with the maximum sorption capacity of 250 mg/g and high distribution coefficient(Kd)near 106 mL/g.This work further enriches the structural diversity of salt-inclusion materials and extends their potential application range to ion exchange adsorption.展开更多
To compare the ability of three different reconstruction procedures in restoring the posterior displacement of tibia and the posterior stability of the knee joint from 0° to 120°flexion. Methods ： Three po...To compare the ability of three different reconstruction procedures in restoring the posterior displacement of tibia and the posterior stability of the knee joint from 0° to 120°flexion. Methods ： Three posterior cruciate ligaments （PCL） reconstruction procedures were performed, namely two-band two-tunnel reconstruction, one-band anterior tunnel reconstruction and one-band posterior tunnel reconstruction. The posterior displacement of the tibia in relation to the femur was measured when a 200N posterior force was applied. Results： Within the flexion range of 0° to 30°, the displacement in the one-band posterior tunnel reconstruction showed little difference from that of an intact knee （P〉0.05）. But when the flexion exceeded 30°, especially when it exceeded 60°, the displacement in oneband posterior tunnel reconstruction was much greater than that of an intact knee （P〈0.01）. In two-band two-tunnel reconstruction and one-band anterior tunnel reconstruction, the displacement was approximately the same as that of an intact knee ranging from 0° to 120° （P〉0.05）, while a slight over-restriction might be found at some angles. Conclusions： Two-band reconstruction could effectively restrict the posterior displacement of the tibia and restore anterior, posterior stability of the knee joint within its full range of flexion. One-band anterior tunnel reconstruction also could maintain the posterior stability of the knee, while the result of one-band posterior tunnel reconstruction is the most unsatisfactory.展开更多
In the present paper, we investigate the existence of ferromagnetism in a two-band Hubbard model, by applying a recently-introduced method by us to study ferromagnetism in metallic dusters. We prove rigorously that th...In the present paper, we investigate the existence of ferromagnetism in a two-band Hubbard model, by applying a recently-introduced method by us to study ferromagnetism in metallic dusters. We prove rigorously that the ground state of this model is ferromagnetic if the intra-orbital Coulomb repulsion between electrons is infinitely strong and only one hole exists in the system. Our theorem improves a previous result. Furthermore, our method can also be applied to dead with the case of multiple holes.展开更多
文摘The temperature dependence of the anisotropy parameter of upper critical field γHe2 （T） = Hc2^‖ （T） /Hc2^⊥ （T） and London penetration depth γλ （T） = λ‖（T）/λ⊥ （T） are calculated using two-band Ginzburg-Landau theory for layered superconductors. It is shown that, with decreasing temperature the anisotropy parameter γHc2 （T） is increased, while the London penetration depth anisotropy γλ（T） reveals an opposite behavior. Results of our calculations are in agreement with experimental data for single crystal MgB2 and with other calculations..Results of an analysis of magnetic field Hc1 in a single vortex between superconducting layers are also presented.
基金NATO reintegration grant，TUBITAK research Foundation
文摘Temperature dependence of tbe pair-breaking critical current density of MgB2, jd（T）, is studied using a two-band Ginzburg-Landau theory. The results are shown to be in good agreement with experimental data for the superconducting magnesium diboride MgB2.
文摘Temperature dependence of the magnetization M （T） of two-band superconductors is studied in the vicinity of upper critical field He2 by using a two-band Ginzburg-Landau （GL） theory. It is shown that magnetization M（T） has a nonlinear character due to positive curvature of upper critical field Hc2（T） and temperature dependence of effective Ginzburg-Landau parameter Neff（T）. The results are shown to be in qualitative agreement with experimental data for the superconducting magnesium diboride, MgB2.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674007)
文摘Theory of thermal fluctuations in two-band superconductors under an essentially homogeneous magnetic field is developed within the framework of the two-band Ginzburg-Landau theory. The fluctuating specific heat is calculated by using the optimized self-consistent perturbation approach and the results are applied to analyze the thermodynamic data of the iron-based superconductors Ba（1-x）KxFe2As2 with x -0.4, which have been suggested to have a two-band structure by recent experiments. We estimate the fluctuation strength in this material and find that the specific heat is described well with the Ginzburg number Gi = 4 · 10^-4. The influence of interband coupling strength is investigated and the result of the two-band Gaussian approximation approach is compared.
文摘Many sampling formulas are available for processes in baseband (-a,a) at the Nyquist rate a/π. However signals of telecommunications have power spectra which occupate two bands or more. We know that PNS (periodic non-uniform sampling) allow an errorless reconstruction at rate smaller than the Nyquist one. For instance PNS2 can be used in the two-bands case (-a,-b)∪(b,a) at the Landau rate (a-b)/π We prove a set of formulas which are available in cases more general than the PNS2. They take into account two sampling sequences which can be periodic or not and with same mean rate or not.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10874091,2006CB921205,and 108471507)Shandong Provincial Natural Science Foundation,China (Grant No.ZR2009AM026)
文摘We study the dynamics of an electron spin state transfer along a half-filled two-band model(TBM).It is shown that this solvable and realistic medium has an energy gap between the ground and first-excited states in the half-filled case.By connecting two qubits to two sites of the TBM,the system can accomplish a high-fidelity and long-distance quantum state transfer(QST).Moreover,numerical simulations have been performed for a finite system.The results show that the numerical and analytical results of the effective coupling strength agree well with each other.Furthermore,the investigation shows that the reduced density matrix also has high fidelity beyond the range of perturbation.
基金supported by the National Natural Science Foundation of China (22005006,21871008,22001263)the China Postdoctoral Science Foundation (2019M660298,2020T130009)
文摘The salt-inclusion materials have drawn significant attention for their manifold structural chemistry and novel physical/chemical properties.Herein,two new salt-inclusion chalcohalides,[Cs_(6)Cl][Ga_(5)GeQ_(12)](Q=S,Se),have been discovered via hightemperature flux methods.The two isostructural compounds are constructed by porous[Ga_(5)GeQ_(12)]^(5−)layers with[ClCs_(6)]^(5+)octahedra filled in the holes.The[Ga_(5)GeQ_(12)]^(5−)layer is composed of the honeycomb-like(Ga/Ge)_(18)Q_(42)rings containing(Ga/Ge)_(3)Q_(9)trimer as basic unit.The band gaps of the two compounds are 3.90 and 2.89 eV,respectively.[Cs_(6)Cl][Ga_(5)GeS_(12)]exhibits interesting two-band emission properties which are related to the intermediate-band electronic structure revealed by density functional theory(DFT)calculations.Owing to the porous layered structure,[Cs_(6)Cl][Ga_(5)GeS_(12)]exhibits topological ion exchange ability towards Cd^(2+)ions with the maximum sorption capacity of 250 mg/g and high distribution coefficient(Kd)near 106 mL/g.This work further enriches the structural diversity of salt-inclusion materials and extends their potential application range to ion exchange adsorption.
基金This work was supported by the National Natural Science Foundation of China(No.21973022)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515012353).
文摘To compare the ability of three different reconstruction procedures in restoring the posterior displacement of tibia and the posterior stability of the knee joint from 0° to 120°flexion. Methods ： Three posterior cruciate ligaments （PCL） reconstruction procedures were performed, namely two-band two-tunnel reconstruction, one-band anterior tunnel reconstruction and one-band posterior tunnel reconstruction. The posterior displacement of the tibia in relation to the femur was measured when a 200N posterior force was applied. Results： Within the flexion range of 0° to 30°, the displacement in the one-band posterior tunnel reconstruction showed little difference from that of an intact knee （P〉0.05）. But when the flexion exceeded 30°, especially when it exceeded 60°, the displacement in oneband posterior tunnel reconstruction was much greater than that of an intact knee （P〈0.01）. In two-band two-tunnel reconstruction and one-band anterior tunnel reconstruction, the displacement was approximately the same as that of an intact knee ranging from 0° to 120° （P〉0.05）, while a slight over-restriction might be found at some angles. Conclusions： Two-band reconstruction could effectively restrict the posterior displacement of the tibia and restore anterior, posterior stability of the knee joint within its full range of flexion. One-band anterior tunnel reconstruction also could maintain the posterior stability of the knee, while the result of one-band posterior tunnel reconstruction is the most unsatisfactory.
基金Supported by National Natural Science Foundation of China under Grant No.11374017
文摘In the present paper, we investigate the existence of ferromagnetism in a two-band Hubbard model, by applying a recently-introduced method by us to study ferromagnetism in metallic dusters. We prove rigorously that the ground state of this model is ferromagnetic if the intra-orbital Coulomb repulsion between electrons is infinitely strong and only one hole exists in the system. Our theorem improves a previous result. Furthermore, our method can also be applied to dead with the case of multiple holes.
