Low lying excited states of beryllium are calculated with multiconfiguration interaction method. The relativisitic corrections and mass polarization are included. The oscillator strength and radiation rates are also ...Low lying excited states of beryllium are calculated with multiconfiguration interaction method. The relativisitic corrections and mass polarization are included. The oscillator strength and radiation rates are also calculated. Our results are in good agreement with other theoretical data.展开更多
The effects of exciton-optical phonon interaction on the binding energy and the total and reduced effective masses of an exciton in a cylindrical quantum wire have been investigated. We adopt a perturbative-PLL [T.D. ...The effects of exciton-optical phonon interaction on the binding energy and the total and reduced effective masses of an exciton in a cylindrical quantum wire have been investigated. We adopt a perturbative-PLL [T.D. Lee,F. Low, and D. Pines, Phys. Rev. B90 (1953) 297] technique to construct an effective Hamiltonian and then use a variational solution to deal with the exciton-phonon system. The interactions of exciton with the longitudinal-optical phonon and the surface-optical phonon have been taken into consideration. The numerical calculations for GaAs show that the influences of phonon modes on the exciton in a quasi-one-dimensional quantum wire are considerable and should not be neglected. Moreover the numerical results for heavy- and light-hole exciton are obtained, which show that the polaronic effects on two types of excitons are very different but both depend heavily on the sizes of the wire.展开更多
The dominant feature of the work of many specialists on the design of the internal combustion engine is to achieve the possible lowest fuel consumption, which is the most convenient measure of the efficiency of the th...The dominant feature of the work of many specialists on the design of the internal combustion engine is to achieve the possible lowest fuel consumption, which is the most convenient measure of the efficiency of the thermodynamic cycle. From the very beginning of this heat machine, there are many of solutions that are better or worse fit to the global development trend. In this paper, the authors suggest the possibility closer to the optimal solution by introducing structural active zones, where the task is instantaneous(during one cycle) heat transfer to the skin layer on elements of the combustion chamber and to transfer part of the recovered heat to the next cycle, reaching a growth effect of the useful efficiency by 10% to 20%. The solution is different from the ones used by the fact that it is only partially insulating barrier, and the main goal is focused on supporting the next thermal cycle by which it is possible to affect as mentioned above. This paper describes the idea of the functioning of the active combustion chamber and pointed out the technical capabilities of its creation.展开更多
In this work,we study environment-assisted excitation energy transfer(EET) through calculating energy transfer efficiency(ETE) in LH1-RC-type and LH2-type trimers,which can be used to mimic energy transfer behaviors i...In this work,we study environment-assisted excitation energy transfer(EET) through calculating energy transfer efficiency(ETE) in LH1-RC-type and LH2-type trimers,which can be used to mimic energy transfer behaviors in the basic unit cells of LH1-RC and LH2 light-harvesting complexes.Quantum state evolution of the trimers is described by a non-Hermitian quantum master equation.ETE in these trimer systems is investigated by the use of numerical solutions at finite temperatures for the non-Hermitian master equation.We theoretically reveal the temperature-assisted ETE enhancement.It is found that highly efficient EET with nearly unit efficiency may occur in the nearby regime of the critical point of quantum phase transition.展开更多
Pr3+and Yb3+co-doped phosphate glasses are prepared to study their optical properties.Excitation and emission spectra and decay curves are used to characterize their luminescence.We demonstrate that upon excitation of...Pr3+and Yb3+co-doped phosphate glasses are prepared to study their optical properties.Excitation and emission spectra and decay curves are used to characterize their luminescence.We demonstrate that upon excitation of Pr3+ion with one high energy photon at 470 nm,two near-infrared(NIR)photons are emitted at 950-1100 nm(Yb3+:2F 5/2 →2F 7/2)through an efficient cooperative energy transfer(CET)from Pr3+to Yb3+.The maximum energy transfer efficiency(ETE)and the corresponding quantum efficiency approach up to 90.17%and 190.17%,respectively.The glass materials might find potential application for improving the efficiency of silicon-based solar cells.展开更多
文摘Low lying excited states of beryllium are calculated with multiconfiguration interaction method. The relativisitic corrections and mass polarization are included. The oscillator strength and radiation rates are also calculated. Our results are in good agreement with other theoretical data.
文摘The effects of exciton-optical phonon interaction on the binding energy and the total and reduced effective masses of an exciton in a cylindrical quantum wire have been investigated. We adopt a perturbative-PLL [T.D. Lee,F. Low, and D. Pines, Phys. Rev. B90 (1953) 297] technique to construct an effective Hamiltonian and then use a variational solution to deal with the exciton-phonon system. The interactions of exciton with the longitudinal-optical phonon and the surface-optical phonon have been taken into consideration. The numerical calculations for GaAs show that the influences of phonon modes on the exciton in a quasi-one-dimensional quantum wire are considerable and should not be neglected. Moreover the numerical results for heavy- and light-hole exciton are obtained, which show that the polaronic effects on two types of excitons are very different but both depend heavily on the sizes of the wire.
文摘The dominant feature of the work of many specialists on the design of the internal combustion engine is to achieve the possible lowest fuel consumption, which is the most convenient measure of the efficiency of the thermodynamic cycle. From the very beginning of this heat machine, there are many of solutions that are better or worse fit to the global development trend. In this paper, the authors suggest the possibility closer to the optimal solution by introducing structural active zones, where the task is instantaneous(during one cycle) heat transfer to the skin layer on elements of the combustion chamber and to transfer part of the recovered heat to the next cycle, reaching a growth effect of the useful efficiency by 10% to 20%. The solution is different from the ones used by the fact that it is only partially insulating barrier, and the main goal is focused on supporting the next thermal cycle by which it is possible to affect as mentioned above. This paper describes the idea of the functioning of the active combustion chamber and pointed out the technical capabilities of its creation.
基金supported by the National Fundamental Research Program (Grant No. 2007CB925204)the National Natural Science Foundation of China (Grant Nos. 11075050 and 10775048)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT0964)the Hunan Provincial Natural Science Foundation (Grant No. 11JJ7001)
文摘In this work,we study environment-assisted excitation energy transfer(EET) through calculating energy transfer efficiency(ETE) in LH1-RC-type and LH2-type trimers,which can be used to mimic energy transfer behaviors in the basic unit cells of LH1-RC and LH2 light-harvesting complexes.Quantum state evolution of the trimers is described by a non-Hermitian quantum master equation.ETE in these trimer systems is investigated by the use of numerical solutions at finite temperatures for the non-Hermitian master equation.We theoretically reveal the temperature-assisted ETE enhancement.It is found that highly efficient EET with nearly unit efficiency may occur in the nearby regime of the critical point of quantum phase transition.
基金supported by the National Natural Science Foundation of China(Nos.61275180,51272109and50972061)the Natural Science Foundation of Zhejiang Province(Nos.Z4110072and R4100364)+1 种基金the Opening Foundation of Zhejiang Provincial Top Key DisciplineK.C.Wong Magna Fund in Ningbo University
文摘Pr3+and Yb3+co-doped phosphate glasses are prepared to study their optical properties.Excitation and emission spectra and decay curves are used to characterize their luminescence.We demonstrate that upon excitation of Pr3+ion with one high energy photon at 470 nm,two near-infrared(NIR)photons are emitted at 950-1100 nm(Yb3+:2F 5/2 →2F 7/2)through an efficient cooperative energy transfer(CET)from Pr3+to Yb3+.The maximum energy transfer efficiency(ETE)and the corresponding quantum efficiency approach up to 90.17%and 190.17%,respectively.The glass materials might find potential application for improving the efficiency of silicon-based solar cells.
