In this paper we propose an Ising model on an infinite ladder lattice, which is made of two infinite Ising spin chains with interactions. It is essentially a quasi-one-dimessional Ising model because the length of the...In this paper we propose an Ising model on an infinite ladder lattice, which is made of two infinite Ising spin chains with interactions. It is essentially a quasi-one-dimessional Ising model because the length of the ladder lattice is infinite, while its width is finite. We investigate the phase transition and dynamic behavior of Ising model on this quasi-one-dimessional system. We use the generalized transfer matrix method to investigate the phase transition of the system. It is found that there is no nonzero temperature phase transition in this system. At the same time, we are interested in Glauber dynamics. Based on that, we obtain the time evolution of the local spin magnetization by exactly solving a set of master equations.展开更多
The Tb3＋single-doped and Tb3＋-Yb3＋co-doped glass ceramics with the precipitation of CaF2, CaF2-SrF2 solid state solu-tion and SrF2 nanocrystals were designed and prepared by taking different amounts of CaF2 and SrF...The Tb3＋single-doped and Tb3＋-Yb3＋co-doped glass ceramics with the precipitation of CaF2, CaF2-SrF2 solid state solu-tion and SrF2 nanocrystals were designed and prepared by taking different amounts of CaF2 and SrF2 as the starting fluorides to inves-tigate the influence of the crystalline phase on the total quantum efficiency. The formation of the fluoride nanocrystals and the incor-poration of the doped rare earth ions into the fluoride nanocrystals were proved by the XRD measurement. The energy transfer from Tb3＋to Yb3＋was studied by the steady and time resolved spectra. The total internal quantum efficiencies were calculated based on the measured Tb3＋lifetime, which was about 10.5%improved in the SrF2 nanocrystals precipitated glass ceramics compared with that in the CaF2 nanocrystals precipitated glass ceramics mainly due to the lower phonon energy environment. Meanwhile, the total external quantum efficiencies were evaluated with the integrating sphere measurement system, which were 18.6%, 19.3%and 24.4%, respec-tively, for the CaF2, CaF2-SrF2 and SrF2 nanocrystals precipitated glass ceramics. Additionally, obvious difference between the calcu-lated total internal quantum efficiency and the measured total external quantum efficiency was also discussed.展开更多
文摘In this paper we propose an Ising model on an infinite ladder lattice, which is made of two infinite Ising spin chains with interactions. It is essentially a quasi-one-dimessional Ising model because the length of the ladder lattice is infinite, while its width is finite. We investigate the phase transition and dynamic behavior of Ising model on this quasi-one-dimessional system. We use the generalized transfer matrix method to investigate the phase transition of the system. It is found that there is no nonzero temperature phase transition in this system. At the same time, we are interested in Glauber dynamics. Based on that, we obtain the time evolution of the local spin magnetization by exactly solving a set of master equations.
基金Project supported by the Basic Research Project of Shanghai Science and Technology Commission(12JC1408500)
文摘The Tb3＋single-doped and Tb3＋-Yb3＋co-doped glass ceramics with the precipitation of CaF2, CaF2-SrF2 solid state solu-tion and SrF2 nanocrystals were designed and prepared by taking different amounts of CaF2 and SrF2 as the starting fluorides to inves-tigate the influence of the crystalline phase on the total quantum efficiency. The formation of the fluoride nanocrystals and the incor-poration of the doped rare earth ions into the fluoride nanocrystals were proved by the XRD measurement. The energy transfer from Tb3＋to Yb3＋was studied by the steady and time resolved spectra. The total internal quantum efficiencies were calculated based on the measured Tb3＋lifetime, which was about 10.5%improved in the SrF2 nanocrystals precipitated glass ceramics compared with that in the CaF2 nanocrystals precipitated glass ceramics mainly due to the lower phonon energy environment. Meanwhile, the total external quantum efficiencies were evaluated with the integrating sphere measurement system, which were 18.6%, 19.3%and 24.4%, respec-tively, for the CaF2, CaF2-SrF2 and SrF2 nanocrystals precipitated glass ceramics. Additionally, obvious difference between the calcu-lated total internal quantum efficiency and the measured total external quantum efficiency was also discussed.
