A novel red-emitting K2（Ge,Si）F6：Mn^4＋ phosphor with uniform morphology was synthesized by co-precipitation method. The pure K2GeF6 phase with P63 mc space group other than P3m1 space group was affirmed just by in...A novel red-emitting K2（Ge,Si）F6：Mn^4＋ phosphor with uniform morphology was synthesized by co-precipitation method. The pure K2GeF6 phase with P63 mc space group other than P3m1 space group was affirmed just by incorporation of Si in K2GeF6 at room temperature according to XRD characterization. SEM images showed lamellar and octahedron grain morphology for K2GeF6：Mn^4＋ and K2（Ge,Si）F6：Mn^4＋ phosphors, respectively. It was also found that the photoluminescence excitation（PLE） and photoluminescence（PL） showed slight displacement in K2GeF6：Mn^4＋ and K2（Ge,Si）F6：Mn^4＋ system. And the zero-phonon line（ZPL） of the PL spectrum of K2GeF6：Mn^4＋ with Si showed a strong peak. Meanwhile crystalline field surrounding Mn^4＋ changes could affect the decay time in this fluoride system. The color gamut of the LED devices based on K2（Ge,Si）F6：Mn^4＋ and K2GeF6：Mn^4＋ reached up to 94.58% NTSC（National Television Standards Committee） and 94.386% NTSC, respectively, that was much higher than that based on nitride red phosphors. All these original characteristics in K2（Ge,Si）F6：Mn^4＋ phosphor are desirable for potential applications as a red phosphor for improving lighting and display quality of conventional white LEDs.展开更多
The paper reviews previous publications and reports some comments about a semi empirical model of the growth and decay process of a planktonic microbial culture. After summarizing and reshaping some fundamental mathem...The paper reviews previous publications and reports some comments about a semi empirical model of the growth and decay process of a planktonic microbial culture. After summarizing and reshaping some fundamental mathematical expressions, the paper highlights the reasons for the choice of a suitable time origin that makes the parameters of the model self-consistent. Besides the potential applications to predictive microbiology studies and to effects of bactericidal drugs, the model allows a suitable proxy of the fitness of the microbial culture, which can be of interest for the studies on the evolution across some thousand generations of a Long Term Evolution Experiment.展开更多
Linear Alkyl Benzene （LAB） is a promising liquid scintillator solvent in neutrino experiments because it has many appealing properties. The timing properties of LAB-based liquid scintillator have been studied throug...Linear Alkyl Benzene （LAB） is a promising liquid scintillator solvent in neutrino experiments because it has many appealing properties. The timing properties of LAB-based liquid scintillator have been studied through ultraviolet and ionization excitation in this study. The decay time of LAB, PPO and bis-MSB is found to be 48.6 ns, 1.55 ns and 1.5 ns, respectively. A model can describe the absorption and re-emission process between PPO and bis-MSB perfectly. The energy transfer time between LAB and PPO with different concentrations can be obtained via another model. We also show that the LAB-based liquid scintillator has good （n, γ） and （α, γ） discrimination power.展开更多
基金Project supported by the Major State Basic Research Development Program of China(National Basic Research Program of China)(2014CB643801973)
文摘A novel red-emitting K2（Ge,Si）F6：Mn^4＋ phosphor with uniform morphology was synthesized by co-precipitation method. The pure K2GeF6 phase with P63 mc space group other than P3m1 space group was affirmed just by incorporation of Si in K2GeF6 at room temperature according to XRD characterization. SEM images showed lamellar and octahedron grain morphology for K2GeF6：Mn^4＋ and K2（Ge,Si）F6：Mn^4＋ phosphors, respectively. It was also found that the photoluminescence excitation（PLE） and photoluminescence（PL） showed slight displacement in K2GeF6：Mn^4＋ and K2（Ge,Si）F6：Mn^4＋ system. And the zero-phonon line（ZPL） of the PL spectrum of K2GeF6：Mn^4＋ with Si showed a strong peak. Meanwhile crystalline field surrounding Mn^4＋ changes could affect the decay time in this fluoride system. The color gamut of the LED devices based on K2（Ge,Si）F6：Mn^4＋ and K2GeF6：Mn^4＋ reached up to 94.58% NTSC（National Television Standards Committee） and 94.386% NTSC, respectively, that was much higher than that based on nitride red phosphors. All these original characteristics in K2（Ge,Si）F6：Mn^4＋ phosphor are desirable for potential applications as a red phosphor for improving lighting and display quality of conventional white LEDs.
文摘The paper reviews previous publications and reports some comments about a semi empirical model of the growth and decay process of a planktonic microbial culture. After summarizing and reshaping some fundamental mathematical expressions, the paper highlights the reasons for the choice of a suitable time origin that makes the parameters of the model self-consistent. Besides the potential applications to predictive microbiology studies and to effects of bactericidal drugs, the model allows a suitable proxy of the fitness of the microbial culture, which can be of interest for the studies on the evolution across some thousand generations of a Long Term Evolution Experiment.
基金Supported by National Natural Science Foundation of China (10890094, 11011120080)
文摘Linear Alkyl Benzene （LAB） is a promising liquid scintillator solvent in neutrino experiments because it has many appealing properties. The timing properties of LAB-based liquid scintillator have been studied through ultraviolet and ionization excitation in this study. The decay time of LAB, PPO and bis-MSB is found to be 48.6 ns, 1.55 ns and 1.5 ns, respectively. A model can describe the absorption and re-emission process between PPO and bis-MSB perfectly. The energy transfer time between LAB and PPO with different concentrations can be obtained via another model. We also show that the LAB-based liquid scintillator has good （n, γ） and （α, γ） discrimination power.
